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排序方式: 共有1367条查询结果,搜索用时 8 毫秒
1.
Intensive fertilizer use has led to nitrate contamination of groundwater in many areas. This article examines the possibility of removing nitrates through the construction of artificial wetlands. A pilot study conducted in Denmark has found that the method is effective and economical, at least for small waterworks, though further treatment is necessary before an acceptable microbiological water quality is attained. 相似文献
2.
We determine the exact power of two-prover interactive proof systems introduced by Ben-Or, Goldwasser, Kilian, and Wigderson (1988). In this system, two all-powerful noncommunicating provers convince a randomizing polynomial time verifier in polynomial time that the inputx belongs to the languageL. We show that the class of languages having tow-prover interactive proof systems is nondeterministic exponential time.We also show that to prove membership in languages inEXP, the honest provers need the power ofEXP only.The first part of the proof of the main result extends recent techniques of polynomial extrapolation used in the single prover case by Lund, Fortnow, Karloff, Nisan, and Shamir.The second part is averification scheme for multilinearity of a function in several variables held by an oracle and can be viewed as an independent result onprogram verification. Its proof rests on combinatorial techniques employing a simple isoperimetric inequality for certain graphs: 相似文献
3.
This study provides a meta-analysis of research on the associations between relationship conflict, task conflict, team performance, and team member satisfaction. Consistent with past theorizing, results revealed strong and negative correlations between relationship conflict, team performance, and team member satisfaction. In contrast to what has been suggested in both academic research and introductory textbooks, however, results also revealed strong and negative (instead of the predicted positive) correlations between task conflict, team performance, and team member satisfaction. As predicted, conflict had stronger negative relations with team performance in highly complex (decision making, project, mixed) than in less complex (production) tasks. Finally, task conflict was less negatively related to team performance when task conflict and relationship conflict were weakly, rather than strongly, correlated. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
H Lindemann 《Canadian Metallurgical Quarterly》1993,141(5):392-394
The defective regulation of the secretory chloride channel and the accelerated rate of sodium absorption in the airway epithelia of patients with cystic fibrosis (CF) contribute to the dehydration of airway secretions which is responsible for secondary damage in the respiratory tract. The sodium-blocker amiloride inhibits sodium absorption depending on the dosage of the drug. This effect is documented by means of measuring transepithelial potential difference which is decreased following to inhalative amiloride administration in CF patients. Clinical long term efficiency has been shown to be probable, but has to be confirmed. Investigation in this field is difficult, because there are some other important factors which influence viscosity of mucus. The use of amiloride can best be evaluated, if it is given immediately after birth. However, the answer to some important questions has to be found before. 相似文献
5.
6.
Carsten Carstensen Kerstin Weinberg 《International journal for numerical methods in engineering》2003,56(15):2313-2330
Adaptive algorithms are important tools for efficient finite‐element mesh design. In this paper, an error controlled adaptive mesh‐refining algorithm is proposed for a non‐conforming low‐order finite‐element method for the Reissner–Mindlin plate model. The algorithm is controlled by a reliable and efficient residual‐based a posteriori error estimate, which is robust with respect to the plate's thickness. Numerical evidence for this and the efficiency of the new algorithm is provided in the sense that non‐optimal convergence rates are optimally improved in our numerical experiments. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
7.
Wan-Yu Wu Jyh-Ming Ting Hayo Zutz Dominika Lyzwa Inga Gerhards Carsten Ronning Hans Hofsäss 《Diamond and Related Materials》2008,17(7-10):1494-1497
While experimenting with the growth of metal-containing amorphous carbon (a-c:Me) thin films using two different growth processes, self-assembled multilayered structures were observed. One of the processes is a reactive magnetron sputter deposition process. The other process is a mass selective ion beam deposition process. Despite of the differences in the growth method and the growth condition, self-assembled multilayered thin films, consisting of alternating dark layer and bright layer, were obtained in both processes. Based on the consideration of energy for atomic diffusion in the thin films, the growth mechanism is discussed. 相似文献
8.
9.
Ioanna Roussaki Maria Strimpakou Carsten Pils 《Journal of Network and Systems Management》2007,15(1):57-74
The challenge of saturating all phases of pervasive service provision with context-aware functionality lies in coping with
the complexity of maintaining, retrieving and distributing context information. To efficiently represent and query context
information a sophisticated modelling scheme should exist. To distribute and synchronise context knowledge in various context
repositories across a multitude of administrative domains, streamlined mechanisms are needed. This paper elaborates on an
innovative context management framework that has been designed to cope with free-text and location based context retrieval
and efficient context consistency control. The proposed framework has been incorporated in a multi-functional pervasive services
platform, while most of the mechanisms it employs have been empirically evaluated. 相似文献
10.
Min Hu Lindemann T.. Gottsche T.. Kohnle J.. Zengerle R.. Koltay P.. 《Journal of microelectromechanical systems》2007,16(4):786-794
We demonstrate a discrete chemical release method, capable of delivering picoliter volumes of chemical solutions with 100 mum of spatial resolution and 20 mus of response time. The releasing mechanism is based on the transfer of pulsed liquid plugs through a hydrophobic air chamber. A microfluidic chip consisting of such a releasing array (2 times 10) is designed and fabricated. Numerical simulation and experimental testing are performed to verify the working principle. Advantages of this release-on-demand technology include leakage-free, fast response and versatile control of release profile. This new method could be a key enabling technology for precisely controlled release of biochemicals for modern pharmacological and biological research. 相似文献