bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combinatorial investigations of interfacial failure
Authors: Crosby Alfred J. , Karim Alamgir , Amis Eric J. 
Published: March 2003

AbstractConventional measurements of interfacial strength focus on a single variable, whereas many variables couple nontrivially and simultaneously to define this property. We present a combinatorial methodology that allows the effects of multivariable environments on interfacial strength to be investigated in a high‐throughput, parallel, and quantitative manner. This technique is largely based on the theory of Johnson, Kendall, and Roberts that quantifies adhesion through the contact and separation of a spherical lens and flat substrate. For our experiments, we fabricated a combinatorial library consisting of a two‐dimensional array of spherical caps and a complementary substrate. The array of spherical caps was brought into contact and subsequently separated from the substrate, whereas the relative displacement and contact area of the individual lenses were recorded. With gradient library‐fabrication methods, two adhesion‐controlling parameters can be continuously varied along the orthogonal axes of the array. In this manner, each lens quantifies the interfacial strength at a unique point in parameter space. We demonstrate this multilens contact‐adhesion test by measuring the effect of temperature and coating thickness on the self‐adhesion of polystyrene thin films. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 883–891, 2003
The periglacial record of Holocene environmental change, subantarctic Marion Island
Authors: Holness S. D. 
Published: March 2003

AbstractThis paper examines the evidence for cold‐climate conditions on Marion Island, both present and past, and discusses the palaeoenvironmental implications. Under present conditions frost penetration, except in the highest‐altitude areas, is limited to the upper 0.05–0.3 m of the soil. Relict periglacial features include large stone‐banked lobes and terraces, vegetation‐banked features and blockstreams. It is suggested that these features are the result of deep seasonal frost. Copyright © 2003 John Wiley & Sons, Ltd.
The impact of solar radiation upon rock weathering at low temperature: a laboratory study
Authors: Zhu Li‐ping , Wang Jia‐cheng , Li Bing‐yuan 
Published: March 2003

AbstractThe impact of solar radiation heating upon rock temperatures in a cold environment was investigated by an experimental simulation. Different rock samples, collected from the central part of the Tibet Plateau, were pre‐treated and put in a low‐temperature box. Temperatures in the box changed by a radiation heat source that simulated solar insolation. Results show that the temperature‐increase rate of samples saturated by water is similar to that saturated by salt solution, but the decrease rate of the former is higher than the latter. The temperature rebound derived from the potential heat release of the rock‐interstitial water transition at −4° C occurred more frequently on samples saturated by water than upon those saturated by salt solution. Salt content is a possible agent that inhibits the freeze‐thaw process. Insolation heating induces faster temperature variations on the rock surface than in the interior. This is more closely related to rock mineral composition than to pore size and pore density. This implies that fast temperature variations may lead to the continuous expanding and contraction of the rock minerals. This may result in rock fatigue and may dominate the weathering process. These results, applied to different rocks saturated by water or salt solution, are also supported by measuring changes in ultrasonic‐wave‐transmitting rates. Copyright © 2003 John Wiley & Sons, Ltd.
Quantum measurement and information
Authors: Hradil Z. , Řeháček J. 
Published: March 2003

AbstractThe operationally defined invariant information introduced by Brukner and Zeilinger is related to the problem of estimation of quantum states. It quantifies how the estimated states differ in average from the true states in the sense of Hilbert‐Schmidt norm. This information evaluates the quality of the measurement and data treatment adopted. Its ultimate limitation is given by the trace of inverse of Fisher information matrix.
Stability of quantum spins in a magnetic field
Authors: Burić N. 
Published: March 2003

AbstractContinuous representations of the dynamical $SU(2)$ group, and the corresponding generalized coherent states, are used to conjugate dynamics of a system of quantum spins to that of a classical Hamiltonian system. Stability of the Hamiltonian system obtained are studied, using linear stability analyses and results from the perturbation theory. Quantum evolution of any of the compound‐spins components is described exactly by classical Hamilton's equations. No semiclassical asymptotics in the analyses or explicit time‐dependence has been involved.
Application of the multicomponent Falicov–Kimball model to intermediate‐valence materials: YbInCu4 and EuNi2(Si1–xGex)2
Authors: Freericks J. K. , Zlatić V. 
Published: March 2003

