Investigation on the strength of construction concrete
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Investigation on the meteorization of cements by infra-red spectroscopy
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Present state of research on concrete additives in Spain (lETcc)
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What an engineer ought to know on the nature of additives
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New method for the design calculation of rotary cement kilns
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Bibliography
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Diimide reduction of porphyrins
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDiimide reduction of porphyrinsHoward W. Whitlock Jr., R. Hanauer, M. Y. Oester, and B. K. BowerCite this: J. Am. Chem. Soc. 1969, 91, 26, 7485–7489Publication Date (Print):December 1, 1969Publication History Published online1 May 2002Published inissue 1 December 1969https:/…
Kinetic analysis of thermogravimetric data
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetic analysis of thermogravimetric dataJohn Henry. Sharp and Sally A. WentworthCite this: Anal. Chem. 1969, 41, 14, 2060–2062Publication Date (Print):December 1, 1969Publication History Published online1 May 2002Published inissue 1 December 1969https://pubs.acs.org/doi/10…
Investigations of dislocation strain fields using weak beams
A method for determining the position of dislocation lines accurately from dislocation images is reported and applied to the case of measuring the separation of partial dislocations. A theoretical analysis of the method is given, and the predictions verified by many-beam computed image profiles. The separation of part…
Metallkomplexe von Porphyrinen
Abstract Die Darstellung einer Reihe von Porphyrin‐Metall‐Komplexen wird beschrieben. Unter Berücksichtigung von bekanntem und neuem Tatsachenmaterial wird eine Deutung der unterschiedlichen Elektronenspektren der Porphyrinkomplexe gegeben. Ausgehend von Salzen ms ‐tetrasubstituierter Porphine, die als Alloporphin‐Der…
Evidence of Voids Within the As-Deposited Structure of Glassy Silicon
We present electron diffraction data from amorphous silicon which cannot be reconciled with the intensity profiles derived from small-crystallite models based on the diamond structure. Our diffraction patterns do reveal a pronounced low-angle scattering which anneals out on progressive heating and is indicative of act…
Optical Dispersion and the Structure of Solids
A new energy parameter ${\mathcal{E}}_{d}$ is introduced to describe dispersion of the electronic dielectric constant. This dispersion energy is found to obey an extraordinarily simple empirical relation in the more than 50 ionic and covalent crystals for which reliable refractive-index dispersion data are available.…
Magnetic-Field Effects on a Compensated Cholesteric Liquid Crystal
By measuring changes in the dielectric constant of a 1.75:1 cholesteryl chloride–cholesteryl myristate (CM) mixture in the presence of magnetic fields H up to 10 kG, the orientation of the molecular and helical axes with respect to the field direction can be deduced, and the possibility of a dependence of the alignmen…
A low temperature phase of (NH4)2TeBr6
X-Ray diffraction has shown the existence of a low temperature tetragonal phase of (NH 4 ) 2 TeBr 6 having space group P4/mnc(D 4h 6 ) with a = 7.501, c = 10.765 Å.
Electronic Structure of Luminescence Centers of ZnS Phosphors Activated with Impurity Ions of s2 Configuration. II. ZnS:Pb (Zinc-Blende) Phosphors
A, B , and C bands with peaks at about 4910, 4220, and 3990 Å (mean values for split subbands at 77°K), respectively, were found in the excitation or reflection spectra of visible region of ZnS:Pb (zinc-blende) phosphors. These bands were analyzed by means of Sugano's molecular-orbital theory and identified unambiguou…
Quasiequilibrium Treatment of Gas–Solid Reactions. I. Evaporation Rates of Volatile Species Formed in the Reaction of O2 with W, Mo, and C
A quasiequilibrium treatment of heterogeneous reactions is used to compute the rates of evaporation (desorption) of volatile species formed in the reaction of gaseous O2 with solid tungsten, molybdenum, and graphite under conditions of low pressure and high temperature. The results are compared with existing mass–spec…
Theory of a Structural Phase Transition in Perovskite-Type Crystals
Structural phase transitions in perovskite crystals involving displacements of the oxygen octahedra due to the condensation of linear combinations of the triply degenerate ${\ensuremath{\Gamma}}_{25}$ modes at the $R$ corner of the Brillouin zone are discussed with the help of a model Hamiltonian. These distortions ar…
Vaporization of Uranium Mononitride and Heat of Sublimation of Uranium
The vaporization of uranium mononitride UN has been investigated by the Knudsen effusion technique in combination with a mass spectrometer. The vaporization occurs incongruently by preferential loss of nitrogen forming the two-phase system nitrogen-saturated liquid uranium–uranium-saturated nonstoichiometric uranium m…
Matrix Isolation Studies of Group-IV Oxides. I. Infrared Spectra and Structures of SiO, Si2O2, and Si3O3
The matrix isolation of silicon monoxide vapor leads to the formation of at least three distinct species: SiO, Si2O2, and Si3O3. Infrared absorptions for these molecules are observed at 1223.9 cm−1 (Si16O); 804.7, 766.3 cm−1 (Si216O2); 972.6, 631.5, 312.0 cm−1 (Si316O3). Equations are given for the in-plane vibrations…
Generalized X-Ray Scattering Factors
Generalized x-ray scattering factors have been determined from the evaluation of Fourier transforms of atomic-orbital products. Self-consistent-field atomic orbitals for first-row atoms have been studied. Analytical scattering expressions for rapid evaluation on digital computers have been developed. Scattering factor…