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排序方式: 共有950条查询结果,搜索用时 15 毫秒
121.
声线法误差及其影响参数分析 总被引:1,自引:0,他引:1
给出了一种声场模拟计算的总体误差分析方法,基于该方法,通过实例探讨了声线类方法应用于复杂建筑模拟时的计算参数—声线总数、反射次数、散射系数等的取值范围,对声线类方法及相关软件的实际应用具有参考价值。 相似文献
122.
Airflow in a generic airplane cabin has been investigated numerically by means of Reynolds averaged Navier–Stokes computations and experimentally by particle image velocimetry (PIV). High and low Reynolds number as well as two layer turbulence models were tested for their ability to describe turbulent velocity fields. Special attention was given to the flow of the incoming air jet along the luggage compartment. Comparison with PIV measurements reveals that for reliable prediction of isothermal cabin flow, low Reynolds number turbulence models have to be used. 相似文献
123.
Eingegangen am 23. 08. 1996, in überarbeiteter Form am 26.03.1997 相似文献
124.
Anke Schbel-Ostertag Marina Braun-Unkhoff Claus Wahl Lambert Krebs 《Combustion and Flame》2005,140(4):359-370
The oxidation of benzene was studied as a function of residence time (τres=0–2.5 s), temperature (850–960 K), and oxygen concentration (O2=0.2–2.3%) in a heated laminar flow reactor at atmospheric pressure. Nitrogen, doped with 350 ppm benzene, was injected downstream of the burned gas from a near stoichiometric flame of methane + air. Gas samples were taken at different heights up the reactor and analyzed using GC-FID/TCD and HPLC techniques. Phenol and partially oxidized hydrocarbons such as acetaldehyde, formaldehyde, and acrolein were found with concentrations up to 50 ppm. At relatively low temperatures, the conversion of benzene was observed to proceed considerably more slowly at higher oxygen concentrations. Measured concentration profiles were modeled using detailed reaction schemes. A modified mechanism for the oxidation of benzene called BenWas was constructed from the mechanism of Zhang and McKinnon (Combust. Sci. Technol. 107 (1995) 261) by incorporating a submechanism for benzoquinone (OC6H4O) and by updating and enlarging the reaction scheme of cyclopentadiene (C5H6). The agreement between observed and predicted concentration profiles, e.g., of phenol (C6H5OH), acetylene (C2H2), and carbon monoxide (CO), was considerably improved by the use of the BenWas mechanism for rich and lean conditions, mainly due to the introduction of an additional pathway for phenyl oxidation (C6H5 + O2 = OC6H4O + H) and due to the changed kinetics of the oxidation of cyclopentadienyl (C5H5) in C5H5 + O2 = C5H4O + OH. The measured retardation of benzene oxidation with higher amounts of oxygen can be explained by the formation and reactions of peroxy radicals. 相似文献
125.
H. Claus 《Computing》1990,43(3):209-222
A continuous singly-implicit Runge-Kutta method is implemented for stiff retarded differential equations. The choice of this implicit Runge-Kutta method is based on stability investigations of wide classes of interpolationintegration schemes. The numerical results show the effectiveness of these methods for both stiff ordinary and retarded differential equations. 相似文献
126.
The problems of gossiping and broadcasting in one-way communication mode are considered for some prominent families of graphs. The complexity is measured as the number of communication rounds in the gossip and broadcast algorithms. The main result of the paper is the precise estimation of the gossip-problem complexity in cycles. To obtain this result a new combinatorial analysis of gossiping in cycles is developed. This analysis leads to an optimal lower bound on the number of rounds, and also to the design of an optimal algorithm for gossiping in cycles. The optimal algorithm for gossiping is later used to design new, effective algorithms for gossiping in important families of interconnection networks (cube connected cycles, butterfly networks). Furthermore, a new, effective algorithm for broadcasting in shuffle-exchange networks is developed.On leave from Comenius University, Bratislava, Czechoslovakia. 相似文献
127.
Jeppe Rass‐Hansen Hanne Falsig Betina Jørgensen Claus H Christensen 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2007,82(4):329-333
Increasing amounts of bioethanol are being produced from fermentation of biomass, mainly to counteract the continuing depletion of fossil resources and the consequential escalation of oil prices. Today, bioethanol is mainly utilized as a fuel or fuel additive in motor vehicles, but it could also be used as a versatile feedstock in the chemical industry. Currently the production of carbon‐containing commodity chemicals is dependent on fossil resources, and more than 95% of these chemicals are produced from non‐renewable carbon resources. The question is: what will be the optimal use of bioethanol in a longer perspective? Copyright © 2007 Society of Chemical Industry 相似文献
128.
CB Bratton D Casper A Ciocio R Claus M Crouch ST Dye S Errede W Gajewski M Goldhaber TJ Haines TW Jones D Kielczewska WR Kropp JG Learned JM LoSecco J Matthews R Miller M Mudan LR Price F Reines J Schultz S Seidel D Sinclair HW Sobel JL Stone L Sulak R Svoboda G Thornton van der Velde JC 《Canadian Metallurgical Quarterly》1988,37(12):3361-3363
129.
A set of fiber-optic sensing experiments that can be performed by senior undergraduates in a fiber optics laboratory is presented. The experiments are based on two stable phase-modulated sensors: a miniaturized Michelson-type fiber-optic interferometer that is relatively insensitive to temperature drifts; and a two-mode fiber used in a differential interferometric sensing scheme. Methods of construction are described, and several possible experiments are presented. These experiments introduce or strengthen the ideas of interference, elliptical-core fibers, and electromagnetic field propagation in fibers 相似文献
130.
Claus Breuer 《Fuel》1995,74(12):1767-1771