衬底的Al化处理对AlN性能的影响

研究了衬底的Al化处理对采用MOCVD法在c面蓝宝石衬底上高温生长AlN外延层的影响机制.通过原位监测监控整个外延生长过程,同时对AlN外延层的表面形貌和晶体质量以及应变状态进行表征研究.结果表明衬底的Al化处理导致AlN外延层的表面更加平整但是晶体质量下降,同时对外延层的应变也有很明显的影响.     

湘湖的自然地理及其兴废过程

萧山市湘湖是古代宁绍平原湖泊中众废残存的特例其前身西城湖早已埂废.北 宋 政和二年 (1 112年 ),因农业需要,在特殊的地理环境下又废田复湖.从北宋末至民国 间八百多年对湘湖主禁、主垦两派斗争激烈.1 9 4 9年以来,由于农田水利建设的发展,湘湖原有灌概职能减小,围垦扩大,成为目前一条狭长的河流型湖泊.但湘湖粘土层宜制砖瓦,挖泥造成深潭,出现了又一次还湖的情况,重新恢复的湘湖,为旅游业的发展创造了美 好的前景     

解一维热传导方程的高精度的隐式差分格式

本文对求解一维热传导方程利用待定参数法构造出截断误差为O(Δt~3+Δx~4)的高精度的隐式差分格式,并讨论了其绝对稳定性.     

二维抛物型方程的一族高精度显式差分格式

构造了一族解二维抛物型方程的高精度显格式 ,其稳定性条件为r=Δt/Δx2 =Δt/Δy2 <1 /2 ,截断误差为O(Δt3 +Δx4)     

Effect of alloying Re and Ru in the edge-dislocation core of the Ni/Ni3Al interface

Investigations of alloying Re and Ru in the [110](001) dislocation core of the Ni/Ni3Al interface were conducted within the framework of density functional theory.The energetic calculations show that both elements can stabilize the [110](001) dislocation core.In the dislocation core region,Re and Ru prefer to substitute for Ni on the site in the γ-phase.Re is easier to segregate into the dislocation core region as compared with Ru;it especially prefers to substitute for Ni on the γ-(Ni)1 site.     

与年龄相关的模糊随机种群扩散系统的均方散逸性

讨论了一类与年龄相关的模糊随机种群扩散系统,该系统受随机和模糊两种不确定性因素的影响.在有界的条件(弱于线性增长条件)和Lipschitz条件下,利用It公式和Bellman-Gronwall-Type引理,建立了均方意义下与年龄相关的模糊随机种群扩散系统均方散逸性的判定准则.并通过数值例子对所给出的结论进行了验证.     

Global existence of solutions to a hyperbolic-parabolic system

In this paper, we investigate the global existence of solutions to a hyperbolic-parabolic model of chemotaxis arising in the theory of reinforced random walks. To get -estimates of solutions, we construct a nonnegative convex entropy of the corresponding hyperbolic system. The higher energy estimates are obtained by the energy method and a priori assumptions.

     

Modeling the Transmission of West Nile Virus with {\it Wolbachia} in a Heterogeneous Environment

{\it Wolbachia} are maternally transmitted endosymbiotic bacteria. To investigate the effect of {\it Wolbachia} on the spreading and vanishing of West Nile virus, we construct a reaction-diffusion model associated with the {\it Wolbachia} parameter in a heterogeneous environment, which has nonlinear infectious disease parameters. Based on the spectral radius of next infection operator and the related eigenvalue problem, we present a corresponding explicit expression describing the basic reproduction number. Furthermore, utilizing this number, we not only give out the stability of disease-free equilibrium, but also analyze the uniqueness and globally asymptotic behavior of endemic equilibrium. Our theoretical results and numerical simulations indicate that only if {\it Wolbachia} reach a certain magnitude in mosquitoes, it can be effective in the control of West Nile virus.     

密立根油滴实验中运动速度的分析简

通过对带电全程推导分析,而只是选取油滴匀速运动的区域进行测量。通过对带电全程推导分析,得到结果发现油滴在极短时间内就近似达到了极限速度,因此对于匀速区域的选取并不需要特别说明,实验本身的设计是十分合理。