AbstractWe develop a formalism to solve the multicomponent Falicov–Kimball model with dynamical mean‐field theory, allowing for all possible crystal‐field couplings (including spin‐orbit coupling). We apply these techniques to solve models of the intermediate‐valence transition [as seen in YbInCu4 and EuNi2(Si1–xGex)2] in the simple limit of no crystal field or spin‐orbit coupling. We show results for the uniform spin susceptibility, the average localized electron concentration, and transport properties. We also investigate the metamagnetic transition.
Ab initio theory of exchange interactions in itinerant magnets
Authors: Turek I. , Kudrnovský J. , Drchal V. , Bruno P. , Blügel S. 
Published: March 2003

AbstractThe paper reviews an ab initio two‐step procedure to determine thermodynamic properties of itinerant magnets. In the first step, the selfconsistent electronic structure of a system is calculated using the tight‐binding linear muffin‐tin orbital method combined with Green function techniques. In the second step, the parameters of the effective classical Heisenberg Hamiltonian are determined using the magnetic force theorem and they are employed in subsequent evaluation of magnon spectra, the spin‐wave stiffness constants and the Curie/Néel temperatures. Applicability of the developed scheme is illustrated by investigations of selected properties of 3d metals Fe, Co, and Ni, diluted magnetic semiconductors (Ga,Mn)As, and 4f metals Gd and Eu.
Competition between superconductivity and the pseudogap phase in the t–J model
Authors: Zeyher R. , Greco A. 
Published: March 2003

AbstractThe t–J model in the large N limit (N denotes the number of spin components) yields a pseudogap phase in the underdoped region which is related to a d‐wave charge density wave (d‐CDW). We present results for the doping dependence of the superconducting and d‐CDW order parameters as well as for collective excitations in the presence of these two order parameters. We argue that the electronic Raman spectrum with B1g symmetry probes the amplitude fluctuations of the d‐CDW at zero momentum.
Coherent electronic transport through magnetic junction
Authors: Lipiński S. , Bułka B. R. , Babiaczyk W. 
Published: March 2003

AbstractA quantum dot with a single energy level coupled to ferromagnetic electrodes is considered within the slave boson approach. Magnetic polarisation of the leads induces the spin accumulation at the dot. Its maximum occurs in the mixed valence range and decreases to zero in the Kondo regime. We have calculated the conductance for parallel and antiparallel orientations of polarisation of electrodes. Magnetoresistance takes the largest values in the empty state regime, considerably decreases in mixed valence range and reaches the smallest values in the Kondo regime, where in some cases even negative magnetoresistance can occur.
Separation of quadrupole and magnetic mechanismsof 209Bi nuclear spin–lattice relaxation in Bi4Ge3O12
Authors: Morozova E. N. , Gippius A. A. , Khozeev D. F. , Orlov V. G. , Shlikov M. P. , Baenitz M. 
Published: March 2003

AbstractBi4Ge3O12 belongs to the class of complex Bi‐oxides (α‐Bi2O3, Bi3O4Br) which exhibits unusual magnetic properties. Local magnetic fields of about 30 G were revealed in the Bi4Ge3O12 single crystal by 209Bi NQR experiments. In the present paper the nuclear spin–lattice relaxation was studied in the Bi4Ge3O12 single crystal by 209Bi NQR spin–echo technique. The experimental relaxation curves were described by the single effective spin–lattice relaxation time T1. The temperature dependence of 1/T1 was close to Tn law with n = 2.4 – 2.7. The nuclear spin–lattice relaxation in the multi‐level system was theoretically calculated for the case of single‐axial crystalline electric field. Both quadrupole and magnetic mechanisms of relaxation were taken into account. We conclude that the magnetic mechanism contributes noticeably to the spin–lattice relaxation in Bi4Ge3O12 at T ≤ 50 K.
Oxygen‐isotope effect on the magnetic properties of Pr0.7Ca0.3MnO3 under strong pulsed magnetic fields
Authors: Fedorov G. E. , Babushkina N. A. , Inyushkin A. V. , Taldenkov A. N. 
Published: March 2003

