Diurnal thermal cycling effects on microwave signatures of thin seaice

To investigate effects of diurnal thermal cycles on C-band polarimetric backscatter and millimeter-wave emission from sea ice, the authors carried out a winter experiment at the outdoor geophysical research facility (GRF) in the cold regions research and engineering laboratory (CRREL), the ice sheet grew from open sea water to a thickness of 10 cm in 2.5 days, during which they took polarimetric backscatter data with a C-band scatterometer, interlaced with brightness temperature measurements at 90 GHz in conjunction with meteorological and sea ice characterizations. The initial ice growth in the late morning was slow due to high insolation. As the air temperature dropped during the night, the growth rate increased significantly. Air temperature changed drastically from about -12 to -36°C between day and night, the diurnal thermal cycle repeated itself the next day and the growth rate varied in the same manner. Ice temperature profiles clearly show the diurnal response in the ice sheet with a lag of 2.5 h behind the time of the maximum short-wave incident solar radiation. The diurnal cycles are also evident in the millimeter-wave brightness temperature data, measured sea ice backscatter revealed substantial diurnal variations up to 6 dB with repeatable cycles in synchronization with the temperature cycles and the brightness temperature modulations, the diurnal cycles in backscatter indicate that the dominant scattering mechanism related to thermodynamic processes in sea ice is reversible, a diurnal backscatter model based on sea ice electrodynamics and thermodynamics explains the observed diurnal signature. This work shows that diurnal effects are important for inversion algorithms to retrieve sea ice geophysical parameters from remote sensing data acquired with a satellite synthetic aperture radar (SAR) or scatterometer on Sun-synchronous orbits     

半导体激光器列阵有源区电场随电流变化的定点测量

采用连续波电光检测法，对ＧａＡｓ／ＧａＡｌＡｓ双异质结激光器列阵有源区进行定点测量，实验结果反映了发光区内及发光区外电场随电流变化的不同规律。文中对实验结果给出了合理解释。     

具有PDEB LB膜的声表面波湿度传感器

介绍一种新型聚炔离子导体湿敏材料－聚对二炔苯的Ｌａｎｇｍｕｉｒ－Ｂｏｌｄｇｅｔｔ成膜原理与制备，淀积有１０层ＰＤＥＢ ＬＢ膜层的声表面波延迟线型湿度传感器的特性。由于ＬＢ成膜技术拉制的膜可以在分子水平上进行定量控制，保证了膜的均匀性和一致性。     

硼酸铝钕(NAB)晶体光学均匀性的测量

NAB晶体是一种综合性能较好的新型激光工作物质,有希望做成高效的小型固体激光器。本文介绍一种测量这种晶体光学均匀性的方法。 一般都采用在干涉仪上观测干涉图样来判定激光棒的光学均匀性。NAB晶体的吸收光谱曲线显示出其在可见光光谱区内有多个吸收峰。我们注意到:通常用做激光干涉仪光源的He-Ne激光器发射的632.8nm谱线正位于NAB晶体的一个吸收峰,并用输出约为45mW     

N-[(2,2–propinyldiferrocenyl)methinyl]benzoyl hydrazone and its bivalent transition metal complexes

Transition Metal Chemistry -     

How to Build Robust Shared Control Systems

Previous researchers have designed shared control schemes with a view to minimising the likelihood that participants will conspire to perform an unauthorised act. But, human nature being what it is, systems inevitably fail; so shared control schemes should also be designed so that the police can identify conspirators after the fact. This requirement leads us to search for schemes with sparse access structures. We show how this can be done using ideas from coding theory. In particular, secret sharing schemes based on geometric codes whose dual [n,k,d] codes have d and n as their only nonzero weights are suitable. We determine their access structures and analyse their properties. We have found almost all of them, and established some relations among codes, designs and secret-sharing schemes.     

实现多层混合刻蚀薄膜大面积均匀的方法浅探

采用多层光刻工艺结合氩离子铣的混合刻蚀方法，刻蚀高Ｔｃ超导ＹＢａＣｕＯ／ＺｒＯ２（１００）薄膜图形，取得了较好的结果。在进行氩离子镜的工艺步骤中，使用普通氩离子铣设备（离子束斑极不均匀），但采取了一定的措施─－使被刻样品在刻蚀台座上可移动，模糊地实现了薄膜的相对＂大面积＂（直径φ≥２０ｍｍ）均匀刻蚀─－可同时刻蚀２～３片６ｍｍ×１０ｍｍ薄膜，并且被刻蚀部分表面起伏约在１０ｎｍ左右。图形样品的最小线条达２μｍ，其Ｔｃ、Ｊｃ人与刻蚀前薄膜的Ｔｃ、Ｊｃ相当，即：ＴＣ为８５～９０Ｋ，Ｊｃ～１０６Ａ／ｃｍ２（在７７Ｋ下）。     

A Construction of Optimal Constant Composition Codes

In this paper, a construction of optimal constant composition codes is developed, and used to derive some series of new optimal constant composition codes meeting the upper bound given by [13].     

Electron attenuation lengths in fullerene and fullerides

Using X-ray photoemission measurements, we have determined the attenuation length of C 1s photoelectrons in C₆₀ film to be 21.5 Å with the incident photon energy of Mg Kα radiation. The inelastic mean free path calculated with the TPP-2M algorithm coincides fairly well with the experimentally determined attenuation length, indicating the validity of the algorithm to fullerene and fullerides. The inelastic mean free paths for some fullerides, i.e. K₃C₆₀, K₆C₆₀, Ba₄C₆₀, Sm_2.75C₆₀ and Sm₆C₆₀ are calculated to help the quantitative analyses of the photoemission spectra for these compounds.     

Windows CE.Net嵌入式操作系统本地化研究及实现

本文对嵌入式Windows CE.Net操作系统的主要体系结构进行剖析.研究设计出了维吾尔文本地化环境,利用资源编译器编译和反编译功能,构建了基于Windows CE.Net平台的维吾尔文图形用户界面资源库,实现Windows CE.Net的界面维文化和基于Windows CE.Net的应用程序的维文支持;开发了输入法程序,实现Windows CE.Net的维吾尔文字键盘输入和软键盘输入;通过编制维吾尔文字库,为Windows CE.Net平台下维吾尔文字的显示、打印提供了基础.