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Cruciform porphyrin pentamers

M. Graça H. Vicente、Mark T. Cancilla、Carlito B. Lebrilla 等 4 位作者1998-01-01Chemical Communications

Cruciform porphyrin pentamers 15 and 16 are obtained in good yield by acid-catalyzed tetramerization of ZnII–pyrroloporphyrin 14, followed by oxidation with DDQ; pyrroloporphyrins are in turn obtained from the corresponding pyrrolochlorins by Diels–Alder type reactions of porphyrins involving thermal extrusion of sulf…

Porphyrin and Phthalocyanine ChemistrySurface Chemistry and CatalysisOrganic Chemistry Cycloaddition Reactions

Synthesis of porous yttrium aluminium oxide templated by dodecyl sulfate assemblies

Mitsunori Yada、Masahumi Ohya、Masato Machida 等 4 位作者1998-01-01Chemical Communications

An yttrium aluminium oxide dodecyl sulfate mesophase with a hexagonal structure has been synthesized by a homogeneous precipitation method using urea and was converted into a porous material with a specific surface area of 662 m2 g–1 by anion exchange of the surfactant with acetate ion.

Mesoporous Materials and CatalysisPolyoxometalates: Synthesis and ApplicationsLayered Double Hydroxides Synthesis and Applications

Versatile optical materials: fluorescence, non-linear optical and mesogenic properties of selected 2-pyrazoline derivatives

Joaquín Barberá、Koen Clays、Raquel Giménez 等 6 位作者1998-01-01Journal of Materials Chemistry

A study of the structure-property relationships in a series of 3-(4-n-decyloxyphenyl)-1-(p-X-phenyl)-2-pyrazolines has been performed. By simply changing the substituent in the 1-phenyl ring we were able to tune the physical properties of the compounds. If this ring is non-substituted or substituted with a 4-methoxy,…

Nonlinear Optical Materials ResearchNonlinear Optical Materials StudiesChemical synthesis and pharmacological studies

Molecular dynamics and crystallization behaviour of isopentyl cyanobiphenyl as studied by dielectric relaxation spectroscopy

Maria Massalska-Arodź、Graham Williams、Ian K. Smith 等 6 位作者1998-01-01Journal of the Chemical Society Faraday Transactions

Isopentyl cyanobiphenyl may be cooled into the supercooled liquid state, forming a glass below 210 K. On heating the glass, the supercooled liquid crystallizes above 245 K. Dielectric relaxation spectroscopy (DRS) has been used in the frequency range 10−1 to 105 Hz to study (i) the reorientational motions of the molec…

Liquid Crystal Research AdvancementsMaterial Dynamics and PropertiesThermodynamic properties of mixtures

Composition modulation of catalytic reactors

P.L. Silverston1998-01-01Medical Entomology and Zoology

1. Combustion 2. Co-oxidation 3. Reduction of Nitrogen Oxides 4. Hydrogenation Reactions 5. SO2 Oxidation 6. Miscellaneous Single Reactions 7. Catalytic Gas-Solid Reactions 8. Hydrocarbon Dehyrodgenation and Partial Oxidation 9. Fischer-Tropsch Synthesis 10. Application to Mechanistic Studies 11. Automotive Exhaust Ca…

Catalytic Processes in Materials ScienceCatalysis and Hydrodesulfurization StudiesCatalysis and Oxidation Reactions

Improving endothelial cell adhesion to vascular graft surfaces: Clinical need and strategies

Vinayak Bhat、Bruce Klitzman、Kim E. Koger 等 5 位作者1998-01-01Journal of Biomaterials Science Polymer Edition

Synthetic vascular grafts do not spontaneously endothelialize in humans and require some form of anticoagulation to maintain patency. Preseeding synthetic graft materials such as expanded polytetrafluoroethylene (ePTFE) and polyethylene terephthalate (PET) with endothelial cells (EC) has been examined in various in vi…

Protease and Inhibitor MechanismsElectrospun Nanofibers in Biomedical ApplicationsPolymer Surface Interaction Studies

A grid search procedure of positioning a known molecule in an unknown crystal structure with the use of powder diffraction data

作者信息未提供1998-01-01Zeitschrift für Kristallographie - Crystalline Materials

Abstract An efficient grid search procedure successfully applied to the solution of three unknown molecular structures from X-ray and neutron powder diffraction data is presented.

