Abstract:Trichogramma is adopted in biological agriculture because it is environmental friendly and has high efficiency in preventing pests. However, different from traditional liquid pesticides, trichogramma comes in small pill, which is difficult for manual dispensing, especially in Northeast China where corn is the main crop. Based on biological control and agricultural unmanned aerial vehicles (UAV) technology, this article proposed a trichogramma delivering system using Hex-Rotor UAV. The trichogramma autonomous delivery function was achieved through GPS and Google earth map. The Hex-Rotor’s basic structure and operating principle were explained, and a special trichogramma delivering device was designed. The entire system weighs 9kg at full load, and the UAV can fly for more than 20 min at the speed of 10m/s, complete serving an area of over 10hm2 on a single flight. A backstepping control algorithm with extended state observer (ESO) and fast differentiator was adopted, and the UAV can finish the trajectory tracking flight against external interference winds. Finally, the unit operation area of the delivery system reached 9700m2/min in practical tests. The trichogramma coverage was estimated almost 100% under ideal conditions, and work omission was 0. Experiments prove that this trichogramma delivering system possesses high stability and reliability, and can realize UAV autonomous biological control.

Abstract:The small-scale unmanned helicopter is well-known by its hovering capabilities. However, it exhibits a nonlinear and complex dynamic phenomenon, and it is a loop unstable, high degree of inter axis coupling system. The goal of autonomous flight was realized based on an accurate and appropriate helicopter model. And system identification is the practical method to obtain the model. Aiming at the system identification of a small-scale unmanned helicopter in hover condition, a novel algorithm combined prediction error method with artificial bee colony algorithm (PEM-ABC) was proposed. In the proposed algorithm, the problem of system identification was turned into an optimization problem. The search scope was arranged by the PEM algorithm; in that case, the initial solutions can be obtained. And in the stage of employed bee search, an adaptive search strategy was adopted to increase the speed of convergence. In the stage of following bee search, a new probability of selection strategy was introduced to keep the diversity of the population. And in the stage of scout bee search, the chaotic search operator was used to improve the ability of global search. Through the actual flight data collected by airborne equipment, the model used in system identification was validated and analyzed. The results show that the unknown parameters can be estimated based on the proposed algorithm. Compared to PEM algorithm and traditional ABC algorithm, the identified accuracy of the proposed algorithm was better, which showed an important engineering application value.

Abstract:A pulse width modulation (PWM) variable spraying system based on miniature unmanned aerial vehicle was developed, and based on controllable multi-speed environment, a droplet deposition test through droplets concentration method was studied for the PWM spraying system when the UAV was hovering. The system is consisted of airborne spraying device and ground measurement and control unit. The airborne spraying device with the MCU of STM32F103VC was remotely controlled by the ground measurement and control unit which was developed by LabWindows/CVI through wireless data transmission module. Frequency of 10Hz square wave and adjustable duty ratio were evaluated to control micro electric diaphragm pump, and then pressure and flow rate of the system were changed. The experiments were carried on under the condition of different distance and wind speed to get the relationship among deposition volume, duty ratio, nozzle type, and the rotate speed of centrifugal nozzle. The results showed that wind speed was the most significant factor influencing the droplet deposition. Deposition volume was distributed in a parabolic type in the collection area, gradually decreased and the deposition peak was far away from the nozzle with increasing of wind speed. Droplet diameter was not very important to deposition when wind speed was smaller than 3m/s. When the wind speed was greater or equal to 3m/s, the droplet was drifted of different diameters, and the deposition volume reduced significantly and moved away from the nozzle. Small droplet size (101.74μm) was much easier to be drifted, and the peak concentration was 4m far from the nozzle. Also the deposition volume of small droplet size was much lower than droplet size of 164.00μm and 228.16μm. The optimization of spraying parameters and a theoretical support to improve the quality of aviation operations were provided by the results.

Abstract:In order to meet the demand of precise management on mechanization of straw returning to field operations, the difficulties were solved as follows: firstly, the area statistics of each landblock is hard. Secondly, the onsite verification needs a lot of people as well as lots of time. Finally, the manage department can not get the present situation on time. Therefore, it is in great demand to establish the precision management system for mechanized straw returning. The system integrated the Beidou satellite navigation and positioning system(BDS), the internet of things, geographic information systems and other new generation information technologies. The work carried out two parts. One part, the vehicle positioning terminal based on Beidou was established for agricultural machinery, which can realtime acquisite, and process the location and status data of agricultural machinery. The other part, the precision management system for mechanized straw returning was developed and implemented by using several functions including operation monitoring, landblock identification, area measurement, quality evaluation, index statistics and dispatching function, etc. The test results show that it can effectively control agricultural machinery operation trajectory, flexible scheduling, real time implementation of classified statistics and analysis, improve the efficiency of management of the returning operation. At the same time, the results reached the working precision in landblock identification and landblock area statistic, which can satisfy the demand of mechanization from straw to field operations.

Abstract:Considering the fact that uncertain tire sliding and uncertain pavement lead to trajectory of tractor could not be accurately described by kinematic model, a pure pursuit control method based on SVR inversemodel was proposed for agricultural machine navigation. This paper analyzed and determined the main structure and technical parameters of the method. The inversemodel of forward heading in tractor was established by using the method of granular support vector regression, and the corresponding relation function of kinematic theoretical curvature and actual curvature was obtained. The error of the output of the pure pursuit navigation model was corrected by inversemodel, thus the adaptability and dynamic performance of pure pursuit control method were improved. The path tracking experiments carried out on navigation system of the tractor and the pavement experiment results showed that the maximum of linear tracing pitch yaw roll error was less than 0.0614m, when the speed of agricultural machinery was 1.2m/s and path length was longer than 125m. Compared with the method of conventional pure pursuit navigation model, the pure pursuit control method based on SVR inversemodel has better linear racing performance. Field experiment results concluded that the maximum lateral deviation was 0.0887m, when the running speed of the tractor was 0.5m/s, and the proposed controller significantly improved precision of field experiment. Based on the path tracking experiments and field experiments results, the navigation control method could be applied to automatic rowcontrolled operation of 2BFQ-6 type directseeding combined dual purpose planter for rapeseed.

Abstract:Respect to the character that the gearbox shifting resistance exist in the fourwheel minitype agricultural tractor is timevarying and nonlinear and the special requirement that the gear shift lever has to be released after shifting, this paper designed a novel gear shift mechanical arm for tractor robot driver. This manipulator is joint type. According to the manipulator’s operating characteristic, this paper applied D-H method to establish the coordinate transformation matrix. Based on the kinematics analysis on the manipulator, Lagrange equation was used to simplify kinetic model of the manipulator. SolidWorks and ADAMS were applied to establish the virtual prototype model of the manipulator and to do kinematic and dynamic simulation respectively. In order to guarantee the smoothness of shift, the distance between the terminal of the manipulator’s actuator and the gear shift lever of the tractor was set to less than 50mm. The absolute value of terminal actuator’s minimum jitter speed during shift was optimized as the objective function. The target function is optimal when the length of shift manipulator is 220.0mm and the height of the terminal is 393.25mm. After optimization, the jitter speed fluctuation is 28.18% less than before. The rate of change of average displacement and average acceleration are 49.55% and 52.05%. At the same time, the peak value of the displacement, velocity and acceleration are 60.22%, 66.24% and 81.66%, respectively. Through the simulation, the optimization of the parameters of the manipulator, the rationality and the scientificity of the model are verified. Finally, through the experiment on gear shift mechanical arm on JINMA 300E tractor, the result shows that the gear mechanical arm can realize the goal to shift different gears smoothly. In addition, the design of the gear mechanical arm can complete some complicated actions of tractor’s driver. Thus, the gear shift mechanical arm has excellent engineering and application value.

Abstract:In order to improve tea quality and efficiency of plucking by using the teaplucking machine, this paper proposed a kind of identification method of the tea ridge and navigation method of the teaplucking machine. Firstly, the inside and outside parameters of camera offline were calibrated, which were put in the front of teaplucking machine for getting the video information about the tea ridge. Secondly, the Gauss filter method was used to reduce noise jamming, and after customizing the rectangular window, the local OTSU thresholds method was used to segment image, the image was obtained by the camera. Then the points which belonged to the edge lines of the tea ridge were found and noted based on space constraint, the space constraint can improve the speed and the accuracy to find the points. Least square linear fitting method was used to fit the left and right edge lines of the tea ridge. Then the center line of the ridge was calculated according to the calibration results, and the state of the teaplucking machine, including the center line of the ridge and the offset of the teaplucking machine, was showed on the screen of the driver’s seat in order to prompt the driver how to adjust the machine. Experimental results show that this method can identify the tea ridge accurately and navigate the teaplucking machine, and also can solve the disadvantages of cutting leaves with too many old leaves, and lay a solid foundation for fully autocutting type teaplucking machine in the future.

