Effect of lengthening alkyl spacer on hydroformylation performance of tethered-phosphine modified Rh/SiO_2 catalyst

Rh/SiO2 catalysts with tethered-phosphines with different alkyl spacer lengths have been prepared,tested and characterized.Lengthening the alkyl spacer of the tethered-phosphine improved the flexibility of tethered-phospine,promoted the formation of active species and enhanced the activity of hydroformylation over other tethered-phosphine modified Rh/SiO2 catalysts.

悬臂型阳离子水性聚氨酯分散体的合成

以2-乙基-2-羟甲基氧杂环丁烷与二甲胺为原料,合成了一种亲水离子位于聚氨酯结构的侧链、且结构中不含有β氢的阳离子亲水扩链剂--N,N-二甲基-2-(二羟甲基)丁胺(DMDMOBA),将其作为扩链剂合成了阳离子水性聚氨酯。采用1H NMR和液质联用对N,N-二甲基-2-(二羟甲基)丁胺进行结构表征,采用马尔文激光粒度仪对阳离子水性聚氨酯乳液的粒径进行测试,采用拉伸试验机对聚氨酯胶膜拉伸强度进行测试。结果表明:与常用阳离子亲水扩链剂N-甲基二乙醇胺(MDEA)比较,新型扩链剂合成的阳离子水性聚氨酯的亲水离子位于聚氨酯侧链,其自乳化能力好于主链型阳离子水性聚氨酯,且具有更好的抗黄变性能,合成的水性聚氨酯胶膜力学性能也优于主链型阳离子水性聚氨酯。

Dynamical Interaction Between Information and Disease Spreading in Populations of Moving Agents

Considering dynamical disease spreading network consisting of moving individuals,a new double-layer network is constructed,one where the information dissemination process takes place and the other where the dynamics of disease spreading evolves.On the basis of Markov chains theory,a new model characterizing the coupled dynamics between information dissemination and disease spreading in populations of moving agents is established and corresponding state probability equations are formulated to describe the probability in each state of every node at each moment.Monte Carlo simulations are performed to characterize the interaction process between information and disease spreading and investigate factors that influence spreading dynamics.Simulation results show that the increasing of information transmission rate can reduce the scale of disease spreading in some degree.Shortening infection period and strengthening consciousness for self-protection by decreasing individual’s scope of activity both can effectively reduce the final refractory density for the disease but have less effect on the information dissemination.In addition,the increasing of vaccination rate or decreasing of long-range travel can also reduce the scale of disease spreading.

倍半硅氧烷基电致发光材料的研究进展

有机电致发光器件(OLED)作为一种新型显示器件,其结构简单、易于制造、成本更低、性能更好,未来在各领域将有很大的应用潜力。其中电致发光材料是OLED的核心材料,是OLED能否工业化生产的关键因素,但目前发光材料仍存在一些不足。多面体倍半硅氧烷(POSS)作为一种笼状无机材料,由于具有良好的耐热性、力学强度、稀释效应,经常与咔唑、芴等有机物杂化,从而有效地改善光电和物理性能,被用作OLED电致发光材料,已得到当前电致发光研发领域的极大关注。本文主要介绍了倍半硅氧烷基电致发光材料的研究进展。

约束环境下的多移动机器人自适应伸展算法(英文)

本文介绍了一种用来控制移动机器人组成链式网络并修复通讯连接的自适应分布式机器人合作算法。开发了单层链式伸展算法和双层链式伸展算法,使得移动机器人可以对开放式环境和受约束环境进行探索。还介绍了一种用于寻找最优通讯距离的综合化的方法。通过使用其测量结果,移动机器人系统可以组织成为优化的链式结构并进行伸展。这种伸展算法可以检测到网络中某个机器人节点的缺失,并重新配置系统。它为通讯连接的中断问题提供了一种自适应的解决方案。