Synthesis of a Tweezer—like Bis（Phenylthiapropoxy）calix[4]—arene as a Cation／π Enhanced Sensor for Ion—Selective Electrodes

Two novel 25,27-dihydroxy-26,28-bis(3-phenylthiapropxy)-calix[4]arene(3) and 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-5,11,17,23-tetra-tert-butylcalix[4] arene (4) were synthesized for the evaluation of their ion-selectivity in ion-selective electrodes(ISEs).ISEs based on 3 and 4 as neutral ionophores were prepared,and their selectivity coefficients for Ag^ (lg KAg,M^pot)were investigated against other alkali metal,alkaline-earth metal,aluminum,thallium(Ⅰ）,Lead and some transition metal ions using the separate solution method (SSM).These ISEs showed excellent Ag^ seletivity over most of the interfering cations examined,except for Hg^2 and Fe^2 having relative smaller interference(lg KAg,M^pot≤-2.1).     

非离子乳化剂细乳液聚合制备草莓型PSt/SiO2纳米复合微球

通过细乳液聚合,使用非离子乳化体系辛基酚聚氧乙烯醚(CA-897),在纳米二氧化硅水分散介质中,以1-乙烯基咪唑(1-VID)作为辅助单体制备了苯乙烯为核,纳米二氧化硅为壳的草莓型PSt/SiO2有机-无机复合微球.实验范围内得到的复合微球的平均粒径和最终SiO2含量分别介于140～180 nm和19 wt%-31wt...     

Pickering乳滴模板法制备超粒子结构有机/无机杂化微球

Pickering乳滴模板法制备有机/无机杂化的核壳微球越来越引起人们的关注,主要因为该方法制备出的微球具有以无机粒子为壳层的超粒子结构(supracolloidal structure),能够赋予微球独特的功能.胶体粒子在乳滴表面自组装形成有序的球面胶体壳,得到稳定Pickering乳液,固定乳滴表面的胶体粒子来制备核壳结构的微球或者以胶体粒子为壳层的微胶囊(colloidosome).本文综述了我们课题组以Pickering乳滴模板法制备超粒子结构有机/无机杂化微胶囊包括实心微球方面的工作.我们选择具有不同性能、种类的胶体粒子以及具有不同性质和功能的核材料,采用Pickering乳滴模板法,对吸附在乳滴表面的胶体粒子用不同的固定方法制备具有不同结构和性能的微球和微胶囊,利用基于多重Pickering乳液的聚合技术制备双纳米复合的超粒子结构多核聚合物微球.     

In situ generation of biodegradable poly(p-dioxanone) micro-particles by polymerization in supercritical carbon dioxide

Ring-opening suspension polymerization of p-dioxanone（PDO） in supercritical carbon dioxide（scCO₂） was investigated in the presence of poly（caprolactone）-perfluropolyether-poly（caprolactone）（PCL-PFPE-PCL）.The molecular weight,yield and particle morphology of poly（p-dioxanone）（PPDO） were studied.The stabilizer was effective to stabilize the ring-opening polymerization（ROP） of PDO in scCO₂,leading to the formation of resorbable microparticles in a"one pot"procedure.The mean size of PPDO microparticles obtained from suspension polymerizations was sensitive to the rate of agitation and the stabilizer concentration.The method to generate PPDO microparticles has overcome its unprocessable drawback with common organic solvents and provided new product form for biomedical applications.     

Preparation of activated carbons and their adsorption properties for greenhouse gases: CH4 and CO2

Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD, FT-IR and texture property test. The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces. The texture property test reveals that the activated carbons displayed different texture properties, especially the micropore size distribution. The adsorption capacities of the activated carbons were investigated by adsorbing CH4, CO2, N2 and O2 at 25 ?C in the pressure range of 0-200 kPa. The results reveal that all the activated carbons had high CO2 adsorption capacity, one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa. And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa. In the pressure range of 0-200 kPa, the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.     

A note on spectrum distribution of constraint preconditioned generalized saddle point matrices

In this note, results concerning the eigenvalue distribution and form of the eigenvectors of the constraint preconditioned generalized saddle point matrix and its minimal polynomial are given. These results extend previous ones that appeared in the literature. Copyright © 2009 John Wiley & Sons, Ltd.     

Destabilization of artificial biomembrane induced by the penetration of tryptophan

The effect of tryptophan on the membrane stability was studied by using three artificial biological membranes including liposome, Langmuir monolayer and solid supported bilayer lipid membrane (s-BLM) as models. All the results indicate that the penetration of tryptophan can destabilize different artificial biological membranes. The diameter of liposome and the leakage of calcein from liposome increased with the increase of tryptophan concentration because the penetration of tryptophan was beneficial for dehydrating the polar head groups of lipids and the formation of fusion intermediates. π-A isotherms of lecithin on the subphase of tryptophan solution further confirm that tryptophan can penetrate into lipid monolayer and reduce the stability of lipid monolayer. When the concentration of tryptophan increased from 0 to 2 × 10⁻³ mol L⁻¹, the limiting molecular area of lecithin increased from 110.5 to 138.5 Å², but the collapse pressure of the monolayer decreased from 47.6 to 42.3 mN m⁻¹, indicating the destabilization of lipid monolayer caused by the penetration of tryptophan. The resistance spectra of s-BLM demonstrate that the existence of tryptophan leads to the formation of some defects in s-BLM and the destabilization of s-BLM. The values of electron-transfer resistance and double layer capacitance respectively decreased from 5.765 × 10⁶ Ω and 3.573 × 10⁻⁸ F to 1.391 × 10⁶ Ω and 3.340 × 10⁻⁸ F when the concentration of tryptophan increased from 0 to 2 × 10⁻³ mol L⁻¹. Correspondingly, the breakdown voltage of s-BLM decreased from 2.51 to 1.72 V.     

Novel correction method for X-ray beam energy fluctuation of high energy DR system with a linear detector

A high energy digital radiography (DR) testing system has generated diverse scientific and technological interest in the field of industrial non-destructive testing. However, due to the limitations of manufacturing technology for accelerators, an energy fluctuation of the X-ray beam exists and leads to bright and dark streak artifacts in the DR image. Here we report the utilization of a new software-based method to correct the fluctuation artifacts. The correction method is performed using a high pass filtering operation to extract the high frequency information that reflects the X-ray beam energy fluctuation, and then subtracting it from the original image. Our experimental results show that this method is able to rule out the artifacts effectively and is readily implemented on a practical scanning system.     

同轴电喷法制备PCL-蛋清体系复合微胶囊

以鸡蛋的卵清蛋白作为蛋白质药物模板、生物可降解材料聚己内酯(PCL)为药物载体模板,采用同轴电喷法制备PCL-蛋清体系的复合微球.研究了电导率、黏度对于电喷微球成型的影响.核壳溶液推进速率比、电压、溶液质量分数和接收距离等对于所得微球表面形态和结构的影响.利用扫描电子显微镜(SEM)研究了微球的表面形态,用荧光显微镜表征了微球的包覆模式.结果表明:同轴电喷法可以制备PCL-蛋清体系的复合结构微胶囊,其中推进速率比对微球形貌、粒径及其分布的影响比较明显,当PCL与蛋清溶液推进速率比大于10时,将出现具有包覆结构的微球.