• Tuberculosis and Respiratory Diseases
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• v.40 no.6
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• pp.631-637
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• 1993

Background: In normal adults, ventilation is uneven and greater in the base than the apex of the lung in tidal volume breathing. However infants have fragile chest wall and reduced elastic recoil, resulting in easy closure of peripheral airways especially in the dependent portion of the lung. So ventilation in infants is greater in the apex than the base of the lung. We assumed that in adults whose closing volume is increased, dependent portion could be easily collapsed during tidal breathing and ventilation could be greater in the uppear than than the lower portion of the lung. Methods: We measured spirometry and closing volume(CV) in normal controls and in patients with chronic lung disease. Also we measured fractional distribution of ventilation at supine, left lateral and right lateral decubitus with $^{133}Xe$ ventilation scan in normal controls, patients with normal closing volume and patients with increased closing volume. Results: The subjects consisted of 7 normal controls(mean $age{\pm}SD$, $62.9{\pm}6.1$ years). 6 patients with normal CV($62.8{\pm}8.2$ years) and 7 patients with increased CV($63.0{\pm}15.3$ years). 1) Normal controls have mean(${\pm}SD$) FVC $104{\pm}11%$ of predicted value, $FEV_1\;120{\pm}16%,\;FEV_1/FVC\;112{\pm}5%$ and CV $86.9{\pm}12.5%$. Patients with normal CV have FVC $62{\pm}11%,\;FEV_1\;54{\pm}17%,\;FEV_1/FVC\;84{\pm}23%$ and CV $92.6{\pm}15.5%$. Patients with increased CV, have FVC $53{\pm}9%,\;FEV_1\;38{\pm}13,\;FEV_1/FVC\;69{\pm}16%$ and CV $176.1{\pm}36.6%$, CV was significantly different between two patient groups(p<0.02) 2). In normal controls mean fractional ventilation to left lung was $48.1{\pm}5.3%$ at supine, $54.1{\pm}9.8%$ at dependent and $40.9{\pm}6.5%$ at left uppermost position. In patients with normal CV mean fractional ventilation to left lung was $44.6{\pm}2.1%$ at supine, $59.7{\pm}5.6%$ at left dependent and $31.7{\pm}8.3%$ at left uppermost position. In patients with increased CV mean fractional ventilation to left lung was $48.7{\pm}4.5%$ at supine, $41.7{\pm}6.6%$ at left dependent and $60.9{\pm}15.7%$ at left uppermost position. In normal controls and patients with normal CV, ventilation to left lung at left dependent position tends to be higher than that at supine position but without statisitical significance and it was significantly lower at left uppermost than at left lung dependent position. In patients with increased CV, ventilation to left at left dependent position tends to be higher than that at supine position but without significance and it was significantly higher at left uppermost than that at left dependent position. Conclusion: These data suggest that in patients with increased CV ventilation to one side of lung could be higher at uppermost than at dependent position on lateral decubitus during tidal breathing and this fact should be taken into account in positioning of patients with unilateral lung disease.

• Tuberculosis and Respiratory Diseases
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• v.44 no.1
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• pp.136-145
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• 1997

Background : Tracheal Gas Insufflation (TGI) is one of the newer ancillary measures in mechanical ventilation employed to enhance carbon dioxide elimination. TGI exerts its effect through reduction of deadspace ventilation, but the factors determining its effect are not well studied yet. Method : The subjects were seven mechanically-ventilated patients ($58.8{\pm}10.6$ yrs) who showed increased physiologic deadspace greater than 60%. After 30 nun of stabilization with 100% oxygen on pressure control ventilation, continuous flow TGI was administered via the insufflation lumen of Hi-Lo Jet Tracheal Tube (Mallincrodt, USA) for 15 min at 3 L/min and 5 L/min each. Results : $PaCO_2$ was decreased ($51.4{\pm}17.6$ at baseline, $49.1{\pm}18.9$ at TGJ 3 L/min $45.0{\pm}14.9$ mm Hg at TGI 5 L/min, p=0.050), and pH was increased ($7.37{\pm}0.12$, $7.38{\pm}0.13$, $7.39{\pm}0.12$, respectively, p=0.037) while mixed expired $CO_2$ ($P_ECO_2$) was not changed significantly from baseline (p=0.336) by TGI. Physiologic deadspace(Vdphy) was decreased ($73.0{\pm}7.9$% at baseline, $69.8{\pm}10.0$% at TGI 3 L/min, and $67.1{\pm}10.1$% at TGI 5 L/min, p=0.015). $AaDO_2$(p=0.147), Vt(p=0.2140), Pmean(p=0.7788) and mean arterial pressure(p=0.4169) were not changed. The correlation between % maximal decrease of Vdphy were r=0.790 with the ratio of baseline Vdana/Vdphy(p=0.035) and r=-0.754 with baseline Vdalv(p=0.050). Conclusion: TGI was effective in reducing $PaCO_2$ and deadspace, and the deadspace-reducing effect was best correlated with baseline anatomic/physiologic deadspace ratio.

