• Title/Summary/Keyword: Pohang steel company

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Changes in Sedimentary Process and Distribution of Benthic Foraminifera in the Eastern Part of Kwangyang Bay, South Sea of Korea (광양만 동부해역의 퇴적과정 변화와 저서성 유공충 군집분포)

  • 김신정;김대철
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.1 no.1
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    • pp.32-45
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    • 1996
  • Analyses of surface sediment textures and recent benthic foraminifera were carried out to understand the change of sedimentary depositional processes in the eastern part of Kwangyang Bay. Echo-sounding images revealed that topographic change of the delta front sheet sand was caused by POSCO (Pohang Steel Company)'s dredging and reclaiming. The sand body prograded toward southeast. Fine sediments are distributed in the northeastern part of the study area. Identification of benthic foraminifera was conducted for the two selected cores from the sand body for the first time. Dominant species are Ammonia beccarii, Elphidium excavatum and Quinqueloculina lamarckiana. No abrupt change of benthic foraminiferal assemblage was observed from the sedimentary sequences.

Effect of Biocide (NaOCl) in Industrial Cooling Water on Biofilm Formation and Metal Corrosion. (공장냉각수에서 Biocide (NaOCl)가 생물막 형성 및 금속 부식에 미치는 영향)

  • 강용호;박대규
    • Microbiology and Biotechnology Letters
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    • v.30 no.1
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    • pp.86-90
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    • 2002
  • Cooling water sampled at Pohang Steel Company, Korea, was used to study the effect of biocide (NaOCl) on biofilm formation and metal corrosion. Planktonic microorganisms were killed in the presence of biocide (0.2% NaOCl) within 1.5 h, but not sessile microorganisms in biofilms even after one week. Black color of biofilms, possibly due to the activity of sulfate reducing bacteria, were made with the natural cooling waters, while orange color of biofilms were formed when cooling waters were autoclaved or when 0.2% NaOCl was added to the natural cooling waters. Microbially influenced corrosion rate in black color of biofilms was 2.3 fold higher than that in orange color of biofilms.

Economic Effects of the Privatization of the Public Enterprises through the People's Share Program (국민주방식(國民株方式) 공기업민영화(公企業民營化)의 경제적(經濟的) 효과분석(效果分析))

  • Song, Dae-hee;Song, Myung-hee
    • KDI Journal of Economic Policy
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    • v.14 no.2
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    • pp.3-27
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    • 1992
  • In 1988, the government provided to the low income people 34.1% of the stocks of Pohang Iron & Steel Company through the People's Share Program of Privatization for the first time, and then in 1989 21% of the share of the Korea Electric Power Corporation were also provided to the low income classes through the same way. The purpose of the People's Share Program was known to be to support the low income classes through participating the profit of public enterprises, and also to expand the capital market through the diversification of stock holding structure. Initially, the government planned that the government share of enterprises such as the Citizens National Bank, the Korea Telecommunication Authority would be sold to the low income classes through the People's Share Program step by step. The income support policy, however, was no longer driven after 1989 when the overall stock prices started to decline. In this paper we tried to measure the effect of the privatization scheme of the public enterprises through the People's Share Program. The problems of the People's Share Program of the Pohang Iron & Steel Commpany and the Korea Electric Power Corperation were also identified. Several implications of the privatization scheme of the public enterprise through the People's Share Program by stages were found. The People's Share Program was found to be a non-stable policy measure for the income support of low income classes. The efficiency impact of the privatization through the People's Share Program was found to be non-significant.

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Modeling of heat efficiency of hot stove based on neural network using feature extraction (특성 추출과 신경회로망을 이용한 열 풍로 열효율에 대한 모델링)

  • Min Kwang Gi;Choi Tae Hwa;Han Chong Hun;Chang Kun Soo
    • Journal of the Korean Institute of Gas
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    • v.2 no.4
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    • pp.60-66
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    • 1998
  • The hot stove system is a process that is continuously and constantly generating the hot combustion air required for the blast furnace. The hot stove process is considered as a main energy consumption process because it consumes about $20\%$ of the total energy in steel making works. So, many researchers have interested in the improvement of the heat efficiency of the hot stove to reduce the energy consumption. But they have difficulties in improving the heat efficiency of the hot stove because there is no precise information on heat transformation occurring during the heating period. In order to model the relationship between the operating conditions and heat efficiencies, we propose a neural network using feature extraction as one of experimental modeling methods. In order to show the performance of the model, we compare it with Partial Least Square (PLS) method. Both methods have similarities in using the dimension reduction technique. And then we present the simulation results on the prediction of the heat efficiency of the hot stove.

