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Evocación

Introducción

Enlucidos y revestimientos en la lucha contra los incendios (El yeso)

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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…