bluuebunny/crossref_metadata_2025 huggingface dataset:
On Equilibrium Configurations in Continuum Mechanics of Structural Defects
Authors: Günther H.
Published: May 2007

We consider the determination of the theory by a second order tensor field gik and affinity Γfik. By variational principle for Einstein‐Hilbert Lagrangian solid state equilibrium positions of the ideal and real crystal will be described. On account of external Galilei‐invariance this theory affords an invariant three dimensional geometry at most being able to produce a stable static equilibrium of defects. The motion of defects is related to the theory of invariants of the internal group of field equations produced by this theory in strong analogy to Maxwell's electrodynamics. The elastic ether concept for the theory of light affords the idea of a gauge field approximation of continuum mechanics fitting linearized Einstein‐Hilbert Lagrangian approach. The stress and strain space duality has to be understood on this background.
A Relativistic Model of the Isotropic Oscillator
Authors: Atakishiyev N. M. , Mir‐Kasimov R. M. , Nagiyev Sh. M.
Published: May 2007

For a three‐dimensional model of the harmonic oscillator in the relativistic configurational r‐representation wave functions in the spherical coordinates r = (r, Θ, ϕ) are found. The generating function, orthogonality and various recurrence relations for the radial part of the wave function are obtained. The radial and orbital quantum numbers raising and lowering operators are defined and the dynamical symmetry group is constructed by means of the Infeld‐Hull factorization method.
Reflections Concerning Niels Bohr's Refutation of the Einstein‐Podolsky‐Rosen‐Paradox
Authors: Fuchs Klaus
Published: May 2007

The controverse discussion between Bohr and Einstein concerning the interpretation of quantum theory is resumed by a reappraisal of some arguments in the view of epistemological problems, which have come to the fore in recent times.
Lebensdauermessung am Ionenstrahl bei kollinearer Laseranregung
Authors: Breunig Th. , Elbel M. , Quad R.
Published: May 2007

Die Methode der kollinearen Laserspektroskopie, die sich durch eine Reduktion der Dopplerbreite um bis zu zwei Größenordnungen auszeichnet, erlaubt auch eine Bestimmung der Lebensdauer angeregter Ionenterme nach dem Verfahren des Level‐Crossing. Diese Methode ist attraktiv, weil die Ionen im Strahl in fast idealer Weise von Umgebungseinflüssen frei sind. Die Restdopplerbreiten sind allerdings noch breit gegen natürliche Linienbreite und Laserlinie. Wir konnten zeigen, daß in diesem Fall Lorentzkurven erhalten wurden, die mit Summen von Gaußkurven multipliziert sind. Die letzteren sind meist merklich breiter als die Lorentzkurven, überdies berechenbar, wenn man die Geschwindigkeitsverteilung der Ionen gemessen hat. Experimentell beobachtete Einbrüche in der Linienmitte wurden auf optisches Pumpen zurückgeführt und durch Lösen der Bewegungsgleichungen der beteiligten statistischen Tensoren verifiziert. Lebensdauern zweier Terme konnten ermittelt werden.
Das EPR‐Paradoxon als makroskopisches Experiment und seine Auswirkungen auf unsere Vorstellung von Physik
Authors: Ludwig G.
Published: May 2007

Es soll gezeigt werden, daß die EPR‐Experimente allein im makroskopischen Bereich der Apparaturen beschrieben werden können. Diese Beschreibung oder auch die entsprechende mit Hilfe von Mikrosystemen ist ohne jede Widersprüche. Eine ontologische Interpretation der Experimente ist sowohl für die makroskopische wie mikroskopische Beschreibung der Experimente problematisch. Die korrekte, physikalische Beschreibung der EPR‐Experimente führt dazu, viele Vorurteile darüber zu vermeiden, was Physik ist.
Physikalische Bilder ‐ Besinnung auf eine fachdidaktische Aufgabe
Authors: Mann Are
Published: May 2007

Physiker arbeiten an Darstellungen der Natur, d.h. sie suchen mit physikalischen Mitteln Bilder zu schaffen, die ihnen Naturzusammenhänge klarer und eindringlicher vor Augen führen. Schulunterricht soll jedem die Möglichkeit eröffnen, Physik in solchem Sinne ‐ wenn auch in bescheidenem Rahmen ‐ selbst zu treiben. Allzuoft bleibt diese Wissenschaft jedoch den Schülern ein kahles Gerüst und führt sie nicht zu inhaltsreichen Bildern. Es wird vorgeschlagen, Schulphysik mehr unter dem Gesichtspunkt einer Kunst zu sehen, die wirklich zu betreiben aber Muße erfordert.
Photo‐Induced Metastable Effects in Hydrogenated Amorphous Silicon (a‐Si:H)
Authors: Fuhs W. , Mell H. , Stuke J. , Thomas P. , Weiser G.
Published: May 2007

Light induced changes of electronic properties are studied in glow discharge deposited a‐Si: H‐films by ESR, field effect, DLTS and electronic transport. These effects are caused by silicon dangling bonds generated by recombination processes, which raise the density of states near midgap. The concomitant increase of potential fluctuations indicates that these defects are inhomogeneously distributed.
Newtons Wissenschaftslehre als Basis der Quantenphysik
Authors: Bopp Fritz
Published: May 2007

Es ist richtig zu sagen, die Quantenphysik folge nicht aus der auf Newtons Prinzipien beruhenden klassischen Physik. Es ist aber auch richtig, daß Newtons Wissenschaftslehre, die eng mit der Platonschen zusammenhängt und über diese hinausgeht, von der Quantenphysik nicht berührt wird, wie an anderer Stelle gezeigt ist. Hier wird Newtons Wissenschaftslehre genauer analysiert und der Unterschied zur kartesischen herausgearbeitet, was durch die Newtontradition verschleiert wird. Am Ende werden die Ergebnisse an Beispielen aus der Quantenoptik erläutert.
Adsorption, Desorption, Dissoziation und Rekombination von SO2 an einer Palladium(111)‐Oberfläche
Authors: Kölzer J. G. , Wassmuth H.‐W.
Published: May 2007

