The relation between the relativistic 5D Wesson theory and the Newtonian variable mass theory

The existence of Newtonian analogs to spatially homogeneous and isotropic cosmological models of the relativistic 5D Wesson variable mass theory is investigated. By treating the continuous universe matter creation process by the methods of standard hydrodynamics, it is shown that classical analogs are obtained only if the cosmological constant is null and the spatial curvature is positive.     

Cosmological Relativity: Determining the Universe by the Cosmological Redshift as Infinite and Curved

Using cosmological relativity theory, we derive the formula for the cosmological redshift written explicitly in terms of 1 – , where = /_c is the ratio of the average mass density to the critical closure density. Based on the present day data of observed redshifts, we conclude that < 1, which means the universe is infinite and curved, and expands forever.     

Single crystal diffraction patterns of germanium. Part II

The rocking curves of Ge (111), (220), (333) for CuK ₁ radiation were measured by means of the triple-crystal diffractometer. Perfect silicon single crystals, cut parallel to the (111) plane were used in the monochromator part of the triple-crystal diffractometer. The results prove the suitability of such a monochromator for studying diffraction patterns.

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. II

(rocking curves) (111), (220), (333) CuK ₁ . , (111). .

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In conclusion the authors thank A. Haruý for preparing the germanium single crystals and they are indebted to V. Smutná and A. Irra for the care with which they carried out various tasks.     

The Gelfand-Levitan equation and its application to the scattering of neutrons on protons

The Gelfand-Levitan equation for the kernelP(r, r) (withrr) is formulated and then applied for determining the scattering potential in the scattering of slow neutrons on protons (for the case when the dependence of the nuclear forces on the spins can be neglected and onlys-scattering need be considered). The potentials obtained are the same as the Bargmann ones, found by a different method.

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- P(r, r) ( rr). , ( s- ). , .

     

An exact bianchi type-V tilted cosmological model with matter and an electromagnetic field

We present a cosmological solution of the source-free Einstein-Maxwell equations with stiff matter and an electromagnetic null field, which is a locally rotationally symmetric tilted Bianchi type-V universe.     

The energy of periodic surface structures in ferromagnetism

The periodic domain structures on unfavourably oriented surface layers of ferromagnetic materials were studied both experimentally and theoretically. The connection between the surface structure and the crystallographic orientation of the crystals was confirmed. All the terms contributing to the total energy of the surface layer were calculated. A general solution of the potential problem is given for arbitrary periodic distribution of the charges.

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A critical density cosmological model with varying gravitational and cosmological “constants”

A cosmological model in which the universe has its critical density and the gravitational and cosmological constantsG and are time-dependent is presented. The model may possibly solve the horizon and monopole problems. It predicts a perpetually expanding universe in whichG increases and decreases with time in a manner consistent with conservation of the energy-momentum tensor. The model also allows the calculation of various cosmological parameters.     

ИЗМЕНЕНИЯ ТОНКОЙ СТР УКТУРЫ МОЛОТОГО КОБА ЛТА

- , . , , - . - , , , - .     

The electroluminescence of ZnS-Cu,Mn

The brightness waves of ZnS-Cu, Mn phosphor were investigated and it was found that their shape changes from that characteristic for copper-activated phosphors to that characteristic for manganese-activated phosphors as a function of the magnitude of the voltage applied, the length of the pulses and the temperature. In order to explain the results it is assumed that simultaneously with the mechanism of electroluminescence, accepted for ZnS-Cu (ionization of activators; recombination and radiation delayed in phase compared with voltage), there exists an immediate recombination of the Cu activators in the barriers, which is accompanied by radiation in phase with the voltage.

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ZnS-Cu, Mn

ZnS-Cu, Mn. , , , , , , , , . , , ZnS-Cu ( ; , ), : Cu , , .

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In conclusion, the authors thank Dr. M. Trlifaj for valuable discussions and M. Skala for supplying the electroluminescent phosphor of ZnS-Cu, Mn.     

Absorption Spectra of Excited Ruby Crystals

We have investigated the absorption spectra of excited laser single crystals of ruby. The longlived increase in absorption depending on the degree of excitation is observed in optically excited crystals of ruby in a wide spectral range. Moreover, in the absorption spectrum of a postexcited ruby we discovered the excitationinduced longlived kinetic instability, namely, the noiselike quasiline component variable in time and over the spectrum and imposed on the smooth spectral curve.     

Nonvacuum taub-type cosmological model

The Einstein universe is a simple model describing a static cosmological spacetime, having a constant radius and a constant curvature, and, as is well known, it does not describe our universe. We propose a model which is an extension of Einstein's. Our metric, havingR × S ³ topology, describes a nonisotropic homogeneous closed (finite) universe of Bianchi type IX. This metric is similar to that of Taub, but is simpler. Unlike the Taub solution (which is a cosmological extension of the NUT solution), however, the universe described by our metric contains matter. Like the Taub metric, our metric has two positive constants (, T). The gravitational red shift calculated from our metric is given. Similarly to the Schwarzschild metric, which has a singularity atr = 2m, this metric has the same kind of singularity att = 2. The maximal extension of the coordinates in our metric is fairly analogous to that of the Schwarzschild metric.     

Влияние давления на а бсорбцию галогенидо в серебра. Часть II

AgBr, Agcl AgI — 160°C. AgBr AgCl . AgI .     

The causal universe

Creation of matter is possible in the cosmological context, without cost of energy. This creation is regulated by the laws of quantum mechanics and general relativity. These elements are used to conceive a singularity-free causal open homogeneous isotropic cosmology. The history of the universe unfolds in two stages: the fireball production stage, which occurs as the response to a spontaneous local disturbance, is followed by free expansion. The latter extrapolates back to the former to avoid the initial big-bang singularity.This essay was awarded the first prize for 1978 by the Gravity Research Foundation. (Ed.)     

Causal Viscous Cosmological Models With Variable G and Λ

Einstein's equations with variable gravitational and cosmological constants are considered in the presence of a bulk viscous fluid source described by the truncated causal theory of Israel–Stewart, for the spatially flat homogeneous and isotropic universe. A solution is found in which the cosmological term varies inversely with the square of time. However, the gravitational constant G is found to be increasing with time.     

Energy-nonconserving Planck fluctuations and strong forces

On the basis of the recent demonstration that sources of the dual Riemann tensor are violations of local energy-momentum conservation, it is hypothesized that matter is subject to the Heisenberg uncertainty principle because of stochastic Planck-scale fluctuations in the Euclidean geometry of the vacuum. The identification of such singularities with unitons, whose masses are quantized in discrete units of the Planck mass, and also with the sources of strong gravity, is shown to lead to the correct strength, range, and duration of strong interactions. A vacuum-induced cosmological term, due to coupling of spin to space-time torsion, results in massive gravitons, with mass similar to the spin-2 mesons, and a Yukawa, rather than Newtonian, variation of the hadron gravitational potential, thus adding support to strong gravity theories of the strong force.     

Isotropic singularities and isotropization in a class of Bianchi type-VI h cosmologies

The evolution of a class of exact spatially homogeneous cosmological models of Bianchi type VI _h is discussed. It is known that solutions of type VI _h cannot approach isotropy asymptotically at large times. Indeed the present class of solutions become asymptotic to an anisotropic vacuum plane wave solution. Nevertheless, for these solutions the initial anisotropy can decay, leading to a stage of finite duration in which the model is close to isotropy. Depending on the choice of parameters in the solution, this quasi-isotropic stage can commence at the initial singularity, in which case the singularity is of the type known as isotropic or Friedmann-like. The existence of this quasi-isotropic stage implies that these models can be compatible in principle with the observed universe.     

Dark Energy and Global Rotation of the Universe

We discuss the problem of universe acceleration driven by global rotation. The redshift-magnitude relation is calculated and discussed in the context of SN Ia observation data. It is shown that the dynamics of considered problem is equivalent to the Friedmann model with additional non-interacting fluid with negative pressure. We demonstrate that the universe acceleration increase is due to the presence of global rotation effects, although the cosmological constant is still required to explain the SN Ia data. We discuss some observational constraints coming from SN Ia imposed on the behaviour of the homogeneous Newtonian universe in which matter rotates relative local gyroscopes. In the Newtonian theory _r,0 can be identified with ^,0 (only dust fluid is admissible) and rotation can exist with _r,0 =^,0 0. However, the best-fit flat model is the model without rotation, i.e., ^,0 =0. In the considered case we obtain the limit for ^,0>-0.033 on the confidence level 68.3. We are also beyond the model and postulate the existence of additional matter which scales like radiation matter and then analyse how that model fits the SN Ia data. In this case the limits on rotation coming from BBN and CMB anisotropies are also obtained. If we assume that the current estimates are _m,0 ~ 0.3, _r,0 ~ 10^-4, then the SN Ia data show that ^,0 -0.01 (or ₀ > 2.6 · 10^-19 rad/s). The statistical analysis gives us that the interval for any matter scaling like radiation is _r,0 ( - 0.01, 0.04).     

Nonsingular cosmological model with matter creation and entropy production

The study of nonsingular cosmological models [4] based on a theory of gravitation in flat space-times [1] is continued. For a radiation free universe the solution of the model is given analytically. Under the assumption that entropy cannot decrease the cosmological constant must be zero. At the beginning of the universe all energy is in the form of gravitation. The universe contracts. Matter and radiation are created out of gravitational energy and entropy is produced. The contraction stops and then the universe expands without limit. The creation of matter continues producing entropy but today the production of matter and entropy is negligible. The density parameter ₀ 1, i.e. there must be missing mass in the universe. The flatness and the homogeneity problem are solved.     

New approaches for inflationary cosmology

Extended and hyperextended inflationary models of the universe have been developed which avoid the extreme fine-tuning required by all previous approaches. The models also generate a new source of inhomogeneities that affect large-scale structure. The most surprising feature is the role that inflation can play in altering the nature of the gravitational force.This essay received the second award from the Gravity Research Foundation, 1990 —Ed.     

Cosmological Dynamics of the Tachyon with an Inverse Power-Law Potential

We investigate tachyon dynamics with an inverse power-law potential V () ^–. We find global attractors of the dynamics leading to a dust behavior for > 2 and to an accellerating universe for 0 < 2. We study linear cosmological perturbations and we show that metric fluctuations are constant on large scales in both cases. In the presence of an additional perfect fluid, the tachyon with this potential behaves as dust or dark energy.