Materials Literature
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Abstract Volatile products present in poly(vinyl chloride), PVC, after outdoor weathering have been compared with volatiles from laboratory, UV exposed PVC surfaces. Compounds both present in the photo‐degraded polymer surface layer and directly emitted from the polymer were measured in the laboratory experiments. The…
The efficient conversion of light energy into chemical energy is essential if solar energy is to be utilized successfully. The mechanisms of photosynthesis in green plants are used as guiding principles to propose different types of electron and proton transporting systems, for example, a chemical system based on poly…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFacile and Remarkably Selective Substitution Reactions Involving Framework Silicon Atoms in Silsesquioxane FrameworksFrank J. Feher, Shawn H. Phillips, and Joseph W. ZillerView Author Information Department of Chemistry, University of California Irvine, California 9269…
Zirconia‐based ceramics are considered as support materials for superconducting magnets, and the relationship between composition and mechanical properties at cryogenic temperature is reported. Ce‐TZP materials with CeO 2 content between 14.5 and 16.5 mol% can be made with high strength (600 MPa) and high toughness (1…
Surface enhanced Raman spectroscopy was used to study species present on carbon steel in CO 2 and N 2 saturated brines at 24 and 65°C. In the presence of CO 2 , a surface carbonate species, characterized by a peak at 1078 cm − 1 , was observed on the cathodically polarized steel surface. In CO 2 ‐saturated solutions,…
Stainless steel couplings in the main cooling water pipes of HVDC thyristor valves have been in use since 1983, with overall satisfactory behavior. However, some water leakage due to corrosion below the sealing O-rings of the couplings was observed during 1992. An extensive investigation and follow-up worldwide showed…
This paper deals with the hydrothermal modification of the physicochemical properties of complex mineral sorbents and catalysts. The hydrothermal modification of alumina, magnesia, ferric oxide and zirconia/silica hydro- and xero-gels as well as other complex adsorbents obtained by the coprecipitation and mechanical s…
Two aliphatic series of polyimides having well-defined structures with inherent viscosities of 0.4−2.7 dL g -1 were readily synthesized by the solid-state thermal polycondensation under high pressure of the salt monomers composed of aliphatic diamines having 6−12 methylene units and both pyromellitic acid (PMA) and bi…
The relationship between coatings, cathodic protection (CP), and external corrosion of underground pipelines is described. Historically, this problem has been addressed by focusing on the corrosion and CP processes associated with holidays, e.g., coating disbondment and CP current flow within the disbonded region. The…
The crystal structure of desheptapeptide (B24-B30) insulin (DHPI), a virtually inactive analog of insulin, was determined at 1.6 A resolution. In the refined structure model, DHPI retains three alpha-helices (A1-A8, A12-A18, and B9-B19) as its structural framework, while great conformational changes occur in the N and…
Inclined homeotropic alignment was realized by irradiation of unpolarized ultraviolet light on a polyimide film that originally exhibited homeotropic alignment. Unpolarized UV light was irradiated from an oblique direction (45-degree inclined angle) once. The liquid crystal cell with a pair of inclined homeotropic ali…
Ozone adsorption on CaO pretreated at different temperatures was studied by FTIR spectroscopy at 77−300 K. Besides physisorption effects, a weak complex was observed formed by ozone molecules with the OH surface groups, which have pronounced basic properties, as shown by a downward shift of the ν OH band by about 21 c…
Compounds in the Sr1−xBaxZrSe3series, where 0≤x≤0.68, were prepared from SrSe, BaSe, Zr, and Se in evacuated and sealed silica ampules, at temperatures between 900 and 950°C. An amorphous Zr–Se phase is competitively formed in the reaction thus synthesis mixtures require 20 and 40% mole excess of Zr and Se, respective…
Conditions to remove contaminations adsorbed on a surface in wet cleaning processes have to be perfectly controlled. Megasonic excitation of ozonized water removes hydrocarbon contamination from silicon surfaces. When ozonized water was excited by megasonics at a frequency of about 1 MHz, OH radicals were produced in…
By a mixed condensation of 1,3-bis(3″,4″-dicyanophenoxy)-2-ethyl-2-methylpropane with a large amount of 4,5-bis(3,3-dimethyl-1-butynyl)phthalonitrile, 1,3-bis-2″-(9″,10″,16″,17″,23″,24″-hexakis(3″,3″-dimethyl-1″-butynyl)phthalocyaninoxyl)-2-ethyl-2-methylpropane, was synthesized as a binuclear phthalocyanine having a…
Mangano(II)undecatungstosilicate [(H2O)MnSiW11O39]6− was studied by cyclic voltammetry in aqueous solution at various pH values. The pH-dependent wave patterns are influenced by additional processes and were further investigated by variation of scan rates, substance concentration and buffer concentration, focussing on…
The Knudsen effusion mass spectrometric method has been used to measure the equilibrium partial pressures of SiC 2, Si 2 C, Si 2 C 2, and Si 3 C above the SiC−graphite system at temperatures between 1750 and 2000 K. New thermal functions have been calculated for these molecules from recent literature experimental and…
Viewing angle characteristics were systematically obtained when using in-plane switching (IPS) of liquid crystals. Although the IPS mode originally shows stable electro-optical performance regardless of viewing directions, the viewing angle characteristics are found to be strongly dependent on pretilt angle (slant ang…
The origin of the ferroelectric materials LiNbO3 and LiTaO3 was studied using extensive LAPW calculations. The coupled displacements of the oxygens and lithiums give a deep double well whereas oxygen alone displacements result in a shallower double well as a result of the oxygen-lithium overlap. Density of states calc…
Amino-functionalized poly(arylene ether ketone)s have been synthesized by nucleophilic aromatic substitution from isomeric amino-functionalized monomers and Bisphenol A. The polymerizations have been found to proceed without any side reactions. The polymers were characterized by IR, 1 H NMR, and 13 C NMR spectroscopy…