环形光栅的菲涅耳衍射

在圆孔的菲涅耳衍射的基础上 ,讨论环形光栅的菲涅耳衍射 ,并给出了计算机仿真结果     

注入锁定铜蒸气激光器的实验研究

使用两台相同的望远镜式非稳腔铜蒸气激光器,通过一块45°玻璃平板作腔的耦合组成匹配的注入锁定系统,研究了同步、注入信号功率和光束孔径大小等因素对输出功率和方向性的影响,实验结果清楚地表明,注入信号的作用在于抑制腔内高阶横模(包括被放大的自发发射)的竞争,使高增益介质的激光器既提高效率又改善方向性。注入锁定器件功率水平在5左右的情况下,其结果与单独非稳腔振荡相比,输出功率增加30～40％,方向性改善一倍以上。     

Hyperfine Field and Isomer Shift Evolution in Hydrogenated Nd–Fe–B Alloy

RE₂Fe₁₄B (RE=rare earth) materials are capable of absorbing hydrogen to form a stable solid solution at room temperature. Hydrogenation produces a number of significant changes in the hyperfine interactions. In this work, ⁵⁷Fe Mössbauer effect spectroscopy and X-ray diffraction measurements were performed on Nd_14.01Hf_0.08Fe_78.91B_7.00 alloys submitted to thermal treatment in hydrogen atmosphere. A non-linear increase of the hyperfine fields and isomer shifts with hydrogen concentration was observed. The hyperfine parameters of the 8j₁ site exhibit a rather different evolution than those experienced by the other major sites (8j₂, 16k₁, 16k₂). The origin of the hyperfine field enhancement is analyzed in terms of volume expansion and H nearest neighbors to the Fe sites. A linear expression on these two effects to give account of isomer shift evolution for 8j₁ site is given.     

红外系统后向反射光的光强研究

根据衍射光学理论分析了红外系统后向反射光强的分布,反射区域可以分成近场传输区域、菲涅耳衍射区域和夫琅和费衍射区域。在菲涅耳衍射区域内,反射光斑中心光强是呈明暗变化的,反射光斑中心光强在0～1km内剧烈振荡,1～3km之间达到峰值,然后随传输距离的继续增加,反射光斑中心光强逐渐减小。在夫琅和费衍射区域内,光斑图像中央是亮光斑,周围环绕着明暗交替的圆环。     

羊八井50m2RPC实验及初步测试结果

介绍了羊八井50m²电阻板室(RPC)地毯实验的结构、安装和对其性能的初步测试.测试的结果表明RPC完全能够很好地在海拔4300m,气压594mbar的羊八井宇宙线观测站正常地运行.     

微波分光仪上双缝干涉实验中参数的选取

双缝干涉和双缝衍射其本质都是相干波的迭加,干涉和衍射没有严格的固定分界线。实验中为充分体现双缝干涉特征及规律,应恰当地选择和设定实验参数,并对双缝干涉的实验结果与杨氏双缝干涉及双缝衍射的结果进行对比讨论     

全息照相及其开拓

激光全息摄影技术集几何光学、波动光学和信息光学为一体,为光学的研究展示了美好的前景。本文给出了从激光全息照相到彩虹全息、θ调制、偏振光干涉等实验的原理和过程。     

Surface site dependence to negative ion formation

The processes of electron transfer and dissociative scattering are explored for collisions of hyperthermal NO⁺ on GaAs(110). The experiments reveal a marked angular dependence to O⁻ emergence. A strong correlation between the O⁻ scattering angle and the final atom-surface interaction site provides a map of the lateral dependence to reactivity. The results are modeled by sequential neutralization, dissociation, and electron attachment steps. Classical trajectory calculations, in conjunction with an empirical opacity function, accurately reproduce the experimental results. The opacity function is interpreted as the probability that an electron will attach to a departing O fragment as a function of the last surface site the atom impacts. The experiments indicate that O⁻ emergence occurs predominantly for oxygen atoms which come in close contact with the localized dangling bond states of GaAs(110).     

二元光学在激光测距中的应用

利用二元光学器件的相位补偿作用进行波面变换,将高斯光束变换为平面光束,达到减小激光测距仪光束发散角的目的。在２０ｋｍ 处对激光光束发散角采用叠加积分衍射分析进行计算,得到结果为２ ×１０ － ４ｍｒａｄ , 远小于原来的２ｍｒａｄ 。计算还表明测程没有因能量损失而降低。     

Properties of solvent-free perylene iodine

The perylene iodine system was prepared by a vapour-phase reaction without the use of solvents. Compositions between peryleneI₂ and peryleneI₆ were synthesized and studied by gravimetric analysis, infrared spectroscopy, X-ray diffraction and temperature-dependent resistivity measurements. Infrared spectra in the region 400–4000 cm⁻¹ taken after different amounts of iodine were removed from the sample are distinct from perylene with new absorption lines at 1551 and 1302 cm⁻¹ and shifts of some perylene frequencies. Powder X-ray diffraction measurements indicate that the lattice is monoclinic with parameters a=11.65 Å, b=10.85 Å, c=10.1 Å, β=100.5°. The (1 0 0) reflection, which is forbidden in the space group of perylene, is observed from the compound. The material is electrically conductive and obeys Ohm's law at high temperatures. At low temperatures and high currents, nonlinear effects are observed. The conductivity of the material increases to 1.0 (Ω cm)⁻¹ at room temperature as the iodine content increases to a composition of peryleneI₆. The resistivity obeys an exponential temperature dependence.