• The Journal of the Petrological Society of Korea
• /
• v.9 no.4
• /
• pp.254-270
• /
• 2000

To clarify the geological structure of North Sobaegsan Massif in the Sangunmyeon area, Bonghwagun, Korea, where the Yecheon Shear Zone passes and the NE-SW and E-W trending structural lineaments are developed, the rock-structures of its main constituent rocks(Precambrian Won-nam Formation and Mesozoic Hornblende Granite) were examined. In this area, the geological structure was formed at least by four phases of deformation after the formation of gneissosity or schistosity of the Wonnam Formation: one deformation before D2 ductile shearing related to the for-mation of the Yecheon Shear Zone and two deformations after that. The NE-SW and E-W trending structural lineaments were formed by a giant open or gentle type of F4 fold, and their trends before D4 deformation are interpreted to be parallel to the orientation(ENE-WSW trend) of folded surface in the F4 hinge zone. The structural features of Dl-D3 deformations and their relative occurrence times are as follows. Dl deformation is formative period of the boudin structures and ENE-WSW trending isoclinal folds with sub-horizontal hinge lines and steeply inclined axial surfaces. D2 deformation is that of the mylonite foliation, stretching lineation and Z-shaped asymmetric folds related to top-to-the ENE dextral strike-slip shearing on the distinct foliations of Wonnam Formation(after intrusion of Mesozoic Hornblende Granite). D3 deformation is that of the ENE trending S-shaped asymmetric folds with sub-horizontal hinge lines and axial surfaces related to normal-slip shearing on the distinct foliations. It is expected that the result will be contributed to as valuable data for interpreting the tectonic evolution of the North Sobaegsan Massif and the Northeast Ogcheon Belt whose tectonic lineaments are changed from NE-SW to E-W trends at the Sindong-Bonghwa line.

• Journal of the Korean Magnetics Society
• /
• v.22 no.2
• /
• pp.49-57
• /
• 2012

From among the NDT (Non-Destructive Testing) methods, the MFL (Magnetic Flux Leakage) PIG (Pipeline Inspection Gauge) is especially suitable for testing pipelines because the pipeline has high magnetic permeability. MFL PIG showed high performance in detecting the metal loss and corrosions. However, MFL PIG is difficult to detect the crack which occured by exterior-interior pressure difference in pipelines and the shape of crack is very long and narrow. Therefore, the new PIG is needed to be researched and developed for detecting the cracks. The CMFL (Circumferential MF) PIG performs magnetic fields circumferentially and can maximize the magnetic flux leakage at the cracks. In this paper, CMFL PIG is designed and the distribution of the magnetic fields is analyzed by using 3 dimensional nonlinear finite element method (FEM). By Simulating and Measuring the magnetic leakage field, it is possible to detect of axial cracks in the pipeline.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.4 no.3
• /
• pp.210-222
• /
• 1994

The characteristics of flows, temperatures, and concentrations of oxygen are numerically studies in the Czochralski furnace with a uniform axial magnetic field. Important governing factors to the flow fields include buoyancy, thermocapillarity, centrifugal force, magnetic force, diffusion and segregation coefficients of the oxygen, evaporation coefficient in the form of SiO, and ablation rate of crucible wall. With an assumption that the flow fields have reached the steady state, which means that two velocity components in the meridional plane and circumferential velocity, temperatures, electric current intensity become non-transient, then unsteady concentration field of oxygen has been analyzed with an initially uniform oxygen concentration. Oxygen transports due to convection and diffusion in the Czochralski flow field and oxygen flux through the growing crystal surface has been investigated.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.7 no.3
• /
• pp.30-37
• /
• 2003

Spray angle of dual swirl injector is established according to the velocity ratio at orifice exit. Due to the internal mixing at recess and lack of correlation for the combined two fluid injection, prediction of spray angle is very difficult. This study deal with experimental work and numerical simulation on spray angle with different recess length. Among the multiphase flow models, the VOF model was selected to simulate the spray angle. Feasibility of numerical analysis are confirmed by comparing the results with the experimental data, and the effect of recess on spray angle are analyzed for single and combined spray case.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.6
• /
• pp.171-182
• /
• 2003

