共查询到20条相似文献，搜索用时 62 毫秒
1.
磺化麦草碱木质素热分析动力学研究 总被引：1，自引：0，他引：1
为研究磺化碱木质素在高温条件下的热稳定性能，实验采用热重－红外分析(TG-IR)和差示扫描量热分析(DSC) 研究了磺化麦草碱木质素在非氧状态下热分解反应的动力学过程。利用多升温速率法Kissingr法和Ozawa法，分别计算了磺化麦草碱木质素热动力学方程中的表观活化能(Ｅ)和频率因子lnA，分别为118.3 kJ•mol-1、121.46 kJ•mol-1；20.40min-1、15.92min-1；利用Kissingr法计算了热动力学方程的反应级数是1.8。 相似文献
2.
李宏 《科技成果管理与研究》2011,(5):63-65
针对原有分相式的阀基电子设备进行了新的研究,将三相的阀基电子设备集中为两个单元,分别为光电触发单元和阀监控单元,介绍了新的阀基电子设备的结构、工作原理,分析了改造后的效果。 相似文献
3.
一种新颖的高阶全极点CC高通滤波器 总被引：8，自引：0，他引：8
提出了一种高阶全极点ＣＣ高通滤波器的设计方法．用该方法对二～七阶最平坦型Ｂｕｔｔｅｒ－ｗｏｒｔｈ高通滤波器进行了设计和ＰＳＰＩＣＥ模拟分析,结果与理论分析吻合,表明本文所提方法的可行性． 相似文献
4.
本文以对－二甲苯为起始物合成了对苯二甲基双三苯基磷氯化物,再进一步对硝基苯甲醛反应,合成１,４－二（４－硝基苯乙烯基）苯。对该化合物进行了元素分析,红外光谱鉴定,确定了其组成和结构,可将该化合物的还原产物与不同的偶合剂偶合成不同的偶氮颜料,这些颜料可用作有机光导体的电荷发生材料。 相似文献
5.
本文研究了在阳离子表面活性剂溴化十六烷基三甲铵存在下,９—（３,５一二溴）水杨基荧光酮与铝的显色反应条件和光度性质。实验结果表明,该体系可允许硫脲抗坏血酸、草酸钠等掩蔽剂存在,可用于测定铜合金、合金钢中微量铝。方法简便、快速、灵敏度高。 相似文献
6.
用化学还原法制备了非晶态合金催化剂Ｎｉ－Ｂ、Ｃｏ－Ｂ和Ｃｏ－Ｎｉ－Ｂ．合金的非晶性质由Ｘ射线衍射（ＸＲＤ）及透射电子显微镜（ＴＥＭ）鉴定．组成用电感耦合等离子发射光谱（ＩＣＰ）分析．在高真空程序升温脱附质谱（ＴＰＤ－ＭＳ）装置上研究了ＣＯ、Ｈ２在三种催化剂上的吸附及ＣＯ和Ｈ２的表面反应（ＴＰＳＲ）．发现ＣＯ和Ｈ２在三种催化剂上分别有二种和一种吸附态，吸附强度和二种吸附态的数目在不同合金上有较大差异．ＣＯ加氢反应的主要产物是ＣＨ４、ＣＯ２和Ｈ２Ｏ，其中ＣＯ在催化剂表面上的解离是反应的控制步骤． 相似文献
7.
非晶态合金可用作催化新材料．本文用ＸＰＳ方法表征了Ｎｉ－Ｂ和Ｎｉ－Ｃｏ－Ｂ超细非晶态合金，并结合其对ＣＯ加氢的反应性能，初步解释了表面物种及状态与催化活性的关系 相似文献
8.
研究在pH3．5～4．0、沸水浴中加热的奈件下，Cr（Ⅲ）与EDTA和溴代十六脘基三甲基胺（CTMAB）生成紫红色三元络合物，其最大吸收波长为562nm，而在此条件下，Cr（Ⅵ）不反应，Cr（Ⅵ）ej最大吸收波长为352nm。利用Ccr（Ⅲ）-EDTA-CTMAB络合物和Cr（Ⅵ）最大吸收波长的差异，建立了双波长分光光度法同时测定Cr（Ⅲ）和Cr（Ⅵ）的方法。该方法简单、快速、准确。 相似文献
9.
基于DW与OLAP新技术的企业决策支持系统分析 总被引：1，自引：0，他引：1
基于数据仓库(Data Warehouse，DW)和联机分析处理(On-line Analytical Processing，olAP)技术相结合建立的辅助决策系统是企业决策支持系统(corporatin Decision Support Systenl，CDSS)的新形式。本文在分析这两种关键技术的特点及对CDSS的影响的基础上，提出了建立基于数据仓库与联机分析处理技术的企业决策支持系统的一般开发过程。 相似文献
10.
ＴＥ１０３单模腔是微波烧结系统中应用最广泛的单模谐振腔，品质因数Ｑ值是度量腔体对外部激励响应的尖锐程度，是对烧结影响最大的谐振腔基本参量。采用扫频法测量，并从理论上讨论了在谐振腔中分别插入直径为８ｍｍ的不同棒状介质后，以及不同孔径、不同厚度耦合膜片对Ｑ值的影响。 相似文献
11.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
12.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
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. 相似文献
13.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
14.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US 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 the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
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. 相似文献
15.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
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. 相似文献
16.
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. 相似文献
17.
Puay Tang 《The Information Society》1998,14(1):19-31
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. 相似文献
18.
Milton Mueller 《The Information Society》2001,17(3):151-163
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. 相似文献
19.
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.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
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. 相似文献
20.
Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献