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排序方式: 共有1623条查询结果,搜索用时 31 毫秒
121.
Fuangswasdi A Krajangpan S Sabatini DA Acosta EJ Osathaphan K Tongcumpou C 《Water research》2007,41(6):1343-1349
Mixtures of anionic and cationic surfactants exhibit synergistic behavior as evidenced by low critical micelle concentrations (CMC) of the mixed system, increased surface activity, and improved detergency performance. The adsorption of a single-head anionic surfactant, sodium dodecyl sulfate (SDS), in mixture with a twin-head cationic surfactant, pentamethyl-octadecyl-1,3-propane diammonium dichloride (PODD), showed synergism of adsorption onto silica when present at a mixing ratio of 1:3 (cationic-rich), and also demonstrated lower surfactant desorption with water flushing of columns packed with the surfactant-modified media. In addition, the proportion of the mixed surfactants in the admicelles moved from the initial ratio of 1:3 towards equimolar after rinsing the surfactant-modified silica absorbent. The retardation of organic solutes passing through columns packed with modified-silica adsorbent increased nominally three fold for silica modified with mixed surfactants versus single surfactants (retardation factors increase from 4.0 to 12.8 for styrene and from 32.1 to 90.2 for ethylcyclohexane for single and mixed surfactants, respectively). Thus, this study demonstrates that mixed surfactant systems more effectively modified the silica surface than single surfactant systems both in terms of enhanced retardation of organic solutes and in terms of reduced surfactant desorption. 相似文献
122.
本文以高级脂肪醇为起始原料,合成了一种新型的含硫阳离子表面活性剂——硫鎓盐(Sulfine)产物的结构与纯度由IR、'H-NMR、TLC、EA等法加以分析鉴定。同时对产物的物理化学性能进行了研究。结果表明:此类阳离子表面活性剂的性能优良。 相似文献
123.
《Energy Policy》2015
After a stable or declining real trend that persisted for more than half a century, Australian retail electricity prices have experienced a substantial increase, in real terms, since 2007. This has mainly been driven by increases in the cost of electricity distribution and to a lesser degree in the cost of electricity generation. Reducing greenhouse gas emissions, which is a bipartisan political goal in Australia, will likely deliver further increases in generation costs due to the expected higher cost of low emission technology. Participating in global negotiations on emission reduction targets and designing efficient policy mechanisms have been a major focus of governments over the last several decades. In contrast, managing distribution system costs has received less attention. While there were a number of factors which drove historical increases in distribution costs, management of peak demand growth could help contain or reduce the extent to which consumers, particularly households, experience further increases in distribution costs. The paper demonstrates how different combinations of carbon price and peak demand scenarios could impact future residential and industrial retail electricity prices to 2050 and discusses some behavioural and technological solutions to manage peak demand and potential barriers to their deployment. 相似文献
124.
《全球能源互联网(英文)》2021,4(1):69-80
Electric system planning with high variable renewable energy (VRE) penetration levels has attracted great attention world-wide. Electricity production of VRE highly depends on the weather conditions and thus involves large variability, uncertainty, and low-capacity credit. This gives rise to significant challenges for power system planning. Currently, many solutions are proposed to address the issue of operational flexibility inadequacy, including flexibility retrofit of thermal units, inter-regional transmission, electricity energy storage, and demand response (DR). Evidently, the performance and the cost of various solutions are different. It is relevant to explore the optimal portfolio to satisfy the flexibility requirement for a renewable dominated system and the role of each flexibility source. In this study, the value of diverse DR flexibilities was examined and a stochastic investment planning model considering DR is proposed. Two types of DRs, namely interrupted DR and transferred DR, were modeled. Chronological load and renewable generation curves with 8760 hours within a whole year were reduced to 4 weekly scenarios to accelerate the optimization. Clustered unit commitment constraints for accommodating variability of renewables were incorporated. Case studies based on IEEE RTS-96 system are reported to demonstrate the effectiveness of the proposed method and the DR potential to avoid energy storage investment. 相似文献
125.
