用数字干涉仪测量变形镜影响函数的实验研究

分析了变形反射镜面形影响函数的意义，鉴于自适应光学系统中波前探测大都以测量波前斜率为基础的特点，提出应研究斜率影响函数，并在此基础上构成波前复原矩阵。还介绍了用数字干涉仪测量变形镜影响函数的方法和结果，并对测量结果进行了分析，得到了影响函数的各种参数，例如：交连值，高斯指数，特征宽度等。并将干涉法测量斜率影响函数的结果与实际的哈特探测器的测试结果进行了比较。     

Colour symmetry double point groups

Thirty four distinct composition series arising out of the 32 crystallographic double point groups are employed to re-derive in a simple and elegant fashion all the 169 distinct colour symmetry groups generated by the 32 double point groups, exploiting the idea of colour generators. The advantage of the method employed and some possible applications of these colour groups are discussed. The resulting colour groups are tabulated.     

Indentation studies on 〈1 0 0〉, 〈0 0 1〉 and 〈1 0 1〉 face of ammonium dihydrogen phosphate (ADP) single crystals: A novel nonlinear optical material

In the present work, Vickers microhardness measurements were carried out on different faces i.e. (1 0 0), (0 0 1) and (1 0 1) of ammonium dihydrogen phosphate (ADP) single crystals grown by slow evaporation solution technique at room temperature in the load ranging from 0.2 to 2 N. The obtained results show that the load independent hardness values are 0.8, 0.7 and 0.66 GPa, respectively at different faces of ADP crystal. From the crack length measurements, the fracture toughness values (K_c) was estimated using Evans and Anstis model and the present studies suggest that Evans model is more relevant when compared to Anstis model. The load variation of some mechanical properties viz. brittle index number (B_i) and yield strength (σ_y) for ADP have also been calculated for the first time.     

A Quasi-3D Threshold Voltage Model for Dual-Metal Quadruple-Gate MOSFETs

Due to challenges with relentless scaling of conventional bulk complementary metal-oxide- semiconductor （CMOS） devices, non-conventional CMOS devices have been of great interest to scale metaboxide-semiconductor field effect transistors （MOSFETs） to the 32nm gate length and below effectively. Among non-conventional CMOS devices, quadruple-gate （QG） MOSFETs have been gaining interest because they are sup- posed to provide excellent electrostatic controllability for ultra-large-scale integration （ULSI） applications. A number of attempts have been made to analyze QG MOSFETs analytically with a great amount of success. Sharma et al. have presented an an- alytical threshold voltage model for QG MOSFETs using an isomorphic polynomial function for solv- ing the 3D Poisson equation. Chiang has presented a number of models of scaling length,threshold voltage and subthreshold current for QG MOS- FETs adopting a concept of the so-called equivalent number of gates （ENGs）.     

1 053-nm all-fiber pulse multi-pass stretcher using a linear chirped fiber Bragg grating

An all-fiber optical laser pulse multi-pass stretcher using a chirped fiber Bragg grating (CFBG) is demonstrated. Pulses from a 1 053-nm mode-locked fiber seed oscillator are stretched by multiple passing through a chirped fiber grating set in a fiber regenerative amplifier structure. We stretch the pulse from 16 ps to 1.855 ns after it transmits seven loops in the stretcher. The main factors that affect the stretching results are discussed.     

一种半球形天空亮度测量仪器的研制

在大气光学领域中,天空亮度分布有着重要的应用.简要介绍了天空亮度的测量原理,在分析同类测量仪器的基础上,提出了一种用于白天的,可见及近红外波段天空亮度测量仪器的设计,介绍了系统的组成和探测器的选择.经过定标,仪器能够得到天空亮度的绝对值,其结果反映了真实天空亮度分布的变化.该仪器弥补了传统的天空亮度测量仪器住测量波段、实时性、便携性等方面的不足,更好地满足了实际的科研需求.     

太阳米粒结构相关哈特曼-夏克波前传感模拟研究

基于互相关因子和绝对差分算法以及相关哈特曼－夏克波前传感器的基本原理，根据室内模拟太阳米料结构研究了低对比度扩展目标情况下应用相关哈特曼－夏克波前传感器探测波前误差的可行性，结果表明，相关哈特曼－夏克波前传感器能够有效探测光学波前误差。     

Structural and magnetic studies on spark plasma sintered SmCo5/Fe bulk nanocomposite magnets

SmCo₅+x wt% Fe (x=0$x=0$, 5 and 10) nanocomposite powders were synthesized by mechanical milling and were consolidated into bulk shape by spark plasma sintering (SPS) technique. The evolution of structure and magnetic properties were systematically investigated in milled powders as well as in SPS samples. A maximum coercivity of 8.9 kOe was achieved in spark plasma sintered SmCo₅+5 wt% Fe sample. The exchange spring interaction between the hard and soft magnetic phases was evaluated using δM–H measurements and the analysis revealed that the SPS sample containing 5 wt% Fe had a stronger exchange coupling between the magnetic phases than that of the sample with10 wt% Fe.     

An algebraic approach to the comparative study of the vibrational spectra of monofluoroacetylene (HCCF) and deuterated acetylene (HCCD)

Using the Lie algebraic method the vibrational energy levels of HCCF and HCCD are calculated for 102 and 110 vibrational bands, respectively, using the local Hamiltonian. A comparative study is made between the two. Better results are obtained than those published earlier from local mode analysis.     

Effect of acids on the gamma-radiolysis of frozen aqueous systems of some organic compounds

Abstract

ESR spectra of γ-irradiated frozen aqueous solutions of a number of organic compounds such as alcohols, ether, acetone and tetrahydrofurans have been examined in the presence and absence of mineral acids such as H₂SO₄. The presence of the acid is found to cause an intensification of the organic radical ESR spectra as compared with the acid free solutions. Also, the presence of the organic compounds in frozen aqueous H₂SO₄ suppresses the formation of both H-atoms and SO₄ ^? radical ions. These results have been explained on the basis of reactions of the electrons and holes, or excitons, primarily formed by the action of radiation on the substrate ice.