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Polymerisation, basicity, oxidation state and their role in ionic modelling of silicate melts

Roberto Moretti2005-12-25Annals of Geophysics

In order to describe and quantify the reactivity of silicate melts, the ionic notation provided by the Temkin formalism has been historically accepted, giving rise to the study of melt chemical equilibria in terms of completely dissociated ionic species. Indeed, ionic modelling of melts works properly as long as the t…

Glass properties and applicationsMetallurgical Processes and ThermodynamicsPigment Synthesis and Properties

Microstructural studies on lattice imperfections in irradiated Titanium and Ti-5%Ta-2%Nb by X-Ray Diffraction Line Profile Analysis

P. Mukherjee、A. SARKAR、P. BARAT 等 5 位作者2005-12-25arXiv

The microstructural parameters like the average domain size, effective domain size at a particular crystallographic direction and microstrain within the domains of titanium and Ti-5%Ta-2%Nb, irradiated with 116 MeV O5+ ion, have been characterized as a function of dose by X-Ray Diffraction Line Profile Analysis using…

Materials Science

Lead zinc borate, PbZn2(BO3)2

Xue-An Chen、Yangchun Zhao、Xin-An Chang 等 5 位作者2005-12-24Acta Crystallographica Section C Crystal Structure Communications

PbZn2(BO3)2 crystallizes in the space group Pccn, with the Pb cation at a site with imposed twofold symmetry. The compound represents a new structure type in which ZnBO3 layers are bridged by Pb2+ cations, giving rise to a three-dimensional framework. Channels parallel to the [010] direction accommodate the stereochem…

Crystal Structures and PropertiesSolid-state spectroscopy and crystallographyX-ray Diffraction in Crystallography

Structural and Magnetic Properties of Topotactically Reduced YSr2Mn2O7-x (0 < x < 1.5)

Michael A. Hayward2005-12-24Chemistry of Materials

Reaction of the n = 2 Ruddlesden−Popper phase YSr 2 Mn 2 O 7 with NaH at 225 °C yields the topotactically reduced phase YSr 2 Mn 2 O 5.43(3) ( a = 3.62043(4) Å, c = 22.3570(3) Å). Combination of this reduced phase with the stoichiometric starting material at 400 °C yields intermediate phases: YSr 2 Mn 2 O 6.54(3) ( a…

Magnetic and transport properties of perovskites and related materialsMultiferroics and related materialsAdvanced Condensed Matter Physics

Sulfated Mesoporous Alumina: A Highly Effective Solid Strong Base Catalyst for the Tishchenko Reaction in Supercritical Carbon Dioxide

Tsunetake Seki、Makoto Onaka2005-12-24The Journal of Physical Chemistry B

Heterogeneous strong base catalysis for the intramolecular Tishchenko reaction of aromatic 1,2-dicarbaldehydes to the corresponding phthalides in supercritical CO2CscCO2 has been realized with mesoporous alumina containing SO4(2-) ions in the alumina framework (mesoAl2O3/SO4(2-)). Infrared spectroscopy of pyrrole adso…

Zeolite Catalysis and SynthesisMesoporous Materials and CatalysisCatalysis and Oxidation Reactions

Aggregation of [(tBu3SiS)MX]: Structures of {[Br2Fe(μ-SSitBu3)2FeBr(THF)]Na(THF)4}∞, cis-[(THF)FeI]2(μ-SSitBu3)2, [(tBu3SiS)Fe]2(μ-SSitBu3)2, and Comparative Structure and Magnetism Studies of [(tBu3SiS)MX]n (M = Fe, Co, X = Cl, n = 12; M = Fe, Ni, X = Br, n = 12; M = Fe, X = I, n = 14)

Orson L. Sydora、Thomas Henry、Peter T. Wolczanski 等 6 位作者2005-12-24Inorganic Chemistry

A convenient synthesis of (t)Bu(3)SiSH and (t)Bu(3)SiSNa(THF)(x)() led to the exploration of "(t)Bu(3)SiSMX" aggregation. The dimer, [((t)Bu(3)SiS)Fe](2)(mu-SSi(t)Bu(3))(2) (1(2)), was formed from [{(Me(3)Si)(2)N}Fe](2)(mu-N(SiMe(3))(2))(2) and the thiol, and its dissolution in THF generated ((t)Bu(3)SiS)(2)Fe(THF)(2)…

Organometallic Complex Synthesis and CatalysisMagnetism in coordination complexesInorganic Chemistry and Materials

A Comparative Mechanistic Study of the Reversible Binding of NO to a Water-Soluble Octa-Cationic FeIII Porphyrin Complex

