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排序方式: 共有199条查询结果,搜索用时 46 毫秒
41.
Numerical investigation of turbulent free jet flows issuing from rectangular nozzles: the influence of small aspect ratio 总被引:1,自引:0,他引:1
Ehsan Faghani Reza Maddahian Pedram Faghani Bijan Farhanieh 《Archive of Applied Mechanics (Ingenieur Archiv)》2010,80(7):727-745
In this research, the fluid and thermal characteristics of a rectangular turbulent jet flow is studied numerically. The results
of three-dimensional jet issued from a rectangular nozzle are presented. A numerical method employing control volume approach
with collocated grid arrangement was employed. Velocity and pressure fields are coupled with SIMPLEC algorithm. The turbulent
stresses are approximated using k–e{\varepsilon} model with two different inlet conditions. The velocity and temperature fields are presented and the rates of their decay
at the jet centerline are noted. The velocity vectors of the main flow and the secondary flow are illustrated. Also, effect
of aspect ratio on mixing in rectangular cross-section jets is considered. The aspect ratios that were considered for this
work were 1:1 to 1:4. The results showed that the jet entrains more with smaller AR. Special attention has been drawn to the
influence of the Reynolds number (based on hydraulic diameter) as well as the inflow conditions on the evolution of the rectangular
jet. An influence on the jet evolution is found for smaller Re, but the jet is close to a converged state for higher Reynolds numbers. The inflow conditions have considerable influence
on the jet characteristics. 相似文献
42.
43.
AbstractWe introduce diffeological algebraic hyperstructures such as diffeological hypergroups and diffeological polygroups, which are generalizations of diffeological groups. After providing some examples of these notions, we investigate the relationships between diffeological hypergroups and diffeological groups. It is proved that there is an equivalence of categories between subductions over diffeological groups and diffeological complete hypergroups. We finally show how every diffeological polygroup is a subpolygroup of a diffeological poly-monoid of hyper-diffeomorphisms.Communicated by J. L. Gomez Pardo 相似文献
44.
Moradi Bijan Ghasemi Shahab Hosseini Moghadam Amir Rasaei Mohammad Reza Sajjadi Mozhdeh 《Meccanica》2021,56(12):2961-2977
Meccanica - A Free Energy Lattice Boltzmann Method has been developed to characterize dominant forces and regimes involved in the capillary rise imbibition process. The comparison of the capillary... 相似文献
45.
Anuradha Lahiri Prodyot Kumar Roy Bijan Bagchi 《International Journal of Theoretical Physics》1989,28(2):183-189
Using the ladder operator technique, a construction of the supersymmetric Hamiltonian is proposed. We show that the accidental degeneracies associated with the Coulomb and isotropic oscillator problems may be attributed to the existence of a supersymmetry of the Hamiltonians. 相似文献
46.
Jing Li Wanming Sun Bijan Pashaie Dhali S.K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1995,23(4):672-678
Streamer discharges are formed in a dielectric-barrier discharge used for nonthermal plasma generation. The results of simulation of streamer type discharge in a flue gas mixture is reported. A Monte Carlo simulation is done to obtain the transport and appropriate rate coefficients. The transport and rate coefficients calculated from the Monte Carlo is used to solve the conservation equations for electron, positive and negative ions, together with the Poisson's equation. The G-factor (radicals produced per 100 eV of electrical energy input to the discharge) obtained for Townsend-type discharge is higher as compared to a streamer-type discharge. Also experimental results of the SO2 removal efficiency is compared to theoretical predictions 相似文献
47.
Bijan Etemadi Abdol Abadi Rex A. Palmer Brian W. Fitzsimmons 《Journal of chemical crystallography》1988,18(1):35-53
The crystal structure of bis (NN-di(n-propyl)dithiocarbamato iron(III) iodide, FeIII(S2CN6H14)2I, has been determined by the heavy-atom method and refined toR=0.055 for 3487 reflections withI(hkl)>3I(hkl). The crystals are triclinic,C¯1,Z=8,a=27.644(6),b=19.186(4),c=8.694(2) Å,=87.79(1),=88.72(1), =101.87(2)°. The I-Fe bond lengths are different in the two moleculesA andB in the asymmetric unit, having values of 2.642 Å (2.655) and 2.612 Å (2.634) respectively (libration-corrected values given in parentheses). The measured effective magnetic moment
eff3.89 BM, independent of temperature (93-353K), suggests a spinS of 3/2 with three unpaired electrons for FeIII. 相似文献
48.
Synthesis,Structure, Bonding,and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2}2{μ‐η2:η2‐B2H4}] and [{Cp*M(CO)2}2B2H2M(CO)4], M=Mo,W
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Dr. Bijan Mondal Ranjit Bag Sagar Ghorai Dr. K. Bakthavachalam Prof. Eluvathingal D. Jemmis Prof. Sundargopal Ghosh 《Angewandte Chemie (International ed. in English)》2018,57(27):8079-8083
The reaction of [(Cp*Mo)2(μ‐Cl)2B2H6] ( 1 ) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO)2}2{μ‐η2:η2‐B2H4}] ( 2 ). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged Cs structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum–alkyne complex [{CpMo(CO)2}2C2H2]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO)4] fragment, [{Cp*Mo(CO)2}2 B2H2W(CO)4] ( 3 ) was isolated upon treatment with [W(CO)5?thf]. Compound 3 shows the intriguing presence of [B2H2] with a short B?B length of 1.624(4) Å. We isolated the tungsten analogues of 3 , [{Cp*W(CO)2}2B2H2W(CO)4] ( 4 ) and [{Cp*W(CO)2}2B2H2Mo(CO)4] ( 5 ), which provided direct proof of the existence of the tungsten analogue of 2 . 相似文献
49.
Precise measurements of the electrical conductances of solutions of potassium thiocyanate (KCNS), ammonium thiocyanate (NH4CNS), sodium nitrate (NaNO3) and ammonium nitrate (NH4NO3) in 2-ethoxyethanol (EE) at temperatures 35, 40, 45 and 50,∘C are reported. The conductance data have been analyzed by the 1978 Fuoss conductance equation. A thermodynamic analysis of the ionic association processes has also been made and the Coulombic forces are found to play a major role in the association processes. The ionic contributions to the limiting equivalent conductances have been determined using the reference electrolyte method. Strong association was found for all these electrolytes in this solvent medium. The cations are found to be substantially solvated in 2-ethoxyethanol, whereas the anions appear to have only weak interaction with the solvent molecules. 相似文献
50.
John Koenitzer Bijan Khazai Jacob Hormadaly Robert Kershaw Kirby Dwight Aaron Wold 《Journal of solid state chemistry》1980,32(1):128-129
The orthorhombic α-PbO2 phase of FeNbO4 was prepared and its photoelectronic properties measured: Sintered disks were shown to be n type and gave a resistivity of 40 Ω-cm. Measurements of the photoresponse gave a flat-band potential between 0.1 and 0.4 V vs SCE at a pH of 8.5 and an optical band gap of 2.08(2) eV. Several higher-energy band gaps at 2.68(2), 2.94(2), 3.24(2), and 4.38(2) eV were also determined. There appears to be an enhancement of the quantum efficiency due to the presence of [FeO6] active centers while retaining the fundamental characteristics of the [NbO6] octahedra. 相似文献