THE MATRIX ANALYSIS FOR AN OPTICAL FREE-SPACE SWITCHING NETWORK AND AN OPTICAL CROSSOVER NETWORK WITH 4-FUNCTION INTERCHANGE NODES

A matrix analysis for free-space switching networks, such as perfect shuffle-exchange omega, crossover and Banyan is presented. On the basis of matrix analysis, the equivalence of these three switching networks and the route selection between input and output ports are simply explained. Furthermore, an optical crossover switching network, where MQW SEED arrays are used as electrically addressed four-function interchange nodes, is described and the optical crossover interconnection of 64 x 64, and high-speed four-function, interchange nodes is demonstrated in the experiment.

Chirped fiber Bragg gratings for optical fiber dispersion compensation

The use of alpha-power chirped fiber Bragg gratings for dispersion cancellation in an optical fiber link is discussed. Numerical and theoretical investigation of recompressing the dispersion-broadened pulse by using alpha-power chirped gratings is made, which shows that, the dispersion-broadened Gaussian pulse after 100 km standard fiber (with zero dispersion at lambda = 1.3 mu m) trnasmission at lambda = 1.55 mu m with initial width of T-FWHM = 33ps (full width at half maximum) can be perfectly recompressed with the peak reflectivity of 82% by using a 30 mm long alpha-power chirped fiber grating with proper a value and optimal grating parameters.

纳米硅薄膜的Raman光谱

通过等离子增强化学气相沉积法,制备了本征和掺磷的氢化纳米硅薄膜(nc-Si:H)，研究了晶粒尺寸和掺杂浓度对纳米硅薄膜喇曼谱的影响。结果表明晶粒变小和掺杂浓度增加都使纳晶粒的TO模峰位逐渐偏离声子限制模型的计算值。X射线衍射和高分辨电镜像的结果表明晶粒变小导致硅晶粒应力增加，而掺要使晶粒内部杂质和缺陷增多，这些因素破坏了晶粒变小导致晶粒应力增加，而掺杂使晶粒内部杂质和缺陷增多，这些因素破坏了晶粒内晶格的平移对称性进一步减小声子的平均自由程，导致实验值偏离理论计算值。晶格平称对称性的破缺还体现在，随晶粒尺寸减小或掺杂浓度增加，喇曼谱中TA、L���动模的相对散射强度增加。

Band properties of the transitional nucleus Pt-187

High-spin states in Pt-187 have been studied experimentally using the Yb-173(O-18, 4n) reaction at beam energies of 78 and 85 MeV. The previously known bands based on the nu i(13/2),nu 7/2(-)[503], and nu i(13/2)(2)nu j configurations have been extended to high-spin states, and new rotational bands associated with the nu 3/2(-)[512] and nu 1/2(-)[521] Nilsson orbits have been identified. The total Routhian surface calculations indicate that the transitional nucleus Pt-187 is very soft with respect to beta and gamma deformations. The band properties, such as level spacings, band crossing frequencies, alignment gains, and signature splittings, have been compared with the systematics observed in neighboring nuclei and have been interpreted within the framework of the cranked shell model. The rotational bands show different band crossing frequencies, which can be explained by the alignment either of i(13/2) neutrons or of h(9/2) protons. Importantly, evidence is presented for a pi h(9/2) alignment at very low frequency in the nu 7/2(-)[503] band. The proton nature of the band crossing is strongly suggested by comparing the measured B(M1;I -> I-1)/B(E2;I -> I-2) ratios with the theoretical values from the semiclassical Donau and Frauendof approach.

Application of uniform design and genetic algorithm in optimization of reversed-phase chromatographic separation

An optimization method based on uniform design in conjunction with genetic algorithm is described. According to the proposed method, the uniform design technique was applied to the design of starting experiments, which can reduce the number of experiments compared with traditional simultaneous methods, such as simplex. And genetic algorithm was used in optimization procedure, which can improve the rapidity of optimal procedure. The hierarchical chromatographic response function was modified to evaluate the separation equality of a chromatogram. An iterative procedure was adopted to search for the optimal condition to improve the accuracy of predicted retention and the quality of the chromatogram. The optimization procedure was tested in optimization of the chromatographic separation of 11 alkaloids in reversed-phase ion pair chromatography and satisfactory optimal result was obtained. (C) 2003 Elsevier B.V. All rights reserved.

空心纳米金在甲醛气体传感器中的应用研究

通过牺牲模板法合成了具有空心结构的纳米金催化剂,并进行了TEM、SEM和XRD等物理表征。把该催化剂作为工作电极的活性物质,以1mol/LKOH为电解质,组装了电流型甲醛气体传感器。在甲醛气体浓度为0～2.23×10-6mol/L���围内对传感器进行了性能测试,传感器响应信号y(A)与气体浓度x(mol/L)线性回归方程为y=16.63x+4.063×10-7,r=0.9989。该传感器灵敏度高于同载量实心金纳米催化剂组装的传感器70%左右,达到了降低贵金属用量的目的。因其具有较快的响应时间、良好的重现性和良好的线性关系等优点,可用于适当浓度范围内的甲醛气体检测。