Joo‐Eun Jee、Maria Wolak、Domenico Balbinot 等 6 位作者2005-12-24Inorganic Chemistry

The water-soluble, non-mu-oxo dimer-forming porphyrin, [5,10,15,20-tetrakis-4'-t-butylphenyl-2',6'-bis-(N-methylene-(4''-t-butylpyridinium))porphyrinato]iron(III) octabromide, (P(8+))Fe(III), with eight positively charged substituents in the ortho positions of the phenyl rings, was characterized by UV-vis and 1H NMR s…

Nitric Oxide and Endothelin EffectsPorphyrin and Phthalocyanine ChemistryHemoglobin structure and function

Syntheses, Structures, and Magnetic Properties of Cyano-Bridged Heterobimetallic Complexes Based on [Fe(bpca)(CN)3]-

He‐Rui Wen、Cai‐Feng Wang、Jing‐Lin Zuo 等 6 位作者2005-12-24Inorganic Chemistry

Two new cyano-bridged one-dimensional heterobimetallic coordination polymers, [(bpca)(2)Fe(III)(2)(CN)(6)Cu(H(2)O)(2).1.5H(2)O](n)() (2) and [(bpca)Fe(III)(CN)(3)Cu(bpca)(H(2)O).H(2)O](n)() (3), and a trinuclear complex, [(bpca)(2)Fe(III)(2)(CN)(6)Mn(CH(3)OH)(2)(H(2)O)(2)].2H(2)O (4), have been synthesized using the t…

Metal-Organic Frameworks: Synthesis and ApplicationsMagnetism in coordination complexesLanthanide and Transition Metal Complexes

Orbital Angular Momentum Contribution to the Magneto-Optical Behavior of a Binuclear Cobalt(II) Complex

S. Ostrovsky、K. Falk、J. Pelikan 等 6 位作者2005-12-24Inorganic Chemistry

We report magnetic and magnetic circular dichroism investigations of a binuclear Co(II) compound. The Hamiltonian of the system involves an isotropic exchange interaction dealing with the real spins of cobalt(II) ions, spin-orbit coupling, and a low-symmetry crystal field acting within the (4)T(1g) ground manifold of…

Magnetism in coordination complexesPorphyrin and Phthalocyanine ChemistryMolecular spectroscopy and chirality

Nanonecklaces of Platinum and Gold with High Aspect Ratios Synthesized in Mesoporous Organosilica Templates by Wet Hydrogen Reduction

Atsushi Fukuoka、Takanori Higuchi、Toshiyuki Ohtake 等 9 位作者2005-12-24Chemistry of Materials

Nanowires of platinum and gold with high aspect ratios are synthesized in one-dimensional channels of ordered mesoporous organosilica HMM. Water-saturated hydrogen reduction (wet H 2 -reduction) is significantly effective for large-scale synthesis of long nanowires, while dry H 2 -reduction gives monodispersed metal n…

Electrocatalysts for Energy ConversionMesoporous Materials and CatalysisNanoporous metals and alloys

The Crystal Structure of (S)-3-O-Geranylgeranylglyceryl Phosphate Synthase Reveals an Ancient Fold for an Ancient Enzyme

Jian Payandeh、M. Fujihashi、W. Gillon 等 4 位作者2005-12-24Journal of Biological Chemistry

We report crystal structures of the citrate and sn-glycerol-1-phosphate (G1P) complexes of (S)-3-O-geranylgeranylglyceryl phosphate synthase from Archaeoglobus fulgidus (AfGGGPS) at 1.55 and 2.0 A resolution, respectively. AfGGGPS is an enzyme that performs the committed step in archaeal lipid biosynthesis, and it pre…

Protein Structure and DynamicsEnzyme Structure and FunctionPlant biochemistry and biosynthesis

Analysis of the Secondary Structure of Random Copolymers by a Combination of Fluorescence and Molecular Dynamics Methods. Application to Polyphosphazenes Containing Phenoxy and Binaphthoxy Groups

Gema Marcelo、Enrique Sáiz、Francisco Mendicuti 等 6 位作者2005-12-24Macromolecules

Steady-state and time-resolved fluorescence techniques are combined with theoretical molecular dynamics calculations and applied to study the secondary structure of some random copolymers of polyphophazenes containing phenoxy and binaphthoxy chromophoric groups. Analysis of excitation and emission spectra, fluorescenc…

Photochemistry and Electron Transfer StudiesSynthesis and Properties of Aromatic CompoundsFlame retardant materials and properties

Rational Synthesis of meso- or β- Fluoroalkylporphyrin Derivatives via Halo-fluoroalkylporphyrin Precursors: Electronic and Steric Effects on Regioselective Electrophilic Substitution in 5-Fluoroalkyl-10,20-diarylporphyrins

Li‐Mei Jin、Liang Chen、Juanjuan Yin 等 6 位作者2005-12-24The Journal of Organic Chemistry

