High-accuracy same-beam VLBI observations using Shanghai and Urumqi telescopes

The same-beam VLBI observations of Rstar and Vstar, which were two small satellites of Japanese lunar mission, SELENE, were successfully performed by using Shanghai and Urumqi 25-m telescopes. When the separation angle between Rstar and Vstar was less than 0.1 deg, the differential phase delay of the X-band signals between Rstar and Vstar on Shanghai-Urumqi baseline was obtained with a very small error of 0.15 mm rms, which was reduced by 1-2 order compared with the former VLBI results. When the separation angle was less than 0.56 deg, the differential phase delay of the S-band signals was also obtained with a very small error of several mm rms. The orbit determination for Rstar and Vstar was performed, and the accuracy was improved to a level of several meters by using VLBI and Doppler data. The high-accuracy same-beam differential VLBI technique is very useful in orbit determination for a spacecraft, and will be used in orbit determination for Mars missions of China Yinghuo-1 and Russia Phobos-grunt.

Cyanex302及CA-12萃取稀土动力学的研究

随着萃取技术的不断发展，人们日益要求更加深入的了解萃取过程的机制及其动力学特性。以便有效地控制和强化萃取过程，提高萃取效率，或者利用萃取动力学的差异来实现某些分离嘴过程。尽管许多萃取过程进行得很快，但是人们也发现不少的金属鳌合物萃取体系，其萃取过程相当缓慢。因而这类体系的萃取机制和萃取动力学问题已日益引人注目。除此而外，在设计，放大或改进萃取设备时，研究和掌握有关萃取过程的动力学规律也有十分重要意义。在本文中主要对稀土萃取动力学进行了研究，得到主要结果如下：1．研究了硫代有机磷酸Cyan.ex302萃取饵的动力学。通过测定各种萃取条件对萃取速率的影响，获得了萃取速率方程，并讨论了萃取的控制过程。实验发现萃取剂中的杂质对萃取具有较大的加速作用，这对工业生产具有一定的实际意义。2.用两相滴定法测定了两种新合成的J梭酸萃取剂CA-12和CA-100的某些重要的物理常数。这将有助于深入研究它们的萃取性质及机理。3．用层流恒界面池研究了CA-12萃取La, Gd,Er, Yb和Y的动力学。考察了各种因素对萃取速率的影响，获得了它们的萃取速率方程，实验发现了它们的萃取控速步骤并推测了其萃取机理。4．研究了HEHEHP对CA-12萃取Yb和Y的动力学的影响。实验发现在CA一12中加入少量的HEHEHP后，萃取活化能显著降低，萃取速率明显加快。由于加入HEHEHP后，萃取Yb的活化能的降低要比萃取Y的活化能降低的程度大'，所以使Yb和Y的萃取分离因素加大。5．用两相滴定法研究了HEHEHP萃取铭的机理，CA-12萃取稀土及其相关离子的机理。并计算了它们相应的平衡常数。

Co(salen)作为辅酶B_(12)模型物及化学修饰电极的电化学研究

本论文从合成Co(salen)开始，对Co(salen)在电化学现场合成辅酶B_(12)模型物的工作进行了尝试。进一步地，用Co(salen)制作了两种化学修饰电极，并对它们的性质进行了较为详细的考察。同时还将这两种修饰电极应用于电催化研究工作，得到了较为满意的结果。

Kinetics of dissociative water adsorption on stepped Si(001), on Si(115), Si(113), Si(5,5,12) and Si(112)

We present photoelectron spectroscopic and low energy electron diffraction measurements of water adsorption on flat Si samples of the orientations (001), (115), (113), (5,5,12) and (112) as well as on curved samples covering continuously the ranges (001)-(117) and (113)-(5,5,12)-(112). On all orientations, water adsorption is dissociative (OH and H) and non-destructive. On Si(001) the sticking coefficient S and the saturation coverage Theta(sat) are largest. On Si(001) and for small miscuts in the [110]-azimuth, S is constant nearly up to saturation which proves that the kinetics involves a weakly bound mobile precursor state. For (001)-vicinals with high miscut angles (9-13 degrees), the step structure breaks down, the precursor mobility is affected and the adsorption kinetics changed. On (115), (113), (5,5,12) and (112), the values of S and Theta(sat) are smaller which indicates that not all sites are able to dissociate and bind water. For (113) the shape of the adsorption curves Theta versus exposure shows the existence of two adsorption processes, one with mobile precursor kinetics and one with Langmuir-like kinetics. On (5,5,12), two processes with mobile precursor kinetics are observed which are ascribed to adsorption on different surface regions within the large surface unit cell. From the corresponding values of S and Theta(sat), data for structure models are deduced. (C) 1997 Elsevier Science B.V.

Electron diffraction and photoemission studies of clean and water-covered Si(5,5,12) and Si(112) surfaces

The structure of silicon surfaces in the orientation range (113)-(5,5,12)-(337)-(112) has been investigated using high resolution LEED and photoemission both on a spherical and on flat samples. We find that Si(5,5,12) [5.3 degrees from (113) and 0.7 degrees from (937)] is the only stable orientation between (113) and (111) and confirm the result of Baski et al. [Science 269, 1556 (1995)] that it has a 2 x 1 superstructure with a very large unit cell of 7.68 x 53.5 Angstrom(2). Adsorption measurements of water on Si(5,5,12) yield a mobile precursor kinetics with two kinds of regions saturating at 0.25 and 0.15 ML which are related to adsorption on different sites. Using these results, a modified structure model is proposed. Surfaces between (113) and (5,5,12) separate into facets of these two orientations; between (5,5,12) and (112), they separate into (5,5,12) and (111) facets. (337) facets in this range may be considered as defective (5,5,12) facets.

