Mn(Ⅱ)对壳聚糖降解制备低聚壳聚糖的影响

将壳聚糖进行液态均相配合反应制得壳聚糖锰配合物，IR、元素分析及热分析等检测证实了壳聚糖锰配合物中配位键的存在，且显示壳聚糖锰配合物存在有利于壳聚糖高分子链断裂的弱势结构。以H2O2对壳聚糖．Mn(Ⅱ)配合物及壳聚糖进行氧化降解，考察降解过程中粘度的变化及降解产物分子量分布，在相同的降解条件下，壳聚糖锰配合物的降解速度明显高于壳聚糖，且降解产物分子量分布较壳聚糖直接降解窄。对壳聚糖锰配合物降解反应动力学研究表明壳聚糖锰配合物对H2O2分解不存在催化作用，其降解反应与壳聚糖的差异只与其结构有关。对降解产物进行脱金属处理，所得低聚壳聚糖含锰量为0。     

壳聚糖衍生物的合成及其在化妆品中的应用

综述了目前几类壳聚糖衍生物：羧甲基壳聚糖、羧基壳聚糖、壳聚糖羟烷基衍生物、壳聚糖或酰基化衍生物、壳聚糖磺化衍生物、壳聚糖季铵盐的制备方法．分别介绍了它们的性能和在护肤品、洗发香波、头发调理剂、定型剂以及洗浴剂中的应用，同时举出了较典型的应用实例，为此方面研究工作提供了参考配方。     

壳聚糖及其衍生物的制备和保湿吸湿性能评价

简要介绍了壳聚糖及其衍生物的制备方法和物化性质。以甘油、山梨醇和透明质酸为参照物，在一定相对湿度下考察了壳聚糖、羧甲基壳聚糖、N—羧丁基壳聚糖等几种保湿剂的保湿吸湿性能。结果显示，羧甲基壳聚糖和N—羧丁基壳聚糖的保湿吸湿性能最优，完全可以替代透明质酸，作为多种化妆品的保湿剂。     

壳聚糖及其衍生物在重金属污染治理中的应用

壳聚糖是一种生物相容性和可生物降解的天然高分子有机聚合物，可以被改性和转化为各种壳聚糖衍生物。介绍了壳聚糖的制备方法、表征方法及其改性方法，阐述了壳聚糖及其衍生物在去除废水中重金属的应用研究进展。壳聚糖经过改性后显著提高了其表面的活性基团及其对金属离子的吸附效果。综述壳聚糖的相关信息以探索壳聚糖作为吸附剂去除废水中金属离子的潜力。     

利用纤维素酶催化水解壳聚糖的研究

利用纤维素酶催化降解壳聚糖，分别研究了pH值、温度、酶／糖及反应时间等因素对壳聚糖相对分子质量的影响，得到的最佳反应条件为：pH为5．6、n（酶）／n（糖）为0．1／1．0、反应温度为50℃、反应时间为6h。用纤维素酶催化降解壳聚糖只能得到最低平均相对分子质量为18000的低聚壳聚糖。为了得到更低相对分子质量的壳聚糖，在壳聚糖酶降解后加入一定量双氧水继续降解。研究了双氯水加入量及加入时间的影响，最终可得到平均相对分子质量为1500的低聚壳聚糖。     

壳聚糖及低聚壳聚糖在日用化妆品中的应用

随着壳聚糖及其衍生物、低聚壳聚糖研究的迅速发展，其研究内容和应用范围越来越广泛，从壳聚糖及低聚壳聚糖在护发、护肤、美容等方面对其在日用化妆品中的应用进行了综述，并对其发展前景进行了简要评述。     

含硫壳聚糖研究——氨基硫脲接枝壳聚糖的合成

壳聚糖与苯甲醛反应制得保护氨基的Schiff碱壳聚糖，再与氨基硫脲反应合成了一种含硫的新型接枝壳聚糖，主要中间体及最终产物经红外光谱验证，与设想结构一致。     

氮杂冠醚壳聚糖研究(Ⅲ)——双羟基中环二胺交联壳聚糖的制备

以壳聚糖为原料，与经环氧活化的双羟基中环二胺反应，制备了一种新型的氮杂冠醚交联壳聚糖。主要中间体及产物经红外光谱、X-射线粉末衍射等进行了确证。     

壳聚糖絮凝有机废水机理的研究

研究了壳聚糖絮凝处理高浓度含铜离子有机废水，合适pH值为5．5－6．5，壳聚糖的最佳用量与废水的化学需氧量及浊度有关，絮凝效果与搅拌时间无关，壳聚糖明显优于无机絮凝剂Al2（SO4），同时能螯合去除大量有毒重金属铜离子。壳聚糖絮凝有机废水的机理是壳聚糖所带正电与溶液悬浮质所带负电之间的静电引力。     

