ИНТЕРФЕРЕНЦИЯ ДВУХ Э СТЕСТВЕННYХ ПУЧКОВ СВ ЕТА, ПРОШЕДШИХ ЧЕРЕЗ ОПТИ ЧЕСКИ АКТИВНУЮ) СРЕДУ

, .     

Wavelength distribution of X-rays in the focus of a monochromator and an estimate of the influence of this distribution on precision measurements of lattice constants

Wavelength distribution in the focus of a Johansson type monochromator is computed assuming the tube focus emissivityG(), reflection curveR() and wavelength distribution of the incident radiationJ(-₀) are known. It is shown e.g. that the centre of gravity may be shifted in accordance with the position of the crystal on the focal circle which may considerably influence precision measurements of lattice parameters.

---

, G(,) R() J(-₀) . , , , .

---

---

The author is grateful to Z. Hemanová for carrying out all the computations very carefully.     

Raman effect of light on argon atoms

Scalar scattering of light on the 3p and 3s subshells of the argon atom (Stokes scattering) and anti-Stokes scattering on the excited 4p and 4s states of argon are examined in the Hartree-Fock approximation. The calculation is made in a velocity form and in a length form. It is shown that the value in the r form is 1.5–2 times greater than in the form.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 36–42, January, 1977.     

Elimination of variables in simple laser equations

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.     

The distribution of neutron density in the vicinity of a partly inserted black rod in two-group approximation

The neutron density in the vicinity of a black cylindrical rod partly inserted in a bare reactor is calculated and illustrated by a numerical example. The starting point is a two-group diffusion theory approximation. While the dependence of the effect of the rod on the insertion depth can be calculated simply by means of perturbation theory, the question of the neutron density estimate in the vicinity of the rod is considerably more difficult and in some considerations the estimate of the neutron density caused by the presence of the rod is indispensable. The method makes it possible to determine the reactivity value of the rod in dependence on the insertion depth and especially the neutron density deformation in the vicinity of the rod.

---

()

. , . , , . , . [1] . .

---

---

In conclusion the author thanks J. Svato for help in carrying out the numerical calculations.     

Химическая сенсиБил изация фотографичес кой эмульсии

---

Chemical sensiblilisation of photographic emulsion

---

, 7. V. 1953 .     

Traffic Jams in a Lattice-Gas Model

We propose a simple lattice-gas model characterized by two states of atoms, the thermalized state, which is the same as in the standard lattice-gas model, and the running state, where the atoms jump in one direction only. The model exhibits the existence of traffice jams (bunching of thermalized atoms in compact groups), the nonlinear dependence of mobility on the jump probability, and the hysteresis.     

СЕРНИСТЫЙ ТЕЛЛУР — ПО ЛУПРОВОДИОЕ СОЕДИНЕ НИЕ

, , , , .     

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.

---

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.

---

---

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

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

---

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

---

, .

---

, -.     

ОПРЕДЕЛЕНИЕ ПОСТОЯН НЫХ ДВУХПАРАМЕТРОВЫ Х РЕШЕТОК МЕТОДОМ ОТНО ШЕНИЙ

. . - 10^–4.     

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.

---

, . . . , ( ), , . , . . , . 22, 23, 24, 25 26 , 24 . . .

---

---

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

Influence of Solvent Polarity and Viscosity on Nonradiative Processes in Oligothiophenes with Intramolecular Charge Transfer

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.     

БЕТАТРОННЫЕ КОЛЕБАН ИЯ В УСКОРИТЕЛЕ С ОБЩИМ ПОЛЕМ I

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

---

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.

     

ВЛИЯНИЕ ПОЛНОГО ОТРА ЖЕНИЯ НА ДИАФРАГМЕ СОЛЛЕРА НА РАЗРЕШАЮШ УЮ СИЛУ РЕНТГЕНОВСКО ГО СПЕКТРОГРАФА

- - , , , . - , -.     

On the massive sine-Gordon equation in all regions of collapse

The ultraviolet stability for the cosine interaction in two dimensions and finite volume is rederived for values ² [4, 32/5[ and proven for the remaining ² [4, 8[ by using renormalization group methods developed in [G, GN1] to portray renormalized effective potentials arising from a multiscale decomposition.Supported by the Studienstiftung des Deutschen VolkesSupported in part by the Schweizerischer Nationalfonds     

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

, - e . -. , .     

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.     

The quantum efficiency of the internal photo-electric effect in indium antimonide

A method is described for measuring the relative quantum efficiency of the internal photo-electric effect in semi-conductors by simultaneously measuring the photo-magnetoelectric and photo-conductive effect. The results of measurements on indium antimonide are given. The quantum efficiency begins to increase if the energy of the photon exceeds 0·47 eVat room temperature. The quantum efficiency as a function of the energy of the photon is analysed on the basis of the conception of impact ionization and it is shown that a study of the structure of this curve can supply information on the, band structure of a semi-conductor in the region of high energies of electrons and holes.

---

. . , 0,47 eV . , .

---

---

The authors thank M. Závtová and M. Vantuchová for efficient help with the measurements, K. mirous and V. Vrchovská for preparing the material, E. Antoník for critical remarks and M. Matyá and A. Müller for determining the constants of the material.     

Влияние давления на а бсорбцию галогенидо в серебра. Часть II

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