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Generalized Fibonacci superlattices, dynamical trace maps, and magnetic excitations

M. Kolá、Mazhar Ali1989-01-01Physical review. B, Condensed matter

Long-wavelength magnetic excitations are investigated in the quasiperiodic layered structures consisting of alternating magnetic and nonmagnetic layers, distributed according to the recently introduced generalized Fibonacci sequences. Both periodic and real boundary conditions are used. Spin-wave spectra for Fibonacci…

Theoretical and Computational PhysicsQuasicrystal Structures and PropertiesAdvanced Mathematical Theories and Applications

Synthesis of a cyclic porphyrin trimer with a semi-rigid cavity

Harry L. Anderson、Jeremy K. M. Sanders1989-01-01Journal of the Chemical Society Chemical Communications

A cyclic trinuclear porphyrin host has been synthesised; its binding properties show that it has a spacious cavity which prefers an open conformation but which can close around small bidentate ligands such as 4,4′-bipyridyl.

Supramolecular Chemistry and ComplexesPorphyrin and Phthalocyanine ChemistryPorphyrin Metabolism and Disorders

From laterally branched mesogens to novel twin molecules

W. Weißflog、D. Demus、Siegmar Diele 等 5 位作者1989-01-01Liquid Crystals

Extending a design concept for liquid-crystalline compounds with large lateral substituents, we have synthesized several new variants of twin compounds: lateral-terminal flexible bound, and lateral-lateral flexible bound with and without ring systems in the flexible spacer. X-ray investigations of the nematic phases o…

Liquid Crystal Research AdvancementsPhotonic Crystals and ApplicationsPlant Reproductive Biology

Charge transport in conducting polymers

Siegmar Roth、H. Bleier、W. Pukacki1989-01-01Faraday Discussions of the Chemical Society

Experimental data on the electrical conductivity of conducting polymers is reviewed. Polyacetylene is regarded as a prototype and the conductivity is studied as a function of doping level, temperature, frequency and conjugation length. The consistency of the data with a model of anisotropic variable range hopping is p…

Conducting polymers and applicationsElectrochemical Analysis and ApplicationsAnalytical Chemistry and Sensors

Liquid Crystal Polymers. XI. Liquid Crystal Aromatic Polyesters: Early History and Future Trends

W. J. Jackson1989-01-01Molecular Crystals and Liquid Crystals Incorporating Nonlinear Optics

This brief history and review of liquid crystalline polyesters (LCPs) is limited to all-aromatic LCPs except for a description of the discovery of the first thermotropic polymer to be injection molded or melt spun and characterized as being liquid crystalline: an Eastman PET/PHB (p-hydroxybenzoic acid) copolyester (fi…

Liquid Crystal Research AdvancementsSynthesis and Properties of Aromatic CompoundsSynthesis and properties of polymers

Microencapsulation using Poly(L-Lactic Acid) I: Microcapsule Properties Affected by the Preparative Technique

R. Jalil、J. R. Nixon1989-01-01Journal of Microencapsulation

Microcapsules were prepared using a poly (L-lactic acid) (L = PLA), mol. wt. 43,200, by an emulsification and solvent evaporation technique. Phenobarbitone (PB) was used as a reference drug, (core to polymer ratio, 1:1). Both the o/w and w/o emulsion system were investigated in order to study microcapsule properties a…

Advanced Polymer Synthesis and Characterizationbiodegradable polymer synthesis and propertiesAdvanced Drug Delivery Systems

Formation of electronically conductive thin films of metal phthalocyanines via electropolymerization

Huawen Li、Thomas F. Guarr1989-01-01Journal of the Chemical Society Chemical Communications

Oxidative electropolymerization of cobalt and nickel complexes of tetra-aminophthalocyanine in dimethyl sulphoxide rapidly leads to electrode modification, and the thin polymeric coatings obtained by this method are highly electronically conductive under a wide variety of conditions.

Conducting polymers and applicationsPorphyrin and Phthalocyanine ChemistryElectrochemical Analysis and Applications

The Hot Pressing of Dry-formed Wood-based Composites. Part II. A Simulation Model for Heat and Moisture Transfer, and Typical Results

Philip E. Humphrey1989-01-01Holzforschung

Article The Hot Pressing of Dry-formed Wood-based Composites. Part II. A Simulation Model for Heat and Moisture Transfer, and Typical Results was published on January 1, 1989 in the journal Holzforschung (volume 43, issue 3).

Natural Fiber Reinforced CompositesAdditive Manufacturing and 3D Printing TechnologiesHygrothermal properties of building materials

Steric Modulation of the Porphycene System by Alkyl Substituents: 9,10,19,20‐Tetraalkylporphycenes

Emanuel Vogel、Matthias Köcher、Johann Lex 等 4 位作者1989-01-01Israel Journal of Chemistry

Abstract Porphycene ( 2 ), a planar structural isomer of porphyrin ( 1 ) recognized and synthesized only recently, exhibits short N … N distances allowing exceptionally strong N‐H … N hydrogen bonds to be formed. Although the N 4 ‐coordination hole of 2 is smaller than that of 1 , the new tetrapyrrolic macrocycle is c…

Supramolecular Chemistry and ComplexesPorphyrin and Phthalocyanine ChemistrySurface Chemistry and Catalysis

