Surface morphology evolution of a thin polymeric supramolecular film by tuning interactions

A polymeric supramolecule consisting of symmetric polystyrene-block-poly(4-vinylpytidine) (PS-b-P4VP), dodecylbenzenesulfonic acid (DBSA), and 3-pentadecylphenol (PDP) was formed by proton transfer and hydrogen bonding. The surface morphology,of a thin film of the polymeric supramolecule has been investigated. The spherical PS microdomains embedded in a P4VP(DBSA)(1.0)(PDP)(1.0) matrix are observed for the as-cast film because the weight fraction, f(comb), of the P4VP(DBSA) (1.0)(PDP)(1.0) blocks is much higher than that of PS as a result of the non-covalent interactions of P4VP and DBSA and DBSA and PDR Upon annealing the PS-b-P4VP(1:1)(DBSA)(1.0)(PDP)(1.0) film at high temperatures, the hydrogen bonding between the DBSA and PDP diminishes, which leads to a change of overall morphology from an ordered sphere to a pitted structure.

A solvothermal route to size- and shape-controlled CdSe and CdTe nanocrystals

The size- and shape-controlled CdSe and CdTe nanocrystals, which exhibit obvious quantum confinement effect, have been synthesized by a solvothermal route. It is found that initial precursor concentrations are key factors in controlling the shape of the resulting nanocrystals. Moreover, the obtained nanocrystals are all of zinc blende structure, regardless of their sizes and shapes. A possible mechanism for the formation and growth of the nanocrystals is put forward. It is inferred that the adhesion and subsequent recrystallization of nanocrystals with an assistance of remaining monomers should be a major reason for formation and growth of the elongated nanocrystals.

Luminescence properties of transparent hybrid thin film covalently linked with lanthanide complexes

Novel hybrid thin films covalently doped with Eu3+ (Tb3+) have been prepared via direct routes involving co-condensation of tetraethoxysilane and phen-Si in the presence of Eu3+ (Tb3+) by spin-casting and their luminescence properties have been investigated in detail. Lanthanide ions can be sensitized by anchored phenanthroline in hybrid thin films. Excitation at the ligand absorption wavelength (272 nm) resulted in the strong emission of the lanthanide ions i.e. Eu3+ D-5(0)-F-7(J) (J=0, 1, 2, 3, 4) emission lines and Tb3+ D-5(4)-F-7(J) (J = 6, 5, 4, 3) due to the energy transfer from the ligands to the lanthanide ions.

Confined crystallization behavior of PEO in silica networks

Poly(ethylene oxide) (PEO) and silica (SiO2) organic-inorganic hybrid materials have been synthesized by sol-gel approach. The crystallization behavior of PEO in silica networks has been investigated by differential scanning calorimeter (DSC) and scanning electron micrograph (SEM). The degree of PEO crystallinity in PEO/SiO2 hybrid networks reduces with the increase of SiO2. PEO is in amorphous state when the concentration of PEO is lower than 50 wt% in the hybrid materials. The melting points of PEO in the networks are lower than that of pure PEG, but the melting point of PEO in the networks almost has the same melting point. WAXD and SEM results show that the crystalline behavior of PEO in PEO/SiO2 hybrid system is sternly confined. (C) 1999 Elsevier Science Ltd. All rights reserved.

Crystallization behavior of PCL in hybrid confined environment

Poly(epsilon -caprolactone) (PCL) and silica (SiO2) organic-inorganic hybrid materials have been synthesized by the sol-gel method. The crystallization behavior of PCL in silica networks has been investigated using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The degree of PCL crystallinity in PCL/SiO2 hybrid networks reduces with increase of SiO2. PCL is in an amorphous state when the concentration of PCL is lower than 40wt% in the hybrid system. The melting point of PCL in the networks is lower than, but close to that of pure PCL. WAXD and SEM results show that the crystalline behavior of PCL in PCL/SiO2 hybrid system is strictly confined. (C) 2001 Elsevier Science Ltd. All rights reserved.