Die Adsorption, Desorption sowie Zerfalls‐ uud Aufbaureaktionen von SO2 an Pd(1 1 1) wurden mit LEED, AES, Thermischer Desorptions‐Massenspektrometrie und Molekularstrahlstreuung im Temperaturbereich 160‐1200 K untersucht. Bei 160 K adsorbiert SO2 molekular und ungeordnet; die Precursor‐gesteuerte Adsorption mit einem Anfangshaftkoeffizienten s0 = 1 führt bei Sättigung zu einem Bedeckungsgrad Θ ≈ 0,3. Beim Hochheizen der Adschicht desorbiert ausschließlich SO2, und zwar im α‐Peak (Tmax = 240 K) direkt aus dem Zustand (SO2)ad und im β‐Peak (Tmax = 330‐370 K) als Produkt der Rekombination von (SO)ad und Oad. Ein großer Teil des bei der SO2‐Dissoziation freiwerdenden Sauerstoffs wird in den „Subsurface”︁‐Bereich inkorporiert, so daß eine atomare S‐Bedeckung mit ΘS = 1/7 zurückbleibt, die eine (\documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt 7 {\rm x}\sqrt 7 $\end{document}) ± 19,1°‐Überstruktur ausbildet. Diese Struktur wird auch nach Hochheizen einer bei 320 K hergestellten (2 × 2)‐SO‐Sättigungsbedeckung mit ΘSO = 0,5 sowie nach SO2‐Exposition bei T > 500 K beobachtet, wo sie Bedeckungsgraden ΘS von 3/7 und 2/7 entspricht. Weiterhin wurden der „Vergiftungseffekt”︁ durch adsorbierten Schwefel auf die dissoziative Adsorption von Sauerstoff und die S‐Oxidation durch Hochheizen einer OS‐Koadsorptionsphase untersucht. Insgesamt wurden folgende reaktionskinetische Parameter (Aktivierungsenergien und Vorfaktoren) bestimmt: magnified image.
Non‐Maxwellian Characteristics of the Energy Distribution of Thermal Electrons in the Upper Atmosphere
Authors: Amemiya H.
Published: May 2007

The Result of Measurements of the energy distribution of thermal electrons in a midlatitude ionosphere is presented. A comparison is made in particular between the characteristics at sunrise and sunset periods because of the effect of vibrationally excited nitrogen molecules.

At sunrise the distribution has a little‐irregularity but the middle and higher energy parts (0.2‐0.5 eV) deviate from the Maxwellian distribution only slightly at all heights. The electron temperature varies from 900 K to 1300 K between 130 km and 300 km. These values are higher than the kinetic temperature of neutral particles but comparable with the theoretical values of the vibration temperature of N2.

At sunset small bumps due to non‐thermal electrons are seen on the high energy tail between 108 and 160 km, their density being from 5 × 10−3 to 1 × 10−2 of that one of the thermal electrons. Above 170 km (F‐layer) the deviation of the distribution from the Maxwellian one becomes smaller. The electron temperature varies from 500 K to 900 K between 100 km and 220 km. These values are higher than the kinetic temperature but lower than the theoretical values of the vibration temperature of N2. A mechanism of the appearance of non‐thermal electrons is considered to be due to super‐elastic collisions with vibrationally excited N2.
High‐Field Carrier Transport in Inhomogeneous Semiconductors
Authors: Böer K. W.
Published: May 2007

The carrier transport in inhomogeneous solids is reevaluated in respect to the differences between a built‐in field within a space charge region and an external field, and related to differences in carrier redistribution and carrier heating, resulting in a different field‐dependence of the mobility. With the assistance of electrostatic and electrochemical potential distributions the regions of substantial carrier heating can be identified as regions in which the current is carried by diffusion only (DO), or by drift only (DRO) in forward (or low reverse), and in high reverse bias respectively, and are distinguished from the region of a major electrostatic potential drop (Boltzmann region) in which the net current is small compared to drift and diffusion. In junction devices major carrier heating does only occur in DO‐ and DRO regions, and only for minority carriers.
NMR‐spektroskopische und Röntgen‐diffraktometrische Untersuchungen zur Wechselwirkung zwischen Cellulose und Natronlauge
Authors: Philipp B. , Fink H.‐P. , Kunze J. , Frigge K.
Published: May 2007

Struktur und Bildungsweise von Alkalicellulose werden mittels CP/MAS‐13C‐NMR‐Spektroskopie, 23Na‐NMR‐Spektroskopie und Röntgen‐Weitwinkelstreuung untersucht. Die Wechselwirkung der Natronlauge mit Cellulose führt zu Konformationsänderungen am Makromolekül, die im Zusammenhang mit irreversibel verlaufenden Gitterumwandlungen diskutiert werden. Die Bedeutung der übermolekularen Struktur des Polymers wird anhand des Modelles uneinheitlicher Fransenfibrillen demonstriert.
Was sind und was bedeuten die Elementarkonstanten?
Authors: Rompe Robert , Treder Hans‐Jürgen
Published: May 2007

Eine Diskussion über Elementarkonstanten und die damit verbundenen Probleme, wie sie in den Beiträgen dieses Heftes auftreten.
A Modification of Projective Spacetime by Finite Self‐Interaction Models of Virtual Leptons and Quarks and the Electroweak GWS Standard Model
Authors: Scheurich H.
Published: May 2007

From the projective Dirac equation in a six‐dimensional Kleinian space R(3, 3) are derived finite‐rotation‐group models as self‐interaction models of virtual leptons and quarks. The quaternion group underlying them is considered as a substructure group of projective spacetime. A finite hypersherical carrier of the self‐interaction models is embedded into projective spacetime by means of the Planck length L0 = (ħG/c3)1/2 as a physical unit length. The corresponding modification of metrics in the Planck domain becomes apparent to be equivalent to the rǒle of the Higgs field in the electroweak GWS standard model.
Unification Based on ElectromagnetismA Simple Composite Model of Particles
Authors: Barut A. O.
Published: May 2007

