Decode‐and‐forward with full‐duplex relaying

This paper addresses the full‐duplex relaying. Some expressions for outage and average capacity of a two‐hop cooperative system with a full‐duplex relay are derived under an independent but not identically distributed Rayleigh fading environment. Using these expressions, we provide the performance analysis without Monte Carlo simulations. The impact of interference between the relay output and input is investigated. Copyright © 2011 John Wiley & Sons, Ltd.     

VoIP电话的安全问题及防护措施

VoIP电话是综合了传统电信技术与计算机网络技术的一种新型应用。VoIP电话在传输时将信号压缩后封装成IP包，在IP网络上传输，这种传输方式存在着各种安全隐患。讨论了VoIP电话多种可能存在的安全问题，并就这些安全问题作了详细的分析，同时提出了防护措施，以最大限度地保障VoIP电话的安全。     

基于可穿戴传感器数据的人体行为识别数据特征提取方法

随着可穿戴设备的发展与普及,基于可穿戴传感数据进行人体行为检测展现了巨大的研究价值.目前大多人类行为识别工作都是基于视频图像展开的,然而,使用计算机视觉技术进行人类行为识别存在2个挑战:一是很难使参与数据采集的人员在自然状态下采集真实状态下的运动数据,在开展数据采集之前往往需要对参与数据采集的人员进行培训并严格规范其采...     

Electrolyte/Structure?Dependent Cocktail Mediation Enabling High?Rate/Low?Plateau Metal Sulfide Anodes for Sodium Storage

As promising anodes for sodium-ion batteries, metal sulfides ubiquitously suffer from low-rate and high-plateau issues, greatly hindering their application in f...     

Synthesis and characterization of La2Ti2O7 employed for photocatalytic degradation of reactive red 22 dyestuff in aqueous solution

Perovskite structured La₂Ti₂O₇ catalyst prepared by polymerized complex method was characterized and examined the photocatalytic activity by decomposing an azo dyestuff, Reactive Red 22, in aqueous solutions under UV irradiation. La₂Ti₂O₇ powders prepared by polymerized complex method exhibit higher surface areas, better homogeneity and are more sensitive to solution than those prepared by solid-state method. The first derivatives of UV–vis DRS patterns confirmed the complete crystallization of La₂Ti₂O₇ sintered at temperatures higher than 900 °C. The effects of sintering temperature of catalyst and solution pH of photocatalytic reaction were studied. The photocatalytic decomposition of Reactive Red 22 per unit surface area was found to be higher for experiments using La₂Ti₂O₇ than using TiO₂. However, the electron–hole recombination was found to be more obvious for La₂Ti₂O₇ than for TiO₂ because the network of metal cations constructed within La₂Ti₂O₇ enhances the mobility of photogenerated electrons and holes.     

Study on Microstructure and Mechanical Properties of Hot Rolled Low Silicon Containing Phosphorus TRIP Steel

The effects of final air cooling temperature on the microstructure and mechanical properties of hot rolled 0.2C-1.9Mn-0.5Si-0.08P TRIP steel were studied by utilizing OM, SEM, TEM and tensile tests. Experimental results showed that in the multiphase microstructure of the investigated steel when the finish rolling temperature was about 820 ℃ and the final air cooling temperature was in the range of 630-700 ℃, the grain size of most of ferrite was finer (about 4 μm) and which had higher dislocation density, t...     

Progress in Thermal Contact Resistance

The developments of aeronautics and astronautics require engines of higher quality. The temperature distribution in combustion engine is highly influenced by the thermal conduct resistance. To predict the temperature field of the hot-end assemblies of combustion engine, the thermal contact resistance must be considered. The object of the study is to propose a model of high application including in conditions of high temperature and high pressure. Up to date, many models and empirical or semi-empirical corre...     

Structural design and mechanical performance test of densely drilled glass fiber reinforced plastics pipelines

Densely drilled glass fiber reinforced plastic (GFRP) pipelines are thought to be of prosperous future in sand control in oilfield. However, due to the fact that the mechanical properties of the perforated GFRP pipelines are always lowered remarkably, some structural design work must be done. Several key factors, including the winding angle of the glass fibers, the mechanical properties of the matrix resin were considered carefully in advance. The tensile strength, compressive strength and the screw-crushing properties of the GFRP pipelines were measured subsequently. Most of the test results were coincided with what had been expected during structural design. The winding angle was proved to be an important factor in improving the mechanical performance of perforated GFRP pipelines. Mechanical property of the matrix resin was another important factor in determining the performance of the GFRP pipelines. The effect of the hole-size and distribution on the mechanical performance of the heavily perforated GFRP pipelines always depended on the winding angle and matrix resin. In the screw-crushing test, the GFRP pipelines showed to be easily destroyed by the slowly rotating drill head.