单个波长到多个波长的变换实验

报道一种波长变换的新方法.采用此方法不需要任何泵浦光便能够直接将信号光变换成在特定谱宽内的任意多个任意波长的变换光,这对于将来的波分复用光网络提供了较大的方便.此波长变换的原理是利用色散位移光纤的非线性效应产生超连续光谱(SC)信号,由于这种SC信号携带有变换光信号,对这种连续谱进行滤波便能够得到所需要的任意频率的变换信号.此变换方式具有变换频带宽,偏振不敏感的优点。     

线圈型全光纤偏振器的研究

本文采用等效电流法对线圈型全光纤偏振器进行了分析计算.对应于保偏光纤中两正交传输基模的消光比,提出了一种分析保偏光纤弯曲损耗的新方法,这种方法基于将保偏光纤两个不同偏振模式分别等效为两个普通圆光纤的基模,等效参数通过测量不同偏振模式的模场半径来确定.实验证明这种理论计算方法与实验结果一致.最终,我们研制出的线圈型光纤偏振器在1.31μm工作波长下,实测消光比达30dB以上,工作偏振模式插入损耗≤3dB.     

准直小孔法自动调焦在激光直写入系统中的应用

本文介绍了一种新的自动调焦方法准直小孔法.对自动调焦的原理和后继电路处理方法作了详细的分析.它具有响应时间短、灵敏度高,能够很好的在激光直接写入系统中克服物镜工作台运动中导轨的不平和轴向窜动所造成的离焦。     

氯化钠团簇的形成规律与结合能计算

当离子蒸气冷凝形成团簇时，其结构表现出特定的规律。文中对不同大小不同形状的氯化钠团簇结构与结合能进行了计算，以求揭示离子蒸气冷凝形成团簇的一些规律，并与实验结果进行对照。     

微型圆光栅刻划偏心量的控制

对微型圆光栅刻划偏心误差问题进行了讨论。提出了微型圆光栅刻划时偏心调试误差的公差范围。     

Magnetism in very thin films of permalloy measured by spin polarized cascade electrons

The spin polarizationP of the low energy cascade electrons excited with a primary unpolarized electron beam is measured with ultrathin films of permalloy (Ni₈₀Fe₂₀) as a function of film thickness, external magnetic field, and temperatureT. Surface adsorbates of small concentrations of less than 10% of a monolayer can change the Curie point and the saturation value ofP ₀(T0) by as much as 30%. The Ta-substrate induces a magnetically dead region in permalloy. Conventional spin wave theory cannot account for the observed smallT-dependence of the magnetizationM. Films on a nonmagnetic substrate are compared to similar films coupled to bulk permalloy over an interface of Ta. TheT-dependence ofM with the coupled films can be explained by spin wave theory. At lowT, the films coupled to the bulk exhibit a faster decrease ofM than the uncoupled films. We propose that this thermal stabilization of the magnetization in very thin ferromagnetic films is due to quenching of the long wavelength spin modes.     

XPS investigations of ink‐jet printed paper

Different ink‐jet printed paper materials were investigated using X‐ray photoelectron spectroscopy (XPS) yielding the elemental composition of the near‐surface region of the papers. We found significant differences with respect to the detected elements and their atomic concentrations in the different inks studied here. Two different groups of inks could be identified by means of a lower ratio of the O and C atomic concentrations and lower concentrations in specific trace elements like Mg, Na and Si. High‐resolution spectra of C 1s and O 1s core levels allowed a detailed determination of the chemical state of the respective elements. On the basis of a detailed deconvolution of these XPS signals, significant differences between all the investigated ink‐jet printed papers were found, thereby allowing their discrimination. The applicability of the measurements and, more generally, the XPS technique for forensic investigations of paper are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Chiral Salen Manganese Complex Immobilized on SBA-15： A New Heterogenized Enantioselective Catalyst for the Epoxidation of Alkenes

Jacobsen‘s catalyst was immobilized onto SBA-15 by multi-step grafting, and this heterogenized catalyst exhibited comparable catalytic performance with the corresponding homogeneous counterpart for the epoxidation of alkenes, and the catalyst could be recycled effectively several times.     

双邻苯二酚锑二甲基羟乙铵的晶体结构

含锑配合物是治疗血吸虫病、肿瘤等的常用药物,我们曾对双邻苯二酚锑二乙基羟乙胺进行了晶体结构测定,本文简要报导双邻苯二酚锑二甲基羟乙胺的结构.锑化合物的制法与其二乙基羟乙铵衍生物类似.产物为淡黄色晶体,它在水溶液中长时间放置会变成紫黑色,因此,制得的晶体须立即用丙酮溶解进行重结晶.晶体的密度为1.667g/cm~3.按C_(16)H_(20)O_5NSb的元素分析结果(％)如下:Sb 28.3(28.5),C 43.9(44.9),N 3.3(3.3),H 4.7(4.7).括号内为理论值.