如何培养学生的软件开发经验

计算机软件的发展日新月异,对于初学者来说应该如何下手,这就需要教师们组织好教学内容和开设课程的顺序,教会学生们计算机软件编程的入门方法,培养他们软件编程的好习惯,丰富同学们实际开发软件的经验,为学好计算机打下良好的基础。     

论毛泽东同志在建党前完成思想根本转变的双重原因

在中国共产党成立之前,从"五四"运动到一九二O年夏天是毛泽东同志思想飞跃发展的关键时期。在这个时期,他完成了思想的根本转变,从一个具有初步共产主义思想的知识分子发展为坚定的马克思主义者。作者从客观影响和主观努力两个视角分析了毛泽东同志在建党前完成思想根本转变的双重原因。     

An R2criterion based on optimal predictors

The predictor that minimizes mean-squared prediction error is used to derive a goodness-of-fit measure that offers an asymptotically valid model selection criterion for a wide variety of regression models. In particular, a new goodness-of-fit criterion (cr²) is proposed for censored or otherwise limited dependent variables. The new goodness-of-fit measure is then applied to the analysis of duration.     

镓铟砷磷 磷化铟掩埋新月形激光器

本文研究了一种新型的1.3μm InGaAsP/InP掩埋新月形(BC)激光器。采用两次液相外延(LPE)技术形成掩埋双異质结构(BH),p-n-p-n电流阻挡结构和窄有源区。该器件在室温连续工作条件下的阀值电流低达15mA、基横模、单面输出功率大于12mW。     

Microdata Access and Labor Market Research: The U. S. Experience

Summary: The paper illustrates the value of broad researcher access to survey and administrative microdata using examples drawn from the U. S. experience, outlining how analyses of trends in earnings inequality, poverty and employment dynamics using such data have benefited policy makers and contributed to improvements in statistical agency data products. Methods of facilitating researcher access, including the release of public use files, the use of licensing agreements, and the establishment of research data centers, are discussed. * The author thanks Anne Polivka, Marilyn Seastrom and two anonymous referees for helpful comments on an earlier draft of the paper.     

Dynamic factor models

Summary Factor models can cope with many variables without running into scarce degrees of freedom problems often faced in a regression-based analysis. In this article we review recent work on dynamic factor models that have become popular in macroeconomic policy analysis and forecasting. By means of an empirical application we demonstrate that these models turn out to be usefu in investigating macroeconomic problems.     

多普勒测速技术的新进展

七十年代以来,随着对固体材料冲击波的研究,激光多普勒测速技术有了新进展:广量程和高解析度.最早用于冲击波研究的是位移干涉仪,其局限性是被测速度不能超过200m/sec.为了扩大量程,继而研制出速度干涉仪,从方法上解决了高速度的测量.但速度干涉仪对测速物体表面有磨光的要求,这也限制了它的实际应用.解决的方法是引入广角迈克尔逊干涉仪,以利用物体自然表面的漫射光,这就是对任何反射物的速度干涉仪系统,即VISAR.VISAR是目前激光多普勒测速仪器中最具代表性的一种,本文作了重点介绍.     

人工物技术创造过程中的隐蔽场所理论

作者借鉴系统科学研究的方法,对人工物的技术创造过程及中心法则进行比较分析,指认二者为具有逻辑相应性的同态过程,以中心法则为技术创造的同态概念模型进行分析,反应出信息要素的表达在产品使用价值构成中的关键地位,进而揭示出使用价值的生成存在一个不同于产品制造的场所——一个在以往被忽略了的隐蔽场所。     

激光超声的光学零差探测

激光巨脉冲在金属铝块上产生超声波,由光学零差探测得到超声引起的后表面位移的波形。文中分析了探测信号与位移的关系,导出了系统灵敏度公式。用激光超声测得铝块厚度与实际值很好地吻合,同时测出了系统的最小可探测位移。     

Three models of OPEC leadership and policy in the aftermath of Iran

Collapse of the Shah's regime has transformed Iran's attitude regarding oil production policy. The nature of OPEC leadership is changing as well. Three models examine the nature of this leadership inside OPEC: (1) the conventional price leadership model, (2) a model emphasizing a concept of egalitarian leadership, and (3) a team model composed of coalitions. The three models establish the limits within which OPEC leadership is exercised. A composite model drawing upon all three sets of results suggests that Saudi Arabia shapes cartel policy not by itself, but through a dominant coalition of states. For most of the period 1969–1978 this coalition has been stable. Following the unsettling changes of 1973, cooptation of Iran into the dominant coalition in 1974 was an important step in achieving a new level of stability. But during the turbulence of regime transformation in Iran, the nature of the governing coalition appears to have changed. One consequence may be that in the future Saudi Arabia will yield more willingly to arguments heard within OPEC on behalf of upwards price pressure, especially in an atmosphere of growing political isolation and overall tight supply.