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排序方式: 共有506条查询结果,搜索用时 31 毫秒
31.
The electrical conductivity of ceria thin films (epitaxial as well as dense and porous nanocrystalline) is investigated in dry and wet atmosphere at temperatures below 500 °C. For the epitaxial and the fully dense nanocrystalline samples, no significant differences can be observed between dry and wet conditions. In marked contrast, the nanocrystalline porous films obtained via spin coating exhibit a considerable enhancement of the protonic conductivity below 300 °C in wet atmosphere. This outcome reveals that the residual open mesoporosity plays the key role for the enhancement of the proton transport at low temperatures and not the high density of grain boundaries. The quantitative analysis of the various pathways, along which the proton transport can take place, indicates that the observed proton conduction can arise not only from bulk water adsorbed in the open pores but also from the space charge zones on the water side of the water/oxide interface. 相似文献
32.
Mona Anvari Mohammad Saidi Mehrabad Ali Azadeh Morteza Saberi 《The International Journal of Advanced Manufacturing Technology》2010,46(9-12):1059-1069
This study proposes a nonparametric method based on adaptive neural network (ANN) technique for measuring efficiency of decision making units (DMUs) in one period case as a complementary tool for the ANN-based efficiency methods in the previous studies. In previous studies, there are needed to have large volume of data, and so the proposed method in this study is more applicable because it can be used for the cases which have no historical data. In fact, a limitative weakness of the ANN-based efficiency methods about applying them for these cases is removed. So, it can be a competitive method to the other common tools for measuring efficiency. By noting the importance of flexible manufacturing system, this study presents a decision-making model for optimization of operators’ allocation in cellular manufacturing system by computer simulation. The methodology is illustrated through its application on a previously reported dataset. It was found out that ANN provides more robust results and identifies more efficient units than the conventional methods since better performance patterns are explored. 相似文献
33.
In this study, environmentally friendly polyester based polyurethane dispersions (PUDs) were synthesized using various combinations of isophthalic acid, adipid acid and maleic anhydride (IPA-AA-MA). A triangular empirical model was employed to optimize total number of experiments for optimal performance of polyurethane dispersions. In addition to PUDs, polyurethane/acrylate hybrid dispersions (PU/AC) were synthesized using graft copolymerization method to enhance the performance/properties of PUDs and for potential cost benefit. 相似文献
34.
Buhusi Catalin V.; Aziz Dyana; Winslow David; Carter Rickey E.; Swearingen Joshua E.; Buhusi Mona C. 《Canadian Metallurgical Quarterly》2009,123(5):1102
In many species, interval timing behavior is accurate—appropriate estimated durations—and scalar—errors vary linearly with estimated durations. Whereas accuracy has been previously examined, scalar timing has not been clearly demonstrated in house mice (Mus musculus), raising concerns about mouse models of human disease. The authors estimated timing accuracy and precision in C57BL/6 mice, the most used background strain for genetic models of human disease, in a peak-interval procedure with multiple intervals. Both when timing 2 intervals (Experiment 1) or 3 intervals (Experiment 2), C57BL/6 mice demonstrated varying degrees of timing accuracy. An important finding was that, both at the individual and group levels, their precision varied linearly with the subjective estimated duration. Further evidence for scalar timing was obtained using an intraclass correlation statistic. This is the first report of consistent, reliable scalar timing in a sizable sample of house mice, thus validating the peak-interval procedure as a valuable technique, the intraclass correlation statistic as a powerful test of the scalar property, and the C57BL/6 strain as a suitable background for behavioral investigations of genetically engineered mice modeling disorders of interval timing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
The redesign of alleyways located in commercial districts is typically undertaken to effect economic development and to develop a sense of community and a sense of place through these spaces. An investigation of a recently renovated alley in the Hollywood neighbourhood of Los Angeles, CA was conducted to assess aspects of the efficacy of this project—namely, how and by what magnitude use of the alley differed from use of an unconverted alley. Behavioural observations carried out in the East Cahuenga Pedestrian Alley and a nearby control alley revealed considerable differences in use. Findings include that nearly 90% of all recorded activity occurred in the redesigned alley and the majority of this was pedestrian- and dining-related, while control alley activity was heavily transportation- and work-oriented. Results substantiate claims that alley landscape redesign revitalises social life in commercial district alleys. 相似文献
36.
R. O. Feuge Mona Brown J. L. White 《Journal of the American Oil Chemists' Society》1972,49(11):672-673
A glycoside ester product was prepared by the transglycosylation of starch and glycerol, which yielded a mixture of 2,3-dihydroxypropyl-α-D-glucopyranoside
and other glycerol glycosides, followed by interesterification of the crude glycerol glycosides with a mixture of mono-, di-
and tripalmitin. The purified reaction product, consisting of ca. 77% glycerol glycoside palmitates, 14% palmitins and 9%
free palmitic acid, was found to be extremely effective in lowering the interfacial tension between cottonseed oil and water—a
0.04% concentration in the oil phase lowering the interfacial tension to 1.3 dynes/cm.
ARS, USDA. 相似文献
37.
Mona Hosseini-Sarvari 《Catalysis Letters》2011,141(2):347-355
Abstract
An eco-friendly catalytic amount (10 mol%) of nanocrystalline ZnO has been explored in the synthesis of new series of ferrocenyl aminophosphonic esters by a three-component reaction of ferrocene carbaldehyde, an amine, and a dialkyl phosphate. The nano ZnO catalyzed the selective synthesis of ferrocenyl aminophosphonates and no intermediate formation of either an imines or α-hydroxy phosphonate were observed. This is one of the fundamental aspects in green chemistry for simple experimental and product isolation protocol. 相似文献38.
Bahman Zarenezhad Mona Mottahedin Ali Haghighi Asl 《Korean Journal of Chemical Engineering》2011,28(3):949-953
Accurate prediction of phase equilibria regarding CH4 replacement in hydrate phase with high pressure CO2 is an important issue in modern reservoir engineering. In this work we investigate the possibility of establishing a thermodynamic
framework for predicting the hydrate equilibrium conditions for evaluation of CO2 injection scenarios. Different combinations of equations of state and mixing rules are applied and the most accurate thermodynamic
models at different CO2 concentration ranges are proposed. 相似文献
39.
Mona Ibrahim Karine Groenen Serrano Laure Noe Ccile Garcia Marc Verelst 《Electrochimica acta》2009,55(1):155-158
Nanoparticles of magnetites (Fe3O4) are synthesized with a new process based on electro-precipitation in ethanol medium. A mechanism pathway is proposed consisting of a Fe(OH)3 precipitation followed by the reduction of iron hydroxide to magnetite in the presence of hydroxyl ions which are generated at the cathode. 相似文献
40.