bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spektrale Intensitätsverteilung der Compton‐Strahlung nach dem Thomas‐Fermi‐Modell
Authors: Weick Dietrich 
Published: May 2007

AbstractIt is shown, that the results obtained by Heisenberg [11] and Bewilogua [12] for the total intensity of incoherent scattering of x‐rays (at a fixed scattering angle) on the basis of the Thomas‐Fermi‐model contain information also with respect to the spectral distribution of the scattered radiation.A remarkable consequence is an asymmetry of the Compton‐line‐profile, which is increasing with the influence of electronic binding.This gives rise to some modifications of current views concerning
the application of the Breit‐Dirac correction factor to the Waller‐Hartree‐formula (§ 3), and
the connexion between the Compton‐line‐profile and the electron‐momentum‐density‐distribution (§ 4).
Untersuchung des Einflusses von Zusatzelementen zu hochreinem Kupfer auf die Eigenschaften von Cu2O‐Gleichrichtern
Authors: Brodowsky Ulrich , Häussler Günter 
Published: May 2007

AbstractDurch gezielte Dotierung von hochreinem Kupfer können die Kennlinienparameter der daraus hergestellten Kupferoxydul‐Gleichrichter in einem großen Bereich reproduzierbar variiert werden. Um technisch brauchbare Gleichrichter zu erhalten, ist eine Dotierung mit mindestens zwei spezifisch wirksamen Elementen erforderlich.
E‐H‐Zyklotronechos in Plasmen
Authors: Bachmann P. , Sauer K. , Wallis G. 
Published: May 2007

A new echo type with free electrons in a slight inhomogeneous magnetic field excited by one electric and one magnetic pulse is calculated. Thus features of cyclotron echos and spin echoes are combined. The first electric pulse accelerates all (cold) particles to the same velocity as in the case of usual cyclotron echoes. The second magnetic pulse (at t = τ) rotates the plane of precession in phase space, quite in analogy to the motion of magnetic moments in the case of spin echoes. The echo arises at t = 2τ.The E‐H echoes make relaxation and diffusion measurements in plasmas possible, using the methods proved useful in spin echo technique. There are no complications as in the case of E‐E cyclotron echoes which are based on the fact that a velocity‐dependent collision frequency is necessary for the nonlinearity of that echo mechanism.
Untersuchungen zur Feldelektronenmission aus Germaniumeinkristallflächen
Authors: Zuther G. , Köster H. , Becherer G. 
Published: May 2007

AbstractMit Hilfe der “probe‐hole”‐Technik wurden die Strom‐Spannungs‐Kennlinin der Feldemission aus Germaniumeinkristallflächen gemessen. Es wird über Ergebnisse berichtet, die an durch Felddesorption gereinigten und an geglühten Germaniumemitern erhalten wurden. Aus der Steigung der Strom‐Spannungs‐Kennlinien können die Austrittsarbeitsdifferenzen der einzelnen Einkristallflächen ermittelt werden.
Theory of the lonization Equilibrium in Dense Plasmas
Authors: Ebeling W. , Sändig R. 
Published: May 2007

AbstractThe SAHA equation for the ionization equilibrium in plasmas is analyzed. Especially the balance between the effect of bound states (mass action constant) and the effect of free states (lowering of the ionization energy) is investigated.The lowering of the ionization energy is represented as an expansion with respect to the density. It is shown that the coefficients of this expansion and the mass action constant are connected with the known quantum statistical virial coefficients. The question of introducing the energy levels of a screened COULOMB potential is investigated. Several possibilities for the choice of the weight factor in the mass action constant are discussed. In the case of higher densities PADÉ approximations for the ionization energy are constructed. The existence of instabilities of the NORMAN‐STAROSTIN‐type is discussed.
On the Treatment of Thermo‐Electrodynamical Processes by GYARMATI's Principle
Authors: Vincze Gy. 
Published: May 2007

