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1.
针对目前国内外研究植物有效成分的常用提取、分离技术和方法,对比分析了各种常用的提取、分离技术和方法的适用性和局限性,通过多种提取方法的例举描述了现代植物有效成分的研究现状,并阐述了植物提取分离技术的发展前景。  相似文献   

2.
The role of enzymes in modern detergency   总被引:1,自引:0,他引:1  
Enzymes have effectively assisted the development and improvement of modern household and industrial detergents. The major classes of detergent enzymes—proteases, lipases, amylases, and cellulases—each provide specific benefits for application in laundry and automatic dishwashing. Historically, proteases were first to be used extensively in laundry detergents. In addition to raising the level of cleaning, they have also provided environmental benefits by reducing energy consumption through shorter washing times, lower washing temperatures, and reduced water consumption. Today proteases are joined by lipases and amylases in improving detergent efficacy especially for household laundering at lower temperatures and, in industrial cleaning operations, at lower pH levels. Cellulases contribute to overall fabric care by rejuvenating or maintaining the new appearance of washed garments. Enzymes are produced by fermentation technologies that utilize renewable resources.  相似文献   

3.
张婉萍  林梅  王恒  岳恒  郑时莲 《精细化工》2023,40(7):1428-1437
中草药是中国传统的纯天然药物,具有来源极广、药物残留少、毒副作用微小和无抗药性等优点。中药材中的一些活性成分具有抗炎、抗氧化、抗菌等功效,被广泛应用于日常保健和临床医疗中。近几年来,越来越多的高安全性、温和、低刺激性的中草药活性成分作为天然添加剂应用在化妆品中。同时,含中草药的化妆品在全球市场上的需求量正在不断增加,这为中草药及其活性成分在化妆品中的应用研究提供了思路和动力。首先,总结了中草药中6种常见活性成分,如酚类化合物、类黄酮、皂苷、萜类化合物、类胡萝卜素和天然多糖的结构和功能;接着,综述了中草药活性成分的5大功效:保湿、祛斑美白、防晒、抗皱与祛痘及作用机制;最后,提出了中草药功效性成分在化妆品应用中存在的问题,并指出了未来发展方向。  相似文献   

4.
5.
It has been shown that a wide range of organic compounds in aqueous solutions is photocatalytically oxidized to carbon dioxide in the presence of titanium dioxide with near-UV radiation. The photocatalytic mineralization of thiocarbamate derivative pesticides (EPTC, butylate, molinate, vernolate and cycloate) in water by illuminated TiO2 has been studied. The determination of the effects of various kinetic factors on the photocatalytic degradation and the determination of the nature of the principal intermediates form part of the focus of this study. The degradation rate of these thiocarbamates in a continuous recirculation mode approximates first-order kinetics. It was demonstrated that photocatalyzed degradation of thiocarbamate active ingredients does not occur instantaneously to form carbon dioxide, but through the formation of long-lived intermediate species. Photocatalytic intermediates detected during the degradation of thiocarbamates were identified by GC/MS techniques. Intermediates detected in the photocatalytic oxidation of thiocarbamates in water solutions are in excellent agreement with products identified from the atmospherically important reactions of OH radical with thiocarbamates. Particular attention will be paid to the carbon dioxide formed from the illuminated suspension in order to demonstrate not only apparent destruction but also complete mineralization. The degradation of a two-component mixture was carried out and compared to results obtained with single-component studies.  相似文献   

6.
<正>我国磷化工产业规模大,国内销售已处于供大于求的饱和状态,随着新的磷化工企业不断诞生和国家政策向保护磷资源的倾斜,磷化工产业竞争日益激烈。磷化工企业具有原材料成本占比大、生产连续、一次性投资高等特点,行业内各企业收益率低,向管理要效益,压缩生产成本已成为共同的追  相似文献   

7.
During the past few years, the increasing complexity of detergent formulations has required the analytical detergent chemists to devise many new and complicated separation schemes. This paper describes a method which allows the separation and quantitative determination of linear alkylbenzene sulfonate (LAS), ethoxylated alcohol sulfate (AES), alcohol sulfate (AS), free nonionic and amine oxide in detergent formulations. A combination of ion exchange, chemical separations, and gas chromatography is used in the described method. In addition to quantitating the types of “active” material listed, the ethylene oxide content of the ethoxylated alcohol sulfate and the homolog distribution of the alcohol hydrophobe in both the ethoxylated alcohol sulfate and the alcohol sulfate are obtained. This separation scheme is applicable to either liquid or powdered detergent formulations.  相似文献   

8.
Hall RG 《Chimia》2010,64(1-2):34-36
The properties and benefits offered by incorporating phosphorus into molecules are varied and numerous as shown by the many divisional research programs within Ciba-Geigy in the early eighties. This paper describes how a Central Research Group developed new materials in organophosphorous chemistry and identified new leads for life science applications.  相似文献   

