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排序方式: 共有573条查询结果,搜索用时 31 毫秒
61.
S. Licht O. Khaselev P. A. Ramakrishnan D. Faiman E. A. Katz A. Shames S. Goren 《Solar Energy Materials & Solar Cells》1998,51(1):9728
The photoelectrochemistry of single crystal C60 and fullerene photoelectrochemical solar cells is studied. Illuminated and immersed, C60 is shown to drive oxidation of several solution-phase redox couples. Utilization of a photoelectrochemical solid/liquid junction, rather than solid-state photovoltaic junction, improves the observed photocurrent. Utilization of a single crystal, rather than a polycrystalline film, of C60 decreases dark current to the extent that light-driven charge transfer dominates. The spectral response and current-voltage behaviour in several electrolytes is studied. A low-power fullerene photoelectrochemical solar cell, utilizing a regenerative polyiodide and ferri/ferrocyanide redox couple, is demonstrated. 相似文献
62.
P. J. Varman I. V. Ramakrishnan D. S. Fussell 《Circuits, Systems, and Signal Processing》1987,6(2):153-174
Parallel sorting algorithms have been proposed for VLSI implementation. Random defects in the silicon wafer and fabrication errors render processors in the wafer faulty, and may cause these algorithms to fail despite a significant number of nonfaulty processors. This paper presents twofault-tolerant pipelined sorting algorithms that would work on a wafer comprised of faulty and nonfaulty processors. Both the algorithms useO(n) processors and requireO(n) time to sortn elements.P. J. Varman's research was supported by an IBM Faculty Development Award, I. V. Ramakrishnan's by the ONR Grant N00014-84-K-0530 and NSF Grant ECS-84-04399, and D. S. Fussell's by NSF Grant MCS-8104017. 相似文献
63.
64.
An OSPF topology server: design and evaluation 总被引:10,自引:0,他引:10
Shaikh A. Goyal M. Greenberg A. Rajan R. Ramakrishnan K.K. 《Selected Areas in Communications, IEEE Journal on》2002,20(4):746-755
In large scale, operational Internet protocol networks, creating timely, accurate and network-wide views of the intradomain topology is a fundamental problem. Topical network backbones consist of hundreds of routers, which establish routing adjacencies with one another through static configuration and dynamic routing protocols, such as open shortest path first (OSPF). We describe the design of an OSPF topology server which tracks intradomain topology, by passively and safely listening into OSPFs reliable flooding mechanism, or by pushing and pulling information from the routers via the simple network management protocol. We provide a detailed evaluation and comparison of the two approaches in terms of operational issues, reliability and timeliness of information 相似文献
65.
In deregulated power system scenario coupled with smart grid technology, for networked load frequency control (LFC), an open communication structure, owing to low cost and flexibility, is preferred over dedicated networks in the feedback control loop for transmitting/receiving the data between the geographically displaced power system and the control center. In such a control scheme, closing the feedback loop through an open communication channel, in turn, introduces two additive time-varying delays of dissimilar characteristics in the feedback path. These delays degrade the performance of the closed-loop system, and exert a destabilizing effect on the overall system. In this paper, using Lyapunov-Krasovskii functional approach, a less conservative stability criterion is presented to ascertain delay-dependent stability of such network-controlled LFC systems with two additive time-varying delays in the feedback path in the presence of uncertain load disturbance conditions. Unlike the existing results, which are derived by combining these two delays into one, the proposed result considers the two delays as separate entities thereby imparting more generalization into the stability analysis. The effect of unknown exogenous load disturbance is incorporated by mathematically modeling them as a bounded non-linear time-varying function of current and delayed state vectors. 相似文献
66.
S. Licht P. A. Ramakrishnan D. Faiman E. A. Katz A. Shames S. Goren 《Solar Energy Materials & Solar Cells》1998,56(1):821
It is demonstrated that higher temperature and C60 oxygen depletion increase the photocurrent of fullerene photoelectrochemical solar cells (PEC). Fullerene/iodide electrolyte PEC consisting of intrinsic single crystal C60 in either aqueous 3 M KI, 0.01 M I2, or 0.1 M tetrabutyl ammonium iodide, 0.3 M LiClO4 in acetonitrile solution, drive regenerative photoinduced iodide oxidation. The photocurrent is increased by an order of magnitude (to 6.4 μA/cm2 under 100 mW/cm2 illumination) by an increase of the aqueous cell temperature from 24°C to 82°C. A similar order of magnitude increase in photocurrent is accomplished by O2 depletion pretreatment (24 h at 400°C in Ar) of the C60 to improve conductivity. However, this latter treatment also irreversibly increases the cell dark current. The spectral action of single crystal C60 is also probed, through the generated photoelectrochemical current in iodide, ferricyanide and sulfuric electrolytes as a function of wavelength. Band edges are observed at 720 nm (1.7 eV) and 560 nm (2.2 eV), and a substantial peak photocurrent response occurs at 395 nm (3.1 eV) and decreases at shorter wavelengths. 相似文献
67.
Abrasive particles used in chemical mechanical planarization (CMP) of copper often agglomerate and cause scratches on the finished surface. Abrasive-free CMP offers a feasible solution to this problem, and our present work examines four dicarboxylic acids (oxalic, malonic, succinic and glutaric, with increasing carbon chain lengths) as possible complexing agents for such a chemically dominated CMP process. At pH 3.0-4.0, oxalic and malonic acids are most effective for abrasive-free Cu removal. The rates of Cu dissolution and polish (with or without abrasives) are correlated with pH dependent distributions of mono-anionic (for oxalic and malonic) and neutral (for succinic and glutaric) acid species. The surface morphologies of a Cu wafers obtained by abrasive-free CMP in these acids also are more defect free and flat compared to those obtained using abrasives. 相似文献
68.
Data envelopment analysis (DEA) is proposed in this paper to generate local weights of alternatives from pair-wise comparison judgment matrices used in the analytic hierarchy process (AHP). The underlying assumption behind the approach is explained, and some salient features are explored. It is proved that DEA correctly estimates the true weights when applied to a consistent matrix formed using a known set of weights. DEA is further proposed to aggregate the local weights of alternatives in terms of different criteria to compute final weights. It is proved further that the proposed approach, called DEAHP in this paper, does not suffer from rank reversal when an irrelevant alternative(s) is added or removed. 相似文献
69.
RR Vines G Ramakrishnan JB Rogers LA Lockhart BJ Mann WA Petri 《Canadian Metallurgical Quarterly》1998,9(8):2069-2079
Killing of human cells by the parasite Entamoeba histolytica requires adherence via an amebic cell surface lectin. Lectin activity in the parasite is regulated by inside-out signaling. The lectin cytoplasmic domain has sequence identity with a region of the beta2 integrin cytoplasmic tail implicated in regulation of integrin-mediated adhesion. Intracellular expression of a fusion protein containing the cytoplasmic domain of the lectin has a dominant negative effect on extracellular lectin-mediated cell adherence. Mutation of the integrin-like sequence abrogates the dominant negative effect. Amebae expressing the dominant negative mutant are less virulent in an animal model of amebiasis. These results suggest that inside-out signaling via the lectin cytoplasmic domain may control the extracellular adhesive activity of the amebic lectin and provide in vivo demonstration of the lectin's role in virulence. 相似文献
70.