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Transport properties of cholesteric liquid crystals studied by molecular dynamics simulation

Sten Sarman2001-08-10Molecular Physics

We have studied the transport properties of a cholesteric liquid crystal by molecular dynamics simulation. The molecules consist of six soft ellipsoids of revolution, the axes of which are perpendicular to the line connecting their centres of symmetry. The angle between the symmetry axes of two adjacent ellipsoids is…

Liquid Crystal Research AdvancementsLipid Membrane Structure and BehaviorSurfactants and Colloidal Systems

<title>Radio- and VUV-excited luminescence of YAP:Ce, YAP:Pr and YAG:Pr</title>

M. Wiśniewska、A.J. Wojtowicz、Tadeusz Łukasiewicz 等 6 位作者2001-08-10Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

In this communication we report initial results of studies on x-ray and VUV excited luminescence of YAP and YAG crystals activated with Pr<SUP>3+</SUP> and YAP activated with Ce<SUP>3+</SUP>. Excitation and luminescence spectra of Pr<SUP>3+</SUP> and Ce<SUP>3+</SUP> d-f and Pr<SUP>3+</SUP> f-f emissions and luminescen…

Luminescence Properties of Advanced MaterialsSolid State Laser TechnologiesRadiation Detection and Scintillator Technologies

Synthesis and characterization of fully aromatic thermotropic liquid‐crystalline copolyesters containing m‐hydroxybenzoic acid units

Zekeri̇ya Yerli̇kaya、Serpi̇l Aksoy、Erdal Bayramlı2001-08-10Journal of Polymer Science Part A Polymer Chemistry

Abstract A series of fully aromatic copolyesters based on p ‐acetoxybenzoic acid ( p ‐ABA), hydroquinone diacetate (HQDA), terephthalic acid (TPA), and m ‐acetoxybenzoic acid ( m ‐ABA) were prepared by a modified melt‐polycondensation reaction. The copolyesters were characterized by DSC, thermogravimetric analysis, 1…

Liquid Crystal Research Advancementsbiodegradable polymer synthesis and propertiesSynthesis and properties of polymers

Antimicrobial Polymers and Fibers: Retrospective and Prospective

Tyrone L. Vigo2001-08-10ACS symposium series

Aproaches for imparting antimicrobial activity to polymeric materials have evolved from ancient practices to eclectic, modern strategies. The mechanisms by which microbes attach to polymeric surfaces and acquire resistance to antimicrobial agents are critically reviewed. Representative microorganisms (primarily bacter…

Silk-based biomaterials and applicationsMedical and Biological Ozone Research

Charge distribution and crystalline structure in polyethylene nucleated with sorbitol

Xiang Li、Yi Cao、Qiangguo Du 等 5 位作者2001-08-10Journal of Applied Polymer Science

Abstract The charge distribution in samples under direct current electrical field was measured by the pulsed electro‐acoustic method, which showed that the space charges were greatly decreased and field distribution tended to be uniform in low‐density polyethylene (LDPE) by adding 0.3 wt % bis‐( p ‐ethylbenzylidene)so…

Polymer crystallization and propertiesPolymer Nanocomposites and PropertiesNatural Fiber Reinforced Composites

<title>Nonlinear optical properties in ZnSe crystals</title>

Beata Derkowska‐Zielinska、B. Sahraoui、X. Nguyen Phu 等 4 位作者2001-08-10Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

The two photon absorption coefficient and third order nonlinear optical susceptibility of ZnSe crystals were investigated using the transmission and degenerate four wave mixing methods. The experimental results show that imaginary part of third order nonlinear optical susceptibility decrease with increase of free carr…

Nonlinear Optical Materials ResearchSpectroscopy Techniques in Biomedical and Chemical ResearchNonlinear Optical Materials Studies

Synthesis and ionic conductivity of hyperbranched poly(glycidol)

Wang Xinling、Chen Jianjun、Hong Ling 等 4 位作者2001-08-10Journal of Polymer Science Part B Polymer Physics

Abstract A novel hyperbranched poly(glycidol) (HPG) was prepared and characterized. The synthesized HPG was used as a substrate of a polymer electrolyte. The ionic conductivity of a blend of HPG, polyurethane (PU), and salt was studied. The ionic conductivity of HPG/PU/LiClO 4 was about 6.6 × 10 −6 S · cm −1 at 20 °C…

