用两端对称缺陷复合光子晶体实现多通道滤波和光开关

用传输矩阵法计算了两端对称缺陷复合光子晶体结构的光传输特性。计算结果表明:两端对称缺陷复合光子晶体[D(AB)mD]2结构中的禁带出现两个完全共振透射峰。通过控制入射光强来微调光子晶体材料的介电常数,使得完全共振透射峰移动,且介电常数变化越大,共振透射峰偏移越大,从而形成高效率的双通道光开关。当光子晶体为[D(AB)mD]N结构时,每个完全共振透射峰都分裂为N-1条,这样可通过调节N同时实现所需要通道数目的高效多通道光开关和多通道滤波器。     

抛物面型X射线组合折射透镜聚焦性能的理论与实验研究

结合衍射理论和矩阵光学方法得出抛物面型X射线组合折射透镜的光学性能指标(包括其焦距的严格表达式、薄透镜近似的判定准则、透过率和有效孔径,以及极限聚焦光斑尺寸等).采用X射线深度光刻技术实际制作了PMMA材料抛物面型X射线组合折射透镜并给出了工艺测试结果.最后在北京同步辐射装置(BSRF)上,实际构建了基于3种不同结构参数的PMMA材料抛物面型X射线组合折射透镜的微束聚焦实验系统.并实际测试了其聚焦性能,均获得了良好的聚焦效果,给出实测结果并对实测结果进行了分析和讨论.     

环状氮氢化合物NnHn(n=3~5)的构象研究

应用密度泛函理论对10种环状氮氢化合物异构体进行了研究.利用自然键轨道理论(NBO)和分子中的原子理论(AIM)分析了这些异构体的成键特征、相对稳定性.N-N键长与键临界点的电荷密度存在反比关系.超共轭作用和立体排斥作用计算表明:立体排斥作用和超共轭作用在决定构象稳定性的方面均起了主要的作用.H原子的相对位置的差异影响了键-键立体排斥能的类型.     

NEW EXPLICIT AND EXACT TRAVELLING WAVE SOLUTIONS FOR A COMPOUND KdV－BURGERS EQUATION

In this paper, new explicit and exact travelling wave solutions for a compound KdV－Burgers equation are obtained by using the hyperbola function method and the Wu elimination method, which include new solitary wave solutions and periodic solutions. Particularly important cases of the equation, such as the compound KdV, mKdV－Burgers and mKdV equations can be solved by this method. The method can also solve other nonlinear partial differential equations.     

具有复合幂函数和共存吸引子的新混沌系统的动力学分析与电路仿真

构造一个具有复合幂函数的三维连续自治混沌系统。系统的状态方程仅有5项,其中一项是指数小于1的复合幂函数。该系统具有结构简单、非双曲平衡点、吸引子共存的性质,展现出了复杂的动力学行为。首先,对系统的动力学行为进行分析,包括李雅普诺夫（Lyapunov）指数谱、分岔图以及庞加莱映射等,结果表明此系统具有混沌特性。然后进行混沌系统的电路设计,电路仿真结果验证了理论分析的正确性。     

Structure comparison between Th2Zn17-type and TbCu7-type Sm–Fe intermetallic compounds and their nitrides by means of 57Fe-Mössbauer spectroscopy

Samarium–iron intermetallic compounds were prepared by a melt spinning method with low and high wheel speeds, which resulted in a Th₂Zn₁₇-type and a TbCu₇-type structure, respectively. Structure comparison between these types was investigated for Sm–Fe intermetallic compounds and their nitrides by ⁵⁷Fe-Mössbauer spectroscopy.     

Effects of preheating on diaspore: Modifications in colour centres, structure and light emission

The thermal properties and thermal stability of diaspore-corundum (AlOOH-Al₂O₃), from Goian (Pontevedra, Spain) were studied by means of differential thermal analysis (DTA), thermogravimetry (TG), high temperature X-ray diffraction (HTXRD) and thermally stimulated luminescence (TL) techniques. The samples were annealed to link the combined effect of (i) dehydroxylation, (ii) oxidation-reduction of chromophores (Mn 0.5%, Fe₂O₃ 0.12%, TiO₂ 0.021% and Cr 80 ppm) determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and (iii) phase transitions whilst sample heating (i.e. α-AlOOH→α′-Al₂P₃→α-Al₂O₃). The blue colour of diaspore, attributed to the Ti⁴⁺-Fe²⁺ intervalence-charge-transfer mechanism, turns to white (circa 500 °C) in good agreement with the DTA endothermic peak (dehydroxylation). The coexistence of α-AlOOH and α′-Al₂P₃ phases has been detected by in situ HTXRD and could be correlated to the thermoluminescence tests performed on preheated aliquots (up to 500 °C).     

Langevin study of neutron emission in the reactions ^16O＋^181Ta and ^19F＋^178Hf^＊

The pre-scission neutrons measured in the reactions 16O 181Ta and 19F 178Hf are studied via a Langevin equation coupled with a statistical decay model. We find that because of the mass asymmetry of different entrance channels, the spin distributions of compound nuclei would be different, consequently, the measured neutrons in these two reactions would also different. This means that the entrance channel will affect the particle emission in the fission process of hot nuclei.     

Substituent effects on gas‐phase homolytic Fe–N bond energies of m‐G‐C6H4NHFe(CO)2(η5‐C5H5) and m‐G‐C6H4N(COMe)Fe(CO)2(η5‐C5H5) studied using density functional theory methods

One of the most fundamental properties in chemistry is the bond dissociation energy, the energy required to break a specific bond of a molecule. In this paper, the Fe–N homolytic bond dissociation energies [ΔH_homo(Fe–N)'s] of 2 series of (meta‐substituted anilinyl)dicarbonyl(η⁵‐cyclopentadienyl) iron [m‐G‐C₆H₄NHFp ( 1 )] and (meta‐substituted α‐acetylanilinyl)dicarbonyl(η⁵‐cyclopentadienyl) iron [m‐G‐C₆H₄N(COMe)Fp ( 2 )] were studied using density functional theory methods with large basis sets. In this study, Fp is (η⁵‐C₅H₅)Fe(CO)₂, and G is NO₂, CN, COMe, CO₂Me, CF₃, Br, Cl, F, H, Me, MeO, and NMe₂. The results show that Tao‐Perdew‐Staroverov‐Scuseria, Minnesota 2006, and Becke's power‐series ansatz from 1997 with dispersion corrections functionals can provide the best price/performance ratio and accurate predictions of ΔH_homo(Fe–N)'s. The ΔΔH_homo(Fe–N)'s ( 1 and 2 ) conform to the captodative principle. The polar effects of the meta‐substituents show the dominant role to the magnitudes of ΔΔH_homo(Fe–N)'s. σ_α· and σ_c· values for meta‐substituents are all related to polar effects. Spin‐delocalization effects of the meta‐substituents in ΔΔH_homo(Fe–N)'s are small but not necessarily zero. RE plays an important role in determining the net substituent effects on ΔH_homo(Fe–N)'s. Insight from this work may help the design of more effective catalytic processes.     

两端对称负折射率缺陷复合光子晶体:多通道滤波和光开关

采用传输矩阵法对两端对称负折射率缺陷复合光子晶体结构[D(AB)mD]N的透射特性进行了研究.结果表明:当N=2时,该结构透射谱的禁带出现两个完全共振透射峰,当N增加时,每个共振透射峰又分裂为N-1条;当复合光子晶体的层数m逐渐增加时,透射峰的品质因子逐渐提高,且分裂的共振透射峰距离逐渐减少;既为该结构实现高品质的多通...