几种一维原子链晶格振动特性比较研究

本文从结构、态密度和本征波函数三个方面系统研究了单原子周期链、双原子周期链、无序链、纳米链、Ｆｉｂｏｎａｃｃｉ准晶链和Ｔｈｕｅ－Ｍｏｒｓｅ链六种一维体系的晶格振动特性，给出并讨论了他们的区别和联系。     

拉萨地区2248例乙型肝炎病毒血清学标志分析

目的：探讨西藏拉萨地区乙型肝炎病毒（ＨＢＶ）血清免疫学标记的组合模式。方法 共２２４８例ＨＢＶ血清样本，均以免疫酶联技术（ＥＬＩＳＡ）法检测５项指标。以聚合莲反应（ＰＣＲ）检测ＨＢＶ ＤＮＡ。为表述方便，设定血清ＨＢＶ免疫学标记检测项目第１－５项的排列顺序为（１）乙肝表面抗原（ＨＢｓＡｇ），（２）乙肝表面抗体（抗－ＨＢｓ），（３）乙肝ｅ抗原（ＨＢｓＡｇ），（４）乙肝ｅ抗体（抗－ＨＢｅ），（５）乙肝     

刻度指数族参数的经验Bayes检验的收敛速度

在“加权线性损失”下讨论刻度指数族中参数的经验Ｂａｙｅｓ（ＥＢ）检验问题．利用基于 Ｂｅｓｓｅｌ函数的核估计方法构造了ＥＢ检验函数．在适当的条件下证明了获得的ＥＢ检验函数是渐近最优的具有收敛速度Ｏ（ｎ－１ｌｎ６ ｎ）．最后给出一个满足定理条件的例子．     

Mo_3Al_2C力学及电子性质的第一性原理研究

采用基于密度泛函理论的势平面波方法,在0-50 GPa压力作用下,对立方结构Mo3Al2C的力学性质和电子性质进行了研究。计算表明,计算得到的晶格常数与实验值符合的很好,立方结构的Mo3Al2C晶体在0-50 GPa压力下是稳定结构,块体模量,剪切模量,杨氏模量和不可压缩性随着压强的增加而增大而晶格常数和体积逐渐降低。B/G=2.26,表明这个材料是延性材料。电子性质的分析表明,Mo3Al2C表现出金属性,化学键是共价键与离子键的混合。     

分子束外延具有GaAs／AlGaAs超晶格缓冲层的量子阱材料

采用分子束外延技术（ＭＢＥ）生长了具有ＧａＡｓ／ＡｌＧａＡｓ超晶格缓冲层的单量子阱和多量子阱材料．采用ＧａＡｓ／ＡｌＧａＡｓ超晶格缓冲层掩埋衬底缺陷，获得的量子阱结构材料被成功地用于制作量子阱激光器．波长为７７８ｎｍ的激光器，最低阈值电流为３０ｍＡ，室温下线性光功率大于２０ｍＷ．     

硼氧小分子在铂团簇表面吸附的密度泛函研究

利用杂化密度泛函B3LYP方法,研究了硼氧小分子在铂团簇的表面吸附体系,研究的物性涉及不同自旋下团簇的几何结构、稳定性、电子结构、解离能和平均原子结合能等. 计算结果表明:BO两种原子作为一个分子整体吸附于铂团簇表面,其吸附方式随团簇尺寸的变化而变化;自然布居和Mulliken布居显示,电荷由铂原子转移到BO分子整体. 此外,解离能和平均原子结合能表明四重态Pt4BO的基态结构具有最大的相对稳定性.     

时间序列预测的状态空间方法

时间序列预测的状态空间方法张世英，王艳晖，杨尊琦（天津大学３０００７２）Ｐ，ＣＹｏｕｎｇ和Ｎ，Ｃ，Ｎｇ开发的状态空间预测方法［１］实现了模型参数估计的递推计算，并完全摆脱了Ｂｏｘ一Ｊｅｎｋｉｎｓ时间序列建模的困难，具有很大优点。在Ｐ．Ｃ．Ｙｏｕｎｇ等...     

巨磁电阻材料和物理研究获重要进展

巨磁电阻（ＧＭＲ）效应的应用,是一个从科学发现向应用快速转化的最新例子。ＧＭＲ效应是１９８８年由德国Ｇｒｕｎｂｅｒｇ和法国Ｆｅｒｔ两位科学家的研究组发现的。研究对象是多层薄膜结构：Ｆｅ／Ｃｒ／Ｆｅ三层结构或［Ｆｅ／Ｃｒ］ｎ超晶格（ｎ为周期数）。用分子束外延（ＭＢＥ）方法制备。在外磁场作用下,这种多层结构薄膜的电阻值变化率可达５０％以上,故称为巨磁电阻效应。一年多后,ＩＢＭ公司的Ｐａｒｋｉｎ／小组用磁控溅射法代替昂贵的分子束外延方法制备多层膜,意外发现铁磁层之间的磁矩取向度随中介非磁性层厚度呈振荡…     

管理会计的新进展,企业战略管理的利器———基于活动的成本核算系统

基于活动的成本核算系统（Ａｃｔｉｖｉｔｙ－ＢａｓｅｄＣｏｓｔｉｎｇＳｙｓｔｅｍ，简称ＡＢＣ，下同）是８０－９０年代管理会计的最新进展。不同于传统的成本核算方法，它主张以活动量或事务量为基础来分配大多数间接成本，并识别“成本驱动因素（Ｃｃｓｔｄｒｉｖｅｒｓ）”，因此可以得出正确的成本信息。在现代生产环境下，ＡＢＣ对于企业的生产、经营无疑具有举足轻重的作用，虽然ＡＢＣ的提出主要是着眼于改善间接费用的分配方法，但其意义却决不仅仅限于某种方法的变革，它在有关的成本理论上也有所突破与创新。更为重要的是，它在企业决策和战略管理中具有极大的价值。它不仅可以提供正确的符合管理需要的成本信息，有助于提高成本管理水平，而且为企业进行战略分析提供了一个有力武器，并且可以支持、配合很多新的战略管理方法，如企业过程再造（ＢｕｓｉｎｅｓＰｒｏｃｅｓＲｅ－ｅｎｇｉｎｅｅｒｉｎｇ）′全面质量管理（ＴＱＭ）、持续改良（Ｋａｉｚｅｎ）、ＪＩＴ生产及精简生产（ＬｅａｎＰｒｏｄｕｃｔｉｏｎ）等。在不远的将来，ＡＢＣ将成为企业战略信息系统（ＳＩＳ）的重要基础，取代原有的成本核算系统，发挥越来越重要的作用。     

Eu、N共掺锐钛矿相 TiO2电子结构和光学性质的第一性原理研究

本文基于密度泛函理论的平面波超软赝势法计算了 Eu、N 单掺杂和共掺杂锐钛矿相TiO2的电子结构和光学性质.结果表明,Eu 单掺杂 TiO2体系,可以减少光生电子-空穴对的复合速率;N 单掺杂 TiO2增强了其对可见光的响应;而 Eu/N 共掺杂引起晶格畸变,导致禁带宽度变窄,光吸收带边红移到可见光区,提高 TiO2的光催化效率以促进其更好的利用太阳能.     

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.     

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.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.