Synthesis and Characterization of Chitosan-Albumin Conjugates as pH-Sensitive Biodegradable Hydrogels

A new kind of biodegradable pH-sensitive drug delivery system was developed via chitosan-albumin conjugate hydrogel. Through changing the feeding modes of reactants, two types of hydrogels(comb-type and reticular-type) were synthesized by amidation reactions between 6-O-succinoylated N-phthaloyl chitosan and albumin. The structures and morphologies of the hydrogels were characterized by SEM. And their water swelling capacity, drug loading and releasing properties at different pH values were also investigate...     

Polyfluorenes containing pyrazine units:Synthesis,photophysics and electroluminescence

A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-...     

功能性有序微结构的制备及潜在应用

随着科技的发展进步,具有特殊功能的有序微结构日渐引起人们浓厚的研究兴趣,并被广泛应用于微电子器件、微反应器、生物化学传感器以及光学器件等领域.本文总结了我们课题组在微观表面图案化和有序微结构制备及应用方面的研究工作,重点介绍我们在该方向工作的最新进展,并对该领域的发展前景进行了展望.     

丙烯酰氯分子的气相光解动力学

利用时间分辨傅立叶变换红外(TR-FTIR)发射光谱研究了气相中CH2=CHCOCl分子的光解动力学.观测到振动激发的光解碎片分子CO(ν≤5),HCl(ν≤6),C2H2和相应的两个光解离通道:C-Cl键断裂和HCl消除通道.通过分析转动分辨的红外发射光谱得到CO和HCl的初始振转能量态分布,由此提出CH2=CHCOCl的气相光解机理并阐明了内转换等非绝热过程在影响反应途径中的关键作用.     

MOLECULAR STRUCTURE OF DINUCLEAR COBALT COMPLEX WITH CHELATING 1, 3-BIS (DIPHENYLPHOSPHINO ) PROPANE LIGAND

<正> Co2 ( CO ) 6 (dppp ) Cdppp = 1,3-bis ( diphenylphosphino ) propane = Ph2P(CH2)3PPh2D, Mr=698. 38, monoclinic, space group P21/c, a=14. 952(8) , b = 13.44(2), c = 16. 72(1) A. β=110.56(4)°, V=3147(9) A3, Z = 4, A=1. 47 g/cm3, λ(MoXα) = 0. 71069 A, F(000) = 1424, λ(MoKα) = 11. 93 cm-1, R = 0. 032 and Rw = 0. 044 for 4553 observed independent reflections with I>4. 0σ(I). The molecular structure of the complex shows that the dppp ligand chelates one of the two cobalt atoms of the complex molecule, and there are two bridging carbonyl groups between the two cobalt atoms. The Co-Co bond length is 2. 534(3) A . The chelating dppp ligand results in the asymmetrization of the molecule.     

1，2—二氯丙烷裂解反应光窗结焦机理的研究

有机化合物在光窗上的结焦严重地影响激光引发化学反应及光学原位实时探测。本文报道在1，2－二氯丙烷反应系统中，光窗结焦现象同时存在于激光引发反应及热反应过程中，对光窗在300℃条件 下的结焦机理研究表明，少量氧气在光窗结焦过程中起关键作用。结焦前驱体的红外光谱研究表明，前驱体的可能结构为1－丙炔－1，3－二醇的缩聚体。该化合物极易通过缩聚反应形成更大的分子，最终导致光 窗结焦。对系统及反应物进行彻底除氧，光窗结焦现象大为改善。     

电感耦合等离子体发射光谱法测定钇铝石榴石中掺杂Yb(Ⅲ)离子

采用碳酸钠-硼砂(质量比1：1)做熔剂分解钇铝石榴石,并确定了熔剂的最优化条件．以电感耦合等离子体光谱法对样品中掺杂Yb(Ⅲ)离子作了定量检测考察了样品和熔剂中单个基体和混合基体对分析结果的影响．发现单个基体Y对Yb的测定有增强效应．基体A1对Yb的测定有一定的抑制作用;基体对Yb测定的干扰可通过基体匹配进行消除元素的俭出限为2μg／L,标准加入回收率为88％～100％实际样品7次检测的RSD为2．1％。本方法可以较好地满足实际样品分析的需要。     

反相流动注射-化学发光法测定苯胺

在酸性介质中,苯胺与过量亚硝酸盐重氮化,剩余亚硝酸盐快速氧化亚铁氰化钾,生成的铁氰化钾与鲁米诺发生化学发光反应。据此,建立了反相流动注射 化学发光法测定苯胺的新方法。方法的线性范围为0 070～10.0mg L,检出限为0 03mg L,相对标准偏差(n=11,ρ=1.0mg L)为2 0%。方法已用于环境水样中苯胺的测定。     

Study on thermal stability of poled non-linear optical polymers

A logarithmic expression is proposed to describe relaxation of the polar order in side chain polymers,together with a new way of plotting temperature dependent relaxation data.This results in a straight line extending even below the glass transition temperature in the case of poled nonlinear optics (NLO) side chain polymers.A simple procedure to determine the rotational diffusion constant Dr is given and Dr values of several polymer systems have been evaluated and compared with each other.It appears that,starting from the conventional and well known poled polymer system currently applied,a further lowering of Dr by about 3 orders of magnitude is necessary in order to reach an acceptable orientational stability or lifetime of poled polymers for practical applications.Attempts have been made to introduce electron push-pull substituents into high thermostable molecular frameworks and results of preliminary measurements are reported.     

Higher alcohol synthesis over Cu-Fe composite oxides with high selectivity to C2+OH

Cu-Fe composite oxides were prepared by co-precipitation method and tested for higher alcohol synthesis from syngas. The selectivity to C2+OH and C6+OH in alcohol distribution was very high while the methane product fraction in hydrocarbon distribution was rather low, demonstrating a promising potential in higher alcohols synthesis from syngas. The distribution of alcohols and hydrocarbons approximately obeyed Anderson-Schulz-Flory distribution with similar chain growth probability, indicating alcohols and hydrocarbons derived from the same intermediates. The effects of Cu/Fe molar ratio, reaction temperature and gas hourly space velocity (GHSV) on catalytic performance were studied in detail. The sample with a Cu/Fe molar ratio of 10/1 exhibited the best catalytic performance. Higher reaction temperature accelerated water-gas-shift reaction and led to lower total alcohols selectivity. GHSV showed great effect on catalytic performance and higher GHSV increased the total alcohol selectivity, indicating there existed visible dehydration reaction of alcohol into hydrocarbon.