Jianhua Hao、Weidong Si、X. X. Xi 等 6 位作者2000-05-22Applied Physics Letters
We have deposited CaTiO3 thin films on SrRuO3 electrode layers on SrTiO3 and LaAlO3 substrates by pulsed laser deposition. The low-frequency dielectric properties were measured from 4 to 300 K. We found that the dielectric constants of 1-μm-thick CaTiO3 films are very close to that observed in the bulk materials. The…
Ferroelectric and Piezoelectric MaterialsMagnetic and transport properties of perovskites and related materialsElectronic and Structural Properties of Oxides
P. M. Johnson、D. A. Olson、S. Pankratz 等 7 位作者2000-05-22Physical Review Letters
The unit cell structures of two ferrielectric liquid-crystal phases are determined from ellipsometric studies of freestanding films in a nondistorting rotatable electric field. A highly biaxial mode with out-of-plane distortions describes all of the data from two different compounds. Qualitative and quantitative featu…
Liquid Crystal Research AdvancementsSurfactants and Colloidal SystemsPlant Reproductive Biology
Chin Li Cheung、Jason H. Hafner、Teri W. Odom 等 5 位作者2000-05-22Applied Physics Letters
Single-walled carbon nanotube (SWNT) probe microscopy tips were grown by a surface growth chemical vapor deposition method. Tips consisting of individual SWNTs (1.5–4 nm in diameter) and SWNT bundles (4–12 nm in diameter) have been prepared by design through variations in the catalyst and growth conditions. In additio…
Carbon Nanotubes in CompositesForce Microscopy Techniques and ApplicationsMechanical and Optical Resonators
Jörg P. Kottmann、Olivier J. F. Martin、David R. Smith 等 4 位作者2000-05-22Optics Express
We study the plasmon resonances of 10 (nm)--100 (nm) two-dimensional metal particles with a non-regular shape. Movies illustrate the spectral response of such particles in the optical range. Contrary to particles with a simple shape (cylinder, ellipse) non-regular particles exhibit many distinct resonances over a larg…
Gold and Silver Nanoparticles Synthesis and ApplicationsPlasmonic and Surface Plasmon ResearchNonlinear Optical Materials Studies
G. P. Johari2000-05-22The Journal of Chemical Physics
The literature data on the entropy and heat capacity of 33 glass-forming liquids have been used to examine the validity of the Adam–Gibbs relation between a liquid’s configurational entropy, Sconf, and its molecular kinetics. The critical entropy, sc*, of kB ln 2 (=0.956×10−23 J molecule−1 K−1) in the equation is less…
Phase Equilibria and ThermodynamicsMaterial Dynamics and PropertiesThermodynamic properties of mixtures
Pascal Ruffieux、Oliver Gröning、P. Schwaller 等 5 位作者2000-05-22Physical Review Letters
We report on long-range electronic effects caused by hydrogen-carbon interaction at the graphite surface. Two types of defects could be distinguished with a combined mode of scanning tunneling microscopy and atomic force microscopy: chemisorption of hydrogen on the basal plane of graphite and atomic vacancy formation.…
Carbon Nanotubes in CompositesGraphene research and applicationsChemical and Physical Properties of Materials
H. Kageyama、M. Nishi、N. Aso 等 9 位作者2000-05-22arXiv
We performed inelastic neutron scattering on the 2D Shastry-Sutherland system SrCu2(11BO3)2 with an exact dimer ground state. Three energy levels at around 3, 5 and 9 meV were observed at 1.7 K. The lowest excitation at 3.0 meV is almost dispersionless with a bandwidth of 0.2 meV at most, showing a significant constra…
Materials ScienceStrongly Correlated Electrons
E. M. Chudnovsky、D. A. Garanin2000-05-22arXiv
Recently Leuenbeger and Loss suggested a theory of phonon-assisted relaxation in a molecular nanomagnet Mn-12 that "contrary to previous results is in reasonably good agreement ... with all experimental parameter values known so far". The purpose of this Comment is to show that the model of Leuenberger and Loss and it…
Materials Sciencecond-mat.stat-mech
Zhi-Rong Liu、Jian-She Liu、Bing-Lin Gu 等 4 位作者2000-05-22arXiv
The atomic ordering in complex perovskite alloys is investigated by the cluster variation method (CVM). For the 1/3\{111\}-type ordered structure, the order-disorder phase transition is the first order, and the order parameter of the 1:2 complex perovskite reaches its maximum near x=0.25. For the 1/2\{111\}-type order…
Materials Sciencecond-mat.stat-mech
E. M. Chudnovsky、D. A. Garanin2000-05-22arXiv
Recently, Bellessa et al in a Physical Review Letter entitled "Phonon-Assisted Tunneling in High-Spin Molecules: Experimental Evidence", reported observation of a peak in the imaginary part of the ac-susceptibility of Mn-12 molecular nanomagnet, that decreases strongly below 0.1 K down to 0.02 K. They explained this e…
Materials Sciencecond-mat.stat-mech
Tobias Hertel、Gunnar Moos2000-05-22Physical Review Letters
