微桥结构Ni膜杨氏模量和残余应力研究

采用MEMS(MicroelectromechanicalSystems)技术研制了镍(Ni)膜微桥结构试样,应用陶瓷压条为承力单元,与纳米压痕仪XP系统的Berkovich三棱锥压头相结合,解决了较宽Ni膜微桥加载问题。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膜微桥的杨氏模量及残余应力,其值分别为190.5GPa和146MPa,与应用纳米压痕仪直接测得的带有Si基底的Ni膜杨氏模量186.8±7.34GPa相吻合。

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.

激光冷却铷原子喷泉钟的微波谐振腔设计

对自行研制的激光冷却铷原子喷泉钟的微波谐振腔进行了分析和设计，确定了需要的微波谐振腔基本参数。对影响微波谐振腔共振频率的因素进行了分析和研究，得到了共振频率随环境因素的变化规律。这些对调节微波腔共振频率和提高原子钟的准确度有重要意义。还对研制的微波谐振腔进行了测试，结果表明微波谐振腔的性能满足激光冷却铷原子喷泉钟的要求。由测试结果进一步估算了微波谐振腔引起的横向腔相移。

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.

磷酸盐激光玻璃的化学机械抛光

从磷酸盐激光玻璃的成分和结构出发,分析了其化学机械抛光(CMP)机制。通过实验验证了磷酸盐激光玻璃对抛光液pH值具有较强的选择性,在微酸性和中性条件下磷酸盐激光玻璃具有较高的抛光效率,在抛光液中添加pH值调节添加剂会保持抛光环境的酸碱性从而影响抛光效率和抛光质量。通过对pH值和抛光剂浓度的控制获得了均方根(RMS)优于0.6 nm的磷酸盐激光玻璃的超光滑表面。

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.