P. S. Niranjan Ratna Shukla Santosh K. Upadhyay 《Journal of surfactants and detergents》2012,15(1):53-57
The aggregation behaviour of two cationic surfactants, viz. cetyl trimethyl ammonium bromide (CTAB) and N-cetyl pyridinium
chloride (CPC), in different concentrations of water-soluble polyacrylamide has been studied in alkaline medium by electrical
conductivity and surface tension measurements. A decrease in the critical micelle concentration (CMC) of the surfactant with
an increase in polymer content in the mixture was observed. The thermodynamic and surface parameters have been determined
and discussed. The results indicate that micellisation becomes more favourable at higher polymer content. 相似文献
126.
大古2井超深复杂井钻井液技术 总被引:1,自引:0,他引:1
大古2井为大涝坝构造山前构造的一口重点探井,完钻井深为6 702 m。该井二开(φ311.2 mm)裸眼井段长(2 500~5 300 m),钻遇多套高压盐水层和石膏层;三开(φ215.9 mm,5 300~6 552.53 m)存在多套压力体系,地层渗透性强,高密度条件下压差卡钻的风险大。现场采用阳离子乳液聚合物钻井液,并根据不同井下复杂情况加强钻井液性能维护处理,解决了遇阻卡钻和地层出盐水等复杂问题;通过添加超低渗透处理剂和屏蔽暂堵剂,强化对地层的封堵,解决了三开施工中出现的压差卡钻风险,保证了现场安全施工。 相似文献
127.
阳离子试剂是一类重要的有机化合物,由于具有阳荷性,与阴离子化合物或阴荷性物质可以发生较强的电性作用。近年来,改善纺织品染色性能,特别是提高染料上染率、固色率和色牢度成为大家关注的一个问题,应用阳离子试剂可以大大改善这些染色性能,但是也存在许多困难。该文系统地介绍了阳离子试剂的结构、类别和性能,分析了它们的结构和功能性的关系,介绍了阳离子试剂用于纤维改性和提高染料染色牢度的作用和理论,为合理选用阳离子试剂提供了理论依据。文章还全面介绍了纤维阳离子改性的工艺,加工方法和主要工艺条件,介绍了染色后固色工艺,指出了合理选用阳离子试剂和加工工艺的重要性。该文最后还展望了阳离子试剂应用前景,特别强调深入进行阳离子试剂的开发、应用理论和工艺研究的重要价值,指出这是一条发展低碳经济,生态染色的有效途径。 相似文献
128.
In order to stay competitive in the global economy which provides clients with a wide range of potential suppliers, businesses offer highly parameterizable products with increasingly shorter delays. We propose a simulation approach that allows businesses to estimate their capacity to honor promised delivery dates in a make-to-order environment. This paper presents a framework as well as the needs that arise when considering client profiles in a modeling and simulation approach. We focus here on our methodology for representing and generating client behaviors, as well as on the demand and supply simulation approach and environment developed to conduct experiments on delivery time promising policies and delivery capacity. 相似文献
129.
Does an electricity market which has been restructured to foster competition provide greater opportunities for demand response than a traditional regulated utility industry? The experiences of the restructured Electric Reliability Council of Texas (ERCOT) market over the past eight years provide some hope that it is possible to design a competitive market which will properly value and accommodate demand response. While the overall level of demand response in ERCOT is below the levels enjoyed prior to restructuring, there have nonetheless been some promising advances, including the integration of demand-side resources into competitive markets for ancillary services. ERCOT's experiences demonstrate that the degree of demand participation in a restructured market is highly sensitive to the market design. But even in a market which has been deregulated to a large degree, regulatory intervention and special demand-side programs may be needed in order to bolster demand response. 相似文献
130.
Imad Jabir 《Energy Economics》2001,23(6):4126
Tremendous political pressure is being exerted on the US government by different political parties to diversify its sources of foreign oil supplies by switching from the reliance on OPEC's oil to that originating from non-OPEC nations. Without a doubt, such a shift would adversely impact the market share of some OPEC members, particularly Saudi Arabia, Venezuela and Nigeria. These countries should therefore consider seriously the negative impact of this scenario and consequently formulate individual or joint production policies aiming at protecting their oil market share. To help OPEC achieve this objective, there is a need to estimate the demand function of US oil imports. This paper proffers an estimate of such a function, taking into account, among other variables, the impact of US Strategic Petroleum Reserve (SPR). 相似文献