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Ion Transport and Vibrational Spectra of Branched Polymer and Dendrimer Electrolytes

Rensl E. A. Dillon、Duward F. Shriver2001-03-09Chemistry of Materials

Solid electrolytes were prepared by the introduction of Li[(CF 3 SO 2 ) 2 N] into amorphous branched polymers and dendritic macromolecular hosts. These materials exhibit high ionic conductivity, but high concentrations of salt increase the glass transition temperatures, with an attendant decrease in ionic conductivity.

Conducting polymers and applicationsFlame retardant materials and propertiesDendrimers and Hyperbranched Polymers

Tetracyanomanganate(II) and Its Salts of Divalent First-Row Transition Metal Ions

Jamie L. Manson、Wayne E. Buschmann、Joel S. Miller2001-03-09Inorganic Chemistry

The first known paramagnetic, tetrahedral cyanide complex, [Mn(II)(CN)(4)](2)(-), is formed by the photoinduced decomposition of [Mn(IV)(CN)(6)](2)(-) in nonaqueous solutions or by thermal decomposition in the solid state. In acetonitrile or dichloromethane, photoexcitation into the ligand-to-metal charge transfer ban…

Magnetism in coordination complexesLanthanide and Transition Metal ComplexesOrganic and Molecular Conductors Research

The Optical Spectra of NiP, NiPz, NiTBP, and NiPc: Electronic Effects ofMeso-tetraaza Substitution and Tetrabenzo Annulation

Angela Rosa、Giampaolo Ricciardi、Evert Jan Baerends 等 4 位作者2001-03-09The Journal of Physical Chemistry A

Time-dependent density functional calculations have been performed on the symmetry and spin-allowed E u excited states of the nickel tetrapyrrole series, NiP, NiPz, NiTBP, and NiPc. Optical spectra collected in noncoordinating solvents are presented for NiTBP, for the newly synthesized octaethyl nickel porphyrazine, N…

Porphyrin and Phthalocyanine ChemistryPhotochemistry and Electron Transfer StudiesMetal-Catalyzed Oxygenation Mechanisms

Reversible Side Chain Modification through Noncovalent Interactions. “Plug and Play” Polymers

Faysal Ilhan、Mark Gray、Vincent M. Rotello2001-03-09Macromolecules

Polystyrene-based systems with varying donor−acceptor−donor (D−A−D) hydrogen bonding side chains were synthesized. Recognition interactions between these polymers and guest flavin 5 were studied through 1 H NMR titration experiments. Using these systems, we have shown that the efficiency of recognition between the pol…

Molecular Sensors and Ion DetectionSupramolecular Chemistry and ComplexesLuminescence and Fluorescent Materials

Magnetic Phase Diagram of Ca2-xSrxRuO4 Governed by Structural Distortions

Zhong Fang、Kiyoyuki Terakura2001-03-09arXiv

We constructed, by the first-principles calculations, a magnetic phase diagram of Sr$_{2}$RuO$_4$ in the space spanned by structural distortions. Our phase diagram can qualitatively explain the experimental one for Ca$_{2-x}$Sr$_x$RuO$_4$. We found that the rotation and the tilting of RuO$_6$ octahedron are responsibl…

Materials ScienceSuperconductivity

Structure and superconductivity of Mg(B1-xCx)2 compounds

Shao-ying Zhang、Jian Zhang、Tong-Yun Zhao 等 6 位作者2001-03-09arXiv

In this paper, we reported the structural properties and superconductivity of Mg(B1-xCx)2 compounds. Powder x-ray diffraction results indicate that the samples crystallize in a hexagonal AlB2-type structure. Due to the chemical activity of Mg powders, a small amount of MgO impurity phase was detected by x-ray diffract…

Materials Science

Surface Magnetic Phase Diagram of Tetragonal Manganites

Zhong Fang、Kiyoyuki Terakura2001-03-09arXiv

To gain insights into the fundamental and characteristic features of the surface of doped manganites, we constructed a general magnetic phase diagram of La$_{1-x}$Sr$_{x}$MnO$_3$ (001) surfaces in the plane spanned by $x$ and the bulk tetragonal distortion $c/a$, from the first-principles calculations. We found that t…

