微桥结构镍膜的弹性模量和残余应力研究

采用MEMS(MicroelectromechanicalSystems)技术研制了宽度在微米尺度的镍(Ni)膜微桥结构试样。采用纳米压痕仪(Nanoindenter)XP系统的楔形压头测量了微桥载荷与位移的关系,并结合微桥力学理论模型得到了Ni膜的弹性模量及残余应力,分别为190GPa和87MPa。与采用纳米压痕仪直接测得的带有硅(Si)基底的Ni膜弹性模量(186.8±7.5)GPa相符合。

Soluble Angiopoietin Receptor Tie-2 In Patients With Acute Myocardial Infarction And Its Detection By Optical Protein-Chip

The Tie-2 receptor has been shown to play a role in angiogenesis in atherosclerosis. The conventional method assaying the level of soluble Tie-2 (sTie-2) was ELISA. However, this method has some disadvantages. The aims of this research are to establish a more simple detection method, the optical protein-chip based on imaging ellipsomtry (OPC-IE) applying to Tie-2 assay. The sTie-2 biosensor surface on silicon wafer was prepared first, and then serum levels of sTie-2 in 38 patients with AMI were measured on admission (day 1), day 2, day 3 and day 7 after onset of chest pain and 41 healthy controls by ELISA and OPC-IE in parallel. Median level of sTie-2 increased significantly in the AMI patients when compared with the controls. Statistics showed there was a significant correlation in sTie-2 results between the two methods (r=0.923, P0.01). The result of this study showed that the level of sTie-2 increased in AMI, and OPC-IE assay was a fast, reliable, and convenient technique to measure sTie-2 in serum.

Influence of atomic densities on propagation property for ultrashort pulses in a two-level medium

The influence of atomic densities on the propagation property for ultrashort pulses in a two-level atom (TLA) medium is investigated. With higher atomic densities, the self-induced transparency (SIT) cannot be recovered even for 2π ultrashort pulses. New features such as pulse splitting, red-shift and blue-shift of the corresponding spectra arise, and the component of central frequency gradually disappears.

低密度台阶形闪耀光栅的制作

介绍了制作低密度闪耀光栅的过程,在制作时,对传统的制作过程进行了改进,有效提高了制作质量。以40μm闪耀光栅为例介绍了制作的过程,得到了良好的光栅表面形貌,并且闪耀级次的衍射效率达到了70%以上。相比传统的制作方法,效率提高了5%～10%。对比了理论上的衍射效率,分析了实验误差,发现把存在对准误差的光栅进行处理将会有效地提高其衍射效率,为进一步提高闪耀光栅的衍射效率提供了依据。

基于成像光通信的时间-空间扩频混合光码分多址编码方案

为了在成像光通信中充分利用时间和空间两种频带资源，以成像光通信为基础，提出一种利用二维光正交Pattern码结合时域扩频实现光码分多址（OCDMA）编码的新方案。分析在该方案中存在的多址干扰噪声，并给出了噪声的概率密度函数，然后讨论由多址噪声引起的误码率与判决门限、用户数、码长积和码重积之间的关系。在相同的码容量下与时域扩频光码分多址编码和空间扩频光码分多址编码方案相比，该方案能降低对相关器件性能（时域码片数量和空间像素规模）的要求，而且还可获得更小的误码率。最后给出编码一解码的光学实现方案。

Beam smoothing by lens array with spectral dispersion

A scheme of combining technology of lens array (LA) and smoothing by spectral dispersion (SSD) is introduced to improve the irradiation uniformity in laser fusion based on the earlier works on LA. The feasibility of the scheme is also analyzed by numerical simulation. It shows that a focal pattern with flat-top and sharp-edge profile could be obtained, and the irradiation nonuniformity can fall down from 14% with only LA to 3% with both SSD and LA. And this smoothing scheme is depended less on the incidence comparing to other smoothing methods. The preliminary experiment has demonstrated its effectiveness. (c) 2006 Elsevier B.V. All rights reserved.

Host dependent frequency upconversion of Er3+-doped oxyfluoride germanate glass

Er3+-doped oxyfluoride germanate glasses have been synthesized by the conventional melting and quenching method. The Judd-Ofelt intensity parameters were calculated based on the Judd-Ofelt theory and absorption spectra measurements. With the substitution of PbF2 for PbO, the Omega(2) parameter decreases, while the Omega(6) parameter increases. These change trends indicate that fluoride anions come to coordinate erbium cations and the covalency of the Er-O bond decreases. Structural and thermal stability properties were obtained by Raman spectra and differential thermal analysis, indicating that PbF2 plays an important role in the formation of glass network and has an important influence on the maximum phonon energy and thermal stability of host glasses. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions H-2(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2), and F-4(9/2) -> I-4(15/2), respectively, were simultaneously observed at room temperature. With increasing PbF2 content, the intensity of red (657nm) emissions increases significantly, while that of the green (525 and 546nm) emission increases slightly. The results indicate that PbF, has more influence on the red (657nm) emission than the green (525 and 546nm) emissions in oxyfluoride germanate glasses. The possible upconversion luminescence mechanisms have also been estimated and discussed. (c) 2005 Elsevier B.V. All rights reserved.

