软X射线显微术及其用于生命科学研究概况

介绍了同步辐射软Ｘ射线显微术的基本原理和基本类型，举例说明了软Ｘ射线接触显微术、扫描显微术、全息显微术、相差显微术以及低温显微术在生命科学研究中的应用情况，简要介绍了国家同步辐射实验室软Ｘ射线显微术实验站的工作．     

无碎屑激光等离子体软X射线源的研究及应用前景

分析了常规金属靶激光等离子体源产生固体碎屑的原因及其对软Ｘ射线光学元件的危害，介绍了近年来发展起来的无碎屑激光等离子体软Ｘ射线源，归纳了无碎屑激光等离子体软Ｘ射线源的几种形式和特点，并且描述了这种新型光源在软Ｘ射线显微术及光刻术中的应用．     

同步辐射软X射线接触显微成像

软Ｘ射线显微术适合于自然状态下生物样品的高分辨率显微成像。软Ｘ射线接触显微术是Ｘ射线显微成像方法中最简单也是迄今唯一到接近理论分辨的方法。本文阐述软Ｘ射线接触显微成像的原理和方法，并报告用合理肥步辐射光源进行软Ｘ射线接触显微成像的一些实验结果。     

合肥同步辐射软X射线显微术研究

合肥国家同步辐射实验室首期建设的光束线之一用于软Ｘ射线显微成像研究。实验站现已装置初型的扫描透射Ｘ射线显微镜，并正在进行亲一代的扫描显微建设，同时还使同步辐射光进行接触软Ｘ射线呈微成像研究，并对选取的一些生物样品进行了成像试验。本文介绍了合肥同步辐射光源上软Ｘ射线显微术实验线站的建设及完成的一些实验结果。     

软X射线显微术活体材料成像的实验研究

软Ｘ射线显微术活体材料成像的实验研究蒋诗平张新夷阚娅付绍军徐向东单晓斌（中国科学技术大学国家同步辐射实验室，合肥２３００２９）陈建文徐至展陈敏（中国科学院上海光学精密机械研究所，上海２０１８００）软Ｘ射线显微术可以研究完整的不染色的活体细胞显微结构，...     

氦气环境中湿样品软X射线显微成像研究

介绍了在国家同步辐射实验室软Ｘ射线显微术实验站上利用氦气进行软Ｘ射线显微成像研究的理论依据、实验装置以及实验结果和意义。     

小型激光等离子体软X线－真空紫外辐射的研究

设计了一种小型激光等离子体软Ｘ线－真空紫外光源。该光源辐射强度高、波段覆盖宽、光谱连续平滑，其重复性、稳定性均优于±４．５％。适合在非同步辐射的一般实验室中使用。在亚微米光刻、软Ｘ射线显微术、真空紫外光谱学、薄膜光学常数测试等研究及应用技术领域具有广泛的实用价值。本文探讨了光源的辐射机制，给出了较理想的光谱测试结果。     

一些新型光电探测器扩展了应用领域

一些新型光电探测器扩展了应用领域《ＬａｓｅｒＦｏｃｕｓＷｏｒｌｄ）１９９６年３月号介绍了以下新型光电探测器及其应用１．电荷耦合器件（ＣＣＤ）ＣＣＤ原先是为天文和航天应用需要发展起来的成像器件。近些年来已广泛应用于拉曼谱、Ｘ射线成像、三维显微术和大容量...     

BiPbSbSrCaCuO非晶态及热处理对其影响

本工作用正电子湮没谱术（ＰＡＳ），Ｘ射线衍射谱（ＸＲＤ），示差热分析（ＤＴＡ），扫描电镜显微术（ＳＥＭ）和交流磁化率（Ｘａｃ）研究了Ｂｉ－Ｐｂ－Ｓｂ－Ｃａ－Ｃｕ－Ｏ非晶态和后续热处理的影响。结果表明：所研究的非晶态晶化温度Ｔｃ－４５０－４７０℃，当热处理温度Ｔａ＜Ｔｃ，非晶太经低温结构弛豫和高温弛豫。当Ｔａ＞Ｔｃ，在晶态多相体系中随温度升高发生低ｎ相向高ｎ相的转变，８５０℃退火可使超导转变温度...     

原子力显微术研究进展

原子力显微术是微纳米尺度实空间形貌成像与结构表征的关键技术之一。近些年,原子力显微术衍生发展出了一系列令人瞩目的功能化探测模式和新技术。文章从以下两个方面论述了原子力显微术的前沿进展:(1)原子力显微术的功能化探测模式及其在微纳米尺度物性研究与测量以及微纳加工等领域的应用;(2)原子力显微术自身在更高精度、更高分辨率、更快速度、更多功能等方面的进展及在基础和应用研究领域中的应用。文章还展望了原子力显微术的下一步发展方向和正在不断扩展的研究领域。     

Anisotropy of P Grain Boundary Segregation in a Rapidly Solidified Fe-0.6wt%P Alloy

P grain boundary segregation in an Fe-0.6wt%P alloy quenched from the melt was quantified by X-ray Mapping (XRM) in a Scanning Transmission Electron Microscope (STEM). The misorientation across the boundaries was determined by using ACT (Automatic Crystallography for TEM (Transmission Electron Microscopy)) and CBED (Convergent Beam Electron Diffraction). A significant range of the degree of P segregation to individual grain boundaries was found. Combination of chemical and structural studies provides evidence that P segregation to low-angle grain boundaries is reduced.     

