bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchung Iasererzeugter Plasmen für die Kernfusion
Authors: Basov N. G. , Sklizkov G. V. , Brunner W. , Junge K. 
Published: May 2007

AbstractNach einer kurzen Darstellung der Grundlagen der lasergesteuerten Kernfusion werden die theoretischen und experimentellen Ergebnisse vorgestellt und diskutiert, die an der Hochleistungslaseranlage „Delphin 1”︁ gewonnen wurden. Es wird gezeigt, daß Targetstrukturen mit großem Aspektverhältnis A = R/ΔR für die Laserfusion besonders geeignet erscheinen. Untersucht wird der Einfluß der Filamentierung auf das Kompressionsverhalten wie auch die Filamentierung selbst, wobei eine anomale Erzeugung der 2. Harmonischen der einfallenden Laserstrahlung in einen unterkritischen Dichtebereich des Plasmas experimentell nachgewiesen werden konnte.
Thermolumineszenz in Dosimetrie und Geowissenschaften
Authors: Herforth L. , Hübner K. , Stolz W. 
Published: May 2007

AbstractEs wird ein Überblick über neue Ergebnisse und Erfahrungen bei der Anwendung thermolumineszierender Stoffe in der Dosimetrie und in den Geowissenschaften gegeben.Schwerpunkte bilden die Bestimmung der Eigenschaften und Wechselwirkungsparameter von Speicherphosphoren sowie ihr Einsatz zur Dosimetrie in Neutronen‐Gamma‐Feldern. Ferner werden einige Möglichkeiten beschrieben, mit Hilfe der Thermolumineszenz das Alter von Sedimenten, vulkanischen Gesteinen und von Steinmeteoriten zu bestimmen sowie Minerale unterschiedlicher Genese zu charakterisieren.
Die Hypothesen der Erdexpansion im Lichte paläogeophysikalischer Ergebnisse
Authors: Lauterbach Robert 
Published: May 2007

AbstractDie über den Stand von 1971 hinausgehenden neuen Messungen und Modelle zur Erdexpansion werden diskutiert. Dabei kann die damals getroffene Feststellung, daß es ‐ wenn überhaupt ‐ nur eine „langsame”︁ Expansion der Erde gibt, bekräftigt werden.
Main Features of the Electron Kinetics in Collision Dominated Steady‐State rf Plasmas
Authors: Winkler R. , Wilhelm J. , Hess A. 
Published: May 2007

AbstractThis paper reports about systematic investigations of the velocity distribution function and resulting macroscopic quantities of the electrons in a weakly ionized and spatially homogeneous rf plasma in the molecular gas H2 and about a comparison with an analogous study of the rf plasma in the inert gas Ne for a wide field frequency range. These results are obtained by a strict treatment of the non‐stationary electron Boltzmann equation considering the action of the rf field as well as that of elastic and inelastic electron ‐ neutral gas particle collision processes. Furthermore, such investigations could be extended to very high field frequencies for the rf plasma in neon. This provides the basis for a general characterization of the complex temporal behaviour of the isotropic and anisotropic part of the velocity distribution as well as of the several macroscopic quantities in the range from low to very high field frequencies. The ration of the field frequency to two dissipation frequencies which describe the lumped dissipation of energy and impulse due to elastic and all inelastic collision processes and which are only determined by the atomic data of these processes governs the temporal behaviour of the electron kinetics in the rf plasma in any gas.
On the Recursion Operator for the Infinitesimal Symmetries for Autonomous and Non‐autonomous Systems
Authors: Chowdhury A. Roy , Ahmad Siraj 
Published: May 2007

AbstractRecursion operators for infinitesimal symmetries for a class of nonlinear equations are obtained with the help of the Wronskian formalism of Calogero et al. Our consideration includes both autonomous and nonautonomous systems. The formalism helps us to obtain the symmetry generators and recursion operator for the coupled system of Boomeson equation which is otherwise quite difficult to obtain.
Infinitesimal Bäcklund Transformation and Conservation Laws for Non‐autonomous Systems
Authors: Mahato G. , Chowdhury A. Roy 
Published: May 2007

