Competition Between Interfacial Interaction and Microphase Separation in Crystallization of Filled Block Copolymers

Understanding the effect of repulsive interaction between blocks on crystallization in block copolymers is beneficial for the design and development of sophisticated nanostructures. Dynamic Monte Carlo simulations were performed to reveal the crystallization mechanism of block copolymers containing one‐dimensional nanofiller under different repulsive interaction strengths between crystallizable and noncrystallizable blocks. During crystallization, crystalline morphology is determined by the competition between segmental orientation perpendicular to microphase interfaces dominated by microphase separation and that along the direction of the long axis of the nanofiller controlled by interfacial interaction. As the repulsive interaction between different blocks is strengthened, the competition between microphase separation and interfacial interaction is intensified, eventually leading to an increase in crystallization rate and a degradation in crystalline morphology. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1516–1526     

含钼碱性电解液中乙醇在铂黑电极上氧化循环伏安曲线的2,3,5周期及非周期振荡

中图分类号Ｏ６５７·１４文献标识码Ａ通常乙醇在铂黑电极上氧化的循环伏安曲线在经过开始的一段过渡期后会变得稳定，但在特定的条件下也会出现不稳定的振荡现象〔１～５〕．由于钼的存在可以促进有机小分子氧化过程中强吸附物种的氧化，降低过电位〔６〕，因此我们设想...     

光交联自支撑丝素蛋白水凝胶的三维快速成型

将丝素蛋白(SF)光诱导自交联原理与挤出式三维(3D)打印相结合, 开发了光交联自支撑SF水凝胶的原位成型加工技术. 采用旋转流变仪、 光流变测试系统和改装的挤出式3D打印设备等对SF溶液的流变性能、 光交联性能和成型加工性能等进行研究. 结果表明, SF溶液主要表现为黏性特征, 结构强度和稳定性均较差. 利用SF的光诱导自交联特性, 以三联吡啶氯化钌[Ru(Ⅱ)]和过硫酸钾(KPS)为蓝光引发体系, 可实现SF水凝胶的快速光交联成型. SF光交联行为符合指数函数增长模型, 因“滤镜效应”, 当Ru(Ⅱ)的浓度为0.05 mmol/L时, SF具有最佳的光交联性能. 通过调节气压、 针头孔径、 移动速度及固化速率等参数, 采用3D打印设备可实现从单层几何结构到多层三维网络构型SF凝胶材料的高效、 精准构建, 为SF的生物3D打印提供了新思路.     

Chemical‐Template Synthesis of Micro/Nanoscale Magnesium Silicate Hollow Spheres for Waste‐Water Treatment

Micro/nanoscale magnesium silicate hollow spheres were synthesized by using silica colloidal spheres as a chemical template in one pot. The hollow spherical structure, consisting of well‐separated nanoscale units, was microscale as a whole and could be easily handled in solution. The as‐synthesized magnesium silicate hollow spheres with large specific surface area showed availability for the removal of organic and heavy‐metal ions efficiently from waste water. Importantly, the micro/nanoscale magnesium silicate hollow spheres that had adsorbed organic pollutants could be regenerated by calcination and used repeatedly in pollutant removal. Magnesium silicate hollow spheres synthesized by a scaled‐up chemical template method may have potential applications in removing cationic dyes and heavy‐metal ions from waste water.     

Highly Sensitive Determination of microRNA Using Target‐Primed and Branched Rolling‐Circle Amplification

One‐nucleotide differences in microRNAs (miRNAs) can be discriminated in an assay based on a branched rolling‐circle amplification (BRCA) reaction and fluorescence quantification. With the proposed method miRNA can be detected at concentrations as low as 10 fM , and the miRNA in a total RNA sample of a few nanograms can be determined.

     

Note on the m-step competition numbers of paths and cycles

Since Cohen introduced the competition graph in 1968, the competition graph has been studied widely and many variations of it have been discussed. In 2000, Cho, Kim and Nam defined and studied the m-step competition graph and computed the 2-step competition numbers of paths and cycles. Recently, Ho gave bounds for the m-step competition numbers of paths and cycles. In this paper we continue to study the m-step competition numbers of paths and cycles, partially improve the results of Ho on the upper bounds of the m-step competition numbers of paths and cycles, and show that a conjecture posed by Ho is not true.     

Novel butterfly pyrene-based organic semiconductors for field effect transistors

Novel butterfly pyrene derivatives functionalized with trifluoromethylphenyl and thienyl aromatic groups in the 1-, 3-, 6- and 8-positions of pyrene cores and have been synthesized by Suzuki coupling reactions, and their crystal structures, optical and electrochemical properties investigated; additionally, the field effect transistor using as the active material exhibited a p-type performance.     

Fluorescent "light-up" bioprobes based on tetraphenylethylene derivatives with aggregation-induced emission characteristics

Aggregation in poor solvents and complexation with calf thymus DNA and bovine serum albumin turn "on" the fluorescence of tetraphenylethylene derivatives, due to the restriction of intra-molecular rotations of the dyes in the aggregates and complexes.     

The Dirichlet problem of higher order quasilinear elliptic equation

The paper is concerned with the Dirichlet problem of higher order quasilinear elliptic equation: