• The Journal of Engineering Geology
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• v.8 no.3
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• pp.285-296
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• 1998

As a part of the study for understanding the deep geological structure of the Ogcheon Zone, both gravity and geomagnetic surveys are performed. A 70km survey line of which direction is nearly perpendicular to major faults in the southern tip of the Zone. The observed data are corrected and transformed into Bouguer and total magnetic intensity anomalies, respectively. Recent studies for petrology and geochemistry in the southwestern Ogcheon Zone in the vicinity of the survey line are reviewed for better interpretation. Both gravity and geomagnetic anomalies abruptly change around Janghung area, the southern boundary of the, Ogcheon Zone. This rapid increase of Bouguer anomaly around Janghung area can be explained by a deep seated normal fault with fairy large displacement between Precambrian gneisses and the denser intermediate plutonic rocks. It is believed that the fault acted an important role for the formation and evolution of the Ogcheon Zone. A pseudomagnetic intensity anomaly is calculated from the Bouguer anomaly assuming that the both anomalies are associated with the common source. From the origin of the survey line to the 50km point, the calculated anomaly coincides with observed magnetic anomaly. Whereas both anomalies show negative correlation in the outside 50km. From the residual Bouguer anomalies, the subterranean geological structure is provided through the iterative forward method. The initial model is obtained from informations about the surface geology as well as the results of the inverse method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.548-553
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• 2002

Most tasks of the large vertical or ceiling structures have been carried out by human power. Those tasks require us much operation costs and times, safety devices, etc. So the need of automation for those tasks have been rising. That automation needs a wall-climbing mobile vehicle. Most former researches are things about attachment devices and moving mechanisms. A wall-climbing mobile vehicle must be designed by a method different from the case of the vehicle of the horizontal environment. That is because gravity acts as a negative role on the stability of a wall-climbing vehicle. In this thesis, the particular shape characteristics of a wall-climbing mobile vehicle are derived by the wall-environment modeling. In addition, some design constraints of the permanent magnetic wheel as an attachment device was studied. According to those requirements and constraints, one specific wall-climbing mobile vehicle was designed and some experiments were made on the attachment ability of that vehicle.

• 한국지구물리탐사학회:학술대회논문집
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• 2010.10a
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• pp.149-150
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• 2010

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.208-214
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• 2020

In this study, we have developed a drone magnetic exploration system (proto-type) using a fluxgate magnetic sensor. Hardware of the system consists of a fluxgate magnetometer, an inertial measurement unit (IMU), a GPS, and a communication module. And we have developed monitoring software, which enables it to transmit the measured data to the ground control system (GCS) in real time. The measured magnetic data are finally saved as 1 Hz data after passing through a notch filter and a band-pass filter. For verification of this system, a preliminary test was conducted to check the magnetic responses of a magnetic object first, then the field test was carried out in two iron mines. We tested the developed system on the field test in Pocheon, Gyeonggi and Jeongseon, Gangwon. The magnetic data from the developed drone system was very similar to those from unmanned airship system developed by Korea Institute of Geoscience and Mineral Resources (KIGAM). As a result, preliminary experiment and field test have demonstrated that this system is applicable for outdoor aeromagnetic exploration. It requires more studies to improve filter function and instrument performance to minimize noise in the future.

• Journal of the Korean Magnetics Society
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• v.10 no.2
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• pp.81-85
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• 2000

Crystallographic and magnetic properties of the Mn-doped orthoferrite LaFe$_{1-x}$Mn$_{x}$ O$_3$(0.0$\leq$x$\leq$O.4) system have been investigated by means of x-ray diffractometry, M ssbauer spectroscopy, vibrating sample magnetometer and super-conducting quantum interference device. The structure of the system was found to be orthorhombic distorted perovskite structure. At room temperature, the M ssbauer spectra for x=0.0 consists of one Zeeman sextets from Fe$^{3+}$ ions at octahedral sites. The M ssbauer spectra of two Zeeman sextets (x$\leq$0.1) change one Zeeman sextets and a paramagnetic doublet (x=0.4). The saturation magnetization increases but the coercivity decreases with increasing x in LaFe$_{1-x}$Mn$_{x}$ O$_3$.

