壳聚糖缓释体系研究进展

综述了壳聚糖在缓释系统方面的最新研究进展。包括壳聚糖衍生物缓释体系的研究、壳聚糖缓释体系在医药系统的应用和吸附-控释复合体系的研究,重点介绍了壳聚糖衍生物缓释体系的研究,壳聚糖衍生物缓释体系分为壳聚糖衍生物缓释微球、壳聚糖纳米粒、壳聚糖缓释片、壳聚糖缓释微囊、壳聚糖缓释膜和壳聚糖水凝胶缓释体的研究等六个部分。壳聚糖缓释体系作为一项新技术在医药体系具有广泛的应用前景。     

壳聚糖季铵盐研究进展

壳聚糖是应用广泛的天然多糖,资源丰富,壳聚糖化学改性后得到的衍生物改善了壳聚糖的功能,并保留了壳聚糖本身的可生物降解性、生物相容性等优点.其中壳聚糖的季铵盐改性明显提高了其抑菌、抗氧化等活性,并增强了壳聚糖的水溶性,近年来研究较多,介绍了壳聚糖季铵盐的化学改性及应用研究进展,这些化学改性方式均在一定程度上提高了壳聚糖的...     

壳聚糖衍生物在化妆品中的应用

综述了壳聚糖衍生物:羟基化壳聚糖、羧基化壳聚糖、酰化壳聚糖、壳聚糖季铵盐的制备方法,并介绍了它们在化妆品方面的应用性能.     

强化壳聚糖絮凝性能研究进展

从壳聚糖的絮凝机理入手,详细阐述了增加壳聚糖的溶解性、改变壳聚糖在溶液中的分子构象、确定适宜操作条件等提高壳聚糖絮凝性能的方法,并介绍了壳聚糖在各个领域的强化研究成果。最后对壳聚糖的未来发展趋势进行了展望。     

壳聚糖与羧甲基壳聚糖对铁离子的络合性能研究

考察了壳聚糖及羧甲基壳聚糖对Fe(Ⅱ)及Fe(Ⅲ)的络合性能,优化了壳聚糖及羧甲基壳聚糖与铁离子的络合条件,包括pH值、壳聚糖或羧甲基壳聚糖用量、铁离子的起始浓度、络合时间等.结果表明,壳聚糖及羧甲基壳聚糖载铁量多且能形成稳定性适度的络合物,有开发补铁剂的应用前景.     

壳聚糖及丁二酸酐酰化壳聚糖双氧水降解行为的研究

在简单均相体系下．研究了壳聚糖及丁二酸酐酰化壳聚糖在双氧水中的降解特性。采用鸟氏粘度计，利用一点法测量了降解过程中壳聚糖及丁二酸酐酰化壳聚糖的分子量，讨论了该体系下壳聚糖及丁二酸酐酰化壳聚糖的降解速率．通过红外光谱分析了双氧水对低分子量壳聚糖和低分子量丁二酸酐酰化壳聚糖结构的影响。结果表明．在该体系下·壳聚糖及丁二酸酐酰化壳聚糖的降解主要发生在反应开始后的2～3h内．此后降解产物的分子量逐渐趋于20000；相同条件下，丁二酸酐酰化壳聚糖的降解程度高于壳聚糖；红外光谱表明．采用该降解体系制备的降解产物主链结构基本没有发生变化。     

含硫改性壳聚糖气凝胶的合成及对Cu2+吸附的研究

以壳聚糖和二硫代二丙酸二甲酯为原料,通过乙酰化改性,成功制备了壳聚糖衍生物。然后以壳聚糖/壳聚糖衍生物为原料,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,合成了壳聚糖气凝胶/壳聚糖衍生物气凝胶。通过红外光谱（FT-IR）、X射线衍射（XRD）和热重分析（TG）研究了壳聚糖/壳聚糖衍生物的结构性能;同时采用扫描电镜（SEM）对壳聚糖气凝胶/壳聚糖衍生物气凝胶的形貌进行了表征;并且探究了壳聚糖气凝胶/壳聚糖衍生物气凝胶对Cu²⁺的静态吸附实验。FT-IR结果表明壳聚糖衍生物被成功地合成;XRD和TG分析表明相较于壳聚糖,壳聚糖衍生物的结晶度和热稳定性均降低;SEM显示衍生物气凝胶的孔的数量增多。吸附实验结果表明壳聚糖衍生物气凝胶的吸附性能有了较大提高;在25℃,吸附剂添加量50.0mg且Cu²⁺溶液初始质量浓度100mg/L,pH值5时,壳聚糖衍生物气凝胶在60min时达到吸附平衡,最大吸附量为48.26mg/g,比未改性的壳聚糖气凝胶的吸附量提高了63.37%。     

超声波技术制备微晶壳聚糖

利用天然高分子壳聚糖为原料制备了微晶壳聚糖,以特性粘度为主要性能指标,研究了壳聚糖浓度、降解时间、NaOH的浓度等对壳聚糖特性粘度的影响,经单因素试验得出了最优工艺条件为:壳聚糖浓度为1.2%,降解时间为4 h、NaOH的浓度为5%;同时,研究了微晶壳聚糖的保水值(WRV),与壳聚糖相比,微晶壳聚糖的保水值提高近一倍。     