• Economic and Environmental Geology
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• v.34 no.5
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• pp.461-470
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• 2001

The Shihung mine was restored in the early 90's after abandonment for 20 yews since 1973. Although disposed mine tailings were removed and the site was replaced by an incineration plant, still some residual mine tailings remain in the places including the old mine tailing ditposal area and the adjacent agricultural area. These residual mine tailings are prone to impose an adverse impact on the soil and groundwater and needs investigation for the potential contamination. Mine tailing samples were collected from the old tailing disposal area and the iii paddy. The porewater from the mine tailing were extracted and analysed to investigate chemical changes along the reaction path. Batch leaching tests were also carried out in the laboratory to find any supporting evidence found in the field analysis. Evidence of elemental leaching was confirmed both by the mine tailing and the porewater chemistry in them. The element concentrations of Cu, Cd, Pb, Zn in the porewater exceed the standard for drinking water of Korean government and US EPA. Leaching of heavy metals from the mine tailing seem to be responsible for the contamination. In batch leaching test. heavy metals were either continuous1y released or declined rapidly. Combining the information with porewater variation with depths and the geochemical meodeling results, most of elements are controlled by dissolution and/or precipitation processes, with some solubility controlling solid phases (Cu, Pb, Fe and Zn). Batch leaching test conducted at fixed pH 4 showed much higher releases for the heavy metals up to 400 times (Zn) and this area is becoming more vulnerable to soil and groundwater pollution as precipitation pH shifts to acidic condition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.374-384
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• 1999

Benthic marine algal flora and community structure of Yongho-dong area in Pusan, Korea were investigated seasonally in intertidal and subtidal zones by a quadrat method along 5 transect lines from July 1996 to April 1997. In this area, a total of 99 species including 3 blue-green, 13 green, 26 brown and 57 red algae was found. Among them, 33 taxa, together with dominant Ulva pertusa and Corallina pilulifera, occurred throughout the year. Enteromorpha spp. and Ulva spp. vertically distributed in upper and middle zone, while Simphyocladia latiuscula, Chondria crassicaulis, Corallina pilulifera and Sargassum sup. in lower zones. Biomass per unit area exhibited a wide range of variation, from 1,241 g/$m^2$(spring) to 1,648 g/$m^2$(summer) in fresh weight. Maximum and minimum species diversity were recorded in spring and autumn, respectively. Results of the UPGAM cluster analysis suggest that the examined 5 sites can be divided into two groups, sites exposed to open sea (transects 1, 2, 3) and comparatively sheltered sites (transects 4, 5) faced with the Pusan Harbor. The former group is represented by large brown algae, Sargassum and Hizikia, while Ulva pertusa and Lomentaria species are mainly found in the latter group. A calcareous alga, Corallina pilulifera occurred dominantly in both groups throughout the year. In conclusion, number of species in this area was remarkably reduced as compared to the previous data. This result may suggest probably more change of algal vegetation in future, considering the physical and chemical pollutions loaded in the coastal marine environment of this area.

