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Reactions of Ammonia on Stoichiometric and Reduced TiO2(001) Single Crystal Surfaces

Jarod Wilson、Hicham Idriss2004-11-04Langmuir

The reaction of NH(3) on the surface of the 011-faceted structure of the TiO(2)(001) single crystal is studied and compared to that on the O-defected surface. Temperature-programmed desorption (TPD) conducted after NH(3) adsorption at 300 K shows only molecular desorption at 340 K. Modeling of TPD signals as a functio…

Advanced Photocatalysis TechniquesCatalytic Processes in Materials ScienceGas Sensing Nanomaterials and Sensors

Migration Processes of the 30° Partial Dislocation in Silicon

Norihisa Oyama、Takahisa Ohno2004-11-04Physical Review Letters

The migration processes of the 30 degrees partial dislocation in silicon have been investigated using first-principles total-energy calculations. We have presented for the first time a reliable determination of the formation and migration energies of kinks, which are consistent with experiments. The obtained results i…

Microstructure and mechanical propertiesForce Microscopy Techniques and ApplicationsIon-surface interactions and analysis

Selective Adsorption of Microcapsules on Patterned Polyelectrolyte Multilayers

Jie Feng、Ben Wang、Changyou Gao 等 4 位作者2004-11-04Advanced Materials

Selective adsorption of microcapsules was achieved by utilizing electrostatic interactions between the capsule surfaces and chemically and physically patterned substrates. Pressing a poly(dimethylsiloxane) stamp consisting of periodic strips and inked with a poly(diallyldimethylammonium chloride) solution onto polyele…

Polymer Surface Interaction StudiesDendrimers and Hyperbranched PolymersNanofabrication and Lithography Techniques

Synthesis and complex permeability of Ni/SiO2 nanocomposite

Nujiang Tang、Weishen Zhong、W Liu 等 6 位作者2004-11-04Nanotechnology

The magnetic properties of Ni/SiO 2 nanocomposite prepared by a simple sol–gel combined hydrogen reduction method are reported. The real part of the permeability for Ni/SiO 2 nanoparticles is almost independent of frequency up to at least 1 GHz, and the loss of is very small. Our method provides a promising route to f…

Magnetic properties of thin filmsZnO doping and propertiesElectromagnetic wave absorption materials

Effect of sample preparation on the glass‐transition of thin polystyrene films

Zahra Fakhraai、James S. Sharp、James A. Forrest2004-11-04Journal of Polymer Science Part B Polymer Physics

Abstract We have investigated the effect of sample preparation on the glass‐transition temperature ( T g ) of thin films of polystyrene (PS). By preparing and measuring the glass‐transition temperature T g of multilayered polymer films, we are able to assess the contribution of the spincoating process to the reduced T…

Polymer crystallization and propertiesMaterial Dynamics and PropertiesTheoretical and Computational Physics

Dielectric Response in Bisquaric Acid Crystal: Possible Generation of Protonic Soliton in a Quasi-One-Dimensional Hydrogen-Bonded System

Isao Takasu、Tadashi Sugawara、Tomoyuki Mochida2004-11-04The Journal of Physical Chemistry B

We investigated the proton dynamics of crystalline bisquaric acid (H 2 BSQ) in terms of the temperature and frequency dependence of its permittivity. It was found that the dielectric response of the H 2 BSQ crystal exhibited two-step changes. With raising temperature, the dielectric permittivity increased slightly at…

Acoustic Wave Resonator TechnologiesSpectroscopy and Quantum Chemical StudiesSolid-state spectroscopy and crystallography

Further Investigation on Potassium-Induced Conformation Transition of Nephila Spidroin Film with Two-Dimensional Infrared Correlation Spectroscopy

Xianneng Peng、Zhengzhong Shao、Xin Chen 等 6 位作者2004-11-04Biomacromolecules

We used two-dimensional (2D) correlation infrared spectroscopy to study further the potassium-induced conformation transition in Nephila spidroin films. It provided increased resolution and important new information on the sequence of events in the conformation transition process, showing that beta-sheet formed from t…

