• Korean Journal of Mineralogy and Petrology
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• v.37 no.3
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• pp.139-153
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• 2024

Recently, resources-rich advanced countries are putting more effort into mineral resource exploration as mineral resource depletion worsens along with deepening resource nationalism regarding mineral resources. Therefore, one of the methods used to explore mineral resources is to explore through the chemical composition of mineral. Pyrite, which is formed throughout the mineralization process and regardless of the mineral commodity type, is widely used as major geochemical indicator in mineral deposit exploration using content and list of trace elements in the pyrite. In this paper, the author aims to report on indicator elements that can be used when exploring lead-zinc orebody by studying the occurrence and chemical composition of pyrites from wallrock, wallrock alteration and lead-zinc orebody in the Janggun lead-zinc deposit. This deposit is hydrothermal replacement deposit formed by reaction of lead and zinc-bearing hydrothermal fluid and Paleozoic Janggum limestone formation. The wallrock alteration that is remarkably recognized with Pb-Zn mineralization at this hydrothermal replacement orebody consists of mainly rhodochrositization with minor of dolomitization, pyritization, sericitization and chloritization. Pyrite, which is occurred from wallrock, wallrock alteration, and lead-zinc orebody, is classified into three types (Py I type, Py II type, and Py III type) based on the texture, occurrence and paragenetic relationship. Pyrite on the basis of paragenetic sequence are as followed : Py I type (wallrock and wallrock alteration) → Py II type (wallrock alteration and Pb-Zn orebody) → Py III type (wallrock alteration and Pb-Zn orebody). Trace elements with a large content change in pyrite by all types are Mn, As, Ag, Sb and Pb elements, but trace elements with a small content change in pyrite are Zn, Cu, Cd, Se, Te, Co, Ni, Au, In and Sn elements. The substitution of these elements in all pyrite types is as followed: Fe²⁺↔Co²⁺ substitution (Py I type), 3Fe²⁺↔Ag¹⁺+(Mn²⁺+Ni²⁺+As²⁺)+(As3++Sb3+) substitution (Py II type) and 3Fe²⁺↔Ag¹⁺+(Mn²⁺+As²⁺+Pb²⁺)+(Mn³⁺+As³⁺+Sb³⁺), S^1-↔(As^1-+Sb^1-) substitution (Py III type). This means that Mn, As, Sb, Ag and Pb elements were enriched during evolution of hydrothermal fluid. Therefore, based on the above research results, pyrite is a useful mineral for exploration of lead-zinc orebody. And when exploring lead-zinc orebody with similar geological conditions, lead-zinc orebody is explored through the enrichment of as indicator elements.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.2
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• pp.147-150
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• 2003

Water toxicity monitoring based on the continuous cultivation of Photobacterium phorphoreum is presented. Normally, after 10 days of operation, a dark variant, which emits no light, appears and dominates the population, resulting in a rapid decrease in bioluminescence. Therefore, to overcome this problem, a fluidized-bed reactor is used in which alginate-immobilized cells are grown and leaking cells are continuously released into the effluent Experimental results revealed that the dominance of dark variants was suppressed inside the immobilized beads, thereby mitigating the rapid loss of bioluminescence. Plus, a high dilution rate (1.2 h$\^$-1/) prevented the occurrence of other microbial contamination in the reactor The concentration and bioluminescence of the released cells were sufficient to measure the water toxicity for more than 4 weeks.

• Ocean Science Journal
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• v.43 no.4
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• pp.183-193
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• 2008

Oncaea venusta Philippi, 1843 has been known as having some different size groups, but recent genetic study for cyt b and ITS 1 (Elvers et al. 2006) suggests that these size groups can be considered as different species. Of these size groups, the largest O. venusta Philippi and the smallest O. venella Farran, 1929 were first described in Korean waters. The latter is easily distinguishable from the former in the following characteristics in addition to its small size: (1) length to width ratio of genital double somite of two genders smaller, and (2) female second pediger bearing inconspicuous dorso-posterior swelling. Oncaea venusta and O. venella co-occur in Korean waters during spring to fall, but their occurrence patterns seasonally differ: the former shows higher density in fall while the latter does in summer.

• Journal of the Korean housing association
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• v.17 no.4
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• pp.131-143
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• 2006

Nowadays, diverse mass media discovers and introduces outstanding management cases of apartment complexes to induce vital competitions of constructors and active participation of residents to apartment management. This study statistically analyzed the management issues of outstanding apartment complexes that have been introduced by mass media with lexical criteria to examine the characteristics of their exemplary management. The key issues of outstanding apartment management are summarized as: efficient management of convenient facilities for residents, community activities based on residents' participation, and maintenance of pleasant living environments through transparent management. Also, the result of the relation arrangement of co-occurrence word from a Social Network Analysis included three key concepts of multi-family housing management - Maintenance Management, Operating Management, and Community Life Management - with emphasis on 'residents' and 'apartment complexes.' However, Operating Management was relatively deemphasized.