Fragmentation reactions of adduct ions [M+CH3CO](+) of isomeric phenylenediamines

The dissociation routes of the adduct ions [M+CH3CO](+) formed by ion-molecule reaction of isomeric phenylenediamines with acetyl ion from acetone under chemical ionization condition were investigated by using collision-induced dissociation (CID) technique performed at ion kinetic energies of 40eV. The adduct ions are intermediate ion-neutral complexes.

Miscibility of poly(ether ether ketone)/poly(ether diphenyl ether ketone) blends

Poly(ether ether ketone) and poly(ether diphenyl ether ketone) homopolymers are prepared by nucleophilic substitution routes. Miscibility of PEEK/PEDEK blends has been studied by wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (d.s.c.). The results indicate that for PEEK/PEDEK blends, when the PEDEK content (weight fraction) is greater than 0.20 and less than 0.75, PEEK and PEDEK components form independent crystalline regions, i.e. they are immiscible; when the PEDEK content is in the range W-PEDEK less than or equal to 0.20 or greater than or equal to 0.75, a rich PEEK- or PEDEK-rich content crystallizes from a mixed melt and PEEK and PEDEK are miscible. Copyright (C) 1996 Elsevier Science Ltd.

Construction of an attenuated Pseudomonas fluorescens strain and evaluation of its potential as a cross-protective vaccine

Ferric uptake regulator (Fur) is a global transcription regulator that is ubiquitous to Gram-negative bacteria and regulates diverse biological processes, including iron uptake, cellular metabolism, stress response, and production of virulence determinants. As a result, for many pathogenic bacteria, Fur plays a crucial role in the course of infection and disease development. In this study, the fur gene was cloned from a pathogenic Pseudomonas fluorescens strain, TSS, isolated from diseased Japanese flounder cultured in a local farm. TSS Fur can partially complement the defective phenotype of an Escherichia coli fur mutant. A TSS fur null mutant, TFM, was constructed. Compared to TSS, TFM exhibits reduced growth ability, aberrant production of outer membrane proteins, decreased resistance against host serum bactericidal activity, impaired ability to disseminate in host blood and tissues, and drastic attenuation in overall bacterial virulence in a Japanese flounder infection model. When used as a live vaccine administered via the injection, immersion, and oral routes, TFM affords high levels of protection upon Japanese flounder against not only P.fluorescens infection but also Aeromonas hydrophila infection. Furthermore, a plasmid, pJAQ, was constructed, which expresses the coding element of the Vibrio harveyi antigen AgaV-DegQ. TFM harboring pJAQ can secret AgaV-DegQ into the extracellular milieu. Vaccination of Japanese flounder with live TFM/pJAQ elicited strong immunoprotection against both V. harveyi and A. hydrophila infections. (C) 2009 Elsevier Ltd. All rights reserved.

Isolation and analysis of the vaccine potential of an attenuated Edwardsiella tarda strain

Edwardsiella tarda is an important aquaculture pathogen that can infect a wide range of marine and freshwater fish worldwide. In this study, a modified E. tarda strain, TX5RM, was selected by multiple passages of the pathogenic E. tarda strain TX5 on growth medium containing the antibiotic rifampicin. Compared to the wild type strain, the rifampicin-resistant mutant TX5RM (i) shows drastically increased median lethal dose and reduced capacity to disseminate in and colonize fish tissues and blood; (ii) exhibits slower growth rates when cultured in rich medium or under conditions of iron depletion; and (iii) differs in the production profile of whole-cell proteins. The immunoprotective potential of TX5RM was examined in a Japanese flounder (Paralichthys olivaceus) model as a vaccine delivered via intraperitoneal injection, oral feeding, bath immersion, and oral feeding plus immersion. All the vaccination trials, except those of injection, were performed with a booster at 3-week after the first vaccination. The results showed that TX5RM administered via all four approaches produced significant protection, with the highest protection levels observed with TX5RM administered via oral feeding plus immersion, which were, in terms of relative percent of survival (RPS), 80.6% and 69.4% at 5- and 8-week post-vaccination, respectively. Comparable levels of specific serum antibody production were induced by TX5RM-vaccinated via different routes. Microbiological analyses showed that TX5RM was recovered from the gut, liver, and spleen of the fish at 1-10 days post-oral vaccination and from the spleen, liver, kidney, and blood of the fish at 1-14 days post-immersion vaccination. Taken together, these results indicate that TX5RM is an attenuated E. tarda strain with good vaccine potential and that a combination of oral and immersion vaccinations may be a good choice for the administration of live attenuated vaccines. (C) 2010 Elsevier Ltd. All rights reserved.

