超长氧化锌纳米线的制备及其气敏性能和紫外传感应用研究

采用一种无需催化剂和载气的简便碳热还原法制得长度约为100 μm、直径约为500 nm、长径比达到200的超长ZnO纳米线,讨论了Si基底位置、沉积时间以及反应物原料的量对ZnO纳米线形貌的影响。对ZnO纳米线的气敏性能进行研究,结果表明：在工作温度为350 ℃时,ZnO纳米线传感器能够很好地检测酒精气体,具有选择性好、响应恢复快的优点,且最低检测体积分数为5×10^-6。另外,通过一种简单、实用的介电泳法制得基于ZnO纳米线的紫外传感器。在365 nm紫外灯照射下,光电流增加了13%;而在254 nm紫外灯照射时,光电流则没发生变化,说明该传感器对不同波长的紫外光有一定的选择性。     

深水半潜式支持平台火灾烟气蔓延规律

基于火灾动力学模拟软件中的数值计算方法对深水半潜式支持平台的火灾烟气蔓延规律开展研究.根据火灾布置最不利原则设计4类火灾工况;研究烟气沿楼梯向上蔓延能力的分布规律及其对温度、能见度、CO体积分数的极值在各层甲板楼梯口分布的影响;分析火源层高度对烟气充满甲板所需时间的分布规律及烟气蔓延路径的影响.研究结果表明:随着楼梯与火源之间距离的减小,烟气沿楼梯向上蔓延的能力增强;火源层以上甲板的最高温度及能见度达到临界条件的最短时间、最高CO体积分数均位于烟气向上蔓延能力强的楼梯口;随着火源层高度的增加,烟气充满火源层以上甲板所需时间有所减少,充满火源层以下甲板所需时间有所增加.研究结果可为火灾中人员的疏散路径规划及深水半潜式支持平台的消防设计优化提供一定的理论指导依据.     

An Approximation of the Steady Gravity Wave Induced by Mountainous Topography

An approximation of the orography gravity wave, which is induced by mountainous topography, is considered in this study. By assuming that the horizontal wind is a linear function with respect to the height, the approximating equation for the orography gravity waves is obtained. Four topography functions are considered in this study and the orography gravity wave are obtained. The dynamics of the orography gravity wave is then discussed by considering the effect of the surface topography and background horizontal wind.     

Nonlinear Periodic Boundary Value Problem for Second Order Integro-differential Equations of Volterra Type

The periodic boundary value problem for a class of second order nonlinear integro-differential equations are disussed by using the monotone iterative technique. The open problem raised by Lakshmikantham in 1986 is solved.     

溶剂热制备氧化锌纳米线

ZnO nanowires were synthesized mildly through an absolute alcohol solvothermal process at 120 ℃ for 12 h using ZnAc₂·2H₂O and NaOH as raw materials and PEG400 as a soft template. The cyrstal structure and morphology of the nanowires were characterized by XRD, SEM, TEM and HRTEM. The results indicate that the diameter of ZnO nanowires is 40 nm, the length can reach 2 μm and the nanowires are of high purity, homogeneity and well crystallinty. The influence of the various factors on the formation of ZnO nanowires and formation mechanism were also discussed.     

QUASI-PERIODIC SOLUTIONS ANDSUB-HARMONIC BIFURCATION OF DUFFING'S EQUATIONS WITH QUASI-PERIODIC PERTURBATION

1.IntroductionInthispaperweconsidertheDuffing'sequationofthefollowingtype:whereg,fi,fZaresmallparameterswithorderO(E),6isasmallparameterwithorderO(E')'coscallac=afl ac,n=3,5,05e<<1.alandwZarenotrationalrelated,i.e.,f(t)=f,coswit jZcoswZtisaquasi-periodicfunction.Duffing'sequationwithoneexternalforcingtermiseXtensivelystudied,forexample,see[1--7].Duffing'sequationwithtwoperiodicexternalforcingtermsisalsoanalyzed,see[7-10].In[11,121theauthorsstudiedthedynamicsofaweaklynonlinearsystemsubjecte…