High-pressure geophysics and materialsCrystallography and molecular interactionsX-ray Diffraction in Crystallography

Formation and annihilation of a bond defect in silicon: Anab initioquantum-mechanical characterization

Fausto Cargnoni、Carlo Gatti、Luciano Colombo1998-01-01Physical review. B, Condensed matter

The electronic structure and bond properties of a lattice defect in silicon formed by the incomplete recombination of a vacancy-interstitial pair are described by combining tight-binding molecular-dynamics and ab initio Hartree-Fock calculations. The defect structure consists of a large nuclear distortion nearly perfe…

Advanced Chemical Physics StudiesGraphene research and applicationsBoron and Carbon Nanomaterials Research

Morphology and Crystallography of α Precipitates in β Ti–Mo Binary Alloys

Tadashi Furuhara、Takehiko Makino、Y. Idei 等 6 位作者1998-01-01Materials Transactions JIM

The morphology and crystallography of α(hcp) precipitates formed in the β(bcc) matrix were examined in the Ti–Mo binary alloys with various Mo contents below the currently proposed monotectoid temperature by means of transmission electron microscopy.In the Ti-10, 20 and 30 mass%Mo alloys, α precipitates form on β grai…

Intermetallics and Advanced Alloy PropertiesTitanium Alloys Microstructure and PropertiesAdvanced materials and composites

Soft X-ray Beamline Specialized for Actinides and Radioactive Materials Equipped with a Variably Polarizing Undulator

Akinari Yokoya、T. Sekiguchi、Y. Saitoh 等 14 位作者1998-01-01Journal of Synchrotron Radiation

This report presents the design of an undulator beamline at SPring-8 to be used for soft X-ray spectroscopy focused on radioactive materials. Photoemission spectroscopy experiments are carried out in a radioisotope (RI)-controlled area where actinide compounds as well as unsealed radioactive materials are usable. Intr…

X-ray Spectroscopy and Fluorescence AnalysisNuclear Physics and ApplicationsElectron and X-Ray Spectroscopy Techniques

Mean atomic number and backscattered electron coefficient calculations for some materials with low mean atomic number

Peter Howell、K. M. W. Davy、A. Boyde1998-01-01Scanning

Abstract In modelling electron backscattering from solids using Monte Carlo simulations, knowledge of mean atomic number, mean atomic weight, and density of the bulk material are required. We studied four different ways in common useforthe calculation of mean atomic number. An alternative and improved approach is to c…

X-ray Spectroscopy and Fluorescence AnalysisMachine Learning in Materials ScienceElectron and X-Ray Spectroscopy Techniques

Solid state coordination chemistry of the copper cyanide–organoamine system: hydrothermal syntheses and structural characterization of [{Cu2(bpy)2(CN)}Cu5(CN)6] and [Cu4(CN)4(biquin)]

D.J. Chesnut1998-01-01Chemical Communications

The hydrothermal reactions of CuCN and Cu(NO3)2·2.5H2O with the appropriate organonitrogen ligand in water yielded a one-dimensional chain, [Cu4(CN)4(biquin)] 1, and a material with a two-dimensional anionic honeycomb network and interpenetrating binuclear cations, [{Cu2(bpy)2(CN)}Cu5(CN)6] 2.

Metal-Organic Frameworks: Synthesis and ApplicationsMagnetism in coordination complexesPorphyrin and Phthalocyanine Chemistry

Preparation of transparent mesoporous silica films by a rapid solvent evaporation method

Hayato Ishikawa、Takaaki Kikuchi1998-01-01Journal of Materials Chemistry

Thin films of silica-alkyltrimethylammonium (alkyl=decyl, dodecyl, tetradecyl, hexadecyl and octadecyl) chloride mesostructured materials are synthesized by spin coating the precursor solutions containing prehydrolyzed tetramethoxysilane and alkyltrimethylammonium salts. The films have been converted to transparent po…

Catalytic Processes in Materials ScienceMesoporous Materials and CatalysisAerogels and thermal insulation

Surface characteristics and biocompatibility of lactide-based poly(ethylene glycol) scaffolds for tissue engineering

