Implementing two optimal economical quantum cloning with superconducting quantum interference devices in a cavity

We propose a unified scheme to implement the optimal 1→ 3economical phase-covariant quantum cloning and optimal 1→3 economical real state cloning with superconducting quantum interference devices (SQUIDs) in a cavity.During this process,no transfer of quantum information between the SQUIDs and cavity is required.The cavity field is only virtually excited.The scheme is insensitive to cavity decay.Therefore,the scheme can be experimentally realized in the range of current cavity QED techniques.     

Orbit determination and time synchronization for a GEO/IGSO satellite navigation constellation with regional tracking network

Aiming at regional services,the space segment of COMPASS (Phase I) satellite navigation system is a constellation of Geostationary Earth Orbit (GEO),Inclined Geostationary Earth Orbit (IGSO) and Medium Earth Orbit (MEO) satellites.Precise orbit determination (POD) for the satellites is limited by the geographic distribution of regional tracking stations.Independent time synchronization (TS) system is developed to supplement the regional tracking network,and satellite clock errors and orbit data may be obtai...     

Measurements on diproton emission from the break-up channels of ~(23)Al and ~(22)Mg

Two-proton relative momentum distributions from the break-up channels 23Al→p+p+21Na and 22Mg→p+p+20Ne at an energy of 60-70 A MeV have been measured together with two-proton opening angles at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The results demonstrate the existence of diproton emission component from single-step 2He for highly excited 23Al and 22Mg.     

条形码技术在方志馆典藏工作中的应用

条形码技术是一种应用广泛的光电数据输入技术,具有编码、数据识别、数据采集、条码印刷等多项功能。本文简述了条形码技术的原理及其在方志馆编录、典藏、流通环节中的作用。论述了二维码技术的应用对方志馆在馆藏资料自动化管理和方志馆数字化建设方面产生的革命性影响。     

双金属掺杂M2@Si20(M=Ti, Zr, Hf)团簇结构和性质的理论研究

采用密度泛函理论(DFT)和相对论有效原子核势近似(RECP),对M2@Si20(M=Ti,Zr,Hf)团簇的几何结构和电子结构性质进行研究,发现内嵌的金属二聚体和十二面体硅笼构成了稳定的富勒烯结构。通过对团簇电子结构的分析,结果表明Si20团簇掺杂双金属后稳定性得到了提高。对团簇的电荷布局分析表明过渡金属原子(Ti, Zr, Hf)和硅笼之间发生了电荷反转。     

Eigenspace-based source number estimation for direction-of-arrival estimation

A eigenspace-based source number estimation was presented.It projects the estimated covariance matrix of array signal into signal eigen-subspace and noise eigen-subspace, respectively.Using the orthogonality between signal eigen-subspace and noise eigen-subspace, it is easy to differentiate the contribution of signal and noise by using the criterion value,or the magnitude of projection.Like the Direction-of-Arrival(DOA) estimation algorithm,the estimator uses the eigenvalue decomposition of covariance matrix with order M×M,where M is the number of elements,and hence can save much computational burden.To reduce more computational burden,the estimation can be implemented by the decomposition in the real-value space.Computer simulation demonstrates the distribution of criterion value and the performance of the estimation method.The estimation method was also tested with the sonar data,which shows good performances.     

车辆天窗气动噪声的数值分析与实验研究

本文从汽车天窗气动噪声的机理入手,利用与实车几何尺寸为1:5的简化模型进行了空腔绕流的数值计算,分析了其流场结构及气动噪声产生的原因.在低速静音风洞中进行了不同流速下的流场和声场实验研究,研究了天窗不同位置的速度剪切层变化,以及不同流速下的声压级变化,发现了除了特征频率下的风振噪声,还存在较大频率范围的气动噪声,其随着...     

端部周期加热下管内气温奇异分布的实验研究

设计搭建了端部周期加热时管内气体热声对流的实验平台,对端部周期加热引起的气体热声对流作用下管内气体的温度分布进行了实验研究。该实验以氩气为工质,利用三极管控制加热电路实现周期性加热;测量了不同加热频率下管内的气体温度,并与常热流加热时的温度分布进行对比,结果表明端部周期加热时管内气体的温度分布与同功率下常热流加热时存在明显的差异,并且在某些测点出现了温度的奇异分布。本实验验证了超温现象的存在,为管内气体热声对流现象的进一步研究奠定了基础。     

高效同轴脉冲管制冷机性能的实验研究

同轴式脉冲管制冷机具有结构紧凑、与器件耦合简单的优点,在实际应用中得到了越来越广泛的采用.本文对一台经理论优化设计的高频同轴脉冲管制冷机进行了实验研究,采用自制的直线压缩机驱动,惯性管/气库作为调相机构,在输入电功150 W、冷端温度为77 K时得到了9.86 W的制冷量,相对卡诺效率达到18.4%,这是目前同轴脉冲管...