Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Protonated poly(propylene imine) dendrimers (Astramol) of five generations: DAB-dendr-(NH2)x (where x=4, 8, 16, 32 or 64) are sorbed by slightly cross-linked polyanionic hydrogels: poly(sodium acrylate) and poly(sodium 2-acrylamido-2-methylpropane sulfonate). As a result highly swollen original hydrogel transforms int…
UV irradiation of a polyphotochromic molecule bearing a spironaphthoxazine unit linked to a naphthopyran by a Z-ethenic bridge produces several interconverting nonequilibrium dihydrophenanthrenic photocyclized isomers. A quantitative kinetic analysis of the thermal evolution after photocyclization has been performed u…
Abstract The electrochemical and electrocatalytic behavior of electrodes modified with a Co/Al‐NO 3 hydrotalcite (HT) has been investigated and compared with that displayed by Ni/Al‐NO 3 HT modified electrodes. Mono and polyhydric compounds have been tested to study electrocatalysis. At Co/Al‐NO 3 HT modified electrod…
The magnetic phase separation in single crystals of the Pr0.67Ca0.33MnO3 manganites is studied using polarized small angle neutron scattering. The measured spectra give a fractal dimension consistent with a configuration in ferromagnetic filaments of nanometric diameter. We argue here that localized charge carriers ho…
We report a numerical study of the primary crystal nucleation of diblock copolymers in a lamellar phase. Only one of two polymer blocks is crystallizable; the other is maintained in a glassy state. We find that crystals in this lamellar geometry tend to nucleate with the chain axis perpendicular to the lamellar plane.…
A covalently tethered dyad containing the azulene (Az) and zinc tetraphenylporphyrin (ZnP) chromophores has been synthesized and its excited-state dynamics investigated, using the tether-substituted monochromophoric species as reference compounds. One photon excitation of the dyad at 270 nm results in selective popula…
Carbon disulfide, CS 2, mp = 161.7 K, has been crystallized in situ in a diamond-anvil cell at 295 K and 1.26 GPa to give an orthorhombic Cmca structure. No phase transitions occur with further increasing pressure till the polymerization onset at 8 GPa. The crystal structure was determined by direct methods from singl…
Molecular dynamics (MD) simulations were used to characterize the non-cooperative denaturation of the molten globule A-state of human alpha-lactalbumin by urea. A solvent of explicit urea and water molecules was used, corresponding to a urea concentration of approximately 6M. Three simulations were performed at temper…
The short-chain (n approximately equal to 50) homopolymer poly(L-cysteine) (PLC) has been previously studied for use as a novel metal chelator. PLC exhibits reversible oxidation-reduction chemistry involving the thiol groups of the cysteine (Cys) residues. Previously, chemical oxidation of the PLC immobilized on silic…
We present experimental evidence of zenithal gliding of the nematic easy axis on a polyimide surface. The reorientation dynamics of the easy axis under external torque, and its relaxation, are extremely slow processes which cannot be described by a single exponential time. They show similarities with aging phenomena p…
ZnO layers doped simultaneously with Ga and N (codoping), and magnetic elements (V, Co) were characterized by Raman scattering to study their structural stability. Five impurity modes were observed in range 200–900 cm −1 in the doped samples, and showed characteristic variation with the doping level. It is shown that…
An incommensurate composite phase with a monoclinic host-guest structure, designated $\mathrm{Sb}\text{\ensuremath{-}}\mathrm{IV}$, is found between the previously known $\mathrm{Sb}\text{\ensuremath{-}}\mathrm{I}$ and $\mathrm{Sb}\text{\ensuremath{-}}\mathrm{II}$ phases, and an incommensurate to incommensurate transi…
The continuous synthesis of fullerenes and carbon nanotubes (CNTs) in induction plasmas at the 40-kW plate power level has been studied. Kinetics calculations were conducted to predict the conditions for fullerenes formation at the high plasma temperatures. “Carbon black-iron” powder mixtures were used as starting mat…
Crystallization of helical polymers is a very big challenge for molecular simulation. It involves many significant issues, such as folding in biomolecules and molecular recognition during crystal growth. Though direct molecular simulations of the process still involve very difficult problems, we here report our recent…
Nanocrystal formation in annealed a-SiO0.17N0.07:H films, Kohli, Sandeep, Theil, Jeremy A, Dippo, Patricia C, Jones, K M, Al-Jassim, Mowafak M, Ahrenkiel, Richard K, Rithner, Christopher D, Dorhout, Peter K
Room temperature electroluminescence has been demonstrated from undoped silicon nanowires that were grown from disilane. Ensembles of nanowires were excited by capacitively coupling them to an ac electric field. The emission peak occurred at about 600 nm from wires of average diameter of about 4 nm. The emission appea…
A layered nanocomposite with poly(diallyldimethylammonium), PDDA, intercalated between manganese oxide layers can be formed on a platinum electrode in a thin film form through a direct electrochemical route. The process involves a potentiostatic oxidation of aqueous Mn(2+) precursors in the presence of PDDA by applyin…
The shape and stability of a liquid drop on a bare planar solid surface are analyzed by minimizing its total potential energy calculated microscopically. The solution of the obtained differential equation for the drop profile shows that there is a rapid variation of the angle between the tangent to the profile and the…
Electromigration phenomena in metallic lines are studied by using a biased resistor network model. The void formation induced by the electron wind is simulated by a stochastic process of resistor breaking, while the growth of mechanical stress inside the line is described by an antagonist process of recovery of the br…
We report a chemical route capable of making template-free, pure, and oriented polyaniline (PANI) nanotubes (60–130 nm in diameter) in bulk quantities containing azobenzene groups, which exhibited trans–cis photoisomerization upon irradiation with UV light. The specific morphology of the oriented PANI nanotubes with h…