AbstractIn this paper the GYARMATI's governing principle of dissipative processes is applied to a continuous material system with reversible polarization, magnetization and irreversible electric conduction phenomena due to finite electrical conductivity. After the general treatment of governing principle and MAXWELL's field equations the forms of the balances of internal energy and entropy are determined. The main new results are the recovering of the electromagnetic field equations from the actual form of the governing principle and the verification of gauge invariance property of it.
A Purely Geometrical Introduction of Spinors in Special Relativity by Means of Conformal Mappings on the Celestial Sphere
Authors: Ebner D. W. 
Published: May 2007

AbstractSpinors are introduced using geometrical concepts only, such that no knowledge in representation theory is presupposed. The essential part is the purely geometrical proof of the conformity of the mapping of the celestial sphere onto itself induced by spinors.
Berechnung der Zustandsdichte und der Röntgen‐K‐Emissionsbanden in GaAs
Authors: Topol I. , Hess E. 
Published: May 2007

AbstractThe density of states and the X‐ray K‐emission bands of GaAs have been calculated by a combination of the empirical pseudopotential‐ und k · p‐method, whereby broadening effects due to the width of the inner K states and to finite spectral resolution have been considered. The dependence of the transition probability on k for the various bands is evaluated explicitly. The agreement with experimental data is very good.
Schwere Photonen in der klassischen Elektrodynamik
Authors: Treder H.‐J. 
Published: May 2007

AbstractThe corresponding classical electrodynamics to a quantum electrodynamics with a propagator depending on restmassless photons and photons with restmass, too, is a field theory of the fourth order given by the wave‐operator □ (1− □/k2). This electrodynamics has a physical meaning only if the electro‐static potential ϕ becomes the COULOMB potential asymptotically, and if the point‐like field sources (electrons) have monopol‐like chargedistributions: ϱ ∼ δ(r). From these postulates results that such a classical field‐theory becomes the electrodynamics of BOPP and of PODOLSKY. However, such a classical electrodynamics is only possible with time‐like photons, the hypothesis of space‐like photons gives contradictions to the postulates about the electro‐static field and about the monopol‐like structure of the point‐like electron‐charges.
Zur Kenntnis deo Röntgen‐LIII‐Abrorptionsspektrumo der Platins
Authors: Keilacker H. , Meisel A. 
Published: May 2007

AbstractBy the LIII absorption spectrum of platinum it is demonstrated the possibility to obtain correct X‐ray absorption spectra also with regard to the intensities of the fine structures, using a focussing X‐ray spectrometer and proportional counter.
Approximation Methods for the Solution of Heat Conduction Problems Using Gyarmati's Principle
Authors: Stark A. 
Published: May 2007

AbstractAfter a brief description of GYARMATI's Governing Principle of Dissipative Processes, general approximation methods are developed for heat conduction phenomena on two scales. On the first scale the temperature and heat current density fields are approximated by two different sets of functions in such a way that the internal energy balance and the imposed boundary conditions be satisfied. On the second scale we introduce a new temperature field related to the heat current density through the constitutive equation. Since the dissipation potentials in GYARMATI's principle are connected with each other by LEGENDRE dual transformations we call “dual field methods” the approximation procedure based on the two temperature fields. It is shown that the equations of the GALERKIN method, the method of orthogonal projections, and the TREFFTZ method, when applied to the appropriate problems, are included in the approximation schemes. Due to their great importance a special paragraph is devoted to the treatment of eigenvalue problems. Finally, the approximation methods are illustrated by a simple example and the results are compared with the exact solution.
Theorie der parametrischen Vier‐Photonen‐Wechselwirkung. III. Verstärkung und Oszillation bei Berücksichtigung der Rückwirkung auf die Pumpwelle
Authors: Frahm Jürgen , Fischer Randolf 
Published: May 2007

AbstractThe processes of parametric amplification and oscillation in a medium with cubic polarization are investigated theoretically taking into consideration the depletion of the pump wave. We suppose that phase‐matching is realized exactly (a possible nonlinear detuning of the exact phase‐matching should be compensated by a suitable subsequent adjustment of the frequencies). A consequence of linear losses is the appearance of a threshold for the parametric amplification. There exist a maximum length, a minimum length and an optimum length of the nonlinear medium for the process of parametric amplification.The threshold intensity, the optimum length of the nonlinear medium and the optimum reflection coefficient for outcoupling are determined for two arrangements of the double resonant parametric four‐photon oscillator (ring resonator, FABRY‐PEROT resonator). It is shown that for the above mentioned arrangements of the single resonant and the double resonant four‐photon oscillator the efficiency is a monotonous function of the threshold excess. On the contrary in case of the three‐photon oscillator there exists an optimum value of the threshold excess.
Temperature‐ and Concentration‐Dependence of the Spin‐Lattice Relaxation Time of Chromium Ions in GASH
Authors: Kirmse R. , Solovev B. V. , Sakharov V. A. , Tarasov B. G. 
Published: May 2007

AbstractInvestigations of the temperature‐ and concentration dependence of the spin‐lattice relaxation time T1 in ferroelectric GASH (= Guanidinium aluminium sulfate hexahydrate) single crystals doped with Cr3+‐ions are reported. The concentration‐dependence found on the higher concentrated crystals C 0.1% Cr3+) as well as the observed cross‐relaxation are explained in terms of spin‐lattice relaxation via exchange pairs. Using the VAN VLECK formalism T1 has been estimated for Cr3+: GASH by comparision of the present system and K‐Cr‐alum.
Pion PT Distribution and a Test of Scaling Hypothesis at an Incident Proton Energy of 24 GeV
Authors: Daftari I. K. , Bandyopadhyay B. K. , Roy T. 
Published: May 2007

AbstractThe transverse momentum distribution of 900 secondary pions produced in interactions of 24 GeV protons with emulsion nuclei is seen to agree fairly well with the HAGEDORN distribution for a' = 3/2 and b' adjusted to 133 MeV. A satisfactory fit of FEYNMANS scaling idea is also observed at this incident energy.
Berechnung der Aufbauzeit eines doppeltresonanten optischen parametrischen Oszillators
Authors: Brunner W. , Fischer R. , Paul H. 
Published: May 2007

AbstractThe rise time for the output power of a doubly resonant optical parametric oscillator with ring resonator configuration is calculated for the special case of subharmonic generation. It is shown that the rise time decreases by increasing the pumping level (for a constant threshold power) and, for a constant pumping level, by increasing the resonator loss.
Elektronen‐Spin‐Gitter‐ und Spin‐Spin‐Relaxation von Cu(II) in Ni(II)‐bis(1,1‐dicyanoäthylen‐2,2‐dithiolat)‐Einkristallen
Authors: Kirmse R. , Solovev B. V. , Tarasov B. G. 
Published: May 2007

AbstractEs wird über die Temperaturabhängigkeit der Elektronen‐Spin‐Gitter‐ und ‐Spin‐Spin‐Relaxationszeiten T1 und T2 von Cu(II) in (Tetrabutylammonium)‐Ni(II)bis(1,1‐dicyanoäthylen‐2,2‐dithiolat)‐Einkristallen berichtet. Im Bereich der direkten Relaxationsprozesse (2…7°K) wird eine Abhängigkeit der Spin‐Gitter‐Relaxationsgeschwindigkeit von der Projektion des Cu‐Kernspins beobachtet. Über die Temperaturabhängigkeit des RAMAN‐Prozesses wird die DEBYE‐Temperatur des Molekülkristalles zu θ = (100 ± 10)°K sowie die mittlere Schallgeschwindigkeit 〈v〉 ≈ 0,7. 105 cm/sec abgeleitet. Zur Aufklärung der im gesamten untersuchten Temperaturbereich von 2,0…300°K ungewöhnlich geringen Linienbreite der 63,65Cu‐Hyperfeinstrukturlinien des EPR‐Spektrums werden die Beiträge der zur Linienbreite beitragenden Mechanismen analysiert. Es werden Betrachtungen zum möglichen Einfluß der starken Kovalenz der Cu‐Ligand‐Bindungen auf T1 durchgeführt.
One‐Particle Distribution Functions and Thermodynamics of Crystals with Many‐Body Forces. II. Quantum Corrections
Authors: Zubov V. I. 
Published: May 2007