AbstractMagnetization and susceptibility measurements have been performed on oxygen‐isotope substituted (16O and 18O) samples of Pr0.7Ca0.3MnO3 under pulsed magnetic fields up to 35 T. Experiments were carried out within the temperature range 78 to 300 K. Magnetic‐field‐induced phase transition into ferromagnetic state has been obtained in both samples at temperatures up to 200 K. Isotope substitution has been proved to have a significant impact on the temperature and field of this transition. Phase diagrams of the samples obtained from magnetization measurements are presented.
Dielectric breakdown strength in magnetic fluids
Authors: Kopčanský P. , Tomčo L. , Marton K. , Koneracká M. , Potočová I. , Timko M. , Jadzyn J. , Czechowski G. 
Published: March 2003

AbstractThe application of an external magnetic field on the magnetic fluids induces needle like structuralization of magnetic particles. The influence of this aggregation of magnetic particles in an external magnetic field H on the magneto‐dielectric behaviour and dielectric breakdown strength of a transformer oil based magnetic fluids was measured. The observed decrease of dielectric breakdown strength (for H = 0 and H ⟂ E vs. distance between electrodes is found to be in agreement with a theory of semi‐classical bond percolation for a non‐linear composite material. In situation when E ‖ H oscillations of dielectric breakdown strength were observed that are associated with a size effect probably.
The ground state for Ising model ±J on the tube
Authors: Błaszyk M. 
Published: March 2003

AbstractThe Ising model with exchange integrals ±J for a square lattice spanned over infinite length tubes of the width of 2, 3, or 4 bonds is considered. The paper gives a short description of a method of linear equations allowing a reduction of a physical problem of determination of e.g. energy, entropy, magnetisation for systems with frozen disorder, to a solution of a system of linear equations. The results for energy, entropy and magnetisation possible for a short presentation are given.
Dynamical CPA theory of magnetism – harmonic approximation
Authors: Kakehashi Y. 
Published: March 2003

AbstractWe have developed the dynamical coherent potential approximation (CPA) to the correlated electron system on the basis of the functional integral method and the harmonic approximation. The theory becomes exact in the high temperature limit, reproduces the results of the second order perturbation theory for small Coulomb interaction, and takes into account the terms to describe the strong correlation limit. The numerical calculations show that the theory describes the Curie–Weiss susceptibility, a large reduction of the Curie temperature due to the dynamical effects, and a many‐body satellite peak as well as a band narrowing in the density of states.
The correlated Kondo‐lattice model
Authors: Kienert J. , Santos C. , Nolting W. 
Published: March 2003

AbstractWe investigate the ferromagnetic Kondo‐lattice model (FKLM) with a correlated conduction band. A moment conserving approach is proposed to determine the electronic self‐energy. Mapping the interaction onto an effective Heisenberg model we calculate the ordering of the localized spin system self‐consistently. Quasiparticle densities of states (QDOS) and the Curie temperature TC are calculated. The band interaction leads to an upper Hubbard peak and modifies the magnetic stability of the FKLM.
Effect of local environment on the magnetic properties of the (Cu1–xCox)2MnSn alloy
Authors: Pugaczowa‐Michalska M. 
Published: March 2003

AbstractThe electronic structure and the ground state properties of the quaternary Heusler alloy (Cu1–xCox)2MnSn have been studied using the TB‐LMTO method. The self‐consistent band structure calculations were performed for experimental lattice parameter. The (Cu1–xCox)2MnSn system has been calculated for the supercell structure and for the following value of the parameter x: 0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875, 1.0. The magnetic properties are in agreement with experimental data. In particular the observed increase of total magnetic moment with concentration of Co is reproduced by our calculations. We present the value of local magnetic moment of the Co and Cu atoms for various possible configurations. The dependence of magnetic moment on the local environment has been studied for all concentrations.
Transparent interface between classical molecular dynamics and first‐principles molecular dynamics
Authors: Du Mao‐Hua , Cheng Hai‐Ping 
Published: March 2003

