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为了研究甲烷(CH4)溶解对原油分子间作用的影响机制,利用分子模拟方法,分别构建正庚烷与正庚烷、蜡分子、胶质、沥青质的最低能量构型,分析CH4氛围对原油分子间相互作用的影响。以CH4/原油分子体系模型为研究对象进行分子动力学模拟,考察CH4溶解对原油分子体系黏度的影响,根据原油分子间相互作用、径向分布函数、体积应变、自扩散系数以及体系内聚能密度变化规律揭示CH4溶解对原油分子间作用的影响机制,发现CH4的溶解增大了原油分子间的间距,削弱了体系内原油分子间的范德华作用;体积膨胀为原油分子的热运动提供了更多的空间,原油分子热运动加剧,使得油品的流动能力增强;不同原油分子体系的黏度、径向分布函数、体积应变、自扩散系数以及内聚能密度的变化趋势类似,原油分子体系中蜡、胶质、沥青质的存在并未改变CH4对原油分子间作用的影响机制。 相似文献
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分子识别是超分子化学的一个重要方面.它是分子传递和酶催化的基础.以分子识别为基础,设计和合成了有光谱响应的荧光化学敏感器和离子显色试剂,在生物化学、临床医学、环境科学等与人类生命科学密切相关的领域中有着很强的应用背景.本论文系统总结了环糊精对有机分子的包结特征和包结作用对客体分子光物理性质的影响, 相似文献
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在聚合物驱油藏,聚合物溶液能否顺利注入油层,分子尺寸是关键因素之一,因此,对其进行准确表征是正确选择分子尺寸的前提。本文建立了利用水动力学半径表征聚合物分子尺寸的新方法,可更准确、全面地描述聚合物分子尺寸。利用动态光散射技术,研究了分子量、浓度、矿化度对流体力学半径的影响规律及影响程度,并分析了其原因。 相似文献
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化学科学的研究新领域——超分子化学 总被引:5,自引:0,他引:5
介绍超分子化学的基本概念,阐述超分子体系中分子间弱相互作用、分子识别、分子组装和几种组装体的形态,并指出了超分子化学对科学理论研究的重要意义和广阔的应用前景。 相似文献
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近年来,微波技术在处理水中有机污染物方面的应用越来越受到重视。与常规处理方式相比,微波处理具有反应速度快、高效、节能、选择性强等优势。微波技术可有效降解许多难降解的有机污染物,特别是极性有机污染物。本文研究在微波作用于有机污染物分子的机理,以及微波处理中会对处理产生影响的因素,并总结微波对有机污染物分子会造成什么影响,从分子层面上解释了微波作用的机理,旨在为接下来的研究提供理论指导。 相似文献
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分子印迹技术及其应用 总被引:7,自引:0,他引:7
分子印迹是一项具备特异识别功能的新兴技术。本文介绍了其发展历程、基本原理及应用,并对分子印迹聚合物的制备、表征方法等进行综述。主要介绍了模板分子、功能单体、交联剂、溶剂、致孔剂和反应条件等因素对分子印迹聚合物制备的影响及本体聚合、原位聚合、沉淀聚合、悬浮聚合、表面印迹、电聚合等制备方法。另外对近年来分子印迹技术在生物学、分析化学、天然产物化学、医药以及有机合成等方面的应用进行了总结。 相似文献
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P. Vijayalakshmi R. Subbarao G. Lakshminarayana 《Journal of the American Oil Chemists' Society》1991,68(2):133-137
Cycloaliphatic C21 di- and C22 tricarboxylic acids were prepared by the Diels-Alder reaction of dehydrated castor oil (DCO) fatty acids (containing 48%
conjugated and 42% nonconjugated dienes) with acrylic and fumaric acids, respectively. The reaction temperature, time, catalyst
concentration, and mole ratio of reactants were varied to get maximum yields of the di- and tricarboxylic acids. The unreacted
DCO fatty acids were removed from the products by partition between aqueous methanol and n-hexane. The products were converted
to methyl esters and characterized as the substituted cyclohexene derivatives before and after dehydrogenation with Pd/C in
xylene, hydrogenation with Pd/C in decalin and oxidation with periodate-permanganate reagent and by mass and proton nuclear
magnetic resonance spectrometry. The acids were converted to sodium soaps, mono- and diethanolamides and the corresponding
diol and triol sulfates, and the resulting products were evaluated for their surface-active properties. The sodium soaps showed
better calcium tolerance and poorer foaming power than sodium oleate. The diethanolamides were inferior to lauroyl diethanolamide
in wetting and emulsifying power. The monoethanolamides were better than the respective diethanolamides and lauroyl diethanolamide
in wetting property. The diol and triol sulfates were poorer in wetting and emulsifying ability and better in calcium tolerance
than sodium lauryl sulfate. 相似文献
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民用工业中复合材料桁架的应用和发展 总被引:1,自引:0,他引:1
本文叙述了复合材料桁架的构造、分类和计算方法,突出了复合材料桁架的优越性能和在民用工业中的应用前景;在分析大量文献资料的基础上阐述复合材料桁架杆件的多种加工工艺,并比较不同截面形式对杆件性能的影响;探讨复合材料杆件的破坏机理和分析方法,介绍节点的类型和各自的特点,提出节点及连接部位存在的关键问题;根据国内外复合材料桁架的研究和应用现状,阐述了复合材料桁架的性能和不同的设计方法,总结归纳影响复合材料桁架性能的关键因素和设计中存在的一些问题,并提出改进杆件设计、节点设计和优化复合材料桁架的建议。 相似文献
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Paulina Streimikyte Pranas Viskelis Jonas Viskelis 《International journal of molecular sciences》2022,23(4)
