We find that i ) with the increase of the long - range interaction , the interfacial coupling and the thickness of one period , the phase transition temperature of the ferroelectric superlartice increases 我们发现,随着长程相互作用和界面耦合作用的增强以及铁电超晶格尺寸的增大,整个材料的相变温度升高。
A one - - dimensional photonic crysta1 ( l - - d pc ) model is developed and used to calculate the energy band structures of 1 - - d pc and 1 - - d pc su - per1attice ( sl ) based on fdtd method 采用该方法研究了一维光子晶体及一维光子晶体超晶格的能带结构。计算了一维光子晶体及一维光子晶体超晶格的透射(反射)谱。
Experimentally , an interesting six - route ndr characteristic , resulting from the form of split miniband structures and the extension of high - field domain in the superlattice , is observed at room temperature 实验的结果显示,由于此分?迷你带结构及超晶格结构中高场区域的扩展,于常温下可观察出?道轨迹之多重负微分电阻特性。
The thermal conductivity of superlattice films was studied using an equilibrium molecular dynamics simulation method , and the thermal conductivity of two materials composing the superlattice was calculated respectively 摘要采用非平衡态分子动力学方法模拟了超晶格薄膜的热传导性能,分别计算了组成超晶格薄膜的两种材料的导热系数。
The effects of the interfacial coupling and the thickness of one period on the pyroelectric properties of the superlartice are investigated by taking into account the long - range interaction 研究了长程相互作用对铁电超晶格热电性质的影响,并在考虑了长程相互作用的情况下,分别研究了界面耦合和尺寸效应对铁电超晶格热电性质的影响。
In particular , we were investigating how the thickness of the layers determined whether the superlattice behaved as a metal , with low electrical resistance , or as an insulator , with high resistance 我们已经知道这种超晶格的电性非常有趣,那时我们特别想了解的,是材料层的厚度变化如何让超晶格成为金属(低电阻)或绝缘体(高电阻) 。
In this thesis , the main contents are following : 1 . reviewing the theory of nonlinear frequency conversion . quasi - phase - matching is discused . presenting the method for configuring periodically poled as well as multiple period superlattice 阐述了非线性频率变换的原理,讨论了相位匹配和准相位匹配技术,着重说明了周期和准周期光学超晶格的工作原理。
Bias voltage , which are related to the superlattice structural paraments , the doped densities and the applied bias voltage . we have also investigated the characteristics of superlattice under hydrostatic pressure by simulations 超晶格的负微分电导区还导致出现固定偏压下随时间变化的电流自维持振荡,振荡产生的条件依赖于其结构参数,掺杂浓度和外加偏压的大小。
For problems of vertical transport in the superlattice at fixed d . c . bias voltage , ode45 is optional . for problems of vertical transport in the superlattice with the increasing bias voltage and the relatively higher doped densities , ode15s is optional 针对较高难度问题,即研究偏压从零线性上升而且掺杂参数v较大时的超晶格纵向输运问题( du / dt ( 0 ) ,一般首选ode15s 。
Thirdly we introduce the superlattice model with alternating site energies which is more complicated than the simple tight - binding model , and moreover we explore the influence of the alternating diagonal term in hamiltonian on the quasi - energy bands and dynamics 接着引入更为复杂的格点能交替变化的超晶格模型,并在此基础上考察了hamiltonian中交替变化的对角项对准能谱与动力学的影响。