AbstractA distinctive approach that combines first‐principles Born–Oppenheimer local spin density molecular dynamics (BO‐LSD‐MD) with classical molecular dynamics is formulated, developed, and implemented to study silicon dioxide. Compared with previous hybrid schemes, our Hamiltonian is constructed to optimize the description of local chemistry in the center of the quantum region and mechanical properties at the quantum–classical boundary. With this method, the interface between the quantum and classical regions reflects faithfully the interatomic forces derived from quantum and classical descriptions, respectively. Ground‐state structures obtained using our hybrid approach are compared with those calculated via quantum and classical methods. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Ab initio prediction of the vibrational spectra of the hydrogen‐bonded complexes between CO and HONO2
Authors: Dimitrova Yordanka , Stamboliyska Bistra A. 
Published: March 2003

AbstractThe vibrational characteristics (vibrational frequencies and infrared intensities) for free and complexed CO and HONO2 have been predicted using ab initio calculations at SCF and MP2 levels with different basis sets and B3LYP/6−31G(d,p) calculations. The ab initio calculations show that the complexation between HONO2 and CO leads to two stable structures: CO … HONO2 (1A) and OC … HONO2 (1B). The changes in the vibrational characteristics from free monomers to complexes have been estimated. It was established that the most sensitive to the complexation is the stretching OH vibration. In agreement with the experiment, its vibrational frequency in the complexes is shifted to lower frequency (Δν = −123 cm−1). The magnitude of the wave number shift is indicative of relatively strong hydrogen‐bonded interaction. The ab initio calculations at different levels predict an increase of the infrared intensity of the stretching OH vibration for structure 1A more than five times and for structure 1B more than nine times. The most consistent agreement between the computed values of the frequency shifts for structure 1B and those experimentally observed suggests that this structure is preferred. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Perturbational approach to the electron correlation cusp applied to helium‐like atoms
Authors: Sirbu Ioana , King Harry F. 
Published: March 2003

AbstractA recently proposed perturbational approach to the electron correlation cusp problem Sirbu, I.; King, H. F. J Chem Phys 2002, 117, 6411–6416 is tested in the context of three spherically symmetrical two‐electron systems: helium atom, hydride anion, and a solvable model system. The interelectronic interaction is partitioned into long‐ and short‐range components. The long‐range interaction, lacking the singularities responsible for the electron correlation cusp, is included in the reference Hamiltonian. Accelerated convergence of orbital‐based methods for this smooth reference Hamiltonian is shown by a detailed partial wave analysis. Contracted orbital basis sets constructed from atomic natural orbitals are shown to be significantly better for the new Hamiltonian than standard basis sets of the same size. The short‐range component becomes the perturbation. The low‐order perturbation equations are solved variationally using basis sets of correlated Gaussian geminals. Variational energies and low‐order perturbation wave functions for the model system are shown to be in excellent agreement with highly accurate numerical solutions for that system. Approximations of the reference wave functions, described by fewer basis functions, are tested for use in the perturbation equations and shown to provide significant computational advantages with tolerable loss of accuracy. Lower bounds for the radius of convergence of the resulting perturbation expansions are estimated. The proposed method is capable of achieving sub‐μHartree accuracy for all systems considered here. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Natural and synthetic sialic acid‐containing inhibitors of influenza virus receptor binding
Authors: Matrosovich Mikhail , Klenk Hans‐Dieter 
Published: March 2003

AbstractInfluenza viruses attach to susceptible cells via multivalent interactions of their haemagglutinins with sialyloligosaccharide moieties of cellular glycoconjugates. Soluble macromolecules containing sialic acid from animal sera and mucosal fluids can act as decoy receptors and competitively inhibit virus‐mediated haemagglutination and infection. Although a role for these natural inhibitors in the innate anti‐influenza immunity is still not clear, studies are in progress on the design of synthetic sialic acid‐containing inhibitors of receptor binding which could be used as anti‐influenza drugs. Copyright © 2003 John Wiley & Sons, Ltd.
Structural evidence for common functions and ancestry of the reovirus and adenovirus attachment proteins
Authors: Stehle Thilo , Dermody Terence S. 
Published: March 2003

