Materials Literature
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The adsorptive and reactive behaviour of TiO2, SrTiO3 and SrO towards methanol have been investigated using temperature-programmed desorption and XPS. TiO2 was found to be reduced during the adsorption/desorption process and showed predominantly CH4 formation at low coverages. At higher coverages, alternative paths le…
The galvanic corrosion datafor couples between high alloy stainless steels and other metals in both natural and chlorinated sea water are reviewed. Recommendations for preventive measures are made for the major items used in sea water systems, i.e. valves, heat exchangers, and piping. Some service experiences are pres…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterpolymer complexation of poly(acrylic acid) and polyacrylamide: structural and dynamic studies by solution- and solid-state NMRFred O. Garces, K. Sivadasan, P. Somasundaran, and Nicholas J. TurroCite this: Macromolecules 1994, 27, 1, 272–278Publication Date (Print):Janua…
Natural polycrystalline graphite was compressed using a 6-8-type multianvil and a Drickamer cell, and the recovered samples were examined by x-ray diffraction and transmission-electron microscopy. Diamond was formed in the samples from 14\ensuremath{\sim}20 GPa and 800\ensuremath{\sim}1200 \ifmmode^\circ\else\textdegr…
Three spinels (MgAl2O4, ZnAl2O4 and CaAl2O4) have been synthesized using a sol–gel process coupled with supercritical drying. After calcination at 1000 K, specific areas as high as 300 m2 g–1 can be preserved. Deposition of copper oxide on such carriers leads to the formation of catalysts active in methane combustion.…
Matrix-isolation infrared spectra of trimethyl phosphate (TMP), triethyl phosphate (TEP), and tri- n-butyl phosphate (TBP), in argon and nitrogen matrices, are reported for the first time. The peak widths of the sharpest features in our matrix-isolated spectra are typically 2 cm −1 , compared with peak widths of 40 cm…
Abstract Powders and X-ray size single crystals of the rare earth disilicates RE 2 Si 2 O 7 (RE = La to Nd and Gd to Lu and Y) were synthesized from the melts in a fast crucible-free process. The purity and unit cell parameters of the disilicates were determined from Guinier photographs. Previously reported structure…
Trace elements can reduce the fracture resistance of Zr-2.5Nb pressure tubes. The effects of hydrogen as hydrides and oxygen as an alloy-strengthening agent are well known, but the contributions of carbon, phosphorus, chlorine, and segregated oxygen have only recently been recognized. Carbides and phosphides are britt…
Magnetic measurements and X-ray crystal analyses were carried out on iodide salts of p-N-alkylpyridinium α-nitronyl nitroxides [4-(4,4,5,5-tetramethyl-1-oxido-3-oxyl-4,5-dihydro-3H-imidazol-2′-yl)-1-R-pyridinium, with R = methyl (1+), ethyl (2+), n-propyl (3+) and n-butyl (4+)]. The strongly antiferromagnetic crystal…
Steroidal constituents from the roots and stems of Asclepias fruticosa L. were investigated separately. From the roots, twelve pregnane pentaosides and uzarigenin beta-sophoroside were isolated together with three known coroglaucigenin and corotoxigenin glycosides. Pregnane glycosides were composed of ikemagenin or ki…
Selective catalytic reduction (SCR) is a process in which nitrogen oxides (NO{sub x}) are removed by the injection of ammonia (NH{sub 3}) into the flue gas. Chemical reactions in the presence of a catalyst produce nitrogen and water vapour. The article discusses the design and operating experience of SCR systems for d…
MD films are adopted as matrices for the assembly of Pbl2 nanoparticles into a layer structure; UV–VIS and X-ray diffraction results prove that the multilayers formed have a well-defined layer structure.
Treatment of cyanoethylated tetrathiafulvalene-thiolates or cyanoethylated 1,3-dithiole-2-thione-4,5-dithiolate with one equiv. of caesium hydroxide hydrate selectively and in high yield produces the corresponding monocaesium salts, which can subsequently be alkylated.
Six polymer-supported MoVI catalysts have been prepared. Two involve supported aminomethyl-2-pyridine (AMP) ligands, and the other four various ligands based on imidazole. All catalysts are active in the epoxidation of propene using tert-butyl hydroperoxide in the liquid state at 80 °C and at a pressure of 400 psi (He…
Protein-stabilized food dispersions often contain a range of surface active species. Many of these are of low molecular weight and include lipids or food emulsifiers. Depletion measurements, fluorescence and fluorescence recovery after photobleaching (FRAP) studies have shown that competitive adsorption of these molec…
Electromigration, that is, the forced motion of metal ions under the influence of an electric field, is potentially one of the most pernicious failure mechanisms in interconnects of large scale integrated microelectronic devices. The momentum exchange between the electrons and the ions causes the latter at normal oper…
A unified model of ionic motion in glasses is presented which relates consistently the different quantities observed in nuclear-spin relaxation and electrical-conductivity relaxation due to thermally activated ionic diffusion. Corresponding experimental data obtained in a low-ionic-conductivity fluorozirconate glass a…
We have previously shown that some ellagitannins are potent inhibitors of protein kinase C (PKC). On the basis of this finding, several series of hexahydroxybiphenyl derivatives of ellagic acid were synthesized as simple analogs of these ellagitannins and were evaluated for their inhibitory effect against PKC. Compoun…
The inverse temperature transition exhibited by elastin-like polypeptides has been shown to provide a basis for an intriguing array of energy transduction processes. For example, the elastin poly(pentapeptide) 1 can be fabricated into cross-linked gels that remain swollen in water at temperatures below 25 °C but then…
Electrodeposition of several unary and layered double hydroxides has been achieved by electrogeneration of base from the cathodic reduction of metal salt solutions such as nitrate or perchlorate. This simple one-step preparation can be adapted as a soft chemical route to the preparation of thin films of hydroxides.