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991.
We develope a formalism which allows to treat Weyl symmetry with torsion as the gauge theory of the conformal group. The results of the standard Einstein—Cartan theroy are generalized and applied to the Maxwell-Einstein case.To my wife 相似文献
992.
In this study we report the levels of 3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid, homovallinic acid, tryptophan, 5-hydroxyindole-3-acetic acid and serotonin in lumbar cerebrospinal fluid (CSF) from patients with multiple sclerosis, cerebrovascular disease and muscular tension headache the later, as healthy controls. The separation of these substances was performed on a reversed phase column by ion pair high performance liquid chromatography and detection was made by a glassy carbon electrode set at +900 mV vs Ag+/AgCl. The whole separation was achieved within 25 min. Concentrations of all substances (10-1000 pmole/L) were linearly proportional to areas obtained. The system is sensitive, stable and reproducible. The significance of CSF levels of these metabolites from patients groups compared with healthy controls are discussed. 相似文献
993.
We estimate the possible influence of spectral line profile (Lorentz profile, Van Vleck–Weisskopf profile, and profile obtained by solving kinetic equation) on the rotation part of the dielectric permittivity of water-vapor monomers. Spectral regions corresponding to long-wavelength (static) and high-frequency (optical) limiting cases as well as regions in close proximity to resonances of various intensities are considered. The studied effects are compared with the corresponding effects on water-vapor absorption coefficient, which are related to factors determining the line-shape structure. 相似文献
994.
S. M. Lenzi C. H. Dasso M. A. Nagarajan H. M. Sofia A. Vitturi 《Acta Physica Hungarica A》1997,6(1-4):95-98
The existence of a neutron skin in neutron-rich nuclei is discussed in connection with the excitation of isovector dipole and quadrupole giant modes via isoscalar nuclear probes. In the case of large neutron excess, important contributions are obtained from the nuclear excitation, which may even become predominant according to proper kinematical conditions. At variance with the usual situation encountered in inelastic processes, constructive interference can be found between nuclear and Coulomb contributions. 相似文献
995.
P A Veitch 《BT Technology Journal》1997,15(3):181-188
Network resilience is a crucial area of concern for telecommunications network operators who aim to provide high availability services supported by a broadband platform based on ATM technology. This paper describes the development of an ATM test bed network which incorporates resilience by executing distributed restoration in the event of failures. Since the work originated from collaborative research between BT Laboratories and Alcatel Telecom of Belgium, the paper highlights challenges faced in developing a restorable network, both by a network operator, and a switch manufacturer. 相似文献
996.
997.
Using the theory of linear operators, guided electromagnetic wave propagation in inhomogeneous (nonreciprocal) biisotropic planar structures is analyzed in terms of a 2×2 matrix differential operator. Based on the concept of adjoint waveguide, a new biorthogonality relation for the guided hybrid modes is derived. For the special case of reciprocal biisotropic media or chiral media, the linear-operator formalism leads to a self-adjoint problem. As an application example, a general analysis of the radiation modes of a grounded chiroslabguide is also presented 相似文献
998.
D'Agostino S. D'Inzeo G. Marietti P. Tudini L. Betti-Berutto A. 《Microwave Theory and Techniques》1992,40(7):1576-1581
The authors present a novel approach to the evaluation of the DC parameters of a semiempirical MESFET model: starting from the analytical expression of the drain current derived from a previously proposed physics-based model, they provide a method to calculate the empirical DC parameters of the so-called Raytheon model. The comparison between computed and measured DC characteristics is quite satisfactory on GaAs microwave FETs of 1 μm or more gate length. By adding to the results obtained in this work an adequate model of the stray capacitances, the circuit performance can be optimized using the technological characteristics of active devices 相似文献
999.
V. I. Khromov V. V. Kharlamov A. M. Chekmarev G. A. Andropova B. A. Mamet A. S. Plachinda 《Hyperfine Interactions》1991,67(1-4):565-567
The iron containing corrosion products from water heat-carrier and deposits of the second circuit of the nuclear power plant were investigated by means of absorption Mössbauer spectroscopy. The nonstoichiometric magnetite and paramagnetic (superparamagnetic) iron oxide particles were found to be the main corrosion products. The fraction of the magnetically ordered phase varied in the range 0–100% depending on the location in the second circuit. 相似文献
1000.
It is shown that using position-sensitive detectors in μSR experiments to determine the muon stopping site in a target permits
one to study correlation effects in μSR time histograms produced by the decay of muons stopping in the same domain, i.e. to
obtain time correlators of μSR histograms of decays from a small region. These correlators contain information on the spatial
correlation of magnetic fields in the sample under study. The proposed method (μSR2-technique) allows measuring correlation radii (r
c
) down to 10−5 cm in a bulk sample. Among interesting physical phenomena occuring overr
c≥3×10−6 cm are, for instance, long wavelength fluctuations of the order parameter near the phase transition point in ferromagnets
and antiferromagnets and magnetic field correlations in magnet domains and spin glasses. One may use this method also on heavy-current
accelerators producing pulsed muon beams to investigate the variation in time of spatial correlations in magnets, spin glasses
and superconductors. 相似文献