Production of neutral mesons in the reaction12C+12C at 2 GeV/u

A systematic study of neutral meson production in heavy-ion reactions at 2 GeV/u was started with a¹²C+¹²C experiment using the photon spectrometer TAPS. Special emphasis is put on the possible observation of the-meson in a heavy-ion reaction exploiting the decay channel ⁰.Presented at the International School-Workshop Relativistic Heavy-Ion Physics, Prague (Czech Republic), 19–23 September 1994.     

On the photo-electroluminescence of ZnS-Cu

The influence of weak ultra-violet irradiation on the brightness waves of electroluminescence is investigated for two types of ZnS-Cuphosphors. The observed effects (increase in brightness in the primary peak and its phase shift, the disappearance of the secondary peak) are explained on the basis of present-day conceptions on electroluminescence.

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ZnS-Cu

ZnS-Cu. ( , ) .

     

ИССЛЕДОВАНИЕ ЭРОЗИЙ НОГО ДЕЙСТВИЯ ИМПУЛЬ СНЯХ ЭЛЕКТРИЧЕСКИХ РАЗРЯ ДОВ С СЛАБЫМ ТОКОМ

50–100 , 1–2 1–10 . - . - . , , - . -.     

Orthospaces and quantum logic

In this paper we construct the ortholattices arising in quantum logic starting from the phenomenologically plausible idea of a collection of ensembles subject to passing or failing various tests. A collection of ensembles forms a certain kind of preordered set with extra structure called anorthospace; we show that complete ortholattices arise as canonical completions of orthospaces in much the same way as arbitrary complete lattices arise as canonical completions of partially ordered sets. We also show that the canonical completion of an orthospace of ensembles is naturally identifiable as the complete lattice of properties of the ensembles, thereby revealing exactlywhy ortholattices arise in the analysis of tests or experimental propositions. Finally, we axiomatize the hitherto implicit concept of test and show how they may be correlated with properties of ensembles.     

Form of the Frequency Spectrum of Fluctuating Radiation in the Case of Interferometric Reception During Experiments on Radio Sounding of the Solar Corona

We study theoretically the profile of a spectral line of radiation which is received by an interferometer after propagation through a medium with developed turbulent structure. We derive a formula describing the resulting frequency spectrum of an initially monochromatic radiation after its propagation through a multi-scale medium with strong large-scale and weak small-scale irregularities. It is shown that the frequency spectrum observed in this case should comprise the main spectral line with Gaussian profile and wings decreasing according to a power law with index dependent on the orientation of the interferometer baseline with respect to the direction of regular drift of frozen-in irregularities of the medium. We analyze distortions of the spectral response of a very-long-baseline interferometer due to the effect of large-scale irregularities of a medium with developed turbulent structure on wideband radiation from extraterrestrial discrete radio sources. It is shown that if the amplitude fluctuations of the received radiation are weak, then the measured frequency spectrum contains information on the drift velocity and the index of the spatial spectrum of interplanetary plasma irregularities with scales from hundreds to thousands of kilometers.     

The elastic coupling between longitudinal and transversal vibrations оf isotropic rods II. Rods of circular cross-section

The new approximative method for calculating the frequencies of longitudinal vibrations of isotropic homogeneous rods described in part I. is used for rods of circular crosssection. Similarly to the rods of rectangular cross-section there does not exist any dead zone of frequencies.

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II.

, I. (. . 366), . , , .

     

The influence of a small electric perturbation on the electroluminescence curve of ZnS-Cu

The influence of a small electric perturbation of variable phase on the brightness wave of alternating electroluminescence of ZnS-Cu is investigated. The results are compared with the model described in [1]. The increase in the number of ionized activators after switching on the electric field is studied and is found to reach equilibrium. after about 50 to 150 sec.

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ZnS-Cu

ZnS-Cu. , [1]. , 50–150 s.

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In conclusion the author thanks M. Mokonová for cooperation in evaluating the results of measurement.     

ИЗЛУЧЕНИЕ ЧЕРЕНКОВА ПРОСТРАНСТВЕННОГО З АРЯДА В ВОЛНОВОДАХ И В НЕОГР АНИЧЕННОЙ СРЕДЕ

, - e . -. , .     

