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Confirmation of universality of time–humidity superposition principle for various water‐absorbable polymers through dynamic viscoelastic measurements under controlled conditions of relative humidity and temperature

S.‐M. Zhou、Kohji Tashiro、T. Ii2001-05-25Journal of Polymer Science Part B Polymer Physics

Abstract Dynamic viscoelastic measurements were made for storage ( E ′) and loss ( E ″) tensile moduli of water‐absorbable polymers such as nylon‐6, nylon‐66, poly(vinyl alcohol), ethylene–vinyl alcohol copolymers, and regenerated cellulose under the control of stepwise scanned relative humidity at constant temperatur…

Polymer crystallization and propertiesPolymer Nanocomposites and PropertiesHigh voltage insulation and dielectric phenomena

Tuning Intermolecular Interactions: A Study of the Structural and Vibrational Properties of p-Hexaphenyl under Pressure

S. Guha、W. Graupner、Roland Resel 等 7 位作者2001-05-25The Journal of Physical Chemistry A

Hydrostatic pressure is used to modulate the intermolecular interactions in the conjugated oligophenyl, para -hexaphenyl. These interactions affect the structural properties and also cause changes in the molecular geometry that directly alter the electronic properties. We use Raman spectroscopy to investigate the natu…

Nonlinear Optical Materials ResearchPhotochemistry and Electron Transfer StudiesSpectroscopy and Quantum Chemical Studies

Surface Modification of Polycarbonate and Poly(ethylene terephthalate) Films and Membranes by Polyelectrolyte Deposition

L. Dauginet、Anne‐Sophie Duwez、R. Legras 等 4 位作者2001-05-25Langmuir

The surface modification by chemical or physical adsorption of a polyelectrolyte (polyallylamine, PAH) was established using hydrolyzed polycarbonate (PC) and poly(ethylene terephthalate) (PET) thick and thin films. Contact angle data indicated changes in the hydrophilicity of PET film surfaces in terms of the chemica…

Advanced Sensor and Energy Harvesting MaterialsConducting polymers and applicationsPolymer Surface Interaction Studies

Precious Metal−Molecular Oxygen Complexes: Neon Matrix Infrared Spectra and Density Functional Calculations for M(O2), M(O2)2 (M = Pd, Pt, Ag, Au)

Xuefeng Wang、Lester Andrews2001-05-25The Journal of Physical Chemistry A

Laser-ablated palladium, platinum, silver, and gold atoms react with molecular oxygen in excess neon during condensation at 4 K. Reaction products, M-(η 2 -OO), M-(η 2 -OO) 2 (M = Pd, Pt), PtO, PtO 2, AuO 2, M-(η 1 -OO) (M = Ag, Au), and anions Ag-(η 1 -OO) -, Au-(η 1 -OO) 2 -, are identified from isotopic shifts and…

Advanced Chemical Physics StudiesCatalytic Processes in Materials ScienceMass Spectrometry Techniques and Applications

Origin of the Elastic Behavior of Syndiotactic Polypropylene

Finizia Auriemma、Odda Ruiz de Ballesteros、Claudio De Rosa2001-05-25Macromolecules

An analysis of the mechanical properties and a detailed structural study of samples of syndiotactic polypropylene (sPP) are presented in order to clarify the origin of the elastic behavior of sPP. Samples of sPP having different stereoregularity and showing different polymorphic behavior have been analyzed. The presen…

Polymer crystallization and propertiesPolymer Nanocomposites and PropertiesFiber-reinforced polymer composites

Melting and Crystallization of Polyethylene of Different Molar Mass by Calorimetry

Jeongihm Pak、Bernhard Wunderlich2001-05-25Macromolecules

Crystallization and melting of n -paraffins of chain lengths up to C 60 H 122 can be largely reversible, and practically no supercooling is seen in differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC). To find the changes with chain length for this effect, polyethylene fractions of oligomers o…

Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties

Crystallisation of the Stable Polymorph of Hydroxytriendione: Seeding Process and Effects of Purity

Wolfgang Beckmann、Wolfgang Otto、U. Budde2001-05-25Organic Process Research & Development

