网络智力与技术资源的共建共享--北京高校网络图书馆虚拟参考咨询系统项目建设

北京高校网络图书馆开发了具有地域特色的网络合作化虚拟参考咨询系统,该系统利用多媒体会议协议、实时多点数据通讯网络协议标准和共享技术,以及HTTP隧道技术等技术手段实现了在线咨询的多项功能。文章就此系统的产生背景、建设目标、功能和技术特点等进行了阐述。     

Two for the price of one?: Additionality effects of R&D subsidies: A comparison between Flanders and Germany

We empirically test whether public R&D subsidies crowd out private R&D investment in Flanders and Germany, using firm level data from the Flemish and German part of the Community Innovation Surveys (CIS III and IV). Both the non-parametric matching estimator and the conditional difference-in-differences estimator with repeated cross-sections (CDiDRCS) clearly indicate that the crowding-out hypothesis can be rejected: funded firms are significantly more R&D active than non-funded firms. In the domain of additionality effects of R&D subsidies, this paper is the first to apply the CDiDRCS method.     

Estimating the causal effect of R&D subsidies in a pan-European program

We investigate the effect of Europe's largest multilateral subsidy program for R&D-performing small and medium-sized enterprises. The program applied a specific budget allocation rule, referred to as Virtual Common Pot (VCP), which is designed to avoid cross-subsidization between participating countries. This rule creates exogenous variation in funding status and allows us to identify the causal effect of public R&D grants on firm growth. In addition, we compare the program's effect under the VCP rule with the standard situation of a Real Common Pot (RCP), in which program authorities allocate a single budget according to uniform project evaluation criteria. Our estimates suggest that R&D grants had no average effect on job creation and sales growth, but treatment effects were heterogeneous and positive for high-quality projects. Under an RCP the program would have created 53% more jobs and 48% higher sales.     

Partly risky,partly solid – Performance study of public innovation loans

In this paper I attempt to measure the ability of a Norwegian publicly subsidized loan program to identify innovative firms that are victims of market imperfections. I apply three complementary control groups, which all have in common that they address specific unobservable characteristics of the program participants. The program participants perform better on a variety of growth measures compared to the firms rejected by the program. Compared with firms that receive private credit financing, I do not find that the program participants perform better in the upper quantiles of the contingent performance distribution despite a lower survival rate. The latter result suggests that the program does not seem to succeed in identifying a target group of firms with a sufficiently high growth potential. Firms with innovation loans are not outperformed by venture portfolio companies with respect to sales growth. The venture portfolio companies do, however, have higher survival rates as well as stronger growth in employment and assets. The latter result possibly indicates that the venture portfolio companies are more likely to succeed in the long run. The overall results indicate that the selection competency of the bureaucrats administrating the program is at level with that of private banks, and possibly also of that of venture funds. Still, in order for the program to provide the same level of welfare improvement as regular business credit provided by the private market, I find that the positive externalities from the program must be sufficiently large to compensate for the direct public subsidy element including risk adjusted return on equity and social costs of public funds.     

一元酸溶液氢离子浓度计算的简易方法

现行分析化学教材中H^ 浓度的计算采用公式法,计算公式是根据不同条件近似处理得到的,在这些公式中,有的适用于浓酸,有的适用于稀酸;有的适用于弱酸,有的适用于极弱酸。在实际计算中,选择公式比较困难,这是因为难以判断给定的酸是浓酸还是稀酸。是弱酸还是极弱酸。本文用定量的方法将溶液分为浓溶液和稀溶液两大类,并给出分别适用于浓溶液和稀溶液的计算公式。应用此公式可以十分方便地计算不同浓度条件下的一元酸(强酸、弱酸和极弱酸)的[H^ ]。与现行公式相比,文中公式具有计算简便、结果可靠、使用范围广的特点。     

柠檬酸溶胶凝胶法制备铈锆固溶体的物性和氧化还原特性研究

以柠檬酸作为胶凝剂,采用溶胶凝胶法制备了一系列CeXZr1-XO2复合氧化物,分别经600℃和900℃焙烧,应用XRD检测,发现均已形成铈锆固溶体。并应用BET、XRD和TPR对其表相、晶相结构和氧化还原性质进行了分析,发现随着固溶体中铈比例的增加,固溶体稳定性降低;其储氧量测定显示铈锆固溶体用作三效催化剂助剂的最佳比例为1：1。经900℃高温焙烧以后,固溶体晶粒增大不明显,表明本方法适合制备高比表面积和高储氧量的铈锆固溶体;TPR还原峰温度降低,推测可能在于柠檬酸络合物完全分解所致。     

超标准数学的兴起

本文从数理逻辑、数系扩张、理想元素、超有限集覆盖法、模拟客观世界乃至教学原则等方面简论超标准(非标准)数学的重要意义.本文旨在说明超标准分析在理论上是别开生面的课题,实用上是独辟蹊径的研究.     

Developing children's self-efficacy and skills: The roles of social comparative information and goal setting

How social comparative information and specific, proximal goals influence children's skillful performance and percepts of self-efficacy in the context of arithmetic competency development was explored. Low-achieving children in arithmetic received instruction in division and practice opportunities. One group was provided with social comparative information indicating the average number of problems solved by other children. A second group worked under conditions involving a goal of completing a given number of problems. A third group received both treatments, and a fourth group received neither treatment. Results yielded a significant main effect on perceived efficacy due to proximal goals. Children who received both goals and comparative information demonstrated the highest level of division skill. Results suggest exploring in greater detail how children weight and combine multiple sources of efficacy information.     

Theme and prose comprehension: Understanding or depth-of-processing?

Context orientation and depth of processing were tested as possible explanations for thematic organization. In the first experiment, the process of searching for the theme of concrete versions of prose passages by undergraduates was detrimental to subsequent recall. On the other hand, theme statements facilitated recall when provided prior to concrete as well as abstract versions of each passage. Finally, the theme search process with the abstract versions was beneficial only when the correct theme was identified. A second experiment provided further data supporting the comprehension hypothesis for theme organization when precise, instructor-generated theme statements were used instead of learner-generated themes.     

乙炔中的π键与卤化氢相互作用的理论研究

采用从头计算理论,对C2H2中的π键与HX（X=F,C1,Br,I）形成的典型X-H…π键复合物进行了系统的研究．对复合物几何结构进行了优化,计算各体系的结合能和BSSE,并对计算结果在几何结构、电荷分布及静电势和能量上进行分析．研究结果表明,C2H2…HX（X=F,Cl,Br,I）复合物体系随着卤素原子序数的递增,键长等参数都出现了周期性增加,复合物的结合能在整体上呈现减小的总趋势,与之对应的X-H…π相互作用减弱．