AbstractCrystalline state is described by non‐symmetrical distribution functions in a self‐consistent field approximation. The first quantum corrections to the HELMHOLTZ free energy and thermodynamic properties of strongly anharmonic crystals with many‐body interactions are calculated in the quasi‐classical case. The properties of crystalline inert gases are computed using the pair potentials of LENNARD‐JONES, of BARKER and POMPE, of BARKER and BOBETIC, and of BARKER, FISHER and WATTS, together with the AXILROD‐TELLER‐MUTO three‐body forces. The results are compared with both the experimental data and Monte Carlo calculations.
Neutrino‐Pair Bremsstrahlung from a Hot Plasma in the Presence of a Strong Magnetic Field
Authors: El‐Kheshin M. , Allam S. H. , Phillips A. H. 
Published: May 2007

AbstractThe stellar energy loss rate due to the production of neutrino pairs by Bremsstrahlung is calculated for neutron stars in the presence of a strong magnetic field (B ⩽ 1012 G) and the Coulomb field of the positive ions. The calculated energy loss rates are applied to nonrelativistic electrons at low densities ⩽ 105 gm/cm3 and relatively low temperatures T ⩽ 109 K.
A Different Approach to the Multiplicity Problem in Hadron Collisions
Authors: Ghosh D. C. , Roychowdhury A. , Daftari I. K. , Bhattacharjee D. K. , Roy T. 
Published: May 2007

AbstractThe models frequently applied to estimate the target mass in high energy interactions are used in conjunction with the HEISENBERG formula to obtain a semi empirical formulation for multiplicity.It is seen that the experimental data obtained by us and other authors on multiplicity fit into that formulation when considering the initial colliding systems to be either π ‐ p or π ‐ π. Also the values of Cos θ (θ being the emission angle of the secondaries in lab system) averaged over all emitted particles estimated from the above formulation are in good agreement with our experimental data.
Proton‐Proton Interaction in a Dual Model
Authors: Bugrij A. I. , Chikovani Z. E. , Kobylinsky N. A. 
Published: May 2007

AbstractThe “background‐pomeron” component of the amplitude is studied in the framework of a dual model with square‐root trajectories. Double pomeron poles are used as vacuum exchanges in various channels, with exotic Regge poles dual to them. The expressions obtained are applied to describe total and differential cross sections of proton‐proton interaction in wid eenergy regions.
Quantum Theory of Localized Crystal
Authors: Yukalov V. I. 
Published: May 2007

AbstractA quantum crystal each particle of which is located to a proximity of one lattice point is considered. The causal Green functions at finite temperatures are used. The localized approximation for the iteration of propagator equations is formulated. New type conditions defining parameters of model propagator are proposed. The general method is illustrated with the example of a linear chain.
Bifurcations in a Bistable Reaction‐Diffusion System
Authors: Ebeling Werner , Malchow Horst 
Published: May 2007

AbstractThe bifurcations of stationary solutions of bistable reaction‐diffusion systems and especially the model due to Schlögl are investigated. The paper is based on the observation that these dynamical systems belong to the gradient type, i.e. methods of topological investigation of the corresponding potential may be applied. Three different types of models are discussed: 1. Homogeneous model; 2. Compartmental model with diffusion; 3. Continuous model with diffusion. Bifurcation maps and relations to catastrophe theory are given.
Secondary Neutral Pion‐nucleon Flux Ratio at the Top of the Atmosphere
Authors: Roychoudhury R. K. , Bhattacharyya D. P. 
Published: May 2007

AbstractThe CERN Intersecting Storage Ring data on the inclusive reaction p + p → π° + X has been fitted with a phenomenological form

where Wc(a,b,z) is the generalized confluent function defined by

.M(a, b, z) being the well known Kummer's function. Using this form and primary proton spectrum of Goddard Space Flight Center Group the secondary neutral pion‐nucleon flux ratio at the top of the atmosphere has been estimated. The derived result has been compared with those expected from p + p → π± + X data, via different models.
Theory of Gravitational‐Inertial Field of Universe. III. The Structure of Critical Systems
Authors: Davtyan O. K. 
Published: May 2007

