Materials Literature
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Cellular polypropylene (PP) films were treated with sulfur hexafluoride (SF6) gas in order to study the SF6 penetration behaviour and optimize the electric charging conditions. There were differences in the penetration of SF6 for different cellular PP materials, depending on the microscopic properties, which manifest…
The dependence of the polarization of ferroelectric perovskite thin films on the film thickness is explicitly calculated by using a generalized Landau–Ginzburg–Devonshire thermodynamic theory. Both residual stress and stress relaxation in the films have a significant effect on the thickness-dependent polarization. Our…
Individual effective glass transitions of components in miscible blends of polystyrene/poly(vinyl methyl ether), poly( o -chlorostyrene)/poly(vinyl methyl ether), and poly(styrene- block - n -butyl acrylate)/polystyrene were detected by temperature-modulated differential scanning calorimetry. These blends apparently s…
New water-soluble bimetallic peroxo-tartrato complexes of niobium(V) and/or tantalum(V) have been prepared, characterized from the structural and spectroscopic point of view, and used as molecular precursors for Nb-Ta mixed oxides. Two new homometallic complexes, (gu)5[Nb2(O2)4(tart)(Htart)] x 4H2O (1a) and (gu)6[Ta2(…
The transport of charge across symmetrical low-angle [001] tilt grain boundaries in Fe-doped SrTiO3 was examined. Grain boundary resistances were obtained from impedance spectroscopy measurements on bicrystals with misorientation angles θ=2.3°, 5.4°, and 7.8° as a function of temperature and oxygen partial pressure. B…
The possible existence of a compensation effect, i.e. concurrent changes in activation energy and prefactor, is investigated for the hydrogenation and dehydrogenation kinetics of metal hydrides, by analyzing a series of reported kinetic studies on Mg and LaNi(5) based hydrides. For these systems, we find a clear linea…
meso-Aryl-substituted pentaphyrins were isolated in the modified Rothemund-Lindsey porphyrin synthesis as a 22-pi-electron N-fused pentaphyrin ([22]NFP5) and a 24-pi-electron N-fused pentaphyrin ([24]NFP5), which were reversibly interconvertible by means of two-electron reduction with NaBH4 or two-electron oxidation w…
The three-step manufacturing of bioinspired SiSiC/zeolite monoliths starting from native rattan stems is presented. Rattan-derived cellular SiSiC ceramics are prepared via a biotemplating liquid silicon infiltration process. MFI-type zeolite crystals are directly grown onto the ceramic substrate. SiSiC/zeolite composi…
Thin silica films with orthogonally aligned hexagonal close-packed cylindrical structure are synthesized by dip coating silica precursors and poly(ethylene oxide)-polyproplyene oxide (PEO-PPO) triblock surfactants (P123) onto modified glass slides. All films cast from this sol display 2D hexagonal pore structures (a a…
Enantioselective surfactant-templated thin films were fabricated through the sol-gel (SG) process. The enantioselectivity is general in the sense that it discriminates between pairs of enantiomers not used for the imprinting process. The chiral cationic surfactant (-)-N-dodecyl-N-methylephedrinium bromide (1) was used…
In Bacillus subtilis, the NADPH-dependent glyceraldehyde-3-phosphate dehydrogenase (GapB) and the phosphoenolpyruvate carboxykinase (PckA) enzymes are necessary for efficient gluconeogenesis from Krebs cycle intermediates. gapB and pckA transcription is repressed in the presence of glucose but not via CcpA, the major…
A molecular double-throw switch that employs a photochromic moiety to direct photoinduced electron transfer from an excited state donor down either of two pathways has been prepared. The molecular triad consists of a free base porphyrin (P) linked to both a C(60) electron acceptor and a dihydroindolizine (DHI) photoch…
Substantial alignment of isolated individual single-wall carbon nanotubes (SWNTs) has been achieved by mechanically stretching gelatin films filled with homogeneously dispersed SWNTs. Highly polarized absorption and photoluminescence are observed that are attributed to interband optical transitions in SWNTs. Sharp and…
Covalent ties: The polyoxometalate (nBu4N)3[(MeO)TiW5O18] is easily anchored to alkanol-functionalized surfaces of porous and single-crystal silicon (see picture, polyhedra: polyoxometalate, dark blue: Si surface). Scanning tunneling microscopy reveals the growth of 35–50 nm diameter islands on functionalized Si(111),…
The energy level alignment (see Figure) at interfaces between pentacene and thin films of conducting polymers (made from ethylenedioxythiophene and sulfonate moieties) is found to be independent of initial polymer work function or morphology. Interfacial chemical reactions control the energy level alignment, rather th…
We show that hydrogen-bonded multilayer thin film coatings assembled on colloidal particles can be used as templates for the in situ synthesis of nanoparticles. The concentration and size of nanoparticles grown within the coatings can be tuned by the number of loading cycles. The hydrogen-bonded multilayer thin films…
Nanostructural control of gallium oxide formation is achieved at low temperatures by the enzyme-catalyzed hydrolysis and polycondensation of gallium oxide precursors. Filaments of silicatein, a hydrolase originally discovered in a marine sponge, catalyze the hydrolysis of gallium(III) nitrate, producing oriented nanoc…
Photochromic conductivity modulation of conjugated polymers containing a diarylethene unit with high photochromic conversion ratios is described. The electrical conductivity can be switched quasi-reversibly from the bleached low-conductivity state (Figure, left) and the blue high-conductivity state (right) by alternat…
We have fabricated n-type carbon nanotube field effect transistors by choosing the contact metal. Single-walled carbon nanotubes were grown directly on a SiO2∕Si substrate by chemical vapor deposition using patterned metal catalysts. Following the nanotube growth, Ca contacts with a small work function were formed by…
Single- or multicolor-encoded microspheres are created by confining water-soluble CdTe nanocrystals with different sizes within hydrogel microspheres of N-isopropylacrylamide and 4-vinylpyridine copolymer based on the pH-responsive swelling behavior of the gel (see Figure). The emission intensity level and color of th…