bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diurnal and Eleven‐ Year Variations of Neutron Component of Cosmic Rays
Authors: Bishara A. A. , Azzam A. A. , Darwish A. A. 
Published: May 2007

AbstractCosmic ray ground observations are used together with the method of coupling coefficients to determine, by spectrographic method, the features of the variational primary energy spectrum of diurnal and eleven‐year variations of neutron component of cosmic rays. It is found that the variational energy spectrum responsible for both types of variations can be best described by a constant spectrum up to an upper effective rigidity boundary. The upper cut‐off effective rigidity boundary for the variational energy spectrum of diurnal variation was found to change from 105 GV at maximum solar activity to 15.85 GV at minimum solar activity. For Eleven‐year variation, Rmax was found to have a value of about 20 GV which changes slighly with solar activity due to the change of the coupling coefficients with solar activity.
Dynamical Behaviour of the Mass Asymmetry Mass Parameter in Nuclear Fission
Authors: Osman Ahmed , Zaky M. , Saleh S. A. 
Published: May 2007

AbstractThe theory of nuclear fission is reconsidered. We study the behaviour of the mass parameter as a dynamical quantity of the mass asymmetry. The dependence of the mass asymmetry mass parameter is studied as a function of the five collective coordinates. These parameters are reconsidered by including the temperature to show the temperature dependence of the mass parameter. The cranking model is used in developing all the mathematical and theoretical expressions. Numerical calculations of the obtained analytical expressions are carried out for the two fissioning nuclei 236U and 238U. The mass asymmetry mass parameters are calculated including the temperature as a function of the different five collective coordinates. The present study shows that the values of this mass asymmetry mass parameters are stable against the change of the temperature for temperature values greater than 1 MeV for all the different five collective coordinates.
Nuclear Shape Transitions and Some Properties of Aligned‐Particle Configurations at Very High Spin in Some Rare‐Earth Nuclei
Authors: Mansour N. , Bayomy T. , Awwad Z. 
Published: May 2007

AbstractWe will present results on an collective ΔI = 2 ground band level sequence in the spherical six‐valence‐particle nucleus 152Dy and the variation of shapes for nuclei in the N = 88 to 92 transitional region. Finally, we will present results for some even‐even nuclei without any backbending behaviour, showed a clear backbending in the diagram of 2𝒥/ℏ2 versus (ℏω)2.
Infinite‐dimensional Symmetries
Authors: Doebner H. D. , Tolar J. 
Published: May 2007

AbstractWe report on infinite‐dimensional symmetries connected with our approach to quantization on manifolds. Our method allows to quantize the class of classical systems admitting localization on configuration spaces which are finite‐dimensional differentiable manifolds. We observe that the quantum kinematical observables on the configuration manifold M realize a representation of an infinite‐dimensional Lie algebra ℒ︁ = C∞(M, ℝ) ∉ 𝒳 (M), where 𝒳 (M) is the Lie algebra of smooth vector fields on M. In particular, we construct representations of ℒ︁ in the Hilbert spaces of sections of ℂk‐bundles over M and call them k‐quantum Borel kinematics. For the special class of “type 0” k‐quantum Borel kinematics, which we completely classify, the criteria of irreducibility and unitary equivalence are stated. As an illustration, we consider quantizations on a circle M = S1, and present the associated representations of the infinite‐dimensional Virasoro algebra (without the central term).
Calculation of Coherence Artefacts in Phase‐Conjugated Signals
Authors: Wilhelmi Bernd 
Published: May 2007

AbstractThe intensity of the phase‐conjugated signal in degenerate fourwave mixing depends on the delay of the signal wave with respect to the pump waves if all waves originate from one and the same primary source. The coherence peak, which appears at zero delay, has been calculated for an ensemble of two‐level absorbers in the rate equation approximation. The height of the coherence peak depends on the strength of the frequency fluctuations of the primary light source and on the relaxation time of the absorber molecules. The width of the coherence peak is given by the correlation time of the frequency fluctuations.
On a Class of Kinetic Equations for Particles with Discrete Velocities
Authors: Crell Bernd 
Published: May 2007

AbstractWe investigate a class of kinetic equations with quadratic nonlinearity describing particles with discrete velocities, distinguished by the existence of some linear conservation quantities and the property that in the homogeneous case every solution (in the state space) is also a solution of a certain master equation. Examples will be discussed.
Neue elektrische Quantenmaße mit weltweiter Gültigkeit ab 01. 01. 1990
Authors: Kose Volkmar 
Published: May 2007