壳聚糖衍生物—新型的高效水处理剂

羧甲基壳聚糖克服了壳聚糖只能在酸性条件下使用的缺陷,其应用范围大大拓宽,在废水处理时,可使Cu2+、Ce4+、Pb2+、Sn2+、Cd2+等金属离子形成沉淀析出,并且对染料废水的COD去除率也能达到92%以上;壳聚糖季铵盐的絮凝能力比壳聚糖有了很大提高,可应用于味精生产的废水处理和炼油废水的处理与灭菌,当取代度为92.68%时絮凝效果最佳;另一种壳聚糖衍生物--壳聚糖冠醚对Pb2+、Cu2+、Hg2+有很强的络合吸附能力,仲胺型壳聚糖冠醚在Pb2+-Hg2+二元混合体系中还有选择吸附作用;香兰醛改性的壳聚糖颗粒装填于吸附柱可去除工业废水中99.9%以上的Pb2+和Cd2+.壳聚糖衍生物均具有良好的生物降解性,应用于工业废水处理具有广阔的发展前景.     

A Review of Contemporary Views of Theories of Adhesion

The once distinct and independent theories of adhesion have been losing their isolation and converging. Ideas of the effects of surface roughness, once dismissed as irrelevant except in the case of textiles, have been revised; albeit on a smaller scale as details of surfaces have been revealed by sophisticated techniques. Electrostatic interactions across an interface have been more deeply explored and their significance recognised and expounded. Diffusion of groupings and chain segments within a polymer have been related to the possibilities of interaction with a variety of surfaces. Perhaps most important, theories of adsorption have been extended in depth. The precise nature of the molecular interactions have been recognised and quantified. In doing this the contribution of diffusion and elastoplastic phenomena have been integrated. These developments are collated and analysed to present the present understanding of the concepts.     

A Review of Contemporary Views of Theories of Adhesion

The once distinct and independent theories of adhesion have been losing their isolation and converging. Ideas of the effects of surface roughness, once dismissed as irrelevant except in the case of textiles, have been revised; albeit on a smaller scale as details of surfaces have been revealed by sophisticated techniques. Electrostatic interactions across an interface have been more deeply explored and their significance recognised and expounded. Diffusion of groupings and chain segments within a polymer have been related to the possibilities of interaction with a variety of surfaces. Perhaps most important, theories of adsorption have been extended in depth. The precise nature of the molecular interactions have been recognised and quantified. In doing this the contribution of diffusion and elastoplastic phenomena have been integrated. These developments are collated and analysed to present the present understanding of the concepts.     

Structural,mechanical, and gas barrier properties of poly(ethylene terephthalate) nanohybrid using nanotalc

Amorphous poly(ethylene terephthalate) (PET)/nanotalc nanohybrids have been prepared through solution casting route. The fine dispersion of nanotalc clay in the polymer matrix has been examined through transmission electron microscopy (TEM). The intercalation and interaction of nanoclay have further been confirmed using X-ray diffraction, ultraviolet, and Fourier transform infrared techniques. The thermal stability has been tested via thermogravimetric analysis and nanohybrids have been found thermally stable. The glass-transition temperature has been further confirmed through DTA and differential scanning calorimetry analysis which has been increased in the presence of nanotalc arising from greater interaction. The nanohybrids have been tested for their mechanical performances and have been found to have improved mechanical responses for nanotalc-filled nanohybrids. The modulus has been increased whereas toughness has been compromised meagerly. The modulus values have been theoretically predicted using various micromechanical models. The microhardness of the nanohybrids has been examined through Vicker hardness test. The theoretical prediction of the hardness values has been done using different micromechanical models. The structural development upon uniaxial stretching of the samples has been studied using small-angle X-ray scattering and wide-angle ray diffraction. The stretched samples have found to have short-range ordering as well as increased blob size and better coherency in the presence of nanotalc. The aspect ratio has been increased upon stretching. The inclusion of nanotalc has induced high barrier for gas permeation as compared to pure PET. The oxygen transmission rate has been found to decrease up to 64% for 8 wt % of filler concentration. The prediction of the permeability data has been done using different models considering different aspect ratios. The permeability values have been predicted very closely and nanohybrids have been found suitable for practical applications such as packaging. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48607.     