The complex machinery of gauge theories and QCD is not the only possible avenue to understand the physics of elementary particles. There is another simple and more direct approach based on absolutely stable particles as constituents of all other particles. Mathematically the ensuing group structure is identical to the quark‐lepton model, but the dynamics and the underlying physics is different. How all forces of elementary particles are already dynamically unified under electromagnetism is discussed.
Description of Pulse Propagation in Optical Strip Waveguides by the Generalized Nonlinear Schrödinger Equation
Authors: Eichhorn H.
Published: May 2007

Taking into consideration the transverse confinement, the dispersion of the linear as well as of the nonlinear part of the refractive index and the nonlinear interaction of the electromagnetic field with the guiding material, the yielding equation for the envelope function of the fundamental mode propagating in a strip waveguide is the generalized nonlinear Schrödinger equation. In contrast to the nonlinear Schrödinger equation, solitons of the generalized nonlinear Schrödinger equation exist in the regimes of negative and positive group dispersion and are asymmetric.
Apodisation für die beugungsbegrenzte Abbildung des Achsenpunktes mit rotationssymmetrischen optischen Systemen
Authors: Haferkorn H.
Published: May 2007

Es wird eine Pupillenfunktion vorgeschlagen, mit der das Beugungsintegral unter Berücksichtigung der Apodisation geschlossen lösbar ist. Die Apodisation nach einer Zylinderfunktion bringt eine größere Intensität im Zentrum des Beugungsbildes und ein besseres Auflösungsvermögen als die Apodisation nach einer Gauß‐Funktion mit sich.
Hermitizität und Eichinvarianz
Authors: Treder H.‐J.
Published: May 2007

Die Forderungen der Hermitizität und der Eichinvarianz werden in der Hermiteschen Relativitätstheorie (HRT) durch verschiedene Auffassungen über das Wesen der Hermitizität in unterschiedlicher Weise dargestellt. Aber alle hermiteschen Gleichungssysteme müssen die schwachen Einsteinschen Gleichungen erfüllen, welche den Einstein‐Schrödingerschen Gleichungen äquivalent sind.
Dispersion and Spontaneous Current Phenomena in NH4Cl Single Crystals
Authors: El‐Kabbany F.
Published: May 2007

The effect of frequency and d.c. biasing on the dielectric constant of NH4Cl single crystal samples was studied. A dispersion phenomenon was observed in the frequency range 105‐108 Hz. This was attributed to a piezoelectric effect.

The present study revealed that a spontaneous electric current of the order 10−12 A was found to accompany the order ‐ disorder process. This current showed a clear singnal in the phase transition region of the order‐disorder transition III‐II of NH4Cl. This singnal was well controlled by the application of a polarizing electric field so that its amplitude could be increased, decreased, vanish or even reversed by the application of an appropriate external electric field.
Energy Levels of the Single Excited States in the Boron Isoelectronic Sequences
Authors: El‐Sherbini Th. M. , Mansour H. M. M. , Farrag A. A. , Rahman A. A.
Published: May 2007

Energy levels of the single excited 1s22s2ns (2S), 1s22s2np (2P), 1s22s2nd (2D) and 1s22s2nf (2F), n = 3‐8 states for the boron isoelectronic sequence are calculated using the simple configuration Hartree‐Fock method. Good agreement is obtained between our results and previous experimental and theoretical data.
Nuclear Collective Rotations and the Single Particle Motion in a Rotating Potential
Authors: Osman A. Ahmed , Allam M. A.
Published: May 2007

The heavy and medium nuclei with angular high momentum are reconsidered. The study of these nuclei is introduced according to the way of building up the angular momentum. At high angular momentum, the moments of inertia of that nuclei are investigated. A study for the path of the Yrast spectra is given in the deformation space. Then, the nuclear collective motions and the single particle motion in a rotating field are considered and studied in both cases of the absence and the presence of pair correlations.
Neutron Distributions in Ducted Egyptian Ilmenite Concrete Shields
Authors: Makarious A. S. , Ahmed F. M. Sayed
Published: May 2007

In this work the measurement of neutron distributions along and normal to the axis of air filled ducts with different duct diameters pierced in ilmenite concrete have been carried out. The data show the dependence of the neutron doses on the duct length and diameter. The neutron distributions along the duct axis were compared with the corresponding distributions in solid ilmenite concrete.

Semiempirical formulae have been derived fitting well with the experimental data obtained.
The Weak Energy Condition and Singularities in Classical Free N = 1 Supergravity
Authors: Pullin Jorge
Published: May 2007

With the use of the modification of the weak energy condition for theories with torsion developed by Hehl, we analyse classical free N = 1 supergravity in the hope that spin‐spin contact interactions may avert singularities, as happens in the neutrinic case. We find that this does not happen, since the appearence of singularities is conditioned by the cosmological model of the gravitino field in consideration. We present a very simple singularity free model for a spatially homogeneous Rarita‐Schwinger field in a Robertson‐Walker spacetime.
Shower Particle Multiplicity Distribution in High Energy Nuclear Reactions
Authors: Hussein M. T. , Hassan N. M. , Hegab M. K.
Published: May 2007

The multiplicity distributions of charged shower particles in high energy reactions are studied in the framework of a statistical model based on the approximation of the phase space integral. The model is first applied to the proton‐proton collisions and then further extended on geometrical basis to include proton‐nucleus and nucleus‐nucleus collisions. Although the model is parameter free, it gives quite satisfactory results in comparison with experimental data.
Analytical I‐Dependent Folding Potential According to Alpha‐Cluster Model ‐I
Authors: Hassan M. Y. M. , Comsan M. N. H. , Tageldin I. M. A.
Published: May 2007

