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Electronic Structure of Luminescent d0 Niobium and Tantalum Imido Compounds cis,mer-M(NR)Cl3L2

D.S. Williams、Andrey V. Korolev1998-07-01Inorganic Chemistry

Electronic absorption and emission spectra are reported for luminescent d(0) monoimido group 5 compounds M(NR)Cl(3)L(2) (M = Nb, Ta; R = alkyl, aryl; L = dme, Cl(-), py). These compounds display weak (epsilon < 200 M(-)(1) cm(-)(1)), well-resolved lowest-energy transitions in the high-energy visible and near-UV region…

Organometallic Complex Synthesis and CatalysisMagnetism in coordination complexesLanthanide and Transition Metal Complexes

Evaluation of trifluoroiodomethane as SiO2 etchant for global warming reduction

Francesco Fracassi、Rocco D’Agostino1998-07-01Journal of Vacuum Science & Technology B Microelectronics and Nanometer Structures Processing Measurement and Phenomena

The utilization of CF3I in the plasma assisted dry etching of SiO2 has been studied in order to reduce the environmental impact of microelectronics device fabrication. The results show that CF3I is a promising substitute of CF4 in oxide etching since its utilization reduces 3–3.5 times the contribution to the global w…

ZnO doping and propertiesGaN-based semiconductor devices and materialsGas Sensing Nanomaterials and Sensors

Synthesis and optical properties of polyurethanes containing a highly NLO active chromophore

Han Young Woo、Hong‐Ku Shim、Kwang-Sup Lee1998-07-01Macromolecular Chemistry and Physics

Two types of new polyurethanes with a highly NLO active chromophore, 2-[4-[4-[bis(2-hydroxyethyl)amino]phenylazo]benzylidene]malonitrile (HAPM), in the polymer side chain were synthesized (PU1-DCN and PU2-DCN) and characterized. The diisocyanate components of the polymers are 2,4-tolylene diisocyanate and 3,3′-dimetho…

Nonlinear Optical Materials ResearchSynthesis and properties of polymers

Retention of Phosphate by Hydroxyaluminosilicate‐ and Hydroxyaluminum‐Montmorillonite Complexes

Uttam Kumar Saha、Katsuhiro Inoue、S. Hiradate1998-07-01Soil Science Society of America Journal

Abstract Hydroxyaluminosilicate (HAS) ions were prepared from solutions containing hydroxyaluminum (HyA) ions and orthosilicic acids at an Al concentration of ≈4 m M ; Si/Al molar ratios of 0, 0.25, 0.5, and 1.0; and NaOH/Al molar ratios of 1.0, 2.0, and 2.5. Phosphate retention behavior of montmorillonite (Mt) carryi…

Clay minerals and soil interactionsIron oxide chemistry and applicationsPhosphorus and nutrient management

Focused-ion-beam-assisted etching of diamond in XeF2

Jun Taniguchi、Naoto Ohno、Shuuichi Takeda 等 5 位作者1998-07-01Journal of Vacuum Science & Technology B Microelectronics and Nanometer Structures Processing Measurement and Phenomena

Ga focused-ion-beam (FIB)-assisted etching of single-crystal diamond and thin film diamond in XeF2 was studied. The etch yield in FIB-assisted etching of diamond in XeF2 is enhanced some six times over the physical sputtering yield. In the crystal orientation dependence of the etch yield in FIB-assisted etching, the (…

Diamond and Carbon-based Materials ResearchIon-surface interactions and analysisIntegrated Circuits and Semiconductor Failure Analysis

Beyond Space Groups: the Arithmetic Symmetry of Deformable Multilattices

Mario Pitteri、Giovanni Zanzotto1998-07-01Acta Crystallographica Section A Foundations of Crystallography

It is well known that the problem of classifying the symmetry of simple lattices leads to consideration of the conjugacy properties of the holohedral crystallographic point groups (`holohedries'). Classical results for the three-dimensional case then state that: (i) the orthogonal classification of the holohedries sub…

Crystal Structures and PropertiesSolid-state spectroscopy and crystallographyQuasicrystal Structures and Properties

Supramolecular Assemblies Comprised of One-Dimensional Mixed Valence Platinum Complex and Anionic Amphiphiles in Organic Media

Nobuo Kimizuka、Noriko Oda、Toyoki Kunitake1998-07-01Chemistry Letters

Abstract A novel class of one-dimensional supramolecular assembly dispersed in organic media was prepared from halogen-bridged mixed valence platinum complex and anionic amphiphiles. Their intervalence absorption characteristics and nanostructures varied depending on the chemical structure of amphiphiles.