AbstractWe have observed that it is possible to extend the concept of the infinitesimal Bäcklund transformation of Steudel to the case of non‐autonomous systems. We have discussed the situation with the cylindrical KdV as example. The interesting point to note is that though the B.T. for Ckdv does not possess the usual property of generating one soliton in a single operation, yet it generates an infinite number of symmetries, which corroborates with those obtained through the expansion of the resolvant of the linear operator associated with the equation.
Bianchi I Cosmological Models for Gravitational Field Equations of Fourth Order
Authors: Müller Volker 
Published: May 2007

AbstractAll power asymptotes of anisotropic Bianchi I cosmological models in gravitation theories with linear and quadratic curvature terms in the Lagrange function are obtained. Depending on the dominance of the fourth order terms or matter plus fourth order terms, faster or slower expansion velocities result near the initial singularity. The latter gives solutions which avoid the horizon problem.
Equations of Motion of Glashow‐Salam‐Weinberg Theory after Spontaneous Symmetry Breaking
Authors: Ebner Dieter W. 
Published: May 2007

AbstractWhile for quantum field theoretical calculations it is sufficient to know the Lagrangian, we give here the field equations of the unified gauge‐theory of weak and electromagnetic interactions after spontaneous symmetry breaking. With this approach, inhomogeneous Lorentz conditions for the massive vector bosons Zμ, W are obtained.
The Positron as a Probe for Studying Bulk and Defect Properties in Semiconductors
Authors: Dlubek G. , Brümmer O. 
Published: May 2007

AbstractPositron lifetime measurements are used to study various doped and undoped III–V compound semiconductors like GaAs, GaP, InAs and InP. In some as‐grown crystals native vacancies (V, V) or their complexes with dopants (TeAsV, VPZnInV) are detected with maximum concentrations of a few 1018 cm−3. In undoped GaAs neutral As vacancies V are identified, the concentration of which varies locally. The vacancies have their origin in deviations from the stoichiometrie composition of the compound. They disappear at 500°C. At this temperature defects created by irradiation with fast neutrons anneal also out. The relation between the bulk positron lifetime and the density and polarization of valence electrons is analyzed. Further, the potential of the positron annihilation method in identifying and characterizing vacancy‐type defects in semiconductors is discussed.
Physikalische Probleme der Informationsübertragung über Lichtleiter
Authors: Junge Klaus 
Published: May 2007

AbstractDie herkömmliche rein elektrische Übertragungstechnik über Kabel läßt technische und ökonomische Grenzen erkennen. Die Suche nach neuen Kanälen führte unter anderem in den optischen Bereich, zur Lichtleiter‐Nachrichtenübertragung. Hierfür sind in den letzten Jahren alle Elemente der ersten Generationen in umfangreicher Forschungsarbeit entwickelt worden. Dabei haben moderne Technologien der Mikroelektronik wesentlich zu den erzielten Ergebnissen bei der Herstellung der Lichtleit‐Fasern und der opto‐elektronischen Sende‐ und Empfangsbauelemente beigetragen. Abschließend werden Systemfragen und zukünftige Zielstellungen behandelt.
Technikwissenschaft – Erfinden und Entdecken
Authors: Linnemann Gerhard 
Published: May 2007

