Particle-in-cell simulation of ion-acoustic solitary waves in a bounded plasma

We study some nonlinear waves in a viscous plasma which is confined in a finite cylinder.By averaging the physical quantities on the radial direction in some cases,we reduce this system to a simple one-dimensional model.It seems that the effects of the bounded geometry(the radius of the cylinder in this case)can be included in the damping coefficient.We notice that the amplitudes of both Korteweg–de Vries(KdV)solitary waves and dark envelope solitary waves decrease exponentially as time increases from the particle-in-cell(PIC)simulation.The dependence of damping coefficient on the cylinder radius and the viscosity coefficient is also obtained numerically and analytically.Both are in good agreement.By using a definition,we give a condition whether a solitary wave exists in a bounded plasma.Moreover,some of potential applications in laboratory experiments are suggested.     

Quantum Fisher Information Gap for Systems with Nonlinear Hamiltonians

Quantum Fisher information(QFI) gap characterizes the stability of QFI to space directions. We study the QFI distributions and QFI gap for quantum states generated from nonlinear Hamiltonians for both spin and bosonic systems. We find that the same spin-squeezing parameter(or principle squeezing parameter) corresponds to two different values QFI gap, and the locations of all extreme points of the QFI are explicitly given.     

Pt-MoOx/CNT电极的制备及其对乙醇氧化电催化性能研究

MoOx,a non-noble secondary catalyst instead of noble metal Ru,was dispersed on carbon nanotubes(CNT)andthen the primary catalyst Pt was electrodeposited on MoO_x/CNT/graphite electrode by potential-step method.CNTused was grown directly on graphite disk by chemical vapor deposition.The Pt-MoO_x/CNT/graphite electrode wascharacterized by scanning electron microscopy and energy dispersive X-ray spectroscopy.The electrocatalyticproperty and the long-term cyclic stability of Pt-MoO_x/CNT/graphite electrode for ethanol oxidation have been in-vestigated in 1.0 mol/L CH_3CH_2OH 0.1 mol/L H_2SO_4 by cyclic voltammetry.On the other hand,the effect of theloading mass of MoO_x on specific activity of Pt-MoO_x/CNT/graphite electrode and the activation energy of ethanoloxidation were investigated.The Pt-MoO_x/CNT/graphite electrode shows good long-term cyclic stability.82%value of peak current density at the oxidation peak around 0.69 V(vs.SCE)remains after 500 cycles,which ishigher than those of Pt/CNT/graphite and Pt-Ru/CNT/graphite electrodes with the corresponding values of 55% and72%,respectively.     

6-氟-2,4-二苯基喹啉的合成与晶体结构

合成了一种新的喹啉衍生物6-氟-2,4-二苯基喹啉(FDPQ),并且测定了该化合物的晶体结构.该晶体属于单斜晶系,P2(1)/c空间群.     

超导储能磁体电流补偿分布式2.5 D分析方法

研究了闭环高温超导储能磁体在非均匀交流外磁场下电流补偿过程中的分布式2.5 D分析方法。在77 K下对磁体电流补偿过程进行了H算法数值研究,H算法几何结构和求解域采用分布式2.5 D分解并配合BP神经网络进行求解。结果表明,所提算法能以更快的速度收敛,并保持理想的精度;此外,磁体在10～70 mT外磁场下能保持较好的电磁稳定性。     

具有生理活性的含氧、氮、硫杂原子螺环化合物的研究进展

综述了近年来部分具有生理活性螺环化合物的研究进展, 重点介绍了这类化合物的结构特征、生理活性和部分化合物的合成方法. 展望了该类螺环化合物的应用前景.     

一种基于无证书生物特征数据的签名方案

在基于ID的无证书签名方案的基础上,通过模糊提取器获取生物特征信息来构造密钥,结合CL-PKC私钥生成原理,提出了一种基于生物特征的无证书签名方案.新方案在随机预言模型下是可证安全的,而且能够抵抗适应性选择消息攻击和ID攻击下的存在性伪造.该方案不仅解决了密钥托管问题而且与传统的方案相比具有较高的效率.     

Synthesis, Crystal Structure, Thermal Behavior and Photoluminescent Property of Complex [Zn(L)(SO4)]·0.5H2O

Complex [Zn(L)(SO4)]·0.5H2O (L= 2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) has been synthesized under hydrothermal conditions. The compound was characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21 /n with a = 9.9916(7), b = 12.3834(9), c = 29.259(2) , β = 97.7720(10)°, V = 3587.0(4)3 , Z = 2, C76H41Cl4F4N16O9S2Zn2 , Mr = 1734.91, Dc = 1.606 g/cm 3 , F(000) = 1754, μ(MoKa) = 0.959 mm -1 , R = 0.0492 and wR = 0.1385. The asymmetric unit of 1 contains one Zn(II) atom, two L ligands, one sulfate anion and half a water molecule. Each Zn(II) atom is five-coordinated by four nitrogen atoms from two different L ligands and one sulfate oxygen atom in a tetragonal pyramidal coordination environment. The N-H···O hydrogen bonds link the discrete structure of 1 into a 2D supramolecular architecture. The photoluminescent property of 1 has also been studied in the solid state at room temperature.     

一个由4，4’-（丁烷-1，4-二氧基）-二苯甲酸和双咪唑配体构筑的三重穿插金属有机骨架化合物

采用水热法合成了1个二维缠结金属有机框架化合物[Cu（bbi）_0.5（boba）]_n（1）（bbi=1,1’-（1,4-丁烷基）-二（咪唑）;H₂boba=4,4’-（丁烷-1,4-二氧基）-二苯甲酸）,并通过元素分析、红外光谱和单晶X-射线衍射对其进行了结构表征。结构分析显示：化合物1是具有聚轮烷和聚锁烃结构特征的三重平行穿插网络。此外还研究了它的荧光和热稳定性。     

Pt 纳米颗粒在聚二甲基二烯丙基氯化铵功能化碳纳米管上的自发沉积及其对甲醇的电氧化性能

利用聚二甲基二烯丙基氯化铵(PDDA)非共价修饰的碳纳米管(CNTs)与PtCl₆^2-之间的自发氧化还原作用, 制备了Pt 纳米颗粒(Pt NPs)/CNTs-PDDA复合催化剂. PDDA在该催化剂中具有三种作用: (1) 作为金属前驱体PtCl₆^2-还原为Pt NPs 的还原剂; (2) 作为原位产生的Pt NPs 的稳定剂; (3) 在CNTs 表面形成保护膜抑制CNTs 在甲醇电催化氧化过程中的腐蚀. 采用傅里叶变换红外(FTIR)光谱、热重分析和拉曼光谱对CNTs-PDDA进行了表征, 表明PDDA通过π-π作用已成功覆盖在CNTs 表面, 并且修饰过程没有导致CNTs 结构的破坏. 采用透射电子显微镜(TEM)对Pt NPs/CNTs-PDDA 催化剂进行了表征, 结果表明, Pt NPs 均匀地分散在CNTs上, 平均粒径约2 nm, 且粒径分布范围窄. 用循环伏安法、计时电流法进一步考察了Pt NPs/CNTs-PDDA催化剂在酸性介质中对甲醇的电催化氧化的性能. 电化学测试结果表明, 与原始CNTs 负载的Pt NPs催化剂相比,Pt NPs/CNTs-PDDA催化剂具有更高的电化学活性表面积、电催化质量比活性和稳定性.