The folding model is applied to calculate the nucleon and alpha‐nucleus interaction for 12C and 16O. The matter densities are obtained using the alpha‐cluster model. Analytical l‐dependent expressions for the folding potential as well as the deformation parameters are given. The effect of applying different nucleon‐nucleon forces is discussed.
The Internal Bremsstrahlung Accompanying the β‐Decay from 185W
Authors: Basha A. M. , Ragab H. S. , El‐Konsol S. , Osman O. M.
Published: May 2007

The internal bremsstrahlung (IB) spectrum accompanying the β‐decay from 185W radionuclide has been measured. The obtained spectrum was analyzed into its constituting gamma lines taking into account all the proper corrections. The analyzed spectrum was compared with those theoretically calculated. The experimental results for the IB probability were found to be in good agreement with theoretical calculations especially with the shape corrected modified KUB theory of Nilsson up to 357.7 keV.
The Influence of Cation Substitution on the Magnetic Behaviour of Magnesium Ferrite
Authors: Fayek M. , Elnimr M. , Nada N. , Saleh H. , Eid Y.
Published: May 2007

New polycrystalline specimens of the ferrites Mg1.5Fe1Si0.5O4, Mg1.5Fe1Ge0.5O4, Mg1.5Fe1Ti0.5O4 and Mg1.66Fe1Sb0.33O4 have been prepared and studied by nuclear gamma ray resonance technique, over a wide temperature range. All samples are monophasic spinel type ferrite with cubic symmetry. Mössbauer effect spectra of the composition containing Si4+ or Ge4+ show magnetic hyperfine splitting at room temperature, and Néel transition points are found around 750 and 570 K for the two compounds respectively. The spectrum of Mg1.5Fe1Ti0.5O4 is paramagnetic at 300 K while at 78 K shows a superposition of a broad six lines pattern and a central quadrupole doublet. The sample with pentavalent antimony exhibits a strong ferromagnetic relaxation at 78 K where it shows six broad lines with enhancement of the two inner lines as the temperature is risen. For all compositions the Mössbauer effect parameters are determined and cation distributions are deduced and its effect on the magnetic behaviour is discussed.
Determination of Neutron Spectra in a Graphite Sphere for Fusion Reactor Studies
Authors: Bashter I. B. , Cooper P. N.
Published: May 2007

Calculated and experimental results for the neutron spectra at different radii in a graphite sphere irradiated with 14.1 MeV neutrons were shown to be in satisfactory agreement over the energy range 14.1 to 1.8 MeV neutrons. A group of curves were constructed which gives the radius of a graphite sphere shield required to attenuate the neutron intensity to a certain value. The data set used in the present work, with carbon‐12 cross section, is shown to be useful for spherical calculations.
Processes with Higgs Scalar Bosons in External Electromagnetic Fields
Authors: Ternov I. M. , Rodionov V. N. , Studenikin A. I.
Published: May 2007

In this paper we consider the processes with real and virtual Higgs scalar H‐boson in the presence of an external constant electromagnetic field. We get formulae for the probability of the H‐boson emission by a charged lepton and the field radiative H‐boson effects (i.e. the contribution to the mass and the anomalous magnetic moment of the lepton.
Detailed I.R. Study of the Phase Transition in the System AgNO3‐Fe(NO3)3
Authors: El‐Kabbany F. , Taha S. , Tosson M.
Published: May 2007

A complete infrared study of the mixed crystal system of AgNO3 and Fe(NO3)3 is carried out in the region 400–4000 cm−1. The study includes internal fundamental normal vibrations of the NO3− ion in the ordered and disordered phases of AgNO3 at different values of the ferric concentration, I.R. spectra, spectral band shape intensities, and frequencies of the internal modes as functions of the ferric ion concentration. Special attention is paid to bending mode, combination mode, asymmetric stretching mode, and over‐tone. The rotational energy barrier is determined at different concentration of the ferric ions in the system of AgNO3‐Fe(NO3)3.
Strings and Antisymmetric Tensor Fields
Authors: Solodukhin S. N.
Published: May 2007

The string model described by antisymmetric tensor fields which in many respects are analogous to spinors, is considered. So new possibilities in constructing the unified theory of physical interaction is appeared.
On the Einstein Relation in Ternary Semiconductors in the Presence of Crossed Electric and Magnetic Fields
Authors: Mondal M. , Ghatak K. P.
Published: May 2007

We investigate theoretically the Einstein relation for the diffusivity‐mobility ratio of the electrons in ternary semiconductors at low temperatures in the presence of crossed electric and quantizing magnetic fields on the basis of threeband Kane model. It is found, taking n‐Hg1‐xCdxTe as an example, that DMR shows an oscillatory magnetic field dependence. Besides, the DMR increase both with increasing electron concentration and decreasing alloy composition respectively.
A First Order Generalized Thomas‐Fermi Approximation for the Electron Density in Inversion Layers
Authors: Übensee H. , Paasch G.
Published: May 2007

An operator evaluation of the one‐particle density matrix of a degenerate system of independent particles in first order with respect to the gradient of the potential developed by Macke and Rennert yields an analytic expression for the particle density. This method is extended here to potentials with an infinite step and to finite temperatures – a situation which is characteristic for inversion electrons in MIS‐systems. The resulting density can be expressed as the Airy transform of the zeroth order (local density approximation). The first order yields both the tunneling into the classically forbidden region and oscillations of the density near the step of the potential. The operator evaluation of the density matrix is shown to be equivalent to solving a Schrödinger like equation. The first order density yields results for the subband structure of (100)Si inversion and accumulation layers at OK in remarkable agreement to density functional calculations of Ando.
In‐Beam γ‐Ray Studies of Band Structures in Ho151
Authors: Mansour N. , Bayomy T. , Awwad Z. , Farhan A.
Published: May 2007

We reported here the level structure in the ood proton nucleus Ho151. High spin states in Ho151 have been populated in the Sn122 (Cl35, xyzγ) reaction. The level structure has been established up to an energy of 9.9 MeV and spin value I = 63/2. The systematic behavior of the level pattern of Ho151 nucleus is discussed in the context of the high‐spin structure in the neighbouring nuclei. Most of the proposed level configurations can be explained by the coupling of h 11/2 protons to f 7/2 and/or h 9/2 neutrons.
IR Spectral Analysis of the Mixed Crystal System of AgNO3 and Sr(NO3)2
Authors: El‐Kabbany F. , Taha S. , Tosson M.
Published: May 2007

IR spectroscopy is utilized to analyse the mixed crystal system of AgNO3 and Sr(NO3)2 in the ordered phase II and disordered phases of silver nitrate.