Neurobiology and Insect Physiology ResearchSilk-based biomaterials and applicationsBiochemical and Structural Characterization

Density functional theory investigation of native defects inSiO2: Self-doping and contribution to ionic conductivity

Guido Roma、Yves Limoge2004-11-04Physical Review B

We present here a theoretical study of the effect of self-doping and the contribution of native defects to the ionic conductivity of $\ensuremath{\alpha}$-quartz. A thorough first principles study of native defects in quartz, comprising silicon and oxygen defects in several charge states, is presented. On the basis of…

Glass properties and applicationsSilicon Nanostructures and PhotoluminescenceElectronic and Structural Properties of Oxides

Texture formation under phase ordering and phase separation in polymer-liquid crystal mixtures

Susanta Das、Alejandro D. Rey2004-11-04The Journal of Chemical Physics

Computational modeling of texture formation in coupled phase separation-phase ordering processes in polymer/liquid crystal mixtures is performed using a unified model based on the nematic tensor order parameter and gradient orientation elasticity. The computational methods are able to resolve defect nucleation, defect…

Liquid Crystal Research AdvancementsMaterial Dynamics and PropertiesBlock Copolymer Self-Assembly

Phosphoryl Choline Introduces Dual Activity in Biomimetic Ionomers

Fredrik Nederberg、Tim Bowden、Bo Nilsson 等 5 位作者2004-11-04Journal of the American Chemical Society

Dual activity of phosphoryl choline (PC) functional poly(trimethylene carbonate) (PTMC) was found which induces the zwitterionic biomimetic PC group to form physical cross-links with ionomers in the bulk, and at the same time enrich at the surface of cast films. The formation of zwitterionic domains from a bifunctiona…

biodegradable polymer synthesis and propertiesElectrospun Nanofibers in Biomedical ApplicationsPolymer Surface Interaction Studies

Molecular dynamics investigation of the mechanical properties of gallium nitride nanotubes under tension and fatigue

Yeau‐Ren Jeng、Ping-Chi Tsai、Te‐Hua Fang2004-11-04Nanotechnology

This study adopts a classical molecular dynamics (MD) simulation with the realistic Tersoff many-body potential model to investigate the mechanical properties of gallium nitride (GaN) nanotubes. The investigation focuses primarily on the mechanical properties of ( n ,0) and ( n , n ) GaN nanotubes since these particul…

Carbon Nanotubes in CompositesThermal properties of materialsBoron and Carbon Nanomaterials Research

Tamoxifen‐Loaded Polymeric Micelles: Preparation, Physico‐Chemical Characterization and In Vitro Evaluation Studies

Gennara Cavallaro、Laura Maniscalco、Mariano Licciardi 等 4 位作者2004-11-04Macromolecular Bioscience

Several samples of polymeric micelles, formed by amphiphilic derivatives of PHEA, obtained by grafting into polymeric backbone of PEGs and/or hexadecylamine groups (PHEA-PEG-C(16) and PHEA-C(16)) and containing different amount of Tamoxifen, were prepared. All Tamoxifen-loaded polymeric micelles showed to increase dru…

Nanoparticle-Based Drug DeliveryAdvanced Polymer Synthesis and CharacterizationDendrimers and Hyperbranched Polymers

Mechanism of the Transition between Lamellar and Gyroid Phases Formed by a Diblock Copolymer in Aqueous Solution

Ian W. Hamley、Valeria Castelletto、Oleksandr O. Mykhaylyk 等 8 位作者2004-11-04Langmuir

The mechanism of the transition from a lamellar phase to a gyroid phase in an aqueous solution of a diblock copolymer has been studied by time-resolved synchrotron small-angle X-ray scattering. The transition occurs via a metastable perforated lamellar structure. The perforations initially have liquidlike ordering bef…

Material Dynamics and PropertiesSurfactants and Colloidal SystemsBlock Copolymer Self-Assembly

A molecular dynamics simulation of the melting points and glass transition temperatures of myo- and neo-inositol