关于陶瓷墙地砖的深加工及其机械

本文简要回顾了陶瓷墙地砖深加工的工艺理论和机械设备。对陶瓷墙地砖深加工的自动抛光生产线和组成生产线的工艺单机作了一般介绍。指出设计陶瓷墙地砖深加工工艺单机时要注意的主要问题,并提供了解决这些问题的方法。     

INVITED REVIEW ABSORPTION OF NOX GASES

Oxidation of nitric oxide is an important step in NO_x absorption. Recent advances namely catalytic oxidation and the use of slrong oxidizing agents have been reviewed. The refinements which have been made in the kinetics of NO oxidation have been discussed. Several liquid phase absorbents have been suggested for the NO removal, particularly for the purpose of pollution abatement. Different models for NO oxidation using nitric acid have been analysed and the limitations of published information have been brought out.

Absorption of tetravalent nitrogen oxide (NO₂ and N₂O₄) has received considerable attention. The absorbents include water, nitric and sulfuric acids, sodium hydroxide, sodium sulfite and sodium chlorite. Absorption in water and nitric acid is important in the manufacture of nitric acid. The published information on the mechanism of NO₂ and N₂O₄ absorption in water has been critically analysed. The problem of nitrous acid decomposition has been analysed on the basis of film theory. The predictions agree favourably with the available experimental data.

A new mathematical model has been developed for a packed column. Performance charts have been prepared which take into account the effects of concentration of nitric acid, superficial liquid velocity, temperature and the partial pressures of various components. A simplified model on the basis of NO oxidation has also been presented.

Various process design aspects have been discussed in detail. Optimum values for various operating parameters exist and basis for their selection has been explained. Some engineering aspects such as the selection of equipment and material of construction have also been discussed. A comparison between semi-batch and continuous modes of operation has been presented. The problem of the manufacture of pure nitrites has been analysed

Specific recommendations have been made regarding the use of equations and procedures in design. The knowledge gaps have been clearly brought out and suggestions have been made for future work     

水处理除盐系统出力不足的原因分析及处理措施

针对郑州热电厂五期补给水处理一级除盐系统酸碱耗大、自用水率高、出力严重不足等问题，对现场进行了调查研究，分析了主要原因，并提出了相应的处理措施，最终使问题得以解决。     

The Application of Biocatalysis in the Preparation and Resolution of Morita-Baylis-Hillman Adducts and Their Derivatives

The Morita-Baylis-Hillman (MBH) reaction affords highly functionalised allylic alcohols containing a new stereogenic centre. These MBH adducts are very versatile and have been transformed into a large range of products, some of which have medicinal potential. Several examples of asymmetric syntheses of MBH adducts have been reported, although a generally applicable method remains to be developed. Biocatalytic approaches for the synthesis and enzymatic kinetic resolution of MBH adducts have been reported, and are discussed in detail in this review. Enzymes able to catalyse the asymmetric MBH reaction have been identified, but selectivity and efficiency have generally been low. Lipases, esterases and nitrile-converting enzymes have all been successfully applied in the resolution of MBH adducts, with excellent selectivity being realised in most cases.     

SIGNIFICANCE OF THE CENTRAL PLUME VELOCITY FOR THE CORRELATION OF LIQUID PHASE MIXING IN BUBBLE COLUMNS

The knowledge of the flow patterns of each phase of bubble column reactors is of considerable importance for the rational design and scale-up. The hydrodynamic models for the liquid phase have been reviewed. The models have been based on some form of pressure balance or energy balance. These two approaches have been compared and recommendations have been made regarding the range of applicability of the individual models. A comparison between the predicted and the experimental liquid velocities has been presented whenever possible. The range of variables has been pointed out for which further investigations are needed. The empirical and theoretical models for the mixing behavior of the different phases of bubble column reactors have also been reviewed.     

Vapor-liquid equilibria in the system of glycidol synthesis products

Vapor-Liquid equilibrium (VLE) data have been calculated for systems made up by glycidol synthesis products and have been compared with data available from the literature. The VLE data reported for the systems have been optimized using the NRTL and UNIQUAC models, and the model parameters and their accuracy have been estimated. The VLE in binary and multicomponent systems has been simulated.     

酞菁类光敏染料的研究进展

酞菁类光敏染料具有低成本、化学性质稳定、对环境友好等优势,越来越受到人们的重视,近年来已成为研究的热点。研究人员现已对许多种酞菁类光敏染料进行了大量研究,数千种不同分子结构的该类型化合物已被合成,研究表明在取代基的作用下,与不同的金属络合所表现出的性能、特征各不相同,从而得出了一些能有效改善酞菁光谱吸收特性和提高光电转...