HBF4溶液中全铅液流电池

报道了一种HBF₄水溶液中的全铅液流电池,正、负电极电解液均采用Pb（BF₄）₂的HBF₄水溶液.在酸性的四氟硼酸铅电解液中考察了石墨电极和玻碳电极作为工作电极的循环伏安性能,石墨电极较适于用作全铅液流电池的正、负电极.采用石墨电极作为电池的正、负电极并在四氟硼酸铅酸性电解液中进行充放电实验,其中Pb（BF₄）₂浓度分别为0.5、1.0和1.5 mol·L^-1,且保持游离的HBF₄浓度为1.0 mol·L^-1.该电池为单液流电池,不需要隔膜分隔正、负极的电解液,电流密度为10、20和40 mA.cm^-2,当限定充电容量为7.0 mAh.cm^-2,放电电压截止到1.0 V时,平均库仑效率大于87%,平均能量效率大于68%;当电解液采用1.0或1.5 mol·L^-1 Pb（BF₄）₂+1.0 mol·L^-1HBF₄水溶液时,在10及20 mA.cm^-2电流下的能量效率最高可超过74%.     

完善我国孤儿抚养体系的思考

目前我国对孤儿主要采取集中抚养与分散抚养相结合的方式,面对庞大的孤儿群体,我国孤儿抚养在信息排查、立法与管理、收养制度等方面尚存在亟待改进的问题,因此,完善孤儿抚养体系是我国发展儿童福利事业的必然要求.     

“一题多解”教学的点滴体会

本文阐述了“一题多解”教学对开发学生智力和培养学生能力方面所起的重要作用。     

三氯化氮气体喷射自发分解实验研究

 在气体流动管中对三氯化氮气体喷射自发分解的现象进行了初步实验研究。在一根长80 cm，直径4 cm的圆柱形石英玻璃管中，用喷嘴向气体流动管内喷射NCl₃/He混合气体，观察到了NCl₃喷射分解时的红色火焰。测量了火焰光谱并进行了归属，认为该光谱是Cl₂(B→X)辐射跃迁。NCl­₃的喷射自发分解本质上是激波诱导发生的，即分子的动能转化为分子内能而引起的，生成的Cl原子及NCl₂自由基与NCl₃分子反应，从而得到持续燃烧火焰。实验结果表明了NCl₃自发分解反应可代替放电或燃烧作为Cl原子的来源。     

Structure relations for monic orthogonal polynomials in two discrete variables

In this paper, extensions of several relations linking differences of bivariate discrete orthogonal polynomials and polynomials themselves are given, by using an appropriate vector–matrix notation. Three-term recurrence relations are presented for the partial differences of the monic polynomial solutions of admissible second order partial difference equation of hypergeometric type. Structure relations, difference representations as well as lowering and raising operators are obtained. Finally, expressions for all matrix coefficients appearing in these finite-type relations are explicitly presented for a finite set of Hahn and Kravchuk orthogonal polynomials.     

HL-2M 装置固态亚毫米波干涉系统研制

发展了一套固态亚毫米波外差干涉系统和一种基于全相位快速傅里叶变换(apFFT)的相位处理方法用 于测量 HL-2M 初始等离子体电子密度。该系统采用平面型二极管倍频技术对低频的锁相微波源进行高次倍频以 产生功率大于 0.1MW、频率 306.9GHz 的探测波。基于 apFFT 的相位处理数值算法可以从原始信号中提取相位信 息,缓解由可能的高水平密度扰动导致的相位跳变。系统的固有时间分辨率为 5μs,电子密度测量范围在 10¹⁶~10²⁰m⁻³。在 HL-2M 装置首次实验期间,该系统被安装在中平面上,利用装置内壁反射实现干涉测量,成功 测量了线平均电子密度。      

全媒体环境下城乡科技信息服务

从分析城镇化、镇街产业升级发展,要加快推进农业现代化,需要科技信息服务的支撑,提示了全媒体技术在城乡科技信息服务的作用.以佛山城乡一体化发展为例,对全媒体时代城乡科技信息服务的发展策略进行论述.利用全媒体技术加强科技信息资源的建设与资源共享,构筑面向佛山城乡一体化发展的科技信息服务体系,提高城乡科技信息服务水平,为佛山城乡的社会经济发展提供充分的科技信息资源保障与服务.     

Efficient anti-stokes signal generation through degenerate four wave mixing in an all solid photonic bandgap fiber

We reported the generation of visible red light through degenerate four wave mixing (FWM) in an all solid photonic bandgap fiber (PBGF), which was achieved by pumping the fiber with a 800 nm Ti:sapphire-based femtosecond pulse laser. At a fiber length of 30 m, a broadband anti-Stokes spectrum range from 620 nm to 740 nm was obtained at the highest pump power, the spectrum evolution as a function of pump power and propagation distance had been measured. Furthermore, the intensity-dependent parametric gain characteristic is also calculated, which accords well with the experimental results.     

All-optical method of developing a phase encoded latch by using EDFA

Optics has already proved its meaningful application in information processing and computation, where the parallelism of light is exploited to achieve the desired result. In this communication a novel concept of all-optical memory unit based on phase encoding process is proposed. The unit is simple in architecture comprising phase sifters, mirrors (M′) and two blocks of Erbium doped fiber amplifier. The optical feedback is supported by use of beam splitters and mirrors. It is independent of intensity and therefore requires a small switching power and can work at a bit rate far above 100 Gb/s.     

Sodium-23 MAS NMR study on nuclear quadrupole interaction in NA(1-x)Ag(x)NO2.

Ag-impurity effects on the first- and second-order quadrupole interaction (QI) at ²³Na site in an isomorphic mixed system, Na_1−xAg_xNO₂ (x=0, 0.0084, 0.026, 0.079, 0.094, 0.16), have been investigated by employing ²³Na (I=3/2) magic angle spinning nuclear magnetic resonance (MAS NMR) technique. The central transition (CT) and satellite transition (ST) are simultaneously observed with this system. From the spectral analysis, the quadrupole parameter and its distribution width are obtained as a function of Ag concentration. From the intensity loss of CT MAS centerband and of the envelope function of ST MAS sidebands due to impurities, the range of their influence on the second- and first-order QI is estimated. The estimated ranges contain the second and first neighbouring Na sites from the resonating ²³Na nucleus for the first- and second-order QI, respectively.