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921.
Neudorf E.G. Kiguel D.L. Hamoud G.A. Porretta B. Stephenson W.M. Sparks R.W. Logan D.M. Bhavaraju M.P. Billinton R. Garrison D.L. 《Power Systems, IEEE Transactions on》1995,10(3):1667-1675
There is an emerging recognition that utility investments and other decisions that affect electric service reliability should be explicitly evaluated on the basis of their cost and benefit implications. A cost-benefit approach that quantifies the reliability benefits of alternatives in terms of the reduction in costs resulting from unserved energy enables the evaluation of generation and transmission capacity additions on a consistent, economic basis. This approach has been applied to two utility case studies. In a case study for Pacific Gas and Electric Company, it was used to evaluate three options for maintaining reliability in a major load center-two involving local generation, and the third, a new 230 kV transmission connection. In a case study for Duke Power Company, the approach was used to evaluate alternative designs for proposed additions to a transmission station. This paper describes the methodology and presents the two utility studies 相似文献
922.
Schubert E.F. Hunt N.E.J. Malik R.J. Micovic M. Miller D.L. 《Lightwave Technology, Journal of》1996,14(7):1721-1729
Resonant-cavity light-emitting diodes (RCLED) are novel, high-efficiency light-emitting diodes which employ optical microcavities. These diodes have higher intensities and higher spectral purity as compared to conventional LEDs. Analytical formulas are derived for the enhancement of the spontaneous emission along the optical axis of the cavity. The design rules for high-efficiency operation of RCLEDs are established. The temperature dependence of the emission intensity is analyzed in the range 20-80° and it is described by an exponential dependence with a characteristic temperature of 112 K. The modulation characteristics of RCLEDs exhibit 3 dB frequencies of 580 MHz. Eye diagrams at transmission rates of 622 Mb/s are wide open indicating the suitability of RCLEDs for high-speed data transmission 相似文献
923.
Summary Radical dispersion polymerization of styrene in aqueous ethanol solutions was performed in the presence of a new reactive polyethylene oxide stabilizer with thiol end groups. This reactive stabilizer was compared to the more conventional poly (N-vinylpyrrolidone). Particles size distribution, molecular weights and kinetics were investigated. We demonstrate that the thiol ended dispersant displays a high stabilizing efficiency. Particles size, molecular weights and conversions are strongly influenced by the amount of stabilizer used. 相似文献
924.
Universal portfolios with side information 总被引:10,自引:0,他引:10
Cover T.M. Ordentlich E. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1996,42(2):348-363
We present a sequential investment algorithm, the μ-weighted universal portfolio with side information, which achieves, to first order in the exponent, the same wealth as the best side-information dependent investment strategy (the best state-constant rebalanced portfolio) determined in hindsight from observed market and side-information outcomes. This is an individual sequence result which shows the difference between the exponential growth wealth of the best state-constant rebalanced portfolio and the universal portfolio with side information is uniformly less than (d/(2n))log (n+1)+(k/n)log 2 for every stock market and side-information sequence and for all time n. Here d=k(m-1) is the number of degrees of freedom in the state-constant rebalanced portfolio with k states of side information and m stocks. The proof of this result establishes a close connection between universal investment and universal data compression 相似文献
925.
G. Meaden P. G. Partridge M. N. R. Ashfold E. D. Nicholson A. Wisbey 《Journal of Materials Science》1996,31(11):2801-2805
Continuous chemical vapour-deposited diamond-coated fibres with tungsten wire or SiC fibre cores are attractive for reinforcing metals and ceramics. The fibres have been embedded in Ti-6A1-4V alloy to produce a diamond fibre-reinforced composite. Both the fibres and the composite material are extremely difficult to cut without damage by conventional mechanical methods. The use of a Nd-YAG laser to cut these materials is described. 相似文献
926.
927.
Models for the elastic deformation of honeycombs 总被引:8,自引:0,他引:8
A theoretical model has been developed for predicting the elastic constants of honeycombs based on the deformation of the honeycomb cells by flexure, stretching and hinging. This is an extension of earlier work based on flexure alone. The model has been used to derive expressions for the tensile moduli, shear moduli and Poisson's ratios. Examples are given of structures with a negative Poisson's ratio. It is shown how the properties can be tailored by varying the relative magnitudes of the force constants for the different deformation mechanisms. Off-axis elastic constants are also calculated and it is shown how the moduli and Poisson's ratios vary with applied loading direction. Depending on the geometry of the honeycomb the properties may be isotropie (for regular hexagons) or extremely anisotropic. Again, the degree of anisotropy is also affected by the relative magnitude of the force constants for the three deformation mechanisms. 相似文献
928.
Strom R.E. Yellin D.M. 《IEEE transactions on pattern analysis and machine intelligence》1993,19(5):478-485
The authors present a practical extension to typestate checking, which is capable of proving programs free of uninitialized variable errors even when these programs contain conditionally initialized variables where the initialization of a variable depends upon the equality of one or more tag variables to a constant. The user need not predeclare the relationship between a conditionally initialized variable and its tags, and this relationship may change from one point in the program to another. The technique generalizes liveness analysis to conditional liveness analysis. Like typestate checking, this technique incorporates a dataflow analysis algorithm in which each point in a program is labeled with a lattice point describing statically tracked information, including the initialization of variables. The labeling is then used to check for programming errors such as referencing a variable which may be uninitialized 相似文献
929.
930.