谷物收获超声波流量计的前期研究

以多普勒法的谷物收获超声波流量计为研究对象,进行谷物收获系统和超声波流量计的前期研究.超声波流量计是利用流体对超声波的影响来测量流量的仪表,传统的测量原理一般为时间差法,测量精度低,只能对液体或者气体进行流速测量;而采用多普勒测量法则可以达到更高的测量精度,并且尝试对谷物(固体)的流速进行测量.     

调速器主配中位自动诊断及智能纠偏技术研究与应用

液压随动系统主配电气中位未整定准确和温漂作用是调速器系统出现主配频繁调节的主要原因之一。技术人员对调速器液压随动系统进行深入的理论研究,提出了静态平衡理论和主配中位纠偏原理,探索出了主配电气中位自适应方法,进而通过调速器电气控制系统自适应控制功能软件开发,实现了主配电气中位自动诊断及智能纠偏功能,并通过真机测试验证其功能效果,完美解决了液压随动系统主配电气中位未整定准确或由于温漂作用导致的调速器系统主配频繁调节问题,保证了机组和电网安全稳定运行。     

浙江省农业机械化水平的总体评价与地区比较

为科学评价农业机械化发展水平,在分析现有农业机械化水平评价方法的基础上,根据浙江省农业机械化发展现状及有关文献,建立和确定了浙江省农业机械化水平评价指标体系、评价标准以及各评价指标的权重;最后,利用2005年浙江省和其所属11个地(市)的有关统计数据计算出全省和各地区的农业机械化水平.评价结果表明,与实际情况基本一致,为加强农业机械化的宏观管理提供了科学依据.     

不同出口角离心油泵叶轮切割性能实验

对不同出口角的离心油泵叶轮直径进行了切割，当输送清水时，对离心油泵性能的变化情况和切割定律的影响进行了实验研究。结果表明，随着叶轮直径的减小，最优工况点向着流量减小的方向移动；泵在第一次切割后，即叶轮直径为205mm时，最优工况点的效率有所上升，出口角越大效率上升的幅度越大。关死工况下．扬程切割指数和轴功率切割指数分别近似等于常数。最优工况下，流量、扬程、轴功率和效率切割指数与现有理论值不同。     

起重机吊臂有限元模态分析

利用ANSYS软件对起重机吊臂进行了有限元模态分析,得出了各阶模态下吊臂的固有频率和振型,找到了吊臂振动中的危险区域,为产品设计和改进提供了理论依据。     

灌溉水利用系数综合测定法实例分析

灌溉水利用系数是衡量农业节水效果的关键指标。目前各地区统计出的灌溉水利用系数差异极大。很多数据明显的存在错误，难以作为比较与衡量的标准。影响灌溉水利用系数正常测定的主要原因是传统测定方法存在测定工作量巨大、测定条件难以保证等。通过开展对灌溉水利用系数资料的搜集、整理并对灌区进行实地调研，在了解目前灌区灌溉水利用系数测量中存在问题及原因的基础上，对灌区灌溉水利用系数测量计算方法进行了分析研究，提出了测定灌溉水利用系数的综合测定计算方法。该方法既克服了传统测量方法中工作量大，需要大量人力、物力才能完成的缺点，又弥补了只测量典型渠段而引起较大误差的不足，而且能反映出灌区渠系用水情况、灌溉工程质量及灌溉用水管理水平等。以漳河灌区为例进行了应用分析。     

354拖拉机与1.5m旋耕机配套性能分析

通过动力特性分析,解决了拖拉机动力输出轴转速高,输出扭矩较小,不能克服土壤对旋耕机的阻力矩,无法正常作业的问题.     

泵站优化运行算法

通过对动态规划法、线性规划法、非线性规划法及遗传算法等泵站优化运行算法的综述，对泵站运行优化方法的发展提出新的看法。     

高效数据库应用研究

效率是数据库应用开发过程中经常遇到的问题。为此，对数据库应用中影响效率的相关因素(如大事务、数据库连接等)进行分析，并针对实际电子商务数据库0RACE9I与JAVA应用中出现的问题，提出了解决方案。     

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%.