The study aims mainly to clearify the change and the affect of partial replacement of Ag+ ion by Sr++ ion in the mixed crystal system of the two metal nitrates. The change in the rotational energy barrier of the nitrate group was also checked.
Mass Distributions and Charge Dispersion for the Nuclear Fission
Authors: Osman Ahmed , Abdel‐Latif A. M.
Published: May 2007

The theory of nuclear fission is reconsidered by introducing the charge asymmetry in the asymmetric two center shell model as a dynamical collective coordinate. The quantum mechanical fluctuations, which are accompanied with the collective motion as a function of the mass asymmetry, are responsible for the mass distributions in nuclear fission. Numerical calculations are carried out for the mass distributions and charge dispersions for the nuclear fission of the 236U and 238U nuclei. The present obtained theoretical calculations are in good agreement with the experimental measurements.
Huygens' Principle on Petrov Type D Space‐Times
Authors: Wünsch V.
Published: May 2007

Generalizing the recently by J. Carminati and R. McLenaghan [2] obtained results it is shown that there exist no Petrov type D space‐times on which the conformally invariant scalar wave equation, or Maxwell's equations, or Weyl's equations satisfy Huygens' principle.
Dielectric and Polarization Studies of KNO3 Thin Layers
Authors: El‐Kabbany F. , Mahrous S.
Published: May 2007

Ultrapure and homogeneous KNO3 thin layers are subjected to dielectric and polarization measurements over a wide temperature range. The dielectric results obtained are discussed on the assumption of probable formation and migration of vacancies. The variation of polarization with the applied field was found to be nonlinear and the polarization reversal occurs at a critical value of the applied field of strength 11 kV/cm. This value is in good agreement with the value of the coercive field determined previously by the ferroelectric hysteresis loops.
Mathematical Foundations of the Dimensional Method
Authors: Rufa G.
Published: May 2007

We summarize and discuss important mathematical foundations concerning the dimensional method. To this end we carefully discuss the assumptions as well as the derived fundamental statements. We define and investigate the uniqueness of the ϵμνστ tensor in n dimensions and, related to this, the uniqueness of γ5. Furthermore, we develop an algorithm which allows the calculation of a set of scalar multi‐loop integrals with masses in a systematic way. To demonstrate and test the algorithm we rederive a set of scalar integrals which are important in calculations at the one and two loop level.
Electrical and Thermal Properties of NH4BrxCI1‐x Single Crystal
Authors: El‐Kabbany F. , Tosson M. , Taha S.
Published: May 2007

The effect of partial replacement of Cl− ions by Br− ions in the mixed system of ammonium chloride and ammonium bromide during a set of thermal heating cycles is studied. The study includes electrical measurements (d.c. resistivity, dielectric constant and the spontaneous thermal current), differential thermal analysis (DTA) and dilatometric thermal analysis in the temperature range −60 °C up to 30°C. The results show a large change in the various measured parameters sensitive to thermal agitation process and to the presence of the bromine ions in the mixed crystal system close to the morphotropic boundary x = 0.5. At this boundary the temperature region of the ordered phase extended by about 28°C. The transformation enthalpy was reduced in such case to 41.3 cal/mol. According to the different experimental data of the system NH4BrxCl1‐x, a phase diagram was proposed. This phase diagram predicted that the order‐disorder phase transition point changed widely according to the value of x and reached −2°C when the mixed crystal system contained 50% of Br− ions.
Identification of Single‐Particle Configurations at Very High Spin in Some Rare‐Earth Nuclei
Authors: Mansour N. , Bayomy T. , Awwad Z.
Published: May 2007

The nuclear behaviour at high angular momenta is studied by γ‐rays emitted in (HI, Xn) reaction. The study of very‐high spin states in 153Ho via discrete‐line γ‐ray spectroscopy and a comparison between the partial decay schemes of 153Ho and the neighbouring 152Dy and 154Er nuclei are discussed in the context of the high spin structure. Second, we present comments on some phenomena observed at high spin states in 153Ho and 152Dy nuclei.
A Model of Resonance Scattering on Curved Quantum Wires
Authors: Exner Pavel
Published: May 2007

A model of electron motion in a curved quantum wire of a finite length 2D attached to a pair of macroscopic electrodes is studied. Regarding the problem as a two‐dimensional one, we model the electrodes as halfplanes and the quantum wire as a line segment joining them; it supports a potential which is a combination of a constant transversal‐mode energy and an attractive curvature‐induced term. We show that the bound states which may be present at an infinite quantum wire turn into resonances and that spectral concentration is valid as D → ∞.
Die philosophische Potenz der Physik
Authors: Schöpf Hans‐Georg
Published: May 2007

Ansprache gehalten zu Ehren von Hans‐Jürgen Treders 60. Geburtstag.
Die Physik am Ende des 18. Jahrhunderts und Lazare Carnot
Authors: Giessmann Ernst‐J.
Published: May 2007

Es ist kein Zufall, daß vor 200 Jahren solche Ereignisse zusammentrafen, wie die Herausbildung der klassischen Physik im modernen Sinne, die Einführung des metrischen Systems und die Gründung der Annalen. Die Doppelrevolution, die bürgerliche und industrielle Revolution, bestimmten auch die Entwicklung der Naturwissenschaften nachhaltig. L. Carnot wirkte für diesen Umbruch.
Friedrich Möglich ‐ sein Beitrag zum Aufbau der Physik in der DDR. Friedrich Möglich ‐ langjähriger Mitherausgeber und Chefredakteur der „Annalen der Physik”︁
Authors: Rompe Robert
Published: May 2007

