Giant magnetocurrent in triple-barrier ferromagnetic resonant-tunneling diode with different magnetization configurations

The authors theoretically investigate a triple-barrier ferromagnetic resonant-tunneling diode composing nonmagnetic couple wells and three GaMnN magnetic barriers, in which two kinds of antiparallel configurations are formed by changing the relative orientation of magnetization in the barriers. Based on a two-band model, the achievement of large magnetocurrents in the resonant bias regime is proposed under an optimal magnetization configuration. The magnetocurrents in both antiparallel configurations of triple-barrier system are much higher than that in double-barrier structure.     

Perturbation to Mei Symmetry and Adiabatic Invariants for Nonholonomic Systems in Terms of Quasi-Coordinates

Based on the concept of adiabatic invariant, the perturbation to Meisymmetry and adiabatic invariants for nonholonomic mechanical systems interms of quasi-coordinates are studied. The definition of the perturbationto Mei symmetry for the system is presented, and the criterion of theperturbation to Mei symmetry is given. Meanwhile, the Mei adiabaticinvariants for the perturbed system are obtained.     

A prototype of a high rating MRPC

Six-gap resistive plate chamber (MRPC) prototypes with semiconductive glass electrodes (bulk resistivity～1010.cm) were studied for suitability in time-of-flight (TOF) applications at high rates. These studies were performed using a continuous electron beam of 800 MeV at IHEP and an X-ray machine. Time resolutions of about 100 ps and efficiencies larger than 90% were obtained for flux densities up to 28 kHz/cm2.     

Circulation model for water circulation and purification in a water Cerenkov detector

Owing to its low cost and good transparency, highly purified water is widely used as a medium in large water Cerenkov detector experiments. The water circulation and purification system is usually needed to keep the water in good quality. In this work, a practical circulation model is built to describe the variation of the water resistivity in the circulation process and compared with the data obtained from a prototype experiment. The successful test of the model makes it useful in the future design and optimization of the circulation/purification system.     

N巴黎势和可能的p共振态(英文)

通过求解N巴黎光学势的复薛定谔方程,研究了N系统的近阈束缚和共振行为,得到了一个p系统的13P0共振态.发现其能量和宽度与最近BES用Breit Wigner(B W)公式分析J/ψ→γp衰变的实验数据给出的结果相容.讨论了这一结果的含义及进一步研究的建议.     

激光诱导击穿光谱法定量分析水泥中的铜元素

为定量分析水泥中的铜(Cu)元素,根据激光诱导击穿光谱分析方法(Ll BS)的特点,建立了激光诱导击穿光谱分析系统。采用标准加入法为定标方法,制备了5个不同含铜量的水泥样品。根据LIBS谱图,以213.598 nm和219.958 nm作为分析线。应用Savitzky-Golary卷积平滑方法对光谱数据进行了预处理,比较了Guass、Lorentz和Voigt拟合方法对光谱曲线的拟合效果。对测量结果采用一元线性拟合建立了相应的定标曲线,213.598 nm和219.958 nm定标曲线的校正决定系数分别为0.994 8和0.986 4,平均相对误差分别为3.20%和5.78%。实验结果表明:213.598 nm作为分析线的准确度优于219.958 nm分析线,该方法能够满足水泥中Cu元素定量分析的要求。     

不同驱动力下瓦斯水合物生长过程Raman光谱特征

基于煤矿瓦斯(CH₄∶C₂H₆∶N₂=67.5∶22.5∶10)水合物相平衡曲线开展四种驱动力ΔP水合动力学实验,利用可见显微Raman光谱仪获取水合物生长过程光谱图,根据水合物相中C₂H₆ C-C键伸缩振动特征峰Raman位移确定了4组实验中水合物为sⅡ结构。基于van der Waals与Platteeuw模型获取瓦斯水合物生成过程中水合物相气体组分及水合指数变化规律。研究表明： 驱动力的大小影响水合物的稳定性,随着驱动力的增加,CH₄相比C₂H₆逐渐占据更多的孔穴结构,CH₄在水合物相内比例增加,水合物稳定性越强;瓦斯中N₂,CH₄和C₂H₆进入水合物孔穴优先级可以通过分子与水合物孔穴的直径比进行确定,分析认为在sⅡ水合物结构中小孔穴CH₄优先级最高,大孔穴C₂H₆最高;基于瓦斯水合物稳定性,对水合物生长过程客体分子的物质传递规律进行描述,为瓦斯水合物的微观生长提供理论基础。     

色噪声对光学双稳态的影响

采用统一色噪声近似构建了由乘法色噪声驱动的纯吸收型光学双稳态状态方程,并分析了色噪声对光学双稳态的影响,将结果与白噪声驱动的光学双稳态进行比较.结果表明:当乘法噪声与加法噪声处在正关联时,增加乘法色噪声的自关联时间r,光学双稳性的区域显著变宽,即磁滞回线面积变大;当乘法噪声与加法噪声处在负关联时,只有乘法噪声较小时,改变乘法色噪声的自关联时间r,光学双稳态才发生改变;当乘法噪声的自相关时间等于零时,本文模型退化为乘法白噪声驱动的光学双稳性状态方程.