以滑移机理探讨色谱分析的塔板数

以滑移色谱机理弥补塔板理论的不足，滑移色谱机理的色谱流出曲线函数可更真实地表达实际色谱流出曲线。在计算色谱柱塔板数时，应区分色谱柱塔板数和色谱峰塔板数（是由实际色谱峰形得到的，在色谱过程中实际发生的），因色谱柱塔板数与色谱峰塔板数是不同的概念。推导出色谱拄塔板数与色谱峰塔板数之间的关系式。该关系式成功地解释了通常色谱峰显著拖尾的原因。丙酮在GDX-101上的吸附焓△H=-3.6k．J／mol.     

旋流塔板上气流场的计算

旋流塔板上气流场的计算王家德陈建孟（浙江工业大学环境科学与工程研究所杭州３１００３２）旋流塔板是一种用于传质、传热、除尘及除雾等过程的通用设备［１］．目前对其气流场的研究限于实验测定，本文采用数值计算方法对该塔板上气流场进行预测．对于板上作旋转运动的...     

基于零维模型的液滴蒸发建模和仿真

考虑到液滴蒸发过程中与环境的压差关系,液滴直径对雾化的非连续性影响,对此引入克努森修正系数,可以降低对蒸发过程数值仿真的难度系数。基于零维模型前提下,建立气液两相的质能模型。基于此模型,研究了空气温度、喷雾温度与气液体积比对加湿性能的影响。     

水滴撞击冷壁面的铺展和凝固过程研究

液滴撞击壁面过程中对铺展与冷却凝结的主要影响因素有液滴撞击速度、液滴温度。此外,液滴的大小也对撞击后凝固形状所需时间产生影响。本文通过计算机模拟,研究不同直径的水滴在相同其他条件下撞击冷壁面的效果。研究结果表明,水滴直径对水滴铺展及凝固都有显著影响。     

科技转移

正特殊物系精馏新技术技术简介:本技术成功解决了化工、石化等行业中高粘度、易自聚等特殊物系的精馏。通过对塔板上流体力学的研究与数学模型的建立,确定在塔板上开设一部分导向孔。从导向孔中水平喷出的气体传递给塔板上液体的动量与液体克服前进阻力所需要的动量相等,使塔板上液流呈"活塞流"流动,从而降低液面梯度,减少液相返混,提高传质效率,     

高频热等离子体中液滴传热传质过程研究

建立了单个液滴在高频感应热等离子体中内部传热传质的数学模型,考虑了希尔球形涡的影响,模拟了液滴在不同入射尺寸下的内部传热传质变化过程。结果表明,随着液滴入射尺寸的增大,液滴表面溶质质量分数到达饱和状态所需时间缩短,且其内部环流的对流作用占主导因素,使得溶质在液滴表面集中,易形成浓度集中的表面薄层。     

芯片上的实验室

美国科学家成功地使微米尺寸的液滴悬浮在微磁体之间，并操纵液滴互相融合发生反应，制成了世界上最小的“化学实验室”。由于反应物的体积极其微小，即使是非磁性的物质，也可以在芯片磁场中悬浮起来完成反应。理论上，几个这样的芯片就可以完成一个复杂实验室的功能。这一操纵微小物体的技术可能在医药、化学、     

基于电润湿的液滴捕获与分选方法

在微流控芯片中制作了进行电润湿操控的微电极。利用微流控芯片的微沟道和电润湿的作用,将高通量和精确控制这两个优点结合起来。研究了液滴的半径,移动速度和电极结构与捕获电压之间的关系,用112 V电压捕获了半径为60μm的液滴。利用电润湿实现了对液滴的分选,发现液滴的半径,移动速度和驱动的方式,会影响分选所需的电压。利用42 V电压实现了对半径为60μm的液滴捕获。利用电润湿作用,我们成功将包裹He PG2细胞的海藻酸钠液滴分选出来。     

唐山中润化工甲醇装置精馏单元技术改造

总结了唐山中润化工焦炉煤气制甲醇装置精馏单元加压塔产量下降,能耗提高的问题,提出通过用New-VST塔板(圆罩)代替原来的CJST塔板(方罩)对加压塔内件进行改造。结果表明,改造后能耗降低,每年可以节省4~7万吨蒸汽。     

基于CFD分析的射流流场数学模型建立

介绍了在CFD软件的条件下研究液体喷射雾化过程中从喷嘴喷射出来的液体未雾化成小液滴的初始射流过程的数学模型的建立分析综述。介绍了CFD软件的应用并概括了一般射流流场模型建立的进本步骤及数值求解过程中用到的方法和物理理论,为进一步研究和优化液体的射流雾化过程提供研究方法和参考依据。     

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.     

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.     

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