一种可调的Catmull-Clark细分曲面

通过在曲面细分过程中引入一个参数t(0≤t≤1)，使得Catmull-Clark细分曲面可调，得出一种新的算法。这种算法简单直观，通过调节参数t值，可以得到一族细分曲面。该族细分曲面不但保留了许多Catmull—Clark细分曲面的特性，而又可以方便地解决在工程中经常遇到的调整曲面位置和形状的问题。同时，还可以将这种细分算法作为Catmull-Clark细分的前置处理方法。文中详细讨论了这一算法，并给出了验证实例。     

基于Catmull-Clark细分规则的双参数细分曲面

通过在曲面细分过程中引入两个参数,给出一种新的细分曲面构造的算法,使得所得的细分曲面可调.通过调节一个参数值,可以得到一族细分曲面.另一个参数是细分过程的改变参数,改变它的初值,也可得细分结果.最后给出了曲面设计的实例,表明这种算法简单、有效.     

Gecko‐Inspired Surfaces: A Path to Strong and Reversible Dry Adhesives

The amazing adhesion of gecko pads to almost any kind of surfaces has inspired a very active research direction over the last decade: the investigation of how geckos achieve this feat and how this knowledge can be turned into new strategies to reversibly join surfaces. This article reviews the fabrication approaches used so far for the creation of micro‐ and nanostructured fibrillar surfaces with adhesive properties. In the light of the pertinent contact mechanics, the adhesive properties are presented and discussed. The decisive design parameters are fiber radius and aspect ratio, tilt angle, hierarchical arrangement and the effect of the backing layer. Also first responsive systems that allow thermal switching between nonadhesive and adhesive states are described. These structures show a high potential of application, providing the remaining issues of robustness, reliability, and large‐area manufacture can be solved.     

Charge migration on hydrophobic and hydrophilic silicon dioxide

Experimental results are presented which shed light on the properties of thin discontinuous metal films as chemical sensing elements. They demonstrate further some interesting differences between hydrophilic and hydrophobic sensing structures. Two different methods are used to study the migration of charges out onto the oxide surface outside the metal gate of metal–oxide–semiconductor capacitors after treatment of the surface with hydrochloric acid. The charge migration is observed either as a time dependent increase of the inversion capacitance or as a possibility to generate a photocapacitive current by a chopped light beam hitting the oxide surface at a distance from the contact. It is concluded that the charge migration occurs only if the surface was hydrophilic before the HCl-treatment. For a hydrophobic surface neither the inversion capacitance nor the photocapacitive current changed upon ion-treatment. An explanation for an observed increase of the capacitance level of hydrophilic structures immersed in electrolytes is also given.     

磁流变抛光高精度光学表面中的工艺参数

对磁流变抛光进行高精度光学表面加工中必须考虑和控制的7类参数,即磁流变液黏度、磁场强度、磁流变液流量、抛光轮转速、锻带厚度、切深以及抛光斑点特性进行分析和优化,得出单因素条件下材料的去除量总是同这7类参数的变化存在一定的内在联系．在分析和优化磁流变抛光过程中这些参数的基础上,采用自研的KDMRF-1000机床对一块K4材料口径100mm的平面镜进行了抛光加工实验．经过两次循环大约200min的抛光后．面形误差值由最初的峰谷值（PV）为262nm,均方根值（RMS）为49nm收敛到最终的PV为55nm,RMS为5．7nm实验中面形误差的收敛表明：只要掌握了磁流变抛光过程中的这7种参数的变化规律,就能充分利用磁流变抛光技术,为高精度光学表面的加工提供可靠的保障．     

用偏微分方程构造过渡面

用偏微分方程的构造曲面是一种新兴的方法，本文借若干算例说明如何用偏微分方程构造两已知曲面之间的过渡面。论文着重讨论用四阶方程构造一阶连续的过渡面。     

Light‐Induced Contraction/Expansion of 1D Photoswitchable Metallopolymer Monitored at the Solid–Liquid Interface

The use of a bottom‐up approach to the fabrication of nanopatterned functional surfaces, which are capable to respond to external stimuli, is of great current interest. Herein, the preparation of light‐responsive, linear supramolecular metallopolymers constituted by the ideally infinite repetition of a ditopic ligand bearing an azoaryl moiety and Co(II) coordination nodes is described. The supramolecular polymerization process is followed by optical spectroscopy in dimethylformamide solution. Noteworthy, a submolecularly resolved scanning tunneling microscopy (STM) study of the in situ reversible trans‐to‐cis photoisomerization of a photoswitchable metallopolymer that self‐assembles into 2D crystalline patterns onto a highly oriented pyrolytic graphite surface is achieved for the first time. The STM analysis of the nanopatterned surfaces is corroborated by modeling the physisorbed species onto a graphene slab before and after irradiation by means of density functional theory calculation. Significantly, switching of the monolayers consisting of supramolecular Co(II) metallopolymer bearing trans‐azoaryl units to a novel pattern based on cis isomers can be triggered by UV light and reversed back to the trans conformer by using visible light, thereby restoring the trans‐based supramolecular 2D packing. These findings represent a step forward toward the design and preparation of photoresponsive “smart” surfaces organized with an atomic precision.