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Synthesis and spectroscopic and magnetic properties of a unique diamagnetic binuclear .mu.-oxo vanadium(IV) complex. Crystal structure of [(tpa)VO(.mu.-O)VO(tpa)](ClO4)2 (tpa = tris(2-pyridylmethyl)amine)

Hans Toftlund、Sine Larsen、Keith S. Murray1991-10-01Inorganic Chemistry

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and spectroscopic and magnetic properties of a unique diamagnetic binuclear .mu.-oxo vanadium(IV) complex. Crystal structure of [(tpa)VO(.mu.-O)VO(tpa)](ClO4)2 (tpa = tris(2-pyridylmethyl)amine)Hans Toftlund, Sine Larsen, and Keith S. MurrayCite this: Inorg. Chem.…

Magnetism in coordination complexesMetal-Catalyzed Oxygenation MechanismsVanadium and Halogenation Chemistry

Absorption spectra of charged oligo (phenylenevinylene)s: On the detection of polaronic and bipolaronic states

R. Schenk、Heike Gregorius、Kläus Müllen1991-10-01Advanced Materials

Communication: The effective conjugation length of poly(phenylenevinylene) an important conducting polymer, can be estimated by extrapolation of the results of UV/VIS/NIR studies of the radical anions and dianions of the soluble, well‐characterized oligo(phenylenevinylene)s shown in the figure. This information, in tu…

Advanced Sensor and Energy Harvesting MaterialsConducting polymers and applicationsAnalytical Chemistry and Sensors

Involvement of GroEL in nif gene regulation and nitrogenase assembly

David Govezensky、Tsvika Greener、Gil Segal 等 4 位作者1991-10-01Journal of Bacteriology

Several approaches were used to study the role of GroEL, the prototype chaperonin, in the nitrogen fixation (nif) system. An Escherichia coli groEL mutant transformed with the Klebsiella pneumoniae nif gene cluster accumulated very low to nondetectable levels of nitrogenase components compared with the isogenic wild-t…

Bacterial Genetics and BiotechnologyEnzyme Structure and FunctionMetalloenzymes and iron-sulfur proteins

Mullite Formation from Nonstoichiometric Diphasic Precursors

Dong X. Li、William Thomson1991-10-01Journal of the American Ceramic Society

Diphasic gels with Al/Si atomic ratios of 6/1, 3.1/1, 3/1, 2/1, and 1/1 were used to study the effect of precursor composition on mullite formation process and the resulting microstructure. Mullite formation initiated at about 1300°C for all samples, with only some slight differences in temperatures. The mullite forma…

Advanced ceramic materials synthesisAluminum Alloys Composites PropertiesIntermetallics and Advanced Alloy Properties

Molecular Dynamics Simulations of Supercooled Liquids near the Glass Transition

Jean‐Louis Barrat、Michael L. Klein1991-10-01Annual Review of Physical Chemistry

Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution and have already been profoundly affected by the application of existing ML ...Read More

Material Dynamics and Properties

On the determination of the Burgers vector of quasicrystal dislocations by transmission electron microscopy

Markus Wollgarten、D. Gratias、Z. Zhang 等 4 位作者1991-10-01Philosophical magazine. A/Philosophical magazine. A. Physics of condensed matter. Structure, defects and mechanical properties

The contrast of dislocations in icosahedral quasicrystals observed by transmission electron microscopy is discussed in the framework of the kinematical theory of electron diffraction. It is found that, owing to the special structural features of dislocations in quasiperiodic lattices, there are two basically different…

Quasicrystal Structures and PropertiesX-ray Diffraction in CrystallographyMineralogy and Gemology Studies

Solubility Limits of α'‐SiAION Solid Solutions in the System Si,Al,Y/N,O

Wei‐Ying Sun、T. Y. Tien、T.S. Yen1991-10-01Journal of the American Ceramic Society

The solubility limit of α'‐SiAION solid solutions on the Si 3 N 4 ─YN:3AIN composition join in the system Si 3 N 4 ─YN─AIN has been determined at 1800°C. The end members of these solid solutions are Y 0.43 Si 10.7 Al 1.3 N 16 and Y 0.8 Si 9.6 Al 2.4 N 16 . Unit‐cell dimensions of the α'‐SiAION solid solutions in the s…

