Materials Literature
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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…
Abstract Poly(butylene succinate) (PBS) and its copolymers, poly(butylene succinate‐ co ‐adipate) (PBSA) and poly(butylene‐ co ‐hexylene succinate) (PBHS), were synthesized by direct polyesterification of corresponding diols and dicarboxylic acids. Dimethyl benzene was used as solvent and water‐removing agent. Several…
We prepare a series of mixed brushes of two incompatible polymers, polystyrene (PS) and poly(2-vinylpyridine) (P2VP) grafted by end groups to Si wafers from carboxyl-terminated P2VP ( M W (P2VP) 42 kg/mol) and carboxyl-terminated PS. The molecular mass of PS ranged from 2.98 to 75 kg/mol. The mixed brushes are bidispe…
Silver nanostructures deposited on glass showed luminescent blinking when excited at a high 442 nm irradiance. The irradiance required to photoactivate the silver, was dependent on the nature of the silver nanostructures. Silver fractal-like structures were found to be highly emissive, requiring only ≈30 W/cm(2) for p…
The class II PHA (polyhydroxyalkanoate) synthases [PHA(MCL) synthases (medium-chain-length PHA synthases)] are mainly found in pseudomonads and catalyse synthesis of PHA(MCL)s using CoA thioesters of medium-chain-length 3-hydroxy fatty acids (C6-C14) as a substrate. Only recently PHA(MCL) synthases from Pseudomonas ol…
Abstract Poly(urethane‐isocyanurate)s were synthesized by reacting toluene diisocyanate and poly(propylene glycol) with various stochiometric ratios (1–3) in the presence of different concentrations of dibutyltin dilaurate (DBTDL) and ferric acetylacetonate (FeAA). The influence of the NCO/OH ratio and the catalyst ty…
Abstract Poly(ethylene terephthalate) waste materials were depolymerized by ethylene glycol (EG), diethylene glycol (DEG), and propylene glycol (PG) in the presence of a novel catalytic system: titanium (IV)‐phosphate. The new catalyst was synthesized through a reaction of TiCl 4 with triethyl phosphate (C 2 H 5 O) 3…
Recent experiments showed that the last, single channel conductance step in monatomic gold contacts exhibits significant fluctuations as a function of stretching. From simulations of a stretched gold nanowire linked to deformable tips, we determine the distribution of the bond lengths between atoms forming the nanocon…
The vibrational density of states (VDOS) of nanoclusters and nanocrystalline materials are derived from molecular-dynamics simulations using empirical tight-binding potentials. The results show that the VDOS inside nanoclusters can be understood as that of the corresponding bulk system compressed by the capillary pres…
Circular dichroism (CD) spectra of chiral bare and thiol-passivated gold nanoclusters have been calculated within the dipole approximation. The calculated CD spectra show features that allow us to distinguish between clusters with different indexes of chirality. The main factor responsible of the differences in the CD…