Dong Keun Han、Ki Dong Park、Jeffrey A. Hubbell 等 4 位作者1998-01-01Journal of Biomaterials Science Polymer Edition

Novel lactide-based poly(ethylene glycol) (PEG) polymer networks (GL9-PEGs) were prepared by UV copolymerization of a glycerol-lactide triacrylate (GL9-Ac) with PEG monoacrylate (PEG-Ac) to use as scaffolds in tissue engineering, and the surface properties and biocompatibility of these networks were investigated as a…

Bone Tissue Engineering Materialsbiodegradable polymer synthesis and propertiesPolymer Surface Interaction Studies

Volume average demagnetizing tensor of rectangular prisms

Hiroshi Fukushima、Y. Nakatani、N. Hayashi1998-01-01IEEE Transactions on Magnetics

An exact analytic formula is presented for the magnetostatic field produced by a three-dimensional array of uniformly magnetized rectangular prisms. It is derived from the volume integration of a point-function demagnetizing tensor. The values of the point-function demagnetizing tensor at the centers of rectangular pr…

Physics of Superconductivity and MagnetismMagnetic properties of thin filmsMagnetic Properties and Applications

One-pot electrochemical formation of meso,meso-linked porphyrin arrays

Takuji Ogawa、Takuji Ogawa、Yoshihiro Nishimoto 等 6 位作者1998-01-01Chemical Communications

Electrochemical oxidation of [5,15-bis(3,5-di-tert-butylphenyl)porphyrinato]zinc(II) 1, [5,15-bis(4-methoxycarbonylphenyl)porphyrinato]zinc(II), [5,15-bis(pentafluorophenyl)porphyrinato]zinc(II) or [10-bromo-5,15- diphenylporphyrinato]zinc(II) in benzonitrile using a platinum net as the working electrode afforded the…

Electrochemical sensors and biosensorsPorphyrin and Phthalocyanine ChemistryLuminescence and Fluorescent Materials

Organophosphoryl derivatives of trivacant tungstophosphates of general formula α-A-[PW9O34(RPO)2]5−: synthesis and structure determination by multinuclear magnetic resonance spectroscopy (31P, 183W) ‡

Cédric R. Mayer、René Thouvenot1998-01-01Journal of the Chemical Society Dalton Transactions

In the presence of NBun4Br acting as phase-transfer reagent, organophosphonic acids RPO(OH)2 reacted in acetonitrile with the trivacant tungstophosphate sodium salt β-A-Na8[HPW9O34]·24H2O to give hybrid organophosphoryl polyoxotungstate derivatives α-A-[NBun4]3Na2[PW9O34(RPO)2] (R = Et 1, Bun 2, But 3, allyl 4 or Ph 5…

Metal-Organic Frameworks: Synthesis and ApplicationsPolyoxometalates: Synthesis and ApplicationsChemical Synthesis and Characterization

Macromolecular tetrathiafulvalene chemistry

Martin R. Bryce、Wayne Devonport、Leonid M. Goldenberg 等 4 位作者1998-01-01Chemical Communications

Recent developments in the functionalisation of tetrathiafulvalene (TTF) have enabled TTF units to be covalently linked into macromolecular systems. Convergent syntheses of dendrimers containing TTF units are presented, including a (TTF)13 system in which TTF units are emplaced at all layers of the structural hierarch…

Magnetism in coordination complexesOrganic and Molecular Conductors ResearchOrganometallic Compounds Synthesis and Characterization

Photochemical Phase Transition Behavior of Polymer Azobenzene Liquid Crystals with Electron-Donating and -Accepting Substituents at the 4,4‘-Positions

Osamu Tsutsumi、Takashi Kitsunai、Akihiko Kanazawa 等 5 位作者1998-01-01Macromolecules

Photochemical phase transition behavior of polymer liquid crystals (LCs) with donor−acceptor azobenzene moieties which contain both electron-donating and -accepting substituents at the 4,4‘-positions has been explored. Polymer azobenzene LCs were prepared which show nematic (N) LC behavior in the trans form but no LC…

Liquid Crystal Research AdvancementsSurfactants and Colloidal SystemsPhotochromic and Fluorescence Chemistry