AbstractWeltweit gelten ab 01. 01. 1990 neue einheitliche Quantenmaße für die Bewahrung und Weitergabe der Einheiten für die elektrische Spannung Volt und für den elektrischen Widerstand Ohm. Damit haben das Josephson‐Spannungsnormal und das von‐Klitzing‐Normal endgültig die höchstwertigen Normale der klassischen Physik abgelöst. Der Aufsatz stellt die neue Situation vor und diskutiert die Vorzüge bzw. Nachteile der Quantenmaße, ihren Zusammenhang mit Fundamentalkonstanten und dem internationalen Einheitensystem.
Transformation of an Atomic Alignment into an Orientation in a Discharge
Authors: Elbel M. , Simon M. , Strauss Th. 
Published: May 2007

AbstractIt is shown that an atomic state aligned by optical pumping with linearly polarized laser light, is partly transformed into an oriented state by the action of an electric field (Stark effect) or by collisional interaction with electrons. The outcome of the experiment suggests that the influence of the electrons prevails.
A Heuristic Analysis of Quantum Noise Quenching in the Two‐Photon Correlated Emission Laser
Authors: Benkert Claus , Schleich Wolfgang , Scully Marlan O. 
Published: May 2007

AbstractWe demonstrate how the two‐photon correlated emission laser (CEL) can be understood from a simple physical picture in a quasirigorous fashion. We use semiclassical arguments to derive correct expressions for the phase and amplitude diffusion in a simple way. We then illustrate how noise suppression is achieved in the two‐photon CEL.
Free energy and correlation lengths of quantum chains related to restricted solid‐on‐solid lattice models
Authors: Klümper A. 
Published: May 2007

AbstractAn approach is presented for calculating the free energy as well as the correlation lengths of integrable quantum chains at arbitrary finite temperatures. The method is applied to critical Hamiltonians related to restricted solid‐on‐olid models comprising the hierarchy by Andrews, Baxter and Forrester, and generalizations hereof by the fusion procedure. The derived non‐linear integral equations can be studied analytically in the low‐temperature and high‐temperature limits. The central charges and all primary conformal weights are obtained for the generalized minimal unitary series of conformal field theory and the ZN parafermion theories. Thus an extension of the thermodynamic Bethe Ansatz is realized which recently has been speculated on in the literature.
Self‐localized single‐anharmonic vibrational modes in two‐dimensional lattices
Authors: Fischer Fred 
Published: May 2007

AbstractMany stationary forms of self‐localized modes exist in a simple square and hexagonal lattice. They consist of a certain number of an elementary self‐localized anharmonic mode (SLAM). This has several shapes depending on the uniform power of the nearest‐neighbour interaction. By comparing SLAMs of the same vibrational frequency a binding energy can be derived for each stationary aggregated SLAM. Also infinite chains and whole lattices of elementary SLAMs are obtained. They have to be distinguished from standing waves of single‐anharmonic phonons.
Electronic properties and superconductivity of amorphous Si1‐xAux alloys near the metal‐insulator transition
Authors: Fischer J. , v. Löhneysen H. 
Published: May 2007

AbstractWe report on specific‐heat and resistivity measurements on quench‐condensed Si1‐xAux films for 0.11 ⩽ x 0.36 in the temperature range 0.35 K ⩽ T ⩽ 6 K. A distinct increase of the specificheat derived electronic density of states at the Fermi level is observed at xb ≈ 0.2, i.e., in the vicinity of the metal‐insulator transition occurring for our samples at xc = 0.16. This suggests a different type of bonding between Au and Si for x < xb and x > xb. While resistive transitions to superconductivity are observed for x⩾0.21, the absence of a specific‐heat anomaly at the transition points to filamentary superconductivity except for × = 0.35 where a sizable anomaly is seen. The difference in various electronic properties between differently prepared samples of these metastable alloys, in particular the influence of different preparation and annealing temperatures is emphasized. It is suggested that these differences are caused by incipient phase separation in the room‐temperature prepared samples.
Spin‐wave renormalization by mobile holes in a two‐dimensional quantum antiferromagnet
Authors: Krier Georges , Meissner Günther 
Published: May 2007

