Materials Literature
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Abstract Proton NMR. spectra of purine, adenine, guanine and methylsubstituted guanines have been measured in CF 3 COOH, FSO 3 H and FSO 3 HSbF 5 SO 2 at 27° and low temperatures. These conditions permit to study multiple protonation of purines, using chemical shifts of CH, NH and OH protons. The spectra of mono‐, d…
Measurements of the heat capacity, thermal expansion, and thermal conductivity on synthetic crystals of undoped and neodymium-doped fluorapatite are reported. Fitting the low-temperature specific heat data to a Debye model yields a Debye temperature of 550°K. At 25°C the thermal expansion coefficients are 10.0×10−6 °K…
Measurements of thermal expansion and Young’s modulus at −150°∼500°C have been carried out with single crystal specimen, 3 mm in diameter and 12 cm long, of 18–12 type stainless steel. At the same time the rigidity modulus of a polycrystal specimen was measured at room temperature. At 20°C the Young’s moduli determine…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structures of americium trichloride hexahydrate and berkelium trichloride hexahydrateJohn H. Burns and Joseph Richard PetersonCite this: Inorg. Chem. 1971, 10, 1, 147–151Publication Date (Print):January 1, 1971Publication History Published online1 May 2002Published i…
The influence of chloride and sulfate ions on the corrosion of iron in H 2 SO 4 media at p H near 3 was studied. It was shown that both ions could be either aggressive or not aggressive under definite conditions. Chloride ions accelerate corrosion considerably when the anodic reaction contributes significantly to the…
The crystal structure of 8,12-diethyl-2,3,7,13,17,18-hexamethylcorrole has been elucidated by X-ray crystallographic analysis and the geometry of the macrocyclic ring system has been found to be not strictly planar. The distortions are probably caused by short N–N contacts brought on by the direct C(1)–C(19) link. The…
This review is concerned with the structure and resultant electrical conduction properties of three types of film, defined as metallic, dielectric and discontinuous metallic; it is shown that the behaviour of the last one can be discussed as extensions of the first two. The review commences with a brief discussion of…
Abstract Viscosity and pH of aqueous borate–poly(vinyl alcohol) mixtures were determined under different conditions toward a clarification of the thickening mechanism. Boric acid has little effect on dilute poly(vinyl alcohol) (PVOH), but sodium borate causes sharp viscosity increases which are temperature sensitive a…
Dimethylsilanone, Me2Si : O, is postulated as an intermediate in the gas-phase thermalde composition of octamethylcyclotetrasiloxane; a lower limit for the silicon–oxygen π-bond strength in dimethylsilanone is calculated.
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Abstract Positive charges in acid soils reduce CEC at low electrolyte concentration probably by double layer interaction. The resultant net ECE (determined by washing soil free of salt with water) is the effective CEC under field conditions and the difference between net CEC and exchangeable bases is accordingly a con…
The preparation of a representative series of lead thiolates, Pb(SR)2(R = Et, Bun, But, Ph, p-C6H4Me, o-C6H4Me, p-C6H4Cl), is reported. Thermal decomposition of these thiolates leads to the formation of lead sulphide and the organic sulphide, R2S. Reaction of the thiolates with sulphur (or selenium) gives lead sulphid…
The thermal conductivities, λ, of single‐crystal and polycrystalline UO 2 were measured from 80° to 420°K. The results indicate no observable difference in λ between single‐crystal and polycrystalline UO 2 , and both materials have broad peaks in λ at ∼220°K. The results were used with literature values to determine t…
The thermal decomposition of lithium oxalate has been studied by means of weight loss and measurement of surface area. It has been found possible to correlate changes in surface area with the kinetics of decomposition.The reaction studied was the decomposition of the oxalate to the carbonate which occurs with an incre…
The thermal decomposition of KMnO4 in the temperature range 25–900° in air and nitrogen has been studied by thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction, and chemical analysis. The idealised decomposition equation (250°, air) was found to be 10 KMnO4→ 2·65 K2MnO4+(2·35 K2O,7…
Pentaco-ordinate complexes of the type M(pnp)X2 or M(pnp)XY are described; M = FeII, CoII, or NiII; X = Cl, Br, or I; Y = NCS; pnp is the new ligand 2,6-bis-(2-diphenylphosphinoethyl)pyridine. Distorted trigonalbipyramidal structures are assigned on the basis of physical properties. Magnetic susceptibility measurement…
Abstract Depending on temperature and load rate an unoriented polymer solid under sufficiently large applied stress either deforms plastically (high temperature, low rate of loading) or undergoes brittle fracture (low temperature, high rate of loading). The fracture proceeds through the areas of minimum strength, i.e.…
A moderate surface reduction of TiO2(anatase or rutile) at 573–773 K under vacuum, or in the presence of carbon monoxide or hydrogen, or finally at room temperature under ultra-violet irradiation in vacuum or in the presence of hydrocarbons, creates two types of paramagnetic centres, which are identified by e.s.r. spe…
In order to cOlltrol the cast structllre, it is most im/Jortallt to kllow lite Jorlllatiol!mechanism and the behavior oj eqlliaxed crystals ill tlte 1II0ltell metal durillg the solidification .The solidification jJhenomellol!was directly observed with (III o/Jtical microscojJe Jor the cases q! 99.999° oSn, Sn -O.l, 0.…
Arago nit e (C aCO ,,) c ry s ta lli zes in th e unit ce ll a = 4.9598(5) /\ . 6 = 7.9641(9) A, and c = 5.7379(6) A at 25 C with four form ula we ight s in s pace-g roup Pm cn. Th e s tru cture has bee n re fin ed to N".= 0.024 . N = 0.040 using 765 x-ray re Aec tion s fro m a sin gJe c rysta l. Th e Ca ion is coo rdi…