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1.
In paper [1] Fang derived an expression for the complex conductivity of plasma assuming that the distribution function of the electrons is Maxwellian and the collision frequency is directly proportional to their velocity. Since the assumptions are approximately satisfied in the positive column of a d-c glow discharge in Ne, the applicability of Fang's relation is investigated for this case.
[1] , . , .
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2.
Let us consider a Lie (super)algebra G spanned by T where T are quantum observables in BV formalism. It is proved that for every tensor c... that determines a homology class of the Lie algebra G the expression c...T...T is again a quantum observable. This theorem is used to construct quantum observables in the BV sigma model. We apply this construction to explain Kontsevich's results about the relation between homology of the Lie algebra of Hamiltonian vector fields and topological invariants of manifolds.  相似文献   

3.
By the methods of luminescence, picosecond spectroscopy, and quantumchemical calculations the mechanisms of electron excitation energy deactivation in some oligothiophenes with intramolecular charge transfer depending on the solvent polarity and viscosity have been investigated. While for 2Npiperidino5(2,2dicyanovinyl)thiophene (PDCVT) the main channel of nonradiative deactivation is the transition to a lower intermediate state with a twisted double bond controlled by the medium viscosity, in the case of (E){2[25piperidino2thienyl]6(trifluoridemethyl)4H4pyranylidene}propanedinitryl (PTFDN) fluorescence quenching is initiated by the solvent polarity. For two other oligothiophenes, 2Npiperidino5cyanothiophene (PCT) and 2Npiperidino5cyanoterthiophene (PCTT), differing in the length of the thiophene chain, we have revealed, along with the effective quenching of fluorescence in shortchain PCT (independent of the solvent polarity and viscosity), an increase in the radiation capacity in PCTT with increasing polarity of the solvent. The possible mechanisms of nonradiative deactivation in the investigated oligothiophenes are discussed.  相似文献   

4.
. . .
The local sensitivity of photo-multiplier photo-cathodes
The influence of the non-uniform distribution of the sensitivity of a photo-multiplier photo-cathode on the spectrum shape of the output pulses from a scintillation detector is studied. Methods of scanning the local sensitivity and determining its distribution function are described. The theory was compared qualitatively with measurement on a slow-neutron detector from a mixture of zinc sulphate and boric acid.
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5.
The paper deals with the collective behaviour of electrons which rotate in a magnetic field used in a betatron. It is shown experimentally that there exists strong interaction between the electrons, which leads to the rapid formation of the equilibrium state with characteristic distribution of the charge density in the cross-section of the toroidal beam. The corresponding relaxation time is of the order of 1 sec. A statistical theory of the equilibrium beam is elaborated. Its main result is that the effective radius of the beam is a function of two parameters, one of which is proportional to the thermal energy of the electrons and the other to the perveance of the beam. The charge contained in a toroidal beam of given effective cross-section is equal to the product of the charge the beam would contain at zero temperature and a coefficient, which is a function of the temperature of the beam. Its value is unity at zero temperature and rapidly decreases with increasing temperature. The cause of cooling of the beam is shown.
, . , , . 1S. . , , — I/(E0/q)3/2 (I — , 0 — q ). , , , , , . . .


Now Institute of Vacuum Electronics, Czechosl. Acad. Sci., Prague.

In conclusion the author thanks J. Luká and L. Hyttych for invaluable help in the experiments, A. Rajský for constructing the electronic apparatus and J. Sokol for preparing the miniature probe.  相似文献   

6.
On the basis of the boundary conditions of the electromagnetic theory an explicit calculation of the absorption in a thin metallic film was carried out with the result that transport and interference components were found to exist. By applying the method to a simple metal-dielectric boundary the physical interpretation was given of the energy balance, which had hitherto been regarded as unclear. It was also explained why the reversibility principle fails when applied to a metal-dielectric boundary.
, . - , . , - .
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7.
In this paper we give a characterization of the modular group of a von Neumann algebra , with a cyclic and separating vector, which provides at the same time a necessary and sufficient condition so that two von Neumann algebras 1 and 2, such that 12, are the mutual commutants, i.e. 1=2.An application is made to the duality property in Quantum Field Theory, and we give a sufficient condition for PCT invariance in a theory of local observables.Partially supported by C.N.R.  相似文献   

8.
9.
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   

10.
11.
12.
The experimental study of the dependence of the electroluminescence brightness on the voltage confirms the correctness of the mechanism of electroluminescence, based on impact ionization in parts of the crystal where the electric field is concentrated. A study of the photoluminescent and electroluminescent spectra of phosphors containing two activators (copper and an element of rare earth) permits the determination of the magnitude of the volume of the crystal in which electroluminescence occurs. A study of the influence of the stored light sum on the brightness of electroluminescence and a study of the rate of growth of the variable and constant components of electroluminescence point to the fact that the excitation is transferred from the region of field concentration to the whole volume of the crystal.
, . - , ( ), , . .
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13.
Let M be a von Neumann algebra acting on a Hilbert space H and H a cyclic and separating vector for M. If there exists a half-sided translation for M, i.e. a continuous unitary group U(t) with U(t)=, a non-negative spectrum fulfilling Ad U(t)M M for t 0 (or 0), then we will show that either M is of type III1 or U(t) is trivial.  相似文献   

14.
15.
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.
-
- , , . , , , , . , . — —, , n=1 . — , , — , . , - . () , . , , , , . - . . , , .


