金属垫片泄漏模型理论研究

依据分形几何理论,结合不可压缩粘性流体层流流动理论,建立基于分形参数的金属垫片泄漏模型,该模型揭示了泄漏率与密封表面形貌之间的关系。研究表明,密封表面分形维数D越大,螺栓-法兰-金属垫片密封系统越不易发生泄漏,这对于法兰和金属垫片密封表面的加工具有重要指导意义。     

基于UDP与FTP协议的远程振动监测与故障诊断系统网络通信方法

随着计算机网络技术的发展,设备振动在线监测与故障诊断系统正朝着分布式网络化方向发展.在远程振动监测与故障诊断系统中,需要解决的一个关键问题就是大批量实时采集数据的传输.本文根据远程振动监测与故障诊断系统对网络通信的需要,建立了一种基于UDP与FTP协议相结合的网络数据传输方法,有效解决了大批量振动相关数据的可靠传输问题.实际应用表明,该方法具有实时性好、可靠性高等优点.     

正弦波交交变频调速系统的研究

交流变频调速是各种调速方法中最有前途的调速方法。在我国,交交变频调速还处于研制阶段,进入实际应用的还比较少.本文研究了用微机作为系统控制器的正弦波交交变频调速系统,精确设计了系统控制电路和控制软件.     

SINOPEC Invests for Overseas Expension

Sinope buys out Lukoil from Kazakh Venture
China further strengthened its position in oil-rich Kazakhstan with its state firm Sinopec paying US$1.2 billion to buy out Russia＇s No.2 oil producer Lukoil from a venture there. Sinopec, Asia＇s largest oil refiner, will become the sole owner of Caspian Investment Resources Ltd, after the deal is completed before the end of 2014.     

Study on effects of pre-treatment and surface roughness on tensile-shear strength of 2060 Al–Li alloy adhesive joints

The forces between adhesive and adherend mainly influenced by the pre-treatment technology of the substrates have important effects on the bonding strength. In this paper, the influence of different pre-treatment processes and surface roughness on the tensile-shear strength of 2060 Al–Li alloy adhesive joints as well as related mechanism was investigated. In this perspective, substrates were processed by mechanical abrasion at different levels and by phosphoric acid anodizing, which resulted in different surface topographies that were characterized by means of roughness measurements. Single-lap joints were prepared using a two-component epoxy adhesive. The tensile-shear strength of joints was measured via destructive testing and the failure modes were analyzed to evaluate the quality of bonding. Results showed that with the increase of surface roughness of Al–Li alloy, the tensile-shear strength of the adhesive joints increased and the failure modes changed from interfacial failure to cohesive failure. The groove structures formed during mechanical abrading were regarded as being responsible for this strengthening behavior. Moreover, a rough porous membrane was produced on adherents’ surface by phosphoric acid anodizing, causing a consolidation of adhesion at the adhesive-substrate interface.     

Crystal growth and characterization of Ho-doped Lu3Ga5O12 for 2 μm laser

Ho:LuGG single crystal was successfully grown by the Czochralski growth method, and its lattice parameter was found to be 12.2371 Å. Its thermal conductivity was measured to be 5.29 W mK⁻¹ at 300 K. Meanwhile, transmission spectra were recorded at room temperature, and then its absorption spectra were obtained combining with the transmission spectra of LuGG crystal. The transition intensity parameters Ω_t (t = 2, 4, 6), the oscillator strengths, fluorescence branching ratios, transition probabilities and the lifetimes of Ho³⁺ in LuGG crystal were all evaluated by the Judd–Ofelt theory. Furthermore, its emission spectra were also determined and analyzed.     

Impact of coarse-grained measurement with finite range on continuous-variable quantum key distribution

In continuous-variable quantum key distribution, detectors are necessarily coarse grained and of finite range. We analyze the impact of both features and demonstrate that while coarse graining adds a fixed error to the estimated excess noise, finite range degrades the estimation accuracy of both transmission and excess noise. Moreover, the inaccurate estimation due to finite range may results in secret key rate underestimation, even misjudgment of security. To compensate these consequences, tuning the modulation variance is a possible way.     

ZTE Communications Call for Papers Special Issue on Using Artificial Intelligence in Internet of Things

Internet of Things has received much attention over the past de-cade.With the rapid increase in the use of smart devices,we arenow able to collect big data on a daily basis.The data we are gather-ing and related problems are becoming more complex and uncer-tain.Researchers have therefore turned to AI as an efficient way ofdealing with the problems created by big data.This special issue of ZTE