双原子分子体系传能机制的分子动力学模拟

本文应用分子动力学计算机模拟方法研究同核双原子分子晶体体系的内部传能机制。计算了不同势参数下分子内部的振动频率;验证了振动势能项将以与平动、振动、转动各自由度一样的权重分配分子能量的理论;计算了不同振动频率下的弛豫速率。

Stress-distribution at the rigid circular-arc inclusion end

The elastic plane problem of a rigid co-circular arc inclusion under arbitrary loads is dealt with. Applying Schwarz's reflection principle integrated with the analysis of the singularity of complex stress functions, the general solution of the problem is found and several closed-form solutions to some problems of practical importance are given. Finally, the stress distribution at the arc inclusion end is examined and a comparison is made with that of the rigid line inclusion end to show the effect of curvature.

低能离子束方法制备磁性Fe-Si合金薄膜

　利用质量分离的低能离子束技术,获得了磁性Fe Si合金薄膜。利用俄歇电子能谱法(AES)、X射线衍射法(XRD)以及交变梯度样品磁强计(AGM)测试了样品的组分、结构以及磁特性。测试结果表明在室温下制备的Fe Si合金是Fe组分渐变的非晶薄膜,具有室温铁磁性。当衬底温度为300℃时制备的非晶Fe Si薄膜中有Fe硅化物FeSi相产生,样品的铁磁性被抑制。

第四届世界生物力学大会简介

"第四届世界生物力学大会"(4~(th)World Congress on Biomechanics)于2002年8月3~11日在加拿大卡尔加里(Calgary,Canada)召开．会议主办单位为卡尔加里大学，参会人数约1 600人．参加会议的主要国家包括：美、英、德、日、加、意、法、中国和中国香港等50余国家和地区．会议交流的论文篇数约为1680篇(含口头报告及墙展)．中国中科院力学所、中日友好医院、四川大学、重庆大学等6位学者参加了本次会议．所发表的工作分别涉及细胞与分子生物力学、假肢生物力学、白细胞力学-生物学耦合、血流动力学等方面，其研究工作在整体上符合当前本领域的发展方向，有的工作具有国际竞争性，会议的反响是肯定的．作者在"分子与细胞生物力学"(Molecular and Cellular Biomechanics)分会上做了口头报告和墙报展讲．

第11届国际快淬和亚稳材料会议简介

第11届国际快淬和亚稳材料会议于2002年8月24~30日在英国牛津大学召开，本次会议由牛津大学材料系承办． 200多名来自欧洲、美国、加拿大、日本、韩国、印度、巴西、澳大利亚、新西兰、中国等29个国家的代表参加了本次大会．会议宣读口头报告244篇，张贴论文117篇，其中包括大会报告11篇，邀请报告31篇．会议论文经严格评审后由Materials Science and Engineering A杂志选择收录．下届会议将于2005年在韩国举行．

第十四届国际近海与极地工程学术会议简介

国际近海与极地工程学术会议(International Offshore and Polar Engineering Conference)是每年一度由国际近海与极地工程学会主办的旨在促进近海工程、极地工程等领域的科技进步以及国际间学术交流与合作的大型国际学术会议.

铌酸锂晶体紫外激光诱导畴反转实验研究

报道了在铌酸锂晶体中实现紫外激光诱导畴反转的实验。在一定外加均匀电场下，铌酸锂晶体中通过波长365nm的紫外激光，由于紫外光的照射降低了矫顽电场只在通光区实现畴反转。研究表明，该方案可用于周期性极化铌酸锂的制备，并有望成为制作精细周期性畴结构的有效技术方案。

Computation of the ambiguity function for circularly symmetric pupils

A method of computing the ambiguity function (AF) for a circularly symmetric pupil function is presented. The AFs of a clear aperture and two shaded apertures are considered in detail and an explicit expression for the first of these AFs is given. We explain these results in the context of the well-known optical transfer function theory and show a primary application of these computations. A good analytic approximation is also introduced, providing an alternative method for calculating the AF, in a simpler way.

Effect of wavelength of sensitizing light on holographic storage properties in LiNbO3 : Fe : Ni crystal

By sensitizing with 514 nm green light, 488 nm blue light and 390 nm ultraviolet light, respectively, recording with 633 nm red light, effect of wavelength of sensitizing light on holographic storage properties in LiNbO3:Fe:Ni crystal is investigated in detail. It is shown that by shortening the wavelength of sensitizing light gradually, nonvolatile holographic recording properties of oxidized LiNbO3:Fe:Ni crystal is optimized gradually, 390 nm ultraviolet light is the best as the sensitizing light. Considering the absorption of sensitizing light, to obtain the best performance in two-center holographic recording we must choose a sensitizing wavelength that is long enough to prevent unwanted absorptions (band-to-band, etc.) and short enough to result in efficient sensitization from the deep traps. So in practice a trade-off is always needed. Explanation is presented theoretically. (c) 2005 Elsevier GmbH. All rights reserved.

