Effects of external fields on a two-dimensional Klein-Gordon particle under pseudo-harmonic oscillator interaction

We study the effects of the perpendicular magnetic and Aharonov-Bohm(AB) flux fields on the energy levels of a two-dimensional(2D) Klein-Gordon(KG) particle subjected to an equal scalar and vector pseudo-harmonic oscillator(PHO).We calculate the exact energy eigenvalues and normalized wave functions in terms of chemical potential parameter,magnetic field strength,AB flux field,and magnetic quantum number by means of the Nikiforov-Uvarov(NU) method.The non-relativistic limit,PHO,and harmonic oscillator solutions in the existence and absence of external fields are also obtained.     

A density-functional theory investigation on desorption of O2 on Sn（111） and its comparison with initial oxidation on the X（111） （X=Si,Ge, Sn,Pb） surfaces

<正>The first-principles calculations are performed to investigate the adsorption of O₂ molecules on an Sn（111） 2×2 surface.The chemisorbed adsorption precursor states for O₂ are identified to be along the parallel and vertical channels, and the surface reconstructions of Sn（lll） induced by oxygen adsorption are studied.Based on this,the adsorption behaviours of O₂ on X（111）（X=Si,Ge,Sn,Pb） surfaces are analysed,and the most stable adsorption channels of O₂ on X（111）（X=Si,Ge,Sn,Pb） are identified.The surface reconstructions and electron distributions along the most stable adsorption channels are discussed and compared.The results show that the O₂ adsorption ability declines gradually and the amount of charge transferred decreases with the enhancement of metallicity.     

Theoretical study of potential energy curves,spectroscopic constants,and radiative lifetimes of low-lying states in an SeO molecule

<正>The low-lying potential energy curves of the SeO molecule are computed by means of an ab initio multireference configuration interaction technique,taking into account relativistic(scalar plus spin-orbit coupling) effects.The spectroscopic constants ofΩstates for X~3∑~-,a~1△,b~1∑~+,A~3Π,A′~3△,and A″~3∑~+ states are obtained,and they are in good accordance with available experimental values.The Franck-Condon factors and transition dipole moments to the ground state are computed,and the natural radiative lifetimes of low-lyingΩstates are theoretically obtained. Comparisons of the natural lifetimes ofΩstates with previous experimental results and those of isovalent TeO molecule are made.     

基于碳纤维复合材料的月基极紫外相机照准架结构设计

为了减少月基极紫外相机的质量并保证相机的二维转动机构在卫星发射、地月变轨及月表着陆过程中受到大量级振动冲击以及月表超大温差环境下能正常工作,设计并研制了基于碳纤维复合材料（CFRP）的照准架结构。首先,设计了基于金属材料和CFRP的不同照准架结构,通过有限元法对不同材料的照准架进行分析对比,证明了CFRP照准架的优越性。温度和力学验证试验表明：基于CFRP的照准架质量小于其它材料的照准架,其刚度和热稳定性能满足极紫外相机环境适应性的要求。     

组合式发光二极管路灯反射器的设计

设计了一组合式路灯反射器,以使发光二极管（LED）路灯在道路照明时产生矩形光斑和均匀照度。在非成像光学基础上,利用复合抛物面的高性能集光作用和机械设计软件的强大作图功能,设计了一款分段组合复合抛物面反射器（CPC）。基于“边缘光线原理”和”裁剪法”,此款反射器能将朗伯型发光的LED光束整形为近似矩形分布,出光效率达96％以上。理论模拟证明：在高度为10m,范围为10m×30m内利用此反射器进行二次配光的LED路灯的照度均匀度达0．5以上。该反射式LED路灯光束整形器结构简单,光学效率高、成本低廉,模拟结果完全达到了目前我国国家道路照明规范要求。     