9.
The African savanna ecosystem of the large mammals and primates was associated with a dramatic decline in relative brain capacity associated with little docosahexaenoic acid (DHA), which is required for brain structures and growth. The biochemistry implies that the expansion of the human brain required a plentiful source of preformed DHA. The richest source of DHA is the marine food chain, while the savanna environment offers very little of it. ConsequentlyHomo sapiens could not have evolved on the savannas. Recent fossil evidence indicates that the lacustrine and marine food chain was being extensively exploited at the time cerebral expansion took place and suggests the alternative that the transition from the archaic to modern humans took place at the land/water interface. Contemporary data on tropical lakeshore dwellers reaffirm the above view with nutritional support for the vascular system, the development of which would have been a prerequisite for cerebral expansion. Both arachidonic acid and DHA would have been freely available from such habitats providing the double stimulus of preformed acyl components for the developing blood vessels and brain. The n-3 docosapentaenoic acid precursor (n-3 DPA) was the major n-3-metabolite in the savanna mammals. Despite this abundance, neither it nor the corresponding n-6 DPA was used for the photoreceptor nor the synapse. A substantial difference between DHA and other fatty acids is required to explain this high specificity. Studies on fluidity and other mechanical features of cell membranes did not reveal a difference of such magnitude between even α-linolenic acid and DHA sufficient to explain the exclusive use of DHA. We suggest that the evolution of the large human brain depended on a rich source of DHA from the land/water interface. We review a number of proposals for the possible influence of DHA on physical properties of the brain that are essential for its function.  相似文献   

10.
对绿茶、葡萄籽和巴西大樱桃等23种植物提取物对酪氨酸酶的抑制作用以及其抗氧化能力(清除羟基自由基和超氧阴离子自由基的能力)进行了研究.实验结果表明,20种样品均表现出不同程度的酪氨酸酶抑制作用和抗氧化能力,其中绿茶、巴西大樱桃和葡萄籽提取物表现出极强的酪氨酸酶活性抑制率,且抑制活性远高于熊果苷;同时这3种植物提取物也表现出显著的清除羟基自由基和超氧阴离子自由基的能力,具有应用于美白化妆品的潜力.  相似文献   

11.
几千年的工艺美术历史为我们留下了许多宝贵的遗产,中国传统装饰是我们设计灵魂的源泉,剪纸、蜡染、刺绣等民间艺术也完全可以为我们的现代陶瓷装饰设计增光添彩。中国的现代陶瓷装饰文化馆的形成和设计风格的追求,都必须根据当前中国人自己的生活需求和审美需求,以及中国特有的文化模式来进行,设计出具有东方神韵和民族特色的陶瓷产品。1、中国传统装饰概述中国数千年的浩瀚历史,传统装饰艺术就像一颗颗嵌在艺术史项链上的璀璨明珠,  相似文献   

12.
Zero-order release of the physically dispersed active ingredients from the glassy hydrogels has been explained in the past on the basis of the case II transport of the penetrant medium into the matrix. This communication reports the zero-order release of the pendent chain-linked p-nitrobenzoic acid from glassy as well as swollen hydrogel matrices. This has been explained on the basis of the time-dependent diffusivity of p-nitrobenzoic acid resulting from the structural changes in the matrix accompanying the release. p-Nitrobenzoic acid would be released from these systems at a constant rate for periods of up to 5 months. Implants of this type in which the drug molecule is linked to the polymer backbone through the pendent chain are potentially promising systems for drug delivery at a constant rate for extended time periods.  相似文献   

13.
利用超声波预处理结合乙醇回流提取法从金银花中提取活性成分,通过响应面分析法设计实验,得到了较佳的提取工艺:超声波预处理30.9 min,乙醇的体积分数为73.7%,提取温度为68.5℃,每次提取2.1 h,提取2次,在此条件下绿原酸提取率达到88.39%。通过与阳性物质VC比较检验了提取物的功效,证明金银花提取物具有较好的体外抗氧化能力;通过对大肠杆菌、金黄色葡萄球菌、黑曲霉的抑制分析,证明金银花提取物具有良好的抑菌防腐能力。  相似文献   

14.
《Ceramics International》2022,48(7):8930-8959
In the context of the current global environmental paradigm, lithium zirconate-based materials (LZOs) are of great technological interest in the reduction of the carbon footprint. Due to their exceptional mechanical, thermal and chemical stability, high lithium atom density and outstanding tritium release behavior, LZOs have been studied as tritium breeding ceramics for fusion technology. Besides, given that they can selectively and reversibly absorb CO2 at high temperatures, LZOs could be used in the capture and industrial reuse of this gas. Moreover, in their most widespread use today, LZOs could be applied as nanocoatings on solid-state electrolytes and electrodes, constraining the formation of high resistive interfaces and slowing the evolution of dendrites, both in lithium-ion and solid-state batteries. Finally, there are some small contributions in the development of catalytic materials to produce biodiesel and air-hydrogen fuel cells based on LZOs, and also in the development of luminescent materials with photovoltaic applications. This article is the first review of the LZO system. It summarizes LZOs main applications and describes the latest advances in the technologies described above.  相似文献   

