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Novel synthesis and new chemistry of naphthochlorins

Bénédicte Krattinger、Daniel J. Nurco1998-01-01Chemical Communications

Reactions of 2-nitro-5,10,15,20-tetraphenylporphyrin with alkyl α-isocyanoacetates afford naphthochlorins (in addition to the expected pyrroloporphyrins) which undergo free radical dimerization; the X-ray structure of one such naphthochlorin dimer is reported.

Porphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation MechanismsPorphyrin Metabolism and Disorders

NMR and Raman Studies of Na<sub>2</sub>O-P<sub>2</sub>O<sub>5</sub>-SiO<sub>2</sub> Glasses

Hiroshi Yamashita、Hidetake Yoshino、Keishi Nagata 等 6 位作者1998-01-01Journal of the Ceramic Society of Japan

The 29Si and 31P nuclear magnetic resonance (NMR) chemical shifts and the Qn distribution in ternary sodium phosphosilicate glasses were examined. In the NaPO3-SiO2 glasses, only the Si(Q4) unit from SiO2 and the P(Q2) unit from NaPO3 are observed. When the P2O5 content increases at fixed mole fractions of SiO2 equal…

Glass properties and applicationsPhase-change materials and chalcogenidesSolid-state spectroscopy and crystallography

Surface Modification of Poly(L-lactic acid) Film with Bioactive Materials by a Novel Direct Alkaline Treatment Process.

Tetsuji Yamaoka、Yoshiyuki Takebe、Yoshiharu Kimura1998-01-01KOBUNSHI RONBUNSHU

組織再建術におけるスキャホールドの特性としては, 細胞との良好な付着, 増殖, さらには分化誘導などが要求される. 本研究では, スキャホールドとして最も多く研究されているポリ-L-乳酸 (PLLA) の表面改質を目的として, PLLA表面へのゼラチンの固定化法について検討した. ラジカル開始剤を用いたPLLA-ゼラチン結合反応では十分な固定化量が得られなかったが, アルカリ条件下におけるPLLA-ゼラチン直接固定化法では2μg/cm2のゼラチンの化学的固定化が達成された. 得られたゼラチン固定化PLLAフィルム上において3T3細胞の良好な初期接着が観察され, この直接固定化法がポリ乳酸のバルク特性を変化させることなく, また,…

biodegradable polymer synthesis and propertiesCollagen: Extraction and CharacterizationBiopolymer Synthesis and Applications

Polymer surfaces and interfaces in light-emitting devices

Thomas Kugler、M. Lögdlund、W. R. Salaneck1998-01-01IEEE Journal of Selected Topics in Quantum Electronics

In the context of polymer electronic devices, it is of critical importance to understand the nature of the polymer surfaces and the polymer-electrode interfaces. It has been shown that for conjugated polymers, photoelectron spectroscopy, especially in connection with quantum chemical modeling, provides a maximum amoun…

Organic Electronics and PhotovoltaicsOrganic Light-Emitting Diodes ResearchConducting polymers and applications

Magnetic Properties of 3-(4-R-Phenyl)-1,5-diphenyl-6-oxo- and -thioxoverdazyl Radical Crystals (R = OCH 3 , CH 3 , CN, and NO 2 )

Kazuo Mukai、Masaaki Nuwa、Kentaro Suzuki 等 6 位作者1998-01-01The Journal of Physical Chemistry B

Magnetic susceptibilities of 8 kinds of 3-(4-R-phenyl)-1,5-diphenyl-6-oxo- and -thioxoverdazyl radical crystals ( p -MDpOV (R = OCH 3 ), p -MeDpOV (R = CH 3 ), p -CyDpOV (R = CN), p -NDpOV (R = NO 2 ), p -MDpTV (R = OCH 3 ), p -MeDpTV (R = CH 3 ), p -CyDpTV (R = CN), and p -NDpTV (R = NO 2 )) were measured between 4.2…

Magnetism in coordination complexesOrganic and Molecular Conductors ResearchElectron Spin Resonance Studies

Association of two-coordinate copper(I) complexes: switching on and off Cu···Cu, ligand···ligand and Cu–ligand interactions

Xiangyang Liu1998-01-01Chemical Communications

A combined theoretical ab initio and structural database study is presented of the different interactions that allow two-coordinate copper(I) molecules to associate, from weak interactions to chemical bonds, giving rise to different structures.