Abstract:Due to the high cost of plant factory, we put forward a logistics handling robot, worked in a wide range but took up a narrow space when in nonworking state, based on plant factory. First, we introduced its work environment and task characteristics. The space, which the robot takes up, needs to be minimized as far as possible, what’s more, the optimal trajectory must ensure that the distance between the robot and the seeding platform reaches the minimum. Then, we adopted D-H method to establish the connecting rod coordinate system, and analyzed the robot movement space through solving the kinematics equation. On this basis, we planned a kind of sliding handling optimal trajectory to meet the vertical cultivation characteristics of plant factory. Then, we extracted some points on the trajectory and solved the kinematics inverse solution of those points. Next, we fitted timevarying function curve of manipulator’s joint variable by using cubic spline interpolation. Last, we made a testmachine and set up a vertical seedling platform in the lab. We controlled the robot to move along the optimal trajectory with a highspeed camera recording its actual moving tracking. The test showed that the maximum absolute deviation of actual moving tracking was 8mm which was within the error range and verified the correctness of the inverse solution. So the invention can complete the needed handling work and provide a good platform for the following study of plant factory.

Abstract:The strawsoilrotary tool interaction plays a pivotal role in the field of crop production. The simulation of strawsoilrotary blade interaction using distinct element method (DEM) could be hypothesized to provide a better understanding of the straw movement. Firstly, DEM model of strawsoilrotary blade interaction was established. Secondly, indoor soil bin experiments were conducted to verify simulation model, positions of straw particle at every moment were used to study straw displacement in simulation and tracer method was employed to measure straw displacement in experiments. Both simulation and experiment were performed with four rotational blade speeds (77r/min, 100r/min, 123r/min, 146r/min) at constant forward speed of 0.222m/s and depth of 100mm. The straw displacement both in soil bin and simulation increased with increasing rotational speed of blade. Moreover, the displacement in forward direction was larger than that of side direction at all rotational speeds in both experiment and simulation. The average error of straw displacement between simulated results and experimental results was about 40% for higher rotational speed while 70% for lower ones. The relation equation between relative error and rotational speed can be used to predict the experimental values, and the error between the predicted ones and experimental ones were 8.7% and 9.3% for forward and side displacements. Microscopic movements of straws were analyzed by tracing three specific straw particles. The movement of straw near sidelong edge or lengthwise edge was affected by cutting edges, the straw located at inner side of sidelong edge slipped off along the border of sidelong edge when rotary blade started to cut the soil while the straw near lengthwise edge was pushed to move along the lengthwise edge at the initial stage of soil cutting and later was tossed upward. The movement of straw away from cutting range was only affected by soil disturbance. The straw particles near lengthwise edge or transition edge could be buried directly during tillage. It is recommended to increase the ration of straw burial during tillage by optimizing edge curve and improve dispersed homogeneous degree by selecting the optimal operational parameters of rotary blade.

Abstract:A key facility for tillage and seeding implements testing is the experimental soil tillage platform, which is generally constructed in the indoor soilbins. However, soil structure and workability of the field state soil is not attainable with laboratory remolding procedures. Based on the previous works, a multifunctional soil tillage testing platform for insitu experiment was developed, serving as a specialized experimental equipment for various types of tractive or propelled tillage tools. This platform inherited the benefits of indoor soil bin systems, e.g. precision control, high interchangeability, adaptable to multiple testing tools and experimental plans. Being designed in a structure of supported frame and rail systems, the whole platform can be hoisted and loaded on a track for transportation. The four supporting beams sat on rails laid on soil surface, facilitating transversal and longitudinal movement, maneuvering from one field to another, as well as positioning for precision control for testing and measurement. Different tillage tools can be hooked on a multipurpose testing cart, on which complete set of sensors and power supply unit were supplied for propelling the attached tools and data collection. Two guidings railed on the platform guided the multipurpose testing cart, which was tracked by an electric driving mechanism. The forwarding speed was adjustable in a range of 0~1m/s. The four synchronous electric motors situated on the four supporting beams facilitated overall elevating movement of the platform and adjusted the working depth of tillage tools. Total attainable vertical displacement from both the platform movement and the screw mechanism of the testing cart can be 80cm, satisfying different experimental demands. A complete electrical power and control system was designed, which highly improved the degree of electrification. Trial test in field showed that the developed system was suitable for insitu multifactor and multilevel experimental test.

Abstract:Paddy rice is one of the most important fine food crops that feed the largest proportion of the world’s population. There are two planting patterns of paddy rice called direct seeding and transplanting. In order to realize precision hill direct seeding of hybrid rice in field and solve the problem of budded seed overhead and jaming in seeding box, a pneumatic seed metering device for hybrid rice budded seed was designed based on the seeding principle of air suction-air blowing. The seed metering device used cam, pushing rod and combing strips to solve the problem of rice budded seeds’ mobility. The seeding plate which had groups of suction holes could absorb 2~4 rice budded seeds. The seed metering device was constituted by seed box, cam, push rod, seeding axis, seeding plate, air chamber, flange and so on, by which two to four bud seeds could be sucked and dropped at the same time. The adsorption mechanism of budded seed in seed filling area was analyzed in the paper theoretically. An equation of vacuum degree in suction chamber was built. The paper launched bench experiment of doublesided pneumatic seed metering device and studied the relationship between seeding performance and combing device，rotational speed of seeding plate. The orthogonal experiment was done which took the diameter of suction hole, rotational speed of seeding plate and vacuum degree of air chamber as factors. The experiment result showed that the combing strips could stir rice budded seeds. The orthogonal experiment indicated that the optimal condition for the seed metering device is as follows: when the rotational speed is 15r/min, the vacuum degree is 3.5kPa and the diameter of suction hole is 1.6mm. And the experiment in field indicated that the device meets the agronomic requirement of planting rice budded seed.

Abstract:The furrow sowing with whole plastic-film mulching on double ridges had been widely used in the arid region of northwest China, because it could resist drought and increase production. So the mechanical plowing and filming on seedbed was an inevitable trend in farming. For further study of the improved working performance of operation machine for tillagefertilization and sprayingfilming on double ridges, the Box-Behnken experimental design with four factors and three levels was performed, parameters such as operation machine speed, soil elevator speed, lateral flow angle of covering unit and straight flow angle of covering unit were selected as independent variables, which would influence mechanical damage rate of daylighting mulch. The mathematical model was established, then the effects of various parameters and their interactions were analyzed as well. The test results showed that effects order of four parameters on mechanical damage rate of daylighting mulch were as follows: soil elevator speed, operation machine speed, lateral flow angle of soil covering unit and straight flow angle of soil covering unit. The optimal working parameters were combined operation machine speed of 0.67m/s, soil elevator speed of 070m/s, lateral flow angle of soil covering unit of 75° and straight flow angle of soil covering unit of 48°. Confirmatory tests showed that the average value of mechanical damage rate of daylighting mulch was 0.216%, which compared with the optimization before, had dropped significantly, and also avoided mechanical damage of daylighting mulch under this condition.

Abstract:In order to obtain the optimum operating parameters for the dibbletype planting apparatus of vegetable pot seedling transplanter in highspeed condition, a testbed with adjusted parameters was designed and a soil trough experiment was conducted for seedling transplanting. A central composite design method of second order regression orthogonal rotation was carried out with transplanting speed, characteristic parameter and oblique angle of dibble as experimental factors and with qualification ratio of perpendicularity, variation coefficient of planting spacing and qualification ratio of planting depth as response values. By using SAS 9.1 regression analysis method and response surface method, both single factor and interactive factor on response values were analyzed. Combined with nonlinear optimization calculation method, the structural parameters and working parameters were calculated optimally. The results obtained in the condition of high transplanting speed (90 seedlings per minute) indicated that, in terms of significant degree, the influence factors of qualification ratio of perpendicularity were oblique angle of dibble, characteristic parameter and transplanting speed; the influence factors of variation coefficient of planting spacing were transplanting speed, characteristic parameter and oblique angle of dibble; the influence factors of qualification ratio of planting depth were transplanting speed, oblique angle of dibble and characteristic parameter. The optimum parameter condition of the dibbletype planting apparatus after optimizing was 0.47m/s of transplanting speed, 1.18 of characteristic parameter and 87° of oblique angle of dibble. At this time, qualification ratio of perpendicularity achieved theoretical optimum value of 98.01%, variation coefficient of planting spacing was 5.93%, and qualification ratio of planting depth was 89.25%. Through verification by an experiment in optimum condition, the experimental value of qualification ratio of perpendicularity was 96.6%, variation coefficient of planting spacing was 6.1%, and qualification ratio of planting depth was 87.8%, which indicated that the experimental results and predicted results were consistent, and regression models established by the experiment were appropriate. According to comparison of transplanting performance before and after parameter optimization, qualification ratio of perpendicularity and qualification ratio of planting depth increased by 5.8 percent and 3.6 percent respectively, and transplanting performance was superior to the technique indexes of national and industry standards as well.

Abstract:In order to improve the mechanized spraying effect of stunted and close planting cotton, an airassisted cotton boom sprayer with separating row and spraying in inside and upper canopy by combining separating row and spraying inside canopy technology with airassisted spraying technology was designed. This sprayer braced the droplet diffusion space of inside cotton canopy by row separator and improved droplet diffusion range and distribution uniformity by airflow disturbance and transport of inside and upper cotton canopy. The structure of airassisted boom sprayer and the design of row separator were described. The airassisted system was designed by combining substitution principle with end speed principle. The design method of air duct outlet was elaborated. The airassisted cotton boom sprayer was tested by wind field test and spray deposit distribution test. Wind field test showed wind velocity of the air flow field was big enough and welldistributed. Spray deposit distribution test showed the front leaves average droplet coverage of inside cotton canopy was 65.30% and the back leaves average droplet coverage of inside cotton canopy was 3983%. The biggest difference of front leaves average droplet coverage among upper canopy, middle canopy and lower canopy was 10.25% and the biggest difference of back leaves average droplet coverage among upper canopy, middle canopy and lower canopy was 11.75%.The spray deposit distribution uniformity of the whole cotton canopy was good and the spraying effect was improved obviously.

