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排序方式: 共有1686条查询结果,搜索用时 234 毫秒
31.
Garrett BC Dixon DA Camaioni DM Chipman DM Johnson MA Jonah CD Kimmel GA Miller JH Rescigno TN Rossky PJ Xantheas SS Colson SD Laufer AH Ray D Barbara PF Bartels DM Becker KH Bowen KH Bradforth SE Carmichael I Coe JV Corrales LR Cowin JP Dupuis M Eisenthal KB Franz JA Gutowski MS Jordan KD Kay BD Laverne JA Lymar SV Madey TE McCurdy CW Meisel D Mukamel S Nilsson AR Orlando TM Petrik NG Pimblott SM Rustad JR Schenter GK Singer SJ Tokmakoff A Wang LS Wettig C Zwier TS 《Chemical reviews》2005,105(1):355-390
32.
C. C. Duncan D. M. Yermanos J. Kumamoto C. S. Levesque 《Journal of the American Oil Chemists' Society》1974,51(12):534-536
A rapid ethanolysis procedure for preparing jojoba wax for gas liquid chromatographic analysis is described. The wax esters
are hydrolyzed by refluxing 4 drops of jojoba wax in 5% HCl in anhydrous ethanol in a test tube. The resulting fatty acid
ethyl esters and fatty alcohols are separated and quantitated by a single gas liquid chromatographic run. Analysis of duplicate
samples by this procedure gives essentially the same results as a procedure which requires 10 times more sample and reagents
and considerably more time. 相似文献
33.
34.
Kathleen Menzies Duncan Birrell Gordon Dunsire 《New Review of Information Networking》2013,18(2):92-140
This article reports on the key findings and implications of the Joint Information Systems Committee (JISC)-funded Online Catalogue and Repository Interoperability Study (OCRIS), a 3-month project which investigated the interoperability of Online Public Access Catalogues (OPACs) and Institutional Repositories (IRs) within UK universities. A series of detailed recommendations enumerate some of the ways in which they might begin to develop and support an interoperable systems landscape to the benefit of all key stakeholders. The project combined quantitative and qualitative research methods including an online questionnaire distributed to staff within 85 universities, desk research, and two case studies conducted at the Universities of Cambridge and Glasgow. 相似文献
35.
Two high‐head dams on the Elwha River in Washington State (USA) have changed the migratory patterns of resident and anadromous fish, limiting Pacific salmon to the lower 7.9 km of a river that historically supported large Pacific salmon runs. To document the effects of the dams prior to their removal, we measured carbon and nitrogen stable isotope ratios of primary producers, benthic macroinvertebrates, and fish, and water chemistry above, between and below the dams. We found that δ15N was significantly higher in fish, stoneflies, black flies, periphyton and macroalgae where salmon still have access. Fish and chloroperlid stoneflies were enriched in δ13C, but the values were more variable than in δ15N. For some taxa, there were also differences between the two river sections that lack salmon, suggesting that factors other than marine‐derived nutrients are structuring longitudinal isotopic profiles. Consistent with trophic theory, macroalgae had the lowest δ15N, followed by periphyton, macroinvertebrates and fish, with a range of 6.9, 6.2 and 7.7‰ below, between, and above the dams, respectively. Water chemistry analyses confirmed earlier reports that the river is oligotrophic. Phosphorous levels in the Elwha were lower than those found in other regional rivers, with significant differences among regulated, unregulated and reference sections. The removal of these dams, among the largest of such projects ever attempted, is expected to facilitate the return of salmon and their marine‐derived nutrients (MDN) throughout the watershed, possibly altering the food web structure, nutrient levels and stable isotope values that we documented. Published in 2010 by John Wiley & Sons, Ltd. 相似文献
36.
Current techniques for transforming unforgeable signature schemes (the forged message has never been signed) to strongly unforgeable ones (the forged message could have been signed) require supplementary components to be added onto the original key pairs of the schemes. In addition, some of them can only be applied to a certain type of signature schemes. In this paper, we propose a new generic transformation technique which converts any unforgeable signature scheme into a strongly unforgeable one without modifying any component in the original key pair. This makes our technique especially compatible for practical use. Our technique is based on strong one-time signature schemes. We show that they can be constructed efficiently from any one-time signature scheme that is based on one-way functions. The performance of our technique also compares favorably with that of current ones. Besides, it is shown in this paper that our transformation can further be applied to schemes satisfying only a weak variant of unforgeability without any further modification. Furthermore, our technique can also be used for constructing strongly unforgeable signature schemes in other cryptographic settings which include certificateless signature, identity-based signature, and several others. To the best of our knowledge, similar extent of versatility is not known to be supported by any of those comparable techniques. Finally and of independent interest, we show that our generic transformation technique can be modified to an on-line/off-line signature scheme, which possesses a very efficient signing process. 相似文献
37.
