On the lunar variation of cosmic radiation

The paper investigates the lunar variation of the intensity of cosmic radiation as assumed by E. Bagge and O. Binder. By evaluating the data of two stations on the same meridian circle (Rome and Makapuu Point) we reach the conclusion that this lunar variation is only apparent. The result obtained by E. Bagge and O. Binder could be caused by a small difference between the diurnal period and the assumed lunar variation. This statement is demonstrated by searching for variations with periods 22, 23, 24, 25 and 26 hours which also differ little from the 24-hour period of the diurnal variation. For these calculations the data of the station Mt. Norikura were used.

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In conclusion the authors wish to express their thanks to J. Sláma for his valuable help in the numerical calculations.     

Experimentelle Untersuchungen über das Verteilungsgesetz der Ferromagnetischen Bereiche nach dem Kriterium der Koerzitivkraft

Zusammenfassung Aus Messungen der inneren Reibung in magnetischen Feldern, die durch das Überlagern eines magnetischen Wechselfeldes über ein magnetisches Gleichfeld zustande gekommen sind, werden Schlußfolgerungen gezogen über die Art, wie sich die Verteilung der ferromagnetischen Bereiche nach dem Standpunkt der Koerzitivkraft im Magnetisierungsprozeß in einem magnetischen Gleichfeld verändert. Aus Messungen der inneren Reibung in magnetischen Wechselfeldern mit gleicher Amplitude aber verschiedenen Frequenzen wird die Schlußfolgerung gezogen, daß die Wände jener Bereiche, welche verschiedene Koerzitivkräfte haben, erzwungene Schwingungen mit verschiedener Geschwindigkeit aufweisen.

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On Spherically Symmetric Minimally Coupled Brane Worlds

For a static, spherically symmetric brane in the framework of the RS2 concept, we study the conditions under which the 4D tensor E _v, arising from the 5D Weyl tensor, vanishes on the brane. Gravity on the brane is then decoupled from the bulk geometry, it is the so-called minimally coupled brane world (MCBW). Assuming E _v =0 in the whole bulk, we try to solve the 5D Einstein equations G _AB + _5gAB =0 and obtain an overdetermined set of equations for functions of the radial coordinate. Some special solutions are found, among which are the well-known black string solution with the Schwarzschild metric on the brane and its generalizations with Schwarzschild–(A)dS on-brane metrics. It is concluded that a MCBW can be embedded, in general, in a bulk where E_v is not identically zero but only vanishes on the brane. We also present some previous results on the general properties of scalar fields on the brane and give an example of a wormhole supported by a scalar field in a MCBW.     

ИЗМЕРЕНИЕ ЦИКРУЛЯРН ОЙ ПОЛЯРИЗАЦИИ γ-КВАН ТОВ, ИСПУСКАЕМЫХ ЯДРАМИ П ОСЛЕ ЗАХВАТА ПОЛЯРИЗ ОВАННЫХ ТЕПЛОВЫХ НЕЙТРОНОВ

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Measurement of the circular polarization of gamma-quanta emitted from the nuclei after the capture of polarized thermal neutrons

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, .

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, -.     

Локалъная чувствите лъностъ фотокатодов фотоумножителей

. . .

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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.

     

Влияние давления на а бсорбцию галогенидо в серебра. Часть II

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

ОПРЕДЕЛЕНИЕ ПОСТОЯН НЫХ ДВУХПАРАМЕТРОВЫ Х РЕШЕТОК МЕТОДОМ ОТНО ШЕНИЙ

. . - 10^–4.     

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

, - e . -. , .     

Химическая сенсиБил изация фотографичес кой эмульсии

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Chemical sensiblilisation of photographic emulsion

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, 7. V. 1953 .     

The complex conductivity of the plasma of a d-c glow discharge in Ne

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.

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[1] , . , .

     

Properties of certain collective variables used in high-energy physics

The properties of the collective variables _m (m=1, 2), T, and P, which are used extensively in high-energy physics, are investigated. It is shown that the variables _m are intimately related to the dipole (m=1) and quadrupole (m=2) moments. A general equation is given for calculating the variance of _m for azimuth angles having any probability density function; well-known special cases are deduced from this equation. Two collective variables, the oblateness T and the prolateness P, have the property of stability when the momentum distribution of particles in the ground state is symmetric about some axis. This property should be useful in searches for events of the jet and vortex type.Deceased.A. R. Beruni State Technical University, Tashkent. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 79–83, March, 1993.     

Logical independence in quantum logic

The projection latticesP(₁),P(₂) of two von Neumann subalgebras ₁, ₂ of the von Neumann algebra are defined to be logically independent if A B0 for any 0AP(₁), 0BP(₂). After motivating this notion in independence, it is shown thatP(₁),P(₂) are logically independent if ₁ is a subfactor in a finite factor andP(₁),P(₂ commute. Also, logical independence is related to the statistical independence conditions called C^*-independence W^*-independence, and strict locality. Logical independence ofP(₁,P(₂ turns out to be equivalent to the C^*-independence of (₁,₂) for mutually commuting ₁,₂ and it is shown that if (₁,₂) is a pair of (not necessarily commuting) von Neumann subalgebras, thenP(₁,P(₂ are logically independent in the following cases: is a finite-dimensional full-matrix algebra and ₁,₂ are C^*-independent; (₁,₂) is a W^*-independent pair; ₁,₂ have the property of strict locality.     

