车用永磁式缓速器电磁场计算、设计研究

利用ANSYS软件对永磁式缓速器的电磁场进行计算。基于数值计算结果,重点分析了材料区和气隙的磁感应强度的分布特性,并对理论计算结果进行分析,以深入了解其电磁场特性及工作机理,同时还对车用永磁式缓速器电磁场进行了参数设计。     

田间土壤力学参数测定方法研究

总结了车辆地面力学研究常用的土壤力学参数检测方法,结合现代农业车辆智能化发展思想,提出了结合车辆动力学参数的在线检测进行土壤力学参数估计的方法。     

木捆排排型参数对其运行水阻力影响的试验研究

本文研究了木捆排在无限水域中的运行水阻力问题,提出了排型参数(L/B)和(B/T)对木捆排运行水阻影响程度的试验数据和图表,探讨了降低木捆排运行水阻力的途径及措施。     

土壤肥力和灌水量组合对不同类型小麦光合特性及产量的影响

旨在为小麦节水高产栽培提供理论依据。在池栽条件下,研究了不同土壤肥力和灌水量组合对中筋小麦‘济麦22’和强筋小麦‘济麦20’旗叶净光合速率(Pn)、叶绿素荧光参数及产量构成的影响。2种小麦开花后各生育时期旗叶的光合速率Pn 值、叶绿素荧光参数Fv/Fm 值（PSⅡ最大光化学量子产量）和ФPSⅡ 值（PSⅡ实际光化学量子产量）均随着土壤肥力和灌水量的增加而提高,但土壤肥力因素对上述光合特性指标的影响大于灌水方式因素。随着土壤肥力的提高,Pn 和ФPSⅡ 开始下降的时间逐渐向后延迟,提高土壤肥力有利于减轻环境胁迫对光合的抑制作用。对于2 种小麦的产量和产量构成的影响,土壤肥力和灌水方式之间具有补偿效应。在土壤肥力较高的条件下,2 种小麦限量灌溉和充分灌溉之间产量差异并不显著。培肥地力可以减缓小麦灌水不足导致的光合性能指标的下降,维持生育后期较高的光合产物积累水平。     

太行山前平原土壤水分特征曲线拟合参数的确定

本文分别用BrooksandCorey ,vanGenuchten和Broadbridge White模型拟合了太行山山前平原不同层次土壤水分特征曲线 (SWC) ,并用Mualem和Burdine模型计算了土壤非饱和导水率(K)和扩散率 (D)。最能较好计算实验地点D和K的方法是用vanGenuchten模型拟和SWC(约束条件m =1- 2 /n) ,用Burdine方法计算K和D。     

基于夭折试验样本寿命分布的参数估计

研究了在夭折试验样本下指数分布与威布尔分布的参数估计问题。     

Genetic and Environmental Correlations Among Female Fertility Traits and Milk Production in Different Parities of Swedish Red and White Dairy Cattle

The main objective of this study was to estimate genetic correlations between fertility and production traits in first, second and third lactations as well as between fertility traits measured in the same way at different ages. The fertility traits studied were: number of inseminations per service period, number of treatments for reproductive disturbances, interval between first and last inseminations, interval between calving and first insemination, and interval between calving and last insemination. Early milk production was measured as the average of the energy-corrected milk yield at the second and third monthly testdays in a lactation. The number of records was approximately 450 000, 350 000, 180 000 and 75 000 in the heifer period, first, second, and third lactations, respectively. A linear, trivariate model that included the effects of herd-year, year, month, age and sire of the cow was applied. To reduce the effect of ongoing selection, 305-days kg protein production in first lactation was included as a variate in all of the analyses. Correlations between the herd-year effects indicated that factors of herd-year level conducive to increased production had a tendency to increase the number of inseminations as well as the number of reproductive treatments, although there was an earlier start and termination of the insemination period. Genetic correlations between fertility traits and production were in the range of 0.2-0.4, all of them unfavourable and higher at later parities. The genetic correlations between fertility traits in the heifer period and the same traits in first lactation were 0.7. Genetic correlations between the first and second lactation varied between 0.7 and 0.9, and between the second and third lactation they were all 0.9 or higher. In conclusion, fertility and production traits need to be selected for simultaneously if fertility is going to be maintained along further genetic improvement on production, and such selection should include fertility results from lactating cows.     

种间关联参数在Microsoft Excel 2003中的实现——Spearman秩相关分析

种间关联分析是认识植物群落的重要基础。针对种间关联参数计算过程复杂、繁琐、易错等特点,以Spearman秩相关分析为例,提出利用Microsoft Excel 2003的基本功能进行数据处理,快速高效地计算出Spearman秩相关值参数,对其他常用的种间关联参数的计算具有推广性。     

板料参数对抗皱性的综合影响研究

应用多元统计分析方法进行板料参数对抗皱性的综合影响研究，得到的全回归方程能客观地反映各种参数对抗皱性的影响程度和影响方式。为分析板料在成型过程中产生的缺陷和生产具有高抗皱性的板材提供依据。     

遗传算法率定参照作物腾发量相关参数的研究

用气象资料计算参照作物腾发量(ET0)的方法需要各种气象(候)和物理参数,净辐射是其中的重要数据之一,而专业测量净辐射的设备在农业气象站里很少安装。为解决计算ET0时缺少太阳净辐射(Rn)测量值这一实际问题,该文采用浑善达克沙地东南缘南沙梁草甸草原区气象站观测的气象资料,用遗传算法模型对联合国粮农组织56号文本(FAO56)推荐值(as和bs)进行率定,计算了对应夏半年(4—9月)和冬半年(1—3月和10—12月)的太阳净辐射和参照作物腾发量,并将率定前后的模拟太阳辐射进行对比分析,用残差估计指数法对该方法模拟的参照作物腾发量模拟精度进行了分析。结果表明:在缺少太阳净辐射测量值的地区,采用FAO56参数(as和bs)推荐值与遗传算法模型率定参数(as和bs)相比,净辐射年内变化趋势一致,采用率定后参数计算的净辐射相对更不稳定,波动更大,但能有效提高参照作物腾发量计算精度。误差较大的模拟值均出现在降雨日前后,降雨虽然并未直接出现在Penman-Monteith公式中,但是降雨必然会对湿度和温度等气象条件造成一定影响,而as和bs是受湿度等因素影响而变化的,其深层次的原因有待进一步分析。