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

16.
Zusammenfassung Es wird die Abhängigkeit des Brechungsindexn von Silizium von der TemperaturT im Wellenlängenbereich 1,1–5,5 und im Temperaturbereich 109–750°K angeführt. Die Abhängigkeitn=f(T) ist unlinear, für tiefe Temperaturen (T170°K) giltnT 2. Theoretisch kann die beobachtete Abhängigkeit nicht unstreitig interpretiert werden, da eine explicite quantenmechanische Beziehung für den Brechungsindex der homeopolaren Kristalle nicht existiert. Es kann jedoch die Lorentzsche klassische Beziehung für Isolatoren angewandt werden. Für diese kann dn/dT numerisch ausgedrückt werden. Die berechneten Werte stimmen befriedigend mit den experimentalen überein. Unsere Ergebnisse sind in guter Übereinstimmung mit der Antoníkschen Theorie der Temperaturabhängigkeit des Brechungsindex der homeopolaren Kristalle.
T =1,1–5,5 109– 750°. n=f(T) , (T170°) nT 2. , . , . dn/dT . . .


Abschließend danke ich Dr. Z. Trousil von dem Inst. f. techn. Physik der Tschechosl. A. d. W., Prag für die gewährung von Silizium, dem Kollegen Irra für polieren des Prismas, Dr. Tauc von demselben Institut dafür, daß er mir einige Messungen in seinem Laboratorium ermöglichte und der Kollegin ilhavá für ihre Hilfe bei den Messungen.  相似文献   

17.
It is shown that according to the Watanabe theory of weak interactions a resonant scattering of electrons by protons must take place. The resonant energy depends on the massm B of the intermediate boson. Form B=2300m e this energy is about 213 MeV in the centre of the mass system (c. m. s.). The energy width at resonance is 1·4 MeV.
, . , , . m B=2300m B , 213 MeV -. 1,4 MeV.


The author would like to thank Professor V. Votruba for suggesting this note and for valuable advice and help during the work.  相似文献   

18.
A physical model is proposed for volitional decision making. It is postulated that consciousness reducesdoubt states of the brain into labels by a quantum-mechanical measurement act offree choice. Elementary doubt states illustrate analogical encodement of information having insufficient resolution from a classical viewpoint. Measures ofcertitude (inner conviction) and doubt are formulated. Adequate propositions for nonclassical statements, e.g., Hamlet's soliloquy, are constructed. A role is proposed for the superposition principle in imagination and creativity. Experimental predictions are offered for positive and negative interference of doubts. Necessary criteria are made explicit for doubting sense information.Wholeness of perception is illustrated using irreducible, unitary representations ofn-valued logics. The interpreted formalism includes nonclassical features of doubt, e.g., scalor representations for imprecise propositions and state changes due to self-reflection. The liar paradox is resolved. An internal origin is suggested for spinor dichotomies, e.g., true-false and good-bad, analogous to particle production.Translated by Valentin Turchin, with editorial assistance by Eddie Oshins; abstract supplied by Eddie Oshins.  相似文献   

19.
The influence of compression on the edge of self absorption of AgBr single crystals was studied. The measurements were performed at a temperature of –180°C. The shift of the edge of self absorption was studied both in the field of elastic and plastic deformations. The shift of the absorption edge towards the UV end of the spectrum was determined in the field of elastic deformations and towards the i.r. end in the field of plastic deformations. After the ending of the deformation and after unloading the crystal the return of the absorption edge towards the original position was observed.
AgBr
AgBr. –180°C. , . , — . .


The author thanks Prof. Dr. L. Zachoval and K. K. Vacek C. Sc. for their interest in this work and for many comments given during the work.  相似文献   

20.
The usual way of obtaining rate equations (RE) and a single equation for the field amplitude (EFA) from the semiclassical laser equations (Lorenz-Haken model) is reexamined by undertaking a systematic elimination procedure developed in synergetics. The RE and EFA are justified in the case 1 (, ) and case 2 (, ), respectively. We show that, because the eliminated variable happens to contain a considerable contribution from an unstable mode, the usual elimination technique in the case 3 (, ) leads to an inconsistency. As important by-products we obtain the RE and EFA for arbitrary cavity relaxation constant (). Some remarks are given on the direct elimination technique in the non-diagonal representation in the study of instabilities.  相似文献   

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