Energy confinement time and heat transport in initial neutral beam heated plasmas on the large helical device

The confinement characteristics of large net-current-free plasmas heated by neutral-beam injection have been investigated in the Large Helical Device (LHD). A systematic enhancement in energy-confinement times from the scaling derived from the medium-sized heliotron/torsatron experiments have been observed, which is attributed to the edge pedestal. The core confinement is scaled with the Bohm term divided by the square root of the gyro radii. The comparative analysis using a dimensionally similar discharge in the Compact Helical System indicates gyro-Bohm dependence in the core and transport improvement in the edge region of LHD plasmas.     

Excitation of toroidicity-induced Alfvén eigenmodes by the electrodes inserted in a heliotron/torsatron plasma

A novel method of exciting shear Alfvén waves using electrodes inserted in a plasma was developed for basic study of Alfvén eigenmodes in a heliotron/torsatron plasma. The electrodes can induce excitation current along the confinement field line, and generate magnetic perturbations perpendicular to the confinement field. By sweeping the frequency of the current in a cold plasma, the toroidicity-induced Alfvén eigenmode was resonantly excited at the predicted frequency and radial location. Plasma response to the applied magnetic perturbations indicates a fairly large damping rate caused by continuum damping.     

高能多粒子产生反常标度性研究中的相空间变量选择

讨论高能多粒子产生反常标度性研究中的各种相空间变量选择.为了克服几种常用的横向相空间变量的缺点,引入了一组新的横向变量.这组变量在讨论高能多粒子产生中的反常标度性时有优越性.给出了这组新变量的统计分布及数值特征,讨论了它们之间的独立性,给出了相应的累积变量.     

光纤探针传输效率的研究

用实验方法测量了光纤探针的传输效率随光纤圆锥角的变化关系,给出了传输效率曲线。通过测定探针传输效率的实验可以看到,只要光纤探针的锥角在30°~55°范围内,就具有高透过率、高分辨率纳米微探针。测量了传输效率与光波波长的关系。     

The high-voltage electron microscope

The advantages of using very high voltages for electron microscopy are reviewed, in respect of greater specimen thickness and reduced chromatic aberration. For polymers and possibly with living material, the lower radiation damage in a given thickness is also valuable. The special problems in the design and construction of microscopes operating up to 1 Mv are discussed. We are still in a stage of rapid development, and some possibilities for the future are outlined. The main areas of application of high voltage microscopes are beginning to be defined; some examples are given of what has been done with the Toulouse and Cambridge microscopes to date.     

Selected formulas for the magnetic susceptibility of systems with 4f-ions

Basic formula for the magnetic susceptibility of systems with 4f-ions within the LS-coupling scheme is introduced. The high temperature behaviour of thermodynamic average values is considered and the result is used for a high temperature expansion of the magnetic susceptibility. The results in the whole temperature range are given for systems described by one-particle Hamiltonians and effective one-particle Hamiltonians are considered. Explicit formulas are given for the case of a crystal field Hamiltonian and Heisenberg interaction Hamiltonian including molecular field approximation.     

用于二维光址多分址系统的代数同余码研究

总结了线性、二次和双曲等有限域内的代数同余运算在光码分多址系统中的应用,将代数同余码分为三类：跳频码、扩时码和跳频扩时码,并给出它们的构造公式。提出了一种同时采用这三类编码分别用以提供不同类型用户服务的二维光码分多址方案,该系统方案尤其适合于大量用户需要常规服务,而少部分用户需要高速或高服务质量(QoS)服务的情况,具有对速率和服务质量的强适应能力。为了证明该系统方案的可行性,首先证明了三种码字的互相关常数,然后推导了达到各种互相关值的概率,最后得出混合系统中不同类型干扰对系统误码率的影响,并进行了数值分析与讨论。     

Oriented growth and definition of medium angle semiconductor bicrystals

The physical and metallurgical procedure in the preparation of semiconductor bicrystals is described, methods of seed orientation are given and precision limits are discussed. It is shown that medium angle boundaries can be grown at a high precision if proper techniques are used. A number microphotographs of grown grain boundary structures is given.     

闪光照相中FXRMC和MCNP4B的散射比较研究

 散射问题是高能辐射成像研究中的一个重要问题,采用蒙特卡罗模拟来确定散射对提取客体信息的影响是一种重要的研究手段。简单介绍了FXRMC和MCNP4B程序的特点及其记录方式;在确保相同输入参数的条件下,针对不同的照相模型进行了对比计算。结果表明两个程序计算的散射照射量相对差别小于5%,说明这两个程序具有较高的符合程度。通过与实验结果的比较发现,这两个程序模拟的散射分布与实验结果基本一致,均可用于高能闪光照相的模拟研究。还给出了在散射检验方面的一些建议。     

TeSeIn相变记录薄膜的微观特性研究

TeSeIn是一种可逆光存贮介质.分别用单源热蒸发和磁控溅射制备TeSeIn膜.利用透射电镜(TEM)研究了膜的结构和微观形貌.利用俄歇剖面技术(AES-PRO)给出了膜的组分深度剖面,分析了TeSeIn记录介质膜与ZnS保护膜界面间的互扩散大小.利用X光电子能谱(XPS)分析了组元深能级结合能的化学位移.最后根据上面实验结果简要讨论了制备稳定的多元记录介质膜的方法.     

