Materials Literature
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The molecular dynamics of semicrystalline poly(ether ether ketone) (PEEK) was studied over a broad dynamic range from 10 -1 to 10 9 Hz by combining dielectric spectroscopy (DS) and incoherent quasielastic neutron scattering (IQNS). This allowed us to characterize the polymer dynamics in the glassy, semicrystalline, an…
The pore structure of zeolite Y consists of 13 Å supercages connected through 7 Å windows. This study deals with the intrazeolitic photoelectron transfer from trisbipyridyl ruthenium (II) (Ru(bpy) 3 2+ ) synthesized within zeolite Y supercages to ion-exchanged bipyridinium molecules in neighboring supercages. Three N,…
Oriented polymer/silica composites have been synthesized by incorporating the conjugated semiconducting polymer MEH-PPV into the pores of an aligned, hexagonally ordered mesoporous silica. The ordered silica framework is synthesized by a silica/surfactant coorganization process that proceeds via a silicate/surfactant…
The photochemistry of CH 3 OH (a) and CH 3 O (a) adsorbed on TiO 2 and the effect of O 2 have been studied by infrared spectroscopy and mass spectrometry. In the absence of O 2, CH 3 OH (a) desorbs molecularly, while CH 3 O (a) decomposes to form CH 2 O (g) under UV irradiation. The rate of CH 3 O (a) decomposition re…
Phthalocyaninatosilicon(IV) covalently linked to a 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radical, SiPc-TEMPO, has been studied by time-resolved electron paramagnetic resonance (TREPR). A TREPR spectrum at 20 K is assigned to the doublet ground (D 0 ) state and the excited quartet (Q 1 ) state consisting of the…
Interactions of nitroxide-labeled polyamidoamine dendrimers of generations 2 and 6 (2SBD-T and 6SBD-T, respectively) with double-stranded polynucleotides Calf Thymus DNA (C.T.DNA), poly(deoxyadenylic−deoxythymidylic acid) (termed Poly(AT)), poly(deoxyguanylic−deoxycytidylic acid) (termed Poly(GC)), and a double-strand…
A series of novel aromatic polyimides that contain bis(2,2‘:6‘,2‘ ‘-terpyridine) ruthenium(II) complex was synthesized, and their optoelectronic properties were studied. The absorption of the polymers at 500 nm was strongly enhanced by the ruthenium complex. As a result, the photosensitivity of the polymers in the vis…
Thermogravimetric analysis (TGA), X-ray diffraction (XRD), BET areas, FT-IR spectroscopy, scanning electron microcopy (SEM) and temperature programmed reduction (TPR) techniques were performed to characterize copper−aluminum mixed-oxide samples with Cu/Al ratios between 0.5 and 3.0. The thermal stability, crystallinit…
The thermal decomposition pathways leading to the formation of volatile compounds and to char residue in poly(bisphenol A carbonate) ( PC ), poly(resorcinol carbonate) ( PRC ), and poly(hydroquinone carbonate) ( PHC ) have been investigated by mass spectrometry. The structure of the volatile compounds obtained in the…
We have recently developed some simple continuum models of static granular media which display "fragile" behaviour: they predict that the medium is unable to support certain types of infinitesimal load (which we call "incompatible" loads) without plastic rearrangement. We argue that a fragile description may be approp…
The solvothermal reaction of sulfur, selenium, or tellurium with cadmium metal powder in different organic solvents in the temperature range 120−200 °C was investigated systematically to prepare cadmium chalcogenides, CdE (E = S, Se, Te). The results showed that the character of the products, such as crystal size, sha…
The effects of the concentration of triphenylphosphine as a catalyst on the cure reaction of the biphenyl epoxy/phenol novolac resin system were studied. The kinetic study was carried out by means of the analysis of isothermal experiments using a differential scanning calorimeter. All kinetic parameters including the…
Select mechanical, thermal, and rheological properties of star-blocks consisting of 5–21 polystyrene-b-polyisobutylene (PSt-b-PIB) arms radiating from cyclosiloxane cores are described. The tensile properties of products containing 23–41 wt % of PSt are substantially higher (9.6–23.8 MPa) than those of linear triblock…
Thermal transitions of a glassy, main chain, liquid crystalline, random copolyester, HIQ-40, have been characterized. HIQ-40 is made from 40 mol percent p-hydroxybenzoic acid (HBA) and 30 mol % each of p-hydroquinone (HQ) and isophthalic acid (IA). This polymer is soluble in organic solvents, permitting the preparatio…
Polarized Raman spectra in ZnGeP2 crystal have been measured. The symmetry of vibrations has been assigned for every mode but one. The angular dispersion of the extraordinary phonon has been measured, and the result is described by the Loudon–Poulet approximation. Hydrostatic pressure dependence of Raman shift has bee…
Using angle-resolved photoemission spectroscopy, we probe the electronic band structure of ${\mathrm{TaTe}}_{4}$ single crystal samples. Resistivity and optical measurements were also performed on the same samples. The experimental data indicate a combination of quasi-one-dimensional and three-dimensional electronic p…
The electromigration wind force in various Al alloys is calculated using a Green's-function method for the calculation of the electronic structure. The influence of the environment of the jumping atoms is studied in detail in the Al-Cu alloy. Alloys of Al with $3d$ and $4sp$ alloying elements are studied systematicall…
We have observed local effects of the charge-density wave (CDW) in in situ Na-intercalated $1T\ensuremath{-}{\mathrm{VSe}}_{2}$ using scanning tunneling microscopy and spectroscopy between 300 and 60 K. Na intercalates nonuniformly, and divides the sample into intercalated (I) and nonintercalated (NI) areas. Below the…
We report on the evaluation of ion-beam induced damage in α-quartz and its dynamic annealing behavior in the temperature range between 80 and 1050 K using Rutherford backscattering spectrometry in channeling geometry. The results illustrate that the critical temperature for inhibiting amorphization during irradiation…
Metallic behavior down to low temperature is shown by charge transfer salts of BDH-TTP (1), a structural isomer of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF). In the case of (BDH-TTP)2PF6 this behavior is attributed to the structure, which is made up of κ-type sheets of BDH-TTP donor molecules and sheets of PF6−…