AbstractThe coupling of antiferromagnetic spin excitations and propagating holes has been studied theoretically on a square lattice in order to investigate the dependence of antiferromagnetic order on hole doping, being of relevance, e.g., for the Cu–3 d9 system in antiferromagnetic CuO2‐planes of high‐Tc superconductors. An effective Hamiltonian has been used, which results from a 2D Hubbard model (hopping integral t) with holes and with strong on‐site Coulomb repulsion U. Bare antiferromagnetic excitations and holes with energies of the same order of magnitude t2/U are interacting via a coupling term being proportional to t and allowing holes to hop by emitting and absorbing spinwaves. In terms of a self‐consistent one‐loop approximation the renormalization of the spectral function both of holes and antiferromagnetic spin excitations are calculated.
Scanning tunneling microscopy of RF oscillating surfaces
Authors: Chilla E. , Rohrbeck W. , Fröhlich H.‐J. , Koch R. , Rieder K. H. 
Published: May 2007

AbstractAmplitude and phase of high frequency surface acoustic wave (SAW) fields are investigated by a novel scanning tunneling microscopy technique. The gap voltage is modulated at a slightly detuned high frequency. Due to the nonlinearity of the tunneling process a frequency mixing appears. For scanned areas with dimensions much smaller than the wavelength of the SAW a remarkable local variation of amplitude and phase of the tunneling current at the difference frequency is observed. Depending on the local morphology different components of the particle displacement vector are detected. Model calculations of amplitude and phase images are presented for a real topography.
Response of a Bloch oscillator to a THz‐field
Authors: Ignatov A. A. , Schomburg E. , Renk K. F. , Schatz W. , Palmier J. F. , Mollot F. 
Published: May 2007

AbstractIn this paper we report on the observation of response of a Bloch oscillator at room temperature to a THz‐field of a frequency larger than the Bloch frequency. The oscillator consisted of a semiconductor superlattice structure, with an applied dc voltage giving rise to a dc electron drift current. Submitting the oscillator to a field at a frequency of 3.3 THz caused a sizeable reduction of the current; the THz‐field was generated by use of intense THz‐radiation pulses focused on an antenna coupled to the superlattice. We attribute the THz‐field induced reduction of the current to a frequency modulation of the Bloch oscillations of electrons at the frequency of the THz‐field, leading to reduction of the electron drift velocity and, consequently, of the current.
Variational approach to spin fluctuations in the Hubbard model
Authors: Dahm S. , Brenig W. 
Published: May 2007

AbstractWe study a one parameter variational wave function to improve the spin density wave ground state of the Hubbard model by inclusion of quantum spin fluctuations. Using a perturbative approach and novel lattice summation techniques we present analytical as well as numerical results for the correlation energies and the staggered magnetizations in one and two dimensions. We find ground state energies which are satisfyingly close to known exact results and are significantly lower than those of existing Gutzwiller and numerical treatments.
Traffic flow models with ‘slow‐to‐start’ rules
Authors: Schadschneider Andreas , Schreckenberg Michael 
Published: May 2007

AbstractWe investigate two models for traffic flow with modified acceleration (‘slow‐to‐start’) rules. Even in the simplest case vmax = 1 these rules break the ‘particle‐hole’ symmetry of the model. We determine the fundamental diagram (flow‐density relationship) using the so‐called car‐oriented mean‐field approach (COMF) which yields the exact solution of the basic model with vmax = 1. Here we find that this is no longer true for the models with modified acceleration rules, but the results are still in good agreement with simulations. We also compare the effects of the two different slow‐to‐start rules and discuss their relevance for real traffic. In addition, in one of these models we find a new phase transition to a completely jammed state.
The liquid crystalline properties of some ferrocene‐containing Schiff bases
Authors: Cârlescu Irina , Scutaru Ana Maria , Apreutesei Daniela , Alupei Valentina , Scutaru Dan 
Published: May 2007

AbstractThe synthesis and characterization of new ferrocene‐containing mesomorphous compounds is described. In order to induce mesogenic behavior, the structure of the substituent was systematically modified. Derivatives with no more than two rings in the core did not exhibit liquid crystalline properties. The synthesized products were characterized using NMR, IR and mass spectroscopy, DSC and polarized optical microscopy. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation and properties of poly(ethylene terephthalate)/ATO nanocomposites
Authors: Chen Xiaolei , Li Chunzhong , Shao Wei , He Junqing 
Published: May 2007

