Characteristics analysis of metal-clad and absorptive dielectric waveguides by a simple and accurate perturbation method

We present a simple and accurate method for characteristic analysis of metal-clad dielectric waveguides and absorptive waveguides. The real partN of the complex modal indexN=N + iN is obtained by solving the corresponding real eigenvalue equation, and the imaginary partN is given by (n/), where= + i is the complex dielectric constant of the absorptive layer, and N/ is obtained by numerical differentiation. The method is straightforward, and the cumbersome solution of complex transcendental equations is completely eliminated. Results for simple structures are in good agreement with those obtained by exact analysis.     

Correlations of Spin States for Icosahedral Double Group

The irreducible bases of the icosahedral double groups I and I_h are explicitly presented in their respective group spaces. Applying these bases to the spin states |j, , we obtain a simple formula for combining the spin states into the symmetry-adapted bases which belong to a given row of given irreducible representations of I and I_h.     

Novel perturbation expansion for the Langevin equation

We discuss the randomly driven systemdx/dt= -W(x) +f(t), wheref(t) is a Gaussian random function or stirring force withf(t)f(t)=2(t–t), andW(x) is of the formgx ¹⁺². The parameter is a measure of the nonlinearity of the equation. We show how to obtain the correlation functionsx(t)f(t)···x(t( n)) _f as a power series in. We obtain three terms in the expansion and show how to use Padé approximants to analytically continue the answer in the variable. By using scaling relations, we show how to get a uniform approximation to the equal-time correlation functions valid for allg and.     

Влияние переменного магнитного поля на остаточное состоя ние магнитно — Мягких материалов

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The influence of an alternating magnetic field on the remanent state of magnetically soft materials

A study is made of the influence of an alternating magnetic field of varying maximum amplitude on the remanent state, or rather, apparent remanent state of toroidal and open samples of metallic and non-metallic magnetically soft ferromagnetics. An interpretation of the corresponding dependences is given on the basis of Kondorski's conception of the composition of a polycrystalline jerromagnetic material.

     

Kinetic theory of adsorption and desorption

In this paper we use stochastic methods to discuss adsorption and desorption. The paper derives generalized coefficients of sticking and accomodation depending on surface temperatureT _s and gas temperatureT _g and shows, that for additive Markov processes, these kinetic coefficients are identical. Furthermore, exact solutions of the kinetic equations for certain simple transition probabilitiesP(, ) are found and an approximation method for more complicatedP(, ) is given. The comparison of the theory with experimental results for noble gas-metal systems indicate a quadratic relationship between the first moment of the transition probabilityP(, ) and the well depth of the physisorption system.     

Symmetries and half-sided modular inclusions of von Neumann algebras

LetN, be a von Neumann algebras on a Hilbert space , a common cyclic and separating vector. Assume to be cyclic and also separating forN . Denote by , _N , _N the modular operators to (, ), (N, ), resp (N , ). Assume now ^-it N ^it N for allt 0. (Such type of inclusions ((N U, ) , ) are called half-sided modular.) Then the modular groups ^it , _N ^ir , _N ^is ,t, r, s generate a unitary representation of the group S1(2, )/Z ₂ of positive energy.Another result is related to two half-sided modular inclusions (₁ , ) and (₂ , ). Under proper conditions the three modular groups ^it , ₁ ^ir , ₂ ^is ,t, r, s generate the three-dimensional subgroup of O(2, 1) of two commuting translations and the Lorentz transformation.Partly supported by the DFG, SFB 288 Differentialgeometrie und Quantenphysik.     

Bunching phenomena during electron injection into the betatron II. Theory of starting conditions

A theory of the azimuthal bunching of electrons injected into the betatron is presented and compared with the experiments described in [1]. The bunching is treated as a small perturbation of the stationary beam.The stationary injected beam is replaced by the corresponding equilibrium beam of the same perveance so that the angular velocity spread of the injected electrons is proportional to the square root of the injection perveance.Self-consistent wave solutions for the perturbation of the stationary solution are then found. Equations giving the amplification of small density or energy disturbances along the beam are derived. These disturbances are assumed to be introduced by density or velocity modulation of the injected beam. The condition for the spontaneous occurrence of bunching is deduced by assuming that the disturbances do not vanish even when there is no modulation of the injected beam. The resulting expressions for the threshold perveance and the rise-time of the disturbance are in reasonably good agreement with the experiments. Such agreement may be considered as further verification of the statement made in [1] that the amplification of the disturbances is caused by the negative mass instability mechanism.