AbstractUmrissen wird das allgemeine Ziel der Technikwissenschaft, konstruktiv zu verwerten und „nicht‐natürlich”︁ Entdeckbares zu „erfinden”︁. Wir befinden uns in einer Umwälzung der Technik im Verlauf der wissenschaftlich‐technischen Revolution, auf dem Wege zu einem neuen Techniktyp. Dieser schafft und nutzt die „künstliche”︁ Intelligenz. Dazu benötigt der in der Technik tätige Mensch spezielle Kenntnisse und Erfahrungen in kreativ‐konstruktiver, ‐gestalterischer und erfinderischer Sicht mit dem Einsatz spezieller Strukturen und Sprachen. Vorschläge zur Arbeitsweise in der Technik werden gegeben.
Die Projektor‐Monte‐Carlo‐Methode, Test eines neuen Verfahrens zur Auswertung von Gittereichfeldtheorien mit Fermionen in der Hamilton‐Formulierung
Authors: Ranft J. 
Published: May 2007

AbstractDie bisher bekannten Methoden zur Monte‐Carlo‐Simulation von Gittereichfeldtheorien unter Einbeziehung von Fermionen sind sehr aufwendig und ineffektiv. Deshalb ist die Entwicklung und der Test von Monte‐Carlo‐Methoden zur Behandlung von Fermionen von großem Interesse. In der vorliegenden Arbeit wird die Projektor‐Monte‐Carlo‐Methode erstmals auf eine Eichfeldtheorie mit Fermionen, und zwar auf das massive Schwinger‐Modell, d. h. die Quantenelektrodynamik in 1 + 1 Dimensionen, angewandt. Die berechneten Erwartungswerte für die mittlere Energie und für das Fermionenkondensat stimmen mit den Ergebnissen überein, die mit Hilfe der lokalen Hamiltonschen Monte‐Carlo Methode erhalten wurden. Im Gegensatz zur letzteren Methode sollte es jedoch möglich sein, die Projektor‐Monte‐Carlo‐Methode auch auf Eichfeldtheorien in 2 + 1 und 3 + 1 Dimensionen anzuwenden.
Herausforderungen der Kosmosforschung an die Physik
Authors: Stiller H. , Möhlmann D. , Sauer K. , Wiebicke H. , Franck S. 
Published: May 2007

AbstractDie Kosmosforschung mit ihren physikalischen Experimenten und Beobachtungen direkt im Kosmos gibt für die Physik neuartige Möglichkeiten und damit neue Beiträge zur fundamentalen Frage des Aufbaus der Materie und ihrer Kosmogonie.
Long‐Range Energy Transfer in the Case of Inhomogeneous Spatial Distributions and Indirect Donor‐Donor Interaction
Authors: Schubert Max 
Published: May 2007

AbstractOn the basis of Förster kinetics concerning long‐range energy transfer caused by dipole‐dipole interaction the √t‐deactivation‐law has been derived under the assumption of a homogeneous spatial acceptor distribution (at the end of the forties). Recently, in particular ultra‐short time fluorescence and absorption measurements have shown that on the one hand this law holds in a wide range of physical conditions, but that under other circumstances the experimental results strongly deviate from the √t‐law. In the present paper it is shown that a unified treatment of inhomogeneous distributions and indirect donor‐donor interaction via the acceptors can qualitatively, and in certain cases also quantitatively, remove the discrepancies mentioned. The analysis yields new parameters of dynamical processes.
The Total n‐p Capture Cross Section Measured at En = 25 MeV
Authors: Stiehler Thomas , Mösner Jürgen , Schmidt Günter , Möller Karsten , Neubert Waldemar , Pilz Wolfgang , Kühn Berthold , Hutsch Jochen 
Published: May 2007

AbstractThe total cross section of the capture reaction n + p → d + γ has been measured at En = 25 MeV using a hydrogen gas target containing two multiwire proportional counters and a scintillation counter telescope. The resulting value δtot = (26.6 ± 1.5) μb is in line with the other n‐p capture data in the energy range 14‐73 MeV. The experimental data are compared with theoretical predictions.
Superfluorescence from a System of Atoms in Front of a Mirror
Authors: Steudel H. 
Published: May 2007