New Decagonal Al–Ni–Fe and Al–Ni–Co Alloys Prepared by Liquid Quenching

A.‐P. Tsai、Akihisa Inoue、Tsuyoshi Masumoto1989-01-01Materials Transactions JIM

New decagonal alloys in the Al–Ni–Fe and Al–Ni–Co systems have been produced by liquid quenching. Their formations extend in the ranges of 9 to 16 at% Ni and 9 to 21 at% Fe or Co. The whole replacement of Fe or Co in Al75Ni10(Fe or Co)15 alloys by V, Cr, Mn or Ru gives a mixed structure consisting of decagonal, icosah…

Microstructure and mechanical propertiesMetallic Glasses and Amorphous AlloysQuasicrystal Structures and Properties

An asymptotic description of transient settling and ultrafiltration of colloidal dispersions

K. E. Davis、William B. Russel1989-01-01Physics of Fluids A Fluid Dynamics

Sedimentation and ultrafiltration are important processes for removing solids from suspensions. The Kynch theory describes the transient settling of noncolloidal particles forming an incompressible sediment by providing a solution to the convective conservation equation. This solution predicts the existence of several…

Material Dynamics and PropertiesCoagulation and Flocculation StudiesRheology and Fluid Dynamics Studies

A Stable Decagonal Quasicrystal in the Al–Cu–Co System

A.‐P. Tsai、Akihisa Inoue、Tsuyoshi Masumoto1989-01-01Materials Transactions JIM

The structure and growth morphology of Al65Cu15Fe20−xCox and Al65Cu20Fe15−xCox alloys have been examined in rapidly solidified, conventionally solidified and fully annealed states. A conventionally solidified Al65Cu15Co20 alloy, which was prepared by the whole substitution of Fe by Co for a stable icosahedral Al65Cu20…

Quasicrystal Structures and PropertiesMineralogy and Gemology Studies

Comparison of the Ar(3P2) and Ar(3P) reactions with chlorine and fluorine containing molecules: Propensity for ion–core conservation

N. Sadeghi、M. Cheaib、D. W. Setser1989-01-01The Journal of Chemical Physics

Optical pumping has been used to select Ar atoms in the metastable 3P2 or 3P0 state in a flowing afterglow reactor. The relative concentrations of the two metastable states were assigned from observation of the N2(C,v′) emission spectra. The isolated reactions of the Ar(3P2) and Ar(3P0) atoms with F2, NF3, Cl2, CCl4,…

Catalytic Processes in Materials ScienceMass Spectrometry Techniques and ApplicationsAmmonia Synthesis and Nitrogen Reduction

The tetranuclear cluster Fe III [Fe III (salicylhydroximato)(MeOH)(acetate)]3 is an analogue of M3+(9-crown-3)

Myoung Soo Lah、Martin L. Kirk、William Hatfield 等 4 位作者1989-01-01Journal of the Chemical Society Chemical Communications

The first example of transition metal co-ordination to ethereal like oxygens of a 9-metallocrown-3 ether is seen in FeIII[FeIII(salicylhydroximato)(MeOH)(acetate)]3 and leads to an unusual tetranuclear cluster which exhibits both inter- and intra-cluster antiferromagnetic interactions and an S= 5 ground state.

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

Some New Observations on Methanol Oxidation Chemistry

T.S. Norton、Frederick L. Dryer1989-01-01Combustion Science and Technology

New experiments conducted in a turbulent flow reactor show kinetic characteristics of methanol oxidation that have not been observed previously. Data are presented for methanol oxidation at equivalence ratios in the range of 0.6−1.6 and initial temperatures or 1025-1090 K at atmospheric pressure. At intermediate exten…

Catalytic Processes in Materials ScienceCatalysis and Oxidation ReactionsHeat transfer and supercritical fluids

Layered Structure of Cast Titanium Surface

Osamu Miyakawa、Kouichi Watanabe、Seigo Okawa 等 6 位作者1989-01-01Dental Materials Journal

The present study concerns the surface layered structure of the cast Ti. A commercial Ti was cast into a mold which was made of a phosphate-bonded Al2O3/SiO2 investment. Elemental analyses of the interfacial zone of the casting were made under an electron probe micro-analyzer. The interfacial zone was composed of four…

Material Properties and ApplicationsLaser and Thermal Forming Techniques

Protein phosphorylation and allosteric control of inducer exclusion and catabolite repression by the bacterial phosphoenolpyruvate: sugar phosphotransferase system.

Milton H. Saier1989-01-01Microbiological Reviews

The bacterial phosphotransferase system (PTS) functions in a variety of regulatory capacities. One of the best characterized of these is the process by which the PTS regulates inducer uptake and catabolite repression. Early genetic and physiological evidence supported a mechanism whereby the phosphorylation state of a…

Bacterial Genetics and BiotechnologyEnzyme Structure and FunctionMachine Learning in Bioinformatics

Modification of the structure and electrochemical properties of poly(thiophene) by ether groups

Jean Roncali、Robert Garreau、Didier Delabouglise 等 5 位作者1989-01-01Journal of the Chemical Society Chemical Communications

Poly[3-(3,6-dioxaheptyl)thiophene] has been synthesised by electropolymerisation; this highly conducting electroactive polymer exhibits specific interactions with lithium cations.

Conducting polymers and applicationsInorganic and Organometallic ChemistrySynthesis and properties of polymers

Invited Lecture. Columnar ordering as an excluded-volume effect

Daan Frenkel1989-01-01Liquid Crystals

The nature of the possible liquid-crystalline phases that a molecular or colloidal system may exhibit depends sensitively on the shape of the constituent particles. Recent computer simulations on fluids of consisting of non-spherical hard-core molecules suggest that, in order to predict the relative stability of isotr…

Liquid Crystal Research AdvancementsMaterial Dynamics and PropertiesMolecular spectroscopy and chirality