一类拟线性抛物型方程弱解的存在性及其有界性证明

在一定有关假设条件下,主要讨论一类带有初边值条件的拟线性抛物型方程的弱解存在性问题及其解有界性问题,利用单调算子理论证明拟线性抛物型方程的初边值条件问题的弱解存在性定理,然后在弱解存在性条件下证明其解的有界性问题。     

时齐马氏链渐进性双曲方程稳定解存在性分析

双曲方程的稳定解分析方法在现代数学应用中具有广泛的意义。采用时齐马氏链进行双曲方程稳定解存在性分析具有模型匹配度高的优点。构建时齐马氏链的双曲波动方程,设计自组织非光滑时滞的双曲系统,结合时齐马氏链渐进性条件下的Lyapunov-Krasovskii泛函算法,对时齐马氏链渐进性条件临界阈值确定,以有效分析双曲方程的稳定解存在性,提高并行算法处理效率,在一阶非光滑时滞系统中得到方向性时齐马氏链函数的分解特征。研究证明,时齐马氏链渐进性条件下,双曲方程存在稳定性解,解向量在有限时间内收敛。     

非交换复微分调控方程边值周期解存在特征分析

非交换复微分调控方程是构建非线性动力系统的基础,对非交换复微分调控方程边值周期解存在特征分析,在高阶累积量矩阵的特征分解和系统设计中具有重要应用价值。构建非交换复微分调控方程的渐进控制闭环系统,估计非交换复微分调控方程的M-P广义逆矩,根据不同场合的需求,进行双边界条件下的平衡点分解,实现边值周期解的存在性分析。用近似线性方法判断其边界平衡点,定义其联合特征函数集合,求解非交换复微分调控方程的两组规范化的第二联合特征函数,得到边值周期解的插值拟合式,证明了交换复微分调控方程的边值周期解具有收敛性。     

一类拟线性Schrdinger方程非平凡解的存在性

本文通过一个变量代换,将一类拟线性Schrdinger方程转化为较为简单的半线性椭圆型方程,并利用山路引理,证明了一类Schrdinger方程在适当条件下非平凡解的存在性。     

半导体中一维拟中性飘移扩散模型解的存在性

本文主要用上下解方法给出了一维拟中性飘移扩散模型局部经典解和整体经典解的存在性，并用能量方法给出了解的唯一性。     

基础科学

关于并行迭代区域分解算法的松弛因子；修理设备可更换且修理有延迟的两不同型部件并联可修系统；关于一类具有时滞的双向联想记忆神经网络的收敛性；分数因子和分数哈密顿图；关于一个Calabi-型曲率流的局部存在性；多维Landau-Lifshitz方程的δ-黏性解。     

拟线性抛物非局部边值问题的摄动问题

讨论了拟线性抛物非局部边值问题(Ⅰ)的摄动问题(Ⅱ)，证明了(Ⅱ)在w^1,2(0，T，V)∩L^2(0，T，V)存在惟一广义解．     

拟线性微分方程边值解的稳定性及收敛性分析

拟线性微分方程边值解的稳定性问题以及收敛性问题是进行时滞系统稳定性控制的关键因素,分析该类微分方程边值解的稳定性及收敛性,首先通过计算微分方程的连续逆平稳的二阶梯度,构建微分方程的连续逆平稳约束模型;其次引入微分方程的逆特征值有稳定解的边界条件,采用时滞关联度特征泛函进行拟线性微分方程的特征解空间遍历,求得具有的拟线性微分方程的边值解;在此基础之上,进行了边值的稳定性和渐进收敛性分析。研究得出,该类微分方程存在边值周期解,在时滞系统控制中具有较好的收敛性。     

一类无穷时滞微分方程正周期解的存在多解性

本文讨论了一类无穷时滞微分方程的正周期解的存在多解性问题,在研究过程中利用了不动点指数定理,算子理论与锥理论,获得了该类方程正周期解的存在性定理,并在此基础上获得了该类方程正周期解的多解性定理。     

正则长波方程的精确行波解

利用行波变换将正则长波方程转化为常微分方程,通过积分把常微分方程约化为初等积分的形式,然后应用多项式完全判别系统法给出正则长波方程的精确行波解。     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

Low doses of a red wine ingredient figh diabetes in mice

Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Molecular motor assembly of a biomimetic system

Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.     

Our Own Devices: Heterotopic Communication, Discourse, and Culture in the Information Society 1

The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests.