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71.
Wilfredo Hernndez Evgenia Spodine Andres Vega Rainer Richter Jan Griebel Reinhard Kirmse Uwe Schrder Lothar Beyer 《无机化学与普通化学杂志》2004,630(10):1381-1386
The N‐acyl thiourea complexes bis[N,N‐diethyl‐N′‐(p‐nitrobenzoyl)‐thioureato]copper(II) ( 1a,1b ) and bis(N,N‐diphenyl‐N′‐benzoylthioureato)copper(II) ( 2a,2b ) crystallize in each case in two modifications. X‐ray structural analysis shows that 1a and 1b are cis‐trans isomers. This is very unusual for N‐acyl thioureato complexes because with exception of one platinum(II) complex up to now only cis complexes have been found. In contrast X‐ray structural analysis of both forms 2a and 2b of the other complex shows no cis‐trans pair. Both modifications are cis complexes. In solution both isomers of the copper(II) complexes are observable by EPR spectroscopy. 相似文献
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73.
We calculate the Higgs mass and the top mass starting from the principle that there are two, essentially degenerate minima in the Higgs effective potential; the second is at about the Planck energy scale M P = 1.2 × 1019 GeV. Thus the parameter of the quartic self-coupling λ h vanishes, as does β λH at M P. The new element is the addition of a quantum interaction term which couples the square of the Higgs field to the square of a pseudoscalar field, in the domain of the energy scale between about 1014 GeV and M P. We modify β λH at one loop. The pseudoscalar field which is introduced may be the field which is responsible for a spontaneous breakdown of discrete symmetry — for CP noninvariance at an energy scale of (1015–1016) GeV. The result is then a closer value for m H ? 163 GeV for the top pole-mass M t ? 190 GeV; both values are now close to the electroweak scale parameter $\langle {\phi _H}\rangle /\sqrt 2 = 175{\text{ GeV}}$ . In terms of dimensionless running coupling parameters, which determine the masses near to the electroweak scale, we get $\sqrt {{\lambda _H}} \cong 0.06$ and $gt/\sqrt 2 \cong 0.72$ , values that are close to each other and close to unity. 相似文献
74.
In this article, we investigate the response of a thin superconducting shell to an arbitrary external magnetic field. We identify
the intensity of the applied field that forces the emergence of vortices in minimizers, the so-called first critical field
H
c1 in Ginzburg–Landau theory, for closed simply connected manifolds and arbitrary fields. In the case of a simply connected
surface of revolution and vertical and constant field, we further determine the exact number of vortices in the sample as
the intensity of the applied field is raised just above H
c1. Finally, we derive via Γ-convergence similar statements for three-dimensional domains of small thickness, where in this setting point vortices are
replaced by vortex lines. 相似文献
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76.
In reply to a problem of Jean Leray concerning application of the Nielsen theory to differential systems for obtaining multiplicity results, we present a nontrivial example of such an application. The emphasis is on the parameter space in order to ensure that no subdomain becomes subinvariant under the related Hammerstein solution operator. To achieve this goal, we develop a general method applicable also for ordinary differential equations with or without uniqueness as well as for upper-Carathéodory differential inclusions. We are not aware that any alternative approach can be employed, even in the single-valued case. 相似文献
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Summary This paper discusses the problems associated with the symbolic treatment of functional equations and presents a Mathematica
package for the solution of real functional equations of real variables. The package includes a minimal basic database which
contains a reduced set of functional equations with its four components: equation, domain, class and the corresponding solution.
The word minimal is used in the sense that any equation that is solvable by the system using non-searching methods is excluded
from the database. The package incorporates a searching algorithm which can solve functional equations independently of their
notation and their algebraic representation. Not only general solutions but particular and candidate solutions are dealt with.
This implies a careful analysis of domains and classes. The package includes some methods for solving functional equations,
which are used when the input functional equations are not found in the database. Some methods have been implemented internally
and some are in an external package. Finally, some examples illustrate the use of the package. 相似文献