单株幼龄苹果树修剪仿真研究

修剪是果树生产中重要的技术手段,要想研究更加合理的修剪技术体系,就必须保证能够对修剪反应有准确、直观和及时的判断,而仿真模拟技术提供了这种可能。以幼龄苹果树为研究对象,采用不同修剪处理对比的方法,在田间试验的基础上,总结修剪反应规律,构建苹果树结构和修剪模型。在此基础上基于Qt框架和OpenGL图形库,开发了单株苹果树修剪仿真软件平台。结合优化算法,通过仿真平台模拟了给定生产目标的修剪方案优化,优化结果对虚拟学习和实际生产提供了可视化指导。     

Crop response of drought-tolerant and conventional maize hybrids in a semiarid environment

In the High Plains, corn (Zea mays L.) is an important commodity for livestock feed. However, limited water resources and drought conditions continue to hinder corn production. Drought-tolerant (DT) corn hybrids could help maintain high yields under water-limited conditions, though consistent response of such hybrids is unverified. In this two-year study, the effects of three irrigation treatments were investigated for a DT and conventional maize hybrid, Pioneer AQUAMax P0876HR and Pioneer 33Y75, respectively. In 2013, the drier of the 2 years, irrigation amounts and crop water use (ET_c) were greater for the conventional hybrid, but grain water use efficiency (WUE) and harvest index were significantly greater for the DT hybrid. In 2014, grain yields and WUE were not significantly different between hybrids. However, irrigation amounts, ET_c and biomass yields were greater for the conventional hybrid. Results from both years indicate that the DT hybrid required less water to maximize grain yield as compared to the conventional hybrid. Producing relatively high yields with reduced amounts of water may provide a means for producers to continue corn production in a semiarid environment with declining water supplies.     

基于多信息融合的疫苗制备中鸡蛋胚体分拣系统

采用多信息融合方法研究疫苗制备中鸡蛋胚体状态的识别与分拣技术。在研究不同状态鸡蛋胚体图像特征、温度衰减和透光度变化情况的基础上,得出活胚图像中血管多、粗且呈放射状,弱胚图像中血管少、细且断裂,死胚图像内部均匀无血管,污染胚图像内部有明显黑块特征;鸡蛋胚体从37.8℃的孵化箱中取出置于25℃室温环境,活胚、弱胚、污染胚、死胚的温度衰减速度依次增大;活胚的透光度随孵化时间增加而逐渐降低,其他胚体透光度变化相对较小。将图像、温度、透光度信息特征融合,建立BP神经网络信息融合模型对鸡蛋胚体状态进行识别。最后,从37.8℃孵化箱中抽取80枚孵化6 d的鸡蛋胚体放置于室温10 min后,采集图像、温度和透光度信息,进行试验验证。结果表明多信息融合系统的识别准确率为96.25%,比单用图像、温度和透光度传感器进行识别的准确率分别提高了6.25%、13.75%和8.75%。     

Modeling soil water dynamics in a drip-irrigated intercropping field under plastic mulch

Intercropping, drip irrigation, and the use of plastic mulch are important management practices, which can, when utilized simultaneously, increase crop production and save irrigation water. Investigating soil water dynamics in the root zone of the intercropping field under such conditions is essential in order to understand the combined effects of these practices and to promote their wider use. However, not much work has been done to investigate soil water dynamics in the root zone of drip-irrigated, strip intercropping fields under plastic mulch. Three field experiments with different irrigation treatments (high T1, moderate T2, and low T3) were conducted to evaluate soil water contents (SWC) at different locations, for different irrigation treatments, and with respect to dripper lines and plants (corn and tomatoes). Experimental data were then used to calibrate the HYDRUS (2D/3D) model. Comparison between experimental data and model simulations showed that HYDRUS (2D/3D) described different irrigation events and SWC in the root zone well, with average relative errors of 10.8, 9.5, and 11.6 % for irrigation treatments T1, T2, and T3, respectively, and with corresponding root mean square errors of 0.043, 0.035, and 0.040 cm³ cm^?3, respectively. The results showed that the SWC in the shallow root zone (0–40 cm) was lower under non-mulched locations than under mulched locations, irrespective of the irrigation treatment, while no significant differences in the SWC were observed in the deeper root zone (40–100 cm). The SWC in the shallow root zone was significantly higher for the high irrigation treatment (T1) than for the low irrigation treatment, while, again, no differences were observed in the deeper root zone. Simulations of two-dimensional SWC distributions revealed that the low irrigation treatment (T3) produced serious severe water stress (with SWCs near the wilting point) in the 30–40 cm part of the root zone, and that using separate drip emitter lines for each crop is well suited for producing the optimal soil water distribution pattern in the root zone of the intercropping field. The results of this study can be very useful in designing an optimal irrigation plan for intercropped fields.     

