不同N水平紫色土上不同水稻品种吸收N、K的动力学

A pot experiment was conducted to study the effect of nitrogen fertilizer on nitrogen and potassium uptake by four rice cultivars. Results showed that the quadratic parabola relationship between biomass of rice and nitrogen levels was observed, with the maximum biomass at the nitrogen level of 150 mg kg^-1. The rates of nitrogen and potassium uptake by the four rice cultivars depended on growth stage and rice cultivar with the maximum rate of N in Shanyou-63 and maximum rate of K in Kaiyou-5 (hybrid rice), respectively. The kinetics of nitrogen and potasssium uptake by rice plant could be quantitatively described by the following equations: y = a + blogt, y = ab + t^1/2 and y = ae^-bt. The b value in the equations was correlated significantly to the rates of nitrogen and potassium uptake (N_R and K_R, r = 0.901^**~0.990^**), suggesting that the b value could be used to distinguish the index of nitrogen and potassium uptake capacity of rice. The maximum values of nitrogen uptake by plant (b value) and apparent recovery of fertilizer nitrogen were observed in Shanyou-63, and the minimum value in Eryou-6078. However, the capacity of potassium uptake (b value) by Kaiyou-5 ranked first and that by Shanyou-63 second. There was a significant linear relationship between nitrogen level and nitrogen uptake by rice, but a quadratic parabola relationship was found between nitrogen level and patassium uptake by rice. The application of nitrogen fertilizer decreased the ratios of potassium to nitrogen uptake by rice plant. The greatest reduction in the ratio was observed at high nitrogen level, and the least reduction was found in Kaiyou-5 and Shanyou-63 due to their greater ability to absorb potassium.     

非算子型泛函微分方程概周期解的稳定性

利用指数型二分性理论及相关分析技巧，研究了一类具有有限时滞的非算子型的中立型泛函微分方程的概周期解问题，得到了方程存在唯一稳定的概周期解的新结果．     

Economics of p fertilization of two soybean varieties at Jabalpur,M.P., India

Abstract

An economic interpretation was applied to a soybean yield prediction equation derived from data obtained in an experiment at Jabalpur, M.F. It was shown that no level of applied P could substitute for variety selection in terms of either soybean yield or economic returns per ha. Illustrative examples of the minimum price that must be obtained for soybeans before it is profitable to use P fertilizer for given price situations were shown.     

对多分子马达输运中货物速度的讨论

从朗之万方程出发；对多分子马达输运过程中的货物速度进行了修正，得到了货物速度和马达个数的关系，修正以后的结果与试验值符合的相当好．为多分子马达输运机制的研究提供了新的思路和方法。     

出材率表简易编制方法研究——以浙江省开化林场人工林为例

利用浙江省开化林场杉木(Cunninghamia lanceolata)人工林的标准地和树干解析数据,建立带/去皮胸径预估模型:D去=-0.152+0.939D,一致性削度方程:d2/D2=1.113-1.435×(h/H)+0.329×(h/H2),编制了出材率表,精度检验结果满足要求。为森林经营单位提供了一种相对简单、实用的出材率表及其编制技术。     

密云水库小流域非点源污染负荷估算研究

采用Johnes输出系数法以及SCS径流曲线和通用土壤流失方程估算法,对密云土门西沟小流域非点源污染负荷进行估算。结果表明,土门西沟小流域内附着态污染负荷的输出量是溶解态污染物输出量的3倍多,而附着态污染物输出量的大小主要由土壤侵蚀量决定,因此,控制流域内非点源污染的关键是加强该区的水土保持防治工作。Johnes输出系数法可用于观测资料比较缺乏的流域,而SCS径流曲线和通用土壤流失方程估算法除了可以估算总氮、总磷的含量外,还能分别估算出溶解态氮、磷和附着态氮、磷的量,使得防治非点源污染的措施可以更加有针对性。     

日本胴体产肉率方程对我国牛胴体评价的适用性研究

用ＳＡＳ软件对１５２头商品牛的屠宰数据进行统计分析。通过产肉率方程的估测值与实测值的相关及回归分析，初步认为，日本方程对我国晋南牛胴体产率具有一定的预测作用，预测准确率为６６．７８％，但高估了约１０个百分点。但对鲁西牛、杂交牛（西门达尔×南阳牛）、北牛等无预测作用。     

脉冲时滞差分方程解的振动性与非振动性

讨论了一类冲时滞差分方程并分方程解的振动与非振动的充分条件，有着振动性的结论同样适用于不于带脉冲扰动条件的差分方程。     

基于超越方程的喷泉自适应控制模型研究

分析风对水滴的影响所产生的偏移，得到在风力作用下的水滴偏移方程，由此建立风速与水初速度的关系；通过对基本模型的优缺点分析，改进后得到更符合实际情况下的风速与水的初速度的关系，给出解决在风的作用下水滴偏移对游客产生的负面影响的优化控制模型。综合考虑实际情况，给出模型进一步改进的方向，从而进一步扩大模型的应用范围。     

结构可靠度的一种计算方法

提出一种推广一次二阶矩法的算法，解决了关于相关正态随机向量的非线性极限状态方程下结构可靠度计算问题，在理论上论证了方法的可行性，实例计算表明了方法的有效性。