温度调控的动态湿度响应褶皱图案

本工作利用光响应温敏聚合物构筑了温控湿度响应褶皱图案,并探索其响应机制与应用.将1-乙烯基-3-蒽甲基氯化咪唑鎓(IMAN)、 N-异丙基丙烯酰胺(NIPAM)与聚乙二醇甲醚甲基丙烯酸酯(OEGMA)三元共聚物P(IMAN-co-NIPAM-co-OEGMA)作为表层,与聚二甲基硅氧烷(PDMS)基底形成双层褶皱体系.蒽基团的光二聚交联能够使体系区域选择性起皱,含NIPAM结构的聚合物链则赋予其温度控制的湿度响应性.在室温、加湿条件下,该褶皱图案消失,其响应机制是聚合物吸湿过程中的模量降低和应力松弛;而在较高温度下,褶皱图案无法由湿度擦除,这是由于顶层聚合物链疏水性增强所导致的.这种同时具有光敏性与温度控制的湿度响应性褶皱图案,在湿度传感、智能显示、智能窗户等领域具有潜在的应用前景.     

Liesegang图案

介绍了Liesegang图案的生长规律、实验研究方法、形成影响因素、理论进展、应用及存在的问题,同时对当前两个活跃的研究方向即复杂Liesegang环和Liesegang图案的微观形成机制进行了讨论.该领域研究的新突破有助于理解自然界中一些复杂图案的形成和控制材料制备中的自组装结构及动物代谢中的结石生长.     

沙子里的图案

文章从物理学家的角度探讨颗粒体系中有序图案的产生和机理,探寻对广泛存在于自然界的非平衡态体系有序结构生成的理解.非平衡态体系的随机扩散与能量耗散的特性是有序结构生成的必备条件,所生成的图形则由这两个因素的权重比值和体系内部的对称性决定.具备以上因素,还需加上最后的一个决定性的关键因素,这就是熵的驱动.熵最大的态决定了体系是有序还是无序的排列.     

图案化锥形氧化锌纳米带的原位热氧化法制备与发光性质

采用光刻技术制备出图案的锌膜,所得锌膜与纯氧在700℃氧化反应10 min,在锌膜的表面上原位生长出具有图案的锥形ZnO纳米带阵列,实现了ZnO纳米带生长位置的可控生长。锌膜上得到的锥形ZnO纳米带为单晶六方纤锌矿结构,长度在1～4μm,纳米带根部和顶部的宽度分别在300～700 nm和100～300 nm。提出了锥形ZnO纳米带的可能生长机理。在波长为300nm光的激发下,发现了锌膜上锥形ZnO纳米带具有发光峰位于395 nm弱的紫外光发光和510 nm强的蓝绿光发光,它们分别起源于ZnO宽带隙的激子发射以及表面上离子化氧空位中的电子与价带中光激发的空穴之间的复合。     

街头那些漂亮的窨井盖

你仔细观察过街头的窨井盖吗?那些大街小巷随处可见的犹如马路补丁的窨井盖,几乎没有人为它们驻足停留。可是,在某些国家,窨井盖成为了一门艺术。日本的窨井盖具有浓郁的文化韵味,最大的特点是独具匠心:每一个县乃至市、区的窨井盖都极具地方特色,独树一帜,别具一格,乡韵浓郁。多以当地的名胜、市花、市树或特产等来构思窨井盖图案,突出本地特色。真是美轮美奂呀!     

Self-Assembly of Gold Nanoparticles on Nanometre-Patterned Surface

The self-assembly processes of gold nanoparticles on nanometre-step-patterned Si surface and polished Si surface are investigated by the convective self-assembly method. The convective self-assembly method is used to deposit the colloids dispersed in benzene onto the substrates. The SEM results show that the configurations of the gold arrays depend on the surface morphology of the substrates. On the nanometre-step-patterned Si surface, the nanoparticles self assemble into parallel lines, and the distance between the neighbouring lines is around 35 nm. On the polished Si surface the nanoparticles form compact domains. In each domain the particles are closepacked in a two-dimensional hexagonal superlattice and are separated by uniform distances. The analysis shows that on the nanometre-step-patterned Si surface, the steps play critical roles in the self-assembly process of gold nanoparticles. The capillary force from the steps drives the particles to lines along the steps. Therefore, the particles tend to self-assemble into one-dimensional line structures when the solvent evaporates. For the polished Si substrate there is a little difference that the particles form two-dimensional hexagonal superlattices without the directional confinement.     

自行车轮辋的力学分析

本文采用有限元法计算自行车轮辋的应力，并进行了实测，理论计算与实验基本一致，可供设计自行车使用。     

简单图案的设计

我们常常还会遇到许多不但设计精美，而且还富有特定含义的图案，如：     

Rhythmic precipitate patterns and fractal structure

Liesegang patterns of parallel precipitate bands are obtained when solutions containing co-precipitate ions interdiffuse in a 1D gel matrix.The sparingly soluble salt formed,displays a beautiful stratification of discs of precipitate perpendicular to the 1D tube axis.The Liesegang structures are analyzed from the viewpoint of their fractal nature.Geometric Liesegang patterns are constructed in conformity with the well-known empirical laws such as the time,band spacing and band width laws.The dependence of the band spacing on the initial concentrations of diffusing(outer)and immobile(inner)electrolytes(A0 and B0,respectively)is taken to follow the Matalon-Packter law.Both mathematical fractal dimensions and box-count dimensions are calculated.The fractal dimension is found to increase with increasing A0 and decreasing B0.We also analyze mosaic patterns with random distribution of crystallites,grown under different conditions than the classical Liesegang gel method,and report on their fractal properties.Finally,complex Liesegang patterns wherein the bands are grouped in multiplets are studied,and it is shown that the fractal nature increases with the multiplicity.