AbstractAntimony doped tin oxide (ATO) nanoparticles modified poly(ethylene terephthalate) (PET) composites used for manufacturing antistatic PET fiber were synthesized by in situ polymerization. The crystallization and multiple melting behavior of the nanocomposites were systemically investigated by means of Differential Scanning Calorimeter (DSC), Fourier Transform Infrared (FTIR), X‐ray Diffraction (XRD) techniques. The degree of crystallinity in nanocomposites increased with increasing ATO content. Smaller and more incomplete crystals are presented in the crystalline regions of the nanocomposites with increasing the content of ATO, which could be attributed to heterogeneous nucleation effects of ATO nanoparticles. Dynamic Mechanical Analysis (DMA) measurements showed that the storage moduli of the nanocomposites increased with increasing the content of ATO, due to formation of immobilized layer between polymer and filler. The interactions between ATO and PET molecules result in high tan δ for the PET/ATO nanocomposites. Percolation threshold of PET/ATO hybrid fibers prepared by the nanocomposites at room temperature was as low as 1.05 wt %, much lower than that of the composites filled with conventional conductive particles. Adding ATO nanoparticles obviously improves the conductivity of PET. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Microfoams based on castor oil polyurethanes and vegetable fibers
Authors: Aranguren Mirta I. , Rácz Ilona , Marcovich Norma E. 
Published: May 2007

AbstractThis work was focused on the production and characterization of microcellular polyurethane (PU) composites reinforced with pine wood‐fibers or with hemp, which can be applied to the manufacture of car interior panels, or acoustic insulation panels for the construction industry. The polymers selected for the study were crosslinked PUs, synthesized from a castor oil‐based polyol, with the formulations adjusted to obtain different foaming levels. Microfoamed composites with preferential orientation were prepared from long hemp fibers. Also, samples with random arrangement of short hemp and wood fibers were obtained. The morphology of the composites was analyzed by scanning electron microscopy. The mechanical performance of the reinforced foams was studied through three point bending and dynamic mechanical tests. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
(Re)presenting experience: a comparison of Australian Aboriginal children's sand play in two settings
Authors: Eickelkamp Ute 
Published: May 2007

AbstractThis paper examines how Australian Aboriginal children present and re‐present experience in their symbolic play. Based on anthropological field research in one location and therapeutic work in another, it reports from a psychodynamic perspective how the Indigenous children create meaning on the personal and social level in two distinctive play forms. These are a traditional sand story game played by Anangu Pitjantjatjara girls in a remote Western Desert community in Central Australia, and the European sand play therapy that was introduced as part of an intervention program in a Tiwi Islands community off the northern coast. In phenomenological terms, both techniques draw on the symbolizing activity of the lived body (Schilder, 1950, 1951; Merleau‐Ponty, 1961; Scheler, 1973) or, in the language of organismic‐developmental theory, physiognomizing processes (Werner and Kaplan, 1984). These processes are seen to rest on the primary human capacity for imagination (Castoriadis, 1987). However, the schematizing activity that creates a meaningful relationship between symbol and referent (Werner and Kaplan, 1984) is specific to each play form. Set up retrospectively as a comparison, the discussion leads to the observation that the self‐directed play in the natural social setting is of a higher symbolic order (re‐presentational) than the externally induced play in the artificial social setting that indicates spontaneous linkages between symbol and referent (presentational). It is suggested that this raises certain questions about the potentially therapeutic effect of children's symbolic play. Copyright © 2007 John Wiley & Sons, Ltd.
Intradiol pathway of para‐cresol conversion by Rhodococcus opacus 1CP
Authors: Kolomytseva Marina P. , Baskunov Boris P. , Golovleva Ludmila Alexeevna 
Published: May 2007

AbstractThe growth of Rhodococcus opacus 1CP in medium with different concentrations of p‐cresol as the sole source of carbon and energy was studied. It was shown that the optimal concentration of p‐cresol was 600 mg/L. The ability of this strain to transform practically all amounts of p‐cresol to 4‐methylcatechol followed by its utilization through ortho‐pathway was shown. New enzymes (4‐methylcatechol 1,2‐dioxygenase, catechol 1,2‐dioxygenase, and methylmuconate cycloisomerase) were purified to homogeneity and characterized. Based on the data obtained on p‐cresol degradation, formation of intermediates, and the enzymes participating in this pathway, we suggest an ortho‐pathway of p‐cresol degradation by R. opacus 1CP through 4‐methylcatechol and 3‐methyl‐cis, cis‐muconate.
Constructing insanity: jurors' prototypes, attitudes, and legal decision‐making
Authors: Louden Jennifer Eno , Skeem Jennifer L 
Published: May 2007

