Xin Weng、Christopher Y. Li、Shi Jin 等 9 位作者2002-11-21Macromolecules
A nonracemic chiral main-chain liquid crystalline (LC) polyester was synthesized from ( R )-(−)-4‘-{ω-[2-( p -hydroxy- o -nitrophenyloxy)-1-propyloxy]-1-undecyloxy}-4-biphenylcarboxylic acid via an A−B type condensation polymerization. The polymer was abbreviated as PET(R*-11), where 11 is the number of methylene unit…
Liquid Crystal Research AdvancementsSynthesis and Properties of Aromatic CompoundsMolecular spectroscopy and chirality
Daniel Duque、K. B. Katsov、M. Schick2002-11-21The Journal of Chemical Physics
We apply self-consistent-field theory to T junctions and symmetric tilt grain boundaries in block copolymer systems with and without the addition of homopolymer. We find that, in the absence of homopolymer, T junctions have a larger free energy per unit area than that of the symmetric tilt junctions with which they co…
Theoretical and Computational PhysicsRheology and Fluid Dynamics StudiesBlock Copolymer Self-Assembly
Zeger Hens、D. V. Tallapin、Horst Weller 等 4 位作者2002-11-21Applied Physics Letters
Nanometer-sized insulating quantum dots (CdSe and ZnO) have been attached to a Au(111) substrate, using molecular bridges with thiol and carboxylate end functions. We demonstrate that the quantum dots can be probed by a scanning tunneling microscope at negative substrate bias. At positive bias, however, the gold–sulfu…
Quantum Dots Synthesis And PropertiesMolecular Junctions and NanostructuresSurface and Thin Film Phenomena
Andrea Alù、Nader Engheta2002-11-21Microwave and Optical Technology Letters
Abstract In this paper, we present an analysis for the radiation from a traveling‐wave infinitely‐extent sheet of monochromatic electric current that is placed at the interface between a conventional lossless dielectric and a lossless material possessing negative real permittivity and permeability. The field distribut…
Antenna Design and AnalysisMetamaterials and Metasurfaces ApplicationsAdvanced Antenna and Metasurface Technologies
I. Rychetský、J. Petzelt、T. Ostapchuk2002-11-21Applied Physics Letters
Grain-boundary and crack effects on the dielectric response of high-permittivity films and ceramics were analyzed using the generalized effective-medium approximation. It was demonstrated that the brick-wall and coated spheres models, which become equivalent for a small porosity, best describe the strong reduction of…
Ferroelectric and Piezoelectric MaterialsAcoustic Wave Resonator TechnologiesMicrowave Dielectric Ceramics Synthesis
Qing-An Zhang、Yumiko Nakamura、Ken‐ich Oikawa 等 5 位作者2002-11-21Inorganic Chemistry
The title hydride and its deuteride were successfully synthesized. The crystal structure of the deuteride was determined by time-of-flight neutron powder diffraction. BaAlD(5) crystallizes with a new orthorhombic structure in space group Pna2(1) (No. 33), cell parameters a = 9.194(1) A, b = 7.0403(9) A, and c = 5.1061…
Hydrogen Storage and MaterialsAmmonia Synthesis and Nitrogen ReductionMuon and positron interactions and applications
Xuhui Sun、Chi-Pui Li、Ning‐Bew Wong 等 6 位作者2002-11-21Journal of the American Chemical Society
A new type of well-structured, hydrocarbon nanomaterial including nanotubes and onions, with interlayer spacing ranging from 3.4 to 5.8 A, was discovered by reacting SiNWs with common organic solvents in a laboratory sonicator under ambient conditions (room temperature and atmospheric pressure).