Friedrich Möglich, ein Schüler von Max von Laue und Erwin Schrödinger, übernahm 1947 die Chefredaktion der „Annalen der Physik”︁.
Moderne Entwicklung der NMR (Nuclear Magnetic Resonance)
Authors: Lösche Artur
Published: May 2007

Die NMR‐Spektroskopie kann sich altersmäßig nicht mit den Annalen der Physik messen; sie entstand vor rd. 45 Jahren. Ihre Entwicklung wurde und wird durch unterschiedliche Erfahrungen, Erkenntnisse und Techniken bestimmt; sie zeigt, daß auch heute noch die Fortschritte von Spezialgebieten Impulse aus weiten Bereichen der Physik, der Naturwissenschaften und Technik beziehen. In entsprechender Weise machen Spezialzeitschriften das Erscheinen allgemeiner Fachzeitschriften nicht überflüssig. Diese Zusammenhänge sollen an einigen Beispielen der NMR demonstriert werden.
Quantum Measurement and Dynamics
Authors: Grabowski Marian
Published: May 2007

We discuss the question of dynamics in the scheme of the quantum measurement process. Especially we consider the form of the Hamiltonians describing the interaction between the observed system and the apparatus. The problem of their spectra is treated.
Study of Electromagnetic Properties of Nuclei and Structural Changes at High Spins in Yb Isotopes
Authors: Mansour N. , Awwad Z. , Bayomy T. , Diab A.
Published: May 2007

High‐spin states of nuclei, populated by heavy‐ion reactions, are of interest because they reveal changes in the structur of nuclei under stress. In the first part much of our insight into the structure of high‐spin states is being provided by electromagnetic strength functions. In the second part, the level scheme of 158Yb has been extended to I = 37 by using the 98Mo (64Ni, 4n) reaction, and the backbending phenomena in Yb isotopes has been discussed.
Zur Quanten‐Struktur der Meßkörper
Authors: Rompe R. , Treder H.‐J.
Published: May 2007

„Planckionen”︁ sind die größten Elementarteilchen und die kleinsten klassischen Meßkörper.
Baryon‐Baryon Interaction in the Strangeness −1 and −2 Sector in the Non‐relativistic Quark Cluster Model
Authors: Faessler Amand , Straub Ulrich
Published: May 2007

The non‐relativistic quark cluster model is used to describe the baryon‐baryon interaction in the strangeness −1 sector (ΛN, ΣN system) and in the strangeness −2 sector (H‐dibaryon). The calculation in the strangeness −1 sector shows first of all that the cluster model can be successfully extended from the nucleon‐nucleon interaction to the hyperon‐nucleon interaction. In addition this calculation demonstrates at the same time the quality of the quark cluster model. The potentials consist of the one‐gluon exchange and the pseudoscalar‐meson exchange (both containing central and tensor parts), a phenomenological confinement plus an additional central phenomenological σ‐meson exchange. Adjusting one free parameter a very good fit of the experimental hyperon‐nucleon cross sections is achieved. In the second step this model is extended to the strangeness −2 sector. Here the H‐dibaryon is calculated, which is the most promising candidate for a bound six‐quark state. The H‐dibaryon is a linear combination of the three states Λ Λ, ΘN and ΣΣ. Performing the full coupled channel scattering and bound state calculation we predict the H‐dibaryon to be bound. We find a binding energy of (−15 ± 5) MeV below the ΛΛ threshold, i.e. the mass of the H‐dibaryon is predicted to be around 2216 MeV.
Ein Beitrag zur frühen Diskussion um den Äther und die Einsteinsche Relativitätstheorie
Authors: Schröder W.
Published: May 2007

„Wozu nun Geschichte der Physik…︁ Wir hoffen also, die Physik selbst besser zu verstehen, wenn wir ihre Entwicklung kennen. Wir erhoffen auch ein schärferes Augenmaß für ihre gegenwärtig ungelösten Probleme zu erlangen.”︁ (Friedrich Hund 1978)

Die Ätherfrage bildete mit dem Aufkommen der Einsteinschen Resultate ein zentrales Problem für die Physiker (u. a. Lorentz, Drude, Minkowski, Wiechert u.a.). Am Beispiel einer bislang unveröffentlichten Arbeit von Wiechert wird dieses Problem, das zugleich auch für die Rezeption der Einsteinschen Studien wichtig ist, behandelt. Es zeigt sich, daß die „Ablösung”︁ der Äthervorstellung einen geraumen Zeitraum beanspruchte und wesentlich mehr darstellte, als nur den Bruch mit den „klassischen Vorstellungen”︁.
Why are Most Nuclei Prolate?
Authors: Zickendraht W.
Published: May 2007

After seperating collective and single particle coordinates the Schrödinger equation of a system of A nucleons has a form related to the conventional unified model, but in contrast to that there are no redundant variables. Working with the transformed Schrödinger equation, using the strong coupling approximation and requiring constant nuclear volume one finds that two thirds of the nuclei should be prolate and that their largest deformations should be about 1.5 times larger than those for oblate nuclei.
Rate Equations for Light‐Induced Drift
Authors: Haverkort J. E. M. , Woerdman J. P.
Published: May 2007

We present a numerical model aiming at a realistic description of light‐induced drift of multilevel atoms in a buffer gas, specializing to case of Na atoms in a noble gas. The model is based on the optical Bloch equations in which the effect of collisions is incorporated by introducing Keilson‐Storer collision kernels. By marking a connection with kinetic theory all adjustable parameters may be fixed.
ESR and Optical Absorption of Ag in a N2 Matrix
Authors: Görlach E. , Rosendahl R. , Klein U. , Stöckmann H.‐J. , Schrimpf A.
Published: May 2007

