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为了获得氢氟醚HFE7100、HFE7500的热物理性质参数,补充现有数据不足,为其作为电子元器件的冷却介质、工业清洗剂等工程应用提供技术支持,利用瞬态热线法测量了常压下HFE7100和HFE7500的热导率,并用表面光散射法测量了HFE7100和HFE7500的液相黏度和表面张力。HFE7100和HFE7500的热导率和液相黏度均关联成温度的多项式函数,HFE7100热导率和黏度的实验值和关联式的平均绝对偏差分别为0.37%和1.19%,HFE7500热导率和黏度的实验值和关联式的平均绝对偏差分别0.08%和1.10%。利用改进的van der Waals关联表面张力和温度的关系,HFE7100和HFE7500的表面张力的实验值和关联式的平均绝对偏差分别为0.03 mN·m-1和0.02 mN·m-1。获得的HFE7100和HFE7500的热导率、黏度和表面张力实验数据及方程,可为其工程应用提出数据支持。 相似文献
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碳酸钙和淀粉对聚乙烯薄膜降解性能影响研究 总被引:1,自引:0,他引:1
目的:研究淀粉和CaCO3对塑料薄膜的降解影响。方法:将CaCO3填充膜和淀粉填充膜经自然曝露、紫外线照射和土埋处理,测试拉伸强度、断裂伸长率和分子量的变化。结果:自然曝露30d,CaCO3填充膜和淀粉填充薄膜的平均拉伸强度分别下降80.8%和54.4%,平均断裂伸长率分别下降99.4%和98.3%,分子量分别下降25.3%和13.8%;紫外光照120h,CaCO3填充薄膜和淀粉填充薄膜的平均拉伸强度分别下降14.7%和45.9%,断裂伸长率分别下降97.3%和97.0%,分子量分别下降66.7%和48.3%;土埋203d,CaCO3填充薄膜和淀粉填充薄膜的失重率分别为2.2%和15.0%。结论:CaCO3和淀粉均能加速聚乙烯塑料薄膜的降解,其中CaCO3的光降解性能方面优于淀粉,而淀粉的生物降解性能优于CaCO3。 相似文献
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人造草地和人工渔礁,电池外壳及桥墩,地毯底衬和建筑用包,排水过滤器,河堤,地砖,垫圈,港口和码头,绝缘和工业涂料,牲畜棚地垫和垃圾填埋工程,田径球类运动场地和家具,屋顶材料和路面,鞋底和坚实的车轮,隔音屏障和防振垫。如此多样化的应用和产品之间有什么共同之处?一句话,它们都是用废旧轮胎再生材料为原材料生产出来的。 相似文献
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论述了二甲醚作为二次能源替代民用燃料和车用燃料的可行性和重大意义,阐述了我国能源短缺的危害和开发二次能源的必要性和紧迫性,简述了二甲醚的性质和制备,分析了二甲醚作为二次新能源开发的资源优势和对环境的重大意义及开发前景。 相似文献
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《精细与专用化学品》2006,14(7):38-39
熏燕剂和杀线虫剂:概述;熏蒸剂和杀线虫剂:产品来源、原材料和环境问题;熏蒸剂和杀线虫剂:美国的供应和需求;熏蒸剂和杀线虫剂:西欧的供应和需求;熏蒸剂和杀线虫剂:日本的供应和需求 ;染料:概述;染料:生产方法;…… 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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[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
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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