Optical and magneto-optical effects in semi-conductor crystals

The complicated line structure of the fundamental absorption edge and the effect of magneto-optical oscillations (which are general properties of crystals) open up good possibilities for the study of band structure and exciton states.From a survey of the facts observed lately it follows that the real existence of the exciton is almost certain although no experiment has yet been performed, which would provide direct experimental proof of its motion in the crystal. The evidence of the motion of excitons in the crystal can be determined from effects based on spatial dispersion effects. The observed optical anisotropy of absorption in a Cu₂O cubic crystal (due to spatial dispersion) and the quadrupole character of the exciton linen=1 confirm the motion of exciton through the crystal.The fine structure of the spectral curve for photoconductivity (an effect that is also common to all crystals), which is directly connected with the exciton absorption structure, also testifies to the motion of excitons.The exciton structure of the absorption edge and also the connected effect of edge emission enable the band structure and its splitting to be studied.The determination of the splitting of the exciton lines and edge of continuous absorption under the influence of oriented elastic deformation and the study of the state of polarization of the split components provides a new method for the study of band structure.The study of the Zeeman effect for lines of exciton, absorption in crystals can supply data on the exciton motion and on the complicated band structure in crystals. Special detailed data on the band structure can be obtained from studies in polarized light. From the effect of magneto-optical oscillations we can decide with great exactness the band width of the forbidden zone and obtain data which are in good agreement with those obtained by other methods.

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- , , . , , , , . , . — —, , n=1 . — , , — , . , - . () , . , , , , . - . . , , .

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Address delivered at International Conference on Semi-conductor Physics, Prague, Czechoslovakia, September 1960.     

Stability and structure of Newtonian gravitars

The solution r² for a scalar field (gravitational constant), which is asymptotically exact for supercompact configurations and which Saakyan and Mnatsakanyan obtained from the numerical solution of the hydrostatics equations in the Newtonian approximation of the Jordan-Brans-Dicke theory, is used to study the gravitational stability of such configurations. We have found the stability condition 2/3 for polytropic configurations ( is the polytropic exponent) instead of 4/3, which is known for configurations of low compactness. Analytic solutions of the equations of internal structure are found for configurations which are intermediate with respect to stability (=2/3) and for some other important series of configurations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 98–102, July, 1982.In conclusion, the present author expresses his indebtedness and gratitude to V. N. Ponomarev, for assistance in executing the work.     

Current distributions in a two-dimensional random-resistor network

The current and logarithm-of-the-current distributionsn(i) andn(ln i) on bond diluted two-dimensional random-resistor networks at the percolation threshold are studied by a modified transfer matrix method. Thek th moment (–9k8) of n(ln i) i.e., ln i&^k, is found to scale with the linear sizeL as (InL)^(k). The exponents (k) are not inconsistent with the recent theoretical prediction (k)=k, with deviations which may be attributed to severe finitesize effects. For small currents, ln n(y)–, yielding information on the threshold below which the multifractality of (i) breaks down. Our numerical results for the moments of the currents are consistent with other available results.     

Static and Vibrational Properties of Transition Metals

A model pseudopotential depending on an effective core radius but otherwise parameter free is proposed to study the equation of state by incorporating the s-d hybridization effects. Very recently proposed screening function due to Sarkar et al has been used to obtain the screened form factor. The equations of state for Cu, Ta, Mo, W and Pt have been studied up to the pressure of 1000 GPa. The vibrational properties such as phonon dispersion curves (in q and r space), phonon density of states, mode Grüneisen parameters, maximum frequency _max, mean frequency , ^21/2 = (/ ^-1)^1/2 and fundamental frequency ² and static properties such as dynamical elastic constants of rhodium and iridium are also calculated. The theoretical results are compared with experimental findings wherever possible. A good agreement between theoretical investigations and experimental findings has confirmed our formulation.     

Logically independent von Neumann lattices

Three definitions of logical independence of two von Neumann latticesP₁,P₂ of two sub-von Neumann algebras ₁, ₂ of a von Neumann algebra are given and the relations of the definitions clarified. It is shown that under weak assumptions the following notion, called logical independence is the strongest:A B 0 for any 0 A P₁, 0 B P₂. Propositions relating logical independence ofP₁,P₂ toC ^*-independence,W ^* independence, and strict locality of ₁, ₂ are presented.     

Zero value of the Schwarzschild mass for an asymptotically Euclidian system of gravitational waves

A class of the asymptotically Euclidian space-times is shown to exist for which the Schwarzschild mass is equal to zero. The coordinate atlases of these space-times satisfy two additional conditions: _k (-gg ^0k )=0 and _ik ⁰ _0g ^ik - _ik ^k _0g ⁰ⁱ =0. In aT-orthogonal metricgs ²=g ₀₀ dt ² -g dx dx these conditions take a simple form: ₀(detg )=0 and (₀ g )(₀ g )=0.     

