Влияние катодной обл асти на динамические свойства тлеющего разряда в во дороде

. . , , I-om 1957 .     

ПОЛЕ ПЕРЕМЕННОГО ДИП ОЛЯ В НЕОДНОРОДНОМ ПОЛУПРОСТРАНСТВЕ

, . , ₁, ₂. - .     

К В. Ч. НАГРЕВУ РАЗРЕЖЕННОЙ ПЛАЗМЫ

[2]. . , . , . . . .     

Эффективностъ сцинт илляционных счетчик ов для быстрых нейтроно в

, ZnS(Ag) . ZnS(Ag) . Po-Be, Ra-Be Li(d, n), C(d, n), N(d, n), Be(d, n). -, Co⁶⁰, Cs¹³⁷ Ra, , -, Li(p, ). , .     

Der Exzitonenzerfall im elektrostatischen Felde der Störstellen von Ionenkristallen

Zusammenfassung Es wird theoretisch der Prozeß des Exzitonenzerfalls mit Hilfe der Ionisation durch das elektrostatische Feld der Störstelle untersucht. Die Wirkungsquerschnitte werden in zwei Grenzfällen bestimmt: bei einer kleinen und einer großen mittleren freien Bahn des Exzitons, die durch dessen Wechselwirkung mit den Phononen bedingt ist. Die Ergebnisse werden zum Studium des Exzitonenzerfalls an einer Vakanz nach einem Kupferion in Cu₂O-Kristallen mit einem stöchiometrischen Sauerstoffüberschuß verwendet.

---

. : , . Cu₂0 .

     

The thermodynamic limit for a crystal

Consider a crystal with nucleii fixed at the lattice points in ³, interacting by Coulomb forces with quantized electrons in . We prove that the pressure tends to a limit as grows infinitely large.Supported by NSF Grant No. MCS80-03072     

Some critical exponent inequalities for percolation

For a large class of independent (site or bond, short- or long-range) percolation models, we show the following: (1) If the percolation densityP (p) is discontinuous atp _c , then the critical exponent (defined by the divergence of expected cluster size, nP _n (p) (P _c –P)^– asp p _c ) must satisfy 2. (2) or (defined analogously to, but asp p _c ) and [P _n (p _c ) (n ^–1–1/) asn ] must satisfy, 2(1 – 1/). These inequalities for improve the previously known bound 1(Aizenman and Newman), since 2 (Aizenman and Barsky). Additionally, result 1may be useful, in standardd-dimensional percolation, for proving rigorously (ind>2) that, as expected,P _x has no discontinuity atp _c .     

Two-quantum annihilation of polarized positrons

The cross-section for the two-quantum annihilation-in-flight of partially polarized beams of particles, obtained by using the polarization density matrix, is given. The formula includes the special results of L. A. Page [1]. The annihilation of a longitudinally polarized positron with a transversally polarized electron is discussed. Computations are made in a centre-of-mass system with summing over photon polarizations.

---

. . . . . .

---

---

Abbreviated version of a diploma-thesis for the degree graduate physicist.

---

The author wishes to express his sincere gratitude to Professor V. Votruba and Dr. L. Valenta for suggesting this work and for many helpful discussions and criticisms.     

Casimir operators for infinite-dimensional representations ofosp(1,2) andosp(1, 4) lie superalgebras

All independent Casimir operatorsK _2j , 1 j n, are considered for the Schurean -dimensional representations ofosp(1, 2n),n= 1,2, that were constructed recently. For these representations (which are expressed in terms of tensor products of linear differential operators andN byN matrices belonging to a finite set and depending on a real parameter) a method is presented by which the differential-operator part of operators K_2j is effectively eliminated and expressions for K_2j via matrices in are obtained. In the same way we treat the Casimir operators _2j of the even subalgebra sp(2n, ) osp(1, 2n). The eigenvalues of K_2j and _2j are evaluated as functions of the parameter for the representations of osp(1, 2) withN= 2 and ofosp(1, 4) withN = 2, 4.     

Stationary non-equilibrium states of infinite harmonic systems

We investigate the existence, properties and approach to stationary non-equilibrium states of infinite harmonic crystals. For classical systems these stationary states are, like the Gibbs states, Gaussian measures on the phase space of the infinite system (analogues results are true for quantum systems). Their ergodic properties are the same as those of the equilibrium states: e.g. for ordered periodic crystals they are Bernoulli. Unlike the equilibrium states however they are not stable towards perturbations in the potential.We are particularly concerned here with states in which there is a non-vanishing steady heat flux passing through every point of the infinite system. Such superheat-conducting states are of course only possible in systems in which Fourier's law does not hold: the perfect harmonic crystal being an example of such a system. For a one dimensional system, we find such states (explicitely) as limits, whent, of time evolved initial states _i in which the left and right parts of the infinite crystal are in equilibrium at different temperatures, _L ^–L _R ^–1 , and the middle part is in an arbitrary state. We also investigate the limit of these stationary (t) states as the coupling strength between the system and the reservoirs goes to zero. In this limit we obtain a product state, where the reservoirs are in equilibrium at temperatures _L ^–1 and _R ^–1 and the system is in the unique stationary state of the reduced dynamics in the weak coupling limit.On leave of absence from the Fachbereich Physik der Universität München. Work supported by a Max Kade Foundation FellowshipResearch supported in part by NSF Grant MPS75-20638     

High-temperature resistivity of Ti1-X Al X alloys

We have measured the high-temperature resistivities of dilute Ti_1-x Al _x alloys withx0.135 up to 1100 K (2.6 _D , where _D is the Debye temperature). We observe that possesses a strong downward deviation from a linear temperature-dependence at high temperatures (several hundred degrees Kelvin). Eventually, saturates to a constant. This non-Bloch-Grüneisen-like behavior is compared with the predictions of current theories.     

