Novel Glycolipids Based on Cyclodextrins

Novel amphiphilic cyclodextrins have been prepared by grafting a phospholipid on a modified cyclodextrin through a spacing arm to combine the selectivity in size of cyclodextrins and the transport properties of phospholipids. Synthesis and full characterization by NMR and mass spectrometry have been performed. The aggregation process in water has been characterized by light scattering, DSC and ³¹P NMR. This compound appears to assemble into large objects and displays a very low CMC. The detergent properties of the phospholipidyl-cyclodextrins have been evaluated.     

非理想性对B-Z反应体系时间自组织的影响

从理论和实验上研究了非理想性对B Z反应体系时间自组织行为的影响 ,重点考察了加入惰性电解质对B Z反应体系振荡周期的影响 ,按照Oregonator模型 ,通过小寄生参数法动力学理论分析表明 ,非理想性对B Z反应体系振荡周期的影响体现在振荡周期与铈离子的活度系数成反比 ,而且惰性电解质的加入使得振荡周期进一步加长 .通过一系列实验观测 ,原则上得到了与理论分析一致的结论     

Mimicking Primitive Photobacteria: Sustainable Hydrogen Evolution Based on Peptide–Porphyrin Co‐Assemblies with a Self‐Mineralized Reaction Center

Molecular evolution, with self‐organization of simple molecules towards complex functional systems, provides a new strategy for biomimetic architectonics and perspectives for understanding the complex processes of life. However, there remain many challenges to fabrication of systems comprising different types of units, which interact with one another to perform desired functions. Challenges arise from a lack of stability, dynamic properties, and functionalities that reconcile with a given environment. A co‐assembling fiber system composed of simple peptide and porphyrin is presented. This material is considered a prebiotic assembly of molecules that can be rather stable and flexibly self‐functionalized with the assistance of visible light in a “prebiotic soup”; acidic (pH 2), hot (70 °C), and mineral‐containing (Na⁺, Ti⁴⁺, Pt²⁺, and so forth) water. The co‐assembled peptide–porphyrin fiber, with self‐mineralized reaction centers, may serve as a primitive photobacteria‐like cellular model to achieve light harvesting, energy transfer, and ultimately sustainable hydrogen evolution.     

Electrodeposition of silver-indium alloy from cyanide-hydroxide electrolytes

It is shown that periodical spatio-temporal structures, consisting of phases with different indium content, are observed on the electrode surface during silver-indium alloy deposition from cyanide electrolytes in galvanostatic mode. The effect of electrolysis conditions on the silver-indium alloy appearance and morphology is studied, using optical and scanning electron microscopy; the phase composition of the obtained heterogeneous coatings, overall deposition rate, coating roughness, and microhardness are determined.     

Structure of electroactive coatings based on fullerene and its derivatives

The structures and properties of electroactive coatings based on fullerene and pyridyl-substituted fullerenopyrrolidines were studied using cyclic voltammetry, optical spectroscopy, atomic force microscopy, and other methods. The surface of the electrode of the ITO conducting glass (alloy of indium and tin oxides) was modified by direct casting or the introduction of an electroactive substance into a tetra(n-octyl)ammonium bromide matrix. Changes in the absorption spectra of the coatings agree with the presence of an electronic interaction between adjacent fullerene molecules. Tetra(n-octyl)ammonium bromide is involved in the organization of the fullerene-containing coatings with retention of the layered structure. According to the data of atomic force microscopy, the coating surface depends on both the composition of the solution and preparation method and the nature of addends in a C₆₀ molecule. The dispersion of fullerene in the tetra(n-octyl)ammonium bromide matrix and its interaction with the alkyl groups of the latter provide the hydrophobic microenvironment necessary for reversible electrochemical processes in an aqueous solution to occur. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 308–315, February, 2008.     

Molecular dynamics study of crystalline water ices

The behavior of structures of H₂O crystalline ices Ih, Ic, XI, VII, VIII, VI is studied in molecular dynamics experiment using the potential offered by Poltev and Malenkov. The behavior of the system consisting of one of the two identical interpenetrating, but without any common hydrogen bonds, water frameworks comprising the ice VI structure is also simulated. As a result of simulations, the ice VII structure has collapsed, whereas other systems proved to be stable. The reasons of instability of the ice VII and previously studied ice IV structures in molecular dynamics experiments are discussed. Based on the simulation results of the above-mentioned ices and previous simulation of ices II, III, IX, IV, and XII, the general regularities of dynamic properties of water molecules in crystalline water ices are formulated. Unreliability of results obtained by molecular dynamics in the investigation of self-organizing processes in aqueous systems is shown.     

