Effect of silver addition on superconductivity in the Bi1.6Pb0.4Sr1.6Ca2Cu3O10−y system

Silver/superconductor composites containing 0 to 80 vol% silver have been prepared and their properties determined. Optimum heat treatment at sintering temperatures ( 800° C) under low oxygen pressures produces material with high critical current density and improves physical properties. Magnetic susceptibility measurements have been found to be consistent with resistivity results. In order to retain a single high-T _c phase with increasing silver content, decreased oxygen partial pressures are required. Using the normal-state resistivity of these composites, a percolation threshold at a silver volume fraction of 43% was observed, while zero resistivity measurements show that a continuous superconducting network can be obtained with up to 80 vol% silver. The critical current density of 21 vol% silver-doped samples was found to be 1520 A cm^–2 at 77.3 K, compared to 260 A cm^–2 for an undoped sample.     

非晶态化学镀Ni-Sn-P合金镀层变温晶化的研究

研究了非晶态Ni-Sn-P合金镀层的变温化过程,由实验得出Ni-Sn-P合金约在350℃开始晶化,450℃左右晶化结束,并测得Ni-Sn-P合金变温晶化激活能为233KJ·moL~(-1)。     

一种基于角色和数据项的访问控制方式

当今社会,随着信息和通信技术的飞速发展,数字信息正在被广泛使用,为了进行数据分析以支撑基于信息的决策,政府、社会机构、公司和个人都可能会收集一些涉及个人的信息数据,然而伴随着大数据资源的正在进行越来越广泛的整合、分析和利用,使得数据治理问题,特别是数据隐私保护问题也越来越被人们重视,成为大数据研究的一个重点。本文针对如何保证数据资源在使用过程中的安全访问控制问题,在主流的基于角色的访问控制方式的思路之上进行了扩展,提出了一种基于角色和数据项的访问控制方式,即在数据库中增加角色对数据表中每一项的访问权限表。实践结果表明,与目前主流的几种访问控制模式相比,实现了对数据的精细化管理,对不同角色的用户访问实现了数据可控,对大数据环境下信息系统的数据隐私保护具有一定的指导意义。     

18世纪晚期市民阶级在德国文化中的自我塑造:《奢侈与时尚期刊》研究

本文通过研究<奢侈与时尚期刊>来分析18世纪德国市民阶级的自我塑造.它宣扬奢侈品消费加速了经济与社会的发展,也为文化进步和国家民族富裕提供了动力.它主要关注私生活里的文化与社会自身的构建,并帮助市民阶级进行自我塑造且与其他阶级进行区分.它还阐述了时尚与奢侈品消费的重要性与必要性,并驳斥了神学与道学将时尚视为虚荣及道德缺陷的偏见.它认为作为文化差异的一部分,服装特色的区分成为一种衡量人民与国家成熟与否的标尺.时尚发挥了视觉艺术的功能,甚至于也是一种行为艺术.此外,时尚还与身体复杂地联系在一起,两者缺一不可.     

A recognition method of vibration parameter image based on improved immune negative selection algorithm for rotating machinery

To overcome the limitations of traditional monitoring methods, based on vibration parameter image of rotating machinery, this paper presents an abnormality online monitoring method suitable for rotating machinery using the negative selection mechanism of biology immune system. This method uses techniques of biology clone and learning mechanism to improve the negative selection algorithm to generate detectors possessing different monitoring radius, covers the abnormality space effectively, and avoids such problems as the low efficiency of generating detectors, etc. The result of an example applying the presented monitoring method shows that this method can solve the difficulty of obtaining fault samples preferably and extract the turbine state character effectively, it also can detect abnormality by causing various fault of the turbine and obtain the degree of abnormality accurately. The exact monitoring precision of abnormality indicates that this method is feasible and has better on-line quality, accuracy and robustness.     