Long period two-dimensional gratings for 8-12 mu m quantum well infrared photodetectors

By considering all possible high order diffracted waves, the authors investigate the spectral response of two-dimensional gratings for quantum well infrared photodetectors (QWIPs). A new method is proposed that using long period gratings may improve grating quality and reduce the resulting cross talk in grating-coupled QWIPs. A sensitivity analysis indicates that the influence of variation of the grating constant on the coupling efficiency is less sensitive for the long period gratings than for the short ones. A large coupling efficiency has been demonstrated for long period gratings. The calculated wide grating response spectra are in good agreement with the experiment result. (C) 1996 American Institute of Physics.

12路40Gb/s甚短距离并行光传输信号转换器研究

基于OIF-VSR5-01.0规范,分析了12路并行40Gb/s甚短距离(VSR)光传输转换器模块的实现原理.采用top-down分析方法,使用硬件描述语言verilog,在可编程逻辑器件上完成了时钟数据恢复、基于字节对齐方案的帧同步、信道去斜移、比特间差奇偶校验(BIP)等功能模块的程序设计,实现了SFI-5与OIF-VSR5-01.0电信号格式的相互转换,并在Altera的Stratix II GX 系列的高速现场可编程门阵列(FPGA)上对功能模块进行了功能验证和联合仿真.结果表明所设计的各个功能模块满足系统应用要求,为下一步将系统设计转换为专用集成电路(ASIC)奠定了基础.

A High Speed, 12-Channel Parallel, Monolithic Integrated CMOS OEIC Receiver

The design and fabrication of a high speed, 12-channel monolithic integrated CMOS optoelectronic integrated circuit(OEIC) receiver are reported.Each channel of the receiver consists of a photodetector,a transimpedance amplifier,and a post-amplifier.The double photodiode structure speeds up the receiver but hinders responsivity.The adoption of active inductors in the TIA circuit extends the-3dB bandwidth to a higher level.The receiver has been realized in a CSMC 0.6μm standard CMOS process.The measured results show that a single channel of the receiver is able to work at bit rates of 0.8～1.4Gb/s. Altogether, the 12-channel OEIC receiver chip can be operated at 15Gb/s.

截止波长12μm的InAs0.04Sb0.96/GaAs的熔体外延生长及特性研究

用熔体外延(ME)法在半绝缘(100)GaAs衬底上成功生长出了截止波长为12 μm的InAs0.04Sb0.96外延层.傅立叶变换红外(FTIR)透射光谱揭示,InAsSb合金的禁带宽度被强烈变窄.通过分析InAs0.04Sb0.96外延层载流子浓度的温度依存性表明,其室温禁带宽度为0.105 5 eV,与透射光谱测得的数值很好地一致.通过测量12～300 K的吸收光谱,研究了InAs0.04Sb0.96/GaAs的禁带宽度的温度依存性.霍尔测量得出300 K下样品的电子迁移率为4.47×104 cm2/Vs,载流子浓度为8.77×1015 cm-3;77 K下电子迁移率为2.15×104 cm2/Vs,载流子浓度为1.57×1015 cm-3;245 K下的峰值迁移率为4.80×104 cm2/Vs.

Si（5,5,12）-一个大元胞的稳定表面

于2010-11-23批量导入

含杂六角密积结构原子簇Al（12）M的电子结构

于2010-11-23批量导入

柞蚕核型多角体病毒B-ORF6L、ptp、lef-12基因克隆及表达

本研究克隆了柞蚕核型多角体病毒（Antheraea pernyi nucleopolyhedrovirus，ApNPV）基因组pstⅠ-B、pstⅠ-C、pstⅠ-J三个片段，测序分析了pstⅠ-B、pstⅠ-C片段全序列及pstⅠ-J片段一端序列。ApNPV pstⅠ-C片段长6663 bp，包括9个完整ORF及2个不完整ORF；ApNPV pstⅠ-B片段长7406 bp，包括5个完整ORF及2个不完整ORF。ApNPV pstⅠ-J片段末端测定的954 bp序列包括lef-12完整序列及p47和gta部分序列。本研究共鉴定21个ApNPV ORF序列，其中20个属首次报道，占ApNPV已报道基因数的50％。编码ORF同源性分析及克隆片断ORF组成、基因排列顺序分析表明ApNPV与鳞翅目NPV第Ⅰ类群中的OpMNPV、CfMNPV、CfDefNPV、EppoNPV关系较近。 本研究克隆了ApNPV B-ORF6L、ptp-1、ptp-2及lef-12 四个基因，并对这四个基因在柞蚕蛹体内的表达进行了转录分析，结果表明：ApNPV ptp-1、lef-12是早期基因，B-ORF6L、ptp-2是晚期基因。本研究将ApNPV B-ORF6L、ptp-2亚克隆至原核表达载体，并在大肠杆菌中获得高效表达。SDS-PAGE及Western blot分析表明：PTP-2原核表达分子量与预测分子量相符，B-ORF6L融合表达分子量较预测的分子量偏大。以原核表达的B-ORF6L、PTP-2蛋白作为抗原，成功制作了B-ORF6L和PTP-2蛋白兔多克隆抗血清。ApNPV蛋白组分印迹分析表明：B-ORF6L参与包涵体膜及ODV结构组成，是ApNPV结构蛋白；PTP-2不参病毒结构组成。 分子系统发育分析表明，杆状病毒分为4个大的类群，ApNPV属于鳞翅目NPV第Ⅰ类群，与OpMNPV、CfMNPV、CfDefNPV、EppoNPV关系较近，与AcMNPV、RoMNPV、BmNPV关系稍远。