玉米收获机拉茎辊的改进设计

针对摘穗板-拉茎辊组合式摘穗装置在玉米收获过程中存在的问题,对拉茎辊进行改进设计。改进后的拉茎辊叶片轴采用无缝钢管经模具拉伸成型,整个叶片轴是一体的,叶片棱面为圆弧结构,并且将叶片轴后端与销轴连接的卡槽尺寸加大,加装金属耐磨套。该改进方案解决了传统拉茎辊易开焊、振动大、寿命短等问题。利用Solid Works软件对改进后拉茎辊进行有限元分析得知:应力和最大应变主要分布在拉茎辊后端的U型槽内,最大位移分布在叶片棱上,都在材料的变化范围内,改进方案合理。     

计算机图解适线法

该文编制的计算机图解适线法程序,对于总体为皮尔逊Ⅲ型分布的样本系列,能够利用计算机屏幕(或绘图仪)目估适线。主要计算结果为适线法确定的参数X、CV和CS,以及任何指定频率的设计值XP。     

黄河流域典型灌区灌溉节水管理模型研究

以黄河流域上下游2个典型灌区为背景，针对灌区有其农业水管理现状，开发了灌溉节水策略分析决策支持系统（DSS）原型。DSS是一个规划工具，通过对不同策略下田间配水及供水系统的模拟分析及综合决策，寻求最优的策略集合，以达到节约灌溉用水量、提高农业用水效率及维持农业可持续发展的目的。该DSS系统主要用于黄河流域灌区提高农业水管理水平的策略分析，也可用于评估灌区续建配套及土地最佳利用方案等方面。     

格尔木水电一分厂微机监测与故障诊断

简介了全分布式控制网络构成的水电厂微机监测系统的结构、功能和故障诊断系统。它不仅能实时监测机组运行参数，且可对事故做出快速反应，大大提高了水电厂安全运行水平。由于网络采用总线拓扑结构和真正的全分布方式，因而在老电厂的技术改造中，不仅运行可靠、抗干扰能力强，且布置安装简便，投资省。     

Sensitivity analysis of optimal operation of irrigation supply systems with water quality considerations

A model for optimal operation of water supply/irrigation systems of various water quality sources, with treatment plants, multiple water quality conservative factors, and dilution junctions is presented. The objective function includes water cost at the sources, water conveyance costs which account for the hydraulics of the network indirectly, water treatment cost, and yield reduction costs of irrigated crops due to irrigation with poor quality water. The model can be used for systems with supply by canals as well as pipes, which serve both drinking water demands of urban/rural consumers and field irrigation requirements. The general nonlinear optimization problem has been simplified by decomposing it to a problem with linear constraints and nonlinear objective function. This problem is solved using the projected gradient method. The method is demonstrated for a regional water supply system in southern Israel that contains 39 pipes, 37 nodes, 11 sources, 10 agricultural consumers, and 4 domestic consumers. The optimal operation solution is described by discharge and salinity values for all pipes of the network. Sensitivity of the optimal solution to changes in the parameters is examined. The solution was found to be sensitive to the upper limit on drinking water quality, with total cost being reduced by 5% as the upper limit increases from 260 to 600 mg Cl l^–1. The effect of income from unit crop yield is more pronounced. An increase of income by a factor of 20 results in an increase of the total cost by a factor of 3, thus encouraging more use of fresh water as long as the marginal cost of water supply is smaller than the marginal decrease in yield loss. The effect of conveyance cost becomes more pronounced as its cost increases. An increase by a factor of 100 results in an increase of the total cost by about 14%. The network studied has a long pipe that connects two distinct parts of the network and permits the supply of fresh water from one part to the other. Increasing the maximum permitted discharge in this pipe from 0 to 200 m³ h^–1 reduces the total cost by 11%. Increasing the maximum discharge at one of the sources from 90 to 300 m³ h^–1 reduces the total cost by about 8%.     

履带拖拉机支重轮的塑变磨损研究

采用有限元分析方法对履带拖拉机支重轮在工作过程中所受接触应力进行了计算，并进行了实验室磨损试验和试车磨损试验，深入研究了支重轮的磨损形变机制。结果表明：支重轮由于具有较低的轮面硬度和较大边缘接触应力，因此在较短的工作期间内发生严重的塑变磨损，进而产生变形、失效；感应加热表面淬火可以大幅度提高支重轮的轮面硬度，能够有效提高支重轮的耐磨性。