Materials Literature
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Thermal denaturation temperature of newly reconstituted collagen fibrils from rat tail tendons is 52 degrees C compared with 42 degrees C for neutral solutions. This suggests that the increase in concentration of collagen within the fibril increases the stability of the individual molecules. The absence of firm interm…
CONTENTS 1. Magnetic Properties of Rare-earth Ferromagnets 179 2. Neutron-Diffraction Studies of the Magnetic Structure of Rare-earth Ferromagnets 183 3. Theory of the Helicoidal Magnetic Structure 184 4. Nature of Magnetic Phase Transitions in Rare-earth Ferromagnets 190 5. Antiferromagnetism of Metals of the Cerium…
Abstract The morphology of thin films of natural rubber crystallized under unidirectional strain has been examined in the electron microscope. As strain increases the spherulitic morphology of unstrained films gives way gradually to a fibrillar morphology with crystalline filaments (α filaments) measuring 60 by 250 Å,…
The energy levels of an impurity ion in a solid are in general shifted and broadened by thermal vibrations of the host lattice. A study of these effects in a simple system can lead to some understanding of the phonon-impurity interaction. This paper reports measurements of the width and positions of the sharp fluoresc…
Considering the specific heat, the magnetic susceptibility, and the crystal structure of Cu${(\mathrm{N}{\mathrm{H}}_{3})}_{4}$S${\mathrm{O}}_{4}$\ifmmode\cdot\else\textperiodcentered\fi{}${\mathrm{H}}_{2}$O, we conclude that this substance has the magnetic linear chain property. The ratio of the exchange integrals $|…
The Percus-Yevick approximate equation for the radial distribution function of a fluid is generalized to an $m$-component mixture. This approximation which can be formulated by the method of functional Taylor expansion, consists in setting $\mathrm{exp}[\ensuremath{-}\ensuremath{\beta}{\ensuremath{\phi}}_{\mathrm{ij}}…
The dielectric constant and dissipation factor of β- and α-Ta2O5 ceramics and of plates cut from a boule of α-Ta2O5 have been measured from 77° to 373° K over a frequency range from 100 cps to 100 kc/sec. β-Ta2O5 ceramics behave as typical dielectric materials. On the other hand, α-Ta2O5 ceramics exhibit large migrati…
Abstract The optical transmission spectra of several diamonds have been studied over the range 5·0 to 6·0 eV (2450 to 2000 Å) and at many temperatures between 90 and 600 °K. The reflexion spectrum was also recorded between 5 and 14 eV (2450 to 900 Å) at 295 °K and between 5 and 8 eV (2450 to 1550 Å) at 133 °K. The int…
The X-ray powder diffraction data on A1PO 4 have been obtained on a diffraetometer. The system is found to be trigonal with cell constants a =4.941 /~, c = 10.95 /~ and space group P3121. From the known similarity between ALP04 and s.quartz, the atomic coordinates have been determined to be O(1): x = 0.275, y = 0.406,…
The sodium cobalt molybdate studied here crystallizes in space group D16-Pnma of the orthorhombic system in a cell of dimensions a = 5.25, b = 10.78, 2h c 18.02 A.
Abstract The crystalline forms of several isotactic unbranched polyolefins in the series polyhexene‐1 to polyoctadecene‐1 have been investigated by X‐rays. Polytetra‐, ‐hexa‐, and ‐octadecene‐1 each crystallise three‐dimensionally in two forms, Types I and II. Both types give characteristic diffraction patterns and al…
The electric-field gradient tensor at the iron nucleus in ferrous (${\mathrm{Fe}}^{2+}$) compounds is investigated. One sees that under the combined action of axial and rhombic crystalline fields and the spin-orbit interaction, the ferrous-ion $(^{5}D,3{d}^{6}){d}_{\ensuremath{\epsilon}}$ states produce a large, tempe…
Abstract Ein sehr stabiler farbloser Kohlenwasserstoff, genannt Fulminen, wurde aus den höchstsiedenden Anteilen des Steinkohlenteers isoliert. Seine wahrscheinliche Konstitution ist die des 1.2‐Benzo‐picens (I).
Abstract Some preparations of xylan in the form of transparent membrance or amorphous powder prepared from deciduous woods such as beech and birch show a number of Debye‐Scherrer rings at the irradiation with x‐ray. Of special interest from the crystallographic standpoint is the diffraction pattern of the membrane, wh…
Abstract Pyrophyllite gives a diffraction pattern consisting of sharp and diffuse reflections. The unit cell for all the reflections is monoclinic with a = 5.17 Å, b = 8.92 Å, c = 18.66 Å, β = 99.8°. From the absences, the space group is either C 2/ c or Cc but there are additional absences of hkl reflections with k ≠…
The changes in the x-ray Debye–Scherrer diffraction pattern, as a function of plastic strain, have been measured for a silicon bronze (Cu–6·6 at. % Si–1·2 at. % Mn) tensile specimen. Analysis of line positions and line breadths gave the following results. The stacking-fault probability increased with extension, and ne…
The thermal conductivity K of high-purity platinum appears to be a reproducible quantity for temperatures between 75°K and the melting point at 2047°K. This behavior combined with the outstanding chemical and physical properties of platinum suggests that platinum could serve as a useful K standard in this region. From…
The polarized crystal spectrum of tetrakis-thoiurea-nickel chloride has been determined. The molecular symmetry is C4v; however, the results indicate that the absorptions arise from a field of lower symmetry, since in C4v symmetry the observed ``parallel'' absorptions would be orbitally forbidden. The intensity of the…
The ternary system U‐C‐O was investigated and a diagram is given expressing the phase relations in specimens which were reacted at 1800°C in vacuum or in inert atmospheres and furnace cooled. A U(C,O) single‐phase area exists in this diagram. The limit of substitutional solid solution of oxygen atoms for carbon atoms…
Anodic and cathodic polarizations of nickel have been studied using a galvanostatic technique with low current densities and an atmosphere of hydrogen. Polarization experiments have been conducted using 0.1 N sodium hydroxide, 1 N sodium carbonate and 0.1 N sodium borate solutions. It has been shown that passivation i…