灌浆对地下连续墙及邻近土体变形的影响

在地下连续墙深基坑开挖工程中,开挖前常用灌浆的方法来加固将被挖去的软土,从而减少地下连续墙的变形,增加开挖稳定性,保证工程安全,但是,在灌浆过程中,灌浆的作用机制以及对地下连续墙及邻近土体变形的影响原理还没有得到很好的研究,以新加坡艺术中心地下连续墙深基坑开挖工程为背景。实测了灌浆施工过程中,地下连续墙的变形、超孔隙水压力以及地下水位的变化;再结合有限元的理论分析方法,研究了灌浆施工对地下连续墙及     

大型企业库存管理中的数学模型——转库流向优化及时间推荐

在供应—生产—销售的供销环节中 ,大型企业的出厂决策问题是非常重要和难解决的。本文以某钢铁厂出厂决策支持系统为背景 ,对其中业务管理中的库存管理建立起数学模型体系。分析了模型的特点 ,由于 0— 1归划为 NP—难问题 ( NP—完全问题 )及一些问题属于大规模资源优化问题 ,当问题规模增大时求解变得极其困难。针对这些问题的特点介绍了求解模型的算法 :现有程序包、启发式算法和线性规划与启发混合的算法。这些算法在应用中取得了较好的效果。     

A sperm GPI-anchored protein elicits sperm-cumulus cross-talk leading to the acrosome reaction

The acrosome reaction has long been thought to be induced by the zona pellucida. Here we report the identification and function of a novel human sperm glycosylphosphatidylinositol (GPI)-anchored membrane protein, NYD-SP8. The release of the protein during sperm-egg interaction and its binding to the cumulus, the first layer of egg investment, elicits cross-talk between the gametes and produces calcium dependant release of progesterone, which lead to the acrosome reaction. An in vivo mouse model of NYD-SP8 immunization is also established showing a reduced fertility rate. Thus, contrary to accepted dogma, our study demonstrates for the first time that, prior to reaching the zona pellucida, sperm may release a surface protein that acts on the cumulus cells leading to the acrosome reaction, which may be important for determining the outcome of fertilization. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 11 August 2008; received after revision 18 December 2008; accepted 22 December 2008     

Modeling an Elastic-Demand Bimodal Transport Network with Park-and-Ride Trips

This paper presents a network equilibrium formulation for modeling commuters＇ travel choices in a bimodal transport system with park-and-ride （P＆R） trips while the total demand is elastic to the congestion level of the network. A super-network approach is adopted in the proposed model. It is assumed that commuters＇ trips are categorized into two types, auto mode only and a combined mode with both auto and transit modes. The former is referred to as the pure mode trip and the latter as the P＆R mode trip. The proposed model simultaneously considers the commuter＇s choice of the pure mode versus the P＆R mode, the choice of parking location for the pure mode, the choice of transfer point for the P＆R mode, as well as the route choice for each mode. The demand elasticity of transport system, the capacity constraints of transport facilities, and the congestion interaction throughout the super-network are also explicitly incorporated into the proposed model. The results of the numerical experiment show the following key findings： （i） traditional parking/P＆R models may overestimate or underestimate travel demand distribution over network; （ii） parking/P＆R, transit scheduling, and carpooling schemes bring significant impacts on commuters＇ travel behavior and network performance; and （iii） different transport policies may be to some extent mutually substituted .     

川东鄂西山地紫色土发生探讨

本文研究表明,在试验区内,地质构造决定着紫色岩层的展布和紫色土的分布;老年、壮年、青年等不同地貌发育阶段则深刻影响和制约紫色土发生演化的方向.在现代成土条件下,各地类型紫色土的发育和岩石,既存在矿质元素的相对迁移和富集.也存在元素间的彼此制约关系.实质为碱金属、碱土金属在土壤剖层次间的淋溶作用.土壤淋溶系数5.90-14.960;岩石淋溶系数2.269-4.466.     

基于DEA法的虚拟企业合作伙伴效益评价应用研究

虚拟企业合作伙伴选择是虚拟企业组建过程中的重要问题，也是一个复杂的问题。从虚拟企业合作伙伴效益评价的角度出发，在AHP(层次分析)法的基础上，给出了DEA(数据包络分析)法的C^2R模型，并结合具体企业进行了实例验证，从而证明了DEA法对于虚拟企业合作伙伴选择的科学性和有效性。     

贵州省两种新毒菌食物中毒的调查研究

本文首次报道了贵州省龙里县由亮耳菌和月夜菌引起的食物中毒,对国内尚未报道的亮耳菌中毒的临床表现特点、治疗及预防措施进行分析讨论,并对二种毒菌的生态环境、形态特征进行描述。