The drug substance hydroxytriendione has been found to exist in three modifications, which are equal in their pharmaceutical profile and are equally stable. Thus, Form II, the polymorph thermodynamically stable at room temperature, was chosen as the solid-state form for the active pharmaceutical ingredient. Spontaneou…

Drug Solubulity and Delivery SystemsAnalytical Chemistry and ChromatographyCrystallization and Solubility Studies

Influence of hydrogen bonding on the second harmonic generation effect: neutron diffraction study of 4-nitro-4′-methylbenzylidene aniline

Jacqueline M. Cole、J.A.K. Howard、Garry J. McIntyre2001-05-25Acta Crystallographica Section B Structural Science

A neutron diffraction study of the non-linear optical (NLO) material 4-nitro-4'-methylbenzylidene aniline (NMBA) is presented. NMBA exhibits a large macroscopic second-order NLO susceptibility, chi((2)), and this study shows that hydrogen bonding is, in part, responsible for this. No hydrogen bonding was reported in t…

Crystal structures of chemical compoundsCrystallography and molecular interactionsNonlinear Optical Materials Research

Theoretical calculations and predictions of the nonlinear optical coefficients of borate crystals

Zheshuai Lin、Jiao Lin、Z Z Wang 等 7 位作者2001-05-25Journal of Physics Condensed Matter

Theoretical methods to calculate the optical response of crystals are reviewed. The second-harmonic generation coefficients of borate nonlinear optical crystals are calculated using the anionic group theory combined with the Gaussian'92 ab initio calculation method. Without adjusting the parameters, the calculated val…

Crystal Structures and PropertiesSolid-state spectroscopy and crystallographyMineralogy and Gemology Studies

Electronic structure of the mixed valence system(YM)2BaNiO5 (M=Ca,Sr)

P. Novák、Florent Boucher、P. Gressier 等 5 位作者2001-05-25Physical review. B, Condensed matter

Electronic structure of the system ${\mathrm{Y}}_{2\ensuremath{-}x}{M}_{x}{\mathrm{BaNiO}}_{5} (M=\mathrm{C}\mathrm{a},\mathrm{S}\mathrm{r})$ was calculated for $x=0,$ 0.2, and 0.5 using the full-potential linearized augmented-plane-wave method. To describe the exchange and correlation the local spin-density approxima…

Physics of Superconductivity and MagnetismMagnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter Physics

Effect of off-stoichiometry on the transport properties of the Heusler-typeFe2VAlcompound

Yoichi Nishino、Hiroo Kato、Masaaki Kato 等 4 位作者2001-05-25Physical review. B, Condensed matter

We report on the effect of off-stoichiometry on the temperature dependence of electrical resistivity, the Seebeck coefficient, and the Hall coefficient in the Heusler-type ${\mathrm{Fe}}_{2}\mathrm{VAl}$ compound. While the stoichiometric ${\mathrm{Fe}}_{2}\mathrm{VAl}$ exhibits a semiconductorlike resistivity behavio…

Semiconductor materials and interfacesMXene and MAX Phase MaterialsHeusler alloys: electronic and magnetic properties

Rubbing-Induced Molecular Reorientation on an Alignment Surface of an Aromatic Polyimide Containing Cyanobiphenyl Side Chains

Jason J. Ge、Christopher Y. Li、Gi Xue 等 11 位作者2001-05-25Journal of the American Chemical Society

Surface lamellar decoration (SLD), surface enhanced Raman scattering (SERS) and optical second harmonic generation (SHG) experiments have been utilized to study the molecular orientation and conformation changes at a rubbed polyimide alignment-layer surface. This aromatic polyimide containing pendent cyanobiphenyl mes…

Organic Electronics and PhotovoltaicsLiquid Crystal Research AdvancementsSynthesis and properties of polymers

Fermi Surface Nesting and Nanoscale Fluctuating Charge/Orbital Ordering in Colossal Magnetoresistive Oxides

Yi‐De Chuang、A. D. Gromko、D. S. Dessau 等 5 位作者2001-05-25Science

We used high-resolution angle-resolved photoemission spectroscopy to reveal the Fermi surface and key transport parameters of the metallic state of the layered colossal magnetoresistive oxide La1.2Sr1.8Mn2O7. With these parameters, the calculated in-plane conductivity is nearly one order of magnitude larger than the m…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsElectronic and Structural Properties of Oxides

