All issues
Successor
Volume 32 (1980)
- Issue 12 Pages 721-
- Issue 11 Pages 671-
- Issue 10 Pages 585-
- Issue 9 Pages 507-
- Issue 8 Pages 431-
- Issue 7 Pages 365-
- Issue 6 Pages 309-
- Issue 5 Pages 265-
- Issue 4 Pages 181-
- Issue 3 Pages 129-
- Issue 2 Pages 67-
- Issue 1 Pages 1-
- Issue Supplement3 Pag･･･
- Issue Supplement2 Pag･･･
- Issue Supplement1 Pag･･･
Volume 20 (1968)
- Issue 4 Pages 289-
- Issue 3 Pages 115-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 20, Issue 2
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tsuneji RIKITAKE, Yukio HAGIWARA1968 Volume 20 Issue 2 Pages 57-65
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSGrowth of a magnetic field given to the zero-field state of a Bullard-Gellman dynamo model is studied. Reaction of electromagnetic origin to the fluid motion is completely ignored. A steady state seems to be reached within a time comparable with that of free decay of the magnetic field, say several thousand years, for the earth's core. A more complete study, in which an equation of motion is taken into account, will be made in the second paper.View full abstractDownload PDF (691K) -
E. J. SCHWARZ1968 Volume 20 Issue 2 Pages 67-74
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSThe results of the thermomagnetic investigation of two natural pyrrhotites of intermediate chemical composition indicate the co-existence of (1) a ferrimagnetic phase of estimated composition Fe0.875S to Fe0.88S (Tc≈300°C) and (2) an antiferromagnetic phase which becomes ferrimagnetic above 180°C due to. vacancy ordering (Tc between 250 and 275°C). The second phase comprises 70 to 90% of the individual specimens, and is less Fe deficient than the composition of the whole samples. These conclusions were largely confirmed by the results of the application of magnetite powder to etched polished surfaces of the samples. Changes in thermomagnetic properties of both phases are observed after continued heating of the specimens above about 250°C. Heating of the specimens to 500-600°C probably results in homogenization of the specimens as the points of inflection below 300°C on the J(T) curves disappear.View full abstractDownload PDF (3115K) -
Change in the initial susceptibility of fine grain assemblage of ferromagnetics due to uniaxial compressionHajimu KINOSHITA1968 Volume 20 Issue 2 Pages 75-83
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSA simple model for calculating the change in the initial susceptibility of fine grain assemblages of ferromagnets under uniaxial compression is presented. The change in the initial susceptibility under compression is explained by combining two; homogeneous rotation of the spontaneous magnetization vector of individual magnetic domains and hardening of the domain wall movement due to deformation of materials under uniaxial compressional stress. Numerical calculation is shown to be in agreement with the experimental values of natural titanomagnetite and nickel.View full abstractDownload PDF (818K) -
Kita-Matsuura basalt, Kyushu, JapanM. OZIMA, I. KANEOKA, M. KONG, H. KINOSHITA, K. KOBAYASHI, N. OHNAKA, ...1968 Volume 20 Issue 2 Pages 85-92
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSPaleomagnetism and K-Ar ages of two successive lava flows from Kita-Matsuura, northwestern Kyushu were studied in attempting to estimate the time required for the geomagnetic field to switch from one polarity to the other. Both lava flow successions record normal and reversed polarities. K-Ar ages of these flows range from 7m. y. to 10m. y. However, because of inconsistensies within a flow and among successive flows, K-Ar ages should be regarded as indicating approximate ages of these lava flows. Hence, it was not possible to determine the transition time for the geomagnetic field switching.View full abstractDownload PDF (749K) -
Mitiyasu OHNAKA, Hajimu KINOSHITA1968 Volume 20 Issue 2 Pages 93-99
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSExperiments to test the effect of directional stress on the remanent magnetization of magnetite bearing rocks and nickel polycrystallites are described. The TRM of volcanic rocks under repeated compression of less than 1kb was found to reveal a nearly reversible change in intensity. The intensity increases when the direction of compression is perpendicular to that of TRM and decreases when the compression is parallel, in accordance with the theory of magnetoelasticity. Stability of IRM and PRM induced in previously workhardened nickel rods under compression is compared with that of TRM. TRM of a nickel polycrystallite under compression changes in a manner similar to that of volcanic rocks. However, no reversible change was found for IRM, even the compressional stress did not exceed a few hundred bars. The results, combined with the magnetic susceptibility of rocks under compression, can be used for estimation of seismo-magnetic effects.View full abstractDownload PDF (814K) -
Hanamagari and Kirizumi andesites, Gumma Prefecture, JapanMinoru OZIMA, I. KANEOKA, M. KONG, H. KINOSHITA, K. KOBAYASHI, Y. OHNA ...1968 Volume 20 Issue 2 Pages 101-105
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSDownload PDF (444K) -
Mitiyasu OHNAKA, Hajimu KINOSHITA1968 Volume 20 Issue 2 Pages 107-110
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSDownload PDF (319K) -
A. K. KAMRA1968 Volume 20 Issue 2 Pages 111-113
Published: June 20, 1968
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSDownload PDF (244K)
- |<
- <
- 1
- >
- >|