On the electroluminescence of powdered zinc sulphide layers

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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Massive spin-two particle in a gravitational field

The spin-two particle is described by a symmetric tensorh subject to the subsidiary conditionsh = h =0. Their covariant generalization and the wave equation have been obtained directly from the Eulerian variational equations by algebraic methods only. In addition to the tensor fieldh a symmetric third-rank tensor = as well as a vector fieldA have been added, neither of which enter in the final result. The Lagrangian function is taken as a linear sum of all combinations which can be constructed from these functions, as well as terms involving the curvature tensor and its two possible contractions. Variation with respect toh , andA independently gives the Euler equations. Combining the various trace equations and choice of arbitrary constants yields the subsidiary conditions, while the Euler equations themselves give the connection between the auxiliary functions and the tensorh as well as the generalization of the wave equationD D h + 2R h -R h -R h +g R h +Rh =m ² h Finally, variation with respect tog yields the energy-momentum tensor.     

The semi-conducting properties of CdSnAs2

The paper gives the results of measuring the temperature dependence of the electrical conductivity(T), the Hall coefficientR _H (T) and the magnetic susceptibility(T) forn-type CdSnAs₂. The effective mass of the electrons was determined by analysis of the measured dependences on the basis of the simple theory for an isotropic non-degenerate semi-conductor. It was found to bem _n /m ₀=2×10^–2 in the intrinsic region and does not depend on the temperature; the energy gap ise _g ⁰=0·26 eV and the molar susceptibility of the CdSnAs₂ lattice _G ^mol=–112× ×10^–6. The mobility of the electrons in the intrinsic region reaches a value of _n =25 000 cm²V^–1sec^–1 at 500°K and decreases exponentially _n T ^–1.67 with rising temperature. The density of CdSnAs₂ was determined pyknometrically,g9=5·35 g cm^–3. The measurements were made on ann-type polycrystalline sample consisting of crystals a few millimetres in diameter, which at a temperature of 100°K had a free electron concentration ofn _s =6×10¹⁶ cm^–3.

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CdSnAs₂

(T), R _H (T) (T) CdSnAs₂ . m _n /m ₀= =2.10^–2, ; E _G ⁰=0,26 eV, CdSnAs_{2 G} ^mol= =–112.10^–6. 500°K _n =25 000 cm²V^–1sec^–1 , _n T ^–1,67. CdSnAs₂ =5,35 g cm^–3. , , 100°K n _s =6.10¹⁶cm^–3.

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The authors would like to thank Mr. P. Jansa for help in measuring the temperature dependence of the magnetic susceptibility.     

Choice of parameters of an X-ray monochromating unit

In recent papers a way of computing the monochromated wavelength distribution in some current experimental arrangements was presented. In this paper an application is shown for the Johansson monochromating unit. The conditions are indicated for attaining the desired breadth of the monochromated interval and for its maximum intensity. The analysis implies that it is not advantageous to use very narrow foci and that the crystals should be neither very perfect nor very imperfect. The optimum conditions must be found in each case separately.

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. Johansson. , , . , , , . .

     

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.     

Summation formulae in the theory of thin films

On the basis of general summation formulae for light reflected and transmitted by a thin film the author derives formulae for a thin dielectric film, for a thin metallic film and for a system of thin dielectric films. This solution is based on Stokes's principle of reversibility, which is the idea unifying the cases into one theory. In conclusion he gives the solution of a general case, dealing with light reflected and transmitted by a system of thin dielectric and metallic films.

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More inequalities for critical exponents

A variety of rigorous inequalities for critical exponents is proved. Most notable is the low-temperature Josephson inequalitydv +2 2–. Others are 1 1 +v, 1 1 , 1,d 1 + 1/ (for d),dv, ₃ + (for d), ₄ , and _{2m 2m+2} (form 2). The hypotheses vary; all inequalities are true for the spin-1/2 Ising model with nearest-neighbor ferromagnetic pair interactions.NSF Predoctoral Fellow (1976–1979). Research supported in part by NSF Grant PHY 78-23952.     

Ground state of a spin-phonon system. II. Adiabatic limit

The phase transition for a spin in a magnetic fieldB coupled to acoustic phonons by a coupling constant is studied. The caseB1 with an upper cutoff of unity for the phonons is studied systematically by using an adiabatic canonical transformation. In leading order the transition line is at =2/B=1. In the normal phase (<1) the ground-state energy is –B/2 plus a function of that is given explicitly as the solution of a pair theory. In the broken symmetry phase (>1) the energy is the classical energy plus the same function of =1/². It is found that the first derivatives of the energy with respect to and with respect toB have finite jumps across the transition line. Quantum fluctuations in both phases are treated. Higher-order terms are a series of powers of 1/B times functions of . The case of a small transverse fieldB is also studied. The sharp transition disappears and is replaced by rapid variation in a region of order (B₁/B)^2/3 about =1.