Motivation profiles of urban preservice teachers: Relations to socialization,initial career perceptions,and demographics

Given the perennial challenge of attracting and retaining high-quality teachers, especially in large cities, there is a need to understand why preservice teachers in urban districts choose a teaching career, their perceptions of the profession, and how these relate to their initial career commitments and aspirations. Using latent profile analysis, we examined patterns of motivational perceptions with variables from the Factors Influencing Teacher Choice model alongside perceived task effort cost, opportunity cost, and emotional cost of teaching within a diverse sample of 630 preservice teachers. We identified four distinct profiles that differentially related to theorized antecedents (prior teaching and learning experiences, social encouragement, fallback career) and outcomes (satisfaction, planned persistence, planned professional development, leadership aspirations). Race, gender and certification-level were distributed in unique patterns across profiles. Results provide a holistic perspective of preservice teacher motivations and indicate that perceived costs in relation to FIT Choice variables were a defining characteristic of motivational patterns.     

谈谈新闻报道的标题

本文分析了新闻报道标题在修辞和语言方面的特点，提出标题赏析有助于培养学生的语言能力。     

Optimal design of pressure vessel using an improved genetic algorithm

As the idea of simulated annealing （SA） is introduced into the fitness function, an improved genetic algorithm （GA） is proposed to perform the optimal design of a pressure vessel which aims to attain the minimum weight under burst pressure constraint. The actual burst pressure is calculated using the arc-length and restart analysis in finite element analysis （FEA）. A penalty function in the fitness function is proposed to deal with the constrained problem. The effects of the population size and the number of generations in the GA on the weight and burst pressure of the vessel are explored. The optimization results using the proposed GA are also compared with those using the simple GA and the conventional Monte Carlo method.     

关联翻译理论对培养英语专业学生翻译能力的启示

本文分析了当前高校英语专业翻译教学的现状与不足,并以关联翻译理论为指导,探讨了其对培养学生翻译能力的启示,即关联理论能够解释译者的创造性,从而能够从理解能力到传译能力两方面更加有效地指导提高学生的翻译实践能力--于翻译中获得原文作者的意图与译文读者期待的最佳关联。     

基于营养动力学的两种群模型的最优控制

讨论了基于营养动力学的捕食．食饵模型的最优控制,得到了使资源管理者获得最大利润并使种群系统持续下去的最优控制率．     

大学英语写作中的过渡语石化与优化输入

在当代语言学论坛中,过渡语的石化现象已经成为大家密切关注的一个话题。它对二语习得的研究有着重要意义,尤其对第二语言写作所产生的影响。本文分析大学英语写作中过渡语石化现象的类型和起因,实际表现,提出在英语写作学习和教学中应该适当进行目的语的优化输入,提高学习者的写作能力,对英语写作教学大有启迪。     

信息与通信产业技术选择对其技术生态环境的作用分析

技术选择对技术生态环境有着重要的影响作用。本文从介绍技术生态环境概念入手，在分析了信息与通信产业技术相关特征的基础上，剖析了信息与通信技术对产业技术生态系统的影响作用，最后，提出了信息与通信产业技术选择与其技术生态环境协同发展的策略。     

Optimal sizing of piezo-actuators for minimum-deflection design of frames under uncertain loads

Optimal piezo-actuator sizes and locations for a frame structure under bending load uncertainty are determined with the objective of minimizing the deflection under worst case of loading. The bending moments generated by the piezo-actuators are used for deflection control, i.e., to minimize the maximum deflection. The frame is subjected to a tip load which lies in an uncertainty domain with regard to its magnitude and direction. The specific uncertain loading studied in the present paper involves a load of given magnitude but of unknown direction, which should be determined to produce the highest deflection. The worst case of loading depends on the size and location of the actuators leading to a nested problem of optimization (design) and anti-optimization (uncertainty problem). Results are given for deterministic and uncertain loading conditions.     

利用MATLAB设计线性二次型最优控制器

本文通过实例介绍用MATLAB设计线性二次型最优控制问题的基本方法，并研究了参数变化对最优控制系统设计的影响。     

红树植物海桑简单重复序列区间(ISSR)条件的优化

海桑(Sonneratiacaseolaris(L.)Engler)是海桑科一种重要的红树植物.为利用ISSR分子标记研究海桑的遗传多样性,对影响ISSR PCR的多个因素,包括Taq酶的用量、Mg2+浓度和dNTP浓度、引物浓度及其退火温度、模板DNA浓度等进行研究,确定了海桑ISSR PCR分析的最适条件:10μLPCR反应体积中,10×buffer(100mmol·L-1KCl,80mmol·L-1(NH4)2SO4,100mmol·L-1Tris HCl,pH9.0,0.5%NP 40)1μL,0.35UTaq酶,2～3.75mmol·L-1Mg2+,300μmol·L-1dNTP,0.3μmol·L-1引物,10ng模板DNA.