Abstract:Considering the many difficulties of installing the sensor for the soil temperature and moisture measurement, such as miserable installation of the sensor and relatively large disturbance to the local soil, this paper designed a composite sensor for multilayer soil profile in accordance with the principles of soil moisture measurement and temperature measurement based on SWR and platinum resistance. A vector network analyzer and HFSS electromagnetic simulation software were used to analyze impedance characteristic and electric field distribution of the sensor electrode. According to the analysis result, the structure of copper detection probe was designed. The diameter of the probe is 5cm, the width is 2.5cm, the thickness is 0.09cm and the excitation frequency of test circuit is 100MHz. Three types of soil were choosen as experimental samples. The polynomial fitting and linear fitting were conducted on the output values of sensor detection unit. The results correlation reached more than 099.The static and dynamic performance of the system met the detection requirements of temperature and moisture of soil profile. Experiments was carried out in Xiaotangshan District, Beijing City, and then effect of temperature and volumetric moisture content of soil on sensor outputs were analyzed and correction models were established by using the statistical regression method at different temperatures. The sensor working in the PVC pipe buried in the soil could obtain the information of temperature and moisture of the three layers, and its performance was stable and the data was reliable. This study provides a highly efficient method for obtaining the realtime information of multilayer soil moisture and temperature.

Abstract:Ion selective electrode (ISE) is a quick and lowcost method of soil nitratenitrogen detection. Aiming at improving the accuracy of ISE based soil nitratenitrogen detection, influences of ISE signal characteristics (small signal of millivolt level and high internal resistance) and environmental factors (noise and temperature influence) on detection precision were discussed at first. Second, how to improve the accuracy was researched. For antiinterference and collection of accurate ISE potential, signal conditioning module including impedance transformation, filtering and amplification was added to detection circuit. Besides, measurement model was amended by software temperature correction for decreasing the influence of temperature. And then, two groups of contrast experiments were designed and conducted. One was the collection of ISE potential signals measured by detection circuit with impedance transformation and filtering module and by detection circuit without this module. The other one was the detection of soil nitratenitrogen content measured by linear regression model and temperature correction model. The results show that in the condition of high frequency noise, measuring error of detection circuit with impedance transformation and filtering module comparing with ion meter is less than 1mV. It has high accuracy and antiinterference ability. And when the environment temperature changes, relative error of soil nitratenitrogen content between temperature correction model and ion chromatography method is less than 8.20% and correlation coefficient R attains to 0.9986. The result of reducing error and improving accuracy is effective.

Abstract:Due to the complexity of the fluid field in hydrocyclone and the difficulty of mastering the law of sediment motion, an Eulerian-Lagrange liquid-solid multiphase turbulence model combined with the kinetic theory of granular flow was used to carry out simulation based on coupled CFD-DEM watersediment twophase flow in a hydrocyclone, which analyzed the trochoid and speed of single sediment, speed of sediment group, the moving pattern and distribution of sediment group. The simulation results show that the smaller the sediment size was, the closer the distance was, the more easily uprising from downward trend to upstream, and the more difficult to be separated. For the particles of 40μm in diameter, sediment peak appeared in the interface of cylinder and cone and the separation effect of sediment was easy to be affected. But for the particles of 50μm and 60μm, sediment peak appeared in cone part and sediment had a better separation effect. Through tracking single sediment and sediment group, it can be found that the sediment almost stay in circular motion in cylinder. In cone part, sediment not only stays in circular motion but also obviously runs in line movement when they enter in sediment settling. Analyzing the moving pattern and distribution of single sediment and sand group provides a microscopic method for understanding separation efficiency and also provides an effective research method for the further study of the hydrocyclone performance.

Abstract:A test on water application uniformity of center pivot system and field experiment of waterfertilizer coupling on alfalfa were conducted at Saiwusu, Inner Mongolia, to evaluate the effect of water and fertilizer coupling on hay yield by center pivot system. The results show that annual water requirement is 469.4mm for alfalfa of fifth years and three harvests every year. Yield and crop water use efficiency decreased by crop, while water consumption increased. No significant differences existed in alfalfa yield between 100%ETc and 80%ETc irrigation level, but 60%ETc level caused an obvious reduction. It can obtain the best combination of yield and crop water use efficiency when using 80%ETc irrigation level for each harvest. Alfalfa applied with 90kg/hm2 phosphatepotassium compound fertilizer for the first crop and 70kg/hm2 urea fertilizer for the second crop has the highest partial factor productivity (PFP). Neither fertilizer application nor waterfertilizer coupling 〖JP3〗has no significant effect on alfalfa yield in the whole growing season. The actual irrigation amounts applied by the end gun are one third larger than that in the other circular area of the system, while the hay yield has no corresponding increase. In order to reduce waste of irrigation water, the end gun should be selected properly in center pivot irrigation system.

Abstract:Field experiments were conducted from 2012 to 2013 to determine the effects of irrigation and fertilization on tomatoes (Lycopersicum esculentum Mill., cv. ‘Jinpeng 10’) growth, yield and water use 〖JP3〗efficiency. Three levels of irrigation (W1: 100%ET0; W2: 75%ET0; W3: 50%ET0) and three fertilization〖JP〗 levels (F1: N 240-P2O5 120-K2O 150 kg/hm2; F2: N 180-P2O5 90-K2O 1125 kg/hm2; F3: N 120-P2O5 60-K2O 75 kg/hm2) were combined with three replications of fertigation. There was no significant effect factor on plant height and stem diameter of the interaction of irrigation and fertilization, but the stem diameter was significantly higher at W1F1 treatment, and there was a positive correlation between fertilization rate and stem diameter. The F2 treatment had the highest leaf extension rate, while the fertilization rate had significant effect on leaf extension rate, and the sensitivity of the fertilization was greater than that of the irrigation treatment. There was an important impact of the fertilization rate on dry matter accumulation, but the irrigation level did not follow this trend. The influence of fertilization on dry matter accumulation was greater than that of irrigation. The interaction of irrigation and fertilization had significant effect on root shoot ratio, and the F2 treatment had the highest average root shoot ratio compared with F1 and F3 treatments. The single factors of irrigation or fertilization significantly affected the tomato yield and water use efficiency, and the interaction of fertilization and irrigation had a great significant effect on the yield. The average tomato yield in W1 was 5.99%, 13.54% higher than those in W2, W3 treatments in 2012. Tomato fruit number was positively related to tomato yield, but the single fruit weight had no correlation with fruit yield. The crop water consumption was positively related to irrigation amount, and there was no significant trend between fertilization rate and crop water consumption, while fertilization rate had an obvious promoting effect on crop water consumption. According to the field experimental and comprehensive consideration of tomato yield and water use efficiency, the recommended irrigation amount was ranged from 151.12mm to 207.76 mm, and 〖JP2〗fertilization rate was ranged from 453.58kg/hm2 to 461.08 kg/hm2(upper limit: 〖JP3〗N 21345-P2O5 10672-K2O 133.41 kg/hm2; lower limit: N 21698-P2O5 10849-K2O 135.61 kg/hm2).

Abstract:On the basis of Penman-Monteith formula, the doublefactor combination experiments were designed, and the factors included certain gradients of the irrigation quotas and irrigation frequencies. Through consecutive 3year investigations concerning field experiments of cotton under conditions of mulched drip irrigation with nowinter and spring irrigation (NWSI) from 2012 to 2014, the rules for changes in soil salt content were determined, and the effects of these changes on cotton yield were analyzed. The results showed that during the growth period of cotton, soil salt content within soil layer depths of 0~30cm was more conspicuous than that within soil layer depths of 40~100cm,smaller irrigation quotas and less irrigation frequency brought about increased magnitudes of changes within soil layer depths of 0~30cm, and such changes became the most salient at seedling stage as well as blossing and bollforming stages. Effects of irrigation quotas on salt content in soil profiles were weaker than such effects exerted by irrigation frequencies. Enhancement of irrigation quotas was beneficial for reductions of salt content within soil layer depths of 0~30cm at different stages of cottons growth. Salt content in soil profiles exhibited a “C”shaped distribution: within soil layer depths of 0~40cm, salt content was 1.74% greater under 12 irrigations than that under 16 irrigations; within soil layer depths of 50~80cm, salt content was 1.71% higher under 16 irrigations than that under 12 irrigations; whereas within soil layer depths of 90~100cm, irrigation frequency exerted insignificant effects on salt content. Under the same irrigation frequency, the maximum seed cotton yield occurred under the irrigation quota of 460mm. Under favorable irrigation quotas, seed cotton yield was greater under 16 irrigations than that under 12 irrigations. Irrigation water use efficiency (IWUE) was enhanced under lowered irrigation quotas and increased irrigation frequencies, and in South Xinjiang afflicted by water deficit, the maximum IWUE can be acquired under high irrigation frequencies and low irrigation quotas. Within soil layer depths of 0~30cm, when initial soil salt content amounted to 2.03g/kg (less than 3.0g/kg), during the growth period of cotton, an irrigation quota of 460mm with 16 irrigations did not lead to the situation of soil salt accumulation. Therefore, it can be regarded as a suitable irrigation scheduling for NWSI in arid regions in South Xinjiang.