The scientific community and industrial companies have discovered significant enzyme applications to plant material. This rise imparts to changing consumers’ demands while searching for ‘clean label’ food products, boosting the immune system, uprising resistance to bacterial and fungal diseases, and climate change challenges. First, enzymes were used for enhancing production yield with mild and not hazardous applications. However, enzyme specificity, activity, plant origin and characteristics, ratio, and extraction conditions differ depending on the goal. As a result, researchers have gained interest in enzymes’ ability to cleave specific bonds of macroelements and release bioactive compounds by enhancing value and creating novel derivatives in plant extracts. The extract is enriched with reducing sugars, phenolic content, and peptides by disrupting lignocellulose and releasing compounds from the cell wall and cytosolic. Nonetheless, depolymerizing carbohydrates and using specific enzymes form and release various saccharides lengths. The latest studies show that oligosaccharides released and formed by enzymes have a high potential to be slowly digestible starches (SDS) and possibly be labeled as prebiotics. Additionally, they excel in new technological, organoleptic, and physicochemical properties. Released novel derivatives and phenolic compounds have a significant role in human and animal health and gut-microbiota interactions, affecting many metabolic pathways. The latest studies have contributed to enzyme-modified extracts and products used for functional, fermented products development and sustainable processes: in particular, nanocellulose, nanocrystals, nanoparticles green synthesis with drug delivery, wound healing, and antimicrobial properties. Even so, enzymes’ incorporation into processes has limitations and is regulated by national and international levels. 相似文献
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Nicolas A. Deak Lawrence A. Johnson 《Journal of the American Oil Chemists' Society》2007,84(3):259-268
The effects of extraction temperature and preservation method on the functional properties of soy protein isolate (SPI) were
determined. Four extraction temperatures (25, 40, 60, and 80 °C) were used to produce SPI and yields of solids and protein
contents were determined. Three preservation methods were also tested (spray-drying, freeze-drying, and freezing–thawing)
and compared to fresh (undried) samples for each extraction temperature. No differences in yields of solids and protein were
observed among SPIs extracted at 25, 40, and 60 °C; however, SPI extracted at 80 °C yielded significantly less solids and
protein. Extraction temperature significantly affected SPI functionality. As extraction temperature increased, solubility
and emulsification capacity decreased; surface hydrophobicities, emulsification activities and stabilities, and dynamic viscosities
increased; and foaming properties improved. Preservation method also significantly affected SPI functionality. Drying method
did not affect the denaturation enthalpies of SPIs, but spray-dried SPIs had higher solubilities, surface hydrophobicities,
and emulsification stabilities, and lower viscosities, emulsification activities and rates of foaming than freeze-dried SPI
exhibited. Emulsification and foaming capacities and foaming stabilities were similar for both methods of drying. There was
significant interaction between extraction temperature and preservation method for all functional properties except emulsification
capacity. 相似文献
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The current year's growth of Douglas fir contains galactose, unusual in that this carbohydrate makes up 78.7% of the total carbohydrate fraction. An agar diet study was undertaken to determine the effects of galactose, other carbohydrates, and terpenes on western spruce budworm larval mortality, growth rate, and adult biomas production. All concentrations of the carbohydrates and terpenes tested, as well as other mineral elements not tested, were typical of the current year's foliage of Douglas fir. In experiment I, the diet containing 5.61% total carbohydrate did not significantly affect larval mortality when compared to the control diet. However, diets containing 9.45% and 