Torgil R. Vangberg、Abhik Ghosh1999-12-01Journal of the American Chemical Society
Using nonlocal density functional theory calculations, we have examined several factors influencing ruffling deformations of porphyrin and porphyrazine complexes. Because a ruffling distortion is often a direct result of a small macrocycle core size, which, in turn, is brought about by complexation of a central ion wi…
Molecular Sensors and Ion DetectionPorphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation Mechanisms
Nagao Kobayashi、Ryuji Higashi、Bruno C. Titeca 等 5 位作者1999-12-01Journal of the American Chemical Society
Phthalocyanines with two and four optically active binaphthyl units have been synthesized and characterized by electronic absorption, CD, and MCD spectroscopy. The chiral substituents induce CD in the in-plane polarized Q and Soret bands of phthalocyanines: phthalocyanines having R and S binaphthyls show positive and…
Magnetism in coordination complexesPorphyrin and Phthalocyanine ChemistrySynthesis and Properties of Aromatic Compounds
Heinrich M. Köster、U. Ehrlicher、H. Albert Gilg 等 6 位作者1999-12-01Clay Minerals
Abstract Five Fe–bearing dioctahedral smectites (three nontronites and two Fe-rich smectites) were purified using a variety of physical and chemical procedures. The structural formulae indicate one nontronite and one Fe-rich smectite to be montmorillonitic, whereas the other three smectites are beidellitic. Mössbauer…
Geological and Geochemical AnalysisClay minerals and soil interactionsIron oxide chemistry and applications
R. Murat Tabanli、N.K. Simha、B. T. Berg1999-12-01Materials Science and Engineering A
Fatigue properties of shape-memory alloys (SMA) play an important role in actuator and certain biomedical applications. Since a small cyclic stress can trigger martensitic transformation when the mean stress is close to a critical stress, it is crucial to understand the effect of mean stress. This paper examines mean…
Shape Memory Alloy Transformations
Konstantinos P. Kitsopoulos1999-12-01Clays and Clay Minerals
Abstract The ammonium acetate saturation (AMAS) method was used to study the cation-exchange capacity (CEC) of zeolitic volcaniclastic materials from Santorini and Polyegos Islands, Greece. The AMAS method was tested with respect to the time required to saturate the samples of zeolites with ammonium (NH 4 + ) ions, th…
Zeolite Catalysis and SynthesisClay minerals and soil interactionsChemical Synthesis and Characterization
Clemens Burda、Stephan Link、T. C. Green 等 4 位作者1999-12-01The Journal of Physical Chemistry B
The power dependence of the transient absorption spectrum of CdSe nanoparticle colloids with size distribution of 4.0 ± 0.4 nm diameter is studied with femtosecond pump−probe techniques. At the lowest pump laser power, the absorption bleaching (negative spectrum) characteristic of the exciton spectrum is observed with…
Gold and Silver Nanoparticles Synthesis and ApplicationsQuantum Dots Synthesis And PropertiesChalcogenide Semiconductor Thin Films
Jennifer A. Garlitz、Catherine A. Summers、Robert A. Flowers 等 4 位作者1999-12-01Acta Crystallographica Section D Biological Crystallography
Ethylammonium nitrate (EAN) is a liquid organic salt that has many potential applications in protein chemistry. Because this solvent has hydrophobic and ionic character as well as the ability to hydrogen bond, it is especially well suited for broad use in protein crystallography. For example, EAN may be used as an add…
Protein Structure and DynamicsEnzyme Structure and FunctionBiochemical and Molecular Research
G. PARRISH1999-12-01ASM International eBooks
Carburizing: Microstructures and Properties explains how to recognize and address problems associated with case carburizing treatments for steels. It examines the nature of internal oxidation, decarburization, free carbides, and retained austenite and their effect on fatigue and fracture strength, wear resistance, imp…
Microstructure and Mechanical Properties of SteelsSurface Treatment and Residual StressMetal Alloys Wear and Properties
M. Nespolo、Giovanni Ferraris、Haruo Ohashi1999-12-01Acta Crystallographica Section B Structural Science
The charge distribution (CD) method, previously introduced as a development of the bond-valence (BV) approach, is applied for the first time to mineral structures, and specifically to pyroxenes. CD essentially involves the distribution of the Effective Coordination Number (ECoN) of a cation among all the neighboring a…
High-pressure geophysics and materialsCrystallography and molecular interactionsX-ray Diffraction in Crystallography
Antonio Magurno1999-12-01Die Angewandte Makromolekulare Chemie
This paper gives a brief status of the state of the art of the use of plastic/vegetable fibre composite materials for interior car parts and the technologies to realise such parts (injection moulding, low pressure injection moulding, thermoforming, thermocompression and co-injection moulding). The development activity…
Natural Fiber Reinforced Composites