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A study on the Fracture of Coil Spring (파쇄기용 코일스프링의 파손에 관한 연구)

  • Jeong, Hyung-Sik;An, Se-Won;Lee, Jong-Hyung;Choi, Seong-Dae
    • Journal of the Korean Society of Industry Convergence
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    • v.9 no.1
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    • pp.51-59
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    • 2006
  • The study is diagnosis about fatigue failure phenomenon of heating coil spring (sup9) and heat treatment method that is used to crusher. Because more than 80~90% of damage announcement of breakdown of machine and construction is been caused in fatigue present state, fatigue failure became important leading person at design. Calculated design load is imposed repeatedly that fatigue breakdown is safe. Is phenomenon that change load is imposed in the construction continuously. Used coil spring applies heat 30minute by Quenching temperature $860^{\circ}C$ if see manufacturing process and temperature of gasoline of $50^{\circ}C$ keep after quench that know tempering a $460^{\circ}C$ 90minute a product be. If doto apply heat $950^{\circ}C$ material at rolling process historically before quenching, austenite formation clay pipe being done AGS(Austenite Grain Size) by 2.5~4 become. Apply heat quenching 30minute by $820^{\circ}C$ by improvement method and after quench that keep $50^{\circ}C$ in oil tempering if do $450^{\circ}C$, 90minute spring ideal formation sorbite formation of the river form and condition that satisfy most more than AGS 7 appeared. Also, we can secure authoritativeness through MT since shot peening processing.

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Development of a Temperature Control Model for a Hot Coil Strip using on-line Retrainable RBF Network (온라인 재학습 가능한 RBF 네트워크를 이용한 열연 권취 온도 제어 모델 개발)

  • Jeong, So-Young;Lee, Min-Ho;Lee, Soo-Young
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.36S no.8
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    • pp.39-47
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    • 1999
  • This paper describes on-line retrainable RBF network in order to control the coiling temperature for a hot coil strip at Pohang Iron & Steel Company(POSCO). The proposed neural network can be used for improving conventional rule-based lookup table, which generates a heat transmission coefficient. To cope with time-varying characteristics of hot coil process, additional synaptic weights for on-line retraining purposes are introduced to hidden-to-output weights of conventional RBF network. Those weights are locally adjusted to newly incoming test data while preserving old information trained with off-line past data. Hence the effect of catastrophic interference can be greatly alleviated with the proposed network. In addition, rejection scheme is introduced for reliability concerns. From the experimental results applied to the actual process, it is noticed that overall control performance represents about 2.2% increase compared to the conventional one.

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Spatial and Seasonal Patterns of Polychaete Community During the Reclamation and Dredging Activities for the Construction of the Pohang Steel Mill Company in Kwangyang Bay, Korea (광양제철소 건설을 위한 매립과 준설공사 기간중 저서 다모류 군집의 공간 및 계절 변화)

  • JUNG Rae-Hong;HONG Jae-Sang;LEE Jae-Hac
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.5
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    • pp.730-743
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    • 1997
  • Community structure and distribution patterns of benthic polychaetes were studied in Aug. 1983 and Feb. 1984 in Kwangyang Bay, Korea. During the study period, the large-scale reclamation and dredging operations were taking place. Polychaetes were composed of 76 species with a mean density of $342\;ind.{\cdot}m^{-2}$ during the summer 1983 and 77 species with a mean density of $437\;ind.{\cdot}m^{-2}$ during the winter 1984. Community structure indices were applied to the seasonal data. The stations influenced by the Seomjin river are characterized by a low species number and low diversity, while the stations located in channel regions represent high species richness and highdiversity. The inner bay stations showed the intermediate level in terms of species richness and diversity. On the basis of taxa composition and abundance in summer, the cluster analysis indicated that the study area was divided into live regions. The main factors that govern the polychaete distributions appeared to be the fresh water run-off and bottom sediment composition. However, a slight difference was observed in winter community, and changes in composition of the dominant species were found from Lagis bocki and Chone teres to Glycinde gurjanovae and Heteromastus filiformis. As a result, the broad scale reclamation and dredging activities may have played a role in changes of the polychaete community structure and the dominant species composition in Kwangyang Bay.

