• Journal of the Korean Geotechnical Society
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• v.36 no.9
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• pp.5-20
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• 2020

In 2017, after the Pohang earthquake, liquefaction phenomena were firstly observed after the observation of domestic earthquake by epicenter. In this study, various in-situ tests and laboratory tests were performed to determine the dynamic properties in (1) Songlim Park, (2) Heunghae-eup, Mangcheon-ri and (3) Heungan-ri, Pohang. As a site investigation, the standard penetration test (SPT), cone penetration test (CPT), multichannel analysis of surface wave (MASW), density logging, downhole test, and electrical resistivity survey were performed. In addition, cyclic triaxial test against sampled sand from site was also conducted. Based on the result, high ground water level and loose sand layer in shallow depth were observed for all sites. In addition, liquefaction resistance ratio of soil sampled from Songlim park was lower than those of Jumunjin sand, Toyoura sand, and Ottawa sand.

• Journal of the Korean Geotechnical Society
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• v.36 no.9
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• pp.21-32
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• 2020

In this study, series of cyclic triaxial tests and shear velocity measurement were conducted using Pohang sand, which was taken from liquefaction observed area, to verify the liquefaction characteristics of Pohang. The cyclic resistance ratio(CRR) was derived based on the test results. A specimen was reconstituted into 40% and 80% relative density conditions and then a series of cyclic triaxial tests and shear-wave velocity measurement were conducted. As a result, the effect of particle distribution and relative density to liquefaction resistance was verified. The liquefaction resistance of Pohang sand was evaluated by comparing with other liquefaction resistance of sands from previous research. In addition, the liquefaction resistance curve from field observation data was used to verify the reliability of results from this study by measured shear-wave velocity.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.213-220
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• 1990

The employees at the Pohang industrial area, where Clonarchis sinensis has been known to be endemic along the Hyungsan River, were examined parasitologically for clonorchiasis and a part of the infected cases were surveyed with a questionaire to outline the recent infection status of C. sinensis and epidemiological parameters in the area. Total of 3, 180 cases were tested by intra- dermal inoculation of C. sinensis antigen (Green Cross Co., Korea), and 834(26.2%) were found positive. Out of the positive cases, 598 were subjected to (ecal examination for helminth ova. The examination revealed 129(21.6%) ova Positive cases of C. sinensis, and Trichuris trichiura 1.7%, Ascaris lumbricoides 0.3%, and Metagonimus yokogawai 0.2%. The questionaire analysis showed some significant difFerences between the infected and non-infected(control) groups. The infected cases were less educated than the control, and they lived at the closer area to the river, and most of them lived there over 20 years. Also they preferred eating raw fresh water fish. Most of the detected cases were treated with prasiquantel and found negative for the eggs in 85.3% of them 1 year after the treatment. The present data reveal markedly decreased endemicity of clonorchiasis compared with previous prevalence rates but still clonorchiasis is endemic in the Hyungsan river basin. A comprehensive measure including case detection, treatment and education for parasite control should be applied to control clonorchiasis in such endemic areas.

• Journal of Korean Public Health Nursing
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• v.2 no.2
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• pp.45-61
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• 1988

Clonorchiasis should be realized as an important public health problems in Korea by their wide distribution, high prevalence rate and heavy infection intensity. This study was designed to obtain the infection rate, contributing factors as well as the behavior of infected persons among the factory workers in Pohang area where that parasite still remains as a problem. Study was undertaken from September '86 to October '87. Clonorchiasis skin test was performed for 3180 factory workers, and stools of skin test positive reactors were examined. Praziquantel was prescribed to stool examination positive persons for clonorchis sinensis ova. After one year. stool examination was repeated for them who received medicine. At the same time. a structured questionnaire was given and the results were analyzed and compared with control group. The results of this study are summarized as follows; 1. The infection rate of Clonorchis sinensis. 1) Clonorchiassis skin test positive rate was $26.2\%$ (834/3180). 2) Stool(Clonorchis sinensis ova) positive rate among skin test positive reactors was $21.6\%$ (129/598) All 129 infected persons were male. 2. Contributing factors of Clonorchis sinensis infection. 1) The chance of infection was higher in low-educated peple(p<0.01) 2) Stool(Clonorchis sinensis ova)positive rate was higher among the persons who reside near the riverside now(p<0.01), or among the persons who long history of riverside residence(p<0.01) 3) The infection rate was higher in thoes who like sliced raw fresh water fishes than in those who like cooked fishes(p<0.05). 4) Correct answering rate for questions about the cause and route of Clonorchis sinensis infection was low in infected persons. 5) The infection rate was lower among those who had experience of previous clonorchiasis test(p<0.01). 6) Family members of infected persons show higher rates of infection(p <0.01). 3. Treatment effect and compliance of infected person to treatment. 1) After one year, negative stool conversion rate was $85.4\%$. 2) $70.8\%$ of infected persons took the medicine; Only $3.1\%$ of them consulted to physician to know the medication effect; As many as $29.4\%$ of them continued to consume raw fresh water fishes. As a conclusion, City of Pohang area, Hyung San River in the center, is an endemic area of clonorchiasis. Current clonorchiasis control system seemed to be ineffective; many of the skin test positive group did not submitted their stool for examination; only $70.8\%$ of infected persons took the medicine even though the drugs were given free of charge; $29.4\%$ continued to consume raw fresh water fishes after taking medicine. Therefore. proper education program should be provided to improve the compliance to treatment. Follow-up for infected cases is mandatory to prevent waste of restricted budget.

