类锂硅离子软X射线激光研究

在激光等离子体典型参数条件下，利用碰撞－辐模型计算了类锂硅离子５ｆ－３ｄ和４ｆ－３ｄ跃的粒子数反转比率和激光增益系数。讨论了不同热带条件和不同冷却速度下，激光增益系统数的变化。计算结果表明，高功率，短脉冲激光生产的高温等离子体在快速冷却条件下能产生软Ｘ射的线激光增益。     

4f轨道的成键性质

本文介绍了目前国内外关于镧系配合物４ｆ轨道成键行为研究的现状与进展,对其理论和研究方法进行了系统的总结,归纳了４ｆ轨道的成键规律。     

稀土金属低温电阻与s—f交换作用

本文考虑４ｆ壳层未填满的稀土金属的ｓ－ｆ交换作用，利用Ｆｅｙｎｍａｎ图方法，讨论了传统的电子－声子耦合与ｓ－ｆ交换作用的影响，并定量地估计了ｓ－ｆ交换作用与电子－电子交换作用对声子电阻的影响。     

稀土离子光谱探针技术研究——稀土离子与环境配体耦合边带的观测

用纳秒脉冲激光作为激发光源，在激发谱中观察到了Ｔｂ＾３＋的４ｆ－４ｆ电子跃迁与ＯＨ，ＯＤ键伸缩振动的耦合边带。实验上采用了时间分辨技术及扣除背影的计算机数据处理方法，有效地克服 杂质荧光和拉曼散射的背景干扰，获得了清晰的Ｔｂ＾３＋振动谱带。     

4f~25g~1组态对Nd~(3 )∶YVO_4晶体光谱的影响

从ＪｕｄｄＯｆｅｌｔ理论和群链方案出发，在考虑了ＹＶＯ４晶体中Ｎｄ３＋的４ｆ２５ｇ１组态或７阶奇晶场的影响下，理论上导出了晶场作用下电偶极跃迁矩阵元公式，据此计算Ｎｄ３＋∶ＹＶＯ４有关光谱跃迁相对强度和偏振性质．与只考虑４ｆ２５ｄ１组态的影响相比，４Ｆ３／２→４Ｉ１１／２跃迁谱线相对强度的ＲＭＳ值由００８降为００５，计算结果与实验更加一致     

Ba1—x—yEuxGdyMgF4＋y复合氟化物中Eu^2＋离子的f—f跃迁线谱发射

报道了Ｇｄ＾３＋与Ｅｕ＾２＋共掺杂的钡镁复合氟化物在室温下的发射光谱中，不仅存在Ｅｕ＾２＋的带状发射，而且还出现了Ｅｕ＾２＋的４ｆ（＾６Ｐ７／２）－４ｆ（＾８Ｓ７／２）线谱发射，在该体系中，由于Ｇｄ＾３＋掺入后，诱导出一另一种Ｅｕ＾２＋的线谱发射中心，两种Ｅｕ＾２＋发射中心的激发光谱明显不同，ｆ－ｆ跃迁线谱发射的强度与Ｇｄ＾３＋及Ｅｕ＾２＋的浓度密切相关。     

火焰原子吸收法间接测定植物中的硫

根据植物中的硫消化后，消化液中的ＳＯ＾２－４与ＢａＣｒＯ４悬浊液反应释放出ＣｆＯ＾２－４，用火焰原子吸收法间接测定ＳＯ＾２－４。本文研究了影响试样消化液中ＳＯ＾２－４定量测定的各种条件，通过加入一定的量的钙，解决大量共存ＰＯ＾３－４的干扰。与电感耦合等离子体发射光谱法进行了结果对照，基本一致。     

CexY3—xAl5O12中Ce^3＋的4f多重态耦合对其磁矩和磁光性能的影响

计算了ＣｅｘＹ３－ｘＡｌ５Ｏ２晶体中Ｃｅ＾３＋由晶场导致的４ｆ欧重态之间的耦合对Ｃｅ＾３＋离子基态磁矩和磁光Ｆａｒａｄａｙ旋转的影响及其温度特性。结果表明，Ｃｅ＾３＋４ｆ＾２Ｆ７／２和＾２Ｆ５／２多重态的耦合，使Ｃｅ＾３＋的基态磁和左在温度３００Ｋ和２０Ｋ时分别     