John R. Sowerby、Hans Keppler1999-12-01American Mineralogist
Near-IR spectra obtained from hydrous silicate melts, close to natural rhyolite, were acquired at both high temperature using a heating stage and simultaneously at high pressure and temperature using a hydrothermal diamond cell. The temperature dependence of the extinction coefficients for the peaks due to OH and H 2…
Zeolite Catalysis and SynthesisMaterial Dynamics and PropertiesGlass properties and applications
Suna Balcı1999-12-01Clay Minerals
Abstract Due to its channels of molecular dimensions and a high specific surface area, sepiolite has many industrial applications which require high resistance to thermal effects in addition to a large surface area. On heating, sorbed water molecules are removed causing changes in the pore size distribution. In this s…
Glass properties and applicationsSoil and Unsaturated FlowClay minerals and soil interactions
George Floudas、C. Gravalides、Thomas Reisinger 等 4 位作者1999-12-01The Journal of Chemical Physics
We report on the effect of pressure on the relaxation modes of the type-A polymer polyisoprene as a function of the chain length for M/Me ratio’s (Me is the entanglement molecular weight): 15, 12, 23, 2, and 5. We find that the spectral shape of the segmental and normal modes is invariant under temperature (T) and pre…
Liquid Crystal Research AdvancementsPolymer crystallization and propertiesMaterial Dynamics and Properties
Zeev Gross、Santiago Ini1999-12-01Organic Letters
A new member of our D 2 symmetry ruthenium porphyrins is shown to be a most selective catalyst for asymmetric epoxidation of terminal and trans -disubstituted olefins. The same catalyst displays some selectivity in kinetic resolution of secondary alcohols and in what appears to be the first example of catalytic enanti…
Porphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation MechanismsATP Synthase and ATPases Research
Marc Durand、G. Martinoty、D. Langévin1999-12-01Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics
The velocity of gravity-driven flow through aqueous foams (forced drainage) has been determined by using electrical conductivity measurements in foams made with solutions of different surfactants. There is always a scaling behavior (power law) between the drainage velocity V and the imposed flow rate Q: V approximatel…
Enhanced Oil Recovery TechniquesPickering emulsions and particle stabilizationFluid Dynamics and Thin Films
Philip J. Camp、Michael P. Allen、Andrew J. Masters1999-12-01The Journal of Chemical Physics
Fluids of hard bent-core molecules have been studied using theory and computer simulation. The molecules are composed of two hard spherocylinders, with length-to-breadth ratio L/D, joined by their ends at an angle 180°−γ. For L/D=2 and γ=0,10,20°, the simulations show isotropic, nematic, smectic, and solid phases. For…
Liquid Crystal Research AdvancementsMaterial Dynamics and PropertiesSurfactants and Colloidal Systems
B. Harte、I. C. W. Fitzsimons、Jeff W. Harris 等 4 位作者1999-12-01Mineralogical Magazine
Abstract Secondary ion mass spectrometry (SIMS) techniques have been used to study the variation of C isotope ratio and N abundance within selected diamonds in relation to their crystal growth zones. The growth zones are seen in cathodoluminescence (CL), and include both octahedral and cuboid zones within typical diam…
High-pressure geophysics and materialsDiamond and Carbon-based Materials ResearchIon-surface interactions and analysis
Paul A. Cameron、Dhanjay Jhurry、V.C. Gibson 等 6 位作者1999-12-01Macromolecular Rapid Communications
The Schiff-base aluminium complex [5-Cl-salen]AlOMe (2) is shown to be a room temperature initiator for controlled ring-opening polymerization of D,L- and L-lactides; the molecular structure of the precursor [5-Cl-salen]AlMe (1) reveals a distorted trigonal bipyramidal geometry.
Organometallic Complex Synthesis and Catalysisbiodegradable polymer synthesis and propertiesCarbon dioxide utilization in catalysis
Ravindra Pandey、Julian D. Gale、Suresh K. Sampath 等 4 位作者1999-12-01Journal of the American Ceramic Society
Stoichiometric zinc aluminate (ZnAl 2 O 4 ) and zinc gallate (ZnGa 2 O 4 ) are simulated in the framework of the shell model, for which a new set of two‐body interatomic potential parameters has been developed. Using these parameters, a reasonable prediction is made for elastic and dielectric constants of ZnAl 2 O 4 a…
Luminescence Properties of Advanced MaterialsAdvanced ceramic materials synthesisMicrowave Dielectric Ceramics Synthesis
Dong‐Pyo Kim、Kyo‐Tae Moon、Joong‐Gon Kho 等 6 位作者1999-12-01Polymers for Advanced Technologies
During the solution reaction of NaBH4/(NH4)2SO4 in tetraglyme to form borazine, polymeric aminoborane (NH2BH2)x has been isolated as a white powder. The powder was characterized by thermal gravimetric analysis/differential scanning calorimetry, infrared and mass spectroscopies, and powder X-ray diffraction. Solid-stat…
Hydrogen Storage and MaterialsBoron and Carbon Nanomaterials ResearchMXene and MAX Phase Materials