壳聚糖复合物在水果保鲜中的应用研究进展

壳聚糖用作食品的保鲜剂具有良好的成膜性和强的抗菌保鲜防腐能力,再加上其来源广泛、天然、无毒副作用及涂膜保鲜简单易行等诸多优点,因而受到了国内外的广泛研究。本文综述了以壳聚糖为主要原料的壳聚糖复合物,如壳聚糖-有机酸复合物、壳聚糖-维生素C复合物、碘化复合物、壳聚糖-纳米材料复合物、壳聚糖-CaCl₂-乳清蛋白-柠檬酸复合物、钙复合巯基化壳聚糖复合物、壳聚糖稀土复合物在水果防腐保鲜方面的应用,并对壳聚糖复合物的保鲜前景进行了展望。     

甲壳素衍生物的制备工艺

介绍了多种甲壳素衍生物的制备工艺和生产方法 ,包括壳聚糖、羧甲基甲壳素、羧甲基壳聚糖、乙酰化壳聚糖、羧丙 (乙 )基壳聚糖、微晶甲壳素及壳聚糖、盐酸氨基葡萄糖、甲壳素硫酸盐、溴化甲壳素、N-乙基壳聚糖、季铵化壳聚糖、壳聚糖接枝共聚产物等十多种。     

海水淡化的现状发展以及几种典型蒸发器的研究

介绍海水淡化的优势、技术现状以及发展趋势,对海水淡化的方法进行了总结,分析蒸发技术现状及发展趋势。介绍蒸发装置选型的一般原则以及几种典型蒸发设备的优缺点。     

Color in the hands of the artist and eyes of the beholder

The perceptual effects that inform a series of paintings are analyzed and described using the tools of the visual psychologist and psychophysiologist.     

Analysis of the steady-state kinetics of consecutive and of parallel electrode reactions

A little known method of analysis of processes with consecutive or parallel rate-determining steps is described with applications and extensions, which have proved valuable in mechanistic studies.Extension to equilibrium and mixed-potential systems is described.     

Application of rayleigh spectroscopy to the study of emulsion and dispersion polymerization and polymers

Application of Rayleigh spectroscopy for characterization of particle size in nonaqueous dispersion and water-based emulsion paint resins is described. The technique allows a straightforward and rapid estimation of particle size; the measurement does not require exact determination of scatterer concentration. For monodisperse samples, unambiguous results are obtained for particles at least up to 50 μm in diameter; for polydisperse samples, an average size heavily weighted by large particles is obtained. Typical experimental results on monodisperse and polydisperse water-based latexes and on polydisperse nonaqueous dispersion resins are described. In the latter case, comparison of electron micrograph and light scattering size determinations indicates that the light scattering experiment yields approximately a z-average radius. Observations on particle formation and growth during polymerization are also described.     

Investigation of the decomposition processes in double-base propellants and nitrocellulose under vacuum and oxygen

There is described the application of an automated vacuum stability test in following the decomposition and stability of double-base propellants and nitrocellulose. There is also described a manometric stability test of propellants based on the decomposition in oxygen. This method makes possible to determine small differences of chemical stability and to substitute the time consuming methods based on HPLC.     

国内外涂料当前的发展特点及趋势

介绍国内外涂料工业的发展特点以及国内外建筑涂料、工业涂料和特种涂料的发展方向。     

辣椒碱的研究进展及应用

介绍并比较近年来国内外辣椒碱的制取、纯化技术及作为药物在临床上的应用,并对其应用前景作了简要评述,对今后的研究工作作了展望。     

分离式双管板列管换热器的设计与制造

论述了双管板换热器材料选择、管板胀管槽等结构的设计、双管板检漏设计、最佳胀管压力计算等 ,以及双管板制造中内侧管子管板液压强度胀接、外侧管子管板强度焊接、双管板间空腔内和管子管板焊接接头气密性试验的要求     

A kinetic study of the adsorption and desorption process of two commercial molecular sieves

A mathematical model and its numerical solution is presented to describe adiabatic adsorption—desorption processes in a fixed bed when the mass and heat transfer can be described by external film transfer coefficients only, which is especially interesting in the case of non-uniform, irregular particles. A new method to measure such rates is presented, based on continuous weighing of a through-circulated bed. The measured rates can be checked against the difference in humidity and temperature between the outlet and inlet air in order to minimize errors.The comparison between experimental results and calculations showed that the adsorption process in a bed of molecular sieve pellets can not be described with a constant mass transfer coefficient; the desorption process is better described although not entirely satisfactorily. In the case of a honeycomb molecular sieve, a constant mass transfer coefficient described both the adsorption and desorption processes satisfactorily.     

Aminochlorobenzenesulphonic acids: Synthesis of the missing isomers and corrections to the literature

Unambiguous routes to five aminochlorobenzenesulphonic acids are described. Two of these isomers have not been described before and this work shows that the literature on the other three is confused. The ¹³C-n.m.r. spectra of all ten isomers have been measured. The isomers have been used to identify the products from the sulphonation of 2-, 3- and 4-chloroaniline in which HPLC analysis has been invaluable.