Ag atoms isolated in N2 matrices were studied by simultaneous observation of optical absorption and electron spin resonance (ESR). In matrices with low Ag/N2 ratios two ESR signals were observed, both of which could be correlated to the well known absorption triplet corresponding to the 5s 2S → 5p 2P resonance transition. One of the two ESR signals disappeared irreversably upon annealing up to 20 K. The stable species is attributed to Ag atoms in a nanocrystalline environment whereas the unstable species corresponds to atoms in the non‐crystalline regions between the crystallites. In higher doped matrices a new Ag spectrum showed up, both in the optical absorption and in the ESR. It is assigned to Ag atoms with near‐by complexes, possibly Ag clusters.
Laser Cooling in the Center‐of‐Mass System: A Proposal for the Creation of a Monoenergetic Atomic Beam
Authors: Haslwanter Th. , Mlynek J.
Published: May 2007

The longitudinal velocity compression of a supersonic atomic beam (mean velocity v0; initial velocity spread Δvi) by light pressure from two counterpropagating laser fields is studied. A Monte‐Carlo simulation shows that the final velocity ratio v0/Δvf can exceed 1000 in a simple and compact experimental setup.
Application of the Multi‐Doorway Continuum Shell Model to the Magnetic Dipole Strength Distribution in 58Ni
Authors: Spangenberger H. , Beck F. , Richter A.
Published: May 2007

The usual continuum shell model is extended so as to include a statistical treatment of multi‐doorway processes. The total configuration space of the nuclear reaction problem is subdivided into the primary doorway states which are coupled by the initial excitation to the nuclear ground state and the secondary doorway states which represent the complicated nature of multi‐step reactions. The latter are evaluated within the exciton model which gives the coupling widths between the various finestructure subspaces. This coupling is determined by a statistical factor related to the exciton model and a dynamical factor given by the interaction matrix elements of the interacting excitons. The whole structure defines the multi‐doorway continuum shell model. In this work it is applied to the highly fragmented magnetic dipole strength in 58Ni observed in high resolution electron scattering.
Messen, Kalibrieren, Eichen in der Radiologie: Prinzipien und Praxis
Authors: Wagner Siegfried R.
Published: May 2007

Nach einleitender Erläuterung der unterschiedlichen Meßbedingungen in der Strahlentherapie und im Strahlenschutz werden die metrologischen Probleme am Beispiel der Größenkategorie Äquivalentdosis diskutiert. Als spezielle Größen werden „effektive Äquivalentdosis”︁ und „Umgebungs‐Äquivalentdosis”︁ eingeführt. Es wird gezeigt, wie „richtiges”︁ Messen durch ein konsistentes System von Bauartanforderungen an Meßgeräte, durch Kalibrieren und durch Eichen gewährleistet werden kann. Die Bedeutung von Meßunsicherheiten und Fehlergrenzen wird erläutert und ihre Auswirkung auf die Interpretation von Meßergebnissen behandelt.
Study of Radiative Deexcitation Processes in the Muonic Helium(4) Ion at 14 and 40 Atmospheres
Authors: Rosenkranz J. , Arnold K.‐P. , Gladisch M. , Hofmann J. , Mundinger H.‐J. , Orth H. , zu Putlitz G. , Stickel M. , Schäfer W. , Schwarz W. , Hughes V. W.
Published: May 2007

To search for a long living 2S1/2 state in the muonic helium ion at helium gas pressures of 14 and 40 atmospheres, radiative muon transitions were registered in a time resolved mode using sodium iodide crystals. Special care was taken to avoid gas impurities which are known to reduce the 2s lifetime significantly. In addition to the prompt photons of the K‐series, a delayed component was detected. The lifetime and yield of this component agree with theoretical values for ions not perturbed by the surrounding medium. However, test measurements carried out with other target gases clearly demonstrate that practically all of the delayed events observed in pure helium are not caused by the radiative decay of a longliving 2s state.
Theoretical Experiments on Multiphoton‐Assisted Electron‐Atom Scattering
Authors: Grobe R. , Moore C. I. , Su Q. , Greenwood W. G. , Eberly J. H.
Published: May 2007

We present the results of numerical experiments in which electron‐atom scattering occurs in the presence of a strong laser field. We compare our results for both forward and backward scattering with previous theoretical work in both strong‐field and weak‐field regimes.
Flugzeit‐Massenspektrometer mit gitterfreien Ionenspiegeln und Elektronenstoß‐Ionenquellen
Authors: Wollnik H. , Grüner U. , Li G.
Published: May 2007

Es werden Flugzeit‐Massenspektrometer mit Massenauflösungsvermögen von m/Δm ≈︁ 103 bis ≈︁ 104 beschrieben, in denen Ionen untersucht werden können, die durch Elektronenstoß gebildet worden sind. Wichtige Teile solch eines Massenspektrometers sind eine Ionenquelle, in der die zwischen den Extraktionspulsen gebildeten Ionen effektiv gespeichert werden, sowie ein gitterfreier Ionenspiegel, der die Ionenflugzeit unabhängig von Energieabweichungen macht und der gute laterale Fokussierungseigenschaften besitzt.
Study of the Effect of Iron Loaded with B4C on the Total Gamma Doses Emitted from Laminated Shield
Authors: Makarious A. S. , Maayouf R. M. A. , Megahid R. M. , El‐Sayed Abdo A.
Published: May 2007

In this work a comparative study of the effect of iron loaded with B4C on the suppression of gamma‐rays in a laminated shield of water, iron and either ordinary or limenite concrete have been carried out. It was found that B4C loaded with iron has a remarkable effect on the suppression of gamma doses all through the laminated shield. The suppression is more pronounced in the concrete layer. It was also found that the decrease of gamma doses in ilmenite concrete is ∼ 1.7 that one for ordinary concrete.
Über mögliche Grenzen einer Gravitationstheorie
Authors: de Zela Francisco
Published: May 2007

Diese Arbeit versucht, eine Antwort auf die Frage zu geben, wieso Gravitationsphänomene gerade durch eine Theorie beschrieben werden, in welcher eine Riemannsche Metrik vorkommt, die den Einsteinschen Gleichungen genügen muß. Als Antwort wird nach einer Verbindungslinie gesucht, welche vom Maupertuisschen Prinzip ausgehend in den Einsteinschen Gleichungen endet. Der metrische Tensor wird zunächst rein formal eingeführt, als richtungsabhängige Finslersche Metrik, und dann, als Folge der Invarianz gegenüber punktalen Lorentz‐Drehungen, auf den Riemannschen Fall zurückgeführt.