Abstract:As a new type of watersaving polymer materials, aquasorb can ameliorate soil structure, facilitate formation of soil aggregate, enhance water holding capacity of soil, adjust plant rhizosphere environment，reduce the loss of soil nutrients and promote crop growth. In the experiment, microcrystalline cellulose aquasorb and straw residue aquasorb were synthesized using by orthogonal optimization. In the process, acrylic acid was employed as graft monomer, potassium persulfate (KSP) as initiator, and N,N′methylene bisacrylamide (NMBA) as crosslinking agent. The the max water absorbency of two aquasorbs (microcrystalline cellulose aquasorb and straw residue aquasorb) were 401.20g/g and 382.22g/g, respectively. In this paper, the effects of these two kinds of cellulose aquasorbs on the physicochemical properties of the substrate and growth physiological indexes of cucumber seedlings such as roots activity, seedling index and G value (the growth rate of the daily average dry mass) etc. were compared. The results indicate that after the addition of two cellulose aquasorbs in plug seedling, there are significant effects on promoting soil physicochemical properties and the growth of cucumber seedlings. After 36 days, when the mass fraction of microcrystalline cellulose aquasorb is 0.3%, the G value, seedling index and root activity of cucumber seedlings samples can reach (0.0154±0.0009)g/d, 0.4892±0.0762 and 61.82μg/(g·h), respectively. When the mass fraction of added straw residue aquasorb is 0.3%, the G value, seedling index and root activity of cucumber seedlings samples can reach (0.0156±0.0004) g/d, 0.5089±0.0985, 60.90μg/(g·h), respectively. The research results show that straw residue aquasorb can be used as a new type soil aquasorb applied in field production.

Abstract:Understanding of ecological demanding condition is conducive to analyze the supply and demanding relationship of ecosystem services and optimize land resource layout and ecological land configuration. The research was carried out from the perspective of ecosystem services demanding. Three factors were selected as evaluation indicators, including ecology economy harmony, ecological scarcity and human development. Based on the evaluation of these three separated indicators, the overall ecological demanding in Beijing City was evaluated by multicondition evaluation method, and the Beijing City was divided in to three ecoregions. The results of each indicator show that there are significant differences in ecosystem services value per capita between different districts of Beijing City. Moreover, the ecological resources become increasingly scarce from central districts to suburban districts. In the aspect of ecology economy harmony, most mild coordinated regions distribute in the ecological conservation areas which locate in the north of Beijing City, the capital core functional areas and new urban development areas are mostly on the mild conflicting level. Human development and ecological demanding gradually reduces from the downtown to the outer suburbs. The overall evaluation result presents that the ecological demanding gradually reduces from city center to outer suburbs. More specifically, the Dongcheng District, Xicheng District, Chaoyang District and Fengtai District are at high levels, Yanqing District, Miyun District and Pinggu District are at low levels, and other districts are at moderate levels. According to the characteristics of different ecoregions, the suggestions about ecological environment construction were proposed. The study of this paper can provide references for the planning and adjustment of regional land resource, deployment of ecological land and environmental protection.

Abstract:The production of high quality renewable hydrocarbon fuels through catalytic pyrolysis of waste vegetable oil and polyethylene with the ZrO2/Al2O3/TiO2 polycrystalline ceramic foam as catalyst in the high-pressure reaction kettle was carried out. The effects of reaction temperature, time, catalyst amount and material feeding ratio were investigated on the production of renewable hydrocarbon fuels through catalytic pyrolysis of waste vegetable oil and polyethylene. The optimal condition was achieved that the reaction temperature was 430℃, the reaction time was 40min, the dosage of the catalyst was 15%, the quality ratio of waste vegetable oil and waste polyethylene plastic was 1∶1, and liquid product yield was 65.9%. The GC-MS analysis indicated saturated hydrocarbon percentage of TIC peak areas in pyrolysis liquid product was close to 100%, 97.85% of which were straight-chain alkanes. The pyrolysis gas and liquid products were precisely analyzed to deduce co-pyrolysis with ZrO2/Al2O3/TiO2 polycrystalline ceramic foam catalyst mechanism. Pyrolysis oil properties were determined. Compared with biodiesel and 0# diesel, pyrolysis oil heat value was higher, and the density and viscosity were similar to 0# diesel. Freezing point and cold filter plugging point were better than those of biodiesel. The low temperature fluidity was good. It proved the feasibility to derive renewable hydrocarbon fuel from copyrolysis of waste vegetable oil and waste polyethylene plastics with ZrO2/Al2O3/TiO2 polycrystalline ceramic foam catalyst.

Abstract:The particle size distribution, chemical composition, microstructure, thermogravimetric behavior and the slagging and fouling characteristics of the peanut shell ash (PSA) and corncob ash (CCA) prepared by ashing at 600℃ and 815℃ were comprehensively studied by using techniques like laser particle size analyzer (LPSA), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and thermal gravimetric\|differential thermal analysis (TG-DTA). It was presented that ashing temperature had a remarkable effect on the properties. Whereas, it had no obvious effects on the slagging and fouling characteristics. Both the granularity and the total weight loss decreased with the increase of ashing temperature. The contents of K, Na and Cl gradually reduced with the increase of ashing temperature. However, the contents of Si and Ca had no obvious variation. The 600℃ PSA still maintained the original skeleton of peanut shell biomass. The broken degree of 815℃ PSA was much more serious than that of 600℃ PSA. A small amount of SiO2 crystal was found in 815℃ PSA. For CCA, there was an obvious fusion phenomenon in the 600℃ ash while the 815℃ ash presented serious slagging characteristics. For 600℃ biomass ashes, the main weight loss occurred within 300~600℃ and the differential thermal curve showed an intense exothermic peak in this temperature range. It indicated that the soften or melt process of ash was accompanied with the exothermic reaction. For 815℃ CCA, the weight loss between 600~800℃ was considered to be caused by the volatilization of lively alkali metal chloride as well as the decomposition of unstable carbonates when under high temperature.

Abstract:Cheese is a high nutritional dairy product which is rich in protein and calcium. Moreover, cheese is the dietetic mainbody in developed countries, as well as the research hotspot of dairy science. Cheese texture and flavor characteristics are the aggregative indicators of cheese quality. How to improve the texture and flavor of cheese and analyze its forming mechanism are always the emphasis and difficulty of cheese research. By analyzing the steps such as the quality of raw milk, the processing of coagulation, ripening, brining, stretching and concentrating, as well as the processing technology of low fat and low salt cheese, the article comprehensively reveals the key impact factors of the texture and flavor characteristics of cheese. In addition, the article reviews the key mature control technology of cheese processing, such as the regulation of coagulation methods, the use of the adjunct cultures to accelerate the formation of the cheese characteristic flavor, and the genetic modification technology to accelerate the ripening of cheese, etc. Moreover, the article puts forward the research direction of the development of cheese, such as the regulation of calcium to precisely control the curds texture, as well as the effect of somatic cells on the texture and flavor of cheese, and so on. In conclusion, the article aims to provide a reference for quality improvement and industrialization of cheese in China.

Abstract:The inherent content of calcium in milk powder was rapidly determined by using the nonlinear chemical fingerprint method. Firstly, the inherent calcium content in three brands of milk powder was determined by using flame atomic absorption spectrometry as described by GB 5413.21—2010 (National Standards of PR China). Different contents of calcium carbonate were added into the above three brands of milk powder, respectively. Using“H+Mn2++BrO-3+acetone+substrates in milk powder” as reaction system, the nonlinear chemical fingerprints of milk powder with different calcium contents were obtained, and there was a linear relationship between the undulatory period and the total content of calcium in milk powder, where the total content of calcium consisted of the inherent calcium content in milk powder and the calcium content of being added into milk powder. Then, the inherent content of calcium in milk powder was calculated by using the least square method. The results showed that the total content of calcium in milk powder and the undulatory period value had a good linear relationship within 0.0227～0.0323g range of the total content of calcium when the total amount of milk powder was 0.9g, the determination coefficient was 0.9953～0.9988, the recovery rate was 99.18%～101.60%, the RSD was 0.47%～1.63%, and the determination range of the inherent calcium content in milk powder was 0～0.0323g. The method developed has advantages of good accuracy and simple operation, and it is a practical and feasible method for determining the inherent calcium content in milk powder. In addition, the method can be used for reference in research on the methods for the determination of other components in other complex samples.