15% total carbohydrate concentrations significantly increased larval mortality 64% and 96.1%, respectively, when compared to the control. Also in experiment I, terpenes alone (78.9% morality) and terpenes in combination with 9.45% and 15% total carbohydrates significantly increased larval mortality (97.2% and 100%, respectively) when compared to mortality on the control diet (44%). To determine which carbohydrate was causing the adverse effect, 6% glucose, 6% fructose, and 6% galactose were placed individually and in combination with terpenes in diets in experiment II. The 6% galactose diet significantly increased larval mortality and reduced growth rate when compared to the control, glucose, and fructose diets. Glucose resulted in 16% less larval mortality, significantly enhanced female larval growth rate and pupal weight, but did not affect male larval growth rate and pupal weight, when compared to the control. Fructose resulted in a significant decrease in larval mortality and a general trend of enhanced female and male larval growth rate and pupal weight. Larval mortality on terpenes alone was not significantly different from the control, but terpenes with 6% galactose increased larval mortality and decreased female and male growth rate and pupal weight significantly when compared to glucose-terpene and fructose-terpene diets. No significant interactions were found between carbohydrates and terpenes in either experiment. 相似文献
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Odilio Alves-Filho 《Drying Technology》2002,20(8):1541-1557
There is an increased demand for convenient foods including ready-to-eat and instant products. These products are desired with minimum concentration of synthetic chemicals. This creates challenges for the food industry and dryers manufactures to develop new technologies to process difficult-sensitive materials and to supply final products with high quality and improved properties. Fruits and vegetables are mainly composed of water, carbohydrates, proteins and lipids. Due to modification of chemical and physical bonds the compounds the material becomes viscous and sticky during processing. Conventional dryers have limitations in handling such sensitive materials. Heat pump dryers have been applied in the production of a diversity of ready-to-eat foods and dried instant products for the last five years at SINTEF-NTNU. Besides being energetically efficient and environmentally friendly, the heat pump drying technology provides a wide range of drying conditions as required to produce powders with improved characteristics. This work describes the new technologies and processing line for the production of instant foods as well as the measurements on the properties and quality attributes for raw, intermediate and final instant products. 相似文献
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Technology and colour are viewed as interfaces between the environment, humans and human activity. Examples are provided of ways of facilitating and improving access to and use of colours by commercial users of colour coatings through improvements in the accuracy of measuring and displaying colour. By analogy, the task of providing effective interfaces within the coatings industry, between the coatings industry and the environment and between the coatings industry and the public and political domain are discussed. Examples of information shortfalls are cited to illustrate how distortions arise. Examples of more effective, integrated technological, organisational and political interfacing are culled from the author's experiences. 相似文献
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[目的]探讨毒死蜱和联苯菊酯在室内外土壤中的消解动态,并预测2种农药作为土壤化学屏障防治白蚁的有效期。[方法]采用气相色谱法测定不同时期土壤中毒死蜱和联苯菊酯的残留量并采用土壤穿透法测定2种农药在土壤中的生物活性。[结果]毒死蜱在室内和室外的半衰期分别为51.3、39.5 d,联苯菊酯在室内和室外的半衰期分别为31.3、44.5 d。毒死蜱和联苯菊酯抗白蚁穿透的最低有效质量分数分别为6.15、5.78 mg/kg,并结合消解动态方程预测出毒死蜱和联苯菊酯作为土壤化学屏障中有效成分的有效期在室内分别为195、29.1 d,在室外则分别为158.4、56.1 d。[结论]得到的白蚁防治有效期结果较好,为白蚁的化学防治提供理论依据。 相似文献