用网格衰减膜相对标定SIOFM─5FW软X光底片

点聚焦激光等离子体发出的Ｘ射线经晶体色散形成均匀的单色Ｘ射线源，在此基础上，用单层网格作为衰减膜，得到未经衰减和经过衰减的Ｘ射线谱，对无保护膜ＳＩＯＦＭ５ＦＷ软Ｘ光底片作了试验性的相对标定，得到了０．９１ｎｍ波长的特性曲线     

三角形弯晶单色器的分光及聚焦特性研究

北京同步辐射装置(BSRF)的4W1C光束线用斜切角为12.16°的三角形Si(111)、Si(220)和Si(422)晶体在衍射角为23.65°时选择0.252nm、0.154nm和0.089nm波长的单色X光.三角形晶体压弯成柱面,可实现单色光水平方向的聚焦,为漫散射实验站提供聚焦的单色X光.解析计算和SHADOW软件包进行追踪的结果与实验测试结果符合得很好.     

荧光XAFS研究Si可稀浓度杂质的区域结构

荧光ＸＡＦＳ研究Ｓｉ晶体中等电子，缺电子和富电子杂质原子的区域环境结构。结果表明杂质原子的电子构型决定了杂质原子对Ｓｉ区域晶格形变的影响。相对于共价键长ＲＳｉ－Ｓｉ（０．２４０ｎｍ）来说，富电子杂质Ａｓ导致Ｓｉ晶格在Ｓｉ（１１１）方向的ＲＡｓ－Ｓｉ键长产生０．００４ｎｍ的反应增长，等电子杂质Ｇｅ的Ｒ－Ｇｒｅ－Ｓｉ和缺电子杂质Ｇａ和ＲＧａ－Ｓｉ键长收缩０．００２ｎｍ。     

用网格衰减膜相对标定SIOFM—5FW软X光底片

点降焦激光等离子体发出的Ｘ射线经晶体色散形成均匀的单色Ｘ射线源，在此基础上，用单层网格作为衰减膜，得到未经衰减和经过衰减的Ｘ射线谱，对无保护膜的ＳＩＯＦ－Ｍ５ＦＷ软Ｘ光底片作了试验性的相对标定，得到了０．９１ｎｍ波长的特性曲线。     

1.55μmSi_(1-x)Ge_x光波导与Si_(1-x)Ge_x/Si多量子阱探测器集成的优化设计

对１．５５μｍ波长的Ｓｉ１－ｘＧｅｘ光波导和Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱（ＭＱＷ）红外探测器的集成器件结构进行了系统的分析和优化设计。优化结果为：１）对Ｓｉ１－ｘＧｅｘ光波导，Ｇｅ含量ｘ＝０．０５，脊宽、高和腐蚀深度分别为８、３和２．６μｍ；２）对Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器，Ｇｅ含量ｘ＝０．５，探测器由厚度为５５０ｎｍ、２３个周期的６ｎｍＳｉ０．５Ｇｅ０．５＋１７ｎｍＳｉ组成，长度约２ｍｍ。结果表明，这种结构器件的内量子效率可达８８％。     

五氧硼酸钾结构的~1H NMR研究

给出相对于外磁场不同取向的五氧硼酸钾（ＫＢ５）单晶的１ＨＮＭＲ室温谱．发现当外磁场在晶体的ｂｃ平面里，１ＨＮＭＲ谱最多有６个峰．而在ａｈ或ａｃ平面里，最多仅有５个峰．用计算机拟合ＮＭＲ谱表明：在五氧硼酸钾中，氢原子是以羟基和水分子集团的形式存在．在羟基集团中，Ｏ—Ｈ的距离为０．１００５±０．００１ｎｍ和０．１０５４±０．００１ｎｍ；而在水分子中，Ｏ—Ｈ的距离为０．０９８３±０．００１ｎｍ和０．０９６８±０．００１ｎｍ，并且Ｈ—Ｏ—Ｈ夹角为１０８°±１°．这些显示本文的数据与中子衍射结果相近，而Ｘ射线衍射所得到的质子位置的数据则与我们的结果相距甚远．     

热稳定法拉第旋转TbYbBiIG磁光单晶及性能

采用高温溶液法，以Ｂｉ２Ｏ３／Ｂ２Ｏ３为助熔剂成功地生长出掺铋复合稀土铁石榴石（ＴｂＹｂＢｉ）３Ｆｅ５Ｏ１２（简称ＴｂＹｂＢｉＩＧ）晶体。晶体外形规则，最大尺寸为７×６×４ｍｍ３，Ｘ射线衍射分析证实，生长的晶体为ＴｂＹｂＢｉＩＧ单相单晶体，扫描电镜能谱分析其组成为Ｔｂ２．０６Ｙｂ０．４６Ｂｉ０．４８Ｆｅ５Ｏ１２。在１．０μｍ～１．７μｍ波段测量出晶体法拉第旋转谱和光吸收谱。当λ＝１．５５μｍ时，在１０°Ｃ～８０°Ｃ温度范围内测得法拉第旋转θＦ的温度系数为ｄθＦ／ｄＴ＝－２．３×１０－２ｄｅｇ·ｍｍ－１Ｋ－１。研究结果表明，ＴｂＹｂＢｉＩＧ单晶体在近红外波段θＦ约为ＹＩＧ单晶的３倍，温度系数小，是制作高性能光隔离器的一种好材料     

北京同步辐射装置X射线漫散射实验站及准周期非晶多层膜的X射线非镜面散射研究

讨论了北京同步辐射装置的４Ｗ１Ｃ光束线和Ｘ射线漫散射实验站的技术特点．利用在漫散射实验站上获得的能量分辨率为４．４×１０－４、光斑大小为０．５ｍｍ（水平）×０．３ｍｍ（垂直）的聚焦单色Ｘ射线光束，研究了准周期非晶多层膜的Ｘ射线漫散射──非镜面散射．实验结果表明，准周期多层膜的漫散射强度分布在倒空间中与表面平行的条纹上并形成散射强度的调制．对散射强度调制进行的模拟计算得到相当满意的结果．     

1.55μmSi1—xGex光波导在Si1—xGex／Si多量子阱探测器集成的优…

对１。５５μｍ波长的Ｓｉ１－ｘＧｅｘ光波导和Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器的集成器件结构进行了系统的分析和优化设计。优化结果为：１）对Ｓｉ１－ｘＧｅｘ光波导，Ｇｅ含量ｘ＝０．０５，脊宽，高和腐蚀深度分别为８，３和２．６μｍ，２）对ＳＩ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器，Ｇｅ含量ｘ＝０．５，探测器由厚度为５５０ｎｍ，２３个周期的６ｎｍＳｉ０．５ＧＥ０．５＋１８ｎｍＳｉ组成，长度约２ｍｍ。     

用平场光栅谱仪现场标定5FW X光底片

采用像散模式的平场光栅谱仪作为分光元件，点状镁激光等离子体Ｘ射线源为原始光源，获得均匀线性单色较Ｘ射线再生源，在此基础上，用多阶梯衰减膜为相对曝光强度标尺，现场标定了上海感光胶片厂生产的５ＦＷ无保护膜Ｘ光底片，给出了５．０ｎｍ～８．０ｎｍ间的底片响应特性。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.