铜(Ⅱ)盐催化2,4,6—三溴间甲苯酚聚合反应动力学研究

研究了各种条件下铜(Ⅱ)盐催化2,4,6—三溴间甲苯酚聚合反应的动力学.当[CuCl_2]<0.05mol/L时,r-(k_1k_2)/(k-1)[2,4,6—三溴间甲苯酚][CH_3ONa][CuCl_2];当[CuCl_2>0.05mol/L时,γ=(k_1k_2)/(k-1)[2,4,6 —三溴间甲苯酚][CH_3ONa][0.10-[CuCl_2]);实验所得的速度方程式与铜(Ⅱ) —酚氧配合物中间体形成机理相一致.决定反应速度步骤为2,4,6—三溴间甲苯酚钠与铜(Ⅱ)盐配合物的反应,并且由实验求得了反应速度常数及反应的活化能.     

幼儿园2—6岁儿童受挫缘由探析

对采用观察法获取的北京市122个2—6岁儿童在幼儿园受挫缘由进行分析,结果发现：与教师的矛盾和与同伴的关系问题是引发2—6岁儿童受挫的主要缘由;引发2—6岁儿童受挫的缘由在年龄班上存在显著差异,在性别和幼儿园不同活动上存在极其显著的差异。建议建立良好的师幼关系和同伴关系。根据各年龄班儿童发展的特点和需要强调不同的教育侧重点,对男女幼儿进行双性化教育。合理安排幼儿园的一日活动,促进幼儿园和家庭在挫折教育的观念和方法上的协调一致。     

中学生信息素养标准培养模式的构建

在信息社会里,信息资源良莠不齐,从根本上要求中学生应具备信息需求、信息检索、信息获取、信息使用、信息整合和信息评价方面的能力即信息素养标准。从信息素养以及信息素养标准概念出发,阐述中学生信息素养标准构建的依据,以big6为基础建立中学生信息素养标准模型,提出中学生信息素养标准的实施过程和培养策略。     

硼、糖、钙和DA-6对枇杷花粉管生长的影响

探讨了硼、糖、钙和DA-6处理枇杷花穗对花粉活力和花粉管的影响.结果表明：对照组在气温20.5～26.5℃下花粉活力较低,而且开花1 h后未见花穗上花粉管的伸长;而采用硼、糖混合液处理,或采用硼、糖混合液加钙处理及硼、糖加钙再加DA-6的处理,则提高了花粉活力,显著促进了花穗上花粉管的伸长.     

Residential Location,Job Location,and Wages: Theory and Empirics

I develop a stylized partial on‐the‐job equilibrium search model that incorporates a spatial dimension. Workers reside on a circle and can move at a cost. Each point on the circle has a wage distribution. Implications about wages and job mobility are drawn from the model and tested on Danish matched employer–employee data. The model predictions hold true. I find that workers working farther away from their residence earn higher wages. When a worker is making a job‐to‐job transition where he/she changes workplace location he/she experiences a higher wage change than a worker making a job‐to‐job transition without changing workplace location. However, workers making a job‐to‐job transition that makes the workplace location closer to the residence experience a wage drop. Furthermore, low‐wage workers and workers with high transportation costs are more likely to make job‐to‐job transitions, but also residential moves.     

用VB.NET实现基于以太网的数据采集

文章介绍了利用微控制器STM32和以太网芯片W5100设计的通信方案,并利用编程语言VB．NET进行上位机 软件的编写,完成了计算机与下位机的数据通信及数据采集。实验表明,该方案可以实时显示采样数据,同时也可以将 数据反馈到控制器中,从而控制物体运动形态,准确度高,响应速度快,精度高,较好的实现了预期目标。该系统操作简 单方便,运行稳定可靠,提高了试验测量精度,并节约了试验成本。     

Public policy and the labor market adjustment of new immigrants to Australia

Two separate cohorts of immigrants to Australia are compared in order to assess the potential role of immigrant selection criteria, labor market conditions, and income-support policy in facilitating the labor market adjustment of new arrivals. Although these two cohorts entered Australia only five years apart, their initial labor market outcomes varied dramatically. The results indicate that changes in immigration policy may have led to increased human capital endowments that in turn resulted in higher participation rates and reduced unemployment. At the same time, improvement in Australian labor market conditions and changes in income-support policy over the 1990s – which most likely altered the returns to human capital – were probably instrumental in reinforcing the effects of tighter immigrant selection criteria. As much as half of the fall in unemployment rates among women and one third the decline among men appears to have occurred as the result of changes in the returns to demographic and human capital characteristics. Responsible editor:Christoph M. Schmidt     

An evaluation of the Tokyo Round trade agreement using general equilibrium computational methods

An empirically based general equilibrium model involving the United States, Japan, the (nine-member) EEC, and a residual rest of the world is used to evaluate the Tokyo Round trade agreement negotiated under the GATT. Equilibria for post-Agreement policy regimes are computed and compared to a pre-Agreement equilibrium. Results indicate small aggregate welfare impacts but more significant terms of trade effects. Losses seem likely for Third World countries due to an adverse terms of trade change. Under some assumptions the changes in NTB codes produce more significant effects than the tariff cuts in the Agreement.     

Policy modeling of foreign exchange rates

This paper is neither a complete survey of empirical work on exchange rate determination, nor a review of the ballooning volume of theoretical models. It is instead an attempt to classify the main alternative approaches to modeling exchange rates. I shall concentrate on approaches that can be used to assess the effects of alternative policies. There will be four further sections in the paper. The first three sections will each deal withthe structure, empirical support, and policy consequences of three main types of model: purchasing power parity models emphasizing the close and immediate relation of goods markets; interest rate parity models emphasizing the close and immediate international linkage of markets for financial assets; and structural balance-of-payments models that do not assume either of the above linkages to be so strong and immediate as to eliminate the other, and that hence require separate (but interdependent) modeling of trade and capital linkages in the determination of exchange rates. Each of these main categories has many rather distinct models within it, and some models are not easily classified into one of the three categories; I hope that the three-way split will nevertheless serve to make some distinctions that are important for policy modeling.In the final section I shall try to summarize the available model results that pertain to national and international policy choices under a system of more flexible exchange rates, and then to suggest where more or better model building might usefully increase the amount of information available to guide policy decisions.     

情态显隐性的语用分级与CET4/6阅读语篇特征研究

情态表达言者的判断、态度等含义,具有显隐性和主客观性。根据情态的四种取向,本文对近十年的CET4/6阅读中的短文语篇、正确选项和干扰项的语篇作了分析,试图发现各自的情态特征和相关性,以提高阅读理解的效率。