Eigenfunctions of the Koch snowflake domain

We obtain non-tangential boundary estimates for the Dirichlet eigenfunctions _n and their gradients {_n } for a class of planar domains with fractal boundaries. This class includes the quasidiscs and, in particular, snowflake-type domains. When applied to the case when is the Koch snowflake domain, one of our main results states that {₁()} tends to or 0 as approaches certain types of boundary points (where ₁ > 0 denotes the ground state eigenfunction of the Dirichlet Laplacian on ). More precisely, let Ob (resp., Ac) denote the set of boundary points which are vertices of obtuse (resp., acute) angles in an inner polygonal approximation of the snowflake curve . Then given Ob (resp., Ac), we show that {₁()} (resp., 0) as tends to in within a cone based at . Moreover, we show that blowup of {₁} also occurs at all boundary points in a Cantor-type set. These results have physical relevance to the damping of waves by fractal coastlines, as pointed out by Sapovalet al. in their experiments on the Koch drum.Research partially supported by the National Science Foundation under Grant DMS-9207098.     

Photostability of Molecules of Aromatic Amines in a Polymeric Matrix

In the temperature range T = 5–295 K, the spectralluminescent properties and curves of thermostimulated luminescence (TSL) of molecules of triphenylamine (TPA), trirtolylamine (TTA), triranisolamine (TAA), and N,N'diphenylbis(3methylphenyl)(1,1'biphenyl)4,4'diamine (TPD) in polystyrene and 4Brpolystyrene matrices have been investigated. It has been found that photoirradiation at room temperature in the region of the lowest electron transition of molecules leads to a decrease in the intensities of the luminescence, photoluminescence, and TSL bands, as well as to the formation of new deep traps for charge carriers. At equal irradiation doses these changes in TPD are noticeably less pronounced than in TPA, TTA, and TAA. The higher photochemical stability of TPD molecules compared to TPA, TTA, and TAA is attributed to the difference in the mechanisms of nonradiative deactivation of the triplet states of molecules.     

Quantum field theory and the coloring problem of graphs

The ^k theory is compared with the multilinear theory of scalar fields ₁, ₂, ..., _k having the same mass as that of . In particular, it is shown that Feynman integrals encountered in the ³ theory are not necessarily present also in the _{1 2 3} theory, but they are if they correspond to planar Feynman graphs having no tadpole part. Furthermore, a necessary and sufficient condition for the presence of a ³ Feynman integral in the _{1 2} ² theory is found. Those considerations are applications of graph theory, especially of the coloring problem of graphs, to Feynman graphs.     

БЕТАТРОННЫЕ КОЛЕБАН ИЯ В УСКОРИТЕЛЕ С ОБЩИМ ПОЛЕМ I

, . . . , , . , . , . .

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Betatron oscillations in an accelerator with a general field I

The paper gives a linear theory of equilibrium trajectories in an accelerator with a generalized magnetostatic field, the components of which are defined on a general rotation surface. Equations of motion of the particles in natural coordinates are derived with respect to the change in energy and dissipative force. A system of equilibrium trajectories is found in the general form. Conditions for the field components on the reference surface, necessary for the existence of equilibrium trajectories, for the conservation of their geometric similarities and for maintaining the constancy of the frequencies of the betatron oscillations, are derived. A condition is also derived which must be satisfied by the reference surface in order to conserve constant circular frequency of the particles. It is seen that it is not possible to find a field for an accelerator with an exactly constant circular frequency and with constant frequencies of the betatron oscillation in the relativistic energy region. An ultra-relativistic cyclotron with such properties is realizable.

     

Interaction between the nucleon and muon currents in elastic neutrino-nucleon interactions

The spin relations of neutrino-nucleon interaction with the formation of a muonv(V) N N are investigated within the framework of the two-component and four-component theories of two neutrinos under the assumption of a point neutrino. The difference between the predictions of the two theories is identified. It is shown that the four-component theory of two neutrinos, unlike the two-component theory, accommodates the V + A variant of interaction between the muon current (v) and the barion current.The authors are grateful to Prof. A. A. Sokolov and to R. Sh. Yakh'yaev for evaluating the results.     

The Becker-Döring cluster equations: Basic properties and asymptotic behaviour of solutions

Existence and uniqueness results are established for solutions to the Becker-Döring cluster equations. The density is shown to be a conserved quantity. Under hypotheses applying to a model of a quenched binary alloy the asymptotic behaviour of solutions with rapidly decaying initial data is determined. Denoting the set of equilibrium solutions byc ⁽⁾, 0 _s , the principal result is that if the initial density _{0 s} then the solution converges strongly toc ^(o), while if ₀ > _s the solution converges weak* toc ^(s). In the latter case the excess density ₀– _s corresponds to the formation of larger and larger clusters, i.e. condensation. The main tools for studying the asymptotic behaviour are the use of a Lyapunov function with desirable continuity properties, obtained from a known Lyapunov function by the addition of a special multiple of the density, and a maximum principle for solutions.