Metal complexes synthesis and propertiesMagnetism in coordination complexesMetal-Catalyzed Oxygenation Mechanisms

Pressure Dependence of the Order-to-Disorder Transition in Polystyrene/Polyisoprene and Polystyrene/Poly(methylphenylsiloxane) Diblock Copolymers

Bernd Steinhoff、M. Rüllmann、M. Wenzel 等 11 位作者1998-01-01Macromolecules

The pressure dependence of the order-to-disorder transition in a polystyrene/polyisoprene (PS/PI) ( M = 17 000) and a polystyrene/poly(methylphenylsiloxane) (PS/PMPS) ( M = 29 600) diblock copolymer of symmetric composition has been studied using small-angle X-ray scattering. The order−disorder transition is investiga…

Polymer crystallization and propertiesMaterial Dynamics and PropertiesBlock Copolymer Self-Assembly

An experimental investigation of the intrinsic convection in a sedimenting suspension

Yannick Peysson、Élisabeth Guazzelli1998-01-01Physics of Fluids

The sedimentation of spheres in a Newtonian fluid is experimentally studied under creeping flow conditions. The mean particle settling velocity and the particle velocity fluctuations are measured across the width of the sedimentation cell. We show that there can be a global intrinsic convection of the suspension super…

Material Dynamics and PropertiesTheoretical and Computational PhysicsRheology and Fluid Dynamics Studies

Hydroxylation of alkanes by molecular oxygen with dinuclear FeII macrocyclic complexes as catalysts

Zheng Wang、Arthur E. Martell1998-01-01Chemical Communications

The iron(II) complexes of two new macrocyclic ligands: [24]RBPyBC (L24), a 24-membered macrocycle containing phenol, pyridine and amino donor groups, and [30]RBBPyBC (L30), a 30-membered macrocycle containing phenol, bipyridine, and amino donor groups, were found to be effective for the hydroxylation of alkanes, inclu…

Magnetism in coordination complexesLanthanide and Transition Metal ComplexesMetal-Catalyzed Oxygenation Mechanisms

Intermolecular hydrogen bonding in NLO. Theoretical analysis of the nitroaniline and HF cases

Vicent Moliner、Purificación Escribano、Eduardo Peris1998-01-01New Journal of Chemistry

Monomer and dimer structures of p-nitroaniline have been theoretically optimized both invacuo and in the presence of an electric dipole field by means of abinitio molecular orbital procedures at the Hartree–Fock level of theory with the 6-31G and 6-31+G** basis sets. The electron correlation has been estimated at the…

Nonlinear Optical Materials ResearchMolecular Spectroscopy and StructureChemical synthesis and pharmacological studies

Synthesis and characterization of novel heteropoly-tungstoarsenates containing lanthanides [LnAs4W40O140]25− and their biological activity

Jingfu Liu、Ya-Guang Chen、Lu Meng 等 6 位作者1998-01-01Polyhedron

A series of lanthanide polyoxoanions [LnAs4W40O140]25− (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy or Yb) have been prepared from the cryptate anion [NaAs4W40O140]27− and lanthanides and characterized by elemental analysis, 183W NMR, emission spectra. A number of evidences indicate that the lanthanides occupy the central…

Lanthanide and Transition Metal ComplexesPolyoxometalates: Synthesis and ApplicationsNanocluster Synthesis and Applications

Layer disorder in carbon anodes

Ping Zhou、Roland Lee、Agnès Claye 等 4 位作者1998-01-01Carbon

Inter- and intra-layer disorder in a representative hard carbon derived from epoxy novolac resin at 1000°C have been investigated by comparing both the elastic structure factor S(Q) and radial distribution function obtained from pulsed neutron time-of-flight measurements with calculations from simple hypothetic system…

