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81.
Mikhael Balabane Thierry Cazenave Luis Vázquez 《Communications in Mathematical Physics》1990,133(1):53-74
We prove the existence of stationary states for nonlinear Dirac equations of the form (E) $$i\sum\limits_{\mu = 0}^3 {\gamma ^\mu \partial _\mu \psi - M\psi + F\left( {\bar \psi \psi } \right)\psi = 0,} $$ whereM>0 andF is a singular self-interaction. In particular, in the model case whereF(s)=?s ?α, for some 0<α<1, and for every ω>M, there exists a solution of (E) of the form ψ(t, x)=e iωt?(x), wherex 0=t andx=(x 1,x 2,x 3), such that ? has compact support. IF 0<α<1/3, then ? is of classC 1. If 1/3<α<1, then ? is continuously differentiable, except on some sphere {|x|=R}, where |??| is infinite. 相似文献
82.
The Radiative Transfer Equation is the nonlinear transport equation
相似文献
83.
JiŘí Kvapil Josef Kvapil Bohumil Perner Michal Košelja Helena Jelínková 《Czechoslovak Journal of Physics》1990,40(11):1283-1287
The methods of growing YAG:Nd crystals with a flat interface and YAP:Nd crystals with a sharp conical interface are described. The form of the interface was controlled by the He and H2O content in the reducing atmosphere composed mainly of Ar and H2 as well as by axial temperature gradient above the melt level. The crystals of 120–180 mm in length were machined to the high-quality slabs. 相似文献
84.
Generalized solutions are defined for stochastic evolution equations of the formdY
t
=A
*
Y
t
dt + dZ
t
on the nuclear triplel(R
d
) L2(R
d
) l(R
d
), whereA does not mapl(R
d
) into itself. One case which is treated in detail involvesA = –(–)
/2
,0 < < 2. This example arises as the Langevin equation for the fluctuation limit of a system of particles migrating according to a symmetric stable process and undergoing critical branching in a random medium.The research of D. A. Dawson was supported by the Natural Sciences and Engineering Research Council of Canada. L. G. Gorostiza's research was supported in part by CONACyT Grants PCEXCNA-040319 and 140102 G203-006, Mexico. 相似文献
85.
86.
H. Eduardo Roman 《Journal of statistical physics》1990,58(1-2):375-382
Extensive Monte Carlo simulations of theant-in-the-labyrinth problem on randomL* L* L simple cubic lattices are performed, forL up to 960 on a CRAY-YMP supercomputer. The exponentk for the rms displacementr witht inrt
k
is found to bek=0.190±0.003. As a second approach, large percolation clusters with chemical shells up to 300 are generated on a simple cubic lattice at criticality. The diffusion equation is then solved by using the exact enumeration technique. The corresponding critical exponentd
w
is found to be 1/d
w
=0.250±0.003.On leave from I. Institut für Theoretische für Physik, Universität Hamburg, D-2000 Hamburg, Federal Republic of Germany. 相似文献
87.
88.
Mariano Giaquinta Giuseppe Modica Jiří souček 《Archive for Rational Mechanics and Analysis》1989,106(2):97-159
Summary In this paper we introduce some new classes of functions, among these a class of weak diffeomorphisms. In these classes we prove by direct methods the existence of minimizers for several kinds of variational integrals. In particular, we prove the existence of one-to-one orientation-preserving maps that minimize suitable energies associated with hyperelastic materials. The minimizers are also proved to satisfy equilibrium equations. Finally radial deformations are discussed in connection with cavitation. 相似文献
89.
Roman Murawski 《Archive for Mathematical Logic》1988,27(1):21-33
We consider expansions of models of Peano arithmetic to models ofA
2
s
-¦
1
1
+
1
1
–AC which consist of families of sets definable by nonstandard formulas. 相似文献
90.
Mária Hvastijová Jiří Kohout Helmut Köhler 《Monatshefte für Chemie / Chemical Monthly》1992,123(6-7):493-500
Summary New dicyanamide complexes of the typeM[N(CN)2]2
L
2 (M=Cu or Ni;L=2-, 3-, 4-aminopyridine, 2-amino-5-nitropyridine) and Co[N(CN)2]2 (2-amino-5-nitropyridine)2 were prepared and studied by spectroscopic methods as well as by room-temperature magnetic moments. The results show that the Cu(II) complexes have elongated pseudooctahedral structures while the Ni(II) and Co(II) complexes are octahedral. In most cases the N(CN)2 groups are in bridging function and through their cyanide nitrogens, or-more rarely-amide and cyanide nitrogens connect the basic structure units into polymeric conglomerates. In the Cu(II) systems exchange coupling is seen from the eff value or ESR spectrum.
Professor Viktor Gutmann zum 70. Geburtstag gewidmet 相似文献 |