Ferroelectric and Piezoelectric MaterialsAdvanced ceramic materials synthesisMicrowave Dielectric Ceramics Synthesis

Molecular‐Field Theory Analysis of Rare‐Earth Ternary Carbides Derived from R2Fe17 Compounds

W. H. Qiao、Q. Wang、X.P. Zhong 等 4 位作者1991-10-01physica status solidi (b)

Abstract On the basis of a two‐sublattice model, the temperature dependent magnetic properties of the intermetallic compounds R 2 Fe 17 C (R = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Lu) are analyzed using the molecular‐field theory. The results of the analysis show that the molecular‐field coefficients n RF are rather se…

Magnetic properties of thin filmsRare-earth and actinide compoundsMagnetic Properties of Alloys

Combustion of Black Powder. Part III: Hot stage microscopy studies

Ghulam Hussain、Gwilym J. Rees1991-10-01Propellants Explosives Pyrotechnics

Abstract A hot‐stage unit, operating over the temperature range from ambient to 1000°C has been used to study the combustion of black powder. Direct observation of heating of mixtures was supplemented by 35‐mm photomicrography. Results are presented for black powder supplied and mixture prepared in the laboratory.

Combustion and flame dynamicsEnergetic Materials and CombustionThermal and Kinetic Analysis

Property Structure Correlations in Wool Fibers

D. Rama Rao、V. B. Gupta1991-10-01Textile Research Journal

We have compared the mechanical properties of wool fibers from three different breeds of sheep, Lincoln, Chokla, and Merino. The tensile moduli are highest for Lincoln, followed by Chokla and Merino fibers, but there is a reverse trend in the torsional modulus. The differences in mechanical properties are explained in…

Dyeing and Modifying Textile FibersTextile materials and evaluations

Diffraktive Optik: Mikrostrukturen als optische Elemente

K. Knop1991-10-01Physikalische Blätter

Abstract Die Optik gehört zu den ältesten Teilgebieten der Physik und hat zu deren Entwicklung immer wieder entscheidend beigetragen. In der ersten Hälfte dieses Jahrhunderts wurde die Optik durch die aufregenden Entwicklungen in der Quantenmechanik und Elementarteilchenphysik etwas in den Hintergrund (und aus vielen…

Photonic and Optical DevicesPhotonic Crystals and ApplicationsOptical Coatings and Gratings

SEM, EDX and XRD studies of the scales formed on the Fe–Mn–Al–C system in oxidizing–sulphidizing environments

S. C. Tjong1991-10-01X-Ray Spectrometry

Abstract The use of Fe–Mn–Al–C alloys in oxidizing–sulphidizing environments at elevated temperatures is considered. Applications of SEM, EDX mapping and x‐ray diffraction techniques to the microstructural characterization of the scale development on these alloys are reviewed. Combination of the electron microscope an…

Corrosion Behavior and InhibitionMetal and Thin Film MechanicsMetal Alloys Wear and Properties

Raman scattering and lattice-dynamical calculations of alkali-metal sulfates

D. Liu、Hsiao‐Ming Lu、J. R. Hardy 等 4 位作者1991-10-01Physical review. B, Condensed matter

Raman-scattering measurements on single crystals of ${\mathrm{K}}_{2}$${\mathrm{SO}}_{4}$, ${\mathrm{Rb}}_{2}$${\mathrm{SO}}_{4}$, and ${\mathrm{Cs}}_{2}$${\mathrm{SO}}_{4}$ have been made at both room and liquid-nitrogen temperatures. Lattice-dynamical calculations, based on a rigid-ion model using the Gordon-Kim met…

Glass properties and applicationsSpectroscopy and Quantum Chemical StudiesSolid-state spectroscopy and crystallography

L3,2core-hole lifetime widths of 3dtransition metals

Douglas M. Pease1991-10-01Physical review. B, Condensed matter

Transition-metal x-ray-emission spectra, corresponding to transitions between the 3s level and the ${\mathit{L}}_{3,2}$ core holes, are studied. The spectra are synthesized from a superposition of two Lorentzian functions, where the relative weighting of the Lorentzians is calculated based on the assumptions of variou…