• Journal of Korea Soil Environment Society
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• v.2 no.3
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• pp.69-80
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• 1997

This investigation was conducted to provide information for characteristics of environmental pollution by the heavy metals from the abandoned gold mine in order to characterize the distribution patterns and environmental damages of the contaminants to the surrounding environment. Through analysis of CN, Cd, Cu, Pb, Zn, As, Cr, and Hg in a mine tailings, paddy soils, and stream sediments, the physico-chemical properties of the mine tailings and paddy soils were measured. The pH's were 5.4, 8.4 for the paddy soil and mine tailing, respectively. The maximum contents of CN, Pb, Cd, and As the in mine tailing were 99.98, 1,752.72, 31.88, and 298.50 mg/kg, respectively. The amounts of these ions were higher than the standard level of industrial area in Korea. The average content of CN and heavy metals in the paddy soils were higher than the background level of heavy metals in the unpolluted paddy soils around the mine. Especially, the contents of heavy metals in the paddy soils along the adjacent stream were higher compared to the paddy soil that was not influenced by the mine tailings. The contents of CN and heavy metals in the stream sediment close to the mine area were similar to those of the mine tailings, but decreased along the distance of the stream farther away from the tailings that was the source of these pollutants.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.79-87
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• 2017

In this paper, for 43 sites neighboring to western area of Gangwondo where disaster of debris flow occurred from 2006 to 2013, magnitude of debris flow was estimated from results of site investigation and correlation analysis between influencing factors to its magnitude was performed. Magnitude of channelized debris flow was found greater by 6.5 times of that of hill slope debris flow and approximately 5% of total volume was occurred at initiation part of channelized debris flow. As results of analyzing yield rate of debris flow, for channelized debris flow, yield rate values of $19m^3/m$ and $8m^3/m$ were obtained for total volume being over $10,000m^3/m$ as the large scale of debris flow and less than $10,000m^3/m$ respectively, and value of $5m^3/m$ was estimated for hill slope debris flow. As results of correlation analysis of influencing factors to magnitude of debris flow, runoff distance and erosion width were very highly correlated to its magnitude whereas average slope of basin and erosion depth showed relatively low correlation. In particular, value of erosion depth was in the range of 0.5-2.6 m, being similar range to the value proposed by Ikeya (1981). Triggering rainfall to debris flow such as continuous rainfall and maximum intensity of hour rainfall were analyzed to have low correlation with magnitude of debris flow.

• Korean Journal of Remote Sensing
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• v.33 no.3
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• pp.301-311
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• 2017

Aerosol optical properties as well as vertical location of layer can alter the radiative balance of the Earth by reflecting and absorbing solar radiation. In this study, radiative transfer model (RTM) and satellite-based analysis have been used to quantify the top-of-atmosphere (TOA) radiative effect of aerosol layers in the cloudy atmosphere of the northeast Asia. RTM simulation results show that the atmospheric warming effect of aerosols increases with their height in the presence of underlying cloud layer. This relationship is higher for stronger absorbing aerosols and higher surface albedo condition. Over study region ($20-50^{\circ}N$, $110-140^{\circ}E$) and aerosol event cases, it is possible to qualitatively identify absorbing aerosol effects in the presence of clouds by combining the UV Absorbing Aerosol Index (AAI) derived from Total Ozone Mapping Spectrometer (TOMS), cloud parameters derived from the Moderate Resolution Imaging Spectro-radiometer (MODIS), with TOA Upward Shortwave Flux (USF) from the Clouds and the Earth's Radiant Energy System (CERES). As the regional-mean radiative effect of aerosols, 6 - 26 % lower the USF between aerosols and cloud cover is taken into account. These results demonstrate the importance of estimation for the accurate quantification of aerosol's direct and indirect effect.

• Journal of Welding and Joining
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• v.17 no.2
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• pp.25-28
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• 1999

