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Thermal conductivity of spin-12chains

Efrat Shimshoni、Natan Andrei、Achim Rosch2003-09-02Physical review. B, Condensed matter

We study the low-temperature transport properties of clean one-dimensional spin-$\frac{1}{2}$ chains coupled to phonons. Due to the presence of approximate conservation laws, the heat current decays very slowly giving rise to an exponentially large heat conductivity, $\ensuremath{\kappa}\ensuremath{\sim}{e}^{{T}^{*}/T…

Thermal properties of materialsQuantum and electron transport phenomenaPhysics of Superconductivity and Magnetism

Jahn-Teller distortions and excitation energies in C60(n+)

Martin Lueders、Nicola Manini2003-09-02arXiv

Based on previously computed parameters for the electron-phonon couplings and the Coulomb exchange, we compute and classify the static Jahn-Teller distortions, i.e. the minima of the lowest adiabatic potential energy surface, of C60(n+), for all values of charge 1 <= n <= 9 and spin. We compute the intra-band electron…

Materials ScienceStrongly Correlated Electrons

Low temperature irreversibility induced by thermal cycles on two prototypical phase separated manganites

J. Sacanell、M. Quintero、J. Curiale 等 11 位作者2003-09-02arXiv

We have studied the effect of irreversibility induced by repeated thermal cycles on the electric transport and magnetization of polycrystalline samples of La0.5Ca0.5MnO3 and La0.325Pr0.3Ca0.375MnO3. An increase of the resistivity and a decrease of the magnetization at different temperature ranges after cycling is obta…

Materials Science

The enhancement of phase separation aspect in electron doped manganite Ca0.8Sm0.16Nd0.04MnO3

D. A. Filippov、K. V. Klimov、R. Z. Levitin 等 6 位作者2003-09-02arXiv

The complex lanthanide doping of electron manganites results in enhancement of various phase separation effects in physical properties of these compounds. Selecting Ca0.8Sm0.16Nd0.04MnO3 as a model case we show that the first order structural phase transition from paramagnetic semi-metallic phase into anti-ferromagnet…

Strongly Correlated ElectronsMaterials Science

In-situ diagnostics of the crystalline nature of single organic nanocrystals by nonlinear microscopy

Sophie Brasselet、Veronique Le Floc'h、Francois Treussart 等 7 位作者2003-09-02arXiv

We elucidate the crystalline nature and the three-dimensional orientation of isolated organic nanocrystals embedded in a sol-gel matrix, using a polarized nonlinear microscopy technique that combines two-photon fluorescence and second harmonic generation. This technique allows the distinction between mono-crystalline…

Materials Science

Atomic scale lattice distortions and domain wall profiles

K. H. Ahn、Turab Lookman、Avadh Saxena 等 4 位作者2003-09-02Physical review. B, Condensed matter

We present an atomic scale theory of lattice distortions using strain-related variables and their constraint equations. Our approach connects constrained atomic length scale variations to continuum elasticity and describes elasticity at several length scales. We apply the approach to a two-dimensional square lattice w…

Force Microscopy Techniques and ApplicationsMechanical and Optical ResonatorsNonlocal and gradient elasticity in micro/nano structures

Evidence of decoupled lattice distortion and ferroelectric polarization in the relaxor system PMN-xPT

Guangyong Xu、D. Viehland、J. F. Li 等 5 位作者2003-09-02arXiv

We report high $q$-resolution neutron scattering data on PMN-$x$PT single crystals with $x=20%$ and 27%. No rhombohedral distortion occurs in the 20PT sample for temperatures as low as 50 K. On the other hand, the 27PT sample transforms into a rhombohedral phase below T$_C \sim 375$ K. Our data provide conclusive evid…

Materials Science

Nitrogen local electronic structure in Ga(In)AsN alloys by soft-X-ray absorption and emission: Implications for optical properties

