A private versus a public space: Anonymity and buying decorative symbolic goods for avatars in a virtual world

The virtual world has become a new channel in which people can contact with others, and organizations can provide service to their customers. Selling symbolic virtual goods has also emerged as a new economy in the virtual world. Such symbolic goods cannot facilitate people to accomplish any specific tasks; people buy them simply to decorate their avatars. This study is based on the theories of symbolic consumption, self-presentation, and computer-mediated environment, to investigate why people buy decorative symbolic goods in the virtual world. The results show that people buy symbolic virtual goods for both emotional and social values. While user perceived social presence and telepresence affect both social and emotional value of symbolic goods, individual self-presentation motivation affects only social value. Besides, anonymous users in the virtual world show behaviors that differ with non-anonymous ones.     

RC框架静力与动力弹塑性分析的比较研究

介绍了静力与动力弹塑性分析的基本原理和分析方法．采用Perform-3D软件对1幢8层钢筋混凝土框架结构分别进行了静力和动力弹塑性分析．通过比较分析结果,对于多层质量刚度分布均匀的框架结构,静力与动力弹塑性分析计算的最大层间位移角基本接近,但静力弹塑性计算结果略偏保守．     

跨孔超高密度电法CT在岩溶勘察中的应用

常用电阻率法的空间效应和视电阻率拟断面记录点对应深度方面的不确定性,以及对场地的要求随深度增加而增加,而分辨率却下降等等制约因素,使其工程应用受到限制,尤其是在解决孔与孔之间的电阻率情况更是一筹莫展。本文所推荐的跨孔超高密度电法是根据电场的基本理论和地震CT勘探的原理,提出了利用在平行钻孔中布设电极、然后利用一孔的两个电极供电、其余的电极同时测量的一种电法测量方式;它不仅比较准确地解决了孔与孔之间的电阻率问题,对场地无太大要求且施工较方便;本文通过对清远伦洲大桥18#、19#桥墩内岩溶发育情况进行电阻率的测试,充分证明该技术在解决此类问题的有效性和准确性。     

大区域电网动态频率空间分布特性分析

频率是电力系统重要的运行参数,也是衡量电能质量的重要指标。系统频率保持额定值是系统有功功率供需平衡和系统正常运行的标志。当发电机组跳闸或大容量负荷投切造成功率不平衡时,频率发生变化继而发生频率动态过程。鉴于频率动态过程研究的重要性,本文对某大区域互联电网频率的动态过程进行了仿真,主要从不同电压等级的频率动态过程差异,同一功率脱落事件在不同位置观测的频率动态过程,相同功率脱落、不同脱落方式在同一点观测三个方面对其频率动态空间分布特性做了仿真研究,为低频减载装置的正确整定和配置提供依据。     

Gaseous and electrochemical hydrogen storage kinetics of as-quenched nanocrystalline and amorphous Mg2Ni-type alloys

The nanocrystalline and amorphous Mg₂Ni-type Mg₂Ni_1?x Co _x (x = 0, 0.1, 0.2, 0.3, 0.4) alloys were synthesized by melt quenching technology. The structures of the as-cast and quenched alloys were characterized by XRD, SEM and HRTEM. The gaseous hydrogen storage kinetics of the alloys was measured using an automatically controlled Sieverts apparatus. The alloy electrodes were charged and discharged with a constant current density in order to investigate the electrochemical hydrogen storage kinetics of the alloys. The results demonstrate that the substitution of Co for Ni results in the formation of secondary phases MgCo₂ and Mg instead of altering the major phase Mg₂Ni. No amorphous phase is detected in the as-quenched Cofree alloy, however, a certain amount of amorphous phase is clearly found in the as-quenched alloys substituted by Co. Furthermore, both the rapid quenching and the Co substitution significantly improve the gaseous and electrochemical hydrogen storage kinetics of the alloys, for which the notable increase of the hydrogen diffusion coefficient (D) along with the limiting current density (I _L ) and the obvious decline of the electrochemical impedance generated by both the Co substitution and the rapid quenching are basically responsible.     

相变材料微胶囊机械性能评价方法研究进展

相变材料微胶囊广泛应用于宇航飞机、新型战机、雷达系统、节能建筑、废热回收、农业大棚、冷热循环流体和调温服装等领域。从使用角度讲,相变材料微胶囊的囊壁应具有良好的机械性能,但不同应用场合对微胶囊囊壁机械性能的要求也不同。综述了国内外关于相变材料微胶囊机械性能评价方法的研究进展。指出应综合分析相变材料微胶囊颗粒在若干典型应用场合下的受力状态,并在此基础上构建具有较宽适用范围的机械性能评价方法。     

330MW燃煤电厂SCR技术的应用研究

研究选择性催化还原法（SCR）在330MW燃煤电厂上的应用,分析了SCR系统工艺流程、工作原理及影响脱硝效率的因素。经过较长时间稳定运行,系统脱硝效率在80%以上,达到设计参数,为燃煤电厂NOx控制提供参考。     

Stabilization of quantized systems based on Kalman filter

This paper is concerned with the design and stability analysis of networked control systems with quantization effect and noisy measurement. Quantization strategy used here is a traditional uniform one, and Kalman filter is applied to obtain the estimated states. Under some assumptions and conditions, a sufficient condition is given for the closed-loop system to be stable based on Lyapunov theory and invariable set theory. Two examples are given to show the effectiveness of the main results.     

多核体系下的并行任务构建

基于多核体系下的系统运行效率越来越受到各行业的关注,一个系统往往是由若干软件子模块构成的.一个完整的系统可以由Tomcat,Httpd以及Lucene这3个软件模块构成.这些软件本身均进行了一定的优化,各自运行效率都良好,可是如果将它们整合成一个系统,其效率的提高仍需要从整体多方面考虑.从不同软件的子任务之间的关系入手,通过分析它们的特点,提出苦干提高整体性能的方案.研究贡献在于以下3个方面:1)线程间同步操作的消除;2)通过多任务重排提高并行度;3)系统调用的单线程化.结果表明系统整体性能得到了提高,同时,每个子任务完成的功能更加清晰明了.     

蛋氨酸生产闪蒸工况角型阀门的研制

介绍了目前国内饲料级蛋氨酸生产项目闪蒸工况使用的角阀的现状,重点介绍了研制过程中如何针对实际应用过程中出现的问题进行的改进设计,结合自身切实经验,分别从阀门结构设计、内件材料选择、密封件材质选择和角阀零件的机加工工艺等方面,论述了闪蒸工况下角型阀门的特点以及加工过程中能够提高加工精度所需注意的问题,这些特点以及加工注意事项能够较好的保证该类型角阀能够适应饲料级蛋氨酸生产中的闪蒸工况要求。