Kinetics of Vesicle Formation and Breakdown

利用停流装置研究了十二烷基硫酸钠(SDS)和十二烷基三甲基溴化铵(DTAB)复配形成囊泡的过程和囊泡破坏过程的动力学性质,并结合动态光散射技术和电子透射显微镜探索囊泡形成和囊泡破坏过程的机理.动态光散射和电子透射显微镜的研究结果表明囊泡的形成过程主要包括四个阶段:混合胶团→柔性的长棒状聚集体→"非平衡囊泡"→平衡囊泡,而与其对应的粒度分散度则呈现"单分散性→多分散性"的周期性变化规律.此外,动力学结果表明囊泡形成过程很长,但其活化能不大,这意味着囊泡形成过程的控制步骤可能不是活化能控制.而相对于囊泡的形成,囊泡的破坏过程是十分迅速的.A combination of stopped-flow,transmission electron microscopy and dynamic light-scattering techniques has been used to study the kinetics of vesicle formation and breakdown as well as the mechanism of vesicle formation and breakdown in DTAB/SDS aqueous solutions.The results show that the process of vesicle formation can be modeled as a sequence of distinct processes:mixed micelles→flexible stick-shaped aggregates→non-equilibrium vesicles→equilibrium vesicle system,and the evolution of particle dispersion degree appears to be a periodical change of "monodispersity→polydispersity".In addition,the kinetic analysis shows that the process of vesicle formation lasts for a long time.However,the activation energy of vesicle formation is not too high,which implies that the control procedure of the process is independent of activation energy.In contrast to the process of vesicle formation,vesicle breakup to mixed micelles appears to be a rapid process.厦门大学科技创新重点项目(No.XMKJCX20052001)资助项目

Progress in Chiral Sensors

手性工程的崛起对简单、经济、快速、实时、在线的手性检测技术提出了挑战。手性传感器是一个重要的发展趋势。本文综述了近年来在手性电化学传感器、基于石英晶体微天平的手性质量化学传感器及手性光学传感器方面的研究进展,重点介绍了各种传感器的制备及其在手性检测中的应用,并展望了该领域的发展前景。The development of chiral engineering requires chiral analytical technologies with simple handling,low cost,high speed,real time and on-line operation.Chiral sensor system represents a major branch of future research.In this paper,the progress in chiral electrochemical sensor,chiral mass chemical sensor based on quartz crystal microbalance and chiral optical sensor is reviewed.The preparations and applications of these chiral sensors are introduced.The prospects of this field are also put forward.福建省自然科学基金项目(No.C0540024);; 福建省教育厅课题(No.JA05301)资

农村留守经历大学生心理行为与人际关系分析

目的探讨农村留守经历大学生(URLB)心理行为特征以及与非URLB心理行为上的差异,为采取干预措施提供依据。方法采用流调中心用抑郁量表、状态特质焦虑问卷、简易应对方式问卷、自尊量表和大学生人际关系综合诊断量表对河北省2所高校的4080名大学生进行问卷调查。结果 URLB大学生负性情绪、积极应对方式、自尊和人际关系与非URLB大学生差异有统计学意义。相关分析表明,URLB大学生负性情绪、消极应对方式与人际关系呈显著正相关,积极应对方式、自尊与人际关系呈显著负相关。回归分析表明,URLB大学生负性情绪、应对方式和自尊对人际关系有显著的预测作用。结论 URLB与非URLB大学生在心理行为上差异有统计学意义,需要对URLB进行适当的心理干预

Kinetics of vesicle formation and breakdown

A combination of stopped-flow, transmission electron microscopy and dynamic light-scattering techniques has been used to study the kinetics of vesicle formation and breakdown as well as the mechanism of vesicle formation and breakdown in DTAB/SDS aqueous solutions. The results show that the process of vesicle formation can be modeled as a sequence of distinct processes: mixed micelles --> flexible stick-shaped aggregates --> non-equilibrium vesicles --> equilibrium vesicle system, and the evolution of particle dispersion degree appears to be a periodical change of "monodispersity --> polydispersity". In addition, the kinetic analysis shows that the process of vesicle formation lasts for a long time. However, the activation energy of vesicle formation is not too high, which implies that the control procedure of the process is independent of activation energy. In contrast to the process of vesicle formation, vesicle breakup to mixed micelles appears to be a rapid process