高分子有机场效应晶体管中退火引起的自组织微观结构变化的研究

为了进一步洞悉高分子薄膜自组织机理和高分子有机场效应晶体管(OFET)载流子迁移率之间的直接关联性,本工作采用先进的同步辐射掠入射X射线衍射(GIXRD)技术,研究了高分子OFET中高分子半导体高度区域规则的聚(3-己基噻吩)(RR-P3HT)工作层薄膜,由不同退火温度所导致的薄膜自组织微观结构的变化.GIXRD测试实验结果显示了,对于不同高分子薄膜制备方法(旋涂法及滴膜法)及不同溶液浓度(RR-P3HT溶液浓度为2.5 mg/ml及3.5 mg/ml)制备的RR-P3HT有机半导体工作层,在氮气气氛下, 关键词： 高分子有机场效应晶体管 同步辐射掠入射X射线衍射 自组织 退火     

甲酸Pt电极电化学氧化体系中时间自组织导致的可利用功耗失

在电极化学反应步骤为控制步骤的条件下,对甲酸阳极氧化体系中出现的电化学振荡的阈值及跨越阈值后状态演化的极限环路径进行了系统动力学计算.同时,根据非平衡电极过程的耗散-涨落理论,进一步对跨越振荡阈值前后的临界区与电化学震荡区的极化曲线及功耗谱进行了随机热力学分析计算.研究结果表明,跨越临界区后单位电化学反应功耗谱出现突降...     

Self-Organization,Entropy Generation Rate,and Boundary Defects: A Control Volume Approach

Self-organization that leads to the discontinuous emergence of optimized new patterns is related to entropy generation and the export of entropy. Compared to the original pattern that the new, self-organized pattern replaces, the new features could involve an abrupt change in the pattern-volume. There is no clear principle of pathway selection for self-organization that is known for triggering a particular new self-organization pattern. The new pattern displays different types of boundary-defects necessary for stabilizing the new order. Boundary-defects can contain high entropy regions of concentrated chemical species. On the other hand, the reorganization (or refinement) of an established pattern is a more kinetically tractable process, where the entropy generation rate varies continuously with the imposed variables that enable and sustain the pattern features. The maximum entropy production rate (MEPR) principle is one possibility that may have predictive capability for self-organization. The scale of shapes that form or evolve during self-organization and reorganization are influenced by the export of specific defects from the control volume of study. The control volume (CV) approach must include the texture patterns to be located inside the CV for the MEPR analysis to be applicable. These hypotheses were examined for patterns that are well-characterized for solidification and wear processes. We tested the governing equations for bifurcations (the onset of new patterns) and for reorganization (the fine tuning of existing patterns) with published experimental data, across the range of solidification morphologies and nonequilibrium phases, for metallic glass and featureless crystalline solids. The self-assembling features of surface-texture patterns for friction and wear conditions were also modeled with the entropy generation (MEPR) principle, including defect production (wear debris). We found that surface texture and entropy generation in the control volume could be predictive for self-organization. The main results of this study provide support to the hypothesis that self-organized patterns are a consequence of the maximum entropy production rate per volume principle. Patterns at any scale optimize a certain outcome and have utility. We discuss some similarities between the self-organization behavior of both inanimate and living systems, with ideas regarding the optimizing features of self-organized pattern features that impact functionality, beauty, and consciousness.     

树状分形结构形成过程的实验研究

对大量金属小球在强电场作用下运动形态的演化全过程用联机摄像装置进行了实时拍摄,通过用Sandbox方法计算其稳定状态的分维数,系统地研究了分维数随电压的变化关系.结果表明：在一定电压范围内金属小球聚集体通过自组织过程形成稳定的树状分形结构,其分维数随外加电压的增加而减小.该结果对研究耗散结构的形成机理和外界动力对耗散结构的形貌影响具有参考价值. 关键词： 分形生长 自组织过程 树状结构 分维数