Ivo B. Rietveld、Jan A. M. Smit1999-06-11Macromolecules
The colligative properties of poly(propylene imine) dendrimers in methanol have been investigated with low-angle laser light scattering and vapor pressure osmometry. The molecular weights and second virial coefficients of the first five generations have been determined. The molecular weights have been found to agree w…
Advanced Polymer Synthesis and CharacterizationSynthesis and properties of polymersDendrimers and Hyperbranched Polymers
D. M. Gruen、Paul C. Redfern、David A. Horner 等 5 位作者1999-06-11The Journal of Physical Chemistry B
Density functional theory and ab initio molecular orbital theory have been used to calculate the energetics of C 2 insertion into C 9 H 12 and C 9 H 14 clusters that model unhydrided and monohydrided (100) diamond surfaces, respectively. The reaction of C 2 with either the C 9 H 12 or C 9 H 14 cluster is exothermic by…
Fullerene Chemistry and ApplicationsDiamond and Carbon-based Materials ResearchHigh-pressure geophysics and materials
Alexandra Navrotsky1999-06-11Science
Understanding the processes in Earth9s lower mantle requires detailed knowledge of the composition, phase, and physical properties of the mantle minerals, chiefly magnesium silicates with a perovskite structure. Navrotsky (page 1788) argues that lessons can be learned from ceramic perovskites that have been studied in…
Fuel Cells and Related MaterialsHigh-pressure geophysics and materialsAdvancements in Solid Oxide Fuel Cells
Vladimir Privman1999-06-11arXiv
In this work we survey selected theoretical developments for models of deposition of extended particles, with and without surface diffusion, on linear and planar substrates, of interest in colloid, polymer, and certain biological systems.
cond-mat.stat-mechSoft Condensed MatterMaterials Science
S. Curtarolo、G. Stan、M. J. Bojan 等 5 位作者1999-06-11arXiv
Grand canonical simulations are used to calculate adsorption isotherms of various classical gases on alkali metal and Mg surfaces. Ab initio adsorption potentials and Lennard-Jones gas-gas interactions are used. Depending on the system, the resulting behavior can be nonwetting for all temperatures studied, complete we…
cond-mat.stat-mechMaterials Science
Yi Liao、Chunping Xie、Paul M. Lahti 等 6 位作者1999-06-10The Journal of Organic Chemistry
The title diradical was synthesized and investigated by ESR and UV−vis spectroscopy. It was found to have a lifetime of weeks even in the presence of oxygen, and even survives brief heating in toluene up to about 60 °C. In the UV−vis spectrum, the diradical showed reversible thermochromic behavior in the −10 to 50 °C…
Magnetism in coordination complexesElectron Spin Resonance StudiesLanthanide and Transition Metal Complexes
Leonardo E. Silbert、J. R. Melrose、R. C. Ball1999-06-10Molecular Physics
Using both instantaneous snapshots and simulation generated scattering data, the steady-state flow behaviour of a concentrated aggregated colloidal suspension is analysed in terms of its structure factor S(k). We find that in the shear thinning regime, unlike model hard sphere results, S(k) exhibits pre-peaks at small…
Material Dynamics and PropertiesPickering emulsions and particle stabilizationRheology and Fluid Dynamics Studies
David Wick、Ty Martínez、Michael V. Wood 等 9 位作者1999-06-10Applied Optics
New liquid-crystal media and photoconductor materials are being utilized in spatial light modulators to increase their resolution, diffraction efficiency, speed, and sensitivity. A prototypical device developed for real-time holography applications has shown an 8% diffraction efficiency from a holographic grating with…
Advanced Optical Imaging TechnologiesPhotorefractive and Nonlinear OpticsLiquid Crystal Research Advancements
Wei Wang、Xiao Chen、Shlomo Efrima1999-06-10Chemistry of Materials
We study the in situ fabrication of copper sulfide nanoparticles within a three-dimensional (3D) organic-layered solid crystal of alkylammonium−metal complexes by their reaction with H 2 S gas. UV−vis spectroscopy and high-resolution electron microscopy are used to monitor the formation of the nanoparticles and to cha…
Chalcogenide Semiconductor Thin FilmsQuantum Dots Synthesis And PropertiesPerovskite Materials and Applications
Raymond J. Stockermans、P. Rochon1999-06-10Applied Optics
Resonant grating waveguide structures were used to fabricate narrow-bandwidth optical filters. Azopolymer films were deposited on top of slab waveguides, and surface relief gratings were optically inscribed on them to be used as couplers. This technique is a simple one-step process and produces efficient gratings with…
