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。     

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.     

菜籽与菜籽仁散粒体的压榨塑性模型

进行了菜籽与菜籽仁散粒体侧限压榨下的应力应变关系、侧向压力试验.根据侧限压榨符合幂次硬化材料模型的试验结果,采用Doraivelu屈服准则,建立了基于增量理论的菜籽与菜籽仁散粒体侧限压榨塑性本构方程.结果表明,Doraivelu屈服准则可作为菜籽与菜籽仁压榨塑性模型的理论基础,压榨塑性模型能较好地描述菜籽与菜籽仁散粒体的塑性变形.     

Navier—Stokes方程的一种泛复数解

通过引入泛复变量求解Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，得到不可压缩流体Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的一种泛复数解，即速度场和压强场的泛复数表示。     

一类Lienard系统的中心—焦点问题

为了定性地研究微分方程系统，通常要讨论中心－焦点问题。本文讨论了一类Ｌｉｅｎａｒｄ系统，通过证明定理，指出连续奇，偶次这类系统在原点具有不同的拓扑结构（即相连奇，偶次系统不能同时为中心），以便于进一步求得该系统的焦点量上界问题。     

利用误差变量联立方程组建立南方杉木一元立木材积模型和胸径地径回归模型

利用我国南方的杉木实测数据,采用误差变量联立方程组方法,同时建立了胸径一元材积模型、地径一元材积模型和胸径—地径回归模型。结果表明:地径与胸径之间相关紧密,其回归模型的确定系数可以达到0.96以上;地径一元材积模型的预估精度要明显低于胸径一元材积模型。     

Assessment of biomass and net primary productivity of a dry tropical forest using geospatial technology

This study quantifies biomass, aboveground and belowground net productivity, along with additional environmental factors over a 2-3 year period in Barnawapara Sanctuary of Chhattisgarh, India through satellite remotesensing and GIS techniques. Ten sampling quadrates20×20, 5×5 and 1×1 m were randomly laid for overstorey (OS), understorey (US) and ground vegetation(GS), respectively. Girth of trees was measured at breast height and collar diameters of shrubs and herbs at 0.1 m height. Biomass was estimated using allometric regression equations and herb biomass by harvesting. Net primary productivity (NPP) was determined by Ssumming biomass increment and litter crop values. Aspect and slope influenced the vegetation types, biomass and NPP in different forests. Standing biomass and NPP varied from 18.6 to101.5 Mg ha^-1 and 5.3 to 12.7 Mg ha^-1 a^-1, respectively,in different forest types. The highest biomass was found in dense mixed forest, while net production recoded in Teak forests. Both were lowest in degraded mixed forests of different forest types. OS, US and GS contributed 90.4, 8.7and 0.7%, respectively, for the total mean standing biomass in different forests. This study developed spectral models for the estimation of biomass and NPP using Normalized Difference Vegetation Index and other vegetation indices.The study demonstrated the potential of geospatial tools for estimation of biomass and net productivity of dry tropical forest ecosystem.     

An Analysis of Thick Plates underIn-plane and Transversal Loadings by the BEM

In accordance with the behaviours of thick plates under the in-plane and transversal loadings,and introducing the concept of equivalent load, the coupled equations for the problem have been deduced with the theory of BEM in this paper.Thus a new method is presented for solving the problems of interaction of superstructure and foundation and subsoil,as well as for the problems of the thick plates under the complicated loadings.     

一类差分方程的渐近稳定性

研究了一类差分方程的渐近稳定性,获得了该方程平衡解全局渐近稳定的充分必要条件。     

Using an ADCP to determine canal seepage loss in an irrigation district

Seepage from earthen irrigation canals represents substantial water loss in irrigation districts. Historically, the determination of canal seepage was accomplished using the inflow-outflow method with propeller and electromagnetic type flow meters. This method was difficult, time consuming, and limited by measurement device accuracy. In recent years, advances in technology have lead to the widespread use of Acoustic Doppler Current Profilers (ADCP) for discharge measurements in streams and rivers. Even though ADCP use has become widespread for stream discharges, studies to determine canal seepage using this new technology are limited. Using an ADCP, extensive field measurements were conducted in the Middle Rio Grande Conservancy District. This paper describes the ADCP measurement protocol used to measure irrigation canal seepage and presents predictive equations for determining canal seepage based on flow rate and canal geometry.