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排序方式: 共有1670条查询结果,搜索用时 15 毫秒
961.
Vedanth Nair Matthew Sirignano Benjamin Emerson Ben Halls Naibo Jiang Josef Felver Sukesh Roy Jim Gord Tim Lieuwen 《Proceedings of the Combustion Institute》2019,37(2):1489-1496
This paper analyzes the time averaged flow structure of a reacting jet in cross flow (RJICF), emphasizing the structure of the counter-rotating vortex pair (CVP) by using simultaneous tomographic particle image velocimetry (TPIV) and hydroxyl radical planar laser induced fluorescence (OH-PLIF). It was performed to determine the extent to which heat release, and the associated effects of gas expansion and baroclinic vorticity production, impact the structure of the CVP. These results show the clear presence of a CVP in the time averaged flow field, whose trajectory lies below the jet centerline on either side of the centerplane. Consistent with other measurements of high momentum flux ratio JICF in nonreacting flows, there is significant asymmetry in strength of the two vortex cores. The strength and structure of the CVP was quantified with vorticity and swirling strength (λci), showing that some regions of the flow with high shear are not necessarily accompanied by large scale bulk flow rotation and vice-versa. The OH PLIF measurement allows for correlation of the flame position with the dominant vortical structures, showing that the leeward flame branch lies slightly above, as well as, in the region between the CVP cores. 相似文献
962.
Lena Scherthan Sebastian F. M. Schmidt Hendrik Auerbach Tim Hochdrffer Juliusz A. Wolny Wenli Bi Jiyong Zhao Michael Y. Hu Tom Toellner E. Ercan Alp Dennis E. Brown Christopher E. Anson Annie K. Powell Volker Schünemann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3690-3690
963.
Worldwide, landfills are the most common way to dispose of waste, but have an impact on the environment as a result of harmful gas and leachate production. Estimating the long-term behaviour of a landfill in regard to this gas production and organic degrading, as well as to settlement and waste water production, is of high importance. Therefore, a model has been developed to simulate these processes. This constitutive model is based on the multiphase Theory of Porous Media. The body under investigation consists of an organic and an inorganic phase as well as a liquid and a gas phase. The equations of the model are developed on the basis of a consistent thermo-mechanical approach including the momentum balance for the solid phase and the mixture, the energy balance for the mixture and the mass balance for the gas phase. All interactions between the constituents such as mass transfers, interaction forces and energy fluxes are taken into consideration. The strongly coupled set of partial differential equations is implemented in the finite element code FEAP. The theoretical framework and the results of meantime successfully performed simulation of a real landfill body will be shown. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
964.
F. Willaert K. Kyllönen H. Sarkkinen H. Mäder 《Journal of Molecular Spectroscopy》2008,248(2):146-152
The pure rotational spectra of CH2DI and CHD2I have been measured by microwave Fourier transform spectroscopy, millimeterwave spectroscopy and submillimeterwave spectroscopy. The quadrupole hyperfine structure due to iodine has been analyzed by direct diagonalization of the quadrupole tensor. For the J = 1-0 transition of the ground state of CH2DI, the quadrupole hyperfine structure due to deuterium could be resolved and the quadrupole coupling constant eQqaa(D) determined.Accurate rotational and centrifugal distortion constants (up to sextic terms) have been determined. They are compared to the constants derived from the ground state combination differences (GSCD). A good agreement is observed but it is also found that the two kinds of data (GSCD and microwave) are complementary and a combined fit allows us to significantly improve the accuracy of the constants. 相似文献
965.
Microvascular oxygen quantification using two-photon microscopy 总被引:1,自引:0,他引:1
An instrument is demonstrated that is capable of three-dimensional (3D) vasculature imaging and pO(2) quantification with high spatial resolution. The instrument combines two-photon (2P) microscopy with phosphorescence quenching to measure pO(2). The instrument was demonstrated by performing depth-resolved microvascular pO(2) measurements of rat cortical vessels down to 120 microm below the surface. 2P excitation of porphyrin was confirmed, and measured pO(2) values were consistent with previously published data for normoxic and hyperoxic conditions. The ability to perform 3D pO(2) measurements using optical techniques will allow researchers to overcome existing limitations imposed by polarographic electrodes, magnetic resonance techniques, and surface-only pO(2) measurement techniques. 相似文献
966.
Tim Smithin 《The Journal of the Operational Research Society》1991,42(11):1033-1033
967.
Matthew R. Brown Christine M. O'Keefe Tim Penttila 《Designs, Codes and Cryptography》1999,18(1-3):63-70
We show that if an ovoid of Q (4,q),q even, admits a flock of conics then that flock must be linear. It follows that an ovoid of PG (3,q),q even, which admits a flock of conics must be an elliptic quadric. This latter result is used to give a characterisation of the classical example Q -(5,q) among the generalized quadrangles T 3(
), where
is an ovoid of PG (3q) and q is even, in terms of the geometric configuration of the centres of certain triads. 相似文献
968.
It is a theorem of Shor that ifG is a word-hyperbolic group, then up to isomrphism, only finitely many groups appear as fixed subgroups of automorphisms ofG. We give an example of a groupG acting freely and cocompactly on a CAT(0) square complex such that infinitely many non-isomorphic groups appear as fixed
subgroups of automorphisms ofG. Consequently, Shor’s finiteness result does not hold if the negative curvature condition is relaxed to either biautomaticity
or nonpositive curvature.
D. T. Wise was supported by grants from FCAR and NSERC. 相似文献
969.
Let Γ denote a noncommutative free group and let Ω stand for its boundary. We construct a large class of unitary representations
of Γ. This class contains many previously studied representations, and is closed under several natural operations. Each of
the constructed representations is in fact a representation of Γ ⋉λ
C(Ω). We prove here that each of them is irreducible as a representation of Γ ⋉λ
C(Ω). Actually, as will be shown in further work, each of them is irreducible as a representation of Γ, or is the direct sum
of exactly two irreducible, inequivalent Γ-representations.
This research was supported by the Italian CNR. 相似文献
970.
Steve?M.?GerstenEmail author Derek?F.?Holt Tim?R.?Riley 《Geometric And Functional Analysis》2003,13(4):795-814
We prove that every finitely generated nilpotent group of class c admits
a polynomial isoperimetric function of degree c + 1 and a linear
upper bound on its filling length function. 相似文献