由多个高斯函数表征的发光二极管光谱模型

利用发光二极管（LED）光色电综合测试系统测量不同颜色不同功率的LED在多个电流下的光谱,提出并构建了由多个高斯函数组成的LED光谱模型,并根据各颜色LED在额定电流下的光谱计算模型中的系数,最后将该模型与已报道的模型进行了对比。研究表明：对于光谱有n（n≥1）个波峰的LED,可用3n个高斯函数形式的模型来表示,大功率红、黄、蓝、绿、白色LED模型与实测光谱之间平均误差分别为3．45％、1．01％、2．33％、4．65％、2．49％,小功率LED的平均误差分别为2．61％、2．65％、3．77％、2．87％、2．48％。与已报道的模型相比,该模型精度高,普适性好。本研究对LED光度色度测量仪器的研制及智能化LED产品的设计具有重要意义。     

钪和钇二价离子跃迁几率和振子强度的理论计算

利用最弱受约束电子势模型理论计算了二价钪离了和二价钇离子的能级间跃迁几率和振子强度的数值．二价钪离子的计算结果与美国国家标准技术研究院（NIST）所给出的可接受值吻合良好二价钇离子的计算结果也与现有的其他理论方法的计算结果十分接近．     

Electron Momentum Distributions for 4a1 Orbitals of CFxCl4-x in Low Momentum Region： a Possible Evidence of Molecular Geometry Distortion

Electron momentum distributions for 4a1 orbitals of serial freon molecules CFaC1, CF2Cl2, and CFCl3 （CFxC14-x, x=1-3） have been reanalyzed due to the severe discrepancies between theory and experiment in low momentum region. The tentative calculations using equilibrium geometries of molecular ions have exhibited a great improvement in agreement with the experimental data, which suggests that the molecular geometry distortion may be responsible for the observed high intensities at p〈0.5 a.u.. Further analyses show that the severe discrepancies at low momentum region mainly arise from the influence of molecular geometry distortion on C-Cl bonding electron density distributions.     

Broadband Vibrational Cooling of Cold Cesium Molecules： Theory and Experiments

The use of a broadband, frequency shaped femtosecond laser on translationally cold cesium molecules has recently demonstrated to be a very efficient method of cooling also the vibrational degree of freedom. A sample of cold molecules, initially distributed over several vibrational levels, has thus been transfered into a single selected vibrational level of the singlet X^1∑g ground electronic state. Our method is based on repeated optical pumping by laser light with a spectrum broad enough to excite all populated vibrational levels but limited in its frequency bandwidth with a spatial light modulator. In such a way we are able to eliminate transitions from the selected level, in which molecules accumulate. In this paper we briefly report the main experimental results and then address, in a detailed way by computer simulations, the perspectives for a ＂complete＂ cooling of the molecules, including also the rotational degree of freedom. Since the pumping process strongly depends on the relative shape of the ground and excited potential curves, ro-vibrational cooling through different excited states is theoretically compared.     

[Co2（H2O）6（bpdc）2]·3.75H2O的原位合成、晶体结构及电化学性质研究

室温下,Co（NO3）2·6H2O与1,10–邻菲罗啉–5,6–二酮（pdon）的水溶液进行原位反应,得到一维链状配合物晶体{[Co2（H2O）6（bpdc）2]·3.75H2O}n（bpdc=2,2＇–联吡啶–3,3＇–二羧酸）.单晶X–射线衍射分析表明：该晶体属于单斜晶系,P21/c空间群,晶胞参数为：a=18.001（4）A,b=11.336（2）,c=18.192（4）A,β=118.88（3）°,V=32501（2）A3,Dcalc=1.578 g·cm^-3.每个钴（Ⅱ）离子与周围2个氮原子和4个氧原子配位,形成扭曲的八面体构型,并通过bpdc连接形成沿b轴无限延伸的手性螺旋链.在整个晶体结构中,这些链以准一维堆积方式排列,相互之间存在广泛的氢键作用.同时,电化学分析表明：在磷酸盐缓冲溶液（pH=7.0）中,该配合物在-0.6～0.6V电压范围内具有电化学活性,电极反应为准可逆的Co（Ⅲ）与Co（Ⅱ）的氧化还原过程.