V. N. Strocov、P. O. Nilsson、T. Schmitt 等 10 位作者2003-09-02arXiv

Soft-X-ray emission and absorption spectroscopies with their elemental specificity are used to determine the local electronic structure of N atoms in Ga(In)AsN diluted semiconductor alloys (N concentrations about 3%) in view of applications of such materials in optoelectronics. Deviations of the N local electronic str…

Materials Science

Structural and electronic properties ofh-BN

Lei Liu、Yuan Ping Feng、Zexiang Shen2003-09-02OpenAlex

Effects of stacking behavior of hexagonal basal layers to the structural stability and electronic properties of h-BN were investigated thoroughly using first-principles calculations based on the density-functional theory local-density approximation. Three of five possible h-BN structures with ``good'' stacking were fo…

Metal and Thin Film MechanicsBoron and Carbon Nanomaterials ResearchGraphene research and applications

The effect of Cu and Al on the mechanical properties of gravity-cast hyper-eutectic Zn–Al-based alloys

Ahmet Türk、M. Durman、S. Kayali2003-09-01International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde)

Abstract A series of Zn– Al-based alloys, one group with 1% Cu and the other without Cu, was produced by using gravity casting. The effect of Al content on hardness, ultimate tensile strength (UTS), impact strength, and tensile creep behaviour at 120 °C and an applied stress of 40 MPa has been investigated. It has bee…

Magnesium Alloys: Properties and ApplicationsCorrosion Behavior and InhibitionAluminum Alloys Composites Properties

Optimized Brazing Conditions of Regenerative Cooling Thrust Chambers

Dae-Geun Nam、Seok-Ho Hong、Gyu-Seok Han2003-09-01Journal of the Korean Society for Aeronautical & Space Sciences

본 연구에서는 재생 냉각용 연소기에 적용되고 있는 동합금과 2상 스테인리스강의 최적 브레이징 조건을 구하였다. 모재는 C18200 동합금과 S31803 2상 스테인레스강을, 삽입금속으로 두께가 각각 50<TEX>${\mu}m$</TEX>, 80<TEX>${\mu}m$</TEX>인 AMS4764를 사용하였다. 브레이징한 시제에 대하여 X선 검사, 강도/기밀 및 파괴시험, 파단면 관찰을 한 결과 두께 50<TEX>${\mu}m$</TEX>인 삽입금속을 사용한 경우 강도특성과 접합면이 양호함을 확인하였다. 반면 두께 80<TEX>${\mu}m$</TEX>인 삽입금속을 사…

Nuclear reactor physics and engineeringGraphite, nuclear technology, radiation studies

Surface Modification of Fibers via Graft-Site Amplifying Polymers

Stephen Michielsen2003-09-01International Nonwovens Journal

The surface properties of fibers play critical roles in many applications such as wicking, soil resistance, adhesion, and bio-compatibility. This paper will discuss a new approach to surface modification in which polymers are grafted to naturally occurring graft-sites on the substrate. The surface modifying polymers c…

Surface Modification and SuperhydrophobicityElectrospun Nanofibers in Biomedical Applications

Quantitative 3D-Analyses in SEM: A Review

Bernd Minnich、Wolf-Dietrich Krautgartner、Alois Lametschwandtner2003-09-01Microscopy and Microanalysis

Bernd Minnich, Wolf-Dietrich Krautgartner, Alois Lametschwandtner; Quantitative 3D-Analyses in SEM: A Review, Microscopy and Microanalysis, Volume 9, Issue S03,

Anodic Oxide Films and NanostructuresElectron and X-Ray Spectroscopy TechniquesCorrosion Behavior and Inhibition

Reactivity in the System Copper/Arsenic/Sulfur II. The Formation of CuAsS, (Lautite)

Achim Müller、R. Blachnik2003-09-01Zeitschrift für anorganische und allgemeine Chemie

Abstract The reaction pathways during the synthesis of CuAsS have been studied with the DTA in the range 25 — 810 °C with a heating rate of 10 K/min. Educts, intermediates, and products were characterized by X‐ray diffraction at room and elevated temperatures. Educts were the corresponding elements and the binary comp…

