广义的一维Fibonacci结构

本文提出一维k组元的Fibonacci结构,它包含k个无公度的基本长度,是具有两个基本长度的标准Fibonacci结构的自然推广,投影理论被用来处理它的X射线衍射花样及其指标化问题,理论模拟被用于验证投影理论的结果,值得注意的是,对于有限的链长,当k足够大时,它的衍射谱将趋于混沌。 关键词：     

金属有机化学气相沉积法制备钛酸铅铁电薄膜

利用低压ＭＯＣＶＤ工艺分别在（００１）取向的ＬａＡｌＯ_３，ＳｒＴｉＯ_３和重掺杂硅单晶衬底上制备ＰｂＴｉＯ_３铁电薄膜，并通过Ｘ射线衍射谱对薄膜的微结构进行分析．Ｘ射线θ－２θ扫描显示硅衬底上得到了ＰｂＴｉＯ_３多晶薄膜，另两种衬底上得到了择优取向的ＰｂＴｉＯ_３薄膜．ＬａＡｌＯ_３衬底上的ＰｂＴｉＯ_３薄膜有ａ和ｃ两个取向，也就是薄膜中存在着９０°畴结构，而生长在ＳｒＴｉＯ_３衬底上的ＰｂＴｉＯ_３薄膜中只存在ｃ方向的择优取向．由于薄膜的尺度效应，发现ｃ轴晶格常数与块材相比均缩短．Ｘ射线的φ扫描验证了后两类薄膜的外延特性，利用同步辐射的高强度和高能量分辨率用摇摆曲线方法研究了这两种外延薄膜的品质，进一步证明了ＳｒＴｉＯ_３衬底上的ＰｂＴｉＯ_３薄膜的单畴特性．利用重掺杂的硅衬底作底电极，测量显示直接生长于硅衬底上的ＰｂＴｉＯ_３多晶薄膜具有良好的铁电性能 关键词：     

Si1－xGex/Si量子阱发光材料的分子束外延生长及其结构研究

采用固源Si分子束外延,在较高的生长温度于Si(100)衬底上制备出Si1－xGex/Si量子阱发光材料。发光样品的质量和特性通过卢瑟福背散射、X射线双晶衍射及光致发光评估。背散射实验中观察到应变超晶格的反常沟道效应;X射线分析表明材料的生长是共度的、无应力释放的,结晶完整性好。低温光致发光主要是外延合金量子阱中带边激子的无声发射和横光学声子参与的激子复合。并讨论了生长温度对量于阱发光的影响。     

Study of Strange Quark Mass in CFL Phase

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Effective-Field Theory on High Spin Systems with Biaxial Crystal Field

Based on the effective-field theory with self-spin correlations and the differential operator technique,physical properties of the spin-2 system with biaxial crystal field on the simple cubic, body-centered cubic, as well as faced-centered lattice have been studied. The influences of the external longitudinal magnetic field on the magnetization,internal energy, specific heat, and susceptibility have been discussed in detail. The phenomenon that the magnetization in the ground state shows quantum effects produced by the biaxial transverse crystal field has been found.     

Low-Temperature Magnetic Properties of Co Antidot Array

Cobalt antidot arrays with different thicknesses are fabricated by rf magnetron sputtering onto porous alumina substrates. Scanning electron microscopy and grazing incidence x-ray diffraction are employed to characterize the morphology and crystal structure of the antidot array, respectively. The temperature dependence of magnetic properties shows that in the temperature range 5K--300K, coercivity and squareness increase firstly, reach their maximum values, then decrease. The anomalous temperature dependences of coercivity and squareness are discussed by considering the pinning effect of the antidot and the magnetocrystalline anisotropy.     

Synthesis of Dimethyl Carbonate from CO2 , Methanol, and Epoxides Using Re（CO） 5 Cl/K2 CO3 as Catalyst System

IntroductionOver the past few years, dimethyl carbonate(DMC) has been proven to be an efficientmethylating,methoxylating, and methoxycarbonylating agent inorganic syntheses, in which DMC is used to replace thetoxic methyl halides, dimethyl sulfate or carb     

磁控溅射技术制备ZnO透光薄膜

采用RF磁控溅射方法,在玻璃衬底上制备了择优取向的ZnO薄膜;通过台阶仪、X射线衍射技术、原子力显微镜和分光光度计分别测量了不同溅射功率条件下淀积的ZnO薄膜厚度(淀积速率)、结晶质量、表面形貌与粗糙度、透光光谱,报道了该薄膜结晶质量、薄膜粗糙度与其在可见光区透光率的关系.     

裂解气相色谱质谱法研究增塑剂邻苯二甲酸二甲酯的热降解机理

用裂解气相色谱-质谱联用方法研究了橡胶产品中使用的增塑剂邻苯二甲酸二甲酯(DMP)在不同温度条件下的热裂解行为.对不同温度条件下裂解产物的分析表明,在初始阶段DMP的裂解产物主要为二氧化碳、苯、甲苯和苯甲酸甲酯.随着温度的升高苯甲酸甲酯进一步裂解成为分子质量更小的自由基,并发生稠环化反应形成更稳定的菲、蒽、间-联三苯、三亚苯等芳香族多环化合物.根据分析实验提供的裂解产物信息和有机物热裂解化学反应的原理对DMP的热裂解反应机理作了探讨,表明在废旧合成橡胶热裂解回收过程中,增塑剂DMP的高温裂解会产生多环芳烃污染物.应选择合适裂解工艺和裂解温度,以减少对环境的污染.     

SUN5500小型机MPI编程与蕴式并行计算的实现方法

基于SUN5500小型计算机并行开发环境，给出了消息传递模型和蕴式行模型的实现方法，通过实例分析了SUNMPI实际编程，并对选取不同模型有不同参数的运算时间进行了比较，结果表明，在SUN5500计算机上MPI模型和蕴式并行模型均能较大地提高运算速度，而且MPI在灵活性和并行程度方面更优。