Materials Literature
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We studied the influence of π-orbital coupling in a 1D stack of 4,4‘-biphenyldithiol (BDT) on the resulting electronic and electrical properties of the assembly. The conduction and the field-switching properties of the BDT assembly are compared as the intermolecular distances are reduced to below 4 Å. The system in th…
The adsorption of pyrazole onto silver colloids has been investigated by surface-enhanced Raman scattering (SERS) experiments for normal and deuterated ligand and by ab initio density functional theory (DFT) calculations performed for surface complex models. The best agreement between observed and calculated frequenci…
Dissolution of the (104) surface of magnesite (MgCO 3 ) was studied as a function of bulk solution pH over the range 2.0 < pH < 5.0 at 60 °C using atomic force microscopy (AFM) with well-defined hydrodynamics. The experimental data and corresponding solution of the convective-diffusion equation for the system revealed…
The steady state and time resolved phophysical properties of a novel self-assembling lyotropic discotic liquid crystal, 2,3,6,7,10,11-hexa-(1,4,7-trioxaoctyl)-triphenylene (TP6EO2M) are reported. The spectral changes that accompany the formation of linear aggregates in D2O provide no evidence of excited-state delocali…
Abstract Styrene–butadiene rubber (SBR) and nitrile rubber (NBR) were reinforced with silica by the sol–gel method of tetraethoxysilane (TEOS) in latex. The sol–gel reaction proceeded in the mixture of latex, TEOS, water, and a catalyst. The compound that involved silica was crosslinked with the curing agent at 150°C.…
Abstract The graft crosslinking polymerization of 4‐ tert ‐butylstyrene (tBS) and divinylbenzene (DVB) onto ethylene–propylene–diene (EPDM) was carried out in toluene by using benzoyl peroxide (BPO) as an initiator. The synthesized graft terpolymer, tBS‐EPDM‐DVB (PBED), was extracted with tetrahydrofuran (THF) into ge…
Density functional theory (DFT) calculations of the energetics, molecular structures, and spin density profiles of metalloporphyrin pi-cation radicals suggest that the common practice of describing these radicals in terms of a universal A(1u)/A(2u) dichotomy is often not justified, confirming a possibility first fores…
We have measured the steady drainage of foams of various surfactants, varying the size of the parietal plateau borders from 0.24 to 2.4 mm. We report an evolution of the power laws of drainage with the bubble size, which cannot be explained by the most recent developments of the drainage theory. We believe that one re…
Redox polyelectrolyte multilayers have been assembled with use of the layer-by-layer (LBL) deposition technique with cationic poly(allylamine) modified with Os(bpy)(2)ClPyCHO (PAH-Os) and anionic poly(styrene)sulfonate (PSS) or poly(vinyl)sulfonate (PVS). Different behavior has been observed in the formal redox potent…
The kind and degree of crystalline phase orientation for clathrate s-PS films, obtained by solution-casting procedures, and for semicrystalline films, obtained by suitable treatments on these cast films, are analyzed. Clathrate as well as nanoporous form films can present high degrees of uniplanar orientation, corresp…
TDDFT calculations confirm a controversial proposal by DiMagno and co-workers that ruffling distortions, by themselves, do not bring about sizable red shifts in the electronic absorption spectra of "simple" nontransition-metal porphyrins. We now report that the same also holds for saddling distortions. The situation i…
The photoinduced electron transfer in differently linked zinc porphyrin-fullerene dyads and their free-base porphyrin analogues was studied in polar and nonpolar solvents with femto- to nanosecond absorption and emission spectroscopies. A new intermediate state, different from the locally excited (LE) chromophores and…
The oxidation of (tmeda)Pt(II)(CH(3))(2) (1, tmeda = N,N,N',N'-tetramethylethylenediamine) to (tmeda)Pt(IV)(OH)(OCH(3))(CH(3))(2) (3) by dioxygen in methanol proceeds via a two-step mechanism. The initial reaction between (tmeda)Pt(CH(3))(2) and dioxygen yields a hydroperoxoplatinum(IV) intermediate, (tmeda)Pt(OOH)(OC…
We examine some new DNLS-like equations that arise when considering strongly-coupled electron-vibration systems, where the local oscillator potential is anharmonic. In particular, we focus on a single, rather general nonlinear vibrational impurity and determine its bound state(s) and its dynamical selftrapping propert…
The average time for the onset of macroscopic fractures is analytically and numerically investigated in the fiber-bundle model with quenched disorder and thermal noise under a constant load. We find an implicit exact expression for the failure time in the low-temperature limit that is accurately confirmed by direct si…
Polymer-stabilized tetragonal ZrO(2) nanopowders with average size of ca. 2.0 nm have been prepared by microwave heating in an aqueous solution containing Zr(NO(3))(4) x 5H(2)O, PVA, and NaOH. The photoluminescence of the synthesized ZrO(2) fine particles has been investigated.
An extension of the original Overhauser effect to a more general nonequilibrium state was proposed by G. Feher, and demonstrated by Clark and Feher some forty years ago. It is suggested here that it might be possible to produce excess electron spin polarization by allowing the role of the nuclei to be played by other…
We present atomic and defect structural studies of technologically important gold nanorods synthesized by a wet chemical process. Our surface atomic structural studies and electron nanodiffraction from single nanorods have provided the first direct evidence of the stabilization of the highly unstable (110) surface by…
We present here a first systematic study of substituent effects in metallocorroles, based on electronic absorption, resonance Raman (RR), and infrared (IR) spectroscopic studies and electrochemical measurements on 10 copper(III) meso-triarylcorroles, Cu(III)[beta-Y(8)TArC], where the beta-substituent Y = H or Br and t…
ABSTRACT With the development of waterflooding in an oil field, water breakthroughsare a common problem. Polymer solutions are widely applied to resolve thewater-channeling problem in a deep formation. In practice, polymers are used asagents in deep formation treatment either to block in-depth high permeabilityzones o…