Abstract:Spoilage spawned by Zygosaccharomyces rouxii can cause sensory defect in apple juice, which could hardly be perceived at the early stage and therefore would lead to the serious economic loss. Thus, it is essential to detect the contamination earliest to avoid costly waste of products or recalls.The present work tried to explore the feasibility of detection of the spoilage in apple juice caused by Zygosaccharomyces rouxii (Z.rouxii) at early stage through determination of flavor of apple juice by using electronic nose (EN). The ability of EN to discriminate apple juices with different contamination time was analyzed by using linear discrimination analysis (LDA) method. The contribution of each sensor to the diagnosis of the Z. rouxii\|contaminated apple juice by EN was studied using loadings analysis. Test panel evaluation was performed as a reference to validate the performance of EN technique.The correlation between electronic nose signals and yeast concentration was analyzed by partial least squares analysis (PLS) method. The results showed that EN was able to accurately identify the Z.rouxii\|contaminated apple juice after incubation for 12 h,corresponding to the fungal number of less than 200 CFU/mL, the level at which the test panel could not yet identify the spoilage.Loadings analysis indicated that sensors S1, S2, S6, S7 and S8 had the most important effect on identification of apple juice contaminated at different levels.A good correlation between sensors response signals and yeast concentration was revealed by PLS algorithm,with correlation coefficient R2 of 0.97 and 0.93 in calibration model and prediction model, respectively. The standard error of calibration and standard error of prediction were 0.28 and 0.26, respectively.These results indicate that it is feasible to detect the spoilage in apple juice caused by Z. rouxii at early stage using electronic nose, and this sensory technique is expected to be applied widely in the field of detection of foodborne microorganisms.

Abstract:This study selected total acid content and pH value as characterization indicators and used hyperspectral imaging technology and chemometric methods to discriminate uniformity of Zhenjiang balsamic vinegar grains. First, hyperspectral transmission images in 432~960nm of vinegar grains, total acid content and pH value were acquired. Secondly, PLS and LS-SVM method were used to establish uniformity indicators content prediction models after preferred variables which were selected by GA and siPLS. The root mean square error of prediction (RMSEP) and correlation coefficient (R) for the test set are 0.389% and 0.7751 for total acid content, 0.0417 and 0.7974 for pH value. Total acid content and pH value in each pixel point on the vinegar grains were obtained by the above prediction models. After pseudo-color processing, the distribution map of total acid content content and pH value before and after turning up the vinegar grains were obtained. In the distribution maps, the range of total acid content and pH value in the grain were 3.0% to 7.8%, 3.5 to 4.2 before the overturning, and 4.8%~7.0%, 3.6~3.9 after the overturning. By overturning the grains, the degree of uniformity was improved while high local concentrations phenomenon still exists. The overall results revealed that hyperspectral imaging technology is a promising technique to discriminate the degree of uniformity of grains after overturning rapidly and nondestructively.

Abstract:Potato is an indispensable food crop for the people in the world. As a kind of light injury on the surface of potato，slight bruise of potato cannot be accurately tested when potato placed in random orientation. This paper proposed a method by combining hyperspectral image based on Vshaped plane mirror with fruit fly optimization algorithm (FOA) to identify slight bruise of potato randomly placed. In this study, hyperspectral imaging system was built based on Vshaped plane mirror and 322 potato samples were bought as the research subjects. To meet with the practical production, within half an hour after bruise occurred, potatoes were placed in three positions: the damage part facing to camera, side to camera, and back to camera. Then hyperspectral images of all potatoes were collected including reflection image F1 in mirror 1, image F2 directly obtained by camera and reflection image F3 in mirror 2. Average spectrums from these three images were spliced into attribute matrix of sample. Support vector classifier(SVC) model was established in full bands after utilizing standard normal variate(SNV) and the recognition accuracy of prediction set was only 8411%. Variable selection was processed by ant colony optimization(ACO). Nine spectral variables (762nm, 879nm in F1; 711nm, 957nm, 1020nm in F2; 510nm, 746nm, 1.000nm, 1.007nm in F3 )were selected and the recognition rate reached 95.32%. FOA, genetic algorithm(GA) and grid search were respectively applied to search the best penalty parameter c and kernel function parameter g. By comparing results of those models, FOA obtained optimal parameters(c=11.0763，g=9.2625). FOA-SVC was proved to be the best model and the training set and prediction set recognition accuracy both reached 100%. The results show that the combination of hyperspectral image based on Vshaped plane mirror with FOA-SVC could accurately detect the slight bruise of potato.

Abstract:Soluble solids content (SSC) and blackheart are main quality evaluation indexes and physiological disease for ‘Yali’ pear, respectively. The feasibility of simultaneous and online detection of blackheart and SSC was investigated by using visiblenear infrared (NIR) diffuse transmittance spectroscopy. The visibleNIR energy spectra of blackheart and healthy ‘Yali’ pears were collected at the speed of five samples per second. The response properties of visibleNIR spectra for blackheart and healthy ‘Yali’ pears were analyzed, and the discrimination models of peak ration (PA) with wavelengths of 674nm and 634nm and the discrimination partial least square (DPLS) were developed for discrimination of blackheart and healthy pears. DPLS was superior to PA with relative higher classification rate of 100%. The influence of blackheart to SSC determination was also explored by using partial least square (PLS) regression models, and PLS model was employed with healthy ‘Yali’ pear samples. Then a novel strategy was proposed for simultaneous and online detection of blackheart and SSC for ‘Yali’ pears. With this strategy the blackheart pears were removed and healthy pears were sorted by SSC values simultaneously in the sorting line. The new samples were applied to evaluate precision of online sorting of blackheart and SSC for ‘Yali’ pear, which were not used to develop calibration models. The classification rate was 100% for identifying blackheart pears, stand error of prediction (SEP) was 0.45°Brix, and accuracy of sorting for healthy pears was 98%. The results suggest that diffuse transmittance visibleNIR technique combining with DPLS and PLS methods has significant potential to simultaneous and online detection of blackheart and SSC of ‘Yali’ pears; moreover, it may have commercial and regulatory potential to avoid time consuming work, costly and laborious chemical analysis for ‘Yali’ pears trade.

Abstract:A new method was studied to detect pesticide residues in lettuce leaves rapidly, accurately and nondestructively. In this paper, four groups of lettuce were used as experimental samples, the first group was sprayed with acetone, the second group contained dimethoate (volume ratio between omethoate and acetone is 1∶1000), the third group contained dimethoate (volume ratio between omethoate and acetone is 1∶500), the last group of lettuce leaves dimethoate (volume ratio between omethoate and acetone is 1∶100). Totally 384 samples of four varieties were scanned by using the NIR hyperspectral imaging system (871.61~1766.32nm). The region of interest (ROI) in hyperspectral image of samples was selected, and the mean spectra of all pixels in the region of interest was calculated. At the same time, optimal image selection was carried out by principal component analysis (PCA). The first principal component (PC1) image and the second principal component (PC2) image were used for texture features analysis. Among the processing of spectral data, successive projections algorithm (SPA) and principal component analysis (PCA) were used to obtain characteristic wavelengths. Finally, Knearest neighbors (KNN), Mahalanobis distance(MD), Fisher linear discriminate analysis (FLDA) algorithm were used for model establishments respectively based on spectral feature and the combined features in full and characteristic wavelength. In all models, the performance of FLDA based on the combination of texture and spectral features by SPA has its superiority in classification recognition with the training rate of 98.90% and prediction rate of 100%. The results show that it is feasible that NIR hyperspectral image with data fusion is used to discriminate the grade of pesticide residue.

Abstract:Modified atmosphere techniques and preservation technologies, coupling with coldchain have been approved themselves as key tools to prevent spoilage and prolong shelflife for the fruit storage and transportation. Taking table grape as example, modified atmosphere techniques create gaseous microenvironments which usually consist of reduced O2, elevated CO2 concentrations compared to air and fresh keeping agent of sulfur dioxide which commonly used to release SO2 and strongly retard the growth of these pathogenic fungis. Thus, there is an increasing concern about gas monitoring to improve the transparency and traceability during coldchain. However, the existed industrial gas sensor can not meet the demand of coldchain logistics in scale and precision. Then, the paper aimed to extract the static and dynamic response characteristics of gas sensors for table grape cold-chain logistics, which developed the method of characteristic parameter extraction based on time domain, and the carbon dioxide, oxygen and sulfur dioxide were developed as basic parameters. The method of linear regression was used to optimize characteristics of gas sensors, so the best feature parameters were got for gas sensing signal, which contain the response of gas sensor in the air, steady response of gas sensor, the speed of response and response recovery, time of response and response recovery, and response integrated signal respectively. The best feature parameters can be used to analyze the characteristics of gas sensing signal which has a cumulative effect on the quality in coldchain. It is possible to improve the application and monitoring precision, monitoring sensitivity and monitoring stability of gas sensor in the coldchain logistics further more.

Abstract:The processing characteristics of soybean milk were directly affected by properties of protein particles. The formation of protein particles in soybean milk was closely related to heating temperature and heating method. At present, micropressure boiling has become a kind of important method of cooking soybean milk in China. However, up to now there were no reports on the influence of micropressure boiling on the changes of soybean milk processing characteristics. Through the contrast and analysis of the changes in the content of protein particles in soybean milk between ordinary pressure boiling and micropressure boiling, this article studied the effects of the micropressure boiling method on the stability of soybean milk, rheological properties and the textural characteristics of soybean curd. The experimental results showed that micropressure boiling method changed the composition of protein particles in soybean milk, after boiling for 10 min, the content of protein particles in soybean milk would reach 52%, which was 13% higher than that in ordinary pressure boiling, and as a result, there were significant changes of soybean milk processing characteristics. Soybean milk after micropressure boiling would possess particles with much smaller average diameter (0。3257μm after 10min boiling), which was beneficial for the stability of soybean milk in longterm storage. Fluid properties indexes of micropressure boiling soybean milk and ordinary pressure boiling soybean milk were both approximate to 1, showing Newtonian fluid properties. But as protein particle numbers increasing after micropressure boiling, there were more acidic peptides and α and α′ subunit in 7S distributing in the surface of protein particles, which improved protein hydrophilicity and increased the viscosity of soybean milk. In the gelation process of soybean curd, more protein particles were involved in the formation of network structure, which made the network structure more compact, thus enhanced the interaction between proteins, as a result, the hardness, elasticity and glue viscosity of soybean curd gel were all increased, and the gel texture of soybean curd was significantly improved.