Carbon Nanotubes in CompositesGraphene research and applicationsFiber-reinforced polymer composites

Metallocene-catalyzed polymers : materials, properties, processing & markets

George M. Benedikt、Brian Goodall1998-01-01Medical Entomology and Zoology

It has been estimated that within just ten years, over half of all polyolefins will be made by using metallocene catalysts. This ground-breaking volume from PDL brings together for the first time work from dozens of world-renowned experts on the subject. Fifty chapters of peer-reviewed content offer insights into appl…

Polymer crystallization and propertiesPolymer Science and PVC

Monitoring scientific developments from a dynamic perspective: Self-organized structuring to map neural network research

Ed Noyons、Anthony F. J. van Raan1998-01-01Journal of the American Society for Information Science

With the help of bibliometric mapping techniques, we have developed a methodology of “self-organized” structuring of scientific fields. This methodology is applied to the field of neural network research. We propose a field-definition based on the present situation. This is done by letting the data themselves generate…

Complex Network Analysis TechniquesMachine Learning in Materials ScienceEcosystem dynamics and resilience

Chapter 5. Charge densities from X-ray diffraction data

Mark A. Spackman1998-01-01Annual Reports Section C (Physical Chemistry)

M. A. Spackman, Annu. Rep. Prog. Chem., Sect. C: Phys. Chem., 1998, 94, 177 DOI: 10.1039/PC094177

Crystallography and molecular interactionsX-ray Spectroscopy and Fluorescence AnalysisX-ray Diffraction in Crystallography

Ecology of siliceous sponges - Application to the environmental interpretation of the Upper Jurassic sponge facies (Oxfodian) from Spain.

Manfred Krautter1998-01-01Journal of iberian geology: an international publication of earth sciences

the major factors controtling [he morphological and taxonomie composition of siliceous sponge faunas are sedimentation rate and nutrient supply. In seawater bacteria are most abundant in the upper par[ of [he water column. Towards greater depths bacteria disappear gradually. The bathymetric distribution of filter-feed…

Diatoms and Algae Research

Atomistic simulation of the effects of calcium and strontium defects on the surface structure and stability of BaSO4

S. E. Redfern、Stephen C. Parker1998-01-01Journal of the Chemical Society Faraday Transactions

BaSO4 (baryte), SrSO4 (celestine) and CaSO4 (anhydrite) were studied using atomistic simulation techniques and their equilibrium morphologies determined from the calculated surface energies. Monolayer and bilayer growth of strontium sulfate or calcium sulfate on barium sulfate were modelled and the calculated surface…

Calcium Carbonate Crystallization and InhibitionMinerals Flotation and Separation Techniquesnanoparticles nucleation surface interactions

The crosslinking mechanism in gamma irradiation of polyarylsulfone: evidence for Y-links

David J. T. Hill、David Lewis、James H. O’Donnell 等 4 位作者1998-01-01Polymers for Advanced Technologies

Measurements of molecular weights, soluble fractions and examination of NMR spectra of bisphenol-A polysulfone, after gamma irradiation in vacuum at 150°C were used to elucidate the mechanism of crosslinking. Excellent agreement was obtained between G(S) and G(X) determined from measurements above and below the gel do…

Polymer Nanocomposites and PropertiesConducting polymers and applicationsPolymer Nanocomposite Synthesis and Irradiation

Porous Silicon Physics and Device Applications: A Status Report

Philippe M. Fauchet、J. von Behren、Karl D. Hirschman 等 5 位作者1998-01-01physica status solidi (a)

Silicon, an indirect gap semiconductor, can emit light with 10% efficiency at room temperature, provided that it is in the form of low-dimensional (quantum dots or wires) nanostructures. Porous silicon is the best known example of such nanostructures. The luminescence mechanisms and the relationship between bandgap en…

Semiconductor materials and devicesSilicon Nanostructures and PhotoluminescenceNanowire Synthesis and Applications