W_6Mo_5Cr_4V_2高速钢钢丝高频热塑性的改进

分析影响W_6Mo_5Cr_4V_2高速钢钢丝高频热塑性的因素,解决轧制钻头轧裂问题。试验结果表明:钢丝的S含量低高频热塑性好,同时Mn/S高,高频热塑性好;碳化物颗粒小(大颗粒碳化物尺寸≤6μm)并且拉裂程度小钢丝高频热塑性好;冷拔钢丝道次减面率控制在20%以下,高频热塑性好。     

三元阴极材料的电性能及其在镁固态电池中的应用

合成的三元阴极材料,经X射线粉末衍射鉴定,其组成为Mo_(0.8)V_(5.2)O_(13),测得该材料的室温电导率为10~(-4)(Ωcm)~(-1)数量级,求得在298～363K之间的电导激活能为0.175eV。用这种阴极材料组装成全固态Mg/Mo_(0.8) V_(5.2)O_(13)电池,其开路电压为2.0V。在复合阴极材料中加入适量的添加剂(如氯化物等),电池具有良好的储存性能及放电性能,当负载为50kΩ时,从1.4V起分段出现平台,各持续4～5天不等。电池的放电容量为28.5 mA·h,比能量为75.7W·h/kg。这种固态电池的阴极利用率较高,循环寿命较长,并且能够经受深度放电。最后对导电机理作了探讨。     

螯合配体构建多酸配合物的合成及晶体结构

利用水热合成技术合成了一个螯合配体构建的多酸配合物[Ni(2,2'-bipy)_3][Mo_6O_(19)],并通过X-射线单晶衍射对其进行了结构表征。化合物由Lindqvist型多钼酸阴离子[Mo_6O_(19)]~(2-)和[Ni(2,2'-bipy)_3]~(2+)配阳离子组成。该化合物属于单斜晶系,P 2_(1/n)空间群,a=12.3451(6)?,b=18.9835(10)?,c=17.2109(10)?,α=90°,β=101.166(5),γ=90°,V=3957.1(4)?~3,Z=4。     

金属玻璃断裂韧性的研究进展

金属玻璃由于有特殊的结构,它和传统的晶体材料相比较而言,具有不一样的变形和断裂的方式,它的发明和研究历史悠久,是研究材料科学和凝聚态物理问题方面中重要的模型,具有比较广泛的应用前景。本文通过制备出Zr_(41.25)Ti_(13.75)Ni_(10)Cu_(12.5)Be_(22.5), Ce_(68)Al_(10)Cu_(20)Co_2和Fe_(41)Co_7Cr_(15)Mo_(14)Y_2C_(15)B_6这三种金属玻璃,利用大量的压缩实验及其测试,从而描绘出应力应变曲线,说明不同种类的金属玻璃的断裂韧性特征,同时也对材料力学的有关知识进行归纳总结。     

哈夫曼树Hufferman构成原理应用及其数学证明

哈夫曼树又名最优二叉树,是一种构造带权路径长度最短的二叉树。所有树的带权路径长度,即是树中所有的叶子结点的权值乘以其到根结点的路径长度(若根root结点为0层,叶结点到根结点的路径长度就是叶结点的层数)。二叉树的带权路径长度可记为WPL值=(W_1~*L_1+W_2~*L_2+W_3~*L_3+…+W_n~*L_n),n个权重值W_i(i=1,2,...n)构成一棵拥有n个叶结点的二叉树,其相应的叶结点的路径长度为L_i(i=1,2,…,n)。能够证明哈夫曼树的WPL的取值是最小的。     

Cr_2AlC掺Si的强化机理

主要应用第一性原理的方法来研究Cr_2Al1-xSixC(x=0,0.056,0.111,0.167)的结构、弹性和电学性质,以便弄清Cr_2Al1-xSixC的固溶强化机制。理论计算的晶格常数(a和c)和实验得到的结果非常一致(误差小于2%)。理论计算表明Cr_2Al1-xSixC掺入Si之后体积模量会增大。通过研究Cr_2Al1-xSixC的电子结构表明:由于Cr和Si键的杂化比Cr和Al之间的杂化更强,这就促进了固体的掺杂。因此导致电荷分布更加密集,体积模量更大和机械性能更好。     

基于压电阵列的能量转换发光演示器件

利用正压电效应发电,控制电路供电,光电二极管(LED)组块发光,研制了一种基于机—电—光能量转换发光的演示器件。使用数字示波器和定值电阻(50Ω)探究了发电模块输出电压随单层陶瓷片数及模块层数之间的定量关系。当双手有规律地按压时,单片陶瓷整流前的输出电压峰值(V_(pp))约为15.58V,随着片数的增加,V_(pp)逐渐降低,当片数增加到49片时,单层模块的V_(pp)约为6.95V。将四层发电模块单独整流,并联叠放,压电阵列的V_(pp)约3.22V。当连接50Ω定值电阻负载时,发电模块的输出峰值功率可达0.5mW。演示时,负载连接LED组块(并联200个红光LED),器件可在双手按压下呈现出明显的发光现象。     

低温平板式脱硝催化剂的制备及其性能研究

平板式脱硝催化剂主要成分为不锈钢网格、TiO_2、V_2O_5和MoO_3。该文主要对低温条件下平板式脱硝催化剂制备及其性能进行了研究与探讨,主要采用BET、催化剂反应性能试验装置等进行了表征和测试,结果表明,通过改变煅烧温度区间的时间,改性后的平板式脱硝催化剂的性能达到了59.1m/h(365℃)和43.3 m/h(220℃),由此可以证明,该改性的方案明显改变了V_2O_5的分散性,且有利于微孔的形成,大大提高了平板式催化剂的低温下的活性。     

基于专利信息的人工智能技术创新网络图谱研究

本文使用德温特创新专利引文索引数据库提供的人工智能相关专利数据(2010—2020年),利用知识图谱软件Citespace绘制人工智能技术创新网络图谱,识别出AI创新关键路径及重要节点企业/科研机构、中国人工智能领域最有发展潜力的创新主体和重要创新主体,并对其创新合作特征进行分析。结论如下:(1)2010—2020年人工智能关键路径及演化呈现四大特征;(2)AI创新关键路径重要节点企业/科研机构有15家;(3)AI最具潜力的创新主体有华为等10家企业,以及中山大学等15家高校/科研院所;(4)AI重要创新主体有腾讯等10家企业,以及电子科技大学等10家科研机构。     

退火处理对Mn掺杂TiO2粉末样品结构及磁性的影响

利用溶胶-凝胶法制备了Ti0.97Mn0.03O2胶体,在空气中退火处理,利用X射线衍射(XRD)测量了样品的结构特性,电子能谱仪(XPS)测量了样品的元素价态,并且利用振动样品磁强计(VSM)测量了样品的磁特性。研究显示900℃退火处理的样品表现出铁磁性,饱和磁化强度为0.027emu/g。研究表明样品既表现出磁滞区域又表现出顺磁性,可能是因为Mn以Mn4+和Mn3+替代了Ti4+,其中Mn4+替代Ti4+产生铁磁性,Mn3+替代Ti4+产生顺磁性。     

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.