AbstractThe initiation of superfluorescence from atoms in front of a plane mirror is investigated both for a 3 × 3 × 3 lattice and for random distributions of N = 40 atoms. Growth rates of dominant radiation modes are computed, and the corresponding radiation patterns are depicted. As a main result some preference of radiation directions parallel to the mirror plane is found.
Gauge Fields in General Parametrical Approach and Their Finslerian Reduction
Authors: Asanov G. S. 
Published: May 2007

AbstractThe covariance principle of general relativity is extended to internal space. Associated gauge fields and tensors are systematically described, whereupon the variational principle is set up for all gauge fields by applying a Palatini‐type method, thereby giving rise to an attractive self‐contained theory in which the Einstein equations are intrinsically synthesized with the generalized Yang‐Mills equations. General gauge‐covariant physical field equations are formulated, showing that currents, external + internal spin tensors, and energy‐momentum tensors can be introduced unambiguously under these general conditions and that the associated conservation laws can be derived. The electromagnetic field finds its gauge‐geometric origin as the gauge field related to internal densities. To be operative with the tensor indices of external and internal types, this general theory must be bimetric. The assumptions that the gauge‐covariant derivatives of metric tensors should vanish simplify the theory to the level of a Finslerian gauge approach.
Topology and Fermionic Condensate
Authors: Kulikov I. , Pronin P. 
Published: May 2007

AbstractThe purpose of this paper is to investigate an influence of a space‐time topology on the formation of fermionic condensate 〈φφ〉 in the model with four‐fermion interaction (φφ)2. The value for the space‐time with topology of R1 × R1 × S1 is found. Moreover a relation of the value of fermionic condensate to a periodic length is studied. In this connection the possibility of a relation of the topologic deposits to structure of hadrons is discussed.
A Rule for the Equilibrium of Forces in the Hermitian Theory of Relativity
Authors: Antoci S. 
Published: May 2007

AbstractWhen the behaviour of the singularities, which are used to represent masses, charges or currents in exact solutions to the field equations of the Hermitian theory of relativity, is restricted by a no‐jump rule, conditions are obtained, which determine the relative positions of masses, charges and currents. Due to these conditions the Hermitian theory of relativity appears to provide a unified description of gravitational, colour and electromagnetic forces.
On the Significance of the Internal Quasi‐Lorentz‐Group in Continuum Mechanics
Authors: Leihkauf H. 
Published: May 2007

AbstractWe give a short discussion of usual representation of geometric approach to modern continuum mechanics. As a consequence we propose a formulation of this theorie based on the internal quasi‐Lorentz‐group. The aim of our method is to get an unitary geometrisation of the theory of condensed structures. The result is: For an internal observer the theory of the real solid is the theory of totally geodesic three‐dimensional hypersurfaces in a genuin four‐dimensional non Riemannian “sound space time”.
Electron Kinetics with Attachment and Ionization from Higher Order Solutions of Boltzmann's Equation
Authors: Winkler R. , Braglia G. L. , Wilhelm J. 
Published: May 2007

AbstractAn appropriate approach is presented for solving the Boltzmann equation for electron swarms and nonstationary weakly ionized plasmas in the hydrodynamic stage, including ionization and attachment processes. Using a Legendre‐polynomial expansion of the electron velocity distribution function the resulting eigenvalue problem has been solved at any even truncation‐order. The technique has been used to study velocity distribution, mean collision frequencies, energy transfer rates, nonstationary behaviour and power balance in hydrodynamic stage, of electrons in a model plasma and a plasma of pure SF6.The calculations have been performed for increasing approximation‐orders, up to the converged solution of the problem.In particular, the transition from dominant attachment to prevailing ionization when increasing the field strength has been studied.Finally the establishment of the hydrodynamic stage for a selected case in the model plasma has been investigated by solving the nonstationary, spatially homogeneous Boltzmann equation in twoterm approximation.
Symmetry Breaking Due to Conformally Invariant Scalar Field
Authors: Bleyer U. , Nikolaenko V. M. 
Published: May 2007

