• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.253-254
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• 2012

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.119-130
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• 2013

We developed a method for inverting magnetic data to recover the 3D susceptibility models. The major difficulty in the inversion of the potential data is the non-uniqueness and the vast computing time. The insufficient number of data compared with that of inversion blocks intensifies the non-uniqueness problem. Furthermore, there is poor depth resolution inherent in magnetic data. To overcome this non-uniqueness problem, we propose a resolution model constraint that imposes large penalty on the model parameter with good resolution; on the other hand, small penalty on the model parameter with poor resolution. Using this model constraint, the model parameter with a poor resolution can be effectively resolved. Moreover, the wavelet transform and parallel solving were introduced to save the computing time. Through the wavelet transform, a large system matrix was transformed to a sparse matrix and solved by a parallel linear equation solver. This procedure is able to enormously save the computing time for the 3D inversion of magnetic data. The developed inversion algorithm is applied to the inversion of the synthetic data for typical models of magnetic anomalies and real airborne data obtained at the Geumsan area of Korea.

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.131-138
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• 2013

We developed a method for inverting magnetic data to image 2D susceptibility models. The major difficulty in the inversion of the potential data is the nonuniqueness. Furthermore, generally the number of inversion blocks are greater than the number of the magnetic data available, and thus the magnetic inversion leads to under-determined problem, which aggravates the nonuniqueness. When the magnetic data were inverted by the general least-squares method, the anomalous susceptibility would be concentrated near the surface in the inverted section. To overcome this nonuniqueness problem, we propose a new resolution model constraint that is calculated from the parameter resolution. The model constraint imposes large penalty on the model parameter with good resolution, on the other hand small penalty on the model parameter with poor resolution. Thus, the deep-seated model parameter, generally having poor resolution, can be effectively resolved. The developed inversion algorithm is applied to the inversion of the synthetic data for typical models of magnetic anomalies and is tested on real airborne data obtained at the Okcheon belt of Korea.

• 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.

• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.217-227
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• 2009

Heavy minerals in the marine sand near Haeju bay, Hwanghae-do, North Korea were separated using the gravity and the magnetic separators. And their mineralogical study was carried out. Ilmenite, magnetite, hematite, zircon and monazite were observed as the valuable minerals, and quartz, orthoclase, muscovite, hornblende and garnet existed as gangue minerals. In the result of quantitative analysis with SIROQUANT program, the contents of the valuable minerals separated with the 2nd gravity separation (the shaking table separation), the 1st magnetic separation (rare earth magnetic separation) and the 2nd magnetic separation (the Eddy current magnetic separation) were increased into 4%, 10% and 76~89% (under the condition of 7000 G and 10000 G in magnetic strength), respectively. The contents of ilmenite, monazite and zircon recalculated from the chemical composition differed from the results of the quantitative analyses by SIROQUANT program, but the entire tendency bears some analogy with it. Under the conditions of 7000 G and 10000 G in 2nd magnetic separation the contents of ilmenites were concentrated with 53% and 66%, respectively. The content of monazite was 1.2% in the magnetic fractions of the 1st magnetic separation. The content of zircon was shown 1.4% under the condition of 10000 G in the 2nd magnetic separation, and was displayed 9% in +50 mesh of non-magnetic fraction of 1st magnetic separation, especially.

• 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.

• Resources Recycling
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• v.28 no.3
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• pp.53-58
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• 2019

Pb dross has been generated from recycling processes of waste acid lead batteries, and proper treatment of Pb dross was required because it contains As component, which has been found to be toxic. This study is aimed at concentrating As component by magnetic separation of ground product obtained from ball and mixer milling of Pb dross. No arsenic component was detected in the non-magnetic product of 10000 G magnetic separation using ground product with $-150{\mu}m$ by ball milling, and As could be concentrated upto 18.87 % by further 2000 G magnetic separation. The ball mill ground product with over $300{\mu}m$ was ground again by mixer mill to less than $150{\mu}m$, and then magnetic-separated by 4000 G followed by 2000 G magnet. The As component was concentrated upto 21.021 % in the magnetic fraction of 2000 G. It was confirmed that As component exsit as $Fe_2As$ by XRD measrument. These results indicate that As component could be concentrated from 0.6 % in the Pb dross to 21.021 % in the magnetic fraction by milling followed by magnetic separation.

• Resources Recycling
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• v.10 no.3
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• pp.43-50
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• 2001

Characteristics of crushing and magnetic separation on the spent batteries, were investigated for reclaiming spent carbon-zinc and alkaline manganese dioxide batteries. Crushing of carbon zinc battery was easier than that of alkaline $MnO_2$battery using impact type crusher with rotary blades. Most of magnetic products were distributed in the range of 8 mesh size. With crushing 1 ton of spent carbon-zinc and alkaline $MnO_2$batteries respectively, magnetic separation of 8 mesh oversize particles, we can get 214 kg and 235 kg of magnetic products which is composed of 94% and 88% of Fe.

• The Science & Technology
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• v.9 no.8 s.87
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• pp.23-27
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• 1976

우리나라에서 본격적으로 물리탐사를 시도한것은 1958~1960년에 실시한 항공자력탐사로서 그후 현재까지 불과 20년이 지나지 않았다. 그간 물리탐사의 기술발전으로 자원탐사분야에 많은 공헌이 있었다. 현재까지 주로 적용된 분야는 철자원탐사를 위한 자력탐사, 지하수조사를 위한 전기비저항탐사동, 연등의 통화금속광물탐사를 위한 각종 전기탐사, 제3기층 지질구조와 땜공사, 공업단지조성등의 기반암조사, 그리고 광산의 갱내 출수조사등을 위한 탄성파탐사, 우라늄자원을 위한 방사능탐사, 그리고 해저지질 및 자원조사를 위한 해상물리탐사등이다. 이와 동시에 석탄층조사를 위한 전기탐사 및 Model연구자력탐사의 전산처리 적용, 그리고 광물 및 암석의 물리적 성질등 학술분야에 대한 기초연구도 계속하여 왔다. 우리나라에 있어 물리탐사의 적용조건은 비교적 험악한 지형, 복잡한 지질구조, 광상의 불규칙 또는 소규모의 발달과 산재등이다. 이와 같은 특징은 탐사해석의 정도를 높이기 위하여 보다 고도의 과학기술문제의 해결을 요구하고 있으며 이와 동시에 현대적 탐사방법과 연구개발로 대상자원의 탐사지역확대와 지하심부 탐사등이 당면과제이다. 기술과제로서는 석탄 및 기타자원에 대한 물리검층탐사, 경상계 지질구조구명을 위한 탄성파탐사 및 동력탐사의 적용, 항공자력, 전자 및 방사능탐사 및 해양의 각종물리탐사의 기술개발이 있으며 그외 탐사자료의 전산처리기술 및 지구과학의 기초연구등이 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.343-347
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• 2012

Non-linear equalization techniques using decision feedback structure are highly demanded for cancellation of intersymbol interferences occurred in severe channel environments. In this paper decision feedback structure is applied to the linear blind equalizer algorithm that is based on information theoretic learning and a randomly generated symbol set. At the decision feedback equalizer (DFE) the random symbols are generated to have the same probability density function (PDF) as that of the transmitted symbols. By minimizing difference between the PDF of blind DFE output and that of randomly generated symbols, the proposed DFE algorithm produces equalized output signal. From the simulation results, the proposed method has shown enhanced convergence and error performance compared to its linear counterpart.