Fuel Cells and Related MaterialsConducting polymers and applicationsDendrimers and Hyperbranched Polymers

Polymer Films on Electrodes. 30. Electrochemistry and Scanning Electrochemical Microscopy Characterization of Benzimidazolebenzophenanthroline-Type Ladder (BBL) and Semiladder (BBB) Polymer Films

Maurizio Quinto、Samson A. Jenekhe、Allen J. Bard2001-08-10Chemistry of Materials

Polymer-modified electrodes were obtained by spin-coating solutions of poly(benzobisimidazobenzophenanthroline) ladder (BBL) and semiladder (BBB) polymers on indium−tin oxide electrodes. An electrochemical study of these films showed reproducible and stable cyclic voltammograms for reduction of the polymer (in the abs…

Conducting polymers and applicationsElectrochemical Analysis and ApplicationsAnalytical Chemistry and Sensors

Microsprings and microcantilevers: studies of mechanical response

M. Seto、Brian Dick、Michael J. Brett2001-08-10Journal of Micromechanics and Microengineering

Porous thin films with unique microstructures have been fabricated with the glancing angle deposition technique. This technique utilizes highly oblique deposition angles to make use of initial growth and shadowing conditions, which allow thin films consisting of microsprings and arrays of microcantilevers to be engine…

Metal and Thin Film MechanicsAdvanced Surface Polishing TechniquesOptical Coatings and Gratings

Paramagnetic Cobalt(II) as an NMR Probe of Dendrimer Structure: Mobility and Cooperativity of Dendritic Arms

Jon D. Epperson、Li‐June Ming、Gregory R. Baker 等 4 位作者2001-08-10Journal of the American Chemical Society

Cobalt(II) has been utilized as an external paramagnetic (1)H NMR probe for the study of the structure of dendrimers that possess specifically located metal recognition sites. The hyperfine-shifted (1)H NMR signals of the Co(II) complexes of several 2,6-diamidopyridine-containing dendrimers have been fully assigned by…

Metal complexes synthesis and propertiesRNA Interference and Gene DeliveryDendrimers and Hyperbranched Polymers

Isothermal crystallization and spherulite structure of partially miscible polypropylene–linear low‐density polyethylene blends

Jun Li、Robert A. Shanks、Long Yu2001-08-10Journal of Applied Polymer Science

Abstract Polypropylene (PP) was blended with a linear low‐density polyethylene (LLDPE, containing 5% hexene comonomer) over a composition range of 10–90% of PP. The crystallization and morphology of the PP–LLDPE blends were studied by differential scanning calorimetry (DSC), polarized optical microscopy with a hot sta…

Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties

Adsorption Configuration and Local Ordering of Silicotungstate Anions on Ag(100) Electrode Surfaces

Lien Lee、Jia X. Wang、Radoslav R. Adžić 等 5 位作者2001-08-10Journal of the American Chemical Society

X-ray reflectivity, cyclic voltammetry, and scanning tunneling microscopy (STM) are used to examine the structure of alpha-SiW12O4(4-) or silicotungstic acid (STA) adsorbed on Ag(100) in acid solution. The voltammetry shows that STA passivates the Ag surface relative to electron transfer to a solution redox species. S…

Metal-Organic Frameworks: Synthesis and ApplicationsPolyoxometalates: Synthesis and ApplicationsVanadium and Halogenation Chemistry

Photochemical Generation of Nitric Oxide from 6-Nitrobenzo[a]pyrene

Kiyoshi Fukuhara、Masaaki Kurihara、Naoki Miyata2001-08-10Journal of the American Chemical Society

Photolabile 6-nitrobenzo[a]pyrene (6-nitroBaP) released nitric oxide (NO) under visible-light irradiation. The generation of NO and the concomitant formation of the 6-oxyBaP radical were confirmed by ESR. BaP quinones were also detected as further oxidized products of the 6-oxyBaP radical. No such photodegradation was…

Photochemistry and Electron Transfer StudiesPhotochromic and Fluorescence ChemistryPhotoreceptor and optogenetics research