中国古代釉砂和玻砂

釉砂和玻砂是古玻璃的前身,和古玻璃相比有着不同的成分组成和化学结构.考古资料显示中国釉砂和玻砂的持续时间自西周初期至东汉时期.用质子激发X荧光技术和电感耦合等离子体发射光谱分析了几个出土于中国内蒙古、甘肃、河南的釉砂和玻砂管珠的化学成分.用X射线衍射和扫描电镜测定样品的显微形貌.结合已经报道的釉砂和玻砂的化学成分,探讨了釉砂、玻砂的现代科技鉴定方法以及对古玻璃研究的重要意义.同时,还讨论了中国釉砂与古埃及釉砂的成分差异,论证了中国古代釉砂的自主生产特征.

Judd-Ofelt intensity parameters of Er3+ doped mixed alkali aluminophosphate glasses

Lithium sodium mixed alkali aluminophosphate glasses of the composition xNa(2)O-(15-x)Li2O-4B(2)O(3)-11Al(2)O(3)-5BaO-65P(2)O(5) (where x=0, 3.75, 7.5, 11.25 and 15 mol%) containing 0.5 mol% Er2O3 were prepared by melt quenching. The absorption spectra of Er3+ were studied from the experimental oscillator strengths and the Judd-Ofelt intensity parameters were obtained. The variations of Judd-Ofelt intensity parameters (Omega(2), Omega(4) and Omega(6)), experimental oscillator strengths of certain excited states of Er3+ and hypersensitive band positions with different mixed alkali content have been discussed in detail. It was found that there were similar effects of mixed alkali on both Judd-Ofelt intensity parameter 02 and the experimental oscillator strength of the hypersensitive transition, I-4(15/2) -> H-2(11/2). No shifts in the peak wavelength of the studied transitions were found in different glasses. (c) 2006 Elsevier B.V. All rights reserved.

The spectroscopic properties of Er3(+)-doped TeO2-Nb2O5 glasses with high mechanical strength performance

(100 - x)TeO2 - xNb(2)O(5) (x=5-20) mobic tellurite glasses doped with 0.5 mol.% Er2O3 were synthesized, and their thermal, mechanical, and spectroscopic properties were measured and compared to the properties of the typical 75TeO(2)-20ZnO-5Na(2)O (TZN) tellurite glass. The refractive index (n(d)), density (p), and glass transition temperature (T-g) of bulk glasses increase with the Nb2O5 content. The Vickers microhardness (H-v) of bulk glass in niobic tellurite glasses also increases with the Nb2O5 content. The values (2.5-3.2 GPa) of H, in the niobic tellurite glasses are 47-88% larger than that (1.7 GPa) in TZN glass. The effect of Nb2O5 content on absorption spectra, the Judd-Ofelt parameters Omega(t) (t = 2, 4, 6), fluorescence spectra and the lifetimes of Er3+ :I-13/2 level were also investigated, and the stimulated emission crosssection was calculated from McCumber theory. With increasing Nb2O5 content in the glass composition, the Omega(t) (t = 2, 4, 6) parameters, fluorescence full width at half maximum (FWHM) Of I-13/2 of Er3+ increase, while the I-4(13/2) lifetimes of Er3+ decreases. Compared with TZN glass, the gain bandwidth properties of Er3+-doped TeO2-Nb2O5 glass is much larger than in tellurite glass based TeO2-ZnO-Na2O system, bismush-based glass, germanate, and silicate glasses, which indicates that TeO2-Nb2O5 glasses are better choice as a practical available host material for broadband Er3+-doped amplifier. (c) 2005 Elsevier B.V. All rights reserved.

表面处理对蓝宝石衬底的影响

蓝宝石衬底是目前最为普遍的一种衬底材料，是生长GaN、Zno材料最常用的衬底。本文用光学显微镜、原子力显微镜(AFM)和高分辨X射线双晶衍射对蓝宝石衬底进行了分析测试，系统研究了经过机械抛光、化学机械抛光、化学腐蚀等表面处理对蓝宝石衬底表面性能的影响。结果表明经过化学机械抛光随后再经腐蚀后的蓝宝石衬底的表面性能最好。