喷雾参数与飘移相关性分析

飘移是评价液体农药喷洒质量的重要指标。在影响喷雾飘移的因素中，喷头类型、喷头的大小(流量)和风速都有重要影响。分析它们对飘移的影响对于合理选择喷头和喷雾条件有重要意义。该文在试验的基础上，应用数学建模方法分析不同喷雾参数与飘移量之间的相关关系，并通过回归分析，确定它们对飘移量的作用程度，从而分离主要参数，为参数优化提供依据。研究结果说明，喷头类型、喷头大小和风速都对飘移有显著的影响，但作用强度不同，由强到弱依次为风速、喷头类型和大小。     

基于BP神经网络的土壤水力学参数预测

为了获取区域土壤水分和溶质运移模拟所需的土壤水力学参数,利用黄淮海平原曲周县的试验资料建立基于BP神经网络的土壤转换函数模型。本文采用土壤粒径分布、容重、有机质含量等土壤基本理化性质,来预测土壤饱和导水率Ks、饱和含水量sθ、残余含水量θr、以及van Genuchten公式参数α、n的对数形式ln(α)和ln(n),并与多元线性逐步回归方法进行比较。t检验结果表明,BP神经网络训练和预测得到的模拟值与实测值之间吻合很好,该方法具有较高的预测精度。通过对平均相对误差的比较,得出在粒径分布的基础上增加容重、有机质含量等输入项目,可以提高部分土壤水力学参数的预测精度,而有些参数的预测精度反而降低。以误差平方和为标准的比较结果表明,BP神经网络模型的预测效果总的来看要优于多元线性回归法。     

运输时间和温度对生猪应激和猪肉品质的影响

为了研究运输时间和温度对生猪应激及猪肉品质的影响,该文以三元杂交猪杜长大为研究对象,测定了运输前、运输3、6、9h以及运输温度-10~0℃、0~10℃、10~20℃、20~30℃等条件下生猪的血液生化指标、宰后猪肉p H值、肉色等指标。结果表明:运输6 h后三元猪出现应激反应,9 h以后应激反应显著增强(P0.05),运输6 h以上三元猪与运输3 h相比,宰后45 min p H值显著降低(P0.05),肉色分级显著升高(P0.05),肉品质降低;运输温度低于10℃时三元猪出现应激反应,-10~0℃时应激反应显著增强(P0.05),-10~0℃和20~30℃条件下宰后24 h p H值显著高于0~10℃和10~20℃(P0.05),肉品质降低。因此,为防止生猪运输应激及改善猪肉品质,生猪运输时间应小于6 h,运输温度为10~20℃。该研究结果对屠宰行业减少生猪应激提高猪肉品质提供参考。     

Optimization of Structure Parameters for Self Recirculation Burner

In the paper,the relationship between the structure parameters and P V characteristics and recirculation ratio of the burner are studied by the simulated experiment of a self recirculation burner.The optimum structure parameters of the burner are analysed and tested in the cases that the produced recirculation amaunt of optimal controlled NO x consumpting the lowest energy can be ensured.     

Optimizing Design of Planar Transformers Based on Integrated Software Platform

A method of optimizing planar transformers' design based on integrated software platform iSIGHT is presented.Through integrating the circuit simulation tool Saber and Maxwell 3D to the optimization tool iSIGHT,the parasitic effects on planar transformers are studied carefully.Changing the thickness of the insulator layer between the primary and the secondary can obtain different values of parasitic parameters and a new method to avoid parasitic oscillations with dangerous high voltage spikes to improve the SMPS performance is established.Hence an optimal design of planar transformer is obtained.The final optimal simulation analysis results verify the correctness of above theoretical study.     

INTRODUCTION TO A NEW AUTOPROGRAMMING SYSTEM FOR NC LATHE

This paper deals with the BCH autoprogramming system based on the principle of "representing shap with numbers", With this system, the organization of turning process can be accomplished by inputting only some codes and a few characteristic parameters, and the NC block instructions to control the NC lathe via control unit can be output in turn so that it is possible to write a part program at the shop floor which is benifitian for developing a new programming method to be used in a multistage computer manage system with communicating interface.     

胡麻主要经济性状遗传参数的研究

本文估算了胡麻主要经济性状的广义遗传力、遗传相关系数、遗传进度和选择指数等遗传参数.结果表明;千粒重、株高、工艺长度的遗传力、遗传进度较高,遗传变异系数较大,在早代进行一次选择即可;每果着粒、开花期的遗传力和遗传进度也较高,而变异系数较小.对其也应加强早代选择,并加大选择群体;单株粒数、主茎分枝的遗传力和遗传进度中等,应进行几代连续选择;单株粒重、单株结果的遗传参数值均较小,直接选择效果差,可通过显著相关的性状进行间接选择.特别是对于单株粒重,还可以用相对效率高的选择指数进行间接选择.     

Experimental Study about Activated Water Generated by Electro-hy draulic Impulse Improving the Mechanical Performance of Concrete

A new good idea named Electro-hydraulic Impulse is described in the paper. Electro-hydraulic impulse is a process which integrates strong electrical field, strong magnetic field, ultrasonic wave, radiation of light and cavitation. With it, a kind of water named strongly polar activated water is generated. Using strongly polar activated water to make concrete blocks, the mechanical performance of concrete can be improved greatly. With the proper parameters, the compression strength of concrete can be increased by 48% percent. This has been proved by some experiments.     

小五台亚高山草甸植物种分布的生境条件解释

通过野外植被调查获取小五台亚高山草甸的第一手植被数据,结合室内外测定和模拟的研究区景观尺度的生境特征指标,分析了研究区亚高山草甸地段植物物种与环境因子之间的定量关系。典范对应分析(canonical correspondence analysis,CCA)排序的结果表明,1)在小五台的亚高山草甸分布地段,热量、养分和水分条件构成了其生境特征差异的基本格局;2)依据研究区的物种在热量、养分和水分梯度上的分布位置,可以划分为暖干、冷干、暖湿、冷湿、凉干、普适和耐干扰型几类物种;3)对于生境温度、养分及水分有特殊偏好的物种可以较好地指示研究区的生境特征。