Fabrication of niobium doped Pb（Zr, Ti）O3 fibers by viscous polymer processing

A technique based on viscous polymer processing （VPP） was described, which can produce high ceramic content green fibers. PZT-5 ceramic powders were ball milled to get high dispersibility. The slurry prepared for VPP was a composition of PZT-5 powder, PVA binder and glycerin. High ceramic content PZT-5 fibers were extruded with the slurry. The results show that the ceramic powders have fine mean particle size of 0.54 pan, high specific surface area of 3.55 m^2/g and zeta potential of 8.81 mV after 16 h milling. The fibers sintered at 1 280 ℃ for 4 h have pure perovskite structure and grains of 2-5 μm in size, with little pores or cracks. The ultimate tensile strength of sintered fibers is up to 13.84 MPa compared with 2.88 MPa of green fibers. The remnant polarization （Pr） and coercive field （Ec） of the fibers are 50.65 μC/cm^2 and 2.45 kV/mm, respectively. This fiber can withstand an electric field of 9 kV/mm higher than the ceramic （5 kV/mm）, which shows high directional and compact qualities.     

高铝锌基合金直齿圆锥齿轮的挤压铸造工艺

利用挤压铸造技术生产高铝锌基合金直齿圆锥齿轮，齿面精度能够得到保证。适用于工作环境较好，载荷不是很大条件下的高铝锌基合金直齿圆锥齿轮，可减少设备投资、减少工序工时，从而大大降低生产成本，具有很高的经济效益和社会效益。     

Power of the Swipe: Why Mobile Websites Should Add Horizontal Swiping to Tapping,Clicking, and Scrolling Interaction Techniques

Horizontal swiping has become a common interaction technique on smartphones, yet many mobile websites do not incorporate this functionality, instead requiring users to scroll down or click on buttons, arrow keys, and other hotspots. This is perhaps because user studies comparing swiping with other interaction techniques are scarce. An experiment was conducted (N = 252) to inform this issue by investigating whether and how adding the swiping functionality to a tap-only mobile website influences users’ intentions to use the website. The data revealed that the addition of swiping technique positively affected behavioral intentions to use the website. Perceived enjoyment was a key variable that explained this effect. These findings have design implications for mobile websites.     

A two-time-scale load balancing framework for minimizing electricity bills of Internet Data Centers

Internet Data Center (IDC) is one of important emerging cyber-physical systems. To guarantee the quality of service for their worldwide users, large Internet service providers usually operate multiple geographically distributed IDCs. The enormous power consumption of these data centers may lead to both huge electricity bills and considerable carbon emissions. To mitigate these problems, on-site renewable energy plants are emerging in recent years. Since the renewable energy is intermittent, greening geographical load balancing (GGLB for short) has been proposed to reduce both the electricity bills and carbon emissions by following the renewables. However, GGLB is not able to well deal with the wildly fluctuating wind power when applied into IDCs with on-site wind energy plants. It may either fail to minimize the total electricity bills or incur the costly frequent on–off switching of servers. In order to minimize the total electricity bills of geographically distributed IDCs with on-site wind energy plants, we formulate the total electricity bills minimization problem and propose a novel two-time-scale load balancing framework TLB to solve it. First, TLB models the runtime cooling efficiency for each IDC. Then it predicts the future fine-grained (e.g., 10-min) on-site wind power output at the beginning of each scheduling period (e.g., an hour). After that, TLB transforms the primal optimization problem into a typical mixed-integer linear programming problem and solves it to finally obtain the optimal scheduling policy including the open server number as well as the request routing policy. It is worth noting that the open server number of each IDC will remain the same during each scheduling period. As an application instance of TLB, we also design a two-time-scale load balancing algorithm TLB-ARMA for our experimental scenario. Evaluation results based on real-life traces show that TLB-ARMA is able to reduce the total electricity bills by as much as 12.58 % compared with the hourly executed GGLB without incurring the costly repeated on–off switching of servers.