Materials Literature
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Hybrid quantum mechanical/molecular mechanical potentials have proved to be powerful tools for the simulation of many processes in condensed phase systems and, as a result, there is much current research into how they can be improved. An area of recent attention has been the inclusion of polarization effects on the at…
In this article, initially, we designed a simple drilling apparatus to obtain the mechanoradicals of poly(methyl methacrylate) (PMMA). Using this apparatus, we prepared some PMMA samples at 77 K in vacuum. We observed some electron spin resonance (ESR) signal of these samples. It is found that the ESR spectrum of mech…
For epitaxial vanadyl and titanyl phthalocyanine films with Laue symmetry 4/mmm, second-harmonic generation (SHG) spectra due to only electric quadrupole and electric quadrupole coupling mechanisms were obtained under a suitable geometry, while the contributions of electric dipole, magnetic dipole, and magnetic dipole…
We have measured the polarized Raman cross sections and depolarization ratios of 16 fundamental modes of nickel octaethyltetraphenylporphyrin in a CS2 solution for 16 fundamental modes, i.e., the A1g-type vibrations ν1, ν2, ν3, ν4, ν5, and φ8, the B1g vibrations ν11 and ν14, the B2g vibrations ν28, ν29, and ν30 and th…
Dielectric measurements were carried out on viscous toluene covering a frequency range from 0.1 Hz to 1 MHz. In order to suppress the pronounced crystallization tendency of this supercooled liquid it was contained in thin walled capillaries with outer diameters of 300 μm. From the temperature dependence of the charact…
The concept of the time-of-flight (TOF) method for the determination of ionic carriers' mobility is presented. This method is used for the model system, the properties of which (including viscosity) change with time: the isothermally cured epoxy-amine system. It is demonstrated that the form of the TOF current signals…
Changes in the physical and mechanical behavior induced by two sterilization methods, gamma irradiation and ethylene oxide, were determined on two commercial medical-grade segmented polyurethanes. The two materials have different chemical composition: one is an aromatic poly(ether urethane urea), BiospanTM, and the ot…
The inter–relationships of alloy composition, film composition and ionic transport for formation of amorphous anodic oxide films are addressed quantitatively through systematic study of sputter–deposited Al–Ta alloys containing up to 39 at.% Ta. The work reveals the dependence of electric field, ionic transport number…
In this paper we report on the angle-resolved ultraviolet photoelectron spectroscopy on ultrathin films of bis(1,2,5-thiadiazolo)-p-quinobis (1,3-dithiole) (BTQBT) deposited on a MoS2 surface with synchrotron radiation, and describe the quantitative analysis of the angular distribution of photoelectron from the highes…
The catalytic mechanisms of triphenyl bismuth (TPB), dibutyltin dilaurate (DBTDL) and their combination have been studied in a model polyurethane reaction system consisting of copolyether (tetrahydrofuran–ethyleneoxide) and N-100; NMR spectroscopy was used to detect the associations between reactants and catalysts. A…
We show that, under equilibrium conditions, an anisotropic phase–field model of a diffuse interface leads to the notion of a divergence–free tensor, whose components are negligible away from the interface. Near the interface, it plays the role of a stress tensor, and involves the phase–field generalization of the Cahn…
Polypropylene/wood fiber composites were prepared at three different temperatures: 170°C, 180°C, and 190°C. The surface of wood fibers was modified through the use of silane coupling agents and/or coating with polypropylene or maleated polypropylene. The fiber coating was performed by propylene polymerization in the p…
In this paper, we present quantitative data on the amplification behaviour of alternative imaging gases in environmental SEM and describe the experimental methods used to obtain them. We investigated the gases' amplification abilities over the pressure range 0 - 12 Torr with respect to the primary beam energy, detecto…
This review is devoted to the angular selectivity that can be obtained in thin films prepared under conditions such that they contain inclined absorbing regions of sizes much smaller than the wavelength of visible light. The films are of considerable interest as window coatings for energy-conscious architecture and, p…
Coating of various surfaces and colloidal particles with flexible polymers greatly reduces adsorption and increases biological compatibility of surfaces and stability of colloidal particles. In addition, the immunogenicity and antigenicity of such particles decreases drastically. These findings are extremely important…
Chorismate mutase acts at the first branchpoint of aromatic amino acid biosynthesis and catalyzes the conversion of chorismate to prephenate. Comparison of the x-ray structures of allosteric chorismate mutase from the yeast Saccharomyces cerevisiae with Escherichia coli chorismate mutase/prephenate dehydratase suggest…
The safety of the PEGs has been studied and reported for over fifty years. Despite the fact that PEGS are generally recognized as safe, there is a paucity of recent literature on this topic. In this chapter we review the literature from early studies, and present new information on the safety of two different PEG poly…
The surface force apparatus was used to measure directly the molecular forces between streptavidin and lipid bilayers displaying grafted Mr 2,000 poly(ethylene glycol) (PEG). These measurements provide direct evidence for the formation of relatively strong attractive forces between PEG and protein. At low compressive…
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
The chemistry and biological applications of polyethylene glycol (or "PEG") have been the subject of intense study both in academics and in industry. The current volume contains 28 chapters dedicated to providing a review of the major aspects of the topic. In this introductory chapter we highlight recent developments…