Die Konstruktion legt den Schluß nahe, daß der Gravitationsbegriff bei atomaren Dimensionen sinnlos werden kann, wegen der zentralen Rolle, welche die Teilchenbewegung im Ganzen spielt.
White and Grey Holes in Higher‐Dimensional Representation of Extended Space‐Time Manifolds of General Relativity
Authors: Trofimenko A. P. , Gurin V. S.
Published: May 2007

The extended Kerr‐Newman manifold is analysed including subluminal and superluminal space‐time regions. For the united description of different regions separated by horizons complex space‐time is introduced. In such manifold various anticollapsing objects (white and grey holes) are considered.
Polarization Bistability due to Optical Feedback
Authors: Belkner P. , Schütte F.‐J.
Published: May 2007

An optical ring cavity filled with an isotropic medium is driven externally. Two waves of the same frequency but of different polarization are coupled nonlinearly by a Kerr type interaction. It is theoretically shown that the symmetry of the linear polarized input field may be broken spontaneously. Beyond an intensity threshold the output field gets elliptic polarization. Right and left elliptic states are stable. The system shows polarization bistability.
Radiative Corrections to Non‐Abelian Gauge Theory in Homogeneous Self‐Dual Backgrounds
Authors: Eberlein C. , Kaiser H. J. , Wieczorek E.
Published: May 2007

We study the Euclidean version of non‐Abelian gauge theories in homogeneous background fields with due regard of negative and zero modes of the gauge field kernel. For general gauge group and general background but without external currents we prove a relation between the propagators belonging to different gauge fixings. Specializing to a self‐dual homogeneous background we derive nonperturbatively the propagators. Next we calculate the matter field contribution to the renormalized polarization tensor using a modified dimensional regularization scheme. We prove the validity of a modified Ward identity.
Relaxation of Translational Energy in Binary Mixtures of Dilute Gases Composed of Hard Spheres
Authors: Cukrowski A. S. , Fritzsche S.
Published: May 2007

Analytical expressions for the relaxation time τ necessary for the equilibration of translational energies of components in binary mixtures of dilute gases composed of hard spheres are derived. An expression for the collision number Z describing the mean number of collisions of one particle during the relaxation time is also given. The derivation has been performed for the very beginning of the relaxation and we choose the initial translational energy of the sort which is in excess to be equal to zero. Computer results obtained by a direct simulation method of solution of the Boltzmann equation do not only confirm these results but also show them to be valid for a relatively long part of the equilibration.
Das singuläre Modell der über der Oberfläche von Kryodielektrikas lokalisierten Elektronenzustände
Authors: Dorofeyev O. F. , Lysov B. A. , Pavlova O. S. , Ternov I. M.
Published: May 2007

Wir schlagen ein neues Modell zur Beschreibung der in der Nähe der Oberfläche von Kryodielektrika lokalisierten Elektronenzustände vor. Dabei wird die Nichteindeutigkeit der selbstadjungierten Erweiterung des Hamilton‐Operators der elektrostatischen Bildkräfte an der flachen Grenze Dielektrikum‐Vakuum benutzt. Im Unterschied zum bekannten Modell von Grimes enthält das von uns vorgeschlagene Modell nur einen einzigen phänomenologischen Parameter, den Vermischungswinkel. Es zeigt sich, daß die entsprechende Wahl des Vermischungswinkels es erlaubt, die spektroskopischen Daten von elektrischen Dipolübergängen zwischen den Einteilchen‐Elektronenzuständen, die über der Oberfläche flüssigen 4He und 3He sowie festen Wasserstoffe lokalisiert sind, vollständig zu beschreiben.
Unitary Information Ether and its Possible Applications
Authors: Horodecki R.
Published: May 2007

The idea of information ether as the unitary information field is developed. It rests on the assumption that the notion of information is a fundamental category in the description of reality and that it can be defined independently from the notion of probability itself. It is shown that the information ether provides a deterministic background for the nonlinear wave hypothesis and quantum cybernetics.
On a Lorentz Non‐Invariant Generalization of the Dirac Equation
Authors: Bleyer Ulrich
Published: May 2007

A generalized Dirac equation is presented as a model theory of disturbed Lorentz invariance. The physical properties of this model and experimental consequences are discussed. A program is described how such Lorentz noninvariant equations may be produced by cosmological induction of local causal structure.
On the Locality of the No Hair Conjecture and the Measure of the Universe
Authors: Pacher Tibor , Stein‐Schabes Jaime A.
Published: May 2007

We reanalize the recently proposed proof by Jensen and Stein‐Schabes [1] of the No Hair Theorem for inhomogeneous spacetimes, putting a special emphasis on the asymptotic behaviour of the shear and curvature. We conclude that the theorem only holds locally and estimate the minimum size a region should be in order for it to inflate. We discuss in some detail the assumptions used in the theorem. In the last section we speculate about the possible measure of the set of spacetimes that would undergo inflation.
Charged Black Holes and Multidimensional Gravity
Authors: Bronnikov K. A.
Published: May 2007

A multidimensional generalization of the Reissner‐Nordström solution of general relativity is obtained for the case of n Ricci‐flat internal spaces. A two‐parameter family of black‐hole solutions for an arbitrary dimensionality D is selected. Nontrivial black holes with D > 4 are shown to exist only with a nonzero electric charge. Observational consequences are discussed, in particular, a violation of Coulomb's law.