Materials Literature
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Catalyzed transesterification in the melt is used to produce diblock copolymers of poly([R]-3-hydroxybutyric acid), PHB, and monomethoxy poly(ethylene glycol), mPEG, in a one-step process. Bacterial PHB of high molecular weight is depolymerized by consecutive and partly simultaneous reactions: pyrolysis and transester…
The crystal structure of glutamine synthetase (GS) from Mycobacterium tuberculosis determined at 2.4 Å resolution reveals citrate and AMP bound in the active site. The structure was refined with strict 24-fold noncrystallographic symmetry (NCS) constraints and has an R -factor of 22.7% and an R -free of 25.5%. Multico…
An ab initio MO study on a model system for photochromic compounds containing a dithienylethene unit is presented. On the basis of the obtained potential energy profile, a rationalization is provided for the proposed mechanism of the experimentally observed stepwise multiphoton process in the ring-opening cycloreversi…
Organized multilayers of nanoparticles (9-, 20-, and 45-nm-diameter silica or 12-nm magnetite) and glucose oxidase (GOx) were assembled in alternation with oppositely charged polyelectrolytes on 420-nm latex particles. Stepwise growth of the multilayer films on latex was confirmed by microelectrophoresis and transmiss…
Fluoroalkylsilanes (FAS) prove to be an interesting water-repellent coating for the recently discussed “superhydrophobic surfaces”. The FAS investigated here form a self-assembled monolayer when brought into contact with a surface. They arrange at a high degree of orientation with their molecular axis perpendicular to…
Well-ordered mesostructured silica and titania films were prepared using poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) triblock copolymer species (Pluronic P123) as the structure-directing agents. By varying the volume ratio between the copolymer and inorganic components of the precursor solution, si…
The best current way to prepare Au/TiO 2 catalysts is the method of deposition−precipitation with NaOH (DP NaOH) developed by Haruta and co-workers. With this method, it is possible to obtain small gold metal particles (2−3 nm), but the corresponding gold loading remains rather low (∼3 wt %). The main goal of this wor…
Carbon nanotubes are quasi one-dimensional nanostructures with unique eletrical prroperties that make them prime candidates for molecular electronics, which is certainly a most promising direction in nanotechnology. Early theoretical works predicted that the electronic properties of "ideal" carbon nanotubes depend on…
We report a new nonwrapping approach to noncovalent engineering of carbon nanotube surfaces by short, rigid functional conjugated polymers, poly(aryleneethynylene)s. Our technique not only enables the dissolution of various types of carbon nanotubes in organic solvents, which represents the first example of solubiliza…
The crystal structure of the title compound, [FeCl(2)(C(4)H(8)O(2))(H(2)O)(2)](n), contains six-coordinate Fe(II) atoms in approximately octahedral environments. The Fe(II) atoms have 1 symmetry, i.e. all pairs of identical ligands are trans. The structure consists of polymeric chains made up of dioxane molecules, in…
In the absorption spectrum of the crystal there was stated the presence of Ti3+ ions at octahedral Ga positions in strong crystal field. Ti3+ ions arise due to some reducing conditions of the crystal growth. It was found that electron delocalization at higher temperature, e.g. In oxidation-reduction reaction: Ti4+ + e…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTPreparation and Rheological Properties of Emulsion GelsAnne Koenig, Pascal Hébraud, and Patrick PerrinView Author Information Laboratoire de Physico-Chimie Macromoléculaire, UMR 7615, Ecole Supérieure de Physique et Chimie de Paris (ESPCI), CNRS, Université Pierre et Marie Curi…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSynthesis of AgBr and SnO2 Microwires Induced by Mixed Surfactant Nematic Liquid Crystalline PhasesTsuyoshi Kijima, Takayuki Ikeda, Mitsunori Yada, and Masato MachidaView Author Information Department of Applied Chemistry, Faculty of Engineering, Miyazaki University, Miyazaki,…
The effect of rare earth and transition metal luminescent impurities on the optical properties of As<SUB>2</SUB>S<SUB>3</SUB> glass is studied in a wide spectral region. The Raman, IR, band- to-band and edge absorption spectroscopies are employed to obtain information about the incorporation of impurity ions in the ho…
A general, efficient method was developed to incorporate a variety of second metal ions into ultrathin TiO 2 films. The thin films were first prepared by the surface sol−gel process from a mixture of the matrix-forming titanium alkoxide and template magnesium alkoxide. Mg 2+ ion was removed by acid/base treatment, for…
The reaction of M(BF(4))(2).xH(2)O (M = Co, Ni, and Cu) and HC(3,5-Me(2)pz)(3) in a 1:2 ratio yields [Co[HC(3,5-Me(2)pz)(3)](2)](BF(4))(2) (2), [Ni[HC(3,5-Me(2)pz)(3)](2)](BF(4))(2) (3), and [Cu[HC(3,5-Me(2)pz)(3)](2)](BF(4))(2) (4). Over the temperature range from 5 to 350, 345, or 320 K, Curie law behavior is observ…
Modern combat aircraft are required to achieve aggressive maneuverability and high agility performance, while maintaining handling qualities over a wide range of flight conditions. Recently, a new adaptive-structural concept called variable stiffness spar is proposed in order to increase the maneuverability of the fle…
From a structural analysis using low-energy ion scattering spectroscopy, it is shown that Cu−phthalocyanine (CuPc) molecules adsorb on the Fe(100) surface with their planes parallel to the surface when the film thickness is one monolayer, while the structure of the film becomes disordered with an increase in the thick…
Simultaneous catalytic removal of NO x, SO x, and CO under simulated FCC regenerator conditions was investigated over mixed oxide catalysts CuMgAlO (Cu-cat), CeMgAlO (Ce-cat), and CuCeMgAlO (CuCe-cat), which were prepared by coprecipitation and characterized by XRD, XPS, and N 2 adsorption−desorption. At low temperatu…
The astonishing results of P. M. Ajayan et al. (“Nanotubes in a flash—ignition and reconstruction,” Brevia, 26 April, p. [705][1]) demonstrating ignition of carbon nanotubes after exposure to a photographic flash inspired us to make further explorations along the same lines. We found that similar effects can be obtain…