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41.
Jacek Pozorski Sergei Sazhin Marta Wacławczyk Cyril Crua David Kennaird Morgan Heikal 《Flow, Turbulence and Combustion》2002,68(2):153-165
Analytical expressions for mass concentration of liquid fuel in a spray are derived taking into account the effects of gas
turbulence, and assuming that the influence of droplets on gas is small (intitial stage of spray development). Beyond a certain
distance the spray is expected to be fully dispersed. This distance is identified with the maximum spray penetration. Then
the influence of turbulence on the spray stopping distance is discussed and the rms spray penetration is computed from a trajectory
(Lagrangian) approach. Finally, the problem of spray penetration is investigated in a homogeneous two-phase flow regime taking
into account the dispersion of spray away from its axis. It is predicted that for realistic values of spray parameters the
spray penetration at large distances from the nozzle is expected to be proportional to t
2/3 (in the case when this dispersion is not taken into account this distance is proportional to t
1/2). The t
2/3 law is supported by experimental observations for a high pressure injector.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
42.
Polarization effects on population transfer by stimulated Raman transition using overlapping time dependent pump and Stokes
laser pulses from the ground X
1Σ
g
/+
(v
g=0, J
g=1) level of H2 to the final X
1Σ
g
/+
(v
f=1, J
f=1) level via the intermediate B
1Σ
u
/+
(v
i=14, J
i=0,2), C
1Π
u
/+
(v
i=3, J
i=2) and C
1Π
u
/−
(v
i=3, J
i=1) levels have been theoretically investigated by applying the density matrix formalism. We have studied in detail the dependence
of the population transfer on time delay between two pulses for the cases of on-resonance excitations considering linear parallel
and same-sense circular polarizations of the fields. The pump and Stokes fields are taken as having Gaussian pulse shapes
with peak intensities I
P
/0
(I
S
/0
)=2 × 106 and 1 × 107 W/cm2. Density matrix equations have been solved for each value of the magnetic quantum number M
g(0, ±1) of the initial ground level taking into account the M
g dependence of the Rabi frequencies. M
g — averaged population transfer to the final level has also been calculated. For resonance excitations to the B(14, 0) or C(3, 1) levels, appreciable population transfer is achieved for intuitive pulse order for some particular values of M
g and M
i (magnetic quantum number of the resonant intermediate level) depending on the nature of polarizations. The calculated values
of M
g — averaged population transfer for the two cases of polarizations show that for on-resonance excitation to the B(14, 0) or the C(3, 1) level, linear parallel polarization of the laser fields yield more transfer efficiency whereas for resonance excitation
to the B(14, 2) level, larger population transfer results from the same-sense circular polarizations. For resonance excitation to
the C(3, 2) level, M
g — averaged population is found to be almost polarization independent. The calculations for the six-level H2 system reveal some interesting features of polarization effects on the population transfer efficiency. 相似文献
43.
In this paper, we establish several inequalities for some differantiable mappings that are connected with the Riemann-Liouville fractional integrals. The analysis used in the proofs is fairly elementar... 相似文献
44.
S.L. Mitchell M. VynnyckyI.G. Gusev S.S. Sazhin 《Applied mathematics and computation》2011,217(22):9219-9233
A recently derived numerical algorithm for one-dimensional time-dependent Stefan problems is extended for the purposes of solving a moving boundary problem for the transient heating of an evaporating spherical droplet. The Keller box finite-difference scheme is used, in tandem with the so-called boundary immobilization method. An important component of the work is the careful use of variable transformations that must be built into the numerical algorithm in order to preserve second-order accuracy in both time and space - an issue not previously discussed in relation to this widely-used scheme. In addition, we demonstrate that our solution is in close agreement with the solution obtained using an alternative numerical scheme that employs an analytic solution of the heat conduction equation inside the droplet, for which the droplet radius was assumed to be a piecewise linear function of time. The advantages of the new method are discussed. 相似文献
45.
In this paper the singularly perturbed initial boundary value problems for the nonlocal reaction diffusion system are considered. Unsing the iteration method and the comparison theorem, the existence, uniqueness and its asymptotic behavior of solution for the problem are studied. 相似文献
46.
M. V. Sazhin S. D. Ustyugov V. M. Chechetkin 《Journal of Experimental and Theoretical Physics》1998,86(4):629-635
This paper discusses the gravitational radiation that accompanies the formation of a rotating protoneutron star. Mainly large-scale
entropy inhomogeneities develope inside the star. As a result, bubbles of hot nuclear substance are formed, and convective
motions arise: bubbles of hot neutron matter float to the surface of the star, while cold matter sinks to its center. Such
large-scale motions of material give rise to an inhomogeneous mass distribution inside the star. Variable asymmetry appears
in the mass distribution, and this causes gravitational radiation.
Zh. éksp. Teor. Fiz. 113, 1153–1166 (April 1998) 相似文献
47.
V. V. Randoshkin V. A. Polezhaev Yu. N. Sazhin R. R. Sysoev 《Physics of the Solid State》2003,45(7):1272-1279
Using high-speed photography, dynamic magnetic structures are studied in Bi-containing (210)-oriented single-crystal films of (Bi,Y,Lu,Pr)3(Fe,Ga)5O12 grown through liquid-phase epitaxy from an overcooled solution in the melt on (Gd,Ga)3(Mg,Zr,Ga)5O12 substrates. At various temperatures, the ranges of pulsed magnetic fields are determined in which unidirectional anisotropy of domain wall velocity and spatial distortions of moving domain walls are observed. 相似文献
48.
Microlensing of background stars by neutralino stars, which were proposed in a recent work by Gurevich and Zybin as the component
making the main contribution to the dark matter, is studied. The optics of such a gravitational microlens—the equation of
the lens, the solution of this equation, the intensification of images, and the critical and caustic curves—are analyzed in
detail in a quite simple approximation. A set of different values of the parameters of the problem is studied.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 12, 894–899 (25 June 1996) 相似文献
49.
We have investigated the superconducting properties of the Bi1.7 Pb0.3Sr2Ca2−xCe
x
Cu3O10+δ system with x=0.00, 0.02, 0.04, 0.08 and 0.1 by X-ray diffraction and magnetic susceptibility. The substitution of Ce for Ca has been found
to drastically change the superconducting properties of the system. X-ray diffraction studies on these compounds indicate
decrease in the c-parameter with increased substitution of Ce at Ca site and volume fraction of high T
c (2 : 2 : 2 : 3) phase decreases and low T
c phase increases. The magnetic susceptibility of this compound shows that the diamagnetic on set superconducting transition
temperature (onset) varies from 109 K to 51 K for x=0.00, 0.02, 0.04, 0.08 and 0.1. These results suggest the possible existence of Ce in a tetravalent state rather than a trivalent
state in this system; that is, Ca2+ → Ce4+ replacement changes the hole carrier concentration. Hole filling is the cause of lowering T
c of the system. 相似文献
50.