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A Study on the Pollution of Bisphenol A in Surface Sediment around Gwangyang Bay (광양만 주변해역의 표층퇴적물 중 Bisphenol A의 오염에 관한 연구)

  • Cho Hyeon-Seo;Kim Yong-Ok;Shin Tai-Sun;Horiguchi Toshihiro
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.7 no.2
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    • pp.104-110
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    • 2004
  • This study was carried out to survey the pollution of bisphenol A(BPA) and total organic carbon(TOC) in surface sediments around Gwangyang bay. BPA is suspected chemicals as endocrine disruption. Gwangyang bay Is located on the mid south coast of Korea. It is a semi-closed bay which Yeosu petrochemical industrial complex, POSCO(Pohang Steel Company) and Gwangyang container harbor are located. The surface sediments were collected at 15 stations with gravity corer at October, 1999, February, May and August, 2000. Also, the stream and intertidal sediment were collected at 5 sites at August, 2000. Concentrations of BPA in surface sediments were in the range of 0.46 to 24.59 ng/g dry wt.. Seasonal range(mean value) of BPA are 0.59 to 9.00(1.88) ng/g dry wt. at October, 0.99 to 2.97(1.57) ng/g dry wt. at February, 0.46 to 24.59(2.53)ng/g dry wt. at May and 0.54 to 2.46 (1.29)ng/g dry wt. at August. BPA was seasonally fluctuated, and the highest mean value and range were detected at May, 2000. BPA was highly distributed in the inner part of Kwangyang bay than Yosu sound. Concentrations of BPA in stream and intertidal sediments showed the highest value in downstream near Yochon petrochemical industrial complex and Yondung stream. It suggests that the source of BPA are industrial wastewater and municipal sewage. TOC in surface sediments were in the range of 0.09∼1.22%. There was no any correlation between the BPA and TOC.

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The Changing Patterns of Demand-Supply and Role of Mineral Resources in Economic Growth during Industrialization of the Republic of Korea (한국공업화과정(韓國工業化過程)에서의 광물자원(鑛物資源)의 수급구조변화(需給構造變化)와 경제성장(經濟成長)에 있어서의 역할(役割))