15.
段心定 《陶瓷》2021,(1):98-99
近年来,在社会经济快速发展的同时,人们的生活水平越来越高,在基本物质生活需求得以满足以后,对产品的质量提出了更高要求,希望能够在追求物质满足的同时,实现精神层面的满足在这种情况下,现代产品设计需要更好的提升自身的设计理念,将更多的传统文化融入其中,实现现代产品艺术性的提升。在我国传统的艺术形式中,陶瓷艺术作为其中的重要组成,对人们的日常生活产生了直接的影响,而其中所包含的各种有益元素,为现代产品设计理念的创新提供了可靠保障。因此,在当前的现代产品设计中,应该实现与陶瓷艺术的融合,从不同的角度对陶瓷艺术与现代产品设计理念融合进行分析,采取有效的措施,发挥出陶瓷艺术在推动现代产品设计中的作用,满足人们的精神文化需求。  相似文献   

16.
郝欣  于成龙 《江苏陶瓷》2006,39(2):15-17
现代社会意识和人们的审美心理发生了巨大的变化,对现代陶瓷艺术设计提出了严峻的要求。本文从现代生活方式角度出发,提出从陶瓷设计观念、造型、意蕴、装饰、材料及工艺技术等方面进行变革创新,以达到适应现代生活方式、审美趣味的目的。  相似文献   

17.
Miniaturization of plasma reactors has the potential of low power operation. In general, the electric field strength in the gap between two electrodes increases proportionate to inverse of the gap width, so that it is possible to overcome the first ionization potential of the gas with a low voltage. However, plasmas are extinguished primarily by recombination at the walls. Wall collisions are enhanced by the greater surface area to volume ratio in microchannels, which also increases proportionate to the inverse of the gap width. If the plasma were well mixed, then the plasma creation in the bulk would be balanced by extinction at the wall, providing no particular advantage with regard to low voltage/low power operation. However, the plasma is transferred from the bulk to the wall by ambipolar diffusion. If the operation of the plasma microreactor is essentially transient or batch, whether or not the reaction kinetics are comparable to or faster than ambipolar diffusion determines if there is a regime of operation in which a low voltage plasma discharge can generate a high yield of product. In this paper, this question is investigated with regards to the ozone formation reaction and a particular design of a microchannel plasma reactor, with parameters so chosen to arguably achieve low voltage operation. The focus of this paper is the simulation of the kinetics of the plasma reactions leading to ozone formation, which shows a time to completion that is comparable (10?2 s) or faster than the estimate of ambipolar diffusion time at these length scales. Preliminary results of a microchip reactor are consistent with this prediction.  相似文献   

18.
红景天活性成分的提取工艺及其美容功效研究   总被引:1,自引:3,他引:1  
利用水提法从植物红景天的根中提取活性成分,通过四因素三水平正交试验得到了较佳的提取工艺:红景天根粉碎过60目筛、料液(红景天根和去离子水)质量比1:10、提取温度100℃、提取时间10 min.提取液中的活性成分红景天苷和总黄酮的含量分别用高效液相色谱法和三氯化铝比色法测定.通过与阳性物质对照比较检验了提取液的功效,证明红景天提取液具有体外抗氧化和抑制酪氨酸酶的能力,可以作为延缓衰老和美白化妆品添加剂.  相似文献   

19.
Using a scenario format, this paper first reviews the nature of chemical process design, showing that designers quickly make major decisions with minimal information and constantly revise their strategy to solve a problem. To automate this activity on a computer will require models of the process being created at several levels of abstraction as well as models that capture the beliefs of the modeler about the abilities of himself, others and the aids available and models of strategies for complex problem solving.The second section of the paper extensively reviews current expert system concepts, illustrating each of them with design examples. We argue that expert systems are knowledge based. We describe many of the control strategies used in today's systems, and also consider different problem representations -- rules, logic and frames -- and indicate when each might be preferred. A last section gives our views on what will be involved in creating a future expert system for design.  相似文献   

20.
李品  冯雪迎 《陶瓷研究》2007,22(2):57-58
在现代陶瓷设计当中,设计的主要因素主要是适应现代人的生活方式和时代审美旨准,因为现代人的工作和生活方式比较多元化,所以形成了现代陶瓷设计多向思维和定位。这就要求我们对其中的共性和个性的认知和把握,它在很大程度上决定设计的成功与否。针对当前的陶瓷市场上有部分的陶瓷产品在材质器型和花面上存在着比较雷同或不足的地方,开发和设计更多适应人们生活的陶瓷产品是陶瓷设计者应该进行反思考。  相似文献   

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