Yan Wang Kwei-Jay Lin Duncan S. Wong Vijay Varadharajan 《Service Oriented Computing and Applications》2009,3(2):129-146
In service-oriented computing (SOC) environments, service clients interact with service providers for services or transactions.
From the point view of service clients, the trust status of a service provider is a critical issue to consider, particularly
when the service provider is unknown to them. Typically, the trust evaluation is based on the feedback on the service quality
provided by service clients. In this paper, we first present a trust management framework that is event-driven and rule-based.
In this framework, trust computation is based on formulae. But rules are defined to determine which formula to use and what
arguments to use, according to the event occurred during the transaction or service. In addition, we propose some trust evaluation
metrics and a formula for trust computation. The formula is designed to be adaptable to different application domains by setting
suitable arguments. Particularly, the proposed model addresses the incremental characteristics of trust establishment process.
Furthermore, we propose a fuzzy logic based approach for determining reputation ranks that particularly differentiates new
service providers and old (long-existing) ones. This is further incentive to new service providers and penalize poor quality
services from service providers. Finally, a set of empirical studies has been conducted to study the properties of the proposed
approaches, and the method to control the trust changes in both trust increment and decrement cases. The proposed framework
is adaptable for different domains and complex trust evaluation systems.
相似文献
Vijay VaradharajanEmail: |
38.
Farrugia Russell Portelli Barnaby Grech Ivan Camilleri Duncan Casha Owen Micallef Joseph Gatt Edward 《Microsystem Technologies》2022,28(6):1451-1465
Microsystem Technologies - The maximum scan angle amplitude of resonating micro-mirrors, intended for micro-projection display applications is limited by air damping. Three-dimensional transient... 相似文献
39.
Xiaoying Cheng Xuyang Cao Zhenyu Wu Zhiping Ying Duncan Camilleri Xudong Hu 《Advanced Engineering Materials》2023,25(19):2300341
Carbon fiber-reinforced polymer (CFRP) materials are widely applied in various areas as key structure components. The structural health monitoring of the CFRP components is crucial to prevent catastrophic failure. However, the nonplane surfaces of CFRP components hinder the attaching of monitoring sensors with hard substrates. Therefore, the substrate conditions for sensor preparation are mainly considered in this study. To adapt the proposed sensors to the curved substrate, including nondevelopable surfaces, electrospinning method is used to prepare conformal piezoresistive fiber films, in which polymethyl methacrylate is served as the matrix and carbon nanotubes are utilized as the conductive filler. The piezoresistive fibers covered on CFRP substrates have a gauge factor up to 207.95 and can response to the strain less than 0.05%. Moreover, the sensor also has high durability and the ability to follow the dynamic excitation signals with as high as 50 Hz. 相似文献
40.
GH Gilbert RP Duncan MW Heft TA Dolan WB Vogel 《Canadian Metallurgical Quarterly》1998,36(7):988-1001
OBJECTIVES: An understanding of the validity and usefulness of self-reported measures (as distinct from clinically determined measures) of oral health is emerging. These self-reported measures include self-rated oral health (SROH). Three objectives were to: (1) describe self-rated oral health in dentate adults, (2) quantify associations between self-rated oral health and other measures of oral health (oral disease and tissue damage, pain and discomfort, functional limitation, and disadvantage), and (3) assess the construct validity of a model of oral health proposed herein. METHODS: The Florida Dental Care Study is a longitudinal study of oral health, which included at baseline 873 subjects who had at least one tooth, were 45 years or older, and who participated for an interview and clinical examination. RESULTS: The prevalence of self-rated oral health decrements was substantial; approximately one fourth of subjects reported their oral health as only fair or poor. Bivariate and multivariate results provided consistent evidence of the construct validity of the proposed model of oral health. Additionally, the salience of one measure of dental appearance suggests that persons may use esthetic cues when rating their oral health. CONCLUSIONS: The proposed multidimensional model of oral health has construct validity. Self-rated oral health is affected by oral disease and tissue damage, oral pain and discomfort, oral functional limitation, and oral disadvantage. These self-reported measures and the proposed model should provide useful information for dental care effectiveness research. General health status has been disaggregated into the "physical" and the "mental;" an additional separation into the "oral" aspects of health seems warranted. 相似文献