Tire vibration modes are known to play a key role in vehicle ride and comfort characteristics. Inputs to the tire such as impacts, rough road surface, tire nonuniformities, and tread patterns can potentially excite tire vibration. In this study, experimental modal analysis on the tire in ground contact are performed by a 3-D impact at the center of contact patch to investigate which modes of tire influence the vibration of wheel and axle. Through the experiment, the vibration transmission properties from tire to axle are examined. And we have compared the influential tire modes when the tire is excited by a vertical impact with those when excited by the 3-D impact. Additionally, the modes of ground contact tire are compared with those of the suspended tire.

• Annual Conference of KIPS
• /
• 2002.11a
• /
• pp.35-38
• /
• 2002

본 논문에서는 3차원 재구성에 있어서 필수 불가결한 기술인 카메라 교정 방법에 있어서 특정 교정 물체나 또는 영상에서의 제약 조건 등을 요구하지 않고 영상 내에 산재되어 있는 기하학 정보를 이용하여 카메라 내부 파라미터를 추출하고 영상간의 카메라 움직임을 계산하여 3차원 재구성하는 알고리즘을 제안한다. 공간에서의 직교하는 평행선들의 집합이 만들어 낸 자 축 방향으로의 3개의 소실 점을 이용하면 그 투영 영상에 대한 카메라 내부 파라미터를 얻을 수 있게 된다. 또 한 영상간의 대응점 관계를 이용하면 두 영상 사이의 상대적인 카메라의 회진 및 이동 성분을 얻어 낼 수 있다. 따라서 카메라의 내부, 외부 성분을 추출함으로써 사영 행렬을 계산하고 역 투영 방법에 의해서 3차원 재구성을 구현하게 된다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.8 no.4
• /
• pp.305-313
• /
• 1996

CTD measurements were conducted in the Nakdong estuary on the several sections or along-plume and cross-plume directions in 1993 and 1994. Internal Froude number Fi=0.22-0.35 in ebb tides and 0.14 in flood tides suggest that Nakdong river plume may go farther seawards in the along-plume direction with little mixing with the adjacent sea water after the construction of Nakdong river barrier. From Dadae-Po to Gaduk-Do section of cross-plume direction, three cores of low salinity were found. The main plume outflows from the newly made channel by cutting Ulsuk-Do after the construction of barrier. The low salinity core found near Gaduk-Do is the plume patch advected by tidal currents. Rossby deformation radius varied with the tidal cycle so that Coriolis effect is strengthened in flood tides to deepen the isohalines westwards to the Gaduk-Do site. Internal wavelike shape was found in the section of cross-plume direction during ebb tides. Richardson number of the section suggests the possibility of forming internal wave but more precise observations are necessary.

• Tunnel and Underground Space
• /
• v.13 no.1
• /
• pp.33-43
• /
• 2003

Field investigations of the orientations of discontinuity planes inside the borehole for designing the underground rock structures have been depend solely on the borehole image-taking techniques. But, borehole image-taking has to be processed after the completion of drilling operation and also requires the handling of highly expensive apparatus so that practical application is very restricted. In this study Discontinuity Orientation Measurement (DOM) drilling system and discontinuity analysis model RoSA-DOM are developed to acquire the reliable information of rock structure by analyzing the characteristics of joint distribution. DOM drilling system retrieves the rock core on which the reference line of pre-fixed drilling orientation is engraved. Coordinates of three arbitrary points on the joint surface relative to the position of reference line are assessed to determine the orientation of joint plane. The position of joint plane is also allocated by calculating the location of core axis at which joint plane is intersected. Then, the formation of joint set is analyzed by utilizing the clustering algorithm. Total and set spacings are calculated by considering the borehole axis as the scanline. Engineering applicability of in-situ rock mass around the borehole is also estimated by calculating the total and regional RQDs along the borehole axis.

