Effect of Background Noise on the Photon Statistics of Triggered Single Molecules

We theoretically derive exact expressions for Mandel‘s Q parameter of the triggered single molecular source, which is inferred from the probabilities PRs (n) using the recorded of each photon detection event based on Hanbury Brown and Twiss detection. The real triggered source is recognized as an ideal single photon source with a Poissonian statistics background. How to decease the background and to increase the efficiency are discussed. It is established that the sub-Poissonian statistics formation can be determined by comparing the measured QRs of the real single triggered molecular with Qc of the Poissonian source containing the same mean photons. By this method, we also give an efficient way to measure signal-to-background ratios of triggered single photons.     

一种基于深度学习的驾驶员打电话行为检测方法

针对现有驾驶员打电话行为检测方法存在精度低、实时性能差以及免提通话无法检测等问题,提出一种基于深度学习的多特征融合检测方法.该方法通过融合手持电话行为与讲话行为检测结果,实现对驾驶员打电话行为的检测.基于构建的浅层卷积神经网络,包含5层特征提取网络以及2层全连接层,可实现对听筒及免提接听两种手持电话行为的检测;同时,通过级联形状回归算法得到嘴部18个特征点及其宽高比,并根据连续20帧图像的嘴巴宽高比振荡差值来检测讲话行为.实验结果表明,该方法在实际驾驶场景下的平均检测准确率达到95.6％,平均检测耗时低至230 ms/frame,综合检测性能得到明显改善.     

强大图像处理专家 精巧彩色激光打印机

综观目前的彩色激光打印机市场，面向中小型工作组的彩色解决方案可谓层出不穷。但真正能够满足不基于Windows系统的开发软件，Mac、DTP用户的小型办公解决方案却并不多见。柯尼卡美能达magicolor 2550就是个例外。作为一款小巧强大的小型网络彩色打印机，magicolor 2550强大的图像处理和网络输出能力，值得专业用户期待。     

TD-SCDMA直放站ALC控制方案的研究

文章首先论述了传统的ALC控制思想,根据TD-SCDMA制式特殊的信号格式分析了现有ALC方案在控制TD-SCDMA这种突发信号时的局限性,提出了一种基于软件实现的分时隙ALC控制方案.     

电容参数对超导储能重复频率脉冲电源性能影响

介绍了单级超导电感储能重复频率脉冲电源电路,对放电过程及转换电路中电容器的作用进行了分析,建立了单级脉冲电源的基础试验平台和电路仿真模型,利用仿真分析了不同电容参数对脉冲电源性能的影响。仿真波形与实际试验波形具有较好的一致性,能够很好地反映超导电感储能重复频率脉冲电源的输出性能,证明了电路仿真模型是可行的。仿真结果表明:电容参数对电容电压和最大电容储能比例影响较大,对输出脉冲峰值和负载的实际能量利用效率影响相对较小,选择较大的电容参数,可以降低电容电压,从而降低脉冲电源对断路开关的耐压要求,但是同样会降低输出脉冲峰值和增大最大电容储能比例。在未来大功率系统中,应在满足断路开关耐压的条件下,选择较小的电容参数。     

76Ge的2νββ衰变寿命和矩阵元

利用76Ge的壳模型波函数计算76Ge的2νββ衰变矩阵元和寿命.结果可以与最近观察到的76Ge的2νββ衰变寿命相比拟.进而从最近的0νββ衰变的实验寿命可以算出有效中微子质量上限是0.4eV.     

Status of CSNS H- ion source

A new H^- ion source has been installed successfully and will be used to serve the China Spallation Neutron Source (CSNS). In this paper, we report various components of the ion source, including the discharge chamber, temperature, cooling system, extraction electrodes, analyzing magnet, remote control system and so on. Compared to the previous experimental ion source, some improvements have been made to make the ion source more compact and convenient. In the present arrangement, the Penning field is generated by a pair of pole tip extensions on the 90° analyzing magnet instead of by a separate circuit. For the remote control system, F3RP61-2L is applied to the accelerator online control system for the first time. In the running of the ion source, a stable pulse H^- beam with a current of 50 mA at an energy of 50 keV is produced. The extraction frequency and pulse width is 25 Hz and 500 μs, respectively. Furthermore, an emittance scanner has been installed and measurements are in progress.     

功率放大器数字预失真技术的研究

在宽带码分多址(WCDMA)等宽带通信系统中,射频功率放大器呈现出严重的电记忆效应和热记忆效应,产生频谱再生和邻道干扰,传统的无记忆预失真技术已经无法消除信号失真而达到理想的线性化效果.针对此类有记忆性的功放,文章提出一种新的记忆多项式预失真器,以跟踪射频功率放大器特性的变化, 并进行非线性补偿.     

关于移动电子商务数据安全的探讨

移动电子商务带来前所未有的机遇,但其数据安全问题仍然是运营商、企业和用户最关心和担心的问题。本文从WAP的安全体系入手,探讨移动电子商务中数据安全传输的实现方式。