Las propiedades de los yesos de moldeo y enlucidos y sus ensayos
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Informe sobre los elementos prefabricados de yeso utilizados hoy día en Francia
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El empleo del yeso en Gran Bretaña
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Bibliography
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Dependence of the Superconducting Transition Temperature on Carrier Concentration in Semiconducting SrTiO3
Received 21 January 1965DOI:https://doi.org/10.1103/PhysRevLett.14.305©1965 American Physical Society
Some Transport Properties of Oxygen-Deficient Single-Crystal Potassium Tantalate (KTaO3)
Hall-effect and electrical-conductivity measurements have been made on reduced single crystals of the perovskite potassium tantalate (KTa${\mathrm{O}}_{3}$) over the temperature range 1.6-295\ifmmode^\circ\else\textdegree\fi{}K. Lattice scattering predominates above 100\ifmmode^\circ\else\textdegree\fi{}K where the Ha…
Studies on Orthoferrites at the Weizmann Institute of Science
The Curie point, lattice constants, sublattice magnetization, spontaneous magnetic moment, susceptibility, and the nonlinear susceptibility have been measured on the compounds RFeO3 with R yttrium or a rare earth. The main conclusions from these measurements are: (1) The rare-earth ions contribution to the magnetic pr…
α-D-Glucose: Precise Determination of Crystal and Molecular Structure by Neutron-Diffraction Analysis
This analysis provides the first precise crystal and molecular structural parameters for α-D-glucose. The C—C, C—H, and O—H bond lengths deviate only slightly from their means of 1.523 Å, 1.098 Å, and 0.968 Å. The C(1)—O(1) bond length, 1.389 Å, is significantly shorter than the mean value, 1.420 Å, of the other C—O b…
Chemical Background of Silicones
The silicones are in most cases relatively complex mixtures rather than pure molecular species. Their structures and chemical properties can be controlled, however, with sufficient reproducibility to give compositions with unique characteristics. The organic groups serve not only as a device for controlling the siloxa…
Diffusion of Boron in Graphite
The mobility of substitutional boron in single crystals of graphite has been measured by an etch-decoration method, which makes it possible to locate individual boron atoms by electron microscopy. The mobility of boron is not very sensitive to the boron concentration, for B/C values between 10−2 and 10−8. The diffusio…
Properties of Group VI B Elements Under Pressure. I. Melting Curves of S, Se, and Te
The melting curves of S, Se, and Te have been determined to 45 kbar by differential thermal-conductivity analysis in a tetrahedral anvil apparatus. The data for sulfur show that the melting point increases approximately linearly from 114\ifmmode^\circ\else\textdegree\fi{}C at atmospheric pressure to about 700\ifmmode^…
Normal Vibrations of the Polymer Molecules of Helical Conformation. V. Isotactic Polypropylene and Its Deuteroderivatives
Polarized infrared spectra of isotactic polypropylene (IPP),[Complex chemical formula]were measured in the region from 4000 to 80 cm−1. The normal vibrations of these three polymers were calculated for the infrared- and Raman-active A and E species, by the use of the GF-matrix method with the Urey—Bradley force field.…
Relation between Absorption and Emission in the Region of theRLines of Ruby
We have measured the radiative efficiency (ratio of $R$-line photons to the total number of photons emitted) and absorption cross sections for the $R$ lines of dilute ruby, as a function of polarization and temperature between 20 and 373\ifmmode^\circ\else\textdegree\fi{}K. We have also measured the fluorescent lifeti…
Symmetry Considerations on Martensitic Transformations: "Ferroelectric" Metals?
Received 22 December 1964DOI:https://doi.org/10.1103/PhysRevLett.14.217©1965 American Physical Society
Pressure Dependence of the Alpha-Beta Transition Temperature in Silver Selenide
The pressure dependence of the alpha-beta transition temperature in Ag(2)Se was determined by observing the temperature at which the sharp change in resistivity occurs when Ag(2)Se is transformed from the low-temperature orthorhombic to the high temperature body-centered-cubic form. The transition temperature increase…
Screw Dislocations in Graphite
Graphite contains varying concentrations of screw dislocations whose Burgers vector parallels the c axis. Single crystals of natural graphite contain very few such dislocations; furthermore, their Burgers vector always exceeds 450 angstroms. Pyrolytic graphites annealed above 3000 degrees C contain abundant screw disl…
Anisotropy of thermal conductance in near-ideal graphite
Abstract Measurements of thermal conductivities of a number of pyrolytic graphites are reported including values for annealed, hot pressed graphite (IFPA 57). Thermal conductivities of IFPA 57 in both basal plane and c-axis directions approach the values for ideal graphite at higher temperatures. A theoretical estim…
Gespannte polycyclische Systeme aus Drei‐ und Vierring‐Bausteinen
Abstract Aus kleinen Ringen aufgebaute Polycyclen sind seit einigen Jahren bekannt. Ihre auch theoretisch interessanten chemischen und physikalischen Eigenschaften werden erläutert und Darstellungsmethoden an einigen Beispielen gezeigt. Besonders besprochen werden die Kohlenstoff‐Gerüste wie sie das Tetraeder, das Dew…
Potassium Content of Illite
The average potassium oxide content of 18 Paleozoic two-layer monoclinic illites is 8.75 percent. There is an excellent linear relation between the ratio of the intensities of the reflections at 10 angstroms and 5 angstroms (10 A/5 A) and the potassium oxide content. The frequency distribution curve of the 10 A/5 A in…
Optical Second-Harmonic Generation in Crystalline Amino Acids
Optically active amino acids contain many highly efficient optical second-harmonic generators. When light from a ruby laser at 6943 A falls on the crystalline amino acids with sufficient intensity, the second harmonic of the light at 3471 A can be observed. Although the symmetry requirements for optical second-harmoni…