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1.
The photoproduction of a neutrino-antineutrino pair at polarized electrons is analyzed, taking account of the spin states of the recoil electrons. Expressions are found for the probabilities in the limiting cases of high (e0E0/m0) = 1 and low 1 intensities of the incident electromagnetic wave. It is shown that a radiative polarization of the electron beam is induced during the emission of the neutrino pair.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 11, pp. 45–49, November, 1970.The authors thank the participants of the seminar conducted by Professor A. A. Sokolov for discussion.  相似文献   

2.
, , . , . , - , , [1], .
On the damping of phase oscillations in a weak-focusing synchroton
An equation of the phase oscillations in a weak-focusing synchroton is derived for the case that an arbitrary high-frequency field of sinusoidal time dependence is distributed on the circumference of the accelerator. It is shown that the damping of phase oscillations is practically independent of the shape of the high-frequency field. From this we get the special case that any adjustments to the accelerator gaps, considered for example in [1], are useless.
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3.
Killing vectors give the linear first integrals of the geodesic equations on Riemannian manifolds and spacetimes, while Killing tensors give the quadratic, cubic, and higher-order first integrals. Here it is shown that the Lie algebra of Killing vectors,, is extended by Killing tensors into a graded algebra,. This sheds some light on the comment by Xanthopoulos [1] on the apparent scarcity of irreducible Killing tensors. Examples are presented of the graded algebras when is abelian and when is nonabelian.  相似文献   

4.
. , 760 mm . .
Formation of cathode spots and current density distribution in cathode spots of short-time high-intensity electric discharge
The connection between the current density distribution in a spot and the vapour jets was found for a short-time high-intensity electric discharge by studying the structure of partial cathode traces and measuring the current density on the cathode. The variation of the current density on the spot with the current gradient was also found and the etching of the cathode surface with ionic bombardment at a pressure of 760 mm Hg was observed.
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5.
Nuclear emulsions were used to study the energy spectrum and forward-backward asymmetry of neutrons from the Co59(p,n) reaction forE p 6·5 MeV. It was found that the decay of the compound nucleus makes a maximum contribution of 50% to the reaction yield. Energies of some excited states of the Ni59 nucleus were also determined.
Co59(p,n) E p 6,5 MeV
- Co59(p,n) E p 6,5 MeV. , 50%. , Ni59.


The authors would like to thank all those who helped in this work, particularly all members of the cyclotron group of the Nuclear Research Institute of the Czechoslovak Academy of Sciences, who so willingly helped with the irradiation, and H. Koutová from the Faculty of Technical and Nuclear Physics, who carefully measured the emulsions. Our thanks are also due to R. Krejová from the Faculty of Technical and Nuclear Physics for developing the emulsions and J. Kopecký from the Nuclear Research Institute for providing the cobalt target.  相似文献   

6.
, . 6,5 . 3,6–4,52 :P(40 ) = 0,30±+ 0,05;P(45/)=0,36±0,07;P(50/)=0,33±0,06;P(60/)=0,20±0,05. , , .
The measurement of the polarization of protons scattered elastically on carbon
The polarization of protons scattered elastically on carbon was measured by means of a cyclotron proton beam accelerated to 6.5 MeV. The following angular distribution was found in the energy interval from 3.60 to 4.52 MeV:P(40 lab )=0.30±0.05;P(45 lab o )=0.36±0.07;P(50 lab )=0.33±0.06;P(60 lab )=0.20±0.05. The results were compared with calculations given in the literature.
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7.
For automorphism groups of operator algebras we show how properties of the difference t – ' t are reflected in relations between the generators , . Indeed for a von Neumann algebraM with separable predual we show that if t – 't 0.28 for smallt, then = 0(+)°-1 where is an inner automorphism ofM and is a bounded derivation ofM. If the difference t – ' t =O(t) ast ; 0, then = + and if t – ' t 0.28 for allt then =. We prove analogous results for unitary groups on a Hilbert space andC 0,C 0 * groups on a Banach space.This paper subsumes an earlier work of the same title which appeared as a report from Z.I.F. der Universität BielefeldWith partial support of the U.S. National Science Foundation  相似文献   

8.
The possibility of explaining the existence of a surface layer on BaTiO3 crystals by the presence of Schottky defects in the crystal is investigated. The magnitude of the potential difference between the surface and the interior of the crystal and the thickness of the surface layer, which at temperatures of over 400°C agrees with the measured values, are calculated for the cubic phase from a simplified ionic model.
BaTiO3
iO3 . , 400° .


In conclusion the author would like to thank Dr. M. Trlifaj and V. Janovec, candidates of physics and mathematics, for valuable remarks.  相似文献   

9.
A study was made of the influence of the relative humidity (from 0.5–90%) on the surface conductivity of bothp- andn-type germanium having differing resistivity. It was. found that the range of changes in the surface potential did not depend on the volume properties of germanium. An analysis of the experimental results shows that the surface potential has values approximately in the range from s =–3kT/q to s =+5kT/q for a change in humidity from 0.5 to 90%. Assuming that the Fermi level changes on the outer side of the oxide layer by approximately the same value as on the germaniumgermanium oxide boundary as a result of the increase and decrease of slow states, it follows that the levels of the slow centres are considerably distant from the Fermi level during the whole humidity range. It is also shown that on the first monomolecular layer of adsorbed water there is an increment of (7.5±0.8) x 1010 donor levels per cm2. This increase in levels either decreases with the number of adsorbed monomolecular layers of water and for 90% humidity has approximately the value 2×1010 cm–2 or remains almost unchanged with the number of layers, if it is assumed that for s =6.0kT/q the Fermi level passes through the centres of adsorbed water.
0,5 90% p n. . , s =– 3kT/q s =+ 5kT/q 0,5 90%. , - , , . , (7,5 ±0,8). 1010 cm2. 90% . 2. 1010 cm–2 , , , s =6,0kT/q .


