非相干空间孤子的自陷行为

用相干密度法研究了一维非相干光束在饱和对数型光折变介质中的自陷行为,发现在传输过程中孤子的形态可具有稳态和周期性振荡的特点,具体取决于入射光束的初始宽度、相干特性和材料的非线性响应;研究了构成非相干光束的相干组份的传播行为,发现各相干组份的强度和光束宽度沿纵向发生周期性变化,峰值位置沿横向发生周期性变化.另外,利用横向相干宽度研究了非相干光束在各种传输状态下相干特性的变化,从而进一步解释了非相干光束在不同传播状态下的演化特性.     

Robinson-Trautman equations and Chandrasekhar's special perturbation of the Schwarzschild metric

A perturbation wave solution of the Robinson-Trautman equations is proved to be a perturbation of the Schwarzschild black hole which describes an outgoing axial gravitational wave and corresponds to a special case of Chandrasekhar's algebraically special perturbation of the Schwarzschild metric.     

超软X射线流气式正比计数管

介绍了一种用于测量183～933eV超软X射线的圆柱形、侧窗式、流气式正比计数管,工作气体是0.11MPa的P-10气体或氦气-丙烷混合气体。计数管内径为φ25mm,直径为φ0.3mm的入射窗是由厚度80～90μgcm~2聚乙烯甲醛制成的。该计数管的特点:(1)薄窗,对软X射线透过率高。(2)流气式,工作寿命长。(3)能量分辨率好。(4)计数率高(1×10~(14)个/s)。(5)可测能区宽(0.183～10keV)。(6)可以方便更换窗膜材料、厚度及窗口直径。近几年来该计数管已经为高强度低能X光源提供较好监测。     

HIPS的γ辐照效应的正电子寿命谱研究

测量了高强度聚苯乙烯（ＨＩＰＳ）的正电子寿命谱随γ辐照剂量的变化，观察到自由体积孔洞的平均半径随辐照剂量的增加而基本不变，且自由体积孔洞的浓度和半径分布宽度随辐照剂量的增加而减小．这一实验结果表明，γ辐照后高强度聚苯乙烯力学性能的改善与自由体积特性的变化相关联．     

高纯金属镨中痕量稀土杂质的电感耦合等离子体原子发射光谱分析及光谱干扰的校正

本文提出了PGS-2型平面光栅光谱仪(色散率0.18纳米,二级光谱)与PlasmaTherm ICP-5000D射频发生器联用,乙醇预去溶方式进样,同时直接测定高纯金属镨中5个痕量稀土杂质元素的方法。并讨论了基体浓度对检出限的影响以及光谱干扰及其校正方法。当样品溶液中镨的浓度为5毫克/毫升时,测定下限分别为镧、钕和钐0.002%,铈0.003%和钇0.0005%。获得了良好的实验结果,其相对标准偏差为1.2-6.2%。     

C60在几种溶剂中紫外吸光度的负热效应

所采用的变温光谱差减方法是将待测试样分成两份 ,一份作为参比试样 ,恒定在某一温度 (参比温度 )下 ,另一份作为待测样品 ,选定另一待观测温度 ,在一定的波长范围内 ,用岛津UV 2 4 0型紫外 可见双光束分光光度计扫描 ,获得紫外吸收温差光谱 (UVSDT)。选择不同的温度差 ,测得温差光谱随温差的变化。观测了C60 分子在乙醇、环己烷、正己烷、异丙醇等几种有机溶剂中吸光度随温度的变化。观测结果发现C60 溶液的吸光度变化存在显著的负温度效应。C60 的UV吸收光谱峰随试样温度升高而降低 ,UV吸收温差光谱 (U VSDT)为负峰 ,UVSDT峰强随温差增大而负向增大。说明C60 的结构对温度有较强的依赖关系。这种依赖关系与π π 电子跃迁类型密切相关。实时现场测量C60 溶液的吸光度随温度变化规律 ,对分离、纯化、分析富勒烯 ,认识C60 特性、研究以溶剂为媒介的化学反应机理 ,以及提高测量的准确度和重现性等 ,均有一定的理论意义和实用价值     

量子位Heisenberg XX开链中边界量子位之间的纠缠

Heisenberg 开链对研究量子态在自旋链上的传递有重要的意义.本文研究了五量子位Heisenberg XX 开链中边界量子位之间的纠缠，在该系统中引入了磁杂质和系统杂质且它们之间满足线性关系时，该系统可以精确求解，此时边界量子位之间存在纠缠.选择合适的杂质参数和磁场参数，该边界纠缠的最大值可达到0.5. 关键词： Heisenberg XX开链 边界纠缠 杂质     

Analytical vectorial structure of Hermite-cosine-Gaussian beam in the far field

Based on the vector angular spectrum representation of electromagnetic beams and the method of stationary phase, the vectorial structure of a Hermite-cosine-Gaussian (HcosG) beam in the far field is derived in analytical form. Energy flux distributions for the TE term, TM term and the whole beam are represented. The vectorial structures of HcosG beams with different Hermite models are depicted. The effects of cosine displacement parameters on the vectorial structure are also demonstrated. The results may provide a flexible approach to manipulate HcosG beams in free space.     

Structural and magnetic properties of pulsed laser deposited SrRuO3/CoFe2O4/La2/3Sr1/3MnO3 magnetic oxide heterostructures on SrTiO3(001) and MgO(001)

We report on the growth of all-oxide SrRuO₃/CoFe₂O₄/La_2/3Sr_1/3MnO₃ and La_2/3Sr_1/3MnO₃/CoFe₂O₄/SrRuO₃ heterostuctures on SrTiO₃(001) and MgO(001) substrates by pulsed laser deposition. Structural analyses by X-ray diffraction and transmission electron microscopy clearly indicate the preservation of epitaxial relations when the La_2/3Sr_1/3MnO₃ layer is grown first, whereas trilayers with SrRuO₃ at the bottom are more disordered. Both the substrate material and the deposition sequence strongly influence the formation of various structural defects such as interfacial dislocations and sub-grain structures, and this is clearly reflected by a reduction of the saturation magnetization in the top electrode. When the substrate material and the deposition sequence are correctly chosen, however, the magnetic moments of the La_2/3Sr_1/3MnO₃ and SrRuO₃ layers reverse independently, and the La_2/3Sr_1/3MnO₃ layer retains bulk-like magnetic properties.