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1.
微乳液在萃取分离中的研究进展   总被引:4,自引:0,他引:4  
周富荣  杜金萍 《现代化工》2006,26(12):17-20
概述了微乳液的定义及其特性,介绍了微乳液作为分离介质萃取分离金属离子、有机化合物及生化物质等方面的研究进展。指出微乳液萃取过程中不存在毒性试剂,且具有分离速度快、萃取效率高、操作方便、油相可以反复利用等优点,具有良好的工业应用前景。  相似文献   

2.
分别概述了越南、泰国、印度尼西亚、新加坡、马来西亚和菲律宾等东南亚各国的化妆品市场的现状和特点。东南亚国家的化妆品市场各不相同,虽然都受到了经济危机的影响,但是很多国家的化妆品销售仍然呈上升趋势。  相似文献   

3.
微反应器内聚合物合成研究进展   总被引:3,自引:3,他引:0       下载免费PDF全文
骆广生  王凯  王佩坚  吕阳成 《化工学报》2014,65(7):2563-2573
微反应器作为化学工程学科的前沿和热点方向,逐渐成为聚合物合成的新装备、新工艺与新产品开发的重要平台,得到学术界和产业界的广泛关注。微反应器可实现可控的多相微尺度流动,能够强化聚合反应中的混合、传质和传热过程,严格控制反应时间,实现反应单元的模块化组合。与传统搅拌反应器相比,这些特点使得微反应器在控制聚合物分子量分布,简化反应环境,提高反应选择性,调节聚合物分子结构和宏观形貌等方面展现出了一定优势。本文全面综述了聚合物合成微反应器理论和技术的研究进展,并在新过程和新产品开发、反应动力学测量、微尺度基础研究和反应器放大等方面进行了展望。  相似文献   

4.
In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO2 L–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.  相似文献   

5.
我国食品的农药污染问题   总被引:71,自引:2,他引:69  
综述了我国食品中的有机氯和有机磷农药残留现状,分析了污染原因,提出了防止对策,并对我国食品农药残留标准进行了评述。  相似文献   

6.
高效液相色谱法分析化妆品中微量成分的研究进展   总被引:1,自引:0,他引:1  
高尚芬 《日用化学工业》2006,36(6):379-383,400
综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。  相似文献   

7.
通过研究区钻井岩心、野外露头裂缝系统观测与统计,岩心薄片观察分析,对鄂尔多斯盆地中西部上三叠统裂缝系统的分布特征及成因进行了分析。鄂尔多斯经历了多期构造运动,不同期次形成的裂缝系统在盆地内部不同构造单元表现出不一致性。研究区处在鄂尔多斯几个构造单元接触地带,构造裂缝为主要的裂缝类型,其分布在区域上表现出多样性。上三叠统主要发育NEE、NNW、NE、NW四组裂缝系统,其中为NNE向裂缝和NW向裂缝形成于燕山期,NNW向裂缝和NE向裂缝形成于喜山期。  相似文献   

8.
9.
外商来华投资存在的主要问题是:①技术引进效果不十分理想;②无力维持中方控股地位和正常资本收益;③挤占和垄断行业市场;④严重冲击我国的品牌;⑤外商投资对我国环境产生较大的污染;⑥不能充分保证中方员工的正当利益。介绍了我国化工领域利用外资中存在的问题,对我国更好地利用外资提出了对策及建议。  相似文献   

10.
Mikko Hupa 《Fuel》2005,84(10):1312-1319
More than half of the recent large-scale FBC installations are designed to burn more than one fuel. Especially the use of various biofuels—as such or besides conventional fuels—is becoming more and more common in the new FBC projects. It is a major challenge to be able to understand and predict the behavior of the FBC system when co-firing of different fuels in different proportions. This paper reviews some of the recent research on the fuels interaction in FBC. It is shown that factors such as flue gas emissions, fouling tendency or bed sintering tendency are seldom simple linear functions of the fuel mixture. Rather, non-linear relationships of some kind are much more common. The examples in the paper deal with gaseous emissions in co-firing of wood and coal, and superheater fouling in co-firing of biomass based fuels with very different ashes.  相似文献   

11.
结晶作为一种传统的分离和提纯工艺,广泛运用于医药、化工、材料等领域。随着对结晶工艺的深入研究和对晶体产品质量越来越高的要求,结晶不再仅仅用于物质的分离和提纯,更重要的是根据产品功能的需要,制备特定结构的晶体。作为结晶的重要组成部分,溶析结晶因其操作简单、能耗相对较低、适用于热敏性物质等优势受到了广泛的关注。本文从溶析结晶相较于其他溶液结晶的不同点出发,重点介绍了溶析结晶热力学、溶析结晶动力学和工艺过程的研究,以及与溶析结晶相关的超临界流体技术和球形结晶技术。溶析结晶热力学关注了溶解度的测定方法和如何通过相图来确定合适的操作条件;溶析结晶动力学,详细描述了间歇、连续溶析结晶动力学模型的建立;工艺过程的研究,包括溶析剂与含有待结晶物质混合、结晶过程的控制和优化。同时本文对溶析结晶目前存在的问题进行了总结,并对未来的发展作了展望。  相似文献   

