耐酸型磺化酚酞侧基聚芳醚砜/氨基化石墨烯杂化膜及渗透汽化醋酸脱水性能

将四乙烯五胺修饰的氨基化石墨烯(reduced graphene oxide modified by tetraethylene pentamine, rGO-TEPA)引入磺化酚酞侧基聚芳醚砜(sulfonated polyarylethersulfone with cardo, SPES-C)中制备了不同填充量的SPES-C/rGO-TEPA杂化膜,并用于醋酸的渗透汽化脱水。采用扫描电镜(scanning electron microscope, SEM),热重分析(thermogravimetric analyzer, TGA)和水接触角测试对杂化膜进行了表征,考察了杂化膜的溶胀行为,吸附和扩散选择性及分离性能。结果表明:rGO-TEPA在膜内分散均匀,杂化膜表面无缺陷。杂化膜热稳定性优良。rGO-TEPA的引入提高了膜的亲水性和溶胀度。料液温度为50℃时, rGO-TEPA填充量为4%的杂化膜M-4综合分离性能最优,渗透通量和分离因子分别达到0.765 kg/(m~2·h)和96.5。15 d的长期测试和拉伸实验结果证明所得杂化膜具有良好的稳定性和耐酸性能。     

Blend Concepts for Fuel Cell Membranes

Direct methanol fuel cells （DMFC） are an alternative to lithium ion batteries as energy supply for mobile applications such as laptops, PDA＇s and cellphones. It would be advantageous if pure or highly concentrated methanol could be used as the fuel in these DMFC, due to the high energy density of meOH. However, most of the ionomer membranes used up to now as proton conductor in DMFC can not withstand pure or highly concentrated methanol due to extreme swelling or even dissolution under these conditions. Therefore it is required to prepare H^＋ -conducting membranes which remain dimensionally stable in pure or highly concentrated methanol. One way to approach this goal is to cross-link the ionomer membranes so that the swelling under the desired methanol-rich conditions is limited.     

半互穿网络法制备有机/无机杂化阴离子交换膜

以1,2-双(三乙氧基硅基)乙烷杂化改性的聚乙烯醇(PVA)为聚合物基底,以溴化聚乙烯亚胺(BPEI)为阳离子聚电解质,采用半互穿网络法制备新型阴离子交换膜.对含水率、离子交换容量及膜的形态进行了考察,并测试了膜的电导率及甲醇渗透率以研究其在直接甲醇燃料电池中的应用.测试结果表明,BPEI质量分数在40％时,PVA与BPEI互容性较好,无明显相分离现象产生.BPEI质量分数为20％的阴离子交换膜具有较好的综合性能,其在30℃下的电导率和甲醇渗透率分别为1.32×10-2 S/cm和7.88×10-7 cm-2·s-1.     

Lipopeptaibols, a novel family of membrane active, antimicrobial peptides

Lipopeptaibols are members of a novel group of naturally occurring, short peptides with antimicrobial activity, characterized by a lipophilic acyl chain at the N-terminus, a high content of the turn/helix forming α-aminoisobutyric acid and a 1,2-amino alcohol at the C-terminus. The amino acid sequences range from 6 to 10 residues and the fatty acyl moieties from 8 to 15 carbon atoms. The peptide portion of lipopeptaibols can be shorter than those of the nonlipidated peptaibols that range from 10 to 19 amino acid residues. The longest peptides fold into a mixed 3₁₀/α helix, whereas the shortest peptides tend to adopt a β-turn/sheet structure. Using solution methodologies, a series of analogues of trichogin GA IV was synthesized which allowed determination of the minimal lipid chain and peptide main-chain lengths for the onset of membrane activity and exploitation of a number of spectroscopic techniques aimed at determining its preferred conformation under a variety of conditions and investigating in detail its mode of interaction with, and its effect on, the phospholipid membranes. Received 26 January 2001; received after revision 7 March 2001; accepted 15 March 2001     

荷电镶嵌膜的研究进展

荷电镶嵌膜主要用于无机盐与低分子量有机物的分离。本文简要介绍了荷电镶嵌膜及其制备原理、近二十年来荷电镶嵌膜的研究进展和发展动态。荷电镶嵌膜的制造主要有嵌段共聚、接枝改性、界面聚合、共混等方法。荷电镶嵌膜的研究热点主要集中在提高荷电镶嵌膜的荷电容量、控制膜内正负荷电基团的比例、深化研究荷电镶嵌膜的传递机理、表征技术和工业应用等方面。     

微乳液膜分离活性染料的传质动力学研究

通过恒界面池方法对微乳液膜提取活性染料的传质动力学进行研究,推导了其在表观动力学方程中各浓度项的级数值,得到其反应速率常数及反应活化能.以烷基苯酚环氧乙烷缩合物(OP-7)为表面活性剂、异戊醇为助表面活性剂、煤油作为油溶剂、三烷基胺(N235)为促进迁移载体,NaOH溶液作为内水相构成微乳液膜体系,其提取艳蓝KNR染料废水的传质实验结果表明,在乳水体积比为1∶15,废水相质量浓度在5000mg·L-1的条件下艳蓝KNR的提取率可达99%以上.     

Increase in electron transfer activity in photosystem Ⅱ of spinach thylakoids caused by conversion of phosphatidyl- glycerol to phosphatidic acid molecules

The techniques of oxygen electrode polarography, sodium dodecyl sulfate-polyacryamide gel electrophoresis (SDS-PAGE) and thin layer chromatography (TLC) were employed to investigate the effect of phospholipase D treatment on physiological function of spinach thylakoids. It was shown that the phospholipase D treatment on thylakoid resuited in the degradation of phosphatidylglycerol (PG) and occurrence of phosphatidic acid (PA). The changes of PG to PA molecules caused an increase in oxygen evolution in photosystem Ⅱ (PS Ⅱ), which was accompanied by an uncoupling effect on thylakoid membrane. It was revealed that the head-groups of PG molecules play an important role in themaintenance of the appropriate physiological activity of thylakoid membrane.     

高压静电场对植物细胞跨膜电位的影响及机理初探

采有平面类脂双层模型分析外加高压静电场对植物细胞跨膜电位的影响，并探讨其微观机理。在生物学基础上，结合能斯特公式及隧道效应导出外加高压静电场与跨膜电位的关系，可以解释相关的实验结果。     

膨体聚四氟乙烯膜气体透过行为的研究

文中利用具有不同结构参数的膨体聚四氟乙烯膜，选择不同性质的气体(H₂、He、N₂、O₂、CO₂)研究其透过行为。研究表明：气体以努森扩散和粘性流动的形式透过膜孔，且透过系数与气体分子量的0.5次方成反比，与膜厚度成反比，单孔透过系数与孔半径成3.6次方的关系。根据分离因子和膜结构参数对透过系数的影响，可以进行膜结构的设计，使其成为具备一定防止大分子毒气入侵功能的军用防护服装材料。