Abstract:With the rapid development of computer technology, its possible to process multitype and mass data realtimely. In order to achieve realtime monitoring and early warning in laying hen raise, a system based on a distributed streaming computing framework “DataCanal” was developed. DataCanal is a data flow oriented distributed computing framework with the control flow and data flow dispersion model, which using the distributed file system as the storage of intermediate result, supporting realtime acquisition and processing multiple remote data sources. DataCanal is the basic facility of the system, which ensures the extend and realtime processing of system. The system was developed in Browser/Server mode. The users can access the system through the browser, which improves the convenience of informatization sharing. The system realizes realtime data acquisition and display, production information management, early warning, decision analysis, and system management functions. The result shows that the system solves the problem of information and realtime processing of mass data in laying hens raise. In the case of eight machines, the highest throughput of DataCanal cluster reaches 160MB/s, and the delay is at the minute level. In the online experiment, the DataCanal cluster processeed about 25GB of data every day. The maintenance and upgrade of system are convenient. Further research will be done on the mobile client.

Abstract:To struggle with the problems of hard to acquire the optimum light value for tomato planting rapidly and precisely, a model was developed to control the light staying around the optimum value in the environment. In order to evaluate the optimum light saturation points under different temperatures, a novel light and temperature coupling optimizing method based on improved fish swarm algorithm was proposed. This new method effectively improved the optimum speed of traditional fish swarm algorithm through adjusting the vision and step dynamically. In addition, the method could avoid trapping into local optimum, and get more accurate optimal solution than genetic algorithm. Based on the light saturation points by optimizing this method, the light environment regulation target model was established with nonlinear regression. For verifying the accuracy of the method, a set of light and temperature coupling photosynthetic rate test was performed. The results showed that the model determination coefficient can reach 0.9999, the squared error term was 1543, and the root mean square error was 0.712. A comparison between simulation results and testing results was made, which showed the highly linear correlate relation with a value of 0.988 between them. In addition, the maximum relative error was less than ±2%, which is obviously better than the results of genetic algorithm. At last, a positive conclusion was obtained that the proposed light and temperature coupling optimizing method in this study can acquire the optimum light saturation points rapidly and dynamically, and has great significance to the precise control of light environment in facility.

Abstract:The dangerous body movements(DBM) of lactating sows, such as the change from standing, sitting to lying, is a major cause for the death of pre-weaning piglets. Although, the utilities of farrowing crate and anti-crushing rail will effectively reduce the mortality caused by the DBM of lactating sows, there are still significant differences for the mortality of piglets in the same breeding environment, therefore, the difference maternal ability of individual sow will play an important role. The maternal index of sow was determined by the changing frequencies and types of these DBM. Five lactating sows of Xiao Meishan which were bred in the farm of Jiangsu Polytechnic College of Agriculture and Forestry were used in this study. Firstly, a set of monitoring node with MPU6050 and bluetooth module was tighten on the neck of a sow to collect the three-axis acceleration data during 10 d. Then, the histogram method was used to compute the threshold of the kinetic energy in order to locate the area of a DBM quickly. Finally, a classifier to identify the type of the DBM was built according to the characteristics of the body postures occurred in pre- or pro-DBM. The results showed that the accuracy of for marking DBM area for 327 samples was 77.4%,while the accuracy of DBM recognition was 81.7%. The main reason for the different accuracy mentioned above is that the errors caused by piglet crashing the node were corrected by the recognition algorithm of posture. Thus, the bend index of a lactating sow can be calculated further more and the data basis for the scientific evaluation of maternal ability in the breeding sow will be provided.

Abstract:Dissolved oxygen affects the growth status of fishes directly in aquaculture, so a prediction model to determine the future changing trend of dissolved oxygen was set up. When the predicted values of dissolved oxygen were below the safety value, the farmer can start oxygen increasing machine in advance to maintain the safety of fishes. The proposed dissolved oxygen prediction model was based on the least squares support vector regression (LSSVR) model with chaotic mutation to improve the estimation of distribution algorithm (CMEDA) to find optimal parameters (γ and σ) of LSSVR. Because these two parameters can significantly affect the performance of LSSVR, the other three parameter optimization methods, that means, particle swarm optimization (PSO) algorithm, genetic algorithm (GA) and the traditional LSSVR, were used to compare with CMEDA algorithm. The mean absolute percentage errors of the prediction results of four models were 0.32%, 1.27%, 1.98% and 2.56%, respectively. The CMEDA-LSSVR model has a higher prediction accuracy and more reliable performance than the other models. In order to make farmers use prediction model conveniently, a dissolved oxygen prediction system GUI based on Matlab was designed. Farmers download the history data from remote monitoring system by web browser as training data and testing data，the prediction results of different time would be calculated and displayed on the GUI. The prediction model was used in Yangzhong, Jiangsu Province, China, and it performed well. It helps farmer to make decision and reduce aquaculture risks.

Abstract:Compared with the traditional field information collection, field information collection with mobile terminal has strong flexibility, easy collection and other advantages, and has become one of the main means of agricultural field data acquisition. But when the field information was collected, data synchronization has disadvantages of slow sync frequency, unnecessary retransmission of data, and serverside changes, which can not synchronize to the mobile terminal timely. The grammar and data synchronization process of the Sync ML protocol was lucubrated, the data synchronization process of mobile data acquisition was analyzed and various problems were encountered. Sync ML protocol was improved, slow synchronization strategy was proposed, and active push synchronization strategy and change data capture strategy were designed. The strategy of combining pull synchronous with push synchronous was designed, the push synchronous was used to push synchronous messages, and the pull synchronous was used to synchronize the data from server. The data synchronization strategy middleware was designed and implemented. Mobile terminal based on Android and C# technology was used. The middleware was used in information acquisition system and ricepositioningtestscore system. The results showed it significantly improved the efficiency of data synchronization and reduced the unnecessary retransmission of data. It makes the field information collection system in favor of the promotion of modern information agriculture, and enhances the work efficiency of field data acquisition and data accuracy. The experimental results verify that the middleware has high practicability and universality, and makes data transmission not increase as the number of the synchronization.

Abstract:Fractional vegetation cover (FVC) is one of key indicators for the change of ecological environment. Estimation and analysis on regional FVC is of great significance for local government. In this paper, remote sensing technology was used to study FVC, and spatialtemporal FVC variation was analyzed from 1988 to 2013. Five periods of Landsat series remotely sensed data acquired in 1988, 1994, 2003, 2010 and 2013 were used to estimate the FVC based on topographyadjusted vegetation index (TAVI). TAVI can effectively eliminate the discrepancy between the shady and sunny slopes, and FVC calculated from TAVI can improve the estimation accuracy of the shady slopes. The vegetation coverage from 1988 to 2003 was generally well. The area percentage of FVC values which are larger than 06, were more than 65%, lying in the surrounding areas of the county. In most of the west and the north area, the FVC was larger than 08. The area percentage of FVC values less than 04 was less than 15%, mainly lying in the middle area along the Tingjiang River, which are also the most serious towns of soil erosion area. The worst FVC value occurred in 1994, which was decreased from 1988 and distributed in most of the towns, due to the serious frost occurred in the winter of the end of 1993 and the beginning of 1994. From 1994, the vegetation coverage was improved, and in 2003, the vegetation coverage recovered the level of that in 1988. From 2003 to 2013, the FVC was improved remarkably and most of the barren lands in the middle area are now covered with vegetation. The vegetation coverage has greatly been improved in the middle serious soil erosion towns particularly. The FVC changes are closely related to investment intensity for the control of soil erosion performed which was leaded by the local government. Due to the great efforts for treatment of soil erosion from 2000, a notable increase of FVC occurred from 2003 to 2013.

Abstract:Land use classification plays an important role in adjusting land structure and developing land resources reasonably, especially in the farming area. The objective of this research is to choose an appropriate method to classify land use type in the farming area. A new classification method, random forest (RF) classifier, was applied to make land use mapping in agricultural cultivation region with multisource information, including multiseasonal spectrum, texture and topographic information. The best classification scheme was chosen to extract land use information, and RF algorithm was used to reduce the dimension of characteristics variables. The RF algorithm, support vector machine, and maximum likelihood classification were used to map agricultural land use, and the applicability of these three different classification methods was analyzed. The result shows that RF classification of land use classification with multisource information effects best, the overall accuracy and Kappa coefficient are 85.54% and 0.8359 respectively. Feature selection method from RF algorithm can effectively reduce the data dimension and ensure the accuracy of classification at the same time. Compared with these three classification methods, RF algorithm performs the highest overall accuracy of 81.08%, which is respectively 9.46% and 5.27% higher than support vector machine and maximum likelihood classification. It is an effective scheme that makes land use classification in the farming area using RF classifier with multi-source information. It provides a fast and feasible method for the division of land use types.