基于合同网协议交互投标的动态调度方法研究

柔性制造系统使生产加工路径有很多可选性,所以调度系统必须考虑机器调度问题。分配规则调度是一种最基本、最具影响力的动态调度方法。然而,分配规则调度方法很少考虑机器顺序选择。兼顾工件选择和机器选择两方面,本文运用交互投标过程,构建基于合同网协议调度的协商规则。研究作业车间动态调度问题,提出并构建了5种合同网规则调度方法。通过实验分析结果表明,基于合同网交互投标模式的规则调度能够大大改善调度系统性能,提高设备的利用率和设备负荷平衡指标。

非线性未建模不确定系统的自适应控制

讨论了非线性未建模不确定系统的自适应镇定问题。通过边界层次分析的方法，提出一和种简单的间接自适应控制方法。该方法克服了现有非线性自适应控制方法容易产生过渡控制的缺点。

考虑负荷的制造单元划分方法

制造单元的划分是实施单元化生产的关键途径。本文提出了一种基于工件制造工艺的并考虑机床负荷的单元划分算法。首先根据工件的加工特征及机床负荷定义了同类实体之间相似性。然后根据启发式规则选择工件族及制造单元的种子元素,并以聚类块内的离散程度作为评价标准,对系统内的工件和机床进行了聚类。

北京石花洞滴水沉积的季节变化及影响因素

Because of the high resolution, stalagmite laminae can play an important role in the paleoclimate reconstructions. However, few investigations for the formation mechanisms of stalagmite lamilae have been done. Based on two-year observation on calcite growth rate at the drip sites, three-year monitoring of hydrodynamics, physics and chemistry of drip waters at different drip sites and the surrounding environments inside and outside the Beijing Shihua Cave, the seasonal variations of calcite growth rate are revealed and the results can be concluded as follows: 1. The drip waters inside the Cave are mostly sourced from the summer rain, and its minimal response-time to the atmospheric precipitation is less than one day. There are three types of response relationships between the precipitation and the drip rate variations: rapid response type, time-lag response type and stable response type. For rapid response type, the drip discharge is recharged through the flow routes along intensive fractures and interconnectivities; for time-lag response type, the drip discharge is recharged by double-porosity system composed of a high conductivity, low storage capability conduit network and a low-conductivity high-storage capability rock matrix under variable boundary conditions; for stable response type, the drip discharge is mainly recharged by seepage flow and base flow. 2. The observation shows that, inside the Cave, the growth rate of calcite is generally lower in rainy seasons and higher in dry seasons. During the rainy seasons, the drip water is characterized by a lower pH value, higher [Ca2+], [Mg2+], [SO42-] and electrical conductivity (EC) values. According to the calculations of saturation index of calcite (SIc), pCO2 of the drip water, as well as the synthetical analysis of other possible factors, the calcite growth rate is found to be principally influenced by the drip water saturation index of calcite (SIc). And the drip rate and pCO2 in the drip water and in the cave air play the secondly important roles in this process. The recharge mode of heavy rainfall events in the rainy seasons should probably be the main driving force that controls the physicochemical properties and calcite sediment of the drip waters. The abrupt decrease of sedimentary rate and the sharp peak of DOC in drip water in the rainy season probably forms the thin opaque (luminescent under ultraviolet radiation) layers observed in the stalagmites, whereas the relatively higher sedimentary rate in the dry seasons may be responsible for the thicker bright layers. The investigation elucidated here preliminarily reveals the formation mechanism of the stalagmite laminae in Beijing Shihua Cave.