Core−Shell Nanostructured Nanoparticle Films as Chemically Sensitive Interfaces

Li Han、David R. Daniel、Mathew M. Maye 等 4 位作者2001-08-10Analytical Chemistry

This paper reports the results of an investigation of vapor molecule sorption at different types of nanostructured nanoparticle films. Core-shell nanoparticles of two different core sizes, AU2-nm and Au5-nm, and molecular linkers of two different binding properties, 1,9-nonanedithiol and 11-mercaptoundecanoic acid, ar…

Gold and Silver Nanoparticles Synthesis and ApplicationsAdvanced biosensing and bioanalysis techniquesMolecular Junctions and Nanostructures

Monte Carlo Simulation of Sinusoidally Modulated Superlattice Growth

H. Jeong、B. Kahng、S. Lee 等 6 位作者2001-08-10arXiv

The fabrication of ZnSe/ZnTe superlattices grown by the process of rotating the substrate in the presence of an inhomogeneous flux distribution instead of successively closing and opening of source shutters is studied via Monte Carlo simulations. It is found that the concentration of each compound is sinusoidally modu…

Materials Science

Low Vπ Electrooptic Modulators from CLD-1: Chromophore Design and Synthesis, Material Processing, and Characterization

Cheng Zhang、Larry R. Dalton、Min‐Cheol Oh 等 5 位作者2001-08-10Chemistry of Materials

A ring-locked, phenyltetraene-based, second-order nonlinear optical chromophore (CLD-1) was synthesized. It shows no drop in decomposition temperature compared to its phenyltriene analogue, while the molecular nonlinearity increases by a factor of 2.25 from 6252 × 10 - 48 to 14065 × 10 - 48 esu at 1.9 μm. Thin films a…

Advanced Fiber Laser TechnologiesNonlinear Optical Materials ResearchNonlinear Optical Materials Studies

Purification and Characterization of Single-Wall Carbon Nanotubes (SWNTs) Obtained from the Gas-Phase Decomposition of CO (HiPco Process)

I. W. Chiang、Bruce E. Brinson、Aaron Y. Huang 等 8 位作者2001-08-10OpenAlex

A purification method is given for extracting the Fe metal catalyst and non-SWNT carbon from nanotubes produced by the HiPco process.(1,2) A multistage purification method has been investigated. Sample purity is documented by ESEM, TEM, TGA, Raman and UV-vis-near-IR spectroscopy. Metal catalyzed oxidation at low tempe…

Carbon Nanotubes in CompositesGraphene research and applicationsNanotechnology research and applications

New Approach To Produce Monosized Polymer Microcapsules by the Solute Co-diffusion Method

Jin Woong Kim、Sung-A Cho、Hak‐Hee Kang 等 7 位作者2001-08-09Langmuir

This study introduces a new approach for producing highly monosized polymer microcapsules. The technique employs an impressive process in which the solute, dissolved freely in a solvent, is diffused uniformly into the preexisting monosized polymer particles in the form of a fine emulsion. The solvent is then eliminate…

Nanoparticle-Based Drug DeliveryAdvanced Polymer Synthesis and CharacterizationOrthopaedic implants and arthroplasty

Electronic excitations investigated by inelastic x-ray scattering spectroscopy

W. Schülke2001-08-09Journal of Physics Condensed Matter

It is shown how non-resonant and resonant inelastic x-ray scattering spectroscopy (IXSS) offer valuable information about electronic excitations in solids. After a presentation of the basic relations, applications of IXSS on a large variety of systems and electronic excitations are discussed, where in most cases synch…

High-pressure geophysics and materialsX-ray Spectroscopy and Fluorescence AnalysisX-ray Diffraction in Crystallography

Crystal Structure−Reactivity Correlation in Single-Crystalline Photochromism of 1,2-Bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene

Taro Yamada、Keishi Muto、Seiya Kobatake 等 4 位作者2001-08-09The Journal of Organic Chemistry

Single-crystalline photochromism of 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene 1a was followed in situ by X-ray crystallographic analysis. The crystal of 1a has two molecules with different conformations in the crystallographic asymmetric unit. The X-ray analysis of the photoirradiated crystal showed th…

Porphyrin and Phthalocyanine ChemistryPhotochromic and Fluorescence ChemistryOrganic Chemistry Cycloaddition Reactions