• Economic and Environmental Geology
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• v.24 no.4
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• pp.421-434
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• 1991

Ground magnetic surveys were conducted at four areas where the Yangsan fault, the most prominent lineament in the Kyeongsang basin, appears to be passed through. For data processing, IGRF correction, upward continuation and reduction-to-the-pole were performed. The automatic inversion by using a matrix computation method, which takes the depth to bottom layer of the horizontal two layer structure as the model parameter, has been attempted to delineate the subsurface structure. Upward continuation of the surface magnetic map to the same level of the aeromagnetic survey (KIER, 1989) resulted in very similiar patterns to those of aeromagnetic data. Subsurface modeling of eight profile data show that the strike and dip of the Yangsan fault in study areas are $N6^{\circ}-15^{\circ}E$, and near vertical to somewhat eastward, repectively, despite of the local lithological contrast of each study area. It seems that the magnetic effect of faulting in the study area 1, which locates in the most northern part of the survey areas, is disturbed by that of igneous intrusion. At study area 2, the possibility of volcanic or igneous intrusion, which is 200-300 meters wide along the fault plane was presented. At study area 3, unlike other study areas, distinct fracture zone of 500-700 meters in width was revealed along the surface fault line. The andesitic rocks of the study area 4 have very high susceptibilities and the fault line on surface of this area was shifted about 500 meter eastward, as compared with the inferred fault line by the previous study.

• 한국지구물리탐사학회:학술대회논문집
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• 2010.10a
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• pp.151-152
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• 2010

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.9-9
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• 2003

최근에 Fe-CU, Fe-Si 등과 같이 자성금속과 비자성금속화합물에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 기계적 합금법으로 제작한 Co/sub 5/C/sub 95/ 나노미립상 합금의 구조와 자기적 성질을 조사하였다. 그림(1)은 EXAFS 스펙트럼의 푸리에변환이다. 이로부터 합금화시간에 따라 Co-Co 결합은 점차적으로 작아지며 Co-C 결합이 진행됨에 알수 있다. 그림(2)은 합금화시간에 따른 포화자화값과 보자력의 크기이다. 포화자화는 합금화 시간에 따라 연속적으로 작아졌으며 보자력은 커지다가 작아지는 경향을 보였다. 포화자화가 작아지는 것은 Co-C 결합이 생기면서 Co의 쌍을 이루지 않은 전자가 C의 전자와 쌍을 이루면서 상쇄되기 때문인 것으로 보인다. 보자력의 거동은 Co 미립자가 다자구영역으로부터 단자구영역으로 전환되기 때문인 것으로 해석될수 있다. Co 미립자는 C의 캡슐형에 싸여있으며 60시간과 100시간에서 Co 미립자의 크기는 X-ray 회절선의 넓어짐으로부터 Scherrerr 공식을 이용하여 계산한 결과 18nm 와 15nm 정도가 됨을 알 수 있었다. 연구를 통하여 Co/sub 5/C/sub 95/ 나노미립상합금을 기계적합금법으로 만들 수 있음을 알 수 있었다. 이론적인 계산에 의하면 초상자성 Co 입자의 크기는 8.2nm 정도가 되었으며 본 실험에서 최종 입자의 크기는 15nm까지 작아졌다.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.69-76
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• 2004

Most tasks of the large vertical or ceiling structures have been carried out by human power. Those tasks require us much operation costs and times, safety devices, etc. So the need of automation for those tasks have been rising. That automation needs a wall-climbing mobile vehicle. Most former researches are things about attachment devices and moving mechanisms. A wall-climbing mobile vehicle must be designed by a method different from the case of the vehicle of the horizontal environment. That is because gravity acts as a negative role on the stability of a wall-climbing vehicle. In this thesis, the particular shape characteristics of a wall-climbing mobile vehicle are derived by the wall-environment modeling. In addition, some design constraints of the permanent magnetic wheel as an attachment device was studied. According to those requirements and constraints, one specific wall-climbing mobile vehicle was designed and some experiments were made on the attachment ability of that vehicle.

• Economic and Environmental Geology
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• v.48 no.4
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• pp.313-324
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• 2015

This study constructed a 3D geological model for Uggi Nuur Fe-Mn mineralization zone in Mongolia, and the 3D geological distribution is cross-analyzed with magnetic anomaly distribution to figure out relationship between ore zone and subsurface geology. As a result of 4 step 3D modeling procedures including geological cross section, surface modeling, foliation modeling and solid modeling, the geology of the both study area is bordered by faults in NW direction with Munguntessj formation being located in the west side of the fault while Yashill formation is located on the other side of the fault. Moreover, the strike direction of foliation in the both formation shows same directional pattern with the NW faults. The magnetic anomaly distribution reveals that higher anomaly values are concentrated to near the ground surface. The analyses of 3 dimensional distribution between subsurface geology and magnetic anomaly indicates that higher anomaly is mainly distributed over the Munguntessj formation as a elongated lens bodies whereas the magnetic anomaly is evenly found in the both of Munguntessj formation and Yashill formation in the study area 2. It infers that volcanic activities associated mineralization occurred during silurian period, and the mineralized zone is thought to be realigned along the geological structures caused by later stage tectonic activities.