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21.
H. L. Du S. R. Rose Z. D. Xiang P. K. Datta X. Y. Li 《Materialwissenschaft und Werkstofftechnik》2003,34(4):421-426
The oxidation/sulphidation behaviour of a Ti‐46.7Al‐1.9W‐0.5Si alloy with a TiAl3 diffusion coating was studied in an environment of H2/H2S/H2O at 850oC. The kinetic results demonstrate that the TiAl3 coating significantly increased the high temperature corrosion resistance of Ti‐46.7Al‐1.9W‐0.5Si. The SEM, EDX, XRD and TEM analysis reveals that the formation of an Al2O3 scale on the surface of the TiAl3‐coated sample was responsible for the enhancement of the corroison resistance. The Ti‐46.7Al‐1.9W‐0.5Si alloy was also modified by Nb ion implantation. The Nb ion implanted and as received sampels were subjected to cyclic oxidation in an open air at 800oC. The Nb ion implantation not only increased the oxidation resistance but also substantially improved the adhesion of scale to the substrate. 相似文献
22.
23.
Self-organized public-key management for mobile ad hoc networks 总被引:6,自引:0,他引:6
In contrast with conventional networks, mobile ad hoc networks usually do not provide online access to trusted authorities or to centralized servers, and they exhibit frequent partitioning due to link and node failures and to node mobility. For these reasons, traditional security solutions that require online trusted authorities or certificate repositories are not well-suited for securing ad hoc networks. We propose a fully self-organized public-key management system that allows users to generate their public-private key pairs, to issue certificates, and to perform authentication regardless of the network partitions and without any centralized services. Furthermore, our approach does not require any trusted authority, not even in the system initialization phase. 相似文献
24.
Myers Nicholas D.; Payment Craig A.; Feltz Deborah L. 《Canadian Metallurgical Quarterly》2004,8(3):182
This study examined reciprocal relationships between collective efficacy and team performance over a season of competition in women's intercollegiate ice hockey within weekends where the opponent was constant for 2 games. Collective efficacy beliefs within 12 teams were assessed prior to both games for at least 7 weekends. Team performance indexes produced an overall measure of performance for each game. The average influence of Saturday collective efficacy on Saturday performance was moderate and positive after controlling for Friday performance. The average influence of Friday performance on Saturday collective efficacy was small and positive after removing the influence of Friday collective efficacy from Friday performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
Stewart C. Kai Shen Dwarkadas S. Scott M.L. Jian Yin 《Distributed Systems Online, IEEE》2004,5(10):1-1
The growth of the Internet and of various intranets has spawned a wealth of online services, most of which are implemented on local-area clusters using remote invocation (for example, remote procedure call/remote method invocation) among manually placed application components. Component placement can be a significant challenge for large-scale services, particularly when application resource needs are workload dependent. Automatic component placement has the potential to maximize overall system throughput. The key idea is to construct (offline) a mapping between input workload and individual-component resource consumption. Such mappings, called component profiles, then support high-performance placement. Preliminary results on an online auction benchmark based on J2EE (Java 2 Platform, Enterprise Edition) suggest that profile-driven tools can identify placements that achieve near-optimal overall throughput. 相似文献
26.
This article, the first of three articles on the synthesis of rice processing plants, focuses on the development of simplified mathematical models necessary for use in optimizing rice processing plants. The second concentrates on the optimal synthesis of a rice plant and the third on the sensitivity of the optimization to uncertainty in model parameters. Existing models for rice processing unit operations are not suitable for flowsheet optimization and new models need to be developed to overcome numerical difficulties that occur in optimization applications, specifically in mixed integer nonlinear programming (MINLP) applications. Simplified models of the drying, cooling, and tempering units are developed. In addition head rice yield models, used as a quality indicator, energy consumption, and economic models were also developed. Naturally, the new models exhibit some mismatch with respect to the existing models from which they were developed. However, a sensitivity analysis, presented in Part III, has shown that the optimal flowsheet structure was not sensitive to a lack of fit between the simplified and complex models. The simplified models were found adequate to be appropriate for use at the synthesis stage. 相似文献
27.
The electrical properties and microstructure of (Ba,Y)TiO3 PTCR ceramics were studied. The results indicate that the Mn ions increase the intergranular barrier height and produce a high-resistance layer on the grain surface. The temperature-dependent resistances of the grain bulk, surface layer, and grain boundaries, the temperature coefficient of resistance, and the magnitude of the varistor effect were assessed as a function of Mn content. 相似文献
28.
Kilchytska V. Neve A. Vancaillie L. Levacq D. Adriaensen S. van Meer H. De Meyer K. Raynaud C. Dehan M. Raskin J.-P. Flandre D. 《Electron Devices, IEEE Transactions on》2003,50(3):577-588
This work presents a systematic comparative study of the influence of various process options on the analog and RF properties of fully depleted (FD) silicon-on-insulator (SOI), partially depleted (PD) SOI, and bulk MOSFET's with gate lengths down to 0.08 /spl mu/m. We introduce the transconductance-over-drain current ratio and Early voltage as key figures of merits for the analog MOS performance and the gain and the transition and maximum frequencies for RF performances and link them to device engineering. Specifically, we investigate the effects of HALO implantation in FD, PD, and bulk devices, of film thickness in FD, of substrate doping in SOI, and of nonstandard channel engineering (i.e., asymmetric Graded-channel MOSFETs and gate-body contacted DTMOS). 相似文献
29.
T. Choi J.‐H. Jang C.K. Ullal M.C. LeMieux V.V. Tsukruk E.L. Thomas 《Advanced functional materials》2006,16(10)
The probing of the micromechanical properties within a two‐dimensional polymer structure with sixfold symmetry fabricated via interference lithography reveals a nonuniform spatial distribution in the elastic modulus “imprinted” with an interference pattern in work reported by Tsukruk, Thomas, and co‐workers on p. 1324. The image prepared by M. Lemieux and T. Gorishnyy shows how the interference pattern is formed by three laser beams and is transferred to the solid polymer structure. The elastic and plastic properties within a two‐dimensional polymer (SU8) structure with sixfold symmetry fabricated via interference lithography are presented. There is a nonuniform spatial distribution in the elastic modulus, with a higher elastic modulus obtained for nodes (brightest regions in the laser interference pattern) and a lower elastic modulus for beams (darkest regions in the laser interference pattern) of the photopatterned films. We suggest that such a nonuniformity and unusual plastic behavior are related to the variable material properties “imprinted” by the interference pattern. 相似文献
30.
An Imhoff tank was reconstructed into a 250 m3 UASB reactor in order to treat a malting plant wastewater. The UASB was inoculated with sludge from an anaerobic lagoon used for slaughterhouse wastewater treatment. After two months of operation the reactor achieved full load with an HRT of 17 h, a COD removal higher than 80% and a biogas production of 300 m3/day (77% average methane content), with an organic loading rate of 3.6 kgCOD/m3.d (0.24 kgCOD/kgVSS.d). A yield coefficient of 0.09 gVSS/gCODrem was found from a mass balance. The fat present in the inoculated sludge (48 mg/gSSV) did not affect the start up performance. Sludge from the inoculum with high content of fat (270 mg/gSSV), was separated by flotation in the first week of operation. The COD removal efficiency was scarcely influenced by the reactor operation temperature (17-25 degrees C). 相似文献