12.
溶液丁苯连续聚合凝胶抑制技术进展   总被引:3,自引:0,他引:3  
王军  刘青 《弹性体》1999,9(2):49-52
介绍了溶液丁苯连续聚合过程中凝胶形成的原因,综述了国外对抑制凝胶形成的技术进展。提出了我国发展溶液丁苯连续聚合抑凝技术的一些建议,并简介了目前在这方面的研究情况  相似文献   

13.
目前,页岩气藏的开发已经成为全球能源开发的热点,而中国页岩气藏开发还处于初期阶段,其多元化的发展面临着严峻的挑战。井壁失稳问题经常会出现在钻井作业中,而页岩气藏开发中井壁稳定问题显得更为突出。井壁失稳会导致卡钻、井眼报废等一系列问题,给钻井工程带来巨大损失,因此全面了解页岩气藏井壁稳定性研究进展十分重要。本文从力学、化学及力化耦合三方面出发,综合国内外研究进展,比较全面地对井壁稳定性研究进行了整理和归纳,以便更好的了解页岩气藏井壁稳定性的研究进展,为实际生产和工程应用提供参考。  相似文献   

14.
Biocatalysis using oxygenase or desaturase enzymes has the potential to add value to native fats and oils by adding oxygen, hydroxyl groups, or double bonds to create regio- and/or stereospecific products. These enzymes are a subset of the large class of oxidoreductase enzymes (from EC subgroups 1.13 and 1.14) involved with biological oxidation and reduction. In vitro biocatalytic processing using these enzymes is hampered by the high cost of the stoichiometric cofactors. This article reviews recent progress in developing in vitro redox enzyme biocatalysis for commercial-scale syntheses. Coenzyme recycling and electrochemical redox cycling as methods for cofactor regeneration are described and commercial applications indicated. Direct charge transfer without use of mediators is described as the cleanest way of introducing the reducing power into the catalytic cycle. Our electrochemically driven cytochrome P450cam bioreactor is discussed as an example of direct charge transfer to a redox protein. Site-directed mutagenesis in the active site of the P450cam monooxygenase greatly improved performance for the conversion of the nonnative substrate, styrene to styrene oxide. This epoxidation reaction was also shown to give a single product (styrene oxide) in the bioelectrochemical reactor when the diatomic oxygen co-substrate was managed properly. Certain commercial equipment, instruments, and materials are identified in this paper to specify adequately the experimental procedure. In no case does such identification imply recommendation or endorsement by the National Institute of Standards and Technology nor does it imply that the material or equipment is necessarily the best available for the purpose.  相似文献   

15.
Cancer is one of the leading causes of death worldwide. Conventional therapies, including surgery, radiation, and chemotherapy have achieved increased survival rates for many types of cancer over the past decades. However, cancer recurrence and/or metastasis to distant organs remain major challenges, resulting in a large, unmet clinical need. Oligonucleotide therapeutics, which include antisense oligonucleotides, small interfering RNAs, and aptamers, show promising clinical outcomes for disease indications such as Duchenne muscular dystrophy, familial amyloid neuropathies, and macular degeneration. While no approved oligonucleotide drug currently exists for any type of cancer, results obtained in preclinical studies and clinical trials are encouraging. Here, we provide an overview of recent developments in the field of oligonucleotide therapeutics in oncology, review current clinical trials, and discuss associated challenges.  相似文献   

16.
深入分析了合成洗涤剂行业的共性问题,市场环境的变化为合成洗涤剂行业的发展带来了三大契机.面对机遇,企业应该审时度势,采取迅速见效的策略,从根本上打造企业的竞争力.同时指出,企业要面向市场,要创新求变.并针对当前企业所存在的问题,提出了一些应对措施.  相似文献   

17.
1999—2000年国外有机硅进展   总被引:7,自引:1,他引:6  
根据1999年7月-2000年6月国外期刊中相关文献资料,简述了国外有机硅工业的生产和市场动向,着重介绍了国外几家大公司的动态及其研制开发的部分有机硅新产品。  相似文献   

18.
注塑件熔接缝研究进展   总被引:6,自引:0,他引:6  
综述了注塑过程中熔接缝形成的组织结构及其力学性能研究的进展 ,讨论了熔接缝的特点 ,着重阐述了熔接缝强度的影响因素、研究的技术手段和提高熔接缝强度的措施 ,以及熔接缝加工参数优化与数值模拟技术。  相似文献   

19.
与世界同类催化剂相比,N 型催化剂在活性、定向性、活性寿命等方面有独到的特性,其聚合产品的耐老化性、热稳定性和耐辐射性等方面都优于其他同类催化剂。介绍了我国聚丙烯催化剂的开发应用情况,着重阐述了N 型催化剂近年来的发展概况、特性及应用情况,对现有聚丙烯装置的改进提出了建议。  相似文献   

20.
杀菌剂生物筛选离体活体兼顾的重要性   总被引:5,自引:0,他引:5  
新合成的以金核霉素结构改造为主的数十种化合物,经多种病原菌的离体抑菌活性测定和盆栽防治效果测定,谈谈在杀菌剂生物筛选中采用离体活体测定相兼顾的重要性.  相似文献   

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