Zur Sichtbarmachung von Reptation-Erscheinungen an Rahmeneinkristallen

Zusammenfassung An einem Rahmeneinkristall wurde mit Hilfe der Kolloidmethode die Bewegung von BlochwÄnden infolge wiederholten Ein- und Ausschaltens eines konstanten FeldesH _A im Mikroskop beobachtet. Es zeigte sich, da\ es sich um Reptation-Erscheinungen im Sinne von Néel handelt. Diese mikroskopischen Reptation-Erscheinungen konnten nur in unmittelbarer NÄhe von Löchern im Kristall beobachtet werden, bei denen die Grundbereiche durch das wiederholte Ein- und Ausschalten des FeldesH _A geÄndert wurden.

---

H _A . , . , H _A .

---

---

Für die wertvolle Hilfe bei der Herstellung des Rahmeneinkristalls und der Me\-anordnung möchten wir an dieser Stelle besonders Herrn W. Schwab danken.     

ДЕФОКУСИРОВКА ДИФФР АКТОМЕТРА ШУЛЬЦА

, .     

On the magnetic susceptibility of Pd1−x Ag x in the range 0.5≦x≦1

The weak variation of the magnetic bulk susceptibility of Pd_1–x Ag _x with temperature T and silver mole fractionx within 0.5x1 has been investigated in the range 5KT400K. Experimental evidence can be given for an intersection point of the susceptibility isotherms (T=const,x) atx=0.55. The observed dependence of on T andx is interpreted by means of a semiphenomenological alloy susceptibility function (T,x).     

Die Integralbeziehungen bei der stationären laminaren Strömung mit geschlossenen Stromlinien in annähernd kreisförmigen Gebieten

Zusammenfassung Für die statioäre lineare ebene Strömung mit geschlossenen Stromlinien bei einer großen Reynoldsschen Zahl in annähernd kreisförmigen Gebieten werden zwei Integralbeziehungen (5) und (9) abgeleitet. Nach der ersten von diesen ist das Integral der Reibungskraft entlang der Grenze des Strömungsgebiets direkt proportional der Länge dieser Grenze und der Größe der Rotation der Geschwindigkeit im Kern der Strömung. Aus der zweiten Beziehung geht hervor: Das Volumen der in der Zeiteinheit den Schnitt der Rezirkulationsgrenzschicht durchfließenden Flüssigkeit ist direkt proportional dem Integral entlang der Gebietsgrenze aus der Differenz der Quadrate der Strömungsgeschwindigkeit an der Grenze des Kerns und der Geschwindigkeit an der Gebietsgrenze und umgekehrt proportional der Größe der Geschwindigkeitsrotation im Kern und der Länge der Gebietsgrenze.

---

(5) (9). . : , , .

     

Релятивистские волн овые уравнения ддя ча стиц со спином 3/2

3/2.     

СПЕКТРАЛЬНЫЙ СОСТАВ И ИНТЕНСИВНОСТЬ ЛЮМИНЕСЦЕНТНОГО СВЕ ЧЕНИЯ ФОТОГРАФИЧЕСК ОЙ ЭМУЛЬСИИ

- - .     

Determination of parameters in equation for ferromagnetic resonance of ferrites

The paper describes a new method for determining the parameters in the equation for ferromagnetic resonance — the internal effective field, the spectroscopic splitting factor and the saturation magnetization in polycrystalline magnetically isotropic ferrites. Relations are derived for calculating these parameters by means of the values of the resonance external static fields, which are obtained by measuring on samples having different geometrical shapes and differently arranged static and microwave magnetic fields. The advantages and disadvantages of the method and remarks on the experimental method are given. The paper ends with an example of measurement.

---

: , . , . . .

---

---

The determination of the saturation magnetization of ferrites by the method described here was reported on at the Seminary on Ferrites in Microwave Technique, held by the Institute of Technical Physics, Czechoslovak Academy of Sciences, and the Research Institute of Communications Engineering of A. S. Popov, on November 25, 1959.     

ЛЮМИНЕСЦЕНЦИЯ КРИСТ АЛЛОВ AgCl

AgCl –180°. . , ( : =4640 Å, =5080 Å). , , . . - . –183°, =1,6. 10^–8%±10%.

---

Luminescence of AgCl crystals

The luminescence of normal and deformed single crystals of AgCl of different thickness was measured at a temperature of –180°C. With deformed samples the decrease in intensity of the luminescence was measured. On the luminescence band of the above crystals we observed a fine structure for which the series rule could be used (edge of series =4640 Å, =5080 Å).The observed luminescence was explained by means of the exciton mechanism proposed by Matyá, i.e. annihilation of a localized exciton either on a cation vacancy or on a cation vacancy on a dislocation jog. The luminescence yield at –183°C, =1.6×10^–3%±10%, was measured by a photographic method.

     

Long-range order in the XXZ model

The existence of long-range order is proved under certain conditions for the antiferromagnetic quantum spin system with anisotropic interactions (XXZ model) on the simple cubic or the square lattice. In three dimensions (the simple cubic lattice), finite long-range order exists at sufficiently low temperatures for any anisotropy(0) ifS1, and for 0<0.29 (XY-like) or>1.19 (Ising-like) ifS=1/2. In two dimensions (the square lattice), ground-state long-range order exists under the following conditions: for any anisotropy (0) ifS3/2; 0<0.032 (XY-like) or 0.67<<1.34 (almost isotropic) or>1.80 (Ising-like) ifS=1;>1.93 (Ising-like) ifS=1/2. We conjecture that the two-dimensional spin-1/2XY model (=0) has finite ground-state long-range order. Numerical evidence supporting this conjecture is given.