Materials Literature
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Two new classes of (HCN)(n)...Li and Li...(HCN)(n) (n = 1, 2, 3) clusters with the electride characteristic are formed in theory by the metal Li atom attaching to the (HCN)(n) (n = 1, 2, 3) clusters. Because of the interaction between the Li atom and the (HCN)(n) part, the 2s valence electron of the Li atom becomes a…
Hyperbranched glycopolymers were synthesized by self-condensing vinyl copolymerization (SCVCP) of an acrylic AB* inimer, 2-(2-bromopropionyloxy)ethyl acrylate (BPEA), with 3- O -acryloyl-1,2:5,6-di- O -isopropylidene-α- d -glucofuranoside (AIGlc) via atom transfer radical polymerization (ATRP), followed by deprotectio…
We propose a generalized London theory that can correctly describe the longitudinal and transverse responses of conventional superconductors to an electromagnetic field. The continuity equation is satisfied by use of a special gauge for the scalar and vector potentials. Our phenomenological theory provides a simple ex…
Based on the interpretation of X-ray diffraction data reported for crystals of the poly-L-glutamine-rich 19-peptide D(2)Q(15)K(2), Perutz et al. (Proc. Natl. Acad. Sci. USA 2002, 99, 5591-5595) proposed that hollow, water-filled nanotubes are the basic structural motif of amyloid fibers. We are able to offer an altern…
A new and facile synthetic route of ordered mesoporous carbon with polypyrrole as carbon precursor has been developed. The mesoporous silica host is first impregnated with ferric chloride, which serves as the oxidant for the vapor-phase oxidative polymerization of pyrrole vapor at room temperature. Such a stoichiometr…
A method for the ultrastructural investigation of fiber cross-sections based on atomic force microscopy in combination with image analysis is presented. A uniform distribution of pores across the matrix material within the fiber wall was revealed by impregnation of pulp fibers with poly(ethylene glycol). The effects o…
Thermally evaporated silver nanoparticles on conducting substrates spontaneously evolve in size when immersed in pure water. The process was studied using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and optical absorption spectroscopy. The particles are proposed to reform through an ele…
Postsynthesis pore expansion of as-synthesized MCM-41 silica using N, N -dimethyldecylamine affords material A, with open pore structure and readily accessible amine groups. The selective removal of the occluded amine gives rise to B, a highly porous, hydrophobic material with large surface area and pore volume. Mater…
Point defect mediated diffusion of impurities in crystalline materials involves a sequence of several processes, which are repeated in varying combinations a multiple number of times. The concept of “activation energy” has been borrowed from simple chemical reactions, where the reactants are postulated to form an acti…
We have demonstrated the interest of using Zr-Ce mixed oxides as supports for the system H3PW12O40 x 6H2O (HPW) and Pt for the storage (absorption into HPW and adsorption on Zr-Ce support)-reduction of NOx. Zr-Ce oxides adsorb NOx (mainly NO2) as nitrates, which are desorbed thermally as NO2 and NO (12 mg of NOx x g(-…
The use of enzymes in conjunction with inorganic photocatalysts requires stability against photooxidation. In this paper, we describe enhanced stabilization of a model enzyme, chymotrypsin, to photooxidation driven by titanium dioxide exposed to ultraviolet light (TiO(2)-UV). Stabilization is achieved conjugating the…
A well-posed moving boundary-value problem, describing the dynamics of curved interfaces and surfaces associated with voids and/or cracks that are interacting with grain boundaries, is obtained. Extensive computer simulations are performed for void configuration evolution during intergranular motion, under the actions…
The effect of adsorbed water on the signal of scanning nonlinear dielectric microscopy (SNDM) is reported. By measuring SNDM image variation under various measurement conditions and by computing the theoretical SNDM signal corresponding to these conditions, we verified that the adsorbed water strongly affects the sign…
Fe 57 transmission Mössbauer spectroscopy (TMS) and back scattered conversion electron Mössbauer spectroscopy (CEMS) measurements were carried out on Fe-filled multiwalled carbon nanotubes (Fe-MWCNTs) grown by chemical vapor deposition with ferrocene as precursor. Samples of Fe-MWCNTs material deposited on the inner w…
Oxygen radicals pregrowth treatment and surface nitridation were used to eliminate Zn-polar inversion domains and control the growth of single-domain O-polar ZnO film on sapphire (0001) substrate by rf plasma-assisted molecular beam epitaxy. We found that the formation of oxygen-terminated sapphire surface prior to ni…
Cooperativity between metal centers and a bridging radical ligand, reflected by ferromagnetic exchange coupling, was studied with the dicopper complex shown. The stability, and thus the reactivity of the complex, is finely tuned by both the nuclearity of the complex and the nature of the coordinating solvent X.
We address here a theoretical study on the role played by external magnetic and electric fields on the electronic properties of toroidal carbon nanotubes. A single-$\ensuremath{\pi}$ band tight-binding calculation is adopted and real-space renormalization techniques are used to obtain electronic energy spectra. Induce…
Photoinduced phase transition from a charge-density-wave (CDW) state to a Mott-Hubbard (MH) insulator is studied theoretically. According to the very recent experiment [H. Matsuzaki et al., Phys Rev B 70, 035204 (2004)], a quasi-one-dimensional Br-bridged Pd compound, $[\mathrm{Pd}{(\mathrm{chxn})}_{2}][\mathrm{Pd}{(\…
We use a micromechanics approach to study the magnetoelectric (ME) properties of the piezoelectric/magnetostrictive composite with a 2–2 laminate structure and a 3–1 fibrous structure. It is found that the 3–1 composite has a higher ME coefficient than the 2–2 one, if the volume ratio of piezoelectric material is the…
The orientation distributions of α-Al 2 O 3 textured ceramics are determined from neutron diffraction spectra. A curved position-sensitive detector coupled to a tilt angle (χ) scan allowed the whole diffraction pattern treatment in the combined Rietveld−WIMV−Popa algorithm. Four textured alumina ceramics were prepared…