仿生表面湿空气冷凝析水实验

实验研究了仿生表面与其它四种对比表面上湿空气冷凝析水过程演变.实验中,采用显微CCD动态观察了各表面上冷凝析水过程宏微观演变,分析探讨了各现象物理机制,定量测量了各不同表面的凝集水量,发现仿生表面集水量多于其它四种对比表面.     

Multiple Solutions of Laminar Flow in Channels with a Transverse Magnetic Field

We present a numerical investigation for steady laminar flow of a viscous incompressible electrically conducting fluid through a channel of a rectangular cross-section with a transverse magnetic field and suction or injection wails. Multiple solutions are presented for values of suction Reynolds number R and velocity coefficients of accelerating walls. Additionally, the associated transfer characteristics are discussed in detail.     

具有不同渗透的涨缩管道内微极性流动的同伦分析解

分析了壁面具有不同渗透的涨缩管道内微极性流体的流动．对于壁面的胀缩,考虑常系数和时间函数的膨胀率两种情况．对于第1种情况,应用同伦分析方法得到该问题的速度和微旋转角度的表达式．并且画图分析了各个不同参数,特别是膨胀系数和不同的渗透率对流体的动力特征的影响．可以得到第1个重要的结论:壁面的膨胀率和不同的渗透对流体的动力特征有重要的影响．根据Xu的模型,考虑了第2种也是更具有一般性的情况,假设壁面的膨胀率随时间的变化而变化．在这样的假设下,控制方程被转化成非线性偏微分方程,并且同样也可以应用HAM方法进行求解．应用代数和指数的模型来描述膨胀率从初始状态到最终状态的演变过程．然而,结果表明包含有时间的解很快地趋向于稳态的解．这样可以得到第2个重要的结论,时间在壁面的膨胀收缩中扮演着次要的角色,可以忽略不计．     

Flow of micropolar fluid between two orthogonally moving porous disks

The unsteady,laminar,incompressible,and two-dimensional flow of a micropolar fluid between two orthogonally moving porous coaxial disks is considered.The extension of von Karman’s similarity transformations is used to reduce the governing partial differential equations(PDEs) to a set of non-linear coupled ordinary differential equations(ODEs) in the dimensionless form.The analytical solutions are obtained by employing the homotopy analysis method(HAM).The effects of various physical parameters such as the expansion ratio and the permeability Reynolds number on the velocity fields are discussed in detail.     

DTM-BF method and dual solutions for unsteady MHD flow over permeable shrinking sheet with velocity slip

An unsteady magnetohydrodynamic (MHD) boundary layer flow over a shrinking permeable sheet embedded in a moving viscous electrically conducting fluid is investigated both analytically and numerically. The velocity slip at the solid surface is taken into account in the boundary conditions. A novel analytical method named DTMBF is proposed and used to get the approximate analytical solutions to the nonlinear governing equation along with the boundary conditions at infinity. All analytical results are compared with those obtained by a numerical method. The comparison shows good agreement, which validates the accuracy of the DTM-BF method. Moreover, the existence ranges of the dual solutions and the unique solution for various parameters are obtained. The effects of the velocity slip parameter, the unsteadiness parameter, the magnetic parameter, the suction/injection parameter, and the velocity ratio parameter on the skin friction, the unique velocity, and the dual velocity profiles are explored, respectively.     

应用FTIR确定多孔绝热材料的热辐射参数

本文采用傅里叶变换红外光谱仪(FTIR)确定气凝胶及其复合绝热材料的热辐射物性参数。采用FTIR测量了绝热材料在2.5～25μm光谱范围内的光谱穿透率,进而计算得到质量光谱衰减系数和Rossland平均质量衰减系数。结果表明,绝热材料的光谱衰减系数具有很强的光谱依赖性,被测材料的Rossland平均衰减系数随温度的升高而降低。被测材料的辐射导热系数几乎与温度的立方呈正比,并随着密度的增大而降低。     

Falkner-Skan方程的近似解析解

研究了粘性流体绕流楔型物体的Falkner-Skan边界层方程求解问题.利用Adomian拆分方法,通过引入Crocco变量变换将无穷区间的边界值问题转为初值问题并利用Padé逼近技巧确定初值,给出了一种有效的解析分解方法.进一步,本文设计了一种数值解法,将本文得到的近似解析解及数值结果与早期研究者Hartree等人的结果进行了比较,证明了本文提出的解法的有效性和可靠性.     

苯乙烯基噻吩单体及对应的聚脲烷的合成 及其非线性光学性能

一种新型的反式-7-［4-N,N-二(β-羟基乙基胺基苯)］-3,5-二硝基乙烯基-噻吩（HBDT）单体分子及对应的预聚物和聚脲烷被合成和表征.由于噻吩环的电子去局域化能量低于苯环,在受授有机共轭化合物中噻吩环比苯环表现出更有效的共轭和更高的非线性,同时也能使目标分子保持好的光、热稳定性.该单体分子及其对应的聚脲烷在普通有机溶剂中具有良好的可溶性,聚脲烷膜具有好的热稳定性.制备了高质量的聚脲烷膜并进行了电晕极化.单体在甲醇中的紫外可见吸收峰（530nm）与对应未经电晕极化聚脲烷膜的吸收峰基本上没有改变.通过溶剂变色法及简并四波混频（DFWM）法测试了单体的二阶和三阶非线性极化率,其β     

纳米组装相变储热材料的热设计前沿

本文简单回顾了固液相变储热材料发展历程,重点针对纳米多孔定形相变材料,从材料层面的研发设计,到热物理层面的微观限域空间负载、结晶、导热机理,乃至围绕异相/异质匹配提出的显著提升相变蓄传热性能的强化手段进行了总结.同时,指出了目前受制于单一尺度孔径无法兼顾储释热的密度和速率的现状,并探讨在此基础上借助新型多级尺度孔径的骨架材料以突破瓶颈的可能.最后,系统梳理了与之伴随的一系列亟待解决的科学问题、机遇和挑战.