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Small perturbations ofC*-dynamical systems

It is shown that if is the generator of a strongly continuous oneparameter group of *-automorphisms of aC*-algebraA and is an unbounded *-derivation ofA with the same domain as , then + is also a generator for all sufficiently small real numbers .     

An interpretation of the conditions for the existence of Shockley surface states

A study is made of the Shockley surface states in a linear chain of equal atoms, joined by alternately strong bonds. If the simple MO LCAO method is used, which considers the exchange integrals between nearest neighbours and next nearest neighbours, we get the surface states for a semi-infinite chain if the stronger bond is interrupted. The connection between Shockley and Tamm surface states is shown and the hypothesis is put forward that the condition for the existence of Shockley surface states has a generally simple physical interpretation, the validity of which is proved on the models of a semi-infinite crystal studied up to now.

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Temperature Dependence of the Gibbs State in the Random Energy Model

We consider the problem of temperature dependence of the Gibbs states in two spin-glass models: Derrida's Random Energy Model and its analogue, where the random variables in the Hamiltonian are replaced by independent standard Brownian motions. For both of them we compute in the thermodynamic limit the overlap distribution ^N _{i=1 i i} /N[–1,1] of two spin configurations , under the product of two Gibbs measures, which are taken at temperatures T,T respectively. If TT are fixed, then at low temperature phase the results are different for these models: for the first one this distribution is D _{0 0}+D _{1 1}, with random weights D ₀, D ₁, while for the second one it is ₀. We compute consequently the overlap distribution for the second model whenever T–T0 at different speeds as N.     

Mixed-valence states in TCNQ salts of monoalkylbiferrocenes and their mixed crystals with dialkyl derivative

TCNQ salts of 1-monoalkylbiferrocenes showed a temperature-independent trapped-valence state as expected for the unsymmetrical structure of cations. On the other hand, mixed crystals of 1-monobutyl- and 1.1-dibutylbiferrocenium⁺(TCNQ) ₃ ^– showed a temperature dependence of the mixed-valence states, showing that the lattice affects the mixed-valence states.     

S0-S1 two photon absorption dynamics of organic dye solutions

The two-photon absorption cross-sections and excited-state absorption cross-sections of the dyes rhodamine 6G, methylene blue and fuchsin dissolved in methanol, and of the dyes safranine T, 1,3,3,1,3,3-hexamethylindocarbocyanine iodide (HMICI) and 1,3,1,3-tetramethyl-2,2-dioxopyrimidi-6,6-carbocyanine hydrogen sulphate (PYC) dissolved in hexafluoroisopropanol (HFIP) are determined. The excitation is achieved with picosecond light pulses of a passively mode-locked Nd-glass laser (_L = 1.054m). The influence of amplified spontaneous emission on the two-photon absorption dynamics is analysed.     

Monte Carlo study of the surface area of liquid droplets

Computer simulation of droplets containingl molecules (l 1000) in a lattice gas shows that the average surface area is proportional tol ; 0.6 in two and = 0.825 in three dimensions for small droplets. These exponents agree approximately with those in Kadanoff's modification of Fisher's droplet model near critical points [= (1 + )/; ourT/T _c is 0.4, 0.7, and 0.9]. For larger droplets, these exponents change to 1/2 (d = 2) and 2/3 (d = 3), the transition occurring for droplet diameters larger than the coherence length and smaller than the critical diameter in the nucleation of supersaturated vapors. This latter result rises some doubts on a recent nucleation theory of Eggingtonet al.     

ВОЗМОЖНОСТЬ ИССЛЕДО ВАНИЯ ХОДА ИСКАЖЕНИЙ РЕШЕТКИ В КРИСТАЛЛИКАХ ПРИ ПО МОЩИ РЕНТГЕНОВСКИХ Л УЧЕЙ РАЗНОЙ ДЛИНЫ ВОЛНЫ

, . , (K , , ), - , -. -, 25 a 1956.     