• Journal of the Korean Institute of Navigation
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• v.10 no.2
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• pp.31-55
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• 1986

Generally, the development of shipping is characterized by the amount of traffic flow (traffic volume) and seaborne cargo in the sea. Movement of ships is an essential element of constructing the traffic flow which is represented the dynamic movement of ships in the sea, but on the other band the numbers of arriving and departing the port is the basic factor consisting of the static movement of ships. The amount of cargoes by coastal vessels and ocean trade vessels have increased tremendously with the great growth of the Korean economy these days. This increase of the seaborne cargoes has made the Korean coastal traffic flow so congested that this can be a cause of large pollution as well as great marine casualities such as a loss of human lives and properties . And also the future coastal traffic is expected to increase considerably according to our economic development and high dependence upon foreign trade. Under the circumstance, to devise the safety of coastal traffic flow and to take a proper step of a efficient navigation, there is a necessity for analyzing and surveying the coastal traffic trend and the characteristics of cargo movement. In order to grasp the dynamic movement of ships in the Korean coast, O/D analysis is executed. This paper aims to secure the basic data necessary for a comprehensive plan and estimation of vessel traffic management system for the enhancement of safety, order and efficiency of vessel traffic in the Korean coast. The analyzed results of the traffic flow and seaborne cargoes of the Korean coast are summarized as follows : 1) The congestion by the vessels occurred around the ports such as-in proportion of ship's number (proportion of tonnage) -Incheon 18.5%(14.8%), Pohang 5.9% (9.9%), Samil 5.2%(8.3%), Mokpo 8.6%(0.8%), Pusan 13.5%(36.4%), Ulsan 9.1%(16.2%). 2) It is found that the area adjacent to Incheon, Pusan, Ulsan, Channel of Hanryu and South-western area are heavily congested. 3) It is confirmed thatthe area adjacent to Incheon, Pusan, Ulsan, Channel of Hanryu and South-western area are heavily congested. 3) It is confirmed that the coastal vessels are main elements constituting the coastal traffic and that there are much traffic flow among five ports as following through the precise O/D analysis of ship's coastal movement. Incheon-Samil, Ulsan, Pusan, Jeju Pusan -Samil, Ulsan, Incheon, Jeju Pohang -Samil, Inchoen, Jeju Pohang -Samil, Incheon, Jeju Ulsan -Samil, Incheon, Jeju Samil -Ulsan, Pusan, Incheon 4) The amount of cargoes to abroad are in proportion about 81% of total and the amount of coastal cargoes are about 19%. Of those, cargoes in and out to Japan are about 26% and to South-east Asia are about 27%. 5) The chief items of foreign cargoes are oil(38.33%), iron ore(13.98%), bituminoous coal(12.74%), grain(8.02%), lumber(6.45%) in the import cargoes and steel material(21.96%), cement(17.16%), oil(6.81%), fertilizer(3.80%) in the export cargoes. 6) The 80.5% of total export cargoes and 92.4% of total import cargoes are flowed in five main ports. 7) The chief items of coastal cargoes are oil (42.45%), cement(16.86%), steel material (6.49%), anthracite(6.31%), mineral product(4.3%), grain, and fertilizer. Almost 92.24% of total import and export oil cargoes in Korea is loaded and unloaded at the port of Samil & Ulsan.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.559-569
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• 2022

This study investigated the acidification and mixing with seawater of groundwater, stream water, and reservoir water in the Hunghae area of Pohang City, as well as the source of water expelled to the stream by liquefaction induced by the Pohang earthquake on 15 November 2017. Geologically, the area consists of Tertiary sedimentary rocks. We collected six samples of groundwater, five of reservoir water, four of stream water, two of liquefaction water, and one of seawater to analyze the chemical composition and stable isotopes (𝛿D and 𝛿¹⁸O). Gogkang Stream flows eastward through the central part of the study area into the East Sea. The groundwater and reservoir water in the lower part of the stream are acidic (pH < 4), have a Ca(Mg)-SO₄ composition, and high concentrations of Al, Fe, and Mn, likely due to the oxidation of pyrite in Tertiary rocks. The groundwater in the upper part of the stream have a Ca(Na)-HCO₃(Cl) composition, indicating the mixing of seawater with the stream water. The 𝛿D and 𝛿¹⁸O isotope data indicate the isotopic enrichment of reservoir water by evaporation. Based on the chemical and isotopic data, it is inferred that the two samples of liquefaction water originated from alluvium water in a transition zone with stream water, and from deep and shallow groundwaters that has been infiltrated by seawater, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2719-2726
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• 2010