Supramolecular Chemistry and ComplexesPorphyrin and Phthalocyanine ChemistryLuminescence and Fluorescent Materials

Fine Control of Pore Size of Highly Ordered MCM-41 by Using Template Mixtures of Dodecyltrimethylammonium Bromide/Hexadecyltrimethylammonium Bromide with Various Molar Ratios

Seitarô Namba、Atsushi MOCHIZUKI、M. Kito1998-07-01Chemistry Letters

Abstract MCM-41 materials were prepared hydrothermally by using template mixtures of hexadecyltrimethylammonium/dodecyltrimethylammonium (C16TMABr/C12TMABr) with various molar ratios. The MCM-41 materials thus prepared were highly ordered and their pore sizes can be finely controlled by changing the C16TMABr/C12TMABr…

Metal-Organic Frameworks: Synthesis and ApplicationsZeolite Catalysis and SynthesisMesoporous Materials and Catalysis

Temperature-Composition Phase Diagram of the Organic Alloys, λ-BETS2(FeXGa1−X)Cl4, with Mixed Magnetic and Non-Magnetic Anions

Akane Sato、E. Ojima、Hiroki Akutsu 等 6 位作者1998-07-01Chemistry Letters

Abstract The electrical properties of a series of λ-type BETS conductors, λ-BETS2(FexGa1−x)Cl4 can be controlled continuously by varying the x-value. The system shows a metal-insulator transition for x &amp;gt; x1 (x1 ≈ 0.5) and a superconducting transition for x &amp;lt; x1. The T-x phase diagram indicates that the s…

Perovskite Materials and ApplicationsMagnetism in coordination complexesOrganic and Molecular Conductors Research

New Lanthanide Selenophosphates. Influence of Flux Composition on the Distribution of [PSe4]3-/[P2Se6]4- Units and the Stabilization of the Low-Dimensional Compounds A3REP2Se8, and A2(RE)P2Se7 (A = Rb, Cs; RE = Ce, Gd)

Konstantinos Chondroudis、Mercouri G. Kanatzidis1998-07-01Inorganic Chemistry

The reaction of Ce or Gd with a molten mixture of A(2)Se/P(2)Se(5)/Se (A = Rb, Cs) produced the quaternary compounds Rb(3)CeP(2)Se(8) (I) and Cs(3)GdP(2)Se(8) (II), as well as Rb(2)CeP(2)Se(7) (III) and Rb(2)GdP(2)Se(7) (IV). The orange crystals of I, II and the red crystals of III, IV are air- and water-sensitive. Co…

Crystal Structures and PropertiesOrganometallic Compounds Synthesis and CharacterizationInorganic Chemistry and Materials

Synthesen, spektroskopische Eigenschaften und Kristallstrukturen zweikerniger homo- und heteroleptischer μ-Carbido-Komplexe von Eisen(IV) mit Phthalocyaninat- und Tetraphenylporphyrinat-Liganden

Lutz Galich、Arne Kienast、H. Hückstädt 等 4 位作者1998-07-01Zeitschrift für anorganische und allgemeine Chemie

μ-Carbidophthalocyaninato(2–)eisen(IV)tetraphenylporphyrinato(2–)eisen(IV) (2) wird neben μ-Carbido-bis(tetraphenylporphyrinato(2–)eisen(IV)) (1) durch die Reaktion von Phthalocyaninato(2–)ferrat(I) mit Dichlorcarbentetraphenylporphyrinato(2–)eisen(II) dargestellt. 1 und 2 lösen sich wie μ-Carbido-bis(phthalocyaninato…

Magnetism in coordination complexesPorphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation Mechanisms

Generation of Chirality in Guest Aromatic Ketones Included in the Crystals of Steroidal Bile Acids

М. Gdaniec、T. Połoński1998-07-01Journal of the American Chemical Society

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTGeneration of Chirality in Guest Aromatic Ketones Included in the Crystals of Steroidal Bile AcidsMaria Gdaniec and Tadeusz PołońskiView Author Information Faculty of Chemistry, A. Mickiewicz University 60-780 Poznań, Poland Department of Chemistry, Technical Universit…

Crystallography and molecular interactionsAnalytical Chemistry and ChromatographyCrystallization and Solubility Studies