We investigate the electron-phonon (e-ph) interaction in single-wall carbon nanotube samples at room temperature using femtosecond time-resolved photoemission. By probing electrons from the vicinity of the Fermi level we are able to study the e-ph interaction in the metallic nanotube species only. The observed electro…
Carbon Nanotubes in CompositesGraphene research and applicationsFullerene Chemistry and Applications
Jean-Luc Béchade、R. Dralet、P. Goudeau 等 4 位作者2000-05-21Materials science forum
The aim of this study is the determination of the residual stress state and the analysis of the microstructure of ZrO 2 oxide layers (mainly the tetragonal to monoclinic phase ratio) formed on different zirconium alloy plates oxidized in steam at 400°C for several lengths of time, using x-ray diffraction techniques. T…
Fusion materials and technologiesHigh-Temperature Coating BehaviorsNuclear Materials and Properties
Alexander M. Korsunsky、Mark R. Daymond、Karen E. Wells2000-05-21Materials science forum
To measure internal strains in an Al MMC, time-of-flight (TOF) ncutron diffraction was used on the ENGIN instrument at ISIS, RAL, in Oxfordshire, and a monochromated X-ray beam was employed on the BM16 beamline at the ESRF in Grenoble. The development of intergranular stresses between groups of grains possessing certa…
Microstructure and mechanical propertiesMicrostructure and Mechanical Properties of SteelsAluminum Alloy Microstructure Properties
Sang Yup Lee、Sang Yup Lee、Heng Ho Wong 等 9 位作者2000-05-20Biotechnology and Bioengineering
High-cell-density fed-batch cultures of Pseudomonas putida were carried out for the production of medium-chain-length polyhydroxyalkanoates (PHAs) using oleic acid as a carbon source. By employing an optimal feeding strategy without the limitation of any nutrient, a high cell concentration of 173 g/L was achieved, but…
Enzyme Catalysis and Immobilizationbiodegradable polymer synthesis and propertiesElectrospun Nanofibers in Biomedical Applications
H. S. Kim、Willie Lau、Eugenia Kumacheva2000-05-20Macromolecules
We have measured normal quasi-equilibrium forces between adsorbed layers formed on hydrophilic surfaces in aqueous solutions of telechelic poly(ethylene oxide) end-terminated with octadecyl groups. At low polymer concentrations, c pol, a monolayer adsorbs, which has properties similar to the monolayer of adsorbed nonh…
Surfactants and Colloidal SystemsPolymer Surface Interaction StudiesForce Microscopy Techniques and Applications
Zengmin Li、Chet Jablonski2000-05-20Inorganic Chemistry
Mono- (3a,b) and binuclear (4a,b) tetradentate NiII complexes of a series of 26-membered macrocyclic salen dimers, [salen(CH2)]2, are prepared in good yield by solvent-controlled reaction with Ni(OAc)2. The mononuclear complex 3b crystallizes in the trigonal space group 3P1(#144), a = 18.2566(2) A, c = 15.9244(2) A, V…
Metal complexes synthesis and propertiesPorphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation Mechanisms
Moshe Nakash、Zöe Clyde-Watson、N. Feeder 等 6 位作者2000-05-20Journal of the American Chemical Society
New cyclic metalloporphyrin hosts, 6 and 7, have been prepared. At 0.33 mM in dichloromethane at 25 °C, they accelerate 65-fold and 840-fold respectively the reaction of diene 1 and dienophile 2 and also bind the hetero Diels−Alder product 3 very strongly. More importantly, small single crystals of solvated 6, 7, and…
Porphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation MechanismsSurface Chemistry and Catalysis
Qin‐De Liu、Song Gao、Junran Li 等 9 位作者2000-05-20Inorganic Chemistry
The new heteronuclear iminodiacetic acid (H2L) complexes [LnCu6(mu 3-OH)3(HL)2(L)4](ClO4)(2).25H2O with Ln = La (1) and Tb (2) have been prepared in aqueous solution and characterized by single-crystal X-ray diffraction to be isomorphous (crystallographic data for 1 and 2: hexagonal, P63/m; a = b = 12.6425(14) A, c =…
Magnetism in coordination complexesLanthanide and Transition Metal ComplexesInorganic Fluorides and Related Compounds
Ippei Noda、Takeshi Kamoto、Masahiko Yamada2000-05-20Chemistry of Materials
Emulsion polymerization was used to prepare methylsilsesquioxane derivatives with an average particle size of 0.2−5.0 μm and various topological morphologies. Particles with an average particle size of 0.2−2.0 μm were prepared by emulsion polymerization using close to the critical micelle concentration of a nonionic e…
Surface Modification and SuperhydrophobicityPolymer Surface Interaction StudiesSilicone and Siloxane Chemistry
P. V. Vanitha、A. Arulraj、P. N. Santhosh 等 4 位作者2000-05-20Chemistry of Materials
The structure of Ln 0.5 Sr 0.5 CoO 3 is rhombohedral ( R 3̄ c ) when Ln = La, Pr, or Nd, but orthorhombic ( Pnma ) when Ln = Gd. The Ln 0.5 Ba 0.5 CoO 3 compounds, except for Ln = La, are orthorhombic ( Pmmm ). The ferromagnetic Curie temperature, T C, of Ln 0.5 A 0.5 CoO 3 increases with the average size of the A-sit…
Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsThermal Expansion and Ionic Conductivity