使用色散可调啁啾光纤光栅在常规单模光纤中实现超过100km,10Gb/s的转输 *

报道了用简单的应力方法使均匀光栅成为线性啁啾光纤光栅的技术 ,并推导出了相应理论 ,发现最大色散补偿带宽与色散的乘积近似为常数 .在常规单模光纤G652,10Gb/s系统中实现超过100km的色散补偿 .     

三维光存储中折射率失配引起的球差补偿

为实现三维光存储中折射率失配引起的球差补偿,建立了光学存储系统模型,获得了折射率失配引起的波前偏差函数与存储深度的表达式.采用泽尔尼克循环多项式对波前偏差函数进行补偿展开.在双光子荧光和单光子共焦荧光读出方式下,均可获得读出荧光强度与存储深度的关系:在折射率失配引起的球差未得到补偿矫正的情况下,存储深度在200 μm左右读出荧光强度基本上下降为零;当折射率失配引起的初级球差被补偿矫正后,读出荧光强度随存储深度的下降得到较好改善;当折射率失配引起的二级球差被补偿矫正后,存储深度在1 mm内存储点强度随深度基本上没有明显地变化.并且对像差补偿方法进行了具体地分析.     

Crystal structure and chemical bonding of the intermetallic Zintl phase Yb(11)AlSb(9)

High resolution single crystal synchrotron X-ray diffraction data measured at 15(2) K were used to solve the structure of the complex intermetallic Zintl phase, Yb(11)AlSb(9) (space group Iba2), made up of Yb cations and polyanions along with isolated Sb anions. The 15(2) K cell parameters are a = 11.7383(4) ?, b = 12.3600(4) ?, c = 16.6796(6) ?. The temperature dependence of the structure was investigated through high resolution synchrotron powder X-ray diffraction (PXRD) data measured from 90 K to 1000 K. Rietveld refinements of the crystal structure revealed near linear thermal expansion of Yb(11)AlSb(9) with expansion coefficients of 1.49(2) × 10(-5) K(-1), 1.71(3) × 10(-5) K(-1), 1.13(1) × 10(-5) K(-1) for a, b and c, respectively. The chemical bonding in Yb(11)AlSb(9) was analyzed using atomic Hirshfeld surfaces, and the analysis supports the presence of the structural elements of Yb cations, [AlSb(4)](9-) tetrahedra, [Sb(2)](4-) dimers and isolated Sb(3-) anions. However, indications of interatomic interactions between the Zintl anions and the Yb cations were also observed.     

A new bismuth potassium nitrate oxide, Bi1.7K0.9O2(NO3)2: Synthesis, structure, thermal behavior, and photocatalytic properties

We report here the first observation of a bismuth potassium nitrate Bi_1.7K_0.9O₂(NO₃)₂, obtained via thermal decomposition of bismuth and potassium nitrate mixtures. The new compound is orthorhombic, space group Immm (71), Z = 2, with a = 3.8698(7) Å, b = 3.8703(7) Å, and c = 24.1271(4) Å. Its crystal structure was refined from powder X-ray diffraction data by analogy with the mineral beyerite, Bi₂O₂Ca(CO₃)₂. The morphology and elemental composition of Bi_1.7K_0.9O₂(NO₃)₂ were characterized using scanning electron microscopy (SEM) with energy dispersive X-Ray spectroscopy (EDS). Its phase transformations upon heating and products of its thermal decomposition were studied using XRD, TGA and FTIR. At 440 °C, Bi_1.7K_0.9O₂(NO₃)₂ transforms to another basic bismuth potassium nitrate with demonstrates a very similar XRD pattern but slightly larger cell parameters. At 520 °C, the intermediate oxide nitrate decomposes into a mixture of crystalline α-Bi₂O₃ and KNO₃. The as prepared Bi_1.7K_0.9O₂(NO₃)₂ showed lower than TiO₂ (Degussa P25) photocatalytic activity upon decomposition of a widely used model pollutant, Rhodamine B (RhB) and photooxidation of potassium iodide under UV-vis light irradiation. Interaction with potassium iodide in alkaline media resulted in formation of Bi₅O₇I.     

Thermal properties and ion mobility in complex antimony(III) fluorides with α-amino acids

Differential thermal analysis (DTA) and (¹⁹F, ¹H) NMR spectroscopy were used to study thermal properties and ion mobility in complex antimony(III) fluorides with amino acids of composition [(CH₃)₂CH(CH₂)CH(NH₃)COOH]SbF₄ (LeuHSbF₄), SbF₃[(CH₃)₂CH(CH₂)CH(⁺NH₃)COO^?] (SbF₃ · Leu), and SbF₃[(CH₃)₂CHCH(⁺NH₃)COO^?] (SbF₃ · Val). Ionic conductivity in L-leucinium tetrafluoroantimonate(III) was studied using impedance spectroscopy. LeuHSbF₄ was found to undergo a diffusion phase transition to a relatively highly conductive state in the range 385?C415 K with an attendant loss of thermal stability (softening) of the high-temperature phase.     

高温高密度氦的压缩特性及其结构的分子动力学模拟

用分子动力学方法和不同参数的指数 6势函数计算了T =30 4K的高密度氦的等温压缩线和能量分布 .给出了能精确描述高密度氦原子间相互作用的指数 6势函数优化参数 .并用优化的势函数计算了高密度氦T =30 0K和T =2 98K的等温压缩线 ,计算结果和实验值非常吻合 .进一步用优化的势函数模拟了高温高密度氦的状态方程及其结构 ,发现当把 ρ限定为 1 .6 0g /cm³ 时 ,其径向分布函数的第 2个峰将在 2 0 0 0～ 30 40K区间消失 ,表明此时发生了固 液相变过程 .     

锂离子电池硅基负极材料的研究进展

硅基材料是新一代高容量锂离子蓄电池负极材料的典型代表,近年来已成为理论研究和应用研究的热点.本文介绍了锂离子电池硅基负极材料的制备方法、电化学性能及其研究现状,分析了硅材料作为锂离子电池负极材料存在的问题;讨论了硅材料作为锂离子电池负极材料的研究前景.并指出若能克服目前存在问题,将有望成为新一代锂离子电池负极材料.     

The Coherent Production of the (K +π0) System by K + Beam on Copper Nuclei at the OKA Setup

Journal of Experimental and Theoretical Physics - On the statistics of ~1.7 × 108 interactions of positively charged kaons on copper nuclei, coherent events of the K+π0 system production...     

Ionic Conductivity of Composite Solid Electrolytes (C4H9)4NBF4–Al2O3

Russian Journal of Electrochemistry - Composite solid electrolytes (C4H9)4NBF4–Al2O3 are synthesized in a wide range of composition. Their thermal, structural, and conducting properties are...     

An iterative regularization method for the 2-constrained pseudoinversion of an operator equation

An iterative regularization algorithm is proposed for solving a special optimization problem, the so-called 2-constrained operator pseudoinversion. The convergence of the algorithm is examined in the case of perturbed input data. An error estimate is derived, and an a priori choice of the regularization parameters is described. The algorithm is applied to an optimal control problem with minimal costs.