S.W. Watt、James A. Chisholm、William Jones 等 4 位作者2004-11-04The Journal of Chemical Physics

The heat of sublimation, density, melting point, and glass transition temperature are calculated for myo- and neo-inositol, using the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field and molecular dynamics techniques. Our results show that the calculated heats of su…

Material Dynamics and PropertiesTheoretical and Computational PhysicsAdvanced Mathematical Theories and Applications

The fabrication of La(OH)3 nanospheres by a controllable-hydrothermal method with citric acid as a protective agent

Bo Tang、Jiechao Ge、Linhai Zhuo2004-11-04Nanotechnology

La(OH)3 nanospheres have been synthesized with La(NO3)3 and KOH as the starting materials and citric acid as a protective agent through a facile controllable hydrothermal method. The obtained products were analysed with x-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (S…

Luminescence Properties of Advanced MaterialsRadioactive element chemistry and processingExtraction and Separation Processes

Reverse Saturable Absorption in the Near‐Infrared by Fused Porphyrin Dimers

K. J. McEwan、Paul A. Fleitz、Joy E. Rogers 等 9 位作者2004-11-04Advanced Materials

Bromine and iodine substituents increase the yield of triplet excited states in a triply linked fused porphyrin dimer (see Figure), resulting in efficient reverse saturable absorption in the near-infrared range at 600–970 nm on the nanosecond timescale.

Porphyrin and Phthalocyanine ChemistryLuminescence and Fluorescent MaterialsNonlinear Optical Materials Studies

An efficient method for calculating maxima of homogeneous functions of orthogonal matrices: Applications to localized occupied orbitals

Joseph E. Subotnik、Yihan Shao、WanZhen Liang 等 4 位作者2004-11-04The Journal of Chemical Physics

We present here three new algorithms (one purely iterative and two DIIS-like [Direct Inversion in the Iteractive Subspace]) to compute maxima of homogeneous functions of orthogonal matrices. These algorithms revolve around the mathematical lemma that, given an invertible matrix A, the function f(U)=Tr(AU) has exactly…

Lanthanide and Transition Metal ComplexesChemical Thermodynamics and Molecular StructureFree Radicals and Antioxidants

Ultrafast excited-state dynamics in photochromic N-salicylideneaniline studied by femtosecond time-resolved REMPI spectroscopy

Chie Okabe、Takakazu Nakabayashi、Yoshiya Inokuchi 等 5 位作者2004-11-04The Journal of Chemical Physics

Ultrafast processes in photoexcited N-salicylideneaniline have been investigated with femtosecond time-resolved resonance-enhanced multiphoton ionization spectroscopy. The ion signals via the S(1)(n,pi( *)) state of the enol form as well as the proton-transferred cis-keto form emerge within a few hundred femtoseconds…

Photochemistry and Electron Transfer StudiesPhotochromic and Fluorescence ChemistryPhotoreceptor and optogenetics research

Identifying Defects in Nanoscale Materials

Masa Ishigami、Hyoung Joon Choi、Shaul Aloni 等 6 位作者2004-11-04Physical Review Letters

We have developed a novel iterative experimental-theoretical technique which can identify the atomic structure of defects in many-atom nanoscale materials from scanning tunneling microscopy and spectroscopy data. A given model for a defect structure is iteratively improved until calculated microscopy and spectroscopy…

Carbon Nanotubes in CompositesGraphene research and applicationsForce Microscopy Techniques and Applications

Studies on the Homogeneous Acetylation of Cellulose in the Novel Solvent Dimethyl Sulfoxide/Tetrabutylammonium Fluoride Trihydrate

Beatriz Aparecida Pereira Ass、Elisabete Frollini、Thomas Heinze2004-11-04Macromolecular Bioscience

The novel solvent dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride trihydrate (TBAF . 3H(2)O) was studied for acetylation of linters cellulose. In order to control the degree of substitution (DS), acetylation of the macromolecule was carried out at different reaction time and temperature, molar ratio of reactants…

Advanced Cellulose Research StudiesCarbohydrate Chemistry and Synthesis