中国武汉上空钠层的首次激光雷达观测

介绍中国科学院武汉物理研究所最近研制成功的钠层共振荧光激光雷达,并利用此雷达在武汉地区对钠层进行观测与研究的初步结果。     

几种地物反射光的偏振特性

偏振测量具有很多普通的光强度测量不具备的优点,是研究地表、大气,探索太空的良好辅助手段。为了获得可见一红外偏振光谱,从而考察利用偏振遥感识别目标的可行性,采用求取斯托克斯参量的方法,分别对草地、黄色环氧板、沥青楼顶、绿帆布、水泥路面及铁板六个样品做了反射光偏振特性测量,并对它们的偏振光谱进行了详细比较,分析了其形成原因。结果表明偏振特性与目标的性质、测量波长、观测角度均有很大关系,偏振测量在遥感和目标识别方面具有重要的意义。     

(S)-异丝氨酸的合成

（S）－异丝氨酸是一种具有生物活性的β－氨基酸和重要的医药中间体。本文重点介绍了以手性化合物为原料合成（S）－异丝氨酸的路线。并对（S）－异丝氨酸的不对称合成路线进行了系统阐述。     

三元Mg2-xRExNi（where RE=La，Ce，Pr，Nd，Y）合金的制备研究

利用两步法制备了一系列三元Mg2-xNdxNi(z=0．05，0．1，0．2，0．3)合金和Mg1.95RE0.05Ni(where RE=La，Ce，Pr，Nd，Y)合金。XRD分析证实，当x为0．05和0．1时，制得的三元Mg2-xNdxNi和Mg2Ni单相合金。x为0．2和0．3时，制得多相合金，合金的相组成为Mg2Ni，NdNi，NdMgNi4。一系列Mg1.95RE0.05Ni合金也均为Mg2Ni单相合金。根据硅内标法计算出的Mg2Ni相的晶格参数的变化，推测认为，添加的稀土元素会引起：Mg2Ni相发生晶格畸变，为保持结构的稳定，Mg2Ni相的晶格可能沿a轴和c轴以近似相同的比例变形或膨胀，故计算出的△a，△c变化较大，而△(c／a)变化很小。由两步法制备的Mg2Ni合金和三元Mg1.95RE0.05Ni(where RE=La，ce，Pr，Nd，Y)合金，球磨时有Mg2Ni相的分解为Mg和Ni的反应发生，而三组元Mg1.95RE0.05Ni合金除此外，还存在替换或固溶的稀土元素RE从Mg2Ni晶格结构中离解或脱溶，且其离解或脱溶要早于Mg2Ni相的分解反应而发生。样品中存在的并非单质的RE，而是相应的稀土氧化物。     

Angular Momentum in the Formation of Disk Galaxies

Within the current framework of disk galaxy formation, we discuss the resulted surface-density profiles according to the theoretical angular momentum distributions (AMDs) presented by Bullock et al. [Astrophys. J.555 (2001) 240(B01)] for the ACDM cosmology in both spherical and cylindric coordinates. It is found that the derived surface density distribution of a disk in the outer region is in general similar to an exponential disk for both the theoretical AMDs. In the central region, the results from both the theoretical AMDs are inconsistent with observations whatever the disk bar-instability is taken into account or not. The cylindric form of the theoretical AMD leads to the bar-instability more easily for a give galaxy than that for spherical AMD, which could result in a more massive bulge. After comparing the model predictions with our Milky Way galaxy, we find that the theoretical AMDs predict larger mass fractions of baryons with low angular momentum than the observed ones, which would lead to the disk sizes to be smaller. Two possible processes which could solve the angular momentum problem are discussed.     

Realization and Comparison of Several Regression Algorithms for Electron Energy Spectrum Reconstruction

To determine the electron energy spectra for medical accelerator effectively, we investigate a nonlinear programming model with several nonlinear regression algorithms, including Levenberg-Marquardt, Quasi-Newton, Gradient, Conjugate Gradient, Newton, Principal-Axis and NMinimize algorithms. The local relaxation-bound method is also developed to increase the calculation accuracy. The testing results demonstrate that the above methods could reconstruct the electron energy spectra effectively. Especially, further with the local relaxationbound method the Levenberg Marquardt, Newton and NMinimize algorithms could precisely obtain both the electron energy spectra and the photon contamination. Further study shows that ignoring about 4% photon contamination would increase error greatly, and it also inaccurately makes the electron energy spectra ‘ddrift＇ to the low energy.     

410一2200nm角度调谐BBO参量振荡器

介绍了以Nd:YAG激光器的三倍频光作泵浦源，BBO作非线性光学晶体，在410一2200nm波段可连续调谐的光参量振荡器（OPO）的工作原理和实验装置，测定了其调谐曲线的输出能量，并对实验结果做了分析。     

多项选择随机化调查的多样本模型——敏感性问题调查方法(Ⅲ)

敏感性问题调查中常会碰到问题回答为多项选择的情况 ,本文介绍多样本调查模型 .     

新型不对称镍酞菁的合成、表征及光电性质

通过改进传统的酞菁合成方法, 得到了一种新的不对称酞菁2-(4-异丙基苯氧基)-9(10),16(17), 23(24)-三(4-叔丁基苯氧基)酞菁镍(简称NiPc2), 并通过质谱、红外光谱及紫外-可见-近红外光谱对其进行了表征, 分析了其可能的形成机理以及循环伏安性质. 这种新的不对称酞菁在近红外光区有明显的吸收峰, 并且其固体紫外-可见光谱的Q带发生红移, 说明形成了J-聚集体.