• The Journal of the Petrological Society of Korea
• /
• v.11 no.3_4
• /
• pp.234-249
• /
• 2002

The Miwon-Boeun area in the central and northern part of Okcheon metamorphic zone, Korea, is composed of Okcheon Supergroup and Mesozoic Cheongju and Boeun granitoids which intruded it. The Okcheon Supergroup consists mainly of quartzite (Midongsan Formation), meta-calcareous rocks (Daehyangsan Formation, Hwajeonri Formation), meta-psammitic rocks (Unkyori Formation), meta-politic rocks (Munjuri Formation), meta-conglomeratic rocks (Hwanggangni Formation) in the study area, showing a zonal distribution of NE trend. Its' general trend is locally changed into NS to EW trend in and around high-angle fault of NS or NW trend. This study focused on deformation history of the Okcheon Supergroup, suggesting that the geological structure was formed at least by four phases of deformation. (1) The first phase of deformation occurred under ductile shear deformation of top-to-the southeast movement, forming sheath fold or A-type fold, asymmetric isoclinal fold, NW-SE trending stretching lineation. (2) The second phase of deformation took place under compression of NW-SE direction, forming subhorizontal, tight upright fold of M trend in the earlier phase, and formed semi-brittle thrust fault (Guryongsan Thrust Fault) of top-to-the southeast movement and associated snake-head fold in the later phase. (3) The third phase of deformation formed subhorizontal, open recumbent fold through gravitational or extensional collapses which might be generated from crustal thickening and gravitational instability. (4) The fourth phase of deformation formed moderately plunging, steeply inclined kink fold related to high-angle faulting, being closely connected with the local change of NE-trending regional foliation into NS to EW direction of strike in the vicinity of the high-angle fault.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.145-145
• /
• 1999

La-Ca-Mn-O (LCMO) 박막에서 초거대 자기 저항 효과와 발견된 이후 자기 센서와 고밀도 자기 저장 매체로서 응용하기 위한 연구가 진행되고 있다. 그러나 현재 대부분의 증착은 타겟과 박막간의 조성의 일치를 위하여 PLD 방법을 이용하고 있으며 RF magnetron sputtering 법으로 증착한 예는 많이 보고되고 있지 않으며 특히 적층 성장시킨 예는 아직 보고되지 있지 않다. 또한 LCMO와의 낮은 격자 상수 불일치를 보이는 SrTiO3와 LaAlO3 기판에 LCMO 박막을 성장시킬 경우 LaAlO3의 경우 XRD rocking curve의 curve의 FWHM 값이 SrTiO3 상에 증착시킨 것의 10배 이상의 값을 보인다는 것은 주목할 만한 사실이다. RF magnetron sputtering 법을 이용하여 LaAlO3 기판상에 145nm MCMO 박막을 적층성장시켰다. XRD $ heta$-2$\theta$ scan을 통해 박막이 c-축 배향한 것을 확인할 수 있었으며 RBS 분석결과 4.98%의 minimumyield를 보였으며 이로부터 박막이 적층성장한 것을 확인할 수 있었다. LCMO (200) peak의 XRD $\theta$-rocking 결과 FWHM의 값은 0.311$^{\circ}$를 보였으나 2개의 피크가 존재하는 것을 볼 수 있었다. 따라서 기판의 (200) 피크를 XRD $\theta$-2$\theta$ scan에서 0.3$^{\circ}$ 간격으로 두 개의 피크를 관찰할 수 있었는데 이는 기판과 박막간의 stress로 인한 tetragonal distortion에 의한 것으로 알려져 있었다. 따라서 기판상에 박막이 어떤 식으로 적층 성장되었는지를 RBS를 이용하여 <001>과 <011> 방향으로 2MeV He++를 주입하여 0.1$^{\circ}$ 간격으로 틸팅을 해본 결과 <001> 방향에서는 1.12$^{\circ}$의 차이를 보였다. 이는 기판과의 compressive stress로 인해 c축 방향으로 늘어났으며 stress relaxed layer는 XRD 결과와는 달리 관찰할 수 없었다. 이러한 현상의 기판 자체의 twin 구조로 인한 것으로 생각된다. RBS 분석후 고분해능 XRD를 이용해 LCMO (200) peak의 $\theta$-rocking 결과 이제R지 laAlO3 상 증착한 LCMO의 값으로는 제일 작은 0.147$^{\circ}$를 나타내었다.