[reaction: see text] Electrophilic nitration, formylation or bromination of metalated 5-fluoroalkyl-10,20-diphenylporphyrin (fluoroalkyl = CF3, ClCF2CF2, n-C6F13) proceeded with high regioselectivity, exclusively affording corresponding meso-substituted porphyrins, while the iodination reaction mainly took place at th…

Porphyrin and Phthalocyanine ChemistryFluorine in Organic ChemistryPorphyrin Metabolism and Disorders

Temperature Dependence of the Raman Spectra of Individual Carbon Nanotubes

Zhenping Zhou、Xinyuan Dou、Lijie Ci 等 11 位作者2005-12-24The Journal of Physical Chemistry B

Resonant Raman scattering (RRS) spectra of individual carbon nanotubes on a SiO2 substrate have been investigated first in the temperature range of 100-600 K (Phys. Rev. B 2002, 66, 115411). It was revealed by the intensity abnormality of the radial breathing mode (RBM) that the carbon nanotubes have a temperature-dep…

Carbon Nanotubes in CompositesGraphene research and applicationsFullerene Chemistry and Applications

Improvement of Fe/MgO Catalysts by Calcination for the Growth of Single- and Double-Walled Carbon Nanotubes

Guoqing Ning、Fei Wei、Qian Wen 等 6 位作者2005-12-24The Journal of Physical Chemistry B

Calcination at 900-1000 degrees C for 8-12 h of an Fe/MgO catalyst prepared by impregnation was found to result in a uniform MgFe2O4/MgO solid solution that showed a successful settling of well-dispersed iron species into the MgO lattice. During methane reduction, many iron-containing particles with a diameter of abou…

Carbon Nanotubes in CompositesGraphene research and applicationsChemical and Physical Properties of Materials

Design, Synthesis, and Characterization of Bent-Core Mesogen-Jacketed Liquid Crystalline Polymers

Xiaofang Chen、Kishore Tenneti、Christopher Y. Li 等 8 位作者2005-12-24Macromolecules

We report the design, synthesis, and characterization of a series of mesogen-jacketed liquid crystalline polymers with bent-core liquid crystals (BCLCs). For the first time, BCLC mesogens were directly side-attached to the polymer backbone and bent-core mesogen-jacketed liquid crystalline polymers (BMJLCPs) were achie…

Liquid Crystal Research AdvancementsBlock Copolymer Self-AssemblyAdvanced Materials and Mechanics

Preparation and Characterization of a Carbon Nanotube−Lyotropic Liquid Crystal Composite

V. W. Weiss、Rajagopalan Thiruvengadathan、Oren Regev2005-12-24Langmuir

We present a detailed study on the integration of individual single-walled carbon nanotubes (SWNTs) within a lyotropic hexagonal liquid crystal (LC) for the first time. Two systems are studied in this work; in the first, the same surfactant is used for both the dispersion of the SWNTs and the formation of the LC. In t…

Carbon Nanotubes in CompositesLiquid Crystal Research AdvancementsMechanical and Optical Resonators

Azobenzene-Tethered T7 Promoter for Efficient Photoregulation of Transcription

Mingzhe Liu、Hiroyuki Asanuma、Makoto Komiyama2005-12-24Journal of the American Chemical Society

Azobenzene was additionally introduced into side chain of T7 promoter for the photocontrol of transcription reaction by T7 RNA polymerase (T7 RNAP). When a single azobenzene molecule was introduced into the T7 promoter either at the loop-binding region of the RNAP (-7 to -11 position) or at the unwinding region (-1 to…

Advanced biosensing and bioanalysis techniquesDNA and Nucleic Acid ChemistryPhotochromic and Fluorescence Chemistry

CO Adsorption on CoMo and NiMo Sulfide Catalysts: A Combined IR and DFT Study

Arnaud Travert、Christophe Dujardin、Françoise Maugé 等 7 位作者2005-12-24The Journal of Physical Chemistry B

Experimental IR spectra of carbon monoxide adsorbed on a series of Mo/Al2O3, CoMo/Al2O3, and NiMo/Al2O3 sulfided catalysts have been compared to ab initio DFT calculations of CO adsorption on CoMo and NiMo model surfaces. This approach allows the main IR features of CO adsorbed on the sulfide phase to be assigned with…

Catalytic Processes in Materials ScienceCatalysts for Methane ReformingCatalysis and Hydrodesulfurization Studies

Low density fragile states in cohesive powders

Paul B. Umbanhowar、Daniel I. Goldman2005-12-24arXiv

We discuss the difference between cohesive and non-cohesive granular media in the context of a recent report of "dry quicksand." Weak low density states with properties like dry quicksand are readily formed in common household powders. In contrast, such states cannot be formed in cohesionless granular media such as or…

Materials ScienceSoft Condensed Matter