摘要：局部电荷的强离域和强偶极矩是影响共价有机框架(COFs)基光催化剂催化析氢性能的两个关键因素.然而,基于精确的调控结构模型来系统研究这种构效关系的报告相对较少.本研究提出了一种新的策略,通过合理的设计,制备了三种三芴酮基COFs,通过在分子水平上调控单体的结构和偶极来提高局部电荷离域指数.我们重点研究这三种三芴酮基COF的局部电荷离域与光催化性能之间的构效关系.在不同三芴酮基COF中,1,3,5-三(对甲酰基苯基)苯基COF(TeTpb-COF)展现出21.6 mmol g^(-1)h^(-1)的最高析氢速率,与2,4,6-三(4-醛基苯基)-1,3,5-三嗪基COF(TeTt-COF,0.2mmol g^(-1)h^(-1))相比,光催化析氢性能提高了108倍.这种性能的增强可归因于其强大的分子内置电场提高了供体-受体嵌段单元中光生电荷的有效分离效率.这项工作证实了调整构建块可以极大增强三芴酮基COFs中的局部偶极矩,从而显著改善光催化析氢性能.构建模块的调控策略为创建高效的新型COF基光催化析氢平台提供了新机会.

摘要：The study of the movement behavior of geckos on a vertical surface, including the measurement and recording of the reaction forces as they move in different directions, plays an important role in understanding the mechanics of the animals' locomotion. This study provides inspiration for the design of a control system for a bionics robot. The three-dimensional reaction forces of vertical surface-climbing geckos (Gekko gecko) were measured using a three-dimensional force-sensors-array. The behavior of gecko as it moved on a vertical surface was recorded with a high speed camera at 215 fps and the function of each foot of a gecko are discussed in this paper. The results showed that the gecko increased its velocity of movement mainly by increasing the stride frequency in the upward, downward and leftward direction and that the speed had no significant relationship to the attachment and detachment times. The feet above the center-of-mass play a key role in supporting the body, driving locomotion and balancing overturning etc. The movement behavior and foot function of geckos change correspondingly for different conditions, which results in safe and effective free vertical locomotion. This research will be helpful in designing gecko-like robots including the selection of gait planning and its control.

摘要：作物的生长冗余,也就是营养器官的过度生长,常常对作物产量不利,因此被称为作物的‘公地悲剧’。作物品种内相邻植株之间的资源竞争也会导致可塑性的营养器官的过度生长,因此被称为可塑性的公地悲剧。然而,目前有关这种可塑性的公地悲剧如何响应不同作物品种和不同的资源水平的研究较少。本研究设计了盆栽实验来探索这一问题。为设置根系竞争和无竞争两种处理,把同品种两个植株栽种在同一花盆中,分别用尼龙和塑料进行隔离;采用了两个小麦品种(古老品种和尚头和现代品种92-46),设置了两个资源水平处理。研究结果表明,与92-46相比,和尚头品种把资源更多地分配给茎叶,更少地分配给种子。异速生长数据显示,在24对尼龙隔离和塑料隔离处理的比较中,只有4对显示出程度很小的差异。异速生长数据还显示,相比和尚头品种,92-46品种对增加资源的响应程度更小。基于有限样本大小,本研究揭示了作物地上部分营养生长和繁殖生长之间的权衡关系。正是这种权衡关系,导致了和尚头小麦品种的‘公地悲剧’式生长,同时也使得92-46小麦品种的种子产量得以提升。小麦的公地悲剧更可能是源自遗传性状(比如古老品种的生长冗余),而不太可能是源自植株的可塑性冗余生长。现代小麦品种92-46可能采用了节约型的资源利用方式,而古老品种则采取的是消耗型策略。综上所述,本研究表明育种工作者应当选育个体竞争力低的基因型。

摘要：New thiazolo[4,5-d]pyrimidines 4a, b, thioxopropanoic acid ethyl ester 7 and 4-oxothiazolidine benzenesulfonamides 9a-h were designed and synthesized. The molecular design was performed using MOE (Molecular Operating Environment) software to predict the binding mode of the proposed compounds on hCA II. All the newly synthesized compounds were evaluated for their in-vitro anticancer activity against liver cancer cell line (HEPG-2) in which hCAII is overexpressed. The activity of the screened compounds was compared with that of doxorubicin, the reference drug. The radiosensitizing ability of the promising compounds 3, 4b, 9b was studied which showed an increase in the cell killing effect of γ-radiation after combination with them.

摘要：The majority of marine microbes remain uncultured,which hinders the identification and mining of CO_(2)-fixing genes,pathways,and chassis from the ***,we investigated CO_(2)-fixing microbes in seawater from the euphotic zone of the Yellow Sea of China by detecting and tracking their ^(13)C-bicarbonate(^(13)C-HCO_(3)^(-))intake via single-cell Raman spectra(SCRS)*** target cells were then isolated by Raman-activated Gravity-driven Encapsulation(RAGE),and their genomes were amplified and sequenced at one-cell *** single-cell metabolism,phenotype and genome are *** identified a notyet-cultured Pelagibacter spp.,which actively assimilates ^(13)C-HCO_(3)^(-),and also possesses most of the genes encoding enzymes of the Calvin-Benson cycle for CO_(2) fixation,a complete gene set for a rhodopsin-based light-harvesting system,and the full genes necessary for carotenoid *** four proteorhodopsin(PR)genes identified in the Pelagibacter *** confirmed by heterologous expression in *** results suggest that hitherto uncultured Pelagibacter *** light-powered metabolism to contribute to global carbon cycling.

摘要：太阳能驱动光催化分解水制氢是实现可持续制氢气的一种有效策略.硫化镉半导体光催化剂基于其较强的可见光响应、适宜的氧化还原反应带边位置以及优异的电荷传输性能而备受关注.本文综述了近年来国内外在提高硫化镉基光催化剂制氢性能的设计、改性和制备等方面的研究进展.首先简要介绍了光催化制氢的基本概念和机理,阐述了硫化镉光催化制氢的基本性质、重要进展和瓶颈,综述了该材料的发展前景.随后,重点讨论了硫化镉基光催化剂光催化分解水产氢的各种改性策略,其中有效的策略是产生更多的载流子,促进电荷的有效分离,促进界面电荷转移,加速电荷利用,以及抑制电荷诱导的自光腐蚀.针对每一种改性策略,都详细讨论了影响光催化剂性能的重要因素和未来潜在的研究方向.最后介绍了纳米结构硫化镉和硫化镉基纳米复合材料在光催化分解水产氢中的发展前景和面临的挑战.本综述将为开发镉基半导体光催化剂提供重要和及时的理论指导,并促进其在太阳能氢气生产中的应用.