Materials Literature
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Abstract Polymeric hindered amine light stabilizers (HALSs), in which the HALS functionality was attached to the terminal isocyanate chain end of poly(styryl‐ co ‐styryl isocyanate), were synthesized by a two‐step process. First, cinnamoyl azide was prepared and copolymerized with styrene by a free‐radical copolymeriz…
Chevron structures adopted by confined smectic liquid crystals are investigated via molecular dynamics simulations of the Gay-Berne model. The chevrons are formed by quenching nematic films confined between aligning planar substrates whose easy axes have opposing azimuthal components. When the substrates are perfectly…
Abstract The heterogeneous polymerization of vinyl chloride monomer (VCM), with n ‐butane as the reaction medium, was used to prepare poly(vinyl chloride) (PVC) resins. The particle features of the resulting resins and the particle formation mechanism of the polymerization process were investigated. The PVC resins pre…
Alanine racemase (AlaR) is a bacterial enzyme that catalyzes the interconversion of L- and D-alanine, which is an essential constituent of the peptidoglycan layer of the bacterial cell wall and requires pyridoxal 5'-phosphate (PLP) as a cofactor. The enzyme is universal to bacteria, including mycobacteria, making it a…
We substitute Ga for Mn in the ${\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{MnO}}_{3}$ compound to see how magnetic and atomic disorder affects the properties of this system. Ga doping gives rise to minor structural effects in the ${\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Ga}}_…
Abstract Hydrogenation of nitrile–butadiene rubber latex was carried out using hydrazine and hydrogen peroxide, with copper sulfate as catalyst and without pressurized hydrogen and organic solvent. A special inhibitor was used during hydrogenation to reduce gel formation. Various hydrogenation conditions were studied.…
NaAlH 4 is considered as a promising material for onboard storage of hydrogen. It is generally thought that high temperature (>120 °C) and high pressure (>15 MPa) are needed for rehydrogenation of dehydrogenated NaAlH 4 . However, for practical application, reducing the rehydrogenation temperature and pressure as much…
MCM-48 samples containing uranium (U−MCM-48) to the extent of 1 to 6 wt % were synthesized hydrothermally and characterized using powder XRD, 29 Si MAS NMR, FTIR spectroscopy, DR UV−Vis spectroscopy, N 2 sorption, and TEM techniques. These analyses confirmed the formation of an ordered cubic-phase MCM-48 mesomaterial…
Abstract Polythiophene (PTh) films were prepared by the electrochemical polymerization of thiophene in acetonitrile solution with boron fluoride–ethyl ether (BFEE) as the electrolyte. The electropolymerization processes were investigated by cyclic voltammetry. The onset potential of the electropolymerization decreased…
In a recent Physical Review Letter [1] Garcia and Nieto Vesperinas (GNV) dispute the claim of perfect lensing made in [2]. The thrust of the GVN paper is that the solutions proposed in [2] imply infinite energy density and are therefore inadmissible. They claim that finite absorption leads to catastrophic collapse of…
We report in situ observations of modifications in silicate glasses using electron-energy-loss spectrometry with a small-probe (2.2 \AA{}) scanning transmission electron microscope. Two silicate glasses ${\mathrm{C}\mathrm{a}\mathrm{O}\ensuremath{-}\mathrm{A}\mathrm{l}}_{2}{\mathrm{O}}_{3}\ensuremath{-}{\mathrm{SiO}}_…
ZnO-based organic/inorganic hybrid semiconductor compounds have been grown heteroepitaxially in one step at low temperature by a simple electrochemical method from an oxygenated zinc chloride aqueous solution. The substrate is GaN(0001) single crystals, and the organic compound is a dye, eosin Y, dissolved in the depo…
The self-diffusion and tracer diffusion of asymmetric poly(ethylene- alt -propylene- b -dimethylsiloxane), PEP−PDMS, copolymers were measured using forced Rayleigh scattering. Diffusion measurements were made in the disordered state, in disordered micelles, and in the body-centered-cubic (bcc) sphere phase. The FRS in…
Ordered nanorod (∼φ50 nm) arrays of TiO 2 −Ru and TiO 2 −RuO 2 embedded in porous alumina films were prepared from sputtered Al/ITO films on glass substrates through successive processes of anodization and cathodic electrodeposition. The microstructure of the nanorod arrays was investigated by field-emission scanning…
Abstract In this study, the influence of chlorinated polyethylene (CPE) and acrylonitrile–butadiene–styrene copolymer (ABS) on the mechanical properties of poly(vinyl chloride) (PVC)/CPE and PVC/ABS hybrids were examined. The experimental results show that the toughness of the hybrids could be modified greatly by the…
Abstract Polyvinylpyrrolidone (PVP) is characterized by its K ‐value, which is a function of the average molecular weight, the degree of polymerization, and the intrinsic viscosity. The viscosity was measured for aqueous PVP solutions with K ‐values ranging from 92.1 to 95.4 and with concentrations from 2 to 3 weight…
A new synthetic route for the synthesis of polyisobutylene (PIB) stars and PIB-poly(methacrylate) block copolymers was developed by combining living carbocationic and anionic polymerizations. Rapid and quantitative monoaddition of thiophene to living PIB chains has been observed in conjunction with TiCl 4 as Lewis aci…
Abstract We used silica particles as a porogen to prepare macroporous chitosan membranes and subsequently prepared macroporous chitosan/Cu(II) affinity membranes for urea adsorption. The morphology, porosity, Cu(II) adsorption capacity, and swelling ratio of the macroporous membrane were measured. SEM photographs show…
A novel general route to substituted meso-tetraaryltetra[2,3]naphthaloporphyrins (Ar(4)TNP) and meso-tetraaryloctamethoxytetra[2,3]naphthaloporphyrins (Ar(4)(MeO)(8)TNP) via oxidative aromatization of nonaromatically fused porphyrin precursors is described. Ar(4)(MeO)(8)TNPs exhibit more red-shifted absorption bands t…
We investigate the atomistic mechanism of yield to mechanical tension in boron nitride nanotubes. The formation energy of the first emerging defect is computed by accurate ab initio calculations. Its susceptibilities to mechanical tension is further evaluated in an economical fashion, when only load-free clusters need…