电解液对全铅单液流电池电极性能的影响

研究Pb(II)和H+离子浓度对全铅单液流电池正、负电极在复合石墨基体上电化学行为的影响.结果表明,PbO2正极和Pb负极的电极过程受电化学和扩散混合控制.Pb(II)氧化沉积成PbO2时出现成核环,铅负极成核过电位小,充放电电压差远小于PbO2正极,电池极化主要来自PbO2正极.增加H+浓度有利于降低PbO2正极和Pb负极的极化,但析氧、析氢副反应和腐蚀加重.增大Pb(II)浓度有利于抑制析氧,但PbO2正极充电电压升高,充放电电压差增大.Pb(II)浓度较低时,充放电过程中PbO2沉积层少许脱落,充电电压进一步降低且更趋平稳.为此,电解液中HBF4浓度以2 mol L-1为宜,Pb(II)浓度应在0.9 mol L-1以上.     

An All Solid State Potentiometric Sensor for Monohydrogen Phosphate Ions

An all solid state potentiometric sensor using anthracene thiourea derivative as ionophore was developed. It exhibited a near‐Nernstian slope of 30.8±1.0 mV/decade of activity for HPO₄^2? ions in the concentration range of 1.0×10^?7–1.0×10^?3 M at pH 7.4. It displayed excellent selectivity for monohydrogen phosphate over other anions and the selectivity sequence was determined as HPO₄^2?>SO₄^2?>Cl^?>NO₃^?>OAc^?>I^?>ClO₄^?. The developed sensor was evaluated for the analysis of monohydrogen phosphate ions in a standard reference material (SRM 1548) as well as in the potentiometric titration of phosphate ions with a barium chloride solution.     

All optical switching in azo-polymer planar waveguide

In this paper all optical switching in planar methyl red doped poly (methyl methacrylate) (MR/PMMA) waveguide and the effects of different parameters on this process are presented. Switching was achieved by a 488 nm Ar ion laser (pump beam) on a 633 nm He-Ne laser (probe beam) when passed through the waveguide. The effect of temperature and pump intensity, polarization and chopping frequency on switching is investigated. The switching process is attributed to trans-cis-trans photoisomerization of azo dyes in the polymer host. By studying the absorption spectrum of the sample, it is shown that both pump and probe laser beams are effective on the switching process.     

A method of implementation of frequency encoded all optical logic gates based on non-linear total reflectional switch at the interface

A novel method of implementation of frequency encoded logic gates NOT, OR, AND, NOR, NAND, X-OR, X-NOR is discussed. The frequency sources and physical requirements for the implementation are also discussed. The non-linear material (liquid) suitable for these operations to be performed should be of large non-linear coefficient, high reverse saturation absorption, large thermo-optic coefficient and low viscosity. The input controlling beams used to induce non-linearity in the switch are either of frequency υ₁ or υ₂ and the probe beam is a mixed signal of frequencies υ₁ and υ₂. Depending on the nature of the controlling inputs the output conditions of the probe can be adjusted to get different logic gates.     

All Set and Intelligent Bargaining Control Model

1Introduction Thevigorousdevelopmentofneweconomyaffectstheworld onvariousfieldandE businessisthetypicalresultofthis economywave.Comparedwithtraditionalbusinessmode,newonerealizesnon distancecommunicationofE2Cand E2Emakingfulluseofinternetallovertheworld.Thenon distancecommunicationbringsunlimitedbenefitsto companies.Atthesametimewenoticethatpeopleshould combineE businesswithcomputersciencesufficientlytaking advantageoftherelationshipbetweenthem,inadditionto movingtheoldcommonbusinesstointer…     

在WDM全光网络上构建上层网络的路由算法

在WDM全光网络上构建上层网络需要考虑上层网络的保护机制.上层网络按保护机制可分为最大故障链路数保护网和连通保护网.针对它们的不同特点给出了构建两类上层网络并使费用最低的启发式路由算法.与已有方法相比,具有算法简单,时间复杂性小,容易实用化的特点.大量的模拟计算也证明了算法的正确性.     

构造d维各向同性谐振子四类升降算子的一种方法P

文中得到d维各向同性谐振子归一化径向波函数. 在径向基本算子r,(1)/(r),(d)/(dr)的基础上,可以直接构造d维各向同性谐振子的四类升降算子,同时也得到它们的归一化系数.     

分散橙25掺杂的聚合物PMMA薄膜全光极化的研究

制备了以分散橙25为客体的掺杂型有机聚合物PMMA薄膜样品，对之进行了全光极化研究，极化使薄膜产生诱导二阶非线性光学效应，种子光的强度越大，其二阶非线性极化率达到的饱和值越大;种子光的位相差、相对强度比、光场强度等因素影响薄膜的二阶非线性的优劣.     

On the Ramsey numbers R(3, 8) and R(3, 9)

Using methods developed by Graver and Yackel, and various computer algorithms, we show that 28 ≤ R(3, 8) ≤ 29, and R(3, 9) = 36, where R(k, l) is the classical Ramsey number for 2-coloring the edges of a complete graph.     

An arbitrarily oriented crack in a semi-infinite medium with a surface layer under tension

The title problem is analyzed by the use of the continuous distribution of dislocations in the framework of plane elastostatics. A set of singular integral equations for the dislocation density is readily set up, whose solution is obtained in the form of the product of the series of Chebyshev polynomials of the first kind and their weight function. The variation of the stress intensity factor due to the geometrical configuration and the material combination is shown in graphs. The probable angle of crack growth due to Erdogan-Sih criterion for brittle materials is also shown.