汽车稳态圆周行驶初始条件的判定

利用统计拟合方法建立了轮胎侧向附着特性力学模型,并进一步分析了汽车运动和受力的几何关系,求解出了汽车稳态圆周行驶的初始条件,为进行汽车操纵稳定性的仿真研究提供了前提条件。     

2JT-M-2014型茄果类蔬菜嫁接切削器的研制

针对茄果类蔬菜气动嫁接切削器价格较高、作业不方便等问题,研制出2JT-M-2014型手动切削器,有效解决了以上问题。为检测其性能,设计了以切削苗切削作业质量为目标函数,以刀片磨损度、切削苗茎径和切削速度为影响因素的三因素三水平试验。试验表明:刀片磨损度是主要的影响因素,植物茎秆直径和切削速度对切削效果影响不大;刀片磨损微小时,切削表面拉丝少而短,更有利于后期嫁接作业。另外,通过对切削器顶丝伸出高度和植物切削角度关系的测试,得出该切削器的切削角度可在35°~51°内调节。     

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。     

连杆式机动水稻插秧机万向联轴系统的运动分析

以 2 ZT-935 型水稻插秧机为例,对不等角速双万向联轴器的输入轴 1与输出轴 3的运动关系进行了深入研究,比较精确地推导出轴1、3与中间轴2的夹角θ_1、θ_3(见图1)随转弯角度β变化的关系式,绘制了轴3的角速度ω_3、角加速度α_3的变化规律曲线图。为分析插秧系统的运动学、动力学问题和插秧质量提供了依据。     

基于视觉测量的挖掘机工作装置姿态测量系统

提出了一种基于视觉测量的挖掘机工作装置姿态测量方法。使用工业相机获取工作装置侧视图像,采用鞍点检测方法快速捕捉工作臂上的人工靶标;将靶标间的固定几何尺寸关系作为约束条件筛选出靶标中的鞍点并计算相应工作臂的姿态角;通过预判靶标的运动范围以缩小图像检测区域,提高算法处理速度。试验表明,与挖掘机上原有的拉线传感器测量系统相比较,动臂和斗杆姿态角动态测量偏差分别小于1°和2°,处理每帧工作装置运动图像平均用时在100 ms以内,验证了该方法对挖掘机工作装置姿态测量的可行性。     

智能粮食水分测试仪的研制

给出以AT89C52单片机为核心的粮食水分测试仪的硬件结构组成,并详细介绍了信号处理和测量方法;通过对传感器的标定并进行相应的数据处理。通过实验发现,该仪器使用方便,测量精度高。     

Basic handling characteristics of wood fuels: Angle of repose,friction against surfaces and tendency to bridge for different assortments

Basic handling characteristics were measured for sawdust, fuel pellets, fuel chips, hog fuel and chunkwood. The aim was to find relations between the basic handling characteristics and easily measurable fuel properties to facilitate the design of feeding systems in heating plants. The angle of repose was 25–55° and increased with the increasing ratio of particle length to thickness and with the increasing content of hooked or long particles. The angle of static friction, 10–40°, was affected more by the kind of surface than the fuel and followed the ascending order: coated plywood, urethane rubber, particle board, stainless steel, concrete and rubber belt conveyor. The tendency to bridge varied considerably and increased with greater content of hooked or long particles, a deeper fuel bed depth over the opening and a higher moisture content. The results indicate that more attention should be paid to the particle shape.     

木材表面非极性化原理的研究 Ⅱ.木材与苯乙烯接枝共聚过程中化学官能团和表面极性的变化

通过对杉木、杨木木材及其主要成分在与苯乙烯接枝共聚反应过程中化学官能团及临界表面张力变化的研究,探讨了木材各化学组成在接枝共聚过程中的反应性能和对木材表面极性的影响。研究表明:木材可与苯乙烯发生接枝共聚反应,反应只在木素和苯乙烯之间进行。木材与苯乙烯接枝共聚可降低木材临界表面张力,即降低木材表面自由能,从而有效地改善木材的极性。     

Morphological Basis of Resistance in Cotton to the WhiteflyBemisia Tabaci

The morphological basis of resistance to the whiteflyBemisia tabaci Genn. (Aleyrodidae: Hemiptera) was studied. The plant characters examined were leaf area, thickness of leaf lamina, hair density, hair length, angle of insertion of leaf hair, and density of gossypol glands. Hair density and leaf thickness were positively correlated with the population ofB. tabaci, and a positive correlation was obtained between the adult whitefly population and gossypol glands on stem internodes. Cotton genotype USA-22 (sparsely hairy) was found to be more tolerant toB. tabaci than was genotype USA-13 (velvety hairy). The use of thinner and glabrous leaved cotton varieties is suggested to minimize the whitefly menace in cotton.