A prototype MRPC beam test for the BESⅢ ETOF upgrade

A prototype multi-gap resistive plate chamber (MRPC) with a 2×6 gap structure is developed for the upgrading of the endcap time-of-flight (ETOF) detector in the Beijing Spectrometer (BESⅢ). The prototype MRPC is tested in the E3 beam line of the Beijing Electron Positron Collider (BEPC) with secondary charged particles (π and p, etc) of 600 MeV/c. The test results show that the time resolution of the MRPC can reach 50 ps and that the detection efficiency is greater than 98%.     

智能车载终端数据处理的优化设计

通过分析传统的GPS和车辆航位推算导航系统定位方法的不足,提出使用GPS/DR组合导航技术来获取定位数据,并使用一种新的数据融合方法优化定位数据,通过CDMA 1X无线数据网络改善传输方式.经过实验验证,此优化方案为车辆的实时监控提供了稳定可靠的实时数据传输,提高了ITS系统的性能.     

电子商务专业改革探析

本文在研究电子商务内涵歧义和认识误区的基础上,分析电子商务应用职业岗位和人才培养方面存在的误区,拟在提出电子商务专业核心竞争能力的基础上,进一步分析电子商务专业人才培养问题和专业发展思路.     

基于红外线的音频信号通信装置

由于信息技术的巨大发展,红外通信协议得到了广泛的利用,该设计是利用红外线进行数据传送音频放大信号的一种光电通信装置系统,是通过发射部件、接收部件及中继转发装置结合而成。     

A GEANT4 simulation study of BESⅢ endcap TOF upgrade

A GEANT4-based Monte-Carlo (MC) model is developed to study the performance of endcap time-of-flight (ETOF) at BESⅢ. It's found that the multiple scattering effects, mainly from the materials at the MDC endcap, can cause multi-hit on the ETOF's readout cell and significantly influence the timing property of ETOF. A multi-gap resistive plate chamber (MRPC) with a smaller readout cell structure is more suitable for the ETOF detector due to significantly reduced multi-hit rate (per channel), from 71.5% for currently-used scintillator-based ETOF to 21.8% or 16.7% for MRPC-based ETOF, depending on the readout pad size used. The timing performance of an MRPC ETOF is also improved. These simulation results suggest and guide an ETOF upgrade effort at BESⅢ.     

HFC网络覆盖现状及成本优化模型分析

广电城域网是典型的以机房为核心的广播式网络,机房的地理位置选择与当地地形、人口密度、网络覆盖半径、机房容量、业务配置等密切相关。本文从理论上建立机房建设成本模型,得出最优覆盖半径,并选择有代表性的机房进行现状分析。     

Photoproduction of J/ψ in non-single-diffractive p+p collisions

Significant enhancements of J/ψ production at very low transverse momenta were recently observed by the ALICE and STAR collaborations in peripheral hadronic A+A collisions. The anomalous excess points to coherent photon-nucleus interactions in violent hadronic heavy-ion collisions, which were conventionally studied only in ultra-peripheral collisions. Assuming that the coherent photoproduction is the underlying mechanism responsible for the excess observed in peripheral A+A collisions, its contribution in p+p collisions with nuclear overlap, i.e. nonsingle-diffractive collisions, is of particular interest. In this paper, we perform a calculation of exclusive J/ψ photoproduction in non-single-diffractive p+p collisions at the RHIC and LHC energies based on the pQCD motivated parametrization using the world-wide experimental data, which could be further employed to improve the precision of the phenomenological calculations for photoproduction in A+A collisions. The differential rapidity and transverse momentum distributions of J/ψ from photoproduction are presented. In comparison with the J/ψ production from hadronic interactions, we find that the contribution of photoproduction is negligible.     

基于异常反射型超表面的天线反射面设计

在实际应用中有许多场合需要对电磁波的传播进行人工调控, 传统的光学器件或者人工电磁介质都是采用三维结构, 但传统的三维结构介质很难与其他器件或设备进行集成.利用相位非连续人工电磁表面则可以在传播路径的介质分界面上引入相位突变, 进而实现人工调控电磁波.文章在此基础上在微波波段利用构造分界面相位梯度提出了一种异常反射型超表面的设计, 用作天线反射面可将圆极化波高效地转化为交叉极化波, 为微波段的电磁波人工调控提供了新的手段.根据广义反射定律及斜入射时相位突变修正设计的天线反射面, 在X波段可以实现对入射电磁波的人工调控, 并通过仿真分析验证了该设计方法的准确性, 为人工电磁表面作为天线反射面提供了一种设计思路.