AbstractResearch consistently indicates that jurors' intuitive prototypes of insanity and case‐relevant attitudes shape their verdicts more strongly than legal definitions of insanity. Based on a sample of 113 prospective jurors, this study was designed to (a) assess the extent to which three prototypes of insanity held by jurors in a past study generalize to a sample of jurors in another state and (b) determine the relative influence of attitudes toward the insanity defense and prototypes of insanity on jurors' case judgments across four insanity case vignettes. Results suggest that jurors' attitudes toward the insanity defense affected case judgments so strongly (r = .41–.61) that they swamped efforts to assess jurors' prototypes of insanity. Further, jurors' prototypes of insanity offered little incremental utility beyond that of insanity defense attitudes. Implications for identifying biased jurors and potential interventions for bringing jurors' decisions into greater accord with the law are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Zum Problem der optisch aktiven alkaliorganischen Verbindungen (Stereochemische Studien, III)
Authors: Ziegler Karl , Wenz Adolf 
Published: May 2007

AbstractOptisch aktives 2‐Dimethylamino‐9‐methyl‐fluoren wird bei Umwandlung in seine 9‐Lithium‐Verbindung und Rückgewinnung aus dieser inaktiv.
Notiz über 2‐Oxy‐hydrindon‐(1)
Authors: Schöpf Clemens , Kühne Rudolf 
Published: May 2007

AbstractFür die in der Literatur als 2‐Oxy‐hydrindon‐(1) beschriebene Verbindung wird durch Überführung in Isocumarin diese Konstitution einwandfrei nachgewiesen.
Über die Konstitution der Isostrychninsäure (III. Mitteil. über Strychnos‐Alkaloide)
Authors: Boit Hans‐G. 
Published: May 2007

AbstractIsostrychninsäure läßt sich über Bromdesoxy‐isostrychnin in Isostrychnin‐I, Nb‐Methyl‐isopseudostrychninsäure analog in N‐Methylisopseudostrychnin überführen. Isotetrahydrostrychnin (Tetrahydro‐isostrychninsäurelactam) geht unter verschiedenen Bedingungen durch Wasserabspaltung in Desoxy‐dihydro‐isostrychnin über, während das aus ihm durch elektrolytische Reduktion erhältliche Isotetrahydrostrychnidin keine Tendenz zur Wasserabspaltung zeigt. Unter Zuhilfenahme von Modellbetrachtungen wird gefolgert, Daß Isostrychninsäure mit Strychninsäure stereoisomer ist und sich von ihr nur durch Vertauschung des Wasserstoffatoms und des Essigsäure‐Restes am Kohlenstoffatom 12 unterscheidet. Aus Isobrucinsäure‐hydrazid wird durch Curtiusschen Abbau das entsprechende Na‐Nitroso‐methylurethan erhalten.
Umsetzungsprodukte von Chinonen und anderen Carbonylverbindungen mit Cystein
Authors: Kuhn Richard , Hammer Ingrid 
Published: May 2007

AbstractEs werden 3 Reaktions‐Typen bei der Umsetzung von Chinonen und anderen Carbonylverbindungen mit Cystein festgestellt: 1.) Addition der SH‐Gruppen (von Dehydrierung und Ringschluß begleitet), 2.) Dehydrierung zu Cystin, 3.) Mercaptal‐Bildung.
Autoxydation von Kohlenwasserstoffen, XV. Mitteil.): Zur Isolierung der aus Inden gebildeten Peroxyde
Authors: Hock Heinrich , Depke Fritz 
Published: May 2007

AbstractMit Hilfe der früher für 1.2‐Dialin ausgearbeiteten Fällungsmethode wurden die durch Autoxydation von Inden zuerst entstehenden Peroxyde in Substanz isoliert und physikalisch sowie chemisch gekennzeichnet.
Thiacumarindiol und seine Derivate
Authors: Arndt Fritz , Loewe Lotte , Ayça Ertugrul 
Published: May 2007

Abstract3.4‐Dioxy‐1‐thia‐cumarin reagiert mit Diazomethan überwiegend als solches und nur zu einem kleinen Anteil als Thiachromondiol. Die “reaktionskinetische Abhängigkeit” von der Diazomethan‐Konzentration ist hier sehr deutlich.
Zur Autoxydation sauerstoffaktiver Säuren, XIV. Mitteil.): Autoxydation in alkalischem Medium
Authors: Treibs Wilhelm , Rothe Manfred 
Published: May 2007

AbstractBei der Autoxydation ungesättigter langkettiger Fettsäuren in wäßrig‐alkalischem Medium bei 120–130° finden 2 Konkurrenzreaktionen statt: 1.) Aufspaltung zu Säuren neben den Doppelbindungen oder Doppelbindungssystemen und 2.) Verschiebung isolierter Doppelbindungen nach der Carboxygruppe hin zu sehr sauerstoffbeständigen α,β‐ungesättigten Säuren.