Materials ScienceStrongly Correlated Electrons

Spiral cracks without twisting

K-t. Leung、L. Jozsa、M. Ravasz 等 4 位作者2001-03-09arXiv

A fascinating class of patterns, often encountered in nature as meandering cracks on rocks, dried-out fields and tectonic plates is produced by the fracture of solids. Here we report the observation and modeling of an unusual type of patterns consisting of spiral cracks within fragments of a thin layer of drying preci…

Materials ScienceSoft Condensed Matter

Conduction mechanism and magnetotransport in multi-walled carbon nanotubes

Stephan Roche、Francois Triozon、Angel Rubio 等 4 位作者2001-03-09arXiv

We report on a numerical study of quantum diffusion over micron lengths in defect-free multi-walled nanotubes. The intershell coupling allows the electron spreading over several shells, and when their periodicities along the nanotube axis are incommensurate, which is likely in real materials, the electronic propagatio…

Mesoscale and Nanoscale PhysicsMaterials Science

Synthesis of a Terbium Fluorescent Chelate and Its Application to Time-Resolved Fluoroimmunoassay

Jingli Yuan、Guilan Wang、Keisuke Majima 等 4 位作者2001-03-09Analytical Chemistry

A new nonadentate ligand, N, N, N1, N1-[2,6-bis(3'-aminomethyl-1'-pyrazolyl)-4-phenylpyridine]tetrakis(acetic acid) (BPTA) for a Tb3+ fluorescent complex was synthesized. The Tb3+ complex is strongly fluorescent, having a large fluorescence quantum yield of 1.00 and very long fluorescence lifetime of 2.681 ms in 0.05…

Medical Imaging Techniques and ApplicationsLanthanide and Transition Metal ComplexesRadiopharmaceutical Chemistry and Applications

Nanobelts of Semiconducting Oxides

Zhengwei Pan、Z. R. Dai、Zhong Lin Wang2001-03-09OpenAlex

Ultralong beltlike (or ribbonlike) nanostructures (so-called nanobelts) were successfully synthesized for semiconducting oxides of zinc, tin, indium, cadmium, and gallium by simply evaporating the desired commercial metal oxide powders at high temperatures. The as-synthesized oxide nanobelts are pure, structurally uni…

ZnO doping and propertiesNanowire Synthesis and ApplicationsGa2O3 and related materials

The effect of proton interactions on the conductivity behavior in systems with superionic phases

N.I. Pavlenko、I. V. Stasyuk2001-03-08The Journal of Chemical Physics

The proton conductivity in the hydrogen-bonded systems with strong correlations between protons is investigated theoretically in the context of the two-stage transport modeling approach. The distortions of the nearest ionic groups at the formation of the hydrogen bond are shown to be the reason for the strong proton–p…

Advancements in Solid Oxide Fuel CellsFuel Cells and Related MaterialsSolid-state spectroscopy and crystallography

Diblock Copolymer Ordering Induced by Patterned Surfaces above the Order−Disorder Transition

Yoav Tsori、David Andelman2001-03-08Macromolecules

We investigate the morphology of diblock copolymers in the vicinity of flat, chemically patterned surfaces. We use a Ginzburg−Landau free energy to describe the spatial variations of the order parameter in terms of a general two-dimensional surface pattern above the order−disorder transition. The propagation of severa…

Material Dynamics and PropertiesTheoretical and Computational PhysicsBlock Copolymer Self-Assembly

Cationic ring‐opening polymerization of six‐membered cyclic carbonates with ester groups

Nobukatsu Nemoto、Fumio Sanda、Takeshi Endo2001-03-08Journal of Polymer Science Part A Polymer Chemistry

Abstract This work deals with the cationic ring‐opening polymerization of the ester‐substituted cyclic carbonates 5‐methyl‐5‐benzoyloxymethyl‐1,3‐dioxan‐2‐one ( CC1 ) and 4‐benzoyloxymethyl‐1,3‐dioxan‐2‐one ( CC4 ). The polymerization was carried out with trifluoromethanesulfonic acid, methyl trifluoromethanesulfonate…

Advanced Polymer Synthesis and Characterizationbiodegradable polymer synthesis and propertiesCarbon dioxide utilization in catalysis

Raman and Fluorescence Spectra of Size-Selected, Matrix-Isolated C14 and C18 Neutral Carbon Clusters

Gregory A. Rechtsteiner、Christian Felix、Adina K. Ott 等 7 位作者2001-03-08The Journal of Physical Chemistry A

The surface plasmon polariton-enhanced Raman spectra of size-selected, matrix-isolated C 14 neutral clusters are presented along with the calculated vibrational frequencies for the ring and linear chain isomers. The Raman spectra show resonance enhancement over a range of excitation wavelengths from 457.9 to 514.5 nm.…

Advanced Chemical Physics StudiesPorphyrin and Phthalocyanine ChemistryPhotochemistry and Electron Transfer Studies

Human ornithine transcarbamylase: crystallographic insights into substrate recognition and conformational changes

Dashuang Shi、Hiroki Morizono、Xiaolin Yu 等 6 位作者2001-03-08Biochemical Journal

Two crystal structures of human ornithine transcarbamylase (OTCase) complexed with the substrate carbamoyl phosphate (CP) have been solved. One structure, whose crystals were prepared by substituting N-phosphonacetyl-L-ornithine (PALO) liganded crystals with CP, has been refined at 2.4 Å (1 Å = 0.1nm) resolution to a…

Metabolism and Genetic DisordersEnzyme Structure and FunctionAmino Acid Enzymes and Metabolism

Poly(lactide‐co‐glycolide) solution behavior in supercritical CO 2 , CHF 3 , and CHClF 2

S. E. Conway、H.‐S. BYUN、Mark A. McHugh 等 5 位作者2001-03-08Journal of Applied Polymer Science

Abstract Cloud point and solution density data between 20 and 100°C and pressures to 3000 bar are presented for poly(lactide) (PLA) and poly(lactide‐co‐glycolide) (PLGA x , where the molar concentration of glycolide in the backbone x ranges from 0 to 50 mol %) in supercritical CO 2 , CHClF 2 , and CHF 3 . PLA dissolve…

Phase Equilibria and ThermodynamicsCarbon dioxide utilization in catalysisPolymer Foaming and Composites

Synthesis of new polyureas derived from 4‐cyclohexylurazole

Shadpour Mallakpour、Hossein Rostamizadeh2001-03-08Journal of Applied Polymer Science

Abstract 4‐Cyclohexylurazole (1) R = cyclohexyl (CHU) was prepared from cyclohexyl isocyanate in two steps. Polycondensation reactions of compound CHU with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and toluene‐2,4‐diisocyanate (TDI) were performed in DMAc/chloroform and DMAC in the presence of…

Polymer composites and self-healingSynthetic Organic Chemistry MethodsSynthesis and properties of polymers

Surface modification of HDPE and PP by mechanical polishing and DC glow discharge and their adhesive joining to steel

Shantanu Bhowmik、P. K. Ghosh、S. Ray2001-03-08Journal of Applied Polymer Science

Abstract To improve the strengths of the adhesive joints of high density polyethylene (HDPE) and polypropylene (PP) to steel, the surfaces of HDPE and PP sheets have been treated by DC glow discharge to increase the polar component of surface energy significantly. Present study investigates the effect of mechanical po…

Surface Modification and SuperhydrophobicityAdvanced Sensor and Energy Harvesting MaterialsElectrostatic Discharge in Electronics

Statics and dynamics of a single polymer chain confined in a tube

Yu‐Jane Sheng、Meng-Chieh Wang2001-03-08The Journal of Chemical Physics

The static and nonequilibrium dynamic properties of a single linear chain confined in a cylindrical tube are studied by Monte Carlo simulations using a continuous model and by scaling calculations. Chain lengths from N=30 to 150 are considered. For the static results, our simulation data are consistent with the scalin…

Material Dynamics and PropertiesForce Microscopy Techniques and ApplicationsRheology and Fluid Dynamics Studies