三阶时滞泛函微分方程解的渐近性

本文讨论一类三阶时滞泛函微分方程解的渐近性质,给出了若干解的有界性及解趋于零的判定准则.     

混合变元中立型微分方程的解的振动准则：献给李森林教授八十寿辰

本文得到了两类混合变元中立型微分方程的解的某些新的振动准则,大大改进了〔[5,7-9〕的结果.并推出了变系数的混合中立型方程.     

超临界增长椭圆方程组广义解的正则性

In this paper, the author proved the partial regularity of the generalized solutions of the super critical growth elliptic system. Furthermore, the everywhere regularity of generalized solutions of three special systems are obtained.     

牵引犁受力分析的解析方法

分析了牵引犁受力图解法求解所存在的问题，用解析方法建立了牵引犁受力的矩阵方程组并利用计算机进行了求解，预测了各结构参数变化对机组受力工况的影响，从而为牵引犁机组的合理配置和各部件结构的强度计算和优化设计提供了理论依据。     

非线性方程组拟牛顿法中线性搜索的一种改进

改进了Ｇｒｉｅｗａｎｋ（１９８６）提出了关于求解非线性方程组的一种线性搜索方式。在理论上保证了线性搜索的实现,使得算法是适定的,而且,在改进的线性搜索条件下,Ｂｒｏｙｄｅｎ算法仍具有全局收敛性和局部超线性收敛性。     

Modelling Plant Disease Epidemics

An epidemic is the progress of disease in time and space. Each epidemic has a structure whose temporal dynamics and spatial patterns are jointly determined by the pathosystem characteristics and environmental conditions. One of the important objectives in epidemiology is to understand such spatio-temporal dynamics via mathematical and statistical modelling. In this paper, we outline common methodologies that are used to quantify and model spatio-temporal dynamics of plant diseases, with emphasis on developing temporal forecast models and on quantifying spatial patterns. Several examples of epidemiological models in cereal crops are described, including one for Fusarium head blight.     

Meta‐analysis of the energy and protein requirements of hair sheep raised in the tropical region of Brazil

The objective of this study was to estimate, through mathematical models, energy and protein requirements for maintenance and gain of hair sheep raised in the tropical region of Brazil. To determine the equation parameters, a meta‐analysis of seven independent experiments of nutrient requirements was performed, comprising a total of 243 experimental units (animals), which were conducted under tropical conditions, using hair sheep in growing and finishing phases and endowed of the following quantitative data for each animal: body weight (BW ), empty body weight (EBW ), average daily gain (ADG ), empty body gain (EBG ), heat production (HP ), metabolizable energy intake (MEI ), retained energy (RE ), metabolizable protein intake (MPI ) and body protein content. The regression equations generated were as follows: for Net Energy for maintenance, (NE _m): ; for Net Energy for gain, (NE _g): ; for Metabolizable Protein for maintenance,(MP _m): MPI _(g/day) = 24.8470 (±7.3646) + 560.28 (±99.6582) × EBG _(kg/day); for Net Protein for gain, (NP _g): . The NE _m requirement was 0.246 MJ EBW^?0.75 day^?1. The metabolizable energy for maintenance requirement was 0.391 MJ EBW^?0.75 day^?1. Considering an ADG of 100 g, the NE _g requirement ranged from 0.496 to 1.701 MJ/day for animals with BW ranging from 10 to 40 kg respectively. The efficiencies of use of the metabolizable energy for maintenance and gain were 0.63 and 0.36 respectively. The MP _m requirement was 3.097 g EBW^?0.75 day^?1. Considering an ADG of 100 g, the NP _g requirement ranged from 12.4 to 10.5 g/day for animals with BW ranging from 10 to 40 kg respectively. The total metabolizable energy and protein requirements were lower than those reported by the NRC and AFRC systems. Thus, our results support the hypothesis that nutrient requirements of hair sheep raised in tropical regions differ from wool sheep raised in temperate regions. Therefore, the use of the equations designed in this study is recommended.     

一类半线性椭圆问题的瀑布型多重网格法

采用瀑布型多重网格法求解一类半线性椭圆问题.在适当条件下，证明了该算法具有能量范数意义下最优收敛阶和拟最优计算复杂度.     

冬枣果园土壤非交换态钾的释放动力学

为了研究长期施肥条件下冬枣果园土壤非交换态钾的释放特征,以Ca Cl2和柠檬酸溶液为浸提剂,采用连续提取的方法对枣园土壤的非交换态钾释放动力学进行研究。结果表明,枣园土壤非交换态钾在释放过程中表现出快速释放和缓慢释放2个连续的阶段。快速释放阶段(188 h)的累积释放量占到总释放量的53.6%~59.2%,而在缓慢释放阶段(188~1244 h)的释放量不及总量的一半。在相同时间内,使用柠檬酸溶液浸提时,非交换态钾的释放量明显高于使用Ca Cl2溶液时的释放量。相比之下,冬枣果园土壤非交换态钾的释放量明显高于对照土壤。在5种动力学方程中,幂函数方程是描述冬枣果园土壤非交换态钾释放的最优模型。