In conclusion the author thanks Dr. J. Taue for instigating this work and S. Koc, C. Sc., for remarks and the interest with which he followed the work. He also thanks A.Müller for measuring the Hall constant in the samples.  相似文献   

10.
The paper describes tails and side-bands observed on the diffraction patterns of samples after diffusion heating. The origin of tails is explained by the presence of vacancy clusters. Side-bands on X-ray patterns of an Au-Pt sample are interpreted in terms of a pre-precipitate structure or of a metastable phase in the region rich in gold.Thanks for valuable advice are due to RNDr. M. ernohorský CSc., whose suggestions gave rise to this paper.  相似文献   

11.
We performed DFWM spectroscopy on X –1+A 1+ transitions in NaH produced in an indirect photochemical reaction between Na(3p) and H2 and detected v=1, 2 and 3 ground state vibrational levels of NaH molecules, whereas with resonance enhanced CARS, we observed v=0 levels only. This different sensitivity can be explained by considering the Franck-Condon-factors and the relevant damping coefficients for the corresponding transitions in the NaH molecule. Time resolved DFWM spectroscopy showed that NaH(v=1) molecules effectively live much longer than Na(3p) atoms which merely follow the laser excitation pulse.  相似文献   

12.
0,6 25 . , , . , 13,4 20,4 , , , . . , . .
A contribution to the absorption spectrum of amorphous selenium in the infra-red region
The absorption spectrum of amorphous selenium was measured in the region of 0·6 to 25 on samples of high purity and homogeneity. The absorption bands of amorphous and liquid sulphur were also measured in the same wave-length region. The measurements showed that the absorption bands 13·4 and 20·4 , appearing in the spectrum of amorphous selenium, are its intrinsic absorption bands and are not caused by impurities, as some authors think. The similarity between the infra-red spectra of selenium and sulphur is shown.
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13.
Zusammenfassung Es werden die zwei einfachsten Fälle der Exoelektronenemission untersucht und auf Grund dessen geeignete Verfahren zur Verarbeitung der Versuchsergebnisse vorgeschlagen.
.
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14.
For an operator,A, with cyclic vector , we studyA+P, whereP is the rank one projection onto multiples of . If [,] spec (A) andA has no a.c. spectrum, we prove thatA+P has purely singular continuous spectrum on (,) for a denseG of 's.Research partially supported by DGAPA-UNAM and CONACYT.This material is based upon work suported by the National Science Foundation under Grant No. DMS-9207071. The Government has certain rights in this material.This material is based upon work supported by the National Science Foundation under Grant No. DMS-9101715. The Government has certain rights in this material.  相似文献   

15.
Every convex subset of a locally convex Hausdorff space (X, ) is equipped with the (-algebra generated by its-relatively open subsets. Within the set () of probability measures on two particular convex subsets are considered: (a) the set s () of probability measures with a separable support, and (b) the set c () of probability measures with a compact convex support. If is the base of a cone inX, then there exists an affine barycenter map from c () onto whose composition with the natural embedding of in c () yields the identity map on , and every-continuous affine transformation of can be represented by an affine transformation of c () that is induced by a Markov kernel. If (X, ) is a Banach space and is a closed, bounded, generating cone base inX that is contained in a hyperplane, then analogous results are obtained with respect to s (). Since the state spaces considered in noncommutative measure theory are cone bases and every change in time of an empirical system can be thought of as an affine transformation of the associated state space (Schrödinger picture), the existence of these representation theorems implies that the time evolution of general empirical systems can be described by dynamical concepts borrowed from classical probability theory.  相似文献   

16.
The paper is devoted to a study of cyclotron instability ( e) of two opposite beams of electrons from the aspect of the quasilinear effects. For this case of instability the authors evolve the diffusion equation in the velocity space for an averaged distribution function. They estimate the relaxation times , z of the spreading of the distribution function in the velocity space. At the end of the paper, they compare their results with an experiment described by M. Seidl and P. unka [Phys. Letters11 (1964), 31].  相似文献   

17.
For each number between the lower and the upper rotation number of the Birkhoff attractor of a dissipative monotone twist map, there is a periodic or quasi-periodic orbit with rotation number .  相似文献   

18.
The applicability of Tiller's considerations on the production of dislocations is proved. The density of dislocations appearing during impurity microsegregation increases with increasing rate of growth as a consequence of the corresponding change in the effective distribution coefficient. The real value of C at the microsegregation boundaries is at least twice as great as the average value of the concentration of impurities in the crystal in question.
. , , . C , .
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19.
In terms of the Dirac operator P, we introduce on any field a first-order operator D and show that the operator (–) on the spinors (=(n/4(n–1))R; dim W=n) is positive. By means of a universal formula, we show that, on a compact spin manifold of dimension 3, the Hijazi inequality [8] holds for every spinor field such that (P, P) = 2(, ) (=const.). In the limiting case, the manifold admits a Killing spinor which can be evaluated in terms of . Different properties of spin manifolds admitting Killing spinors are proved. D is nothing but the twistor operator.  相似文献   

20.
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