Abstract:Airborne LiDAR can obtain threedimensional structural information of trees and get forest information by using points cloud classification and calculation method of crown projection area and volume. From the distribution of points cloud，the laser pulse formed an once echo when encountered the bare ground and roof of the building, and the distribution of the generated points cloud were smooth and continuous. The laser pulse penetrated vegetation would appear multiple echoes, the distribution rules of the points would be destroyed, and the distribution was in an irregular shape such as clusterlike. First, the points cloud of ground were extracted by using triangulated irregular network, then the points cloud of building were extracted by using planarfitting filtering algorithm. The points cloud of building were filtered to get points cloud of forest, and then the points cloud of forest were projected onto x-y plane. The edges of points cloud of timber were extracted by using the angle method; its corresponding image was displayed; the area of polygon was calculated by using area algorithm; then the calculation of the projection area of crown was achieved. In the study area, 10 experimental districts were randomly selected to carry out the traditional manual measurement. The experimental results showed that the projection area and volumes correlation coefficient of the two measurement methods were 0.957 and 0.944, respectively. The proposed method was feasible to achieve the accurate extraction of forest information rapidly and efficiently which includes a wide range of tree crown projection area and crown volume.

Abstract:Water plays an important role in various physiological activities of plants. Measuring plant stem water content in real time without damage has important guiding significance for studying the life activities of plants. A kind of stem water content of realtime and nondamage online detection method based on standing wave ratio was introduced in detail. BD-IV stem water content sensor was designed based on the method. With organic solvents and the beakers as the simulation environment, pine as the experimental materials of the section of tree, and peach as experimental materials of standing tree, the detection performance of BD-IV stem water content sensor was verified. BD-IV stem water content sensor can accurately detect volume water content under the conditions of plant stem diameter between 5.0cm and 10.5cm, volume water content between 1.17% and 59.59%. Through the longterm monitoring of daily and monthly changing rule of stem water content of peach, the result measured by BD-IV stem water content sensor was consistent with plant physiological characteristics. Through the longterm monitoring of stem water content and stem sap flow of willow by using BD-IV stem water content sensor and SF-L stem flow gauge made in Germany, the relationship between stem water content and stem sap flow was summarized. It provides a localization testing instruments with high performance to price ratio for the research on plant physiological characteristics.

Abstract:Stem water content and sap flow rate are regarded as two important parameters associated with water transport through plant stem. Gamma-ray instruments, although often highly accurate and noninvasive, carried a potential risk of radiation exposure restricting their applications. The MRI method is noninvasive and safe, but it is costly and impractical for long-term monitoring of plant water status in natural circumstances. Generally TDR and FD sensors are often regarded as invasive methods because both techniques are depended on inserting two or more waveguide lines into the stem, causing some tissue damages in the stem. For this purpose, a novel sensor was presented based on the inner fringing field of capacitor. The sensor comprises a pair of metallic electrodes designed to wrap around stems likes an upper and a lower strapring. The strap-rings were connected to a high frequency oscillator operating at 100MHz. Because the dielectric property of stems is closely correlated with the amount of water in the stem, stem water content can be measured without causing stem tissue damage. To verify its technical performance, firstly, three different physical tests were conducted in the laboratory. The results confirmed that both sensitivity and linearity of the sensor were satisfactory. Then these sensors were tested with three potted apple trees grown in a greenhouse. By using the proposed technique, the actual water recharge and discharge occurred between the stem tissues and the water pipes in the stem were successfully observed. Furthermore, the turgor breakdown and recovering process were observed when these apple tree samples suffered from water deficit. In general, all measured data were clearly interpretable to the known knowledge of plant water relation

Abstract:With the analysis of domestic and abroad present situation of forest protection and fire monitoring, based on the Iridium SBD communication services and support vector machine algorithm, an information collecting and data analyzing system for forest management and protection was designed, which was able to collect concentration of carbon monoxide, carbon dioxide, smoke air temperature and air humidity automatically, transfer the wireless remotely in anywhere of forest, and recognize forest fire probability effectively in a certain range. The hardware of monitoring terminal consisted of STM32 CPU, Iridium Q9602 module, LTC2950-1, DS2781 and twostage power voltage step down system. The software made the terminal be able to collect and transfer on automatic mode or manual mode, analyze data and recognize fire probability on the remote server. It was proved by experiment that the system could collect five microenvironment parameters, transfer data by using Iridium with the success rate of 100% and recognize fire probability above the rate of 80%. The system had been applied and tested in the forest fire work of Hailar District, Hulunbeier, Inner Mongolia Province. It can improve the monitoring mechanism of the patrol personnel and the efficiency of forest resources survey.

Abstract:In order to solve the difficult acquisition of plants’ 3-D point cloud data, the Kinect was adopted to collect the 3D point cloud data of corn. Compared with the usual 3D scanning equipment, Kinect can rapidly and efficiently acquire the data with lower cost. But the accuracy of data acquired by Kinect is low. It is valuable to denoise the data. According to the characteristics of the point cloud data acquired by Kinect, the data were preprocessed and smoothed. In this paper, a multi frame data fusion method was used to obtain more complete plant 3D point cloud data, and it played a role in smoothing. A denoising algorithm based on density analysis and depth data bilateral filtering methods were proposed to process the outlier noise and internal highfrequency noise. In the experiment of corn and eggplant internal high-frequency noise denoising, compared with the traditional bilateral filtering, the denoising time of the algorithm in this paper was only 2.71% and 1.78% of traditional bilateral filtering and the noise was well removed by adjusting the parameters. The experimental results show that the proposed method can easily and quickly remove the noise of different scales, while preserving the integrity of edge data. Consequently, the good 3-D point cloud data of the plant could be obtained.

Abstract:Electromagnetic valve train (EMVT) in camless engine offers large potential for both part load fuel economy and high load engine torque. However, the temperature rise of EMVT at the high engine speed and full load is serious because of its large power density, which barricades the development of EMVT. According to the structure characteristic and operating principle of moving coil electromagnetic valve train, a novel scheme based on pumping effect of moving coil was proposed to enhance the gas flow rate and flow velocity in air gap between the moving coil and permanent magnetics, and strengthen the effect of convective heat transfer without additional drivers. Based on the theoretical analysis of convective heat and mass transfer, the main influential factors of this temperature suppression scheme were got, which includes the gas flow and gas peak velocity in air gap. Numerical model of flow area was established to analyze the dynamic responses of annular throttleslice and gas flow status, then structure of the scheme was improved accordingly. Simulation results indicate that the improved scheme, of which the material of annular throttleslices is carbon fiber and its working stroke is 0.2mm, then the gas flow and peak velocity of each cycle have reached to the maximum about 1.21mg and 58.9m/s under typical condition, respectively. Finally the temperature tests of electromagnetic valve train were carried out under longtime operation, results show that the improved scheme has achieved a better efficiency to suppress the temperature of electromagnetic valve train, it has a significant drop about 12.1℃ in maximum for one measuring point under typical condition.

Abstract:The influence of injection duration on the mixture formation and combustion performance of high power multi\|injection gas engine was studied. CFD simulation was employed to study the different effects on the mixture formation by adopting the structures of single elbow and twin elbows individually. On the basis of the result, the twin elbows structure was determined to be used in the experiment. And five different periods of injection duration were particularly designed. CFD simulation and combustion analysis were employed to explore the influence of different injection durations on mixture formation and combustion performance under the conditions of engine working in rated power while other parameters remaining unchanged. In the experiment, the beginning time of each injection duration period was at 40° after inlet TDC. In this situation the exhaust valve was fully closed, natural gas couldn’t directly enter the valve. Moreover, with the quick movement of piston, the injection gas has strong disturbance energy. These all help to promote the combination of natural gas and air. The results of CFD simulation and experiment indicated that under the experimental conditions, when the injection duration extended from 5ms to 10ms, the cycle variation of combustion of the studied engine decreased obviously. That’s because the extended time could guarantee the disturbance energy which was produced by injection gas being fully used, therefore, the mixture formation quality was improved correspondingly. However, when the injection duration was prolonged to 12ms or 15ms, the flow rate of natural gas would be decreased and the injection gas couldn’t enter the cylinder. Thus part of natural gas still stayed in the elbow, which reduced the quantity of the gas that can effectively develop the mixture and make the mixture thinner, which was unfavorable for the combustion.

Abstract:Using air as the gas source, the regeneration system of exhaust gas recirculation (EGR) cooler was built to do an experimental study at 18℃, 60℃, 90℃, 120℃, 150℃, 200℃ and 300℃, which was based on nonthermal plasma (NTP) injection system. The influence of temperature on regeneration was investigated by measuring the volume fraction of main active substance (O3, NO2) and regeneration products (COx). The results indicate that CO and CO2 can be detected all the time, which means that the EGR cooler can be regenerated by airfed NTP at a wide temperature range of 18~300℃. In the process of regeneration, the volume fractions of O3 and NO2 show drop trends with the increasing temperature, and they are completely consumed when the temperature is 150℃. And the concentration of NOx decreases obviously firstly and then increases slightly with the rising temperature and gets a low level when temperature is above 90℃. Therefore, the temperature should be controlled at 150℃ in consideration of active substance utilization and NOx control. Additionally, little CO is produced, so that C1(the mass of C in CO) in C12 (the mass of C in COx) is less than 1/8. However, much CO2 is generated and remains relatively stable with the regeneration time. Besides, the trend of C2 (the mass of C in CO2) and C12 are almost same, they are all rising firstly and then dropping with the rising temperature, furthermore, they get the peak at 150℃. In total, the efficiency of main active substance which is generated by NTP reactor, is higher, the more carbon deposition is removed and the regenerative effect is more remarkable, when the regeneration temperature is 150℃.