Analysis of nonlinear beam-wave interaction of gyro-peniotron at harmonics

An analysis of the nonlinear beam-wave interaction of the gyro-peniotron at high harmonic is presented in this paper. It bases on a ballistic large-signal theory of the gyropeniotron assuming a given RF field distribution in the resonator. The proposed method is applicable to arbitrary harmonic numbers and to arbitrary TE modes. Analytical results of its operational characteristics are given using computer simulations. E. g. an efficiency of 45% for the third harmonic has been calculated. The results show that the gyro-peniotron could be potentially a high efficiency, high power millimeter-wave device at a low magnetic field.     

Advanced turboprop noise prediction based on recent theoretical results

This paper is about the development of a high speed propeller noise prediction code at Langley Research Center. The code utilizes two recent acoustic formulations in the time domain for subsonic and supersonic sources. The selection of appropriate formulation is automatic in the code. The structure and capabilities of the code are discussed. Grid size study for accuracy and speed of execution on a computer is also presented. The code is tested against an earlier Langley code. Considerable increase in accuracy and speed of execution are observed. Some examples of noise prediction of a high speed propeller for which acoustic test data are available are given. A brisk derivation of formulations used is given in Appendix 1.     

图像采集系统特性参数的测试与评价

本文介绍了一种用于测量的高性能、高精度图像采集与处理系统的基本构成，以及为保证测量精度而对ＣＣＤ摄像机进行的改造。讨论了图像采集系统的主要时域特性参数，包括平均暗输出、暗输出不均匀性、暗噪声、动态范围、光电响应不均匀性、光电响应线性度、信噪比等。阐述了以上特性参数的定义和测试评价方法。给出了被测系统的特性参数。同时给出了噪声分布直方图和线性响应曲线。     

Compact Finite Difference Scheme for the Fourth-Order Fractional Subdiffusion System

In this paper, we study a high-order compact difference scheme for the fourth-order fractional subdiffusion system. We consider the situation in which the unknown function and its first-order derivative are given at the boundary. The scheme is shown to have high order convergence. Numerical examples are given to verify the theoretical results.     

闪光辐射照相及光学高速摄影图象的增强处理

本文介绍图象增强处理技术在闪光辐射照相图象及光学高速摄影图象中的应用.针对闪光图象及高速摄影图象的特点,研究了一些有效的图象增强方法,取得了很好的应用效果. 文中给出了部分应用实例.     

Quantum Electrodynamics at High Temperature: (I). One Spatial Dimension

The photon sector of Quantum Electrodynamics (QED) in one spatial dimension is analyzed at high temperature to all orders of perturbation theory. The imaginary-time formalism is used. The photon self-energy and propagator at finite temperature with vanishing frequency are given to second order of perturbation theory. Based upon them, an improved perturbation theory which incorporates Debye screening if formulated. In the infinite-temperature limit, the photon sector becomes equivalent to a massive scalar boson field plus a masslees pure gauge field and both are decoupled: all connected Green's functions with given external momenta much smaller than the temperature and containing, at least, one closed fermion loop with four or more vertices vanish. An approximate generating functional yielding all leading high-temperature corrections to all connected Green's functions is preaented. The Iast result leads to establish for one spatial dimension a conjecture of Gross, Pisarski and Yaffe regarding the reduction of QED to a sort of ϕ⁴ theory at high temperature. The leading high temperature contribution to the thermodynamic potential to all perturbativc orders: i) is given in terms of the dominant high temperature contribution to the two-point photon Green's function for zero frequency, ii) is shown to be both ultraviolet and infrared finite.     

Elementary particles

Abstract

The main property criteria which determine whether a certain material shall be used for a given application are discussed in general terms. The increase in cost of any given material in progressing through the various stages of processing and manufacture is outlined for steel. The general growth trends of production of a range of common metals, cement and plastics in the U.S.A. up to 1960 shows the very high growth rate of aluminium and plastics in recent years compared to other materials. It is shown that by considering the cost per unit of property required that a very useful index is given of the competitiveness of any given material. By way of example, typical costs for one ton of tensile strength given by a range of materials in various forms are tabled.

Some general observations are made on specific areas of conflict between materials, e.g. steel and concrete, aluminium versus steel, and plastics versus metals.     

转镜式高速相机扫描速度检测装置及不确定度评定

基于光电转换基本原理，设计并研制了用于转镜式高速扫描相机扫描速度的检测装置，包括均匀脉冲光源、精密双狭缝、超快响应光电转换器以及高带宽、高采样率数字示波器等。论述了检测装置的核心部件，用该装置实测了SJZ-15型转镜扫描相机名义扫速为4．5mm／μs的扫描速度，计算出了扫速不均匀性。按照国军标GJB3756，对检测装置的测量不确定度来源进行了分析，给出了该装置的不确定度评定方法及测量不确定度，对检测结果的评定表明，该检测装置的相对测量不确定度不大于0．1%，远低于目前转镜扫描相机的最大扫速不均匀性水平。实验证明，设计的检测装置具有很高的准确度和可靠性。     

Generalized finite compact difference scheme for shock/complex flowfield interaction

A class of generalized high order finite compact difference schemes is proposed for shock/vortex, shock/boundary layer interaction problems. The finite compact difference scheme takes the region between two shocks as a compact stencil. The high order WENO fluxes on shock stencils are used as the internal boundary fluxes for the compact scheme. A lemma based on the property of smoothness estimators on a 5-points stencil is given to detect the shock position. There is no free parameter introduced to switch the compact scheme and the WENO scheme. Some numerical experiments are given and they demonstrate that the present scheme has low dissipation due to the compact central differencing scheme used in the smooth regions.     

硅基底液晶光阀的理论和工艺研究

本文介绍了一种新型空间光调制器——硅基底液晶光阀。阐述了该器件的工作原理和各膜层的制备过程。最后提出了两种薄双面抛光片的方法,它们是实现该器件实用化的关键工艺。