AbstractIn the framework of Weyl invariant gravitational field theory including torsion coupled to a scalar field with arbitrary selfinteraction it will be shown that any solution of such a generalized Goldstone model contains the conformally invariant field of a massless scalar particle. Due to this fact it may happen that dynamical symmetry breaking becomes impossible.
Dynamic Field‐Theoretic Approach to a Disordered Model Superconductor
Authors: Kolley E. , Kolley W. 
Published: May 2007

AbstractOn the basis of the attractive Hubbard model with a Gaussian random potential we describe superconductivity in the presence of quenched disorder. A dynamic path‐integral formalism with an 8‐component Keldysh‐Nambu spinor is shown to be convenient for solving the averaging problem without the recourse to the replica trick. The effective action is bosonized in terms of collective variables, namely local Q‐matrices and real space pair fields. Saddle point values are calculated in two simplified limits.
Über das monotone Verhalten gewisser Zustandssummen bei Temperaturausgleich
Authors: Zylka Christian 
Published: May 2007

AbstractWir lenken die Aufmerksamkeit darauf, daß die kanonische Zustandsumme Z(β1, β2, …, βn) ≡ Z(β) eines aus n unabhängigen Teilsystemen zusammengesetzten thermodynamischen Systems eine schurkonvexe Funktion ist. Dabei bezeichnet βi die inverse Temperatur des i‐ten Teilsystems. Falls die innere Energie proportional zu β ist ‐ wie etwa bei Spinsystemen in Hochtemperatur‐Näherung ‐ so folgt aus der Schurkonvexität, daß beliebiger Temperaturausgleich zwischen den Teilsystemen stets zu einem Abfallen von Z(β) führt.
On the Lie Symmetry, Conservation Laws and Painlevé Analysis for the Viscous Transonic Equation
Authors: Mukherjee Jayasree , Choudhury A. Roy 
Published: May 2007

AbstractThe properties of the nonlinear viscous transonic equation is analysed in detail. The Painlevé test shows that it is not completely integrable. The equation does not reduce to a member of Painlevé class by any similarity transformation of variables.
A Multilevel Shape Fit Analysis of Neutron Transmission Data
Authors: Naguib K. , Sallam O. H. , Adib M. , Ashry A. 
Published: May 2007

AbstractA multilevel shape fit analysis of neutron transmission data is presented. A multilevel computer code SHAPE is used to analyse clean transmission data obtained from time‐of‐flight (TOF) measurements. The shape analysis deduces the parameters of the observed resonances in the energy region considered in the measurements. The shape code is based upon a least square fit of a multilevel Briet‐Wigner formula and includes both instrumental resolution and Doppler broadenings. Operating the SHAPE code on a test example of a measured transmission data of 151Eu, 153Eu and natural Eu in the energy range 0.025‐1 eV accquired a good result for the used technique of analysis.
On the Stability of Davey‐Stewartson System ‐ A Dressing Operator Approach
Authors: Sen Shibani , Chowdhury A. Roy 
Published: May 2007

AbstractThe problem of stability associated with perturbations around solitonic excitations of Davey‐Stewartson equation in three dimension is discussed within the framework of dressing operator approach of Zakharov. The system is stable so far as long time behaviour is concerned and unstable for large transverse directions depending upon the sign of the eigenvalue of the linearized problem.
The Odd SO(3,3) Fusions and the Gauge Principle
Authors: Scheurich H. 
Published: May 2007

AbstractThe origin of the gauge principle generating electroweak and gravistrong interactions is shown to lie already in the quaternionic vacuum. The leptonic Dirac equations gauged in respect of the electroweak and the linearized gravistrong field are derived from the SO(3,3) fusion 6 × 4 = 20 + 4 as a part of 4 × 4 × 4. The procedure leading to respective equations including self‐interactions and gauge coupling to the full nonlinear gravistrong field via 20″ × 4 = 60 + 20 as a part of 4 × 4 × 4 × 4 × 4 is outlined.
The Internal Bremsstrahlung Accompanying the Electron Capture Decay of 57Co
Authors: Basha A. M. , El‐Konsol S. , Khalil F. 
Published: May 2007