Abstract:In a constant volume combustion chamber combined with high pressure common rail system, the ignition, combustion and soot formation characteristics of diesel were studied at different injection pressures keeping injection pulse width or fuel injection volume constant. The change range of injection pressure was 40~160MPa, which was commonly used in high pressure common rail diesel engine under middle and high loads. The experiments were conducted by using a highspeed photography technology and a combustion pressure acquisition system. The soot formation characteristic was studied by natural flame luminosity. Results show that, keeping injection pulse width or fuel injection volume the same, the test results have the same change trend: with the increase of injection pressure, the flame luminosity becomes weaker; the ignition region becomes larger; and the flame liftoff length becomes longer. In addition, the combustion pressure rise rate would increase. Also, the moment that pressure begins to rise and the moment that the maximum combustion pressure occurs are both advanced. At the same time, the heat release rate reaches peak more quickly and the peak value increases gradually. Keeping the volume of injected fuel unchanged, with the increase of injection pressure from 80MPa to 160MPa, the ignition delay is shortened from 1.7ms to 1.4ms; the combustion duration is shortened from 6.9ms to 4.7ms; and the soot formation is reduced significantly. However, such trend is weakened with the increase of the injection pressure.

Abstract:For the balance and controlling demand of the small and flexible delivery offshore floating platform, a 2-HUS/U parallel platform was presented and it had space twodimensional stable ability, which adopt ball screw mechanism. Its HUSlimps were regarded as the driver and Ulimp was regarded as the driven. It provided a guarantee for the fast and stable balance of platform, and the degree of freedom of the platform was verified by the screw theory. According to constraint equations of platform, the reverse solution and the Jacobian matrix of the platform was derived and its velocity，acceleration performance, and reachable workspace were analyzed. The whole dynamics of space parallel platform was analyzed by the Lagrange’s formulation. The results of kinematics and dynamics analyses of parallel platform were solved as numerical example. The results show that the control of stability and balance is easily achieved by platform of less freedom. The platform has the stable ability of threewave frequency of 10°/s, and meets the stable demand of threewave angle of 10°. The maximum tilt angle of platform is 12°, and the workspace is symmetrical about the center axis. In the wave angle 45° and wave frequency 10°/s, the driving force for load is 15000N, and the platform meets the high load need of offshore floating platform. Through the whole analysis, it proves the offshore platform proposed meets the demand of threewave environments, and it also proves certain theoretical basis for the platform optimization and control system design of such platforms.

Abstract:In order to make the global coupling characteristic researches of axial piston pump possible, this paper analyzed the configuration and the coupling situation between the subsystems, and then a bond graph modeling method based on array was proposed to develop the dynamical model of piston pump. The energy loss factor was defined which contains swash plate angle, contact length between the piston and the cylinder, piston pair and slipper pair friction coefficient. So the state space model of piston pump was obtained by the tribology and dynamics coupling mechanism analysis of pistonslipper subsystem. The dynamical equation parameters of the subsystem which contains nonlinear factors are integrated in the global coupling dynamical model of piston pump clearly and concisely. The simulation results show that the coupling between the ripple of flow and pressure and the fluctuation of speed and torque becomes more obvious under high pressure, and the fluctuation of speed will influence the ripple of flow and pressure seriously when its amplitude reaches a certain level. The simulation results of piston pump running state and efficiency variation are in agreement with the actual situation. So the global coupling dynamical model of piston pump is effective and correct. Compared with the traditional local model of piston pump based on the assumption of constant pressure or constant speed, the global coupling dynamical model of piston pump established in this paper can be used to investigate energy saving and noise reduction, fault diagnosis, volume control and nonlinear dynamics analysis realistically.

Abstract:To improve the precision of electro-hydraulic servo valve’s dynamic state character, a method was proposed by having the excitation signal integrated while calculated the servo valve’s frequency characteristic. In the measurement system, a programmable logic controller (PLC) controlled the cylinder’s displacement with a low frequency, while a displacement sensor detected the response signal with a high frequency, which would reduce the inherent error. The rest automatic operations were completed in the national instruments’ products (PXIe-1071, PXIe-8115 and PXIe-6251). In the software program, a LabVIEW produced control signal with a fixed value of sample and a change frequency, was sent to the PLC system, which would produce the final excitation signal. The valve’s displacement could be got, and the integration of the final excitation signal and the valve’s displacement signal were calculated. Finally, the servo valve’s dynamic state character could be got. At last, the MOOG D761-2716A servo valve’s test curve and the MOOG D661-1945E servo valve’s test curve were illustrated, which meet the correct results well. In the end, several conclusions were drawn: the method of having the excitation signal integrated can be used in the test of electrohydraulic servo valve and it can calculate the dynamic state value accurately. The composite measurement system (PLC+NI) can play a correct role in the test.

Abstract:The mixed highorder Fourier noncircular geardriven differential pump has some performance indexes such as discharge, flow pulsation and the maximum modulus of noncircular gear undercut which have many complex influential factors. In order to obtain the best parameters, the basic relations between the order of Fourier noncircular gear and parameters of vanes were established. The mixed highorder Fourier noncircular gear transmission model was built. The subobjective functions of displacement and flow pulsation, and the maximum modulus of noncircular gear undercut were presented. The target evaluation function using the efficacy coefficient method was put forward. And then the multiobjective optimization method was designed based on genetic algorithm to obtain noninferior solutions when the mixed highorder Fourier noncircular geardriven differential pump has the maximum capacity and the minimum pulsation rate which meets the requirement that the maximum modulus of noncircular gear undercut was more than 1.5 in the same pump cavity size. The flow pulsation rate of the optimized differential pump was 22.04% and the displacement was 3870.44mL. Thus, the flow pulsation rate was decreased by 11.3% and the displacement was increased by 3% compared with the existed study.

Abstract:To solve the high output press overshoot and low control accuracy problem existed in gasliquid press machine of single channel controlled mode, a gasliquid press machine equipped with dualchannel and dualaperture modes was designed based on the gasliquid pressure technology, while the speed of press was controlled by the bigger aperture channel and the accuracy was controlled by the smaller one. In order to study the dualchannel gasliquid press machines features, the gas mass flow model and boost process mechanical model were established on basis of gasliquid control system. For the sake of obtaining the cutoff pressure of auxiliary channel and the maximum deviation of output pressure, the models were simulated with different air pressures and various main channel orifice areas under Matlab/Simulink. The simulation results show that with the invariable cutoff pressure of auxiliary channel and the same main channel orifice area, the higher the air pressure goes, the greater the maximum deviation is; with the same air pressure, the smaller of main channel orifice areas size is, the smaller of maximum deviation is. To verify the feasibility of the cutoff pressure of auxiliary channel and the maximum deviation of output pressure, a testing platform was set up. The test result shows that the maximum deviation of output pressure is consistent with simulation result. The cutoff pressure of auxiliary channel from the simulation can be used as a basis for designing the dualchannel gasliquid press machine in practical applications.

Abstract:In order to make constant displacement pumps output multi-level constant flows and provide energy for several different pressure systems without a reducing valve, a double-stator multi-pump was successfully designed and tested, and the transmission theory was also presented. Taking the multi-pump and single-motor transmission system which consists of double-stator double-acting multi-pump and swash plate type axial piston motor for example, the influence of different volatilities of fluid output by multi-pump in different working ways on the motor output torque was analyzed. The results show that the effects of multi-pump on the system output characteristics were different in different working ways. When the inside pump and outside pump were working together, the motor output torque was superior to when they were working alone. When the fluctuation cycles of pump and motor were consistent, the motor output torque could be more stable by adjusting the lag angle reasonably. For verifying the correctness of the proposed theoretical analysis, the experimental platform of multi-pump and single-motor driving system was built, and the relevant data were collected to depict the diagram of uniformity coefficient of motor output torque in different working ways. The experimental result was consistent with the theoretical analysis, which showed the correctness of theoretical analysis.

Abstract:Aimed at the retrieval performance deficiency of the classic shape distribution algorithm in the field of professional CAD models, and to achieve the reuse of agricultural machinery CAD models better, a 3-D CAD model retrieval algorithm based on distance and area distributions was proposed to achieve the model similarity assessment. Firstly, hundreds of points were selected randomly on the grid of the triangular mesh surface, during which we adopted the quasirandom number generator and Halton-Sequence to generate random points to ensure the uniformity of corresponding points; then corresponding distance between two random points as well as area ratios between each surface were calculated, and the frequency of specific points was computed in the distance-area planar grid, forming a distance-area distribution matrix of a model; finally, we adopted the Manhattan to make an assessment about different matrixes to achieve the comparison of different CAD models. Area distribution is one of the essential characteristics of models. The innovation of this paper is that we put this factor and area feature into consideration. And the descriptor was distance feature with a fusion of area to implement the accurate depiction. Accuracy was higher compared with that of other methods with respect to same retrieval parts. Halton-Sequence was adopted to generate uniform random numbers and the sampling points can be reduced significantly due to this. Thus, efficiency was acceptable. Above all, test results show that the algorithm is better in the field of agricultural CAD models compared with other shape distribution algorithms for the similarity assessment.