The relationship between grain-boundary structure and segregation in a rapidly solidified Fe-P alloy

It is well known that the amount of solute segregation can vary from one grain boundary to another. Though it is accepted that this variation is due to differences in boundary structure and crystallography, direct correlation between the degree of segregation and specific boundary structural characteristics is not well documented. In the present paper, P grain-boundary segregation in rapidly solidified Fe was studied by X-ray mapping (XRM) in a scanning transmission electron microscope (STEM). The boundary structure was characterized by convergent beam electron diffraction (CBED). To explore the relationship between the degree of segregation and boundary structure, a parameter?β?is introduced, which describes how well the two crystal planes on either side of a grain boundary match each other in a manner similar to the long-established plane matching theory. The introduction of this parameter enables us to relate the degree of segregation to boundary structure in a consistent way, e.g., both small-angle and low?Σ?symmetric boundaries correspond to low angle of β, leads to a low degree of segregation.     

约束对Birkhoff系统Noether对称性和守恒量的影响

研究约束对Birkhoff系统的Noether对称性和守恒量的影响．首先，建立了Birkhoff系统的运动微分方程．其次，给出了系统Noether对称性的判据．然后，讨论了受约束作用后，Birkhoff系统的Noether对称性发生的变化，并给出了系统的Noether对称性以及守恒量保持不变的条件．最后，举例说明结果的应用． 关键词： 分析力学 Birkhoff系统 约束 Noether对称性 守恒量     

Faithful quantum secure direct communication protocol against collective noise

An improved quantum secure direct communication (QSDC) protocol is proposed in this paper.Blocks of entangled photon pairs are transmitted in two steps in which secret messages are transmitted directly.The single logical qubits and unitary operations under decoherence free subspaces are presented and the generalized Bell states are constructed which are immune to the collective noise.Two steps of qubit transmission are used in this protocol to guarantee the security of communication.The security of the protocol against various attacks are discussed.     

光学合成孔径系统的光束控制

本文给出真空中光学合成孔径系统光束控制的物理模型。计算机数值模拟结果与理论分析吻合。另外，对孔径的活塞型和倾斜型误差的影响也进行了探讨。     

导板光互连光斑位置偏移的研究

随着人们对信息处理与交换速度和容量提出的更高的要求,出现了光互连．它具有并行处理、传播速度快、信息量大、空间频带宽、串音小和能量损耗低等优点,因此它在光计算机和信息处理领域中成为越来越吸引人的课题［１～４］提出光电结合的计算机系统．实现光－电混合计算．ＳａｕｅｒＦ提出了将电子元件组成的电路板安装在光导板上的方法［５,６］．每个电路板除了包括计算机本身要求的功能外,还装上发射信号的光源和接收信号的探测器,借助全息元件的耦合,以光导板作为光信息交换的通道．这种互连方式传输信息,结合光电优点,利用Ｂｒ…     

基于激光的测量技术在燃烧流场诊断中的应用

分析了工业发动机湍流燃烧场诊断的需求和面临的挑战,介绍了燃烧流场组分浓度、温度和速度等主要参数的激光测量技术,给出了其基本原理、在燃烧场诊断中的应用和国内外研究现状,分析了不同技术的特点及其适用性。简介了多参数综合诊断的作用和进展。对目前诊断和测量存在的主要问题和发展趋势进行了探讨。     

Cylindrical-confinement-induced phase behaviours of diblock copolymer melts

The phase behaviours of diblock copolymers under cylindrical confinement are studied in two-dimensional space by using the self-consistent field theory. Several phase parameters are adjusted to investigate the cylindrical-confinement-induced phase behaviours of diblock copolymers. A series of lamella-cylinder mixture phases, such as the mixture of broken-lamellae and cylinders and the mixture of square-lamellae and cylinders, are observed by varying the phase parameters, in which the behaviours of these mixture phases are discussed in the corresponding phase diagrams. Fur-thermore, the free energies of these mixture phases are investigated to illustrate their evolution processes. Our results are compared with the available observations from the experiments and simulations respectively, and they are in good agreement and provide an insight into the phase behaviours under cylindrical confinement.     

Application of CO2 lasers in mechanical engineering technology in the USSR

Lasers are finding many applications in mechanical engineering in the USSR. The various types of lasers in use are investigated and the main properties of laser welding and cutting are studied and compared with other forms of these processes. Methods of surface treatment and heat hardening are also investigated.     

Electrostatic solitons in unmagnetized hot electron-positron-ion plasmas

Linear and nonlinear electrostatic waves in unmagnetized electron-positron-ion (e-p-i) plasmas are studied. The electrons and positrons are assumed to be isothermal and dynamic while ions are considered to be stationary to neutralize the plasma background only. It is found that both upper (fast) and lower (slow) Langmuir waves can propagates in such a type of pair (e-p) plasma in the presence of ions. The small amplitude electrostatic Korteweg-de Vries (KdV) solitons are also obtained using reductive perturbation method. The electrostatic potential hump structures are found to exist when the temperature of the electrons is larger than the positrons, while the electrostatic potential dips are obtained in the reverse temperature conditions for electrons and positrons in e-p-i plasmas. The numerical results are also shown for illustration. The effects of different ion concentration and temperature ratios of electrons and positrons, on the formation of nonlinear electrostatic potential structures in e-p-i plasmas are also discussed.