微粗糙结构表面液滴浸润特性的多体耗散粒子动力学研究

超疏水表面因其优异的自洁作用一直是表面科学领域关注的重点.本文使用多体耗散粒子动力学(many-body dissipative particle dynamics, MDPD)方法模拟研究了不同粗糙结构下液滴的浸润特性, 并与Cassie-Baxter理论进行了对比. 研究使用了一种具有长吸短斥作用的流固作用函数来获得不同的液滴浸润性, 并利用一种简洁的数值方法来测量接触角. 模拟结果表明本研究方法能够稳定地捕捉到液滴在粗糙表面的静态和动态特性. 模拟了粗糙结构对三相接触线运动的黏滞作用, 与物理实验结果相符合, 表明Cassie-Baxter理论在实际应用中尚存在一定局限性. 研究分析了在动态铺展过程中的能量转化关系, 并指出在低值表面容易引起液滴反弹.     

Transfer of smectic films to a solid substrate by the method of Maclennan

We investigate monolayers of 2-alcohols (2-C9 to 2-C16) obtained by placing a drop of pure alcohol at the water surface. These alcohols are chiral molecules and we study the racemic mixtures. By ellipsometry and surface tension measurements we are able to characterize the 2D crystallization-melting transition with temperature. We find a first order transition. Using X-ray under grazing incidence we show that the racemic mixture crystallizes at 2D on a hexagonal cell. We find a parity effect on the lateral pressure at the transition and on the stability of the Bragg peak. We compare all results with those observed for 1-alcohols. Received: 11 April 1997 / Revised: 18 August 1997 / Accepted: 9 October 1997     

The lamellar-disorder interface: one-dimensional modulated profiles

We study interfacial behavior of a lamellar (stripe) phase coexisting with a disordered phase. Systematic analytical expansions are obtained for the interfacial profile in the vicinity of a tricritical point. They are characterized by a wide interfacial region involving a large number of lamellae. Our analytical results apply to systems with one dimensional symmetry in true thermodynamical equilibrium and are of relevance to metastable interfaces between lamellar and disordered phases in two and three dimensions. In addition, good agreement is found with numerical minimization schemes of the full free energy functional having the same one dimensional symmetry. The interfacial energy for the lamellar to disordered transition is obtained in accord with mean field scaling laws of tricritical points. Received: 28 March 1997 / Revised: 6 February 1998 / Accepted: 16 February 1998     

二自由度反射式光纤传感探头的结构设计

采用五光纤特殊排列方式,研制了全自动补偿光纤二自由度传感探测器.分析了二自由度的探测方法,给出了可能的结构排列方案.理论上,给出了探测响应函数,与实验结果进行了对比.可用于二自由度非接触测量场合。     

AuBe/p-GaP接触体系界面特性随温度变化的研究

微合金条件对M-S接触的表面与界面特性产生重要的影响.借助光电子能谱分析了AuBe/p-GaP接触体系界面组分变化,用扫描电子显微镜观察其表面形貌；从冶金学观点解析了M-S接触界面反应的特征,并对其温度依赖关系进行了讨论.     

4~20 K 温区固体界面导热填料接触热阻实验研究

超导量子干涉仪、 超导光子探测器等深空探测器需要液氦温区制冷技术提供极低温温度, 固体界面接触热阻的存在会增大耦合界面温度差, 进而增加制冷机系统冷损. 为定量探究4~20 K 深低温区固体接触热阻, 采用GM 作为冷源, 设计了一台可同时调节压力和低温温度的固体界面接触热阻测试实验台. 利用感压纸进行接触界面压力校核, 并对温度重复性进行验证. 实验测试了不同导热介质填充情况下, 温度和压力变化时固体接触热阻的变化规律. 基于最小二乘法对实验数据进行半经验公式拟合, 获得4 ~20 K 温区不同压力加载条件下的接触热阻的定量参考.     

度量算符对Gauss编织态的本征作用及自旋几何

对圈量子引力中标架度量矩阵算符对Gauss编织态的作用为本征作用，提供了完整的证明.求得了全部标架度量矩阵算符的表示矩阵，及其期望值.利用自旋几何定理，在内腿颜色k=0和k=2两种情况下，算得了Gauss编织态顶角毗邻的4条腿(P=1)的相位位形切方向间的全部夹角，以及切矢量的长度. 关键词： 度量算符的表示矩阵 度量期望值 切方向间夹角 切矢量长度     

On the twistor space of a quaternionic contact manifold

In this note, we prove that the CR manifold induced from the canonical parabolic geometry of a quaternionic contact (qc) manifold via a Fefferman-type construction is equivalent to the CR twistor space of the qc manifold defined by O. Biquard.     

A1/Ti/4H-SiC Schottky barrier diodes with inhomogeneous barrier heights

This paper investigates the current-voltage （I-V） characteristics of Al/Ti/4H-SiC Schottky barrier diodes （SBDs） in the temperature range of 77 K-500 K, which shows that Al/Ti/4H SiC SBDs have good rectifying behaviour. An abnormal behaviour, in which the zero bias barrier height decreases while the ideality factor increases with decreasing temperature （T）, has been successfully interpreted by using thermionic emission theory with Gaussian distribution of the barrier heights due to the inhomogeneous barrier height at the A1/Ti/4H-SiC interface. The effective Richardson constant A＊ = 154 A/cm2 . K2 is determined by means of a modified Richardson plot In（I0/T2） - （qσ）2/2（κT）2 versus q/kT, which is very close to the theoretical value 146 A/cm2 · K2.     

Investigation of fill factor losses on 20.2% efficient n‐type mono‐like silicon solar cells with laser contact opening

Large area (243.36 cm²) back‐junction passivated emitter, rear totally diffused (PERT) solar cells with laser contact opening (LCO) on n‐type mono‐like crystalline Si with efficiencies of 20.2% are presented. Boron emitters with high electrical quality (implied open circuit voltage iV_OC up to 700 mV) are formed during a co‐diffusion step using SiO_x:B layers. Increasing the rear metal contact coverage, we observed a decrease in fill factor (FF) instead of the expected increase due to the decrease of the back side series resistance. We show that it can be attributed to recombination centers (RCs) in the space charge region underneath the contact spots inducing an increasing second diode contribution. The presented empirical model for the RCs implemented in Synopsys Sentaurus TCAD allows for a successful reproduction of the FF, pseudo FF and V_OC behaviour with contact coverage. According to this model, the RCs induced by laser ablation and subsequently evaporation of Al have a shallow exponential distribution with a characteristic length of L_T = 0.2 µm and an effective surface density of N *_T0 = 25 cm^–1. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)