Electrooxidation of carbo/thiocarbohydrazide and their hydrazone derivatives at a glassy carbon electrode

Electrochemical oxidation of thio/carbohydrazide and their hydrazone derivatives Benzaldehyde thiocarbohydrazone [BTCH] diacetylene thiocarbohydrazone [DATCH] have been studied in Brit-ton Robinson buffer in aqueous and nonaqueous media at a glassy carbon electrode. The effects of pH, sweep rate, concentration, temperature and surfactants have been studied. The complex bis (carbo/thiocabohydrazide) Zn(II) chloride was also subjected to voltammetric analysis in order to understand the reactivity both in free and metal bound states. The reaction conditions were optimized for the determination of above compounds in micrograms quantities by differential pulse voltammetry, analytical utility of this investigation is also highlighted.     

The variational Lyapunov function and strict stability theory for differential systems

In this paper, we investigate strict stability of differential systems by variational Lyapunov function. We obtain some sufficient conditions and comparison theorems.     

A necessary and sufficient condition of existence of positive solutions for nonlinear singular differential systems

In this paper, by means of monotone iterative technique, a necessary and sufficient condition of the existence of positive solution for a class of nonlinear singular differential system is established, the results of the existence and uniqueness of the positive solution and the iterative sequence of solution are given. In the end, two classes extending boundary value differential systems are discussed and some further results are obtained.     

Measurement of small-signal and large-signal responses of packaged laser modules at high temperature

In this paper, the pulsed injection method is extended to measure the chip temperature of various packaged laser modules, such as the DFB laser modules, the FP laser modules, and the EML laser modules. An optimal injection condition is obtained by investigating the dependence of the lasing wavelength on the width and period of the injection pulse in a relatively wide temperature range. The small-signal frequency responses and large-signal performances of packaged laser modules at different chip temperature are measured. The adiabatic small-signal modulation characteristics of packaged LD are first extracted. In the large-signal measurement, the effects of chip temperature, bias current and driving signal on the performances of the laser modules are discussed. It has been found that the large-signal performances of the EML modules depend on the different red-shift speeds of the DFB and EAM sections as chip temperature varying, and the optimal characteristics may be achieved at higher temperature.     

Pulsed pump: Thermal effects in solid state lasers under super-Gaussian pulses

Solid state laser (SSL) powers can be realistically scaled when pumped by a real, efficient and multimode pulse. In this work, a fourth-order super-Gaussian pulse was assumed as a pump for SSL’s and a complete analytical expression for the thermal phase shift is given. Moreover, the focal length of thermal lens in paraxial ray approximation regime was studied. The results when applied to a Ti: sapphire crystal show an appreciable correction for abberation compared to a top-hat pulse.     

Differential Pulse Polarographic Determination of Nitrate in AUT Solution

A differential pulse polarographic method for the determination of nitrate ion has been developed. With 0.5 M CaCl₂ as supporting electrolyte, NO^?₃ is reduced to give a peak with E_1/2=–1.836 Volt vs. the Ag/AgCl electrode. The differential pulse polarographic peak height is proportional to the nitrate concentration from 20 to 60 ppm. The detection limit for nitrate is 2 ppm in pure aqueous solution. In the determination of 40 ppm nitrate a relative precision (relative standard deviation) of less than 2% was achieved. Nitrite interferes seriously and should be absent if accurate results are required. The method has been applied to the determination of nitrate in Ammonium Uranyl Tricarbonate (AUT) Solution, results obtained by this method are compared to those obtained by ion chromatography. The agreement between the two sets of results suggests that the DPP method can be used with a fair degree of confidence.     

Semilinear Differential Inclusions in Separable Banach Spaces

Ｓｅｍｉｌｉｎｅａｒ　Ｄｉｆｆｅｒｅｎｔｉａｌ　Ｉｎｃｌｕｓｉｏｎｓ　ｉｎ　Ｓｅｐａｒａｂｌｅ　Ｂａｎａｃｈ　ＳｐａｃｅｓＸｕｅＸｉｎｇｍｅｉ（薛星美）ａｎｄＳｏｎｇＧｕｏｚｈｕ（宋国柱）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，Ｎａｎｊｉｎ...     

两种群竞争模型的奇摄动群

本文应用多重尺度法构造出非线性微分方程组的解的渐近展开式。并用微分不等式的技巧，证明原问题的解的存在性，且给出解的一致有效渐近估计．     

伴有边界摄动的三阶拟线性向量微分方程边值问题的奇摄动

本文研究伴有边界摄动的三阶拟线性向量微分方程边值问题的奇摄动,在适当的假设下,利用对角化技巧和不动点原理证明了摄动问题解的存在唯一性并给出解的任意阶的一致有效的渐近展开式和余项的估计。     

Theoretical analysis on waveform structures of pulse propagating in shallow water with an ideal thermocline

I.IntroductionDuetospatia1andtemporalvariabilityoftheocean-acousticenvironment,especially,theeffectsofboundaryaswel1asmediumonpropagationofacousticwavesinshal1owwater,theacousticpropagationisextrcmelycomp1icatcd.Multipathtransmissionisthebasiccharacteris-hcsofunderwatersoundchannels.Undctcrminedmultipathstructurescangreatlylimittheperformanceofunderwateracousticdetcction.However,ifthemultipathcharacteristicsofacousticpropagationinunderwatcrsoundchanne1sareknown,spaee-timeresolutionandpro-cess…