一种新的直扩超宽带系统快速同步方案

本文提出了一种新的基于能量窗的直扩超宽带系统码片同步方法，通过设计具有重复特性的码来提高能量窗的信噪比，从向可以较为准确地获得码片同步，并将窗口中的信息作为接收端本地信号与接收信号进行匹配接收，这样可以存未知接收信号相位的情况下有效地接收多径能量，提高接收信噪比。在完成码片同步之后再进一步进行PN码的相位同步，这里以线性搜索为例分析得到超宽带信号总的平均同步时间，并与现有的超宽带同步方案进行了比较，新方案将信号捕获分成两部分完成，大大降低了超宽带信号捕获时间。     

Singlet-Triplet Transition in Quantum Dots Confined by Triangular and Bowl-Like Potentials： the Effect of Electric Fields

We theoretically investigate the energy spectra of two-electron two-dimensional （2e 2D） quantum dots （QDs） confined by triangular potentials and bowl-like potentials in a magnetic field by exact diagonalization in the framework of effective mass theory. An in-plane electric field is found to contribute to the singlet-triplet transition of the ground state of the 2e 2D QDs confined by triangular or bowl-like potentials in a perpendicular magnetic field. The stronger the in-plane electric field, the smaller the magnetic field for the total spin of the ground states in the dot systems to change from S = 0 to S = 1. However, the influence of an in-plane electric field on the singlettriplet transition of the ground state of two electrons in a triangular QD modulated by a perpendicular magnetic field is quite small because the triangular potential just deviates from the harmonic potential well slightly. We find that the strength of the perpendicular magnetic field needed for the spin singlet-triplet transition of the ground state of the QD confined by a bowl-like potential is reduced drastically by applying an in-plane electric field.     

Luminescent Properties and Mechanism of Gd1-x-yAlO3Eux,REy

GAP:Eu,Re(Gd1-x-yAlO3Eux,REy?A，RE=Pr or Ce) powders were prepared by a nitrate-citrate process. It is found that luminescent intensity decreases when GAP:Eu is co-doped with Pr or Ce. The phenomena of spectra prove that there is a resonant energy transfer between Eu and Pr, by the absorption and emission of lower-energy phonon, and also Ce sensitizer decreases the activator energy level from host→Eu. The two factors are considered to be the main reasons for decrease of the luminescent intensity for the co-doped GAP:Eu,Re.     

双脉冲电子束源实验

2MeV直线感应加速器注入器系统由电子束产生器和脉冲功率系统组成。电子束产生器包括由感应腔组成的阴极电压叠加器、阳极电压叠加器和真空二极管及束输运系统。脉冲功率系统则包含初级功率源Marx、次级功率源Blumlein线和触发系统，其作用是为感应腔提供一个具有数十纳秒平顶宽度的高压脉冲，激发感应腔在感应腔间隙上获得一个加速电场。在2MeV注入器功率系统中，4个Blumlein线的充气开关是由发散装置的输出触发信号进行导通控制的。通过控制发散输出触发信号到达Blumlein线开关的时间，即可以实现Blumlein线开关在不同时间内触发导通，使Blumlein线依据所设定的时间顺序输出激励脉冲，从而在真空二极管上获得高压脉冲串。由于功率系统采用的是182C结构，即一根Blumlein线驱动两个感应腔，因此最多可以实现四脉冲串列。     

脉冲中子探测系统的中子灵敏度能量响应

为了获得脉冲中子探测系统的中子灵敏度能量响应，编制了适合裂变中子测量探测系统灵敏度能响的一系列专用程序，研究了相应的实验标定技术，采用理论计算和实验验证相结合的方法，对几套探测系统中子灵敏度能量响应进行了研究，初步解决了标定需要的“单能、脉冲、高强度、多个不同能量的中子源”问题，使不确定度大大提高，满足了测量的要求。     

SP3767高性能低功耗电调谐FM接收及处理集成电路

1、产品及其简介SP3767是主要用于MP3、手机等便携式产品的高性能低功耗电调谐FM立体声接收及处理集成电路,采用以双极为主的0.6μmBiCMOS工艺设计,HVQFN40带散热片无引线40管脚的形式封装。电路内部集成了     

Ultraviolet Luminescence in Mg0.12Zn0.88O Alloy Films

We investigate the origin of ultraviolet （UV） emission from Mg0.12 Zn0.88 O alloy thin films with a wurtzite structure fabricated on c-plane Al2O3 substrates by plasma assisted molecular beam epitaxy. At room temperature, the absorption edge and UV emission band of the Mg0.12Zn0.88O film shift to high-energy side compared with ZnO films. Temperature dependence of the photoluminescence spectra shows that the UV emission is composed of free exciton and neutral donor bound exciton emissions. Two-step dissociation processes of the UV emission are observed with the increasing temperature. The thermal quenching mechanism is attributed to the dissociation of the free exciton from the neutral donor bound exciton in the low temperature region and the dissociation of free electron and hole from the free exciton in the high temperature region.     

A Generalization of the Mean Size Formula of Wavelet Packets in Lp

The purpose of this paper is to investigate the mean size formula of wavelet packets in Lp for 0 〈 p ≤ ∞. We generalize a mean size formula of wavelet packets given in terms of the p-norm joint spectral radius and we also give some asymptotic formulas for the Lp-norm or quasi-norm on the subdivision trees. All results will be given in the general setting,     

Dependence of Isospin Fractionation on Beam Energy in Heavy Ion Collisions at Intermediate Energies

We investigated the dependence of isospin fractionation degree (N/Z)n/ (N/Z)Nfrag on the beam energy by using the isospin dependent quantum molecular dynamics model (IQMD). The (N/Z)n and (N/Z)Nfrag are the neutron proton ratio of nucleon emission (gas phase) and that of fragment emission (liquid phase) respectively. The calculated results show that (N/Z)n / (N/Z)Nfrag enhances with increasing the beam energy due to the increase of excitation energy of colliding system. But above properties is only occurred in the definiteenergy region.