原子荧光光谱仪的便携化设计

针对重金属污染现场快速检测领域的发展需求,成功开发首台便携式原子荧光光谱仪。实现了高度集成低功耗进样系统、微型低功耗原子化系统、数字化对光技术、微型光电检测系统以及无线通讯技术等十余项关键技术的重大突破。整机功率仅为12 W,重量仅为10kg,锂电池供电状态下工作时间不小于8h,具备与实验室常规原子荧光光谱仪相同的性能指标,可直接用于砷、汞、铅、镉等重金属的野外现场快速检测。     

X射线荧光光谱法测定陶瓷、色料和釉等物料中主量及次量元素

采用熔融片制样用X射线荧光光谱法对陶瓷、色料和釉物料中Na,Mg,Al,Si,P,S,K,Ca,Ti,Mn,Fe,Ba,Zr,Zn,Hf 15种元素进行了测定,用理论α系数校正基体效应。方法简便、快速、分析结果的准确度完全能满足上述物料分析的要求。还用纯化学试剂和标准样品按一定比例混合制备标准样品,弥补了色料和釉缺少标准或没有标样的困难。又对Zr和Hf元素分析线进行了选择,用ZrLα和HfLβ1作为分析线,而不采用ZrKα,不仅使制备的熔片达到ZrLα线的饱和厚度,使分析结果的准确度和重现性好,而且还消除了ZrKα的谱线对HfLβ1分析线的干扰。     

原子荧光光谱仪的便携化设计

针对重金属污染现场快速检测领域的发展需求,成功开发首台便携式原子荧光光谱仪。实现了高度集成低功耗进样系统、微型低功耗原子化系统、数字化对光技术、微型光电检测系统以及无线通讯技术等十余项关键技术的重大突破。整机功率仅为12 W,重量仅为10kg,锂电池供电状态下工作时间不小于8h,具备与实验室常规原子荧光光谱仪相同的性能指标,可直接用于砷、汞、铅、镉等重金属的野外现场快速检测。     

万州近水平地层区堆积层滑坡成因与变形破坏特征

近水平地层区堆积层滑坡作为一类典型的滑坡,有其特殊的成因与变形破坏特征。文章在研究万州近水平地层区堆积层滑坡的基础上,详细分析了其物质来源、结构成因、形成模式以及变形破坏特征。通过总结万州堆积层滑坡的滑体和滑床特征,得出了近水平地区堆积层滑坡的物质来源和结构成因为:崩塌堆积为主,冲、洪积为辅;形成模式为:后部陡壁形成,滑床形成,滑体底部物质形成,滑体土石混合体形成,滑体表层物质形成,滑动解体等6个阶段。变形破坏特征为:滑动多沿堆积层和基岩接触面滑动,同时也会沿软弱夹层发生滑动;滑体存在多层剪切带,并在不同位置的剪切带其变形速率和累计变形量差别较大,滑体存在着差异变形,对此文章结合实例进行了分析。     

Annealing of natural metamict zircons. I low degree of radiation damage

In-situ time dependent high temperature X-ray powder diffraction was used to investigate the ordering process occurring during annealing of natural zircons with a low degree of radiation damage. It was possible to distinguish two stages of this process. Firstly, the diffusion of defects induced by α-particles, this stage contributes only to a certain degree of relaxation in the unit cell. In the second stage there is some degree of recrystallization. A hkl-dependence in the variation of the integrated intensity is observed and the increase in the volume of crystalline zircon is therefore related to a process of migration of dislocations.     

Enantioselective conjugate addition of diethylzinc to cyclic enones catalyzed by chiral copper complexes containing a new phosphorus ligand with an H8-binaphthoxy moiety

A new chiral phosphorus amidite ligand with an H₈-binaphthoxy moiety was synthesized and applied to the copper-catalyzed asymmetric conjugate addition of diethylzinc to cyclic enones with high enantioselectivity. The results gave support to the generality of the advantage of the sterically more demanding H₈-binaphthyl backbone in biaryl chiral ligands.     

高速远程滑坡-碎屑流运动机理研究发展现状与展望

高速远程滑坡-碎屑流具有极高的运动速度和超远距离的位移,往往能够引发灾难性事故,造成严重的生命财产损失,因此,它的运动机理,即高速远程效应机理一直是国内外学者研究的热点。目前国外主要存在四种观点:空气润滑模型、颗粒流模型、能量传递模型和底部超孔隙水压力模型。但是,由于高速远程滑坡-碎屑流自身的复杂性,到目前为止,研究还没有取得公认的成果。 中国是高速远程滑坡-碎屑流的频发区,因其研究才刚刚起步,研究成果还处于定性阶段。本文在查阅大量文献的基础上,从理论和技术两方面分别阐述了国内外高速远程滑坡-碎屑流运动机理研究的发展现状,对目前纵多的理论和模型进行了归纳与总结,点评了目前研究的难点,并在此基础上提出了今后的研究重点。本文是国内外首次对该领域的研究进行系统的归纳和总结,对今后类似的研究具较高的参考价值。     

Messenger sneutrinos as cold dark matter

In models where supersymmetry breaking is communicated into the visible sector via gauge interactions the lightest supersymmetric particle is typically the gravitino which is too light to account for cold dark matter. We point out that the lightest messenger sneutrinos with mass in the range of one to three TeV may serve as cold dark matter over most of the parameter space due to one-loop electroweak radiative corrections. However, in the minimal model this mass range has been excluded by the direct dark matter searches. We propose a solution to this problem by introducing terms that explicitly violate the messenger number. This results in low detection rate for both direct and indirect searches and allows messenger sneutrinos to be a valid dark matter candidate in a wide region of SUSY parameter space.     

Low temperature far-infrared complete reflectivity spectra of single crystal Ba hexaferrite

Far-infrared reflectivity measurements on single crystal barium hexaferrite are presented for E∥C and E⊥LC at room and liquid nitrogen temperatures. The experimental results were numerically analysed using two separate methods—Kramers-Krönig analysis and a fitting procedure based on a four parameter method. All 13 active modes for E∥C predicted by group theoretical analysis were observed. The infrared (IR) transversal and longitudinal phonon frequencies and damping factors were calculated for each oscillator.