Arsenic contamination and mitigationCrystal Structures and PropertiesMetal Extraction and Bioleaching

Study of the viscoelastic properties of PET by thermally stimulated recovery

Natália M. Alves、José Luís Gómez Ribelles、João F. Mano2003-09-01Plastics Rubber and Composites Macromolecular Engineering

The conformational chain mobility of semi-crystalline poly(ethylene terephthalate), PET, is studied in the glass transition region by thermally stimulated recovery (TSR). The thermal sampling (TS) experiments are analysed according to a simple VoigtKelvin model. Both the activation energy (Ea ) and the pre-exponential…

Material Dynamics and PropertiesPolymer Nanocomposites and PropertiesPolymer crystallization and properties

Prevention of Rubber Degradation by Use of Microencapsulated Antioxidants

Takahiro Kataoka、Per B. Zetterlund、Bunichiro Yamada2003-09-01Rubber Chemistry and Technology

Abstract A new approach of preventing evaporation and migration of antioxidants in rubber is presented. The antioxidant N -1,3-dimethylbutyl- N '-phenyl- p -phenylenediamine (6PPD) was microencapsulated in silica (MC6PPD) prior to compounding with the rubber. The microencapsulated antioxidants were characterized by di…

Polymer crystallization and propertiesPolymer Nanocomposites and PropertiesThermal and Kinetic Analysis

COCRYSTALLIZATION OF LOW AMMOUNTS OF M2+ IONS DURING CoSO(4)7H2O CRYSTALLIZATION

Marek Smolik2003-09-01Journal of the Chilean Chemical Society

The equilibrium cocrystallization coefficients D M/CoSO4.7H2O of low amounts (10-3- 10-1%w/w) of M2+ ions (M2+ = {Ni2+, Mg2+, Cu2+, Zn2+, Fe2+, Mn2+, Cd2+, Ca2+}) with CoSO(4)7H2O have been determined with the method of long-time stirring of crushed CoSO(4)7H2O crystals in their saturated solution at 20ºC and compared…

Calcium Carbonate Crystallization and InhibitionChemical and Physical Properties in Aqueous SolutionsCrystallization and Solubility Studies

Studies of Poly(Styrene-co-Allyl Alcohol)/Polyester Blends Using Fourier Transform Infrared Spectroscopy and Imaging

Sung Joon Oh、Jong Soo、Jong Hoa Ok2003-09-01Applied Spectroscopy

The interaction of poly(styrene-co-allyl alcohol) and aliphatic polyester was studied using FT-IR spectroscopy. The hydrogen bonding between two polymers was investigated by monitoring C=O and OH stretching modes with the variation of concentration and temperature. The phase-separated morphology was also observed usin…

Spectroscopy and Chemometric AnalysesNonlinear Optical Materials ResearchLiquid Crystal Research Advancements

Shock properties of diamond and kimberlite

Geoff R. Willmott、William G. Proud、J. E. Field2003-09-01Journal de Physique IV (Proceedings)

Plate impact experiments have been performed on diamond and the igneous diamond-bearing matrix kimberlite. Longitudinal and lateral stresses within kimberlite have been measured in the uniaxial strain regime using embedded manganin stress gauges. The shock Hugoniot of the kimberlite has been characterised, and the ela…

Diamond and Carbon-based Materials ResearchHigh-pressure geophysics and materialsGeological and Geochemical Analysis

Chemical Behaviors of Energetic Deuterium Implanted into Boron Coatings

Hiroshi Kodama、Y. Morimoto、M. Sasaki 等 8 位作者2003-09-01Fusion Science & Technology

To study chemical behaviors of energetic deuterium implanted into boron coating deposited by boronization in fusion devices, two types of boron coating film deposited on silicon and IG-430U were prepared by Plasma Chemical Vapor Deposition (PCVD) technique. Boron polycrystal was used as the reference sample. The chemi…

Metal and Thin Film MechanicsDiamond and Carbon-based Materials ResearchBoron and Carbon Nanomaterials Research