ÉTUDE DES NIVEAUX DE220Fr,219Fr,216At ET215At
Résultats de spectrométrie α pour 224Ac 27 raies, 223Ac 25 raies, 220Fr 15 raies, 219Fr 6 raies.
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Une nouvelle espèce minérale : l'afghanite de Sar-e-Sang, Badakhshan, Afghanistan. Comparaison avec les minéraux de groupe de la cancrinite
L'afghanite, nouvel alumino˗silicate de sodium, calcium et potassium, a été découverte dans la mine de lapis-lazuli de Sar-e-Sang, Badakhshan, Afghanistan. Hexagonale avec a = 12,77, c = 21,35 Å, V = 3015 ų, les groupes de symétrie possible étant P6₃/mmc, P6₃mc ou P[-6]2c. Z = 3 (Na,Ca,K)₁₂ (Si, Al)₁₆ O₃₄ (Cl, SO₄, C…
Electrochemical reactions. Part V. The formation of cyclic glycols in the reduction of aromatic diketones
The electroreduction of 1,8-diaroylnaphthalenes, 2,2′-diaroylbiphenyls, and αω-diaroyl-propanes, -butanes, and -pentanes with 4-hydroxy- and 4-methoxy-substituents on the aryl group has been examined. Cyclic glycols are formed, together with other products, except in the case of the αω-diaroylpentanes which give linea…
Fused Salt Electrolysis of Titanium Metal from Ti-C-O Alloys or TiC
Pure titanium metal was electrodeposited on a cathode by double fused salt electrolysis with the cell designed specifically for this work. Electrolysis was carried out in NaCl, NaCl-TiCl2-TiCl3 and NaCl-K2TiFx baths. The anode materials for the first stage electrolysis were Ti-C-O alloys or TiC prepared by carbon redu…
Atmospheric Corrosion of Carbon and Low Alloy Cast Steels
Nine carbon and low alloy cast steels cast in panel form, some machined and others unmachined, were exposed in marine and industrial atmospheres for periods of one-, three-, seven-, and 12-years and recorded as to weight loss information. The weight loss was converted to corrosion rate in terms of inches penetration p…
The dependence of the spherical aberration coefficient of an electron-optical objective lens on object position and magnification
The dependence of the spherical aberration coefficient C s on object position z 0 and magnification M is studied using Glaser's bell-shaped field model. It is shown that C s may be written in the forms IMG1 where a i and b i are functions of the lens excitation k 2 . a i and b i are tabulated for a range of values of…
Stress Relaxation in Single Crystals of Copper and α-Brasses
Stress relaxation at constant strains has been studied in crystals of copper and α-brasses containing 10, 20, or 30 at.-% zinc at 77,200, and 291° K after consecutive small plastic deformations. Close to the yield point the relaxation was generally within 1% of the applied stress, but at large deformations, notably wi…
Further percentage points for WN2
Distributional results in the lower tail, and further percentage points in both tails, are given for the statistic WN2, or NωN2, used in testing for goodness of fit.
Étude structurale des hydroxystannates CaSn(OH)6 et ZnSn(OH)6 par diffraction neutronique, absorption infrarouge et résonance magnétique nucléaire
The complete structure of cubic hydroxystannates, CaSn (OH)₆ and ZnSn(OH)₆, of space group Pn₃, has been determined by neutron diffraction at 4° K (powder techniques), and with the study of the spectrum of CaSn (OD)₅,₄₅ (OH)₀,₅₅. The 24 hydrogen atoms of the unit cell form two sorts of hydrogen bonds with double well-…
The synthesis of β-amyrin
18α-Olean-12-ene, which is in acid-catalysed equilibrium with olean-13(18)-ene (δ-amyrene), has been converted in several steps into olean-12-ene (β-amyrene). Transformation of this hydrocarbon into its 11α-hydroxyderivative and photolysis of the nitrite of the latter gave 11α-hydroxy-1-oximino-olean-12-ene. This oxim…
Carpet Performance Evaluation
Thirty two tufted carpets, representing variations in fiber content, pile weight, and cut and loop-pile construction were studied for stress-strain behavior under cyclic loading to 12 lb/in. 2 on an Instron tensile tester. Results are presented conventionally in terms of compression, recovery, matting, and resilience.…
Relationship between stereostructure of poly(vinyl alcohol) and its acetalization reaction
Abstract By measurement of peak areas in the dioxymethylene region of high‐resolution NMR spectra of partly formalized poly(vinyl alcohol), PVA, the relationship between tacticity of PVA, rate of formalization reaction, and stereochemical configuration of poly(vinyl formal) was studied. Formation of cis ‐formal at an…
Optical Energy Gap in TlSe
Abstract The results of a study to characterize samples of single crystals of TlSe grown by the Bridgman‐Stockbarger and zone recrystallization techniques are given. The X‐ray diffraction patterns were indexed as a tetragonal lattice whose parameters were a = 8.02 Å and c = 7.00 Å. The absorption and transmission meas…
Base-catalyzed decomposition of peroxypivalic acid in aqueous solution
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBase-catalyzed decomposition of peroxypivalic acid in aqueous solutionEdward Koubek and J. E. WelschCite this: J. Org. Chem. 1968, 33, 1, 445–446Publication Date (Print):January 1, 1968Publication History Published online1 May 2002Published inissue 1 January 1968https://pubs…
Sr[sub 3](PO[sub 4])[sub 2]-Tb, A Bluish-White Emitting Cathode-Ray Phosphor with a Long Decay Time
Abstract not Available.
The Cathodoluminescence Spectra and Coordination of Mn2+, Fe3+, and Cr3+ in βLiAl[sub 5]O[sub 8]
Abstract not Available.
A Kinetic Study on Deoxidation of Steel
Single and coop erative deoxidations with Mn , Si, and Al are /Jractised in iron baths melted by high-frequency Jurnace and T ammann Jurnace. K inetics oj deoxidation -jnocess are analysed to evaluate the sel){lration-rate oj p rimary inclusions. T he results oj experiments are summarized as Jo llows :
THERMAL TRANSITION OF LEUCITE
The thermal transition of leucite was studied. The specimens were from Nyiragongo, the Congo and from Vesuvius, Italy, and X-ray powder and single crystal diffraction experiments were carried out from room temperature up to 800°C. At room temperature, the crystal, single and cubic in appearance, is composed of six she…
Thermal rearrangement of diphenyl carbonate
The thermal degradation of diphenyl carbonate has been examined in the gas and condensed phases. From a detailed analysis of the products it is suggested that the mechanism involves an initial rearrangement to 2-phenoxy benzoic acid followed by several competing reactions of the acid. The effect of phase is discussed.…
Infra-red study of adsorption and oxidation of ammonia on silica-supported platinum and silica
An infra-red study of the adsorption of ammonia on silica-supported platinum in the region 3600-1900 cm–1 over a temperature range 25–130°C yields four spectral features: a strong broad absorption at 2960 cm–1 due to the perturbed ν(OH ···) in a surface SiOH ··· NH3 complex, a shoulder at 3280 cm–1 and two fairly shar…