Chlorofullerenes featuring triple sequentially fused pentagons

通讯作者地址: Tan,YZ(通讯作者),Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 电子邮件地址: [email protected], [email protected] triple sequentially fused pentagons (TSFP) motif is one of the basic subunits that could be used for constructing fullerenes, but it violates the isolated pentagon rule (IPR) and has not been found in carbon cages to date. The properties of TSFP-incorporating fullerenes are thus poorly explored both theoretically and experimentally. Reported herein are four chlorinated derivatives of three different fullerene cages, all with the TSFP motif. X-ray crystallographic analyses indicate that the molecular strain inherent to the pentagon adjacency of a TSFP is significantly relieved upon exohedral chlorination, leaving one of the four pentagon fusion sites unsaturated and rendering the present derivatives chiral. This unique reactivity, in stark contrast to that of previously reported non-IPR fullerenes containing double fused pentagons or triple directly fused pentagons, can be rationalized by density functional theory calculations, and are expected to stimulate further studies of these new members of the fullerene family, both theoretically and experimentally.NNSF of China 20525103,20531050,20721001,20423002 20673088 973 Program 2007CB81530

东北黑土区大豆生产中存在的主要问题、技术需求及发展对策

通过对巴彦县、绥棱县、海伦市、五大连池市和嫩江县的调查,总结了影响东北黑土区大豆生产的关键技术和主要因子,提出了目前大豆生产中的主要问题和技术需求,在此基础上给出了解决对策和发展对策,为大豆的生产提供指导

大豆重迎茬研究展望

通过对大豆重迎茬研究现状与控制减产技术的分析,明确了今后在研究大豆重迎茬工作中的重点,提出控制大豆重迎茬减产的关键技术,为重迎茬种植大豆时提高大豆产量提供科学依据

黄土塬区深剖面土壤水分垂直分布特征 及其时间稳定性

研究土地利用方式对深剖面土壤水分时空动态的影响，对于了解区域水循环在变化 环境下的表现特征具有重要意义．本研究基于长期定位监测数据，对2012 年9 月至2015 年12 月黄土塬区4 种土地利用方式0～15 m 剖面土壤水分状况进行分析．结果表明: 苜蓿草地( ＞7 年) 、休闲地、高产农田和低产农田平均土壤含水量分别为15．1%、22．0%、19．6%和21．1%( 0 ～ 15 m、年度平均值) ; 干湿交替层季节性失水和蓄水分别出现在3&mdash;6 月和7&mdash;10 月，其深度范 围分别为0～2、0～4．6、0 ～ 3 和0 ～ 4．2 m．深层土壤水分具有较好的时间稳定性，其垂直分布受 土地利用方式的影响．观测年份内苜蓿产量和耗水量均呈逐年增加趋势，造成深层土壤的干燥 化程度加大，2～10 m 土层形成稳定土壤干层，阻断了降水补给地下水的途径．对于其他3 种土地 利用方式下的土壤水分平衡，冬小麦生长季农田与休闲地均表现为负平衡; 玉米生长季高产农 田表现为负平衡，而低产农田与休闲地表现为正平衡; 在作物休闲期，农田与休闲地均表现为正 平衡．通过施肥处理所形成的高产农田的作物水分利用效率是低产农田的3 倍以上．</p

MEMS可调谐VCSEL的研究进展

随着全光网络和DWDM系统的发展,MEMS可调谐VCSEL由于其优越的性能,有着相当广泛的应用前景.文章从结构差异上,将近几年来国际上的有关报道分成了单悬臂型,可变形介质模型,半对称腔型和掩埋隧道结型等四类,并对每一类型作了详细的介绍