Photonic Crystals and ApplicationsPhotonic and Optical DevicesOptical Coatings and Gratings
Sean Langridge、Joerg Schmalian、C. H. Marrows 等 5 位作者1999-06-10arXiv
The in-plane correlation lengths and magnetic disorder of magnetic domains in a transition metal multilayer have been studied using neutron scattering techniques. A new theoretical framework is presented connecting the observed scattering to the in-plane correlation length and the dispersion of the local magnetization…
Materials Sciencecond-mat.dis-nn
H. Ness、A. J. Fisher1999-06-10arXiv
We calculate non-perturbatively the inelastic effects on the conductance through a conjugated molecular wire-metal heterojunction, including realistic electron-phonon coupling. We show that at sub-band-gap energies the current is dominated by quantum coherent transport of virtual polarons through the molecule. In this…
Materials Science
I. I. Mazin1999-06-10arXiv
Different ways to define and to calculate the degree of spin polarization in a ferromagnet are discussed, particularly with respect to spin-polarized tunneling and Andreev reflection at the boundary between a superconductor and ferromagnet. As an example, the degrees of spin polarization for different experiments in F…
Materials Science
Jian-Xin Zhu、C. S. Ting1999-06-10arXiv
The induction of an s-wave component in a d-wave superconductor is considered. Near the {110}-oriented edges of such a sample, the induced s-wave order parameter together with d-wave component forms a complex combination d+e^{iϕ} s, which breaks the time reversal symmetry (BTRS) of the pairing state. As a result, the…
Materials ScienceSuperconductivity
J. F. de Lima、M. E. G. Valerio、E. Okuno1999-06-10arXiv
In this work we investigate the effect of gamma and ultraviolet radiations on the thermoluminescence of Brazilian calcite. The irradiated samples presented three TL peaks at 150, 245 and 320^oC (at a linear heating rate of 1.8^oC/s), with a main emission band centered at 615nm due to the ^4G \to ^6S transition of the…
Materials Science
Marcelo J. Dapino、Ralph C. Smith、Alison B. Flatau1999-06-09Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
The growing interest in giant magnetostrictive materials for generation of strains in smart structure systems motivates the development of increasingly accurate performance prediction and optimization tools. We propose a model for the strains generated by magnetostrictive materials in response to applied magnetic fiel…
Piezoelectric Actuators and ControlShape Memory Alloy TransformationsMagnetic Properties and Applications
Valentin Alexiev、Holger Meyer zu Altenschildesche、R. Prins 等 4 位作者1999-06-09Chemistry of Materials
Solid-state NMR has been used to study the local coordination environments of the protons and alkali metal cations in hydrated alkali metal intercalation compounds of MoS 2, A x (H 2 O) y MoS 2 (A = Li, Na, K, Cs). The dynamic behavior of the water molecules, which are coordinated to the intercalated A + cations, is c…
Chemical Synthesis and CharacterizationAdvanced NMR Techniques and ApplicationsSolid-state spectroscopy and crystallography
Rick A. Kellogg、Alison B. Flatau1999-06-09Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
The output force-strain relationship typical of the performance of Terfenol-D transducers under varied operating conditions is examined to study transducer blocked force characteristics. The design and construction of a transducer for testing under controlled thermal, magnetic and mechanical load conditions are descri…
Non-Destructive Testing TechniquesElectromagnetic Effects on MaterialsMagnetic Properties and Applications
Christophe Paget、Klas Levin1999-06-09Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
The objective of this paper is to determine the strength reduction due to the embedment of a piezoelectric ceramic transducer in a composite. The composite was made from carbon/epoxy prepreg with a cross-ply lay-up. The transducer was embedded in the mid-plane of the composite material. The specimens were tested in te…
Material Properties and ApplicationsMechanical and Thermal Properties AnalysisEngineering Applied Research
Kevin W. McCreight、Jason J. Ge、Mingming Guo 等 9 位作者1999-06-09Journal of Polymer Science Part B Polymer Physics
A series of organo-soluble hairy-rod polyimides was recently synthesized from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and di[n-alkyl]-4,4′-diamino-6,6′-dibromo-2,2′-biphenyldicarboxylate with side chains of varying lengths (the numbers of methylene units), BACBP(n). Dynamic mechanical (DM) results reveal…
Synthesis and properties of polymersEpoxy Resin Curing ProcessesLiquid Crystal Research Advancements