AbstractThe crystal structure of the reovirus attachment protein, σ1, reveals a fibre‐like structure that is remarkably similar to that of the adenovirus attachment protein, fibre. Both proteins are trimers with head‐and‐tail morphology. They share unique domain structures and functional properties including defined regions of flexibility within the tail and an unusual symmetry mismatch with the pentameric viral capsid protein into which they are inserted. Moreover, the receptors for reoviruses and adenoviruses, junctional adhesion molecule 1 and coxsackievirus and adenovirus receptor, respectively, also share key structural and functional properties. Although reoviruses and adenoviruses belong to different virus families and have few properties in common, the observed similarities between σ1 and fibre point to a conserved mechanism of attachment and an ancient evolutionary relationship. Copyright © 2003 John Wiley & Sons, Ltd.
Cloning of herpesviral genomes as bacterial artificial chromosomes
Authors: Adler Heiko , Messerle Martin , Koszinowski Ulrich H. 
Published: March 2003

AbstractHerpesviruses, which are important pathogens for both animals and humans, have large and complex genomes with a coding capacity for up to 225 open reading frames (ORFs). Due to the large genome size and the slow replication kinetics in vitro of some herpesviruses, mutagenesis of viral genes in the context of the viral genome by conventional recombination methods in cell culture has been difficult. Given that mutagenesis of viral genes is the basic strategy to investigate function, many of the herpesvirus ORFs could not be defined functionally. Recently, a completely new approach for the construction of herpesvirus mutants has been developed, based on cloning of the virus genome as a bacterial artificial chromosome (BAC) in E. coli. This technique allows the maintenance of viral genomes as a plasmid in E. coli and the reconstitution of viral progeny by transfection of the BAC plasmid into eukaryotic cells. Any genetic modification of the viral genome in E. coli using prokaryotic recombination proteins is possible, thereby allowing the generation of mutant viruses and facilitating the analysis of herpesvirus genomes cloned as infectious BACs. In this review, we describe the principle of cloning a viral genome as a BAC using murine gammaherpesvirus 68 (MHV‐68), a mouse model for gammaherpesvirus infections, as an example. Copyright © 2003 John Wiley & Sons, Ltd.
Scientific myth‐conceptions
Authors: Allchin Douglas 
Published: March 2003

AbstractUsing several familiar examples—Gregor Mendel, H. B. D. Kettlewell, Alexander Fleming, Ignaz Semmelweis, and William Harvey—I analyze how educators currently frame historical stories to portray the process of science. They share a rhetorical architecture of myth, which misleads students about how science derives its authority. Narratives of error and recovery from error, alternatively, may importantly illustrate the nature of science, especially its limits. Contrary to recent claims for reform, we do not need more history in science education. Rather, we need different types of history that convey the nature of science more effectively. © 2003 Wiley Periodicals, Inc. Sci Ed 87:329–351, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.10055
One foot on the dock and one foot on the boat: Differences among preservice science teachers' interpretations of field‐based science methods in culturally diverse contexts
Authors: Yerrick Randy K. , Hoving Timothy J. 
Published: March 2003

AbstractTo support lasting change in science classrooms, efforts must be made to assist teachers in understanding the outcomes of their pedagogical choices. The process of reflection is not limited to experienced teachers' experiences, though we must recognize that preservice teachers do not draw upon the same vast repertoire and knowledge. The purpose of this study was to investigate preservice science teachers' beliefs about science teaching and learning through reflections on their own teaching with lower track science students. Using the major data sources of videotapes of teaching, stimulated recall interviews, and student journals we studied preservice teachers enrolled in a field based secondary science methods course working predominantly with rural Black children. Initially, preservice science teachers demonstrated similar practices, made similar inferences about teaching and learning, and relied upon similar domains of knowledge to gauge their teaching. By the end of the study, two discrete categories of preservice teachers emerged: (1) those who demonstrated an ability to reflect on and revise their practices and engage in the production of new teacher knowledge and (2) those who seemingly deflected efforts to shift their thinking and instead reproduced their own educational experience with a new student population. Implications for teacher education and research are discussed. © 2003 Wiley Periodicals, Inc. Sci Ed 87:390–418, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.10057