种内竞争对桔小实蝇种群动态的影响

研究种内竞争对桔小实蝇的个体大小、存活率、生物量及产卵量的影响,并进行了模拟分析。对影响种群动态的诸要素建立模糊集,用贴近度方法进行关键要素分析。在种内竞爭条件下,成虫产卵量是影响世代趋势指数的关键要素,蛹生物量是影响下代虫口密度的关键要素。     

Parametric design of an electrorheological shock absorber with the mixed-mode

1. Introduction As is known, the function of a suspension system is to support an entire vehicle at axles so as to improve ride comfort by vibration absorption. It also provides handling stability in steering and acceleration as well as braking. However, the solution of the design contradiction between ride comfort and handling stability can抰 be achieved by passive suspension system elements. Some active suspension systems have been developed in order to handle the compromise, but they requi…     

电激法转移质粒扩大苏云金杆菌杀虫谱

应用高压电激法,把载有表达不同杀虫谱晶体蛋白基因的两种质粒同时转入晶体缺陷型的BT菌株,或者把载有表达单一晶体蛋白基因的质粒转入不同亚种且产生晶体的天然BT菌株中,通过生物测定法,快速而简便地筛选出杀虫谱扩大及杀虫毒力提高的重组菌株。所筛选到的菌株产生的伴孢晶体,同时对鳞翅目及双翅目昆虫幼虫有毒杀作用,并且重组菌株所产生的伴孢晶体的形状有异于其出发菌株的伴孢晶体。     

Understanding kiosk navigation: Using log files to capture hypermedia searches

The purposes of these studies were to investigate: a) the role of different intentions for constraining kiosk searches; b) whether selected variables related to reading comprehension (e.g., prior content knowledge) were also related to document search; and c) the potential of log files (timed-stamped records of students' navigational choices in the kiosk) as a non-intrusive tool for seamlessly capturing navigational performance. In Study 1, 64 college students were recruited and randomly assigned to one of two conditions. Both groups used an identical computer kiosk. However, one condition used the kiosk to address a specific problem, while the other condition used the kiosk based on their own interests-no specific task was provided. A discriminant function analysis was able to improve prediction about the group membership by 79% (adjusted with Cohen's Kappa) over and above chance. In Study 2, 54 participants were randomly assigned a simple or complex task. Participants were pretested on prior topic knowledge and solutions were rated based on a composite of navigational scores. Although prior content knowledge and the interaction were not significant, the type of task assigned was related to the quality of solution. These results provide further reason to distinguish between document search and reading comprehension. Further, they suggest new tools for assessment (log files) that have implications for many computerized applications, including hypertext, hypermedia, and the World Wide Web.University of Connecticut at Storrs     

用遗传算法求解非线性方程组

利用遗传算法能通过求解正问题而达到求解反问题的特性,提出了一种全新的求解非线性方程的方法,该算法具有普适性、全局收敛性及编程简单、计算量小等优点,通过一些计算实验,进一步证明了该方法的有效性。     

国家信息资源价值最大化的边际条件与决策模型

国家信息资源（NIR）是推动国家竞争力提升的战略性资源。NIR的内容体系由物理层、元数据层、国家基础数据层、分类信息层和国家决策信息层五个层面构成。探讨实现NIR价值最大化目标的边际条件,描绘NIR的边际成本与边际收益曲线;并基于目标规划方法建立NIR投入优化决策模型。     

An overview on research developments of toroidal continuously variable transmissions

1. Introduction Over the past century, the advancements of research and development in fuel economy and emissions have been retarded, in spite of implementation by depleting a lot of money. Thus, the ideal interim solution is to further optimize the overall efficiency of internal combustion engine (ICE) vehicles. One potential solution to treat the fuel economy dilemma is the toroidal traction drive CVT, an old concept that has only recently become the hope to automotive makers. Toroidal C…     

Indirect Searches of Dark Matter in Space

Dark matter(DM) is a form of matter necessary to account for gravitational effects observed in very large scale structures such as anomalies in the rotation of galaxies and the gravitational lensing of light by galaxy clusters that cannot be accounted for by the quantity of observed matter (Bertone et al.2005).In the standard cosmology model.