Materials Literature
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NMR on ${}^{57}\mathrm{Fe}$ nuclei was measured in two single crystals of magnetite between 4.2 and 135 K (temperature of the Verwey transition ${T}_{V}=121.5$ and 123.9 K). We were able to register all lines detected at 4.2 K also at higher temperatures up to ${T}_{V}.$ The spectra are compatible with the space group…
Mesostructured silica functionalised with the dye moiety, (2,4-dinitrophenylamine), has been prepared with bimodal pore size distribution. Co-condensation of tetraethoxysilane and 3-(2,4-dinitrophenylamino)propyltriethoxysilane was used to covalently couple the organic chromophore into the wall structure of a silica m…
We report that ``ferroelectric relaxor'' behavior is induced by doping Bi in quantum paraelectric ${\mathrm{SrTiO}}_{3},$ and doping Ce in typical ferroelectric ${\mathrm{BaTiO}}_{3}.$ The present results show that the ``ferroelectric relaxor'' state may exist no matter whether the matrix is ferroelectric or paraelect…
The cellular silicon, nitrogen, and carbon content and the kinetics of silicic acid use were determined for Thalassiosira weissflogii grown under nutrient-replete, iron-deficient, and zinc-deficient conditions to assess the effect of metal deficiency on dlatom silicon metabolism. Iron-and zinc-deficient T weissflogi~…
Automotive emissions are severely regulated. Since 1980, a three-way catalyst (TWC) has been used to convert harmful emissions of hydrocarbons, carbon monoxide, and oxides of nitrogen into less harmful gases in order to meet these regulations. The TWC's efficiency of conversion of these gases is primarily dependent on…
The cell size of DVB–VBC PolyHIPEs decreases with increasing VBC content, which appears to be due to the adsorption of VBC at the emulsion interface leading to a lower interfacial tension and a smaller droplet size.
Research Article| January 01, 2000 Solid-Solution Solubilities and Thermodynamics: Sulfates, Carbonates and Halides Pierre Glynn Pierre Glynn U.S. Geological Survey, 432 National Center, Reston, Virginia 20192 Search for other works by this author on: GSW Google Scholar Author and Article Information Pierre Glynn U.S.…
Pt and Pd nanoparticles can be modified with surface-attached cyclodextrin receptors leading to water-soluble materials that exhibit catalytic activity for the hydrogenation of allylamine.
A new UV-blocking material consisting of cerium oxide (ceria) and turbostratic boron nitride (t-BN) has been synthesized. The surface of the ceria powders was coated with a t-BN layer by means of reaction between boric acid and urea on the surface of ceria. The thickness of the t-BN layer estimated by high resolution…
Segmented thermoplastic polyurethanes (TPU)s with amorphous soft segments from the reaction of hexamethylene diisocyanate and 1,2-butanediol and crystalline hard segments from 4,4′-methylenediphenyl diisocyanate and 1,6-hexanediol showed sharp glass-transition temperatures that could be used as shape-recovery temperat…
Fluorexon (4′,5′-bis[N,N-bis(carboxymethyl)aminomethyl]fluorescein) forms stable, water-soluble complexes with lanthanide ions. The complexes with neodymium(III), erbium(III) and ytterbium(III) display sensitised near-infrared lanthanide luminescence upon excitation of the fluorexon with visible light. The photosensit…
The structural and magnetic transitions in two ${\mathrm{Mn}}^{3+}/{\mathrm{Mn}}^{4+}(1:1)$ systems have been investigated using neutron diffraction and electron microscopy. In ${\mathrm{Pr}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3},$ the charge and orbital order develops in the paramagnetic phase of Pnma symmetry b…
Monodispersed cerium(IV) oxide (CeO2) particles composed of an agglomeration of primary nanocrystalline particles with a cubic fluorite structure could be synthesized from relatively concentrated cerium(IV) sulfate solutions up to 0.5 mol dm−3 by thermal hydrolysis at 120 to 240 °C. The influences of the presence of u…
Very strong, broad photoluminescence (PL) in the near infrared is displayed by colloidal HgTe nanocrystals. However, they are not stable over time—the PL moves to longer wavelengths, accompanied by an apparent drop in the quantum efficiency—which causes concern for the use of these materials in device applications. He…
Several de novo designed ionic peptides that are able to undergo conformational change under the influence of temperature and pH were studied. These peptides have two distinct surfaces with regular repeats of alternating hydrophilic and hydrophobic side chains. This permits extensive ionic and hydrophobic interactions…
Osmoprotectants exogenously supplied to a hyperosmotic culture medium are efficiently imported and amassed by stressed cells of Escherichia coli. In addition to their evident role in the recovery and maintenance of osmotic balance, these solutes should play an important role on the behavior of cellular macromolecules,…
Current density and pH mapping techniques have been used to characterize the chemical and electrochemical phenomena which occur on the cut edge of galvanized steel. pH variations between 7 and 11 were observed, primarily due to the formation of hydroxyl ions by the cathodic reaction. Zinc‐based corrosion products prec…
Polyaniline (PANI) protonated with camphorsulfonic acid (CSA) is one of the most promising conductive polymers due to its relatively high crystallinity, high electrical conductivity, and the metallic characteristics at high temperatures, i.e., a positive temperature coefficient of resistivity. The crystalline structur…
Photochromic molecules are of great potential importance for optoelectronic devices. This communication presents the preparation of two new spiropyrans that display the first reported crystalline-state photochromism. UV irradiation of the pale yellow form produces the highly colored red form, both in the solid state a…
Alkenes and allylic alcohols have been epoxidized in an ambient-temperature ionic liquid for the first time using methyltrioxorhenium (MTO) and urea hydrogen peroxide; excellent conversions and selectivities for the epoxides of a wide number of substrates were observed.