当前网络政治参与中存在的问题与对策

针对我国当前网络政治参与中存在着非法参与行为多、政务信息不公开致使公众政治参与缺乏信息基础、政府对公众网络政治参与的行为与观点缺乏回应等问题,本文提出了采取完善政治参与和网络政治参与的法治化机制,建立健全网络参政相关法规,保障公民网络参政议政权益,规范和打击非法政治参与行为;修改政府信息公开的法律法规,加大政府信息公开力度与规范网络监督机制;建立政府对公民网络政治参与的回应制度,以解决公民网络政治参与的相关问题,推动法治文明.     

Effect of surface coating on the screw loosening of dental abutment screws

Regardless of the type of performed restoration, in most cases, a screw connection is employed between the abutment and implant. For this reason, implant screw loosening has remained a problem in restorative practices. The purpose of this study was to compare the surface of coated/plated screws with titanium and gold alloy screws and to evaluate the physical properties of coated/plated material after scratch tests via FE-SEM (field emission scanning electron microscopy) investigation. GoldTite, titanium screws provided by 3i (Implant Innovation, USA) and TorqTite, titanium screws by Steri-Oss (Nobel Biocare, USA) and gold screws and titanium screws by AVANA (Osstem Implant, Korea) were selected for this study. The surface, crest, and root of the abutment screws were observed by FE-SEM. A micro-diamond needle was also prepared for the scratch test. Each abutment screw was fixed, and a scratch on the surface of the head region was made at constant load and thereafter the fine trace was observed with FE-SEM. The surface of GoldTite was smoother than that of other screws and it also had abundant ductility and malleability compared with titanium and gold screws. The scratch tests also revealed that teflon particles were exfoliated easily in the screw coated with teflon. The titanium screw had rough surface and low ductility. The clinical use of gold-plated screws is recommended as a means of preventing screw loosening.     

研究合金定向凝固组织的脉冲磁场设备的研制

介绍了脉冲电磁场发生设备的工作原理 ,设计等。并介绍了其如何与合金的定向凝固设备结合 ,以实现对合金的定向凝固组织在脉冲电磁场作用下的研究。     

Atomic force microscopy study of biaxially oriented polypropylene films

Atomic force microscopy (AFM) uses a very sharp pointed mechanical probe to collect real-space morphological information of solid surfaces. AFM was used in this study to image the surface morphology of a biaxially oriented polypropylene film. The polymer film is characterized by a nanometer-scale, fiberlike network structure, which reflects the drawing process used during the fabrication of the film. AFM was used to study polymer-surface treatment to improve wettability by exposing the polymer to ozone with or without ultraviolet (UV) irradiation. Surface-morphology changes observed by AFM are the result of the surface oxidation induced by the treatment. Due to the topographic features of the polymer film, the fiberlike structure has been used to check the performance of the AFM tip. An AFM image is a mixture of the surface morphology and the shape of the AFM tip. Therefore, it is important to check the performance of a tip to ensure that the AFM image collected reflects the true surface features of the sample, rather than contamination on the AFM tip.     

数据中心网络TCP Incast仿真分析

为分析云计算数据中心网络中的TCP Incast问题的产生原因并探讨缓解该问题的有效途径,采用基于NS2仿真实验的方法,通过改变TCP协议类型、交换机缓冲区大小、服务请求单元大小及重传超时RTO值等影响因素,分析传输吞吐率性能的变化。分析结果表明,通过改变这些影响因素有助于缓解TCP Incast问题,但同时也存在各种缺点和局限性。     

国外武器装备电磁环境适应性试验与评价技术及能力发展综述

武器装备的电磁环境适应性已成为制约武器装备能打仗、打胜仗的一个重大问题;西方军事强国非常重视面向复杂电磁环境的武器装备试验与评价技术研究和能力建设,通过相关投资计划的长期持续投入,支持突破其中的关键技术、方法,以及构建相应的试验与评价设施能力;文章从标准规范和研制程序、技术方法、试验设施、科研和能力建设投资计划等几方面综述了国外武器装备复杂电磁环境适应性试验与评价技术和能力发展情况,并在此基础上,提出了对我国武器装备电磁环境适应性试验与评价能力的发展建议.     

开关电源加速贮存寿命方法研究

开关电源具有体积小、重量轻、效率高等诸多优点,凭借其自身的诸多优势,开关电源已经广泛应用于航空航天、通信、以及电子类。由于应用领域的广泛性,开关电源的可靠性引起了人们的重视。论文以阿伦尼斯(Arrhenius)模型为基础,设计了一整套针对开关电源的可靠性评价和寿命预计的试验方案。该方案对试验器件施加温度应力,加速器件的失效过程,并通过一定的加速模型和统计分析方法,外推出正常工作条件下产品的寿命特征。     

Efficient digital certificate verification in wireless public key infrastructure using enhanced certificate revocation list

ABSTRACT

Public key cryptography is widely used for secure data transfer in various applications. The Public key infrastructure provides a foundation that supports public key cryptography, and it is required to deliver the public keys to existing systems or users securely. The public key is exchanged digitally in the form of digital certificates having a certain period of validity. Circumstances may arise under which the validity of the certificates should be ceased, and they need to be revoked. The fast growth of e-commerce demands verification and data transfers to be done in minimum time to maintain high efficiency of communication. In this paper, a new method of developing certificate revocation lists is proposed. The formal model of enhanced PKI for mobile commerce security is put forward. The performance of NTRU is compared with the RSA algorithm and the ElGamal algorithm. The paper also sets forth a comparative analysis of the proposed method with other existing techniques. The results show that the proposed technology has the upper hand over the current methods.     

Virtual life: self and identity redefined in the new media age

In this article, the author discusses her virtual reality installation The Parallel Dimension and goes on to explore the conflicts of identity experienced when a person is confronted with VR as a total immersion. She suggests that the various questions arising through this experience may lead us to a more ambivalent concept of the self.     

核电站数字化反应堆保护系统停堆响应时间分析

为了评价出核电站数字化反应堆保护系统停堆响应的最大时间,根据数字化反应堆保护系统结构,分析出保护系统的响应过程须经过AI输入、IO总线通讯、CPU运算、网络通讯、DO输出处理。并基于DCS定周期扫描的运行方式,得出了各处理过程所需最大响应时间的计算方法,DCS停堆响应时间的评价值就是各部分最大响应时间的累加。最后提出了可缩短响应时间的改进方法。