SrAl2O4：Eu^2＋,Dy^3＋荧光材料的发光性质

我们在本文中制作了五种不同ＳｒＡｌ２Ｏ４：Ｅｕ＾２＋和Ｄｙ＾３＋的样品。样品分别是ＳｒＡｌ２Ｏ４基质的α相和β相的粉末和片状样品,以及单晶样品。我们对所有样品进行了形貌的ＳＥＭ研究。我们还对α相和β相粉末样品及片状样品以及α相单晶样品的荧光发射谱进行了测量。它们的荧光发射的中心波长为５２０ｎｍ,对应于ＳｒＡｌ２Ｏ４基质中的Ｅｕ＾２＋的４ｆ＾６５ｄ＾１的＾２ｅｇ激发态到４ｆ＾７的＾８Ｓ７／２的跃迁发     

4f2g5^1组态对Nd^3＋：YVO4晶体光谱的影响

从Ｊｕｄｄ－Ｏｆｅｌｔ理论和群链方案出发，在考虑了ＹＶＯ４晶体中Ｎｄ＾３＋的４ｆ＾２５ｇ＾１组态或７阶奇晶场的影响下，理论上导出了晶场作用下电偶极跃迁矩阵元公式，据计算Ｎｄ＾３＋：ＹＶＯ４有关光谱跃迁相对强度和偏振性质。     

表面电荷密度法的应用研究

本文介绍了一种边界积分方程法——表面电荷密度法。它可用于处理轴对称电场和三维电场,特别是包含介质和开放边界的系统;还可用来精确确定各种形状电极间的电容。本文对应用此法所遇到的各种奇异性问题进行了讨论,在理论推导的基础上,编制了通用程序,它可处理包含圆形、直线形电极和介质的轴对称系统,可处理矩形平面电极的三维场。利用这个程序,对尖端发射体外的电位分布及快速变像管中一种常用的聚焦系统的空间电位分布进行了计算,与差分法作了比较,还计算了考虑介质边界后的影响;计算了单球体的空间电位分布,并与解析值进行了比较,计算了几种模型的电容,并与解析值和极限值进行了比较。     

具有高光学质量共焦和非共焦自滤波非稳腔的激光束

具有腔内滤光器的共焦和非共焦负支非稳腔应用于高增益、短脉冲紫外予电离氯化氙激光器,在上述两种腔结构,研究了各种空间滤光器条件下的近场和远场辐射特性,获得了有规则强度空间剖面的高亮度激光束,特别是非共焦机构,最大束亮度达1.3×10~(14)瓦·厘米平方·立体角,并且观察到,这种腔结构对于失调的低灵敏度.     

Holography in partially coherent light

A Michelson interferometer has been used to obtain good holographic carrierfringes of the order of 200 to 300 fringes/ mm over an area of 1 cm × 1.5 cm with a Hg-are source and extended aperture with and without filter. The fringes have been used to record holograms. The image reconstruction has been done with light from the Hg-arc without the use of any filter. Experimental results for a continuous-tone object have been presented. The advantages and disadvantages and some of the potential applications of this technique have been mentioned.     

Coherent and diffuse X-ray scattering from a multicomponent superlattice with quantum dots

GaAs-AlAs superlattices with InAs quantum dots grown by molecular beam epitaxy have been studied by high-resolution X-ray diffractometry. It has been experimentally revealed that the maxima of the superstructural diffuse scattering from the quantum dots do not coincide with the angular positions of the coherent superstructural satellites. A statistical theory of diffraction on the superlattice taking into account the spatial correlation of the quantum dots has been developed to explain this effect. It has been shown within this theory that the peak positions of the diffuse component can differ from the maxima of the coherent scattering. X-ray scattering by the multicomponent superlattice have been numerically simulated and the calculation results have been compared with the experimental data.     