Carbon Nanotubes in CompositesNanowire Synthesis and ApplicationsNanotechnology research and applications
Takashi Taniguchi、Kenji Watanabe、Satoshi Koizumi 等 6 位作者2002-11-21Applied Physics Letters
Ultraviolet light emission at a wavelength of 250 nm was observed from Be-doped single crystals of cubic boron nitride (cBN) grown at high pressure and high temperatures. We found that dopants of Be were localized in the grown crystals when a small amount of Be was added to the crystals. The crystals had boundaries of…
GaN-based semiconductor devices and materialsLuminescence and Fluorescent MaterialsBoron and Carbon Nanomaterials Research
M. Elisa Milanesio、Miguel Gervaldo、Luís Otero 等 6 位作者2002-11-21Journal of Physical Organic Chemistry
Abstract Zn(II) porphyrin–C 60 dyad ( 7 ) was synthesized by the coupling reaction between Zn(II) 5‐(4‐aminophenyl)‐10,15,20‐tris(4‐methoxylphenyl)porphyrin ( 4 ) and 1,2‐dihydro‐1,2‐methanofullerene[60]‐61‐carboxylic acid ( 6 ). The electron‐donor capacity of the porphyrin moiety in dyad 7 is enhanced by methoxy grou…
Graphene research and applicationsPorphyrin and Phthalocyanine ChemistryFullerene Chemistry and Applications
J. W. Chiou、C. L. Yueh、J. C. Jan 等 16 位作者2002-11-21Applied Physics Letters
Angle-dependent x-ray absorption near edge structure (XANES) and scanning photoelectron microscopy (SPEM) measurements have been performed to differentiate local electronic structures of the tips and sidewalls of highly aligned carbon nanotubes. The intensities of both π*- and σ*-band C K-edge XANES features are found…
Carbon Nanotubes in CompositesGraphene research and applicationsBoron and Carbon Nanomaterials Research
Qin Zhang、Yong Wang、Qiang Fu2002-11-21Journal of Polymer Science Part B Polymer Physics
Abstract For the improved dispersion of montmorillonite (MMT) in a polypropylene (PP) matrix, PP/MMT nanocomposites prepared via direct melt intercalation were further subjected to oscillating stress achieved by dynamic packing injection molding. The shear‐induced morphological changes were investigated with an Instro…
Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties
Pi‐Ling Wu、Eamor M. Woo2002-11-21Journal of Polymer Science Part B Polymer Physics
Abstract The lamellar types as revealed by the multiple melting peaks and possible mechanisms of ringed spherulites in poly(trimethylene terephthalate) (PTT) were analyzed with differential scanning calorimetry (DSC), optical microscopy, and scanning electron microscopy. Several interesting correlations were found. If…
Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties
Andrew J. Schultz、Carol K. Hall、Jan Genzer2002-11-21The Journal of Chemical Physics
Discontinuous molecular dynamics simulation is used to study the phase behavior of diblock copolymers modeled as chains of tangent hard spheres with square shoulder repulsions between unlike species as a function of chain length, volume fraction and interaction strength (χ). The location of the order–disorder transiti…
Material Dynamics and PropertiesRheology and Fluid Dynamics StudiesBlock Copolymer Self-Assembly
Grant D. Smith、Oleg Borodin、Wolfgang Paul2002-11-21The Journal of Chemical Physics
We have carried out atomistic molecular dynamics simulations of a melt of 1,4-poly(butadiene) from temperatures well above the experimentally observed merging of the primary α process and secondary β process down to temperatures approaching the experimentally observed bifurcation temperature. The relaxation strength a…
Polymer crystallization and propertiesMaterial Dynamics and PropertiesAcoustic Wave Phenomena Research
Habib Skaff、Todd Emrick2002-11-21Chemical Communications
Amphiphilic cadmium selenide (CdSe) nanoparticles were prepared by surface functionalization with novel ligands 1 and 2, composed of pyridine moieties substituted in the 4-position with polyethylene glycol (PEG) chains.
Quantum Dots Synthesis And PropertiesChalcogenide Semiconductor Thin FilmsNanocluster Synthesis and Applications
Carl McBride、Carlos Vega2002-11-21The Journal of Chemical Physics
A study of a rigid fully flexible fused hard sphere model [C. McBride, C. Vega, and L. G. MacDowell, Phys. Rev. E 64, 011703 (2001)] is extended to the smectic and solid branches of the phase diagram. Computer simulations have been performed for a completely rigid model composed of 15 fused hard spheres (15+0), a mode…
Liquid Crystal Research AdvancementsPhase Equilibria and ThermodynamicsMaterial Dynamics and Properties
Rubén Nares、Jorge Ramı́rez、Aída Gutiérrez‐Alejandre 等 5 位作者2002-11-21The Journal of Physical Chemistry B
The deposition−precipitation (DP) method, which was extensively developed for the preparation of Ni/SiO 2, is applied here to the preparation of Ni/Hβ zeolite catalysts. The Ni/Hβ samples prepared at different deposition−precipitation times (1−4 h) were characterized by BET, XRD, TPR, FTIR, SEM, and TEM. The results i…
Catalytic Processes in Materials ScienceZeolite Catalysis and SynthesisMesoporous Materials and Catalysis
Jianhua Hao、Michael Cocivera2002-11-21Applied Physics Letters
Spray pyrolysis was used to deposit thin films of Ba2B5O9Cl:Eu from aqueous solutions containing Eu3+. Blue cathodoluminescence due to the abnormal reduction of Eu3+→Eu2+ in as-grown thin films was observed at the growth temperatures from 140 °C to 500 °C. Significant line narrowing was found as the growth temperature…
Luminescence Properties of Advanced MaterialsPerovskite Materials and ApplicationsLuminescence and Fluorescent Materials
Junjun Liu、Dongwen Gan、Chuan Hu 等 7 位作者2002-11-21Applied Physics Letters
This letter reports a study of the porosity effect on material properties of methylsilsesquioxane films, including the dielectric constant, thermal conductivity, and thermal stress behavior. In a porosity range from 0% to 50%, both the dielectric constant and thermal conductivity decreased with increasing porosity and…
Advanced ceramic materials synthesisAerogels and thermal insulationSilicone and Siloxane Chemistry
Dimitri A. Ivanov、Tatiana Pop、Do Y. Yoon 等 4 位作者2002-11-21Macromolecules
We report on the direct evidence in real space of the crystal−amorphous interphase in a lamellar semicrystalline polymer, poly(ethylene terephthalate) (PET). This evidence was obtained by the TEM observation of the compositional variation of (stained) PET segments in the boundary of an isolated lamellar stack in a bin…
Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties