• Explosives and Blasting
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• v.21 no.4
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• pp.23-35
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• 2003

This study is to clarify the comparative relationship and a mechanical anisotropy of rock on the subject of granite distributed in the Namwon area Uniaxial compressive and Brazilian strengths with respect to the horizontal and vertical axes of granite are shown the linear relation. In the case of the result of the p-wave velocity measurement. it is represented that the velocity of vortical direction is faster about 10 to 15% than other two horizontal directions. The difference between velocities is caused by a developmental pattern of microcracks distributed in rock. Moreover, this result is very consistent with the result investigated through thin sections. The proportion of uniaxial compression strength to Index of point load strength ($Is_{(50)}$) is 18~20 times in case of granite. Uniaxial compressive strength is relatively good relationship with point load strength, Schmidt hammer rebound value, and tensile strength point load strength of them is the best comparative relationship. It is indicated that point load test is the most useful tool to estimate uniaxial compressive strength, comparing with other experimental methods.

• Journal of the Korean Magnetics Society
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• v.18 no.4
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• pp.147-153
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• 2008

It has been well-known that the Fe/GaAs heterostructure has a small lattice mismatch of 1.4% between Fe and GaAs, and the Fe layer is grown epitaxially on the the GaAs substrate. There are rich physics are observed in the GaAs/Fe interface, and the spininjection is actively studied due to its potential applications for spintronics devices. We fabricated Fe wedge layer in the thickness range $0{\sim}3.4$ nm on the GaAs(100) surface with 5-nm thick Au capping layer. The magnetic anisotropy of the Fe/GaAs system was investigated by employing Brillouin light scattering(BLS) measurements in this study. The spin wave excitation of Fe layer was studied as the function of intensity and the in-plane angle of external magnetic field, and thickness of Fe layer. Also these various dependences were analyzed with analytic expression of spin wave surface mode in order to determine the magnetic anisotropies. It has been found that the GaAs/Fe/Au system has additional uniaxial magnetic anisotropy, while the bulk Fe has biaxial anisotropy. The uniaxial anisotropy shows increasing dependency respected to decreasing thickness of Fe layer while biaxial anisotropy is reduced with Fe film thickness. This result allows the analysis that the uniaxial anisotropy is originated from interface between GaAs surface and Fe layer.

• Journal of Magnetics
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• v.14 no.1
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• pp.18-22
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• 2009

The shape anisotropy effect of a giant magnetoresistance-spin valves (GMR-SV) device with a glass/NiO/NiFe/CoFe/Cu/CoFe/NiFe layered structure for use in the detection of magnetic property of molecules within a cell was investigated. The patterned device was given uniaxial anisotropy during the sputtering deposition and vacuum post-annealing, which was performed at $200^{\circ}C$ under a 300 Oe magnetic field. The pattern size of the device, which was prepared through the photolithography process, was $2{\times}15\;{\mu}m^2$. The experimental results confirmed that the best design for a GMR-SV device to be used as a biosensor is to have both the axis sensing current and the easy axis of the pinned NiO/NiFe/CoFe triple layer oriented in the direction of the device's width, while the easy axis of the free CoFe/NiFe bilayer should be pointed along the long axis of the device.

• Proceedings of the Korean Magnestics Society Conference
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• 1999.04a
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• pp.130-131
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• 1999

• Proceedings of the Korean Magnestics Society Conference
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• 1997.11a
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• pp.108-109
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• 1997

• Proceedings of the Korean Magnestics Society Conference
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• 1997.11a
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• pp.110-111
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• 1997

• Proceedings of the Korean Magnestics Society Conference
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• 1999.04a
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• pp.100-101
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• 1999

• Proceedings of the Korean Magnestics Society Conference
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• 2001.04a
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• pp.56-57
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• 2001

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.243.1-243.1
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• 2008

• The Journal of Engineering Geology
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• v.18 no.2
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• pp.215-225
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• 2008

In order to investigate the influence factors to compressive and tensile strength of basalt in Cheju Island, rock samples of Pyosenri basalt, trachy-basalt and scoria were taken from Seoguipo-Si Seongsan-Eup area, and a series of uniaxial compressive strength test and Brazilian test were carried out. Especially, these tests were performed in consideration of the loading speed, the moisture content in rock sample, and the anisotropy of rock strength. The uniaxial compressive strength was increased gradually as the loading speed rose. The increasing quantity of uniaxial compressive strength had a difference in each rock types. Also, the strength was decreased with increasing the moisture contents in rock sample by pore water. As the result of test considering the anisotropy of rock strength, the compressive strength in condition of failure occurred parallel to stratified layer is decreased about 12-26% more than that in condition of failure occurred inclined to stratified layer.