• Korean Journal of Heritage: History & Science
• /
• v.41 no.1
• /
• pp.21-33
• /
• 2008

In this study, the researcher examined archaeomagnetic secular variation of Chungcheong Region through measured data of archaeomagnet obtained from 34 relics, which discovered in the baked earth from varied historic sites within the region. Furthermore, the researcher closely reviewed regional differences of geomagnetic field in the domestic territory. Reviewing the comparison between the measured data of archaeomagnet in Chungcheong Region and the archaeomagnetic secular variation of Japan, which has difference in distance, it reveals a noticeable change in declination by tilting more than 10 degree toward East in the year of about A.D. 300, although the feature of whole variation is quite similar. In other period of times, it was confirmed that the regional differences of geomagnetic field in which the magnetic dip became deeper to some degree, and the declination was tilted westward a little bit. Such patterns do not differ significantly from the pattern of entire archaeomagnetic secular variation of our country, and even in the direct comparison to the data of Chungcheong Region, the distinct regional difference in both periods before and after Christian era was not confirmed. The fact may become clearer that, when the volume of the measured data of archaeomagnet increases further, and when more data connected with varied time period are filled, the problem such as deviation of the measurement period of archaeomagnet caused by the regional difference of geomagnetic field would not be worrisome issue, especially in Korean territory, judging from the measured data of archaeomagnet of historic relics in Chungcheong Region. Besides, as great efforts are being exerted in order to get the most reliable measured data as much as possible in taking both samples and measurement, it is thought that there would be no problem not only in the issue of deviation of the measurement period involving with the measured data of archeomagnet, but also in the aspect of reliability of data.

• Transactions of the Korean hydrogen and new energy society
• /
• v.10 no.2
• /
• pp.119-130
• /
• 1999

After preparing $Mg_2Ni_{1-x}{^{57}}Fe_x$(x=0.015, 0.03, 0.06, 0.12 and 0.24) alloys, they were studied by $M{\ddot{o}}ssbauer$ resonance. The $M{\ddot{o}}ssbauer$ spectra of x=0.015 and 0.03 alloys exhibit two doublets (doublet 1, 2). That of x=0.06 alloys shows two doublets (doublet 1,2) and one six-line, and those of x=0.12 and 0.24 alloys have only one six-line. The doublet 1 for x=0.015, 0.03 and 0.06 alloys is considered to result from a fraction of Fe in excess showing a superparamagnetic behavior. The doublet 2 is considered to result from the Fe substituted for Ni in the $Mg_2Ni$ phase. The values of isomer shift 0.24 ~ 0.28 mm/s suggest that the iron exist in the state $Fe^{+3}$. The result that the quadrapole splitting of the doublet 2 is not zero shows that the distribution of electrons around the iron is asymmetric. Their values for the doublet 2, 1.20 ~ 1.38 mm/s, approach the value of quadrapole for the oxidation number +3. The six-line showing the magnetic hyperfine interactions results from the iron which has not substituted the nickel in the $Mg_2Ni$ phase. The $M{\ddot{o}}ssbauer$ spectra of the hydrided alloys with x=0.015 and 0.03 show six-line. This suggests that the iron segregates with the hydriding reaction. The analysis results of the $M{\ddot{o}}ssbauer$ spectrum, the variation of magnetization with magnetic field, Auger electron spectroscopy and electron diffraction show the segregation of Ni and the formation of MgO. This is considered to result from the reaction of the $Mg_2Ni$ phase with the oxygen contained in the hydrogen as impurity.