The purpose of this study was to investigate the scientific basic grounds for the assessment of health and environmental diseases resulting from air pollutants in Pohang. For this study, we investigated pollutants, weather characteristics and concentration distribution of fine particles ($PM_10$) yearly and each season, using data from Air Quality Monitoring Stations. The properties of concentration distribution and seasonal fluctuation of $PM_10$ were studied qualitatively and quantitatively using CALPUFF, air dispersion model. The average concentration of $PM_10$ for each season was spring($75.7{\mu}g/m^3$)>summer($56.8{\mu}g/m^3$)>winter($53.6{\mu}g/m^3$)>fall( $52.7{\mu}g/m^3$). In the case of spring, high concentrations appear due to the Asian dust frequently occurring. The contributions of $PM_10$ classified by the types of pollution source in Pohang were point source 62%>mobile source 33%>area source 5%. An important point is that 97% of emissions were produced from the iron manufacture in steel industry. Therefore, it is necessary to control the emission sources of pollutants and to construct an observation system at Pohang steel industrial complex from now on. It’s time to control the risk factors for health and environmental disease to protect the health of resident in Pohang and its neighboring areas.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.601-608
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• 2014

The purpose of this study was to explore the long-term variability of sea surface temperature (SST) and cluster analysis derived from in-situ data in the coastal oceanographic observation 8 stations (Sokcho, Jumunjin, Donghae, Jukbyeon, Pohang, Janggigab, Ulgi, Gampo) of the East Sea during 1971-2013. As a result of cluster analysis, SST variations in each area could be divided into two groups, which was a group A of Sokcho, Jumunjin, Donghae, and group B of Jukbyeon, Pohang, Janggigab, Ulgi, Gampo. The SST and SST anomalies at Sokcho, Jukbyeon, Pohang and Gampo during 1971-2013 showed the increase-trend with the variations of decadal-scale. Annual SST values also increased remarkably after 1988. The increases of SST for 43 years showed $2.26^{\circ}C$ at Sokcho, $1.99^{\circ}C$ at Jukbyeon, $1.11^{\circ}C$ at Pohang and $0.89^{\circ}C$ at Gampo. In particular, the SST variations of the northern areas were higher than those of southern areas. The seasonal SSTs increased the order of Sokcho-Jukbyeon-Pohang-Gampo in fall and winter and that of Jukbyeon-Sokcho-Pohang-Gampo in spring and summer.

• Economic and Environmental Geology
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• v.20 no.3
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• pp.159-168
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• 1987

Some physico-chemical properties such as surface area, moisture content, cation exchange capacity, swelling rate, pH, viscosity and liquid limit have been determined for evaluation of Cabentonite deposit occurring in four localities; Yonil, Gampo, Haseo and Pohang, in Gyeongsang-do. Montmorillonite contents can be derived from surface area measurement. Enhancement of liquid limit values and swelling volume were observed in the samples which had higher exchangeable Na ion and finer particle-size distribution. Identical results were observed even in the Na-exchanged samples. This suggests that aggregation effects have a great influence on physico-chemical properties. Aggregation of montmorillonite were controlled not only burial depth but also composition of exchangeable cation. Consequently, sample occurred in Yonil area where has the greatest burial depth in the area show somewhat lower physico-chemical properties than those of samples occurred in the other localities. However, the basic test applied in this study provides very useful preliminary information relating to its commercial potential.

• Korean Journal of Remote Sensing
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• v.5 no.2
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• pp.91-107
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• 1989

The purpose of this study is to investigate ways to use Landsat TM data for geological mapping and minieralized area detection. The study was carried out in Kyongju-Pohang area where toseki and bentonite mines are distributed. Rock samples of 18 granites, andesites, toseki, betonites, sedimentary rocks and altered rocks in the study area were collected for the study. The radiometric measurtment of the rock samples were carried out with a radiometer in the laboratory and in the field. The Landsat TM bands 2,3,4,5,7 were used for the measurement. The radiometric characteristics of the sample were mainly processed by the principal component analysis. It was found that the pricipal component analysis of the radiometric characteristics of geologic materials is very useful for the detection of the alteration of rocks and grade of mineral contents. It is expected that the technique can be used in the future for the efficient exploration of minerals in this country and abroad.