AbstractApplication of gravitational‐inertial field equations to all critical systems, including the Universe, results in conclusion that Hubble's law represents a general law for all critical systems. According to it, inside the critical systems in the absence (or under neglection) of local fields, each material point serves as a center of “dispersion” of bodies.Because of this principle and because of the phenomenon of gravitational and inertial annihilation of mass, all the mass becomes concentrated with time on a surface of horizon of events in form of electromagnetic‐gravitational radiation‐the geon mass. It means that critical systems are actually geon crowns.On basis of these results a conclusion is also made that the quasistellar objects should be just such kind of objects which are in a zone of intensive “combustion” of mass.
Theory of Gravitational‐Inertial Field of Universe. IV. The Universe and the Microcosm
Authors: Davtyan O. K. 
Published: May 2007

AbstractOn basis of principle of discreteness of the space and time the following relations are obtained ΛoMoc = 2πℏ, τoEo = 2πℏ and c2 = 2GMo/Λo giving the values of fundamental elements of length Λo ≈ (ℏG/c3)1/2, mass Mo ≈ (ℏc/G)1/2, time τo ≈ (ℏG/c5)1/2 and energy Eo ≈ (ℏc5/G)1/2.The geon crown of any critical system and the crown of the Universe must have a thickness equal to the fundamental length Λo = 2(πℏG/c3)1/2 = 5.74. 10−33 cm.Each critical system has its specific (most probable) quantum with an average invariant mass which in the case of the Universe is equal to (2π2ℏHu/Gc)1/3 ≈ 300 me where Hu is Hubble's constant.There are all reasons to consider the universal virtual quanta of an invariant mass mu ≈ 300 me as carriers of gravitational, electromagnetic and nuclear fields in the Universe.
Liouville Equation for Turbulent Gases
Authors: Wilhelm H. E. 
Published: May 2007

AbstractThe Hamiltonian H and Hamilton equations of motion are derived for the Fourier amplitudes pk and qk of the canonical conjugate fields p and q defined by p = mν and ∂q/∂t = nν where ν(r, t) and n(r, t) are the velocity and density fields of ideal, compressible gases in the state of fully developed turbulence. A Liouville equation is presented for the distribution function f(pk, qk; {k}) in the multidimensional phase space formed by the scalar components of the set {k} of wave mode vectors pk and qk. Though the theory is highly idealized since viscous and thermal dissipation are not taken into account, it may be considered as a first attempt at extending statistical mechanics to random continuous media.As an application, that stationary solution f = f(H) of the Liouville equation is calculated, which maximizes the turbulence entropy. It is shown that the distribution of the velocity and density fluctuations of compressible gases is Gaussian in fully developed turbulence, in agreement with the experiments.
Einsteins hermitesche Relativitätstheorie als Unifikation von Gravo‐ und Chromodynamik
Authors: Treder H.‐J. 
Published: May 2007