Surface States and Resonances in Field Emission from Low Index Facets of Clean Tungsten

Z. A. Ibrahim、M. J. G. Lee2001-05-25arXiv

The energies, widths, and shapes of features observed in the total energy distributions in field emission from W(100) and W(111) are compared with the results of a full-potential LAPW calculation of the surface density of states based on a supercell model of the crystal structure at the metal-vacuum interface. The Swa…

Materials Science

Two-Carrier Transport in Epitaxially Grown MnAs

J. J. Berry、S. J. Potashnik、S. H. Chun 等 6 位作者2001-05-25arXiv

Magneto-transport measurements of ferromagnetic MnAs epilayers grown by molecular beam epitaxy reveal the presence of both positive and negative charge carriers. Electrical transport at high temperatures is dominated by holes, and at low temperatures by electrons. We also observe distinct changes in the magnetoresista…

Materials Science

Nanosphere−Microsphere Assembly: Methods for Core−Shell Materials Preparation

Michael S. Fleming、Tarun K. Mandal、David R. Walt2001-05-25Chemistry of Materials

Core−shell composite materials consisting of a silica core and a polystyrene (PS) shell were prepared by colloidal assembly of PS nanospheres onto silica microspheres. The assembly process was controlled by specific chemical (amine−aldehyde) or biochemical (avidin−biotin) interactions between the nanospheres and micro…

Mesoporous Materials and CatalysisPolymer Surface Interaction StudiesPickering emulsions and particle stabilization

Nanoporous Thin Films Formed by Salt-Induced Structural Changes in Multilayers of Poly(acrylic acid) and Poly(allylamine)

Andreas Fery、Björn Schöler、Thierry Cassagneau 等 4 位作者2001-05-25Langmuir

We report here on the influence of changes in the solution salt concentration on the structure of multilayers of weak polyelectrolytes. For poly(acrylic acid) (PAA) and poly(allylamine) (PAH) multilayers assembled by the layer-by-layer process in the presence of sodium chloride, washing with pure water after depositio…

Polymer Surface Interaction StudiesMolecular Junctions and NanostructuresDendrimers and Hyperbranched Polymers

Relationship between bond valence and bond softness of alkali halides and chalcogenides

Stefan Adams2001-05-25Acta Crystallographica Section B Structural Science

Established bond-valence parameter tables rely on the assumption that the bond-valence sum of a central atom is fully determined by interactions to atoms in its first coordination shell. In this work the influence of higher coordination shells is tested in detail for bonds between lithium and oxygen. It is demonstrate…

Corrosion Behavior and InhibitionInorganic Chemistry and MaterialsThermal Expansion and Ionic Conductivity

Silk fibroin: Structural implications of a remarkable amino acid sequence

Cong‐Zhao Zhou、Fabrice Confalonieri、Michel Jacquet 等 6 位作者2001-05-25OpenAlex

The amino acid sequence of the heavy chain of Bombyx mori silk fibroin was derived from the gene sequence. The 5,263-residue (391-kDa) polypeptide chain comprises 12 low-complexity "crystalline" domains made up of Gly-X repeats and covering 94% of the sequence; X is Ala in 65%, Ser in 23%, and Tyr in 9% of the repeats…

Antimicrobial Peptides and ActivitiesSilk-based biomaterials and applicationsBiochemical and Structural Characterization

Copolymerization between A3 and B2 with Ring Formation and Different Intrinsic Reactivity in One of the Monomers

Selva Pereda、Adriana Brandolin、Enrique M. Vallés 等 4 位作者2001-05-24Macromolecules

We present two models for the stepwise copolymerization between a three-functional monomer A 3 and a bifunctional monomer B 2 where both intramolecular reaction and different intrinsic reactivities of reactive sites are present. The difference in reactivities may be either on the A sites or the B sites, leading to two…

Advanced Polymer Synthesis and CharacterizationPolymer Surface Interaction StudiesMolecular Junctions and Nanostructures