S4中等参超曲面的谱刻画

本文证明了如果Ｓ⁴中的具常平均曲率ｈ的超曲面Ｍ与其具平均曲率ｈ的等参超曲面Ｍ_０（强）等谱，则Ｍ＝Ｍ_０．     

Vibrational frequencies and structural determination of tetraethynylstannane

The normal mode frequencies and corresponding vibrational assignments of Sn(CCH)₄ are examined theoretically using the 98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of six types of motion predicted by a group theoretical analysis (Sn–C stretch, CC stretch, C–H stretch, CC–H bend, Sn–CC bend, and C–Sn–C bend) utilizing the T_d symmetry of the molecule. A set of uniform scaling factors were derived for each type of motion. Predicted infrared and Raman intensities are reported.     

利用等离子体非线性系数实现超强脉冲的压缩

超短脉冲压缩技术在强场物理研究中有非常重要的作用,但由于强场电离现象在惰性气体自相位调制脉冲压缩技术中限制了脉冲的能量。Tempea等人提出可以采用等离子体非线性系数对脉冲进行压缩,本文在考虑毛细管内表面电离的情况下,讨论能量为10mJ左右,脉宽为50fs的脉冲的压缩问题,发现可以将脉冲压缩至5fs左右。计算表明频谱展宽可以在气体密度很低的情况下进行,这样半可以减小电子对脉冲传输的影响。同时,由于毛细管内表面也处于电及状态,从而使脉冲能量不会受到电离阈值的.限制。     

S~4中等参超曲面的谱刻画

本文证明了如果Ｓ４中的具常平均曲率ｈ的超曲面Ｍ与其具平均曲率ｈ的等参超曲面Ｍ０（强）等谱，则Ｍ＝Ｍ０．     

Complete Ligand-Field Calculation of Energy Spectrum and g Factor of MgO:Ni2+ and Their Pressure Effects

The unified calculation of the whole energy spectrum and g factor of ground state for MgO:Ni²⁺ at normal pressure and their pressure-induced shifts has been carried out on the basis of the theory of pressure-induced shifts and the diagonalization of the complete d⁸ energy matrix in a regular octahedral field. A11 the calculated results are in excellent agreement with a lot of experimental data. For the first time, by using the wavefunctions obtained by diagonalization of the complete energy matrix, the pressure-induced shift-of g factor has satisfactorily been calculated and explained by microscopic theory The contributions to typical levels from various parameters have been calculated. The distinct differences of pressure-induced shifts of various levels are immediately determined by their characteristic dependencies on the parameters of interactions. The pressure-induced shifts of levels have provided important criteria for the correctness of the calcutation and assignment of them.     

微波法合成新型红色长余辉材料Gd2O2S:Eu,Mg,Ti中助熔剂的影响

用微波辐射法合成了红色长余辉材料Gd2O2S:Eu,Mg,Ti,用X射线粉末衍射(XRD)、扫描电镜(SEM)、荧光分光光度计等手段对合成产物进行了分析和表征,并研究了不同助熔剂Li2CO3,Na2CO3,K2CO3,Na3PO4,KH2PO4以及Li2CO3和Na2CO3共同作用对材料的微观形貌及发光性能的影响.结果表明:不同的助熔剂的加入均可得到单相晶体,材料的晶体结构为六方晶系,与Gd2O2S的相同.颗粒分散性较好,晶粒尺寸以及形貌因助熔剂的不同而有所差别.发光性质研究表明:不同助熔剂的加入并没有改变样品发射谱主峰位置(627nm),但对其峰强度产生明显影响,激发光谱中的情况与此相似.研究发现Li2CO3和Na2CO3共同作用可有效延长余辉时间.