Structure and residual stress in gamma-LiAlO2, layer fabricated by vapor transport equilibration on (0001)sapphire

gamma-LiAlO2 layers with a highly preferred (1 0 0) orientation were prepared by vapor transport equilibration (VTE) technique on (0 0 0 1) sapphire substrate. Microststructure of the gamma-LiAlO2 layers was studied by XRD and SEM. In the temperature range from 750 to 1100 degrees C, the residual stress in the gamma-LiAlO2 layers varied from tensile to compressive with the increase of VTE temperature, and the critical point of the change between tensile and compressive stress is around 975 degrees C. (c) 2005 Elsevier B.V. All rights reserved.

Effects of Yb concentration on the fluorescence spectra of Yb-doped YAlO3 single crystals

0.5 at.% Yb:YAlO3(YAP), 5 at.% Yb:YAP and 15 at.% Yb:YAP were grown using the Czochralski method. Their absorption and fluorescence spectra were measured at room temperature and their emission line shape was calculated using the method of reciprocity. It was observed that the fluorescence spectra changed appreciably with the increasing of Yb concentration. For 0.5 at.% Yb:YAP, the line shape of fluorescence is very similar with the calculated emission line shape; with the increasing of Yb doping concentration, the line shape of fluorescence is very different from the calculated emission line shape. These phenomena are caused by the strong self-absorption at 979 and 999 nm for Yb:YAP. (c) 2005 Elsevier B.V. All rights reserved.

Growth and properties of ZnO thin film on beta-Ga2O3(100) substrate by pulsed laser deposition

Zinc oxide (ZnO) thin films were grown on the beta-Ga2O3 (100) substrate by pulsed laser deposition (PLD). X-ray diffraction (XRD) indicated that the ZnO films are c-axis oriented. The optical and electrical properties of the films were investigated. The room temperature Photoluminescence (PL) spectrum showed a near band emission at 3.28 eV with two deep level emissions. Optical absorption indicated a visible exciton absorption at room temperature. The as-grown films had good electrical properties with the resistivities as low as 0.02 Omega cm at room temperature. Thus, beta-Ga2O3 (100) substrate is shown to be a suitable substrate for fabricating ZnO film. (c) 2006 Elsevier B.V. All rights reserved.

Spectral properties and charge transfer luminescence of Yb3+ : Gd3Ga5O12 (Yb : GGG) crystal

The Yb (10%):GGG and Yb (30%): GGG crystals have been grown by the Czochralski method. The chemical compositions are: Yb1.07Gd1.74Ga5.19O12 and Yb0.33Gd1.47Ga5.2O12. The absorption and emission spectra of Yb:GGG crystal at room temperature have been measured. The spectroscopic parameters of Yb:GGG and Yb:YAG have been compared. Optical absorption spectra of Yb:GGG show 4f-4f transitions related to Gd3+ ion around 300 nm, and also an onset of charge transfer (CT) transitions from oxygen ligands to Gd3+ or Yb3+ cations below 240nm. The CT absorption of Yb3+ is largely overlapped by that of Gd3+ ions. (c) 2005 Elsevier B.V. All rights reserved.

Thermal-mechanical modeling of nodular defect embedded within multilayer coatings

The initiation of laser damage within optical coatings can be better understood by thermal-mechanical modeling of coating defects. The result of this modeling shows that a high-temperature rise and thermal stress can be seen just inside the nodular defect compared to surrounding coating layers. The temperature rise and thermal stress tend to increase with seed diameter. Shallower seed tend to cause higher temperature rise and greater thermal stress. There is a critical seed depth at which thermal stress is largest. The composition of the seed resulting from different coating-material emission during evaporation can affect the temperature rise and thermal stress distribution.

菊科蒿属与邻近属植物的研究

该成果系作者经近20年的研究，结合《中国植物志》第76卷2分册的编研，先后在全国大多数省区采集标本4000余号，在国内外标本馆参考鉴定标本4万多份，并以形态分类研究为主，结合形态解剖学、细胞学、孢粉学、谱系分支分析等多学科研究，将菊科春黄菊族区分为9大自然群，首次发表了“菊科蒿属演化系统”及“蒿属与邻近属间的亲缘关系”的新观点；首次系统的研究报导了中国蒿属植物186种，44变种，绢蒿属31种，3变种的系统分类、分布与主要经济用途等，发表了1新属、1新亚属、6新组、41新种、22新变种、38新组合种，64中国新分布记录种或变种；纠正前人错误鉴定或混乱35种；首次指出“蒿属自然群起源中心”在亚洲北方，“现代分布中心”在北温带及亚热带地区，而“现代分布区密集中心”在亚洲中部及东部地区的观点，首次报导了蒿属及邻近属在我国形成极为独特的“三斜带密集带谱”的分布规律和“横断山脉——喜马拉雅山脉”地区是一独特的区系分区，该地区既是蒿属植物冰期“避难所”，又是冰后期该属新分化衍生的次生种类的“次生起源中心”、“次生分化中心”及蒿属“第二个现代分布区密集中心”等独特见解。还分别报导亚、欧、非三洲蒿属区系含10亚区、28地区成份；绢蒿属含5亚区、8地区成份。从化学分类证实了原始组的种类多含“单萜类化合物”，略为进化组的种类多含“倍半萜类化合物”，而在进化组的种类则含苯环类化合物。研究成果达国际领先水平。