Measurement of foam modulus via a vane rheometer

X. D. Zhang、David W. Giles、Victor H. Barocas 等 5 位作者1998-07-01Journal of Rheology

A vane rheometer was used to measure the modulus of foam systems. Modulus development in a reactive polyurethane foam system was captured using a commercial stress-controlled rheometer with a four-blade vane geometry test fixture. The results were compared to those from a temperature programmed flooded parallel plate…

Enhanced Oil Recovery TechniquesPetroleum Processing and AnalysisPickering emulsions and particle stabilization

Dynamics of Polymer Interdiffusion: The Ripple Experiment

K. A. Welp、Richard P. Wool、Sushil K. Satija 等 5 位作者1998-07-01Macromolecules

We explore the interdiffusion of oppositely labeled triblock polystyrene chains, HDH/DHD, during welding in the melt using dynamic secondary ion mass spectroscopy (DSIMS) and specular neutron reflectivity (SNR). The HDH chains have the central portion of the chain deuterated (D) approximately 50% while the two ends (H…

Polymer crystallization and propertiesMaterial Dynamics and PropertiesForce Microscopy Techniques and Applications

On the Prediction of Crystal Morphology. II. Symmetry Roughening of Pairs of Connected Nets

Hugo Meekes、P. Bennema、R. F. P. Grimbergen1998-07-01Acta Crystallographica Section A Foundations of Crystallography

Within the framework of the periodic bond chain analysis for the prediction of crystal morphology, connected nets play a crucial role. For a face (hkl) often more than one connected net is found. Symmetry relations between such connected nets can give rise to symmetry roughening of nets. In this paper, all cases where…

Crystallography and molecular interactionsCrystallization and Solubility StudiesX-ray Diffraction in Crystallography

Increased efficiency of silicon light-emitting diodes in a standard 1.2-μm silicon complementary metal oxide semiconductor technology

Lukas W. Snyman1998-07-01Optical Engineering

Scaled versions of a variety of silicon light-emitting diode elements (Si LEDs) have been realized using a standard 1.2-µm, doublepolysilicon, double-metal, n-well CMOS fabrication process. The devices operated with a n+p junction biased in the avalanche breakdown mode and were realized by using standard features of t…

GaN-based semiconductor devices and materialsThin-Film Transistor TechnologiesSilicon Nanostructures and Photoluminescence

Enhanced surface metallic density of states in icosahedral quasicrystals

G. Neuhold、S. R. Barman、K. Horn 等 6 位作者1998-07-01Physical review. B, Condensed matter

Valence and core-level photoemission spectra show that cleaved $i$-Al-Pd-Mn quasicrystals have a pronounced metallic signature. Spectra from states above ${E}_{F},$ populated by increasing the sample temperature, indicate the presence of a shallow pseudogap 0.09 eV above ${E}_{F}.$ The Al $2p$ line asymmetry, on the o…

Advanced Chemical Physics StudiesQuasicrystal Structures and PropertiesX-ray Diffraction in Crystallography

X-PEEM Study on Surface Orientation of Stylized and Rubbed Polyimides

A. Cossy-Favre、J. Dı́az、Yong Liu 等 9 位作者1998-07-01Macromolecules

X-ray photoelectron emission microscopy (X-PEEM) was used to study the surface orientation of stylized and rubbed polyimide thin films. Using soft X-rays produced by a synchrotron light source, this technique combines high spatial resolution imaging with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy…

Liquid Crystal Research AdvancementsPolymer Nanocomposites and PropertiesSynthesis and properties of polymers

Hybrid Xerogels from Dendrimers and Arborols

Bruno Boury、Robert J. P. Corriu、Rosario Núñez1998-07-01Chemistry of Materials

Dendrimers and arborols with a carbosilane core have been prepared by a divergent hydrosilylation/vinylation reaction sequence followed by methoxylation of the silicon chloride end groups. Dendrimers with respectively 12 [first generation (1G)] and 36 [second generation (2G)] methoxysilane groups and arborols with oct…

Dendrimers and Hyperbranched PolymersCovalent Organic Framework ApplicationsSynthesis and properties of polymers

A comparative Raman study of ferroelectric PbTiO3 single crystal and thin film prepared on MgO substrate

Yu. I. Yuzyuk、R. Farhi、Vladimir Lorman 等 7 位作者1998-07-01Journal of Applied Physics

A Raman study of a highly oriented PbTiO3 thin film deposited on a MgO single crystal has been performed as a function of the temperature. The results have been compared with those obtained from a single crystal prepared from the same batch and those reported in the literature for polycrystalline thin films and single…

Ferroelectric and Piezoelectric MaterialsPhotorefractive and Nonlinear OpticsAcoustic Wave Resonator Technologies