多自由度振动系统的一类凸集响应

对激励用凸集合建模的线性时不变振动系统定义了响应集的概念，将多自由度振动系统的凸集响应问题转化成寻求响应集的问题，从而降低了求解的难度．并提出了求解一类凸集载荷的响应集的支撑超平面法．对有限时刻的响应集，导出了求任意方向边界点的解析解，而对无限时刻的响应集，建议了一种求任意精度的凸多胞形近似的方法．最后给出了一个实例，得到了不同时刻的响应集，并将凸集响应与谐波响应及非平稳随机响应作了对照     

Subharmonic bifurcations and chaotic dynamics of an air damping completely inelastic bouncing ball

We investigate the dynamics of a plastic ball on a vibrated platform in air by introducing air damping effect into the completely inelastic bouncing ball model. The air damping gives rise to larger saddle-node bifurcation points and a chaos confirmed by the largest Lyapunov exponent of a one-dimensional discrete mapping. The calculated bifurcation point distribution shows that the periodic motion of the ball is suppressed and a chaos emerges earlier for an increasing air damping. When the reset mechanism and the linear stability which cause periodic motion of the ball both collapse, the investigated system is fully chaotic.     

基于模糊分类的图像颜色直方图研究

从视觉感知特性出发，针对基本颜色直方图中区间刚性划分造成的与人类对相似颜色心理认知的不匹配问题．提出一种基于模糊分类统计的改良直方图，依次介绍该方法的基本思想、模糊直方图算法、实验分析和小结。     

Some Properties of Regular and α-Regular （LM）-Spaces

In this paper, we give some properties of regular (LM)-spaces and α-regular (LM)-spaces and investigate the relationship among them.     

准齐性算子族的共鸣定理

本文给出了值域空间为有序拓扑向量空间的准齐性算子族的几个共鸣定理.     

Extended structural materials constructed from sulfate-centered Preyssler-type polyoxometalate with excellent electrocatalytic property

The sulfate-centered Preyssler-type polyoxometalate was firstly used to construct inorganic-organic hybrid materials, which exhibits excellent electrocatalytic activity toward reduction of H₂O₂ and NO₂^-.     

Rhodium‐Catalyzed Regioselective Hydroxylation of Cage B−H Bonds of o‐Carboranes with O2 or Air

A rhodium‐catalyzed hydroxylation of a cage B4?H bond in o‐carboranes with either O₂ or air as the oxygen source is described, and serves as a new methodology for the regioselective generation of a series of 4‐OH‐o‐carboranes in a one‐pot process. The use of either O₂ or air as both the oxidant and the oxygen source makes this protocol very environmentally friendly and practical.     

Sponge-inspired multisensory hydrogel

The preparation of smart sensors with multiple sensory systems, reusable property, and high sensitivity remains a challenge. Here, inspired by a sponge, we develop a multisensory PCA–poly(vinyl alcohol) (PVA)/borax–LiCl hydrogel (named PPL hydrogel) with low cost and simple fabrication process using sodium polyacrylate (PAAS), PVA, and lithium chloride (LiCl) to address this challenge. PPL hydrogel has a sponge-like porous structure and can repeatedly “absorb” and “drain” water, while maintaining good tensile (strain up to 1442%) and electrical conductivity. PAAS builds the main skeleton of PPL hydrogels and provides the basis for building the pore structure, PVA enhances the mechanical properties of the crosslinked network, while LiCl ionic solution further improves the conductivity, which can reach 8.8 s m⁻¹ and be increased nearly 42 times better than without LiCl. Therefore, this makes PPL hydrogel a very sensitive sensing system for wearable devices that can be used to detect signals from the human body. Additionally, PPL hydrogel is also capable of detecting temperature due to its temperature-sensitive properties. Moreover, PPL hydrogel can also roughly identify the basic properties of different solvents. Our simple, low-cost and multisensory PPL hydrogel offers promising opportunities for multisensory sensors, even functional/smart materials, flexible/wearable devices, and medical care.