On the problem of a cyclotron for particles with relativistic increase in mass

The paper deals with the problem of circular accelerators with time constant magnetic field and constant frequency of the accelerating voltage. An analysis is made of the possibility of compensating the change in time of revolution (caused by the increase in mass during energy growth) by simultaneous axial and radial displacement of the equilibrium orbit. It is found that the problem can be solved only with certain approximations. The approximate numerical parameters of the accelerator are given and the approximations used are discussed. The paper is based on [1].

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In conclusion the author thanks the director of the institute Ing. J. Váa for permitting publication and Dr. M. Seidl, Ing. J. Teichman, Ing. R. Klíma and Ing. Z. Sedláek who, apart from solving other problems of the accelerator, cooperated with the author on its very conception.     

ИспОльжОВАНИЕ ФлУОР ЕсцЕНтНОгО РЕНтгЕНО ВскОгО ИжлУЧЕНИь Дль кОНтАк тНОИ МИкРОРАДИОгРАФ ИИ

( )K- Fe, Ti Ca . , , , . , , , K- , .

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The use of fluorescent X-rays for contact microradiography

The possibilities of using fluorescentK-radiation of the elements Fe, Ti and Ca for contact microradiography of thin, little absorbing samples were studied and a simple set-up for carrying out this method, which uses a common type of microstructural X-ray tube as a source of the exciting radiation, was proposed. The experiments performed showed that if large magnifications are not required secondary-excitedK-radiation of the above-mentioned elements can be advantageously used for contact microradiography without the exposure times becoming impracticably long.

     

Dielectric constant characterization of large-area substrates in millimeter wave band

A possibility of the dielectric constant measurement for substrates with permittivity=+i without an essential restriction on their area has been shown experimentally. The method uses frequency measurement of quasioptical dielectric resonator (QDR) with two slots oriented along the QDR radius with a dielectric substrate in one of them. Taking QDR of teflon in 8mm waveband as an example it is found that measurable values of can ran up 15 _q , where _q is the QDR material permittivity. Absolute error of the measurements is determined by an accuracy with which the permittivity of calibrated (standard) samples is known. The relative measuring error is determined by the accuracy of the QDR frequency measurement and can be quite a small. As an example the method is demonstrated forLaAlO ₃ single crystals.     

Efficient White Light Emitting Using an Electron Blocker in Non-Doped Type Organic Electroluminescent Devices

Non-doped type white organic electroluminescent (EL) devices using vacuum-deposited organic thin films of blue-emitting 4,4-bis(2,2 diphenylvinyl)-1,1-biphenyl (DPVBi) and yellow-emitting ultrathin 5,6,11,12-tetraphenylnaphthacene (rubrene) to generate white emission were fabricated. The two emitting layers are separated by an electron blocking layer of N,N-bis-(1-naphthyl)-N,N-diphenyl-1,1-biph-enyl-4,4-diamine (NPB). The thickness of the blocking layer determines the spectrum of the devices. In a device with 5 nm electron blocker of NPB, the CIE coordinates were well within the white region for voltage raging from 3 V to 14 V. The device has a maximum luminance of 7400 cd/m²(at current density of 830 mA/cm²) and maximum power efficiency of 1.67 lm/W at 5 V.     

Chelate complexes of gold(III)

New gold(III) complexes involving substituted picolinic acids acting as bidentate ligands have been characterised: [AuCl₂(LL), and [Au(LL)₂]⁺ (H-LL=hydroxy- or carboxy-substituted picolinic acid). The latter readily undergo deprotonation of the substituent on one ligand, to yield novel uncharged complexes which appear to be polymeric via hydrogen bonds between protonated and depronated substituents. A completely depronated anionic complex has also been obtained. The characterisation of these materials was considerably aided by¹⁹⁷Au Mussbauer spectroscopy.     

Transquantum Dynamics

Segal proposed transquantum commutation relations with two transquantum constants , besides Planck's quantum constant and with a variable i. The Heisenberg quantum algebra is a contraction—in a more general sense than that of Inönü and Wigner—of the Segal transquantum algebra. The usual constant i arises as a vacuum order-parameter in the quantum limit ,0. One physical consequence is a discrete spectrum for canonical variables and space-time coordinates. Another is an interconversion of time and energy accompanying space-time meltdown (disorder), with a fundamental conversion factor of some kilograms of energy per second.