  • Yun, Suckew
    • Economic and Environmental Geology
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    • v.18 no.1
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    • pp.65-92
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    • 1985
  • A total of 12 mineral commodities significant in domestic output, economy and/or strategy of the Republic of Korea are chosen to examine the structural changes in production and demand-supply of these minerals during the last two decades of her industrialization. These include iron and manganese ores as the raw materials for iron and steel making, copper, zinc and tungsten ores among other non-ferrous metallic minerals, limestone (cement), kaolin, talc, pyrophyllite and graphite among other non-metallic minerals, and anthracite coal as the only domestic source of fossil energy. These are reviewed historically in time-series based on the statistical data which are tabulated and graphed in terms of domestic output, export, import, apparent demand-supply, its increasing rate, and self-sufficiency rate of each commodity. The increasing rates of demand-supply (IRDS) of some more important commodities are compared with those of Gross Domestic Production (GDP) and Economic Growth Rate (EGR) to evaluate how the IRDS contributed to the GDP and EGR. The major results revealed are as follows: Among the 12 commodities, the domestic output of 8 commodities appeared to have grown with steady upward trends: they are ores of lead, zinc and tungsten, limestone (cement), kaolin, talc, pyrophyllite and anthracite coal. Two commodities, ores of iron and copper, continued with unchanging or slightly declining trends and varied fluctuations, in spite of their cardinal importance to the heavy industry and strategy of Korea. The remaining two, graphite and manganese ore, have gradualy declined in domestic output in which the former has still enough resource potential but the latter has not and virtually ceased its domestic output. Trade patterns for mineral commodities in the Republic of Korea during the last two decades have changed greatly, being marked by a shift from mineral-exporting to mineral importing, mainly because of increasing consumption of mineral raw materials for industrialization rather than beceuse of decreasing output of domestic mineral commodities in quantity. In terms of trade patterns, the 12 commodities concerned in this study can be classified into the following four groups. The 1st group - ores of lead and tungsten have only been exported without imports. The 2nd group - amorphous graphite, and pyrophyllite have mainly been exported but partly been imported. The 3rd group - kaolin, talc and crystalline graphite have equally been exported and imported, but quantity of imports have rapidly been increased with time. The 4th group - ores of iron, manganese and zinc have shifted from exports to imports during the industrialization, particularly owing to the initiation of iron and steel making by the Pohang Iron and Steel Company in the middle 1970' s and the new establishment of the Onsan Zinc Refinery in the late 1970' s. All of the 12 commodities under considerations were far above 100% in self-sufficiency rate before or in the early 1960' s. Recently, however, most of them have been declined to below 100% except for those of limestone (cement) and pyrophyllite. It is particularly serious to identify that the self-sufficiency rates of the three important metallic minerals, iron, copper and manganese ores in 1982 appeared to be 5.1%, 0.5%, and 0.01%, respectively. The average self-sufficiency rate of the total domestic minerals produced in 1982 was 14.4% (in value) for that year. Mining industry appeared to be extremely high in its intermediate demand rate whereas its intermediate input rate to be quite low indicating that mineral raw materials have been exerted strong forward linkage effects upon the other industries rather than backward linkage effects. In comparing the curves of increasing rates of demand-supply of several major minerals - iron ore, manganese ore, copper ore, limestone (cement), kaolin, and anthracite coal - with those of Gross Domestic Production and Economic Growth Rate drawn on every graph, it is clearly shown that the curves of increasing rates of demand-supply comprise around 6 to 7 periods of cycles which roughly harmonious with those of the curves of GDP and EGR, except for the curve of anthracite coal of which the configuration seems to have resulted from the (artificial) government's mineral policy rather than from economic free market mechanism. The harmonic feature of these curves well suggests that the increasing rates of demand-supply of major minerals have been significantly contributed to the GDP and EGR. In addition, the wider amplitudes of the iron, manganese and copper curves than those of the limestone (cement) and kaolin curves indicate that the contribution of the former, metallic commodities, has been greater than that of the latter, non-metallic commodities.

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A Study on the Pollution of Polycyclic Aromatic Hydrocarbons(PAHs) in the Surface Sediments Around Gwangyang Bay (광양만 주변해역 표층퇴적물에서의 다환방향족탄화수소류(PAHs)의 오염에 관한 연구)

  • You, Young-Seok;Choi, Young-Chan;Cho, Hyeon-Seo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.13 no.1 s.28
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    • pp.9-20
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    • 2007
  • PAHs(Polycyclic Aromatic Hydrocarbons) are widespread contaminants in the marine environment. They are of mainly anthropogenic origin from urban runoff, oil spill and combustion of fossil fuels. Some PAHs are potentially carcinogenic and mutagenic to aquatic organism The contamination of PAHs in the coastal environments has not been well known yet in Korea. This study was carried out to survey the contamination of PAHs in sediments around Gwangyang bay. The Yeosu petrochemical industrial complex, POSCO(Pohang steel company) and Gwangyang container harbor are located around the bay. PAHs in sediment samples were extracted in soxhlet extractor and were identified and quantified by GC-MS(Gas Chromatography-Mass Spectrometry) TOC(Total Organic carbon) and textural parameters in sediment samples were also analyzed 13 species of PAHs were detected at all of the surface sediments. Total PAHs concentrations in the surface sediments ranged from 171.40 to $1013.54{\mu}g/kg$ dry wt.. In most of the surface sediments, Naphthalene was the highest in the range of 14.08 to $691.39{\mu}g/kg$ dry wt. and Anthracene was the lowest in the range of 0.49 to $22.66{\mu}g/kg$ dry wt.. The correlation coefficients between individual PAHs and Total PAHs in the surface sediments were relatively higher in the low molecular compounds such as Naphthalene and Phenanthrene. In the relationship of the P/A(Phenanthrene/Anthracene) ratio and F/P(Fluoranthene/Pyrene) ratio, P/A ratio was generally above 10 and F/P ratio was shown to be above 1 in all sediment samples. These data indicate that PAHs in sediments around Gwangyang bay seem to be of both pyrolytic and petrogenic origin. Total PAHs in the surface sediments were correlated with TOC and textural parameters. The values of PAHs in the surface and core sediments were lower than the biological effect guidelines.

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