AbstractEinsteins „hermite‐symmetrische Fortsetzung der Allgemeinen Relativitätstheorie (ART) ins Komplexe„, seine hermitesche unitäre Feldtheorie, wurde von ihm als Unifizierung und Generalisierung der Einstein‐Maxwellschen Theorie, von Gravodynamik und Elektrodynamik, gedeutet. Jedoch führt — in der EIH‐Näherung — das n‐Teilchen‐Problem nicht zu Coulomb‐artigen Kräften zwischen den punktförmigen ”︁Ladungen„ ϱ— 4π ε δ(𝔯) (INFELD 1950), sondern vielmehr zu Kräften mit einem distanzunabhängigen Term (TREDER 1957):magnified imageDarüber hinaus zeigt die verallgemeinerte Schwarzschildsche Lösung (WYMAN 1950), daß es keine freie geladene Partikel geben kann: es gibt also kein freies Elektron.Demgegenüber haben die zur Modellierung der Quanten‐Chromo‐Dynamik als ”︁confinement„ für die Bewegungen der Quarks auftretenden Kräfte gerade die obige Form, und es gibt keine freien Quarks. – Daher wird vorgeschlagen, den rein imaginären antisymmmetrischen Teil gμv = –gvμ von Einsteins hermiteschem Fundamntal‐Tensor gμv = gv*μ als das Duale des ”︁Gluonenfeldes„ aufzufassen. Dann werden alle Eigentümlichkeiten der Einsteinschen Theorie physikalisch interpretierbar.Es gibt keine freien Quarks, denn die Feldmasse einer Farbladung divergiert wie —ε2γ; desgleichen divergieren die Feldmassen von Teilchen‐Systemen mit nichtverschwindender Gesamtladung \documentclass{article}\pagestyle{empty}\begin{document}$ \sum\limits_A^n {\varepsilon A} $\end{document} Beides ist ein Ergebnis des Gravitationsteils der Einsteinschen Gleichungen. Dagegen findet man als Integrations‐Bedingung für diese Gleichungen bei verschwindender Gesamtladung die obigen Kräfte 𝔉 A + B3· Kompensieren sich die Ladungen in einem Bereich∼L3, so findet man aus den Gravitationsgleichungen als asymptotische Masse M des n‐Teilchen‐Problems für r ≫ L einen mit der Ausdehnung des Systems wachsenden Wertmagnified image.
Einsteins Feldtheorie mit Fernparallelismus und Diracs Elektrodynamik. IV (Das Elektron als Wurmloch)
Authors: Kreisel Eckhard 
Published: May 2007

AbstractDie von H. Treder [1] und E. Kreisel [2, 4] untersuchte Feldtheorie von Gravitation und Elektromagnetismus liefert eine überall singularitätsfreie, statische, kugelsymmetrische Lösung, die ein Wurmlochmodell des Elektrons darstellt, wenn man die Kopplungskonstanten aus Treder [1] genügend stark abändert. Die Entwicklung von g00 nach Potenzen von 1/r enthält im Unterschied zur Reisner‐Nordström‐Lösung keinen Term proportional 1/r2. Die Ladung des Elektrons hat ihren Ursprung praktisch allein im Wurmloch; die gravo‐elektrisch induzierte Ladungsdichte ist trotz der großen Kopplungskonstante verschwindend gering.
Fugacity and Density Expansion for Systems with Bound States
Authors: Bartsch G. P. , Kremp D. 
Published: May 2007

AbstractThe fugacity expansion in different approximations for low densities and for systems with bound and scattering states is discussed. The meaning of a mixed expansion and the possibility to introduce a chemical picture for a system in which bound states dominate is proved. The possibility of a thermodynamical instability is shown.
Stochastic Theory of Nucleation in Nonequilibrium Bistable Reaction Systems
Authors: Schimansky‐Geier L. , Ebeling W. 
Published: May 2007

AbstractNucleation is one of the fundamental types of forming stable dissipative nonequilibrium structures in metastable initial states. The nucleation process of a bistable chemical reaction system is investigated. First a microdroplet with radius R0 of the new state imbedded in the parent one is formed by a local particle number fluctuation. The radius of the microdroplet R(t) fluctuates due to the interference of reaction and diffusion. If R(t) considerably exceeds a critical value Rk the droplet starts to grow deterministically. The mean nucleation time of one droplet in weakly supersaturated systems is calculated using the concept of the mean first passage time.
Influence of Coulomb Interactions on Dissipative Structures in Reaction‐Diffusion Systems
Authors: Ebeling W. , Feudel U. 
Published: May 2007

AbstractReaction‐Diffusion‐Systems with charged particles are considered. Conditions for the appearance of dissipative structures because of disturbances of an uniform initial stationary state in continuous and simple compartment systems are derived. As an example the appearance of a dissipative structure is demonstrated in a simple capacitor model. Based on this effect nonequilibrium electrical cells could be developed.