AbstractThe internal bremsstrahlung (IB) spectrum accompanying the electron capture decay of 57Co have been measured. The measured spectrum was then analyzed into its constituting gamma lines. The proper corrections for the analyzed IB (EC) spectrum have been taken into account. A comparison between the present experimental results of the IB (EC) probability per electron capture and those calculated theoretically according to Martin and Glauber theory have been done. This comparison shows a good agreement throught the investigated range of energy (300 up to 650 keV).
Spin Instability in Nuclear Matter and the Skyrme Interaction
Authors: Mansour H. M. M. 
Published: May 2007

AbstractIn the present work the problem of spin instability of nuclear matter with the Skyrme interaction is analyzed. The three‐body part of the interaction is replaced by using a density dependent potential which is a modification to that given previously by Dabrowski. The symmetry energies are calculated and their rearrangement corrections. Good agreement is obtained with previous calculations.
Neutron Matter Properties Using Skyrme Interaction
Authors: Mansour H. M. M. , Guirguis Jannette W. , Abdelmageed A. I. , Hager S. A. 
Published: May 2007

AbstractThe purpose of the present work is to extend earlier nuclear matter calculations to study the properties of neutron matter. The binding energy per particle, symmetry energy, single particle potential, effective mass, and magnetic susceptibility are calculated using a modified Skyrme interaction. These are calculated as a function of the Fermi momentum kf in the range 0 < kf < 2 fm−1. Two sets of the interaction parameters are obtained by fitting the interaction parameters using the available information on neutron matter. Relativistic corrections to the order 1/c2 are also calculated. The relativistic corrections are very small and they increase as kf is increased.
On the Lie Group of Projective Canonical Transformations
Authors: Flach G. , Kirschbaum D. 
Published: May 2007

AbstractThe transformation properties of the projective canonical group are considered. It is shown that the group acts transitiv on functions defined on configuration space but not transitiv on those defined on the phase space. We prove moreover that this group is the largest finite‐dimensional Lie group of point transformations determined on the configuration space.
Homoclinic Bifurcations in Simple Parametrically Driven Systems
Authors: Bruhn B. 
Published: May 2007

AbstractIn this paper we consider the onset of chaotic particle motion in a perturbed Morse potential and the homoclinic bifurcations in a parametrically driven Lorenz system. The Melnikov‐Keener method is used to derive bifurcation conditions for the parameters of the dynamical systems. For some selected parameter values the theoretical predictions are checked by numerical experiments.
Inflation and the Rotation Problem
Authors: Soleng Harald H. 
Published: May 2007

AbstractThe effect of an inflaton scalar field on cosmic rotation is discussed. It is shown that any physically reasonable inflaton scalar will dilute the cosmic vorticity by a factor of R−3γ when the false vacuum decays into matter. Since vorticity decays during inflation as R3γ‐5, this leads to a total decay by a factor of R5, which is not dependent on the equation of state of the rotating non‐vacuum component of the energy‐momentum tensor.
Liénard‐Wiechertsche Potentiale für Multipolquellen
Authors: Mitskiévič N. V. 
Published: May 2007

AbstractDie Liénard‐Wiechertsche Formel wird auf den Fall einer punktförmiger Multipolquelle verallgemeinert, die zeitabhängige Multipolmomente willkürlicher Stufen hat und einer beliebigen zeitartigen Weltlinie folgt. Die erhaltenen Potentiale sind strenge Lösungen von Gleichungen der Felder willkürlicher ganzzahliger Tensorstufe s. Wenn s ⩾ 2 ist, so wird die Freiheit der Bewegung der Quelle von den Feldgleichungen eingeschränkt.