• Hwankyungkyoyuk
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• v.3 no.1
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• pp.78-84
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• 1992

The occurrence of acid precipitation in Japan is one of major concerns among Japanese scientists in environmental sciences. The annual mean pH observed is in the range of 4.6-4.8 and these values are higher than the values observed at the background stations in Korea and Northern China. We interpret that the low pH values occurring in Japan are mainly due to the precursors originating from Japan and from Southern China. In view of environmental education, interestingly the Prime Minister of Japan directly gives administrative support for acid rain monitoring and related studies Also, Japanese provide environmental education for their children in primary and secondary schools to instill 'green' concept. It is found that the role of scientists, media, governments and industries in Japan is very efficient for the increase in co-operation and environmental benefits.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.139-143
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• 1997

The doping effects of Mg and/or Fe ions on congruent LiNbO$_3$ single crystal growth were studied in order to clarify the roles of MgO in Fe doped LiNbO$_3$ single crystals. The effective distribution coefficienct of Fe was found decreased drastically from 0.85 to 0.5 by the addition of MgO into the LiNbO$_3$ melt. M ssbauer spectra revealed that the addition of MgO reduces the occurrence of Fe2+ ions during growth in air. Therefore, it is likely that there would be two important roles of MgO in Fe doped LiNbO$_3$. One is to suppress the incorporation of all Fe ions, and the other is to reduce the concentration of Fe2+ ions among the total Fe ions.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.115-119
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• 2014

As long as the prognosis of teeth remains a matter of concern, the endodontic-periodontal relationship will be considered a challenge for the clinician. Many etiologic factors, including bacteria, fungi, and viruses, plus other contributing factors, such as trauma, root resorptions/perforations, and dental malformations, play a role in the co-occurrence of endodontic and periodontal lesions. Whatever the cause, a correct diagnosis on which to base the treatment plan is the key to successful maintenance of the tooth. This article reports the successful endodontic management of a furcation lesion in a mandibular molar that was nonresponsive to a previous periodontal surgical graft. The case had presented a diagnostic challenge for the clinicians, and this article reviews the key points that can lead to a correct diagnosis and treatment planning.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.365-370
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• 1997

In this paper we suggest a development of surface defect inspection algorithms for cold mill strip using tree structure. The defects which exist in a surface of cold mill strip have a scattering or singular distribution. This paper consists of preprocessing, feature extraction and defect classification. By preprocessing, the binarized defect image is achieved. In this procedure, Top-hit transform, adaptive thresholding, thinning and noise rejection are used. Especially, Top-hit transform using local min/max operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, histogram-ratio features are calculated. The histogram-ratio feature is taken from the gray-level image. For the defect classification, we suggest a tree structure of which nodes are multilayer neural network clasifiers. The proposed algorithm reduced error rate comparing to one stage structure.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.4
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• pp.48-57
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• 1992

This paper addresses the estimation of the shift vector from aerial image sequences. The conventional feature-based and area-based matching methods are simulated for determining the suitable image registration scheme. Computer simulations show that the feature-based matching schemes based on the co-occurrence matrix, autoregressive model, and edge information do not give a reliable matching for aerial image sequences which do not have a suitable statistical model or significant features. In area-based matching methods we try various similarity functions for a matching measure and discuss the factors determining the matching accuracy. To reduce the estimation error of the shift vector we propose the reference window selection scheme. We also discuss the performance of the proposed algorithm based on the simulation results.

• Proceedings of The KACE
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• 2017.08a
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• pp.37-40
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• 2017

본 논문에서는 국가 연구 보고서의 공기 관계 정보와 제목, 요약 등에 가중치를 적용한 유사도 계산방법을 제안한다. 이를 위해 국가 연구개발 보고서에서 텍스트를 추출하여 한 문장 단위로 문서를 분할하고, 기본 불용어와 보고서에서 특징적으로 나타나는 불용어를 처리하고 형태소 분석을 한 뒤 공기관계를 추출하였다. 또한 문서의 유사도 계산시 정확성을 높이기 위해 제목과 요약 부분에 가중치를 부여하였다. 이를 통해 본 논문에서 제안하는 방법이 문서 검색 라이브러인 루씬(Lucene)을 이용한 방법보다 2.5%의 검색성능 향상을 그리고 Knn-휴리스틱 방법보다는 1.1%의 검색성능 향상을 보였다. 이러한 결과를 통해 문서의 요약과 제목 그리고 공기관계 정보가 연구보고서의 유사도를 계산 하는데 영향을 미친다는 것을 보였다.