Dielectric and calorimetric investigations of KNO3 in pores of nanoporous silica matrices MCM-41

The temperature dependences of the linear dielectric permittivity, the third harmonic amplitude, and the heat capacity of nanoporous silica matrices MCM-41 with cellular channels (3.7 and 2.6 nm in diameter) filled with KNO₃ have been investigated in comparison with those obtained for bulk potassium nitrate. Measurements have been performed during heating and cooling in the range from room temperature to 463 K. Anomalies corresponding to structural phase transitions have been observed. A significant broadening of the temperature region of the existence of the ferroelectric phase III of potassium nitrate upon cooling has been revealed. This broadening increases with a decrease in the size of pores. It has been shown that, in the nanocomposites with potassium nitrate, the ferroelectric phase can also be formed during heating. The efficiency of observation of the third harmonic generation for studying nanocomposites with the ferroelectric phase has been demonstrated.     

X-ray photoelectron studies of pure and oxidised ytterbium and lutetium

X-ray photoelectron spectra of pure and deliberately oxidised ytterbium and lutetium have been investigated with a high-vacuum instrument (VG-ESCA3), using both aluminium and magnesium Kα radiation. Core-level binding energies are measured accurately with respect to the Fermi level of the pure metal and discrepancies have been found between the present and previously published data. Precise information regarding the location of 4f-levels with respect to the Fermi level has been obtained. The splitting of the 4f levels has been observed and yields some interesting information. The present results have been compared with those available from theoretical and other experimental reports.     

Study of the interaction of a palladium nanocontact with a hydrogen molecule

The interaction of a palladium nanocontact with a hydrogen molecule has been studied using molecular static method. The influence of impurity on the atomic structure and mechanical properties of the palladium nanocontact has been demonstrated. The characteristic interatomic distance has been determined in this contact. It has been found that the hydrogen molecule dissociates by interaction with nanocontact atoms.     

Influence of the surface curvature of carbon nanotubes on their conductivity in the dirac approximation

A method of surface curvature of carbon nanotubes has been proposed for quantitative estimation of the longitudinal conductivity of nanotubes. A dispersion relation for the electron spectrum of single-walled carbon nanotubes has been obtained analytically. The change in the zone structure of nanotubes of various types and diameters caused by taking into account the surface curvature has been analyzed. The temperature dependence of the longitudinal component of conductivity with allowance for the surface curvature for a series of nanotubes has been calculated. The comparison with the conductivity of a plane graphene has been performed. It has been shown that, in zig-zag tubes, the correction of the conductivity for the surface curvature decreases with an increase in temperature as well as with an increase in the radius of curvature.     

Evaporation waves in a metastable single-component liquid

In this paper, evaporation waves appearing at rapid depressurization of a vessel filled with liquid Freon R11 have been investigated experimentally. Regimes with a high-speed evaporation front have been revealed. It has been shown that the disintegration of a metastable liquid takes place in the form of a surface evaporation wave with a cellular structure of the front and anomalously high values of the coefficient of heat transfer from the liquid. The dependence of the evaporation front velocity on the initial temperature of the liquid has been obtained. A critical temperature value below which evaporation waves are not observed has been determined. Visualization of the evaporation front structure and dynamics with the use of a high-speed video camera has been performed. It has been found that the evaporation front motion has a pulsatory character. A method to calculate the surface evaporation wave with a quasi-plane interphase boundary has been developed. It is based on a model of nonequilibrium evaporation of the liquid and experimentally measured coefficients of the heat transfer from the liquid.     

Features of magnetic and magnetoelectric properties of rare-earth multiferroic PrFe3(BO3)4 with the singlet ground state

The features of magnetization of rare-earth multiferroic PrFe₃(BO₃)₄ with the singlet ground state have been investigated theoretically. The magnetic anisotropy of the crystal has been studied. The temperature dependences of anisotropy constants have been calculated. The phase H-T diagram has been constructed. The dependences of the behavior of magnetization vectors of magnetic sublattices on the external magnetic field have been obtained. The magnetoelectric effect has been investigated, and the dependences of polarization on the temperature and field have been found for its various orientations. The theoretical data have been compared with the experimental data and their good agreement has been established.