龙游石窟洞室群稳定性分析及最佳旅游路线选择

The large ancient underground rock caverns in Longyou is an important component of grotto cultural. Current task facing the long-term preservation of these unmovable cultural relics is arduous and challenging. The deformation failure of the caverns' surrounding rock is deteriorating. The weathering velocity of these caverns is accelerating. With the strength of caverns' surrounding rock worsening, critical rocks were generated in local regions of the caverns' vault and posing a threat to the security of people passing by. Selection of a maximum-security route and construction a aisle in the caverns might be an efficient way to ensure the security of tourists and reach the target of long-term preservation. The deformation and destruction of the ancient underground caverns is primarily dominated by geological conditions and the special structure of caverns. Based on field investigation, several fundamental conditions for deformation and failure are recognized, and nine deformation and fracture patterns of the Longyou grotto are proposed. In order to judge the stability of caverns’ surrounding rock, the element safety coefficient method is presented. An explicit explanation for the meaning of the method is deduced using Mohr-Coulomb strength criterion. Numerical analyses are carried out in the dissertation through FLAC3D code. Through numerical analysis, the stress distribution regularities of the caverns’ roofs, piles and public side wall are analysed, and the stability properties of caverns’ surrounding rock are also assessed. At the same time, the element safety coefficient method is introduced to contrast the stability degree of different regions in caverns. The above analyses are bases for choosing the optimal tourism routes in the caverns of Longyou grotto. The impact of surface load on the stability of shallow buried cavities in Longyou grotto is evaluated, the results show that building load has significant influence on the stability of the No.1 cavern’s roof, pile and public side wall between the No.1 cavern and the No.2 cavern, pedestrian load has less impact on the stability of surrounding rock than building load. The principles for choosing the optimal tourism routes in the caverns are discussed. With these principles, the dissertation makes a systematic research on the geological analytic method, numerical analytic method and meeting tourism requirements method, which are used in selecting the optimal tourism routes in the caverns. In order to achieve the best effect in the process of tourism routes selection, the above three method are integrated through Theory of Engineering Geomechanics Meta-system(EGMS). According to field investigations, numerical analyses, tourism requirements and expert experiences, the optimal tourism routes through No.1 to No.5 cavern are determined preliminarily. The obtained results from the research work are useful for the security aisle's construction, they also have reference value to other projects in practice.

北京周边地区沙尘基的数值模拟与风成物质的REE分析

The sandstorms in 2001 were numerically simulated with NARCM that is a dust emission and transport model developed by Meteorological Service of Canada. In this paper, the dataset of NARCM model is processed and analyzed. The results of processing and analyzing show fair images about influence ranges and transport routes of sandstorms in 2001. The outcomes are compared with aerosol concentrations of atmosphere over Beijing, China and Tango, Japan. It confirms that sandstorm occurs when AK TK K and Si concentration in the air increases. It can be concluded that the NARCM model is appropriate for modeling sandstorm in North of China. The processing and analyzing show that the dust is produced and transported in the Otindag and Bashang. So the Otindag and Bashang are parts of source areas of sandstorms in East Asia. Another focus of this study is the REE of aeolian sediments in Otindag、Bashang、Tianmo Badain Jara、Hulunbeier and Kalahali, South Africa. The analysis on REE shows: There is clear distinction in HREE and LREE's Fractionation Degree (HLFD) between the deserts. HLFD is very high in Hulunbeier, with a value of (La/Lu)N 16.0. The value of (La/Lu)N is 12.7 inTianmo and 8.1 in Octindag. The HREE's Fractionation Degree(HFD) is about 4.0, quite similar in all samples. (3) The LREE's Fractionation Degree(LFD) varies slightly, from 1.5(Badain Jaran) to 2.3(Tianmo).