先进燃烧室涡流杯流场计算

本文采用贴体坐标系（Ｂｏｄｙ－ＦｉｔｔｅｄＣｏｏｒｄｉｎａｔｅＳｙｓｔｅｍ）数值研究先进燃烧室涡流杯内速度场和紊流特性,并利用ＴＴＭ法生成贴体网格。由于双级旋流器形状复杂,本文提出了型线定点法来确定边界网格、ｕｖ线法生成交错网格以及整体不分区进行流场计算。计算结果表明;计算方法合理,计算机程序是可靠的。     

采用高分辨率高精度格式求解跨音压气机转子内三维粘性流场

采用一种新型的ＬＵ隐式算法及４－５阶高分辨率ＴＶＤ格式求解了叶轮机械内的三维Ｎ－Ｓ方程和ｑ－ｗ湍流模型。应用几何法与ＰＤＦ方法混合的网格生成程序,得到了ＲＯＴＲＯ３７跨音速压气机转子内的Ｈ型网格,并将数值模拟的结果同ＬＤＶ实验值进行了比较。     

水轮机蜗壳和固定导叶内部三维紊流流场数值研究

1引言用数值方法研究蜗壳和固定导叶内部流场是改进和优化蜗壳和固定导叶设计的一个重要手段。早期的数值研究大多基于势流理论[1～2]，随着计算机技术和计算流体动力学的迅速发展，蜗壳和固定导叶内部三维紊流的数值分析已经成为可能t’－’］。本文以三峡水轮机组内部流动的研究为背景，基于N－S方程和标准的k一。紊流模型，采用贴体座标和交错网格系统，用SIMPLEC算法对三峡模型机组蜗壳和固定导叶内部的流动进行数值模拟，提出设计工况时蜗壳和固定导叶内三维素流数值模拟计算结果，为改进蜗壳和固定导叶设计提供了一些有益的参考资…     

基于车身外形CAD数据的表面氯动网格生成

提出一种在非均匀参数空间上生成表面数值网格的方法,开发了相应的表面网格生成软件ＳＧＲＩＤ,并应用于汽车动力学计算机仿真中具有复杂几何外形的车射表面网格生成。     

含甲硫氨酸二肽的单电子氧化反应：激光闪光光解研究

运用２４８ｎｍ激光光解瞬态吸收光谱研究了中性水溶液中丙氨酰甲硫氨酸（Ａｌａ－Ｍｅｔ）和Ｎ－甲酰甲硫氨酰色氨酸（Ｎ－Ｆｏｒｍｙｌ－Ｍｅｔ－Ｔｒｐ）的单电子氧化反应过程,分别观察到「Ｓ∴Ｓ」＾＋和「Ｓ∴０」含硫三电子键的生成,但在Ｎ－甲酰甲硫氨酰色氨酸体系中没有观察到「Ｓ∴Ｎ」＾＋的生成。提出了「Ｓ∴Ｓ」＾＋和「Ｓ∴０」含硫三电子键的生成机理,认为Ｎ－甲酰甲硫氨酰色氨酸体系不能生成「Ｓ∴Ｎ」＾＋三电子     

激光引发DNA及多聚核苷酸与SO4.-作用的闪光光谱研究

运用２４８ｎｍ激光光解瞬态吸收光谱研究了ＳＯ４·－与ＤＮＡ及其核苷酸和多聚核苷酸ｐｏｌｙ［Ｇ］、ｐｏｌｙ［Ａ］和ｐｏｌｙ［Ｃ］的相互作用,观察了各体系的作用过程,结果表明,ｐｏｌｙ［Ｇ］、ｐｏｌｙ［Ａ］与ＳＯ４·－发生单电子氧化反应生成嘌呤端基自由基;ｄＣＭＰ与ＳＯ４·－单电子氧化生成阳离子自由基,随后与水反应生成５－羟基－６Ｃ自由基;而ｐｏｌｙ［Ｃ］,ＳＯ４·－先在碱基上加成,生成的加成自由基再从核糖上抽氢生成Ｃ２’－糖自由基;ＤＮＡ与ＳＯ４·－作用生成的主要瞬态产物是鸟嘌呤端基自由基。     

用多重网格TVD－LW格式数值求解N－S方程

用多重网格ＴＶＤ－ＬＷ格式数值求解Ｎ－Ｓ方程刘建军，蒋洪德（中国科学院工程热物理研究所北京１０００８０）关键词：ＴＶＤ－ＬＷ格式，Ｎ－Ｓ方程一、前言用时间推进法数值求解雷诺平均Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，不仅能够模拟从低亚音速到高超音速的复杂定常...     

非结构网格生成Bowyer—Watson方法的改进

完善了应用Ｄｅｌａｎｎａｙ原理生成非结构网格的Ｂｏｗｙｅｒ－Ｗａｔｓｏｎ方法。通过求解简化Ｐｏｉｓｓｉｏｎ方程，灵活地控制网格的疏密，通过网格层次的区分，提高了网络的贴体性能；并通过分区，实现了适用于粘流计算的网格生成。     

网格间距及正交性控制在翼—身—尾组合体三维绕流中的研究

用椭圆型方程生成网络。在二维发展两种Ｈｉｌｅｎｓｔｏｃ方法实现对网格与边界间距及与边界正交的控制，并将其思想推广到三维，生成了翼－身－尾组合体与公共交界或边界面正交的三维贴体分块网格，用于Ｅｕｌｅｒ方程流场计算，效果良好。     

飞机构型Euler绕流结构网格方法计算的可信度

采用三种方法验证飞机构型Ｅｕｌｅｒ绕流结构网格方法计算。第一,同一网格,采用不同的方法或程序进行计算,采用Ｊａｍｅｓｏｎ中心差分有限体积方法和Ｓｔｅｇｅｒ－Ｗａｒｍｉｎｇ流量分裂迎风格式有限体积方法,为计算提供容错手段;第二,网格细化和网格点重新分布,并通过网格收敛指标进行评估;第三,提出新的多块拼接网格拓朴,采用不同的网格拓扑进行计算。     

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.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

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.     

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.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

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.