X-ray Spectroscopy and Fluorescence AnalysisElectron and X-Ray Spectroscopy TechniquesSurface and Thin Film Phenomena

Phase-transition process of Na2SO4(III) to Na2SO4(I) and anharmonic thermal vibration

Katsufumi Tanaka、Haruhiko Naruse、H. Morikawa 等 4 位作者1991-10-01Acta Crystallographica Section B Structural Science

The crystal structure of Na2SO4(III) (space group Cmcm) and thermal motions of atoms were investigated at 298, 463 and 505 K. The cell parameters are a = 5.6274 (4), b = 8.9664 (11) and c = 6.9737 (9)/~, at 298 K. The R and wR values were 0.0197 and 0.0202 for 984 reflections at 298 K, 0.0201 and 0.0199 for 640 reflec…

Solid-state spectroscopy and crystallographyChemical and Physical Properties in Aqueous SolutionsThermal and Kinetic Analysis

Ion implantation effects in polycrystalline WO3 thin films

T.J. Tate、M.F. Garcia Parajo、Mino Green1991-10-01Journal of Applied Physics

Ion implantation is a possible technique to introduce electrochromically active dopants into fine-grained WO3 thin films. However, to be of use, we must be able to distinguish, and erase, effects due to collisional damage. Argon implants were performed in order to investigate damage effects. Pure damage was found to c…

Gas Sensing Nanomaterials and SensorsAdvanced Memory and Neural ComputingTransition Metal Oxide Nanomaterials

Small-angle X-ray scattering study of lamellar microdomains in a block copolymer

Shinichi Sakurai、Shigeru Okamoto、Tomoaki Kawamura 等 4 位作者1991-10-01Journal of Applied Crystallography

Lamellar microdomains formed in the solvent-cast films of a poly[styrene-block-(ethylene-alt-propylene)] (SEP) diblock polymer were studied by small-angle X-ray scattering (SAXS). The SAXS profiles, displaying a series of peculiar scattering maxima which cannot be ascribed to the higher-order diffraction maxima from a…

Polymer crystallization and propertiesBlock Copolymer Self-AssemblyCopper Interconnects and Reliability

Critical behavior at the nematic–to–smectic-A transition in a nonpolar liquid crystal with wide nematic range

Li Chen、J. D. Brock、Jen‐Yu Huang 等 4 位作者1991-10-01Physical Review Letters

High-resolution x-ray scattering experiments to study the critical smectic-A fluctuations in the nematic phase have been performed on a mixture of two nonpolar, two-benzene-ring compounds. The ratio ${\mathit{T}}_{\mathit{N}\mathit{A}}$/${\mathit{T}}_{\mathit{N}\mathit{I}}$ (=0.885) for this mixture is much smaller th…

Liquid Crystal Research AdvancementsSurfactants and Colloidal SystemsNonlinear Dynamics and Pattern Formation

Detection of Tetrahedral Fe3+ Sites in Nontronite and Vermiculite by Mössbauer Spectroscopy

Vittorio Luca1991-10-01Clays and Clay Minerals

Abstract Mössbauer spectra were obtained for five Ca-exchanged nontronites and one Ca-exchanged vermiculite as the 2-layer hydrates following dehydration at 200°C. Exchange of the samples with Ca 2+ and subsequent dehydration resulted in the appearance of a shoulder at about −0.50 mm/s in the Mössbauer spectra of some…

Soil and Unsaturated FlowClay minerals and soil interactionsIron oxide chemistry and applications

Flow-Through Catalysts for Diesel Engine Emissions Control

Barry Cooper、Stan Roth1991-10-01Platinum Metals Review

Preview this article: Flow-Through Catalysts for Diesel Engine Emissions Control, Page 1 of 1 < Previous page | Next page > /docserver/preview/fulltext/pmr/35/4/pmr0035-0178-1.gif

Catalytic Processes in Materials ScienceCatalysts for Methane ReformingCatalysis and Hydrodesulfurization Studies