展宽器元件失调及带通分析

通过光线追迹法给设计的反射式单光栅展宽器建立了一个数学计算模型。利用这个数学模型计算和分析了元件失调对反射式单光栅展宽器二阶色散量和输出光束发散角的影响，并考虑了反射式单光栅展宽器中衍射光栅和球形凹面镜的尺寸与展宽器带通的关系。发现当平面反射镜M1的纵向偏离角为0．2°时．展宽器的二阶色散量最大，偏离角大于或小于0．2°时，展宽器的二阶色散量随之减小；得到了元件失调会增加输出光束发散角的结论；并发现展宽器中衍射光栅和球形凹面镜尺寸的有限大小对带通有限制作用。提出了利用反射镜M1纵向的适当偏离增大展宽器二阶

Near infrared broadband emission from bismuth-dysprosium codoped chalcohalide glasses

We investigate the broadband infrared emission of bismuth doped and bismuth/dysprosium codoped chalcohalide glasses. It is found that the bismuth/dysprosium codoping can drastically enhance the fluorescence as compared with either bismuth or dysprosium doped glasses. Meanwhile, the full width at half maximum of bismuth/dysprosium codoped glasses is over 170 nm, which is the largest value among all the reported rare-earth doped chalcohalide glasses. An ideal way for energy consumption between bismuth and dysprosium ions is supposed. Such improved gain spectra of both bismuth and dysprosium ions may have potential applications in developing broadband fibre amplifiers.

Structural role of fluoride in aluminophosphate sol-gel glasses: High-resolution double-resonance NMR studies

The local structure of Na-Al-P-O-F glasses, prepared by a novel sol-gel route, was extensively investigated by advanced solid-state NMR techniques. Al-21{F-19} rotational echo double resonance (REDOR) results indicate that the F incorporated into aluminophosphate glass is preferentially bonded to octahedral Al units and results in a significant increase in the concentration of six-coordinated aluminum. The extent of Al-F and Al-O-P connectivities are quantified consistently by analyzing Al-27{P-31} and Al-21{F-19} REDOR NMR data. Two distinct types of fluorine species were identified and characterized by various F-19{Al-27}, F-19{Na-23}, and F-19{P-31} double resonance experiments, which were able to support peak assignments to bridging (Al-F-Al, -140 ppm) and terminal (Al-F, -170 ppm) units. On the basis of the detailed quantitative dipole-dipole coupling information obtained, a comprehensive structural model for these glasses is presented, detailing the structural speciation as a function of composition.

NiFeMnO4系列热敏电阻的溶胶-凝胶制备技术研究

用溶胶-凝胶（Sol-gel）技术以及柠檬酸自燃方法制备了NiMn2.0-xFexO4（x=0、0．1、0．15、0．2、0．3）纳米氧化物粉体，并将得到的超细粉体进行压片、烧结、封装等工艺制得热敏电阻。用XRD、SEM、电阻测量等手段表征了烧结体材料的晶相、微观形貌以及电阻性能。电阻测量结果表明：随着铁离子的增加，所得热敏电阻的阻值增大。在所有获得的材料中，其灵敏度B值大于4300K，可认为是一种具有实际应用价值的负系数热敏电阻。

The effects of oxygen partial pressure on the optical absorption edge and the UV emission energy of ZnO films

The optical absorption edge and ultraviolet (UV) emission energy of ZnO films deposited by direct current (DC) reactive magnetron sputtering at room temperature have been investigated. With the oxygen ratio increasing, the structure of films changes from zinc and zinc oxide coexisting phase to single-phase ZnO and finally to the highly (002) orientation. Both the grain size and the stress of ZnO film vary with the oxygen partial pressure. Upon increasing the oxygen partial pressure in the growing ambient, the visible emission in the room-temperature photoluminescence spectra was suppressed without sacrificing the band-edge emission intensity in the ultraviolet region. The peaks of photoluminescence spectra were located at 3.06---3.15 eV. From optical transmittance spectra of ZnO films, the optical band gap edge was observed to shift towards shorter wavelength with the increase of oxygen partial pressure.

一种用于Yb：YAG激光器的波长分离膜的研制

以1030nm高反．940。980nm高透的波长分离膜作为实例，为提高该薄膜元件的波长分离效果，从膜系的优化方面做了一系列的研究。诸如采用带通滤光片的设计思想，在膜堆两侧加入了匹配层，调整膜堆的周期厚度，并用膜系设计软件对通带作进一步的优化。通过这一系列的优化设计后．利用RF双离子柬溅射工艺在BK7玻璃基底上沉积样品薄膜，并在基底背面加镀通带增透膜。结果显示，透射带在940和980nm处的透过率分别为97．73％和93．63％．反射带在1030nm的反射率为99．99％。对所制备的样品薄膜进行了激光损伤阈

EGRET伽马射线源光变的数值分析

高能γ射线天文是当今天体物理学中重要的研究领域之一，康普顿γ射线天文台的高能γ射线望远镜（EGRET）提供了大量的观测数据，发现了271颗高能γ射线点源，其中170颗未被证认．目前的研究表明，一些未证认源可能是活动星系核，银盘附近的一些未证认源可能与脉冲星和超新星遗迹（SNRs）有联系．也发现几个未证认源可能是星系扩散发射所造成的伪造源．但就像大家所讨论的那样，未证认源的数目比所期望的更多．这些未证认高能γ射线点源的基本物理特性是什么呢？以此为动机，利用不同的光变分析方法，对这些未证认源进行了仔细的统计分