국내에 건설되어 거의 20∼30년 가동되고 있는 발전설비, 석유화학 플랜트 등 거대설비 기기의 건전성(integrity) 및 신뢰성 확보와 잔존수명 예측을 위해서는 구조물 내부 또는 표층부에 존재하는 결 함의 특성을 아는 것과 함께 그 재료의 특정 부위에 어느정도의 응력이나 변형이 있는가를 아는 것이 매우 중요하다. 일반적으로 강 용접부의 비파괴적 결함검출에는 주로 SV파(vertically shear wave)와 SH파(horizontally shear wave)라 불리는 횡파를 이용한 초음파사각탐상법이 실용화되어 이용되고 있다. 그러나 비파괴적인 방법에 의한 실험적인 잔류응력 측정, 변형해석법에는 전기 저항 및 자기 스트레인 게이지법, X선회절법, 광탄성법(photoelasticity), 모아레(Mohr's)법, 레이저스펙클(Laser speackle)법, 응 력도료법, Barkhausen Nosise법, Caustics법 등이 제시되어 있으나 그 유용성 면에서는 아직 해결되야할 문제가 많이 남아 있는 실정이다. 응력이나 변형을 해석하는 방법으로 이론적 방법, 계산적 방법 실험적 방법이 잇다. 이론적 방법에는 재료 역학적으로 취급하는 방법, 탄성론 등이 있고, 계산적인 방법에는 유한요소법이 있지만, 이론적 방법이나 계산적 방법만으로는 해석이 불가능한 경우가 많기 때문에 실험 적 방법이 필요하게 된다. 이 글에서는 파괴 시험 또는 다른 비파괴평가기술에 비해 간편한 측정, 높은 측정정도, 시험결과 도출의 신속성, 검사비용의 절감 등 많은 장점을 가지고 있고 실험적으로 유용성이 일부 검증되고 있는 음탄성법(Acoustoelasticity)에 의한 잔류응력 측정법에 관해 소개하고자 한다.TEX> mg/L(평균 49 mg/L)로 비교적 안정적인 처리효율을 보여주었다. 본 연구결과 HVC 공정은 화학약품 사용량의 절감 및 이에 따른 화학슬러지 발생량의 감소를 기대 할 수 있는 친환경기술로 유지관리비를 최소화할 수 있는 장점이 있었다. 않은 사람들 중 미래의 검진실행의지에 건강소식지가 영향을 미친 경우는 48.7%였다. 보건교육을 받은 후 유방암 자가검진 실천율은 사업군에서 53.9%로 받기 전의 27.3%보다 증가하였으나 대조군의 경우는 별 차이가 없었다. 연령별로는 60대가 가장 높았고 사업군에서 검진율의 증가분은 30대가 가장 컸다. 교육수준별로는 사업군은 고졸이, 대조군은 전문대졸이 가장 높았고 사업군에서 검진율의 증가분은 고졸에서 가장 컸다. 보건교육 후 유방암과 관련된 건강지식의 정도는 사업군이 3.7점으로 대조군보다 유의하게 높았으며, 유방암 자가검진법을 실천하는 사람들의 동기는 ‘일반 대중매체의 영향’이 가장 많았으며 건강소식지가 동기인 경우도 20.4%였다. 사업군에서 건강소식지가 유방암 자가검진법 실천에 영향을 미친 경우가 79.6%였으며 유방암 자가검진법에 관한 보건교육을 받고 실천하지 않은 사람들 중 미래의 실천의지에 건강소식지가 영향을 미친 경우는 43.6%였다. 이상의 소견에서 지역주민을 대상으로 인쇄매체를 통한 보건교육은 인쇄물만으로도 쉽게 실천 할 수 있는 유방암 자가검진법이 가장 효과적이었으며, 자궁암검진에 관해서도 검진을 받을 수 있도록 지역사회의 보건의료의 하부구조를 정비하여 제도적 장치를 마련하고 정보를 제공한다면 자궁암검진 실천율도 증가할 것이다.고 12.9% 의 발달율을 보여 유의적인 차이를 보이지 않았다. 이상의 결과로 보아 핵이식 수정란을 효율적으로 생산하기 위하여

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.221-221
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• 2019

기후변화로 인한 가뭄대비가 상시체제가 된 요즈음, 농업용수의 안정적인 공급을 위하여 가뭄 등의 비상시 지표수는 물론이고 지하수의 공급 가능량에 대해서도 국가적 관리가 필요한 실정이다. 지하수관리를 위해 국가 최상위 계획인'지하수관리기본계획(2012~2021)'이 수립되었고, 지하수의 장기적인 수량, 수질 관리를 위해 국가지하수관측망, 지역지하수관측망(보조지하수관측망), 수질측정망, 해수침투관측망 등 광역과 지역단위로 크게 나누어 지하수관측이 이루어지고 있다. 국가지하수관측망은 지하수법에 의거하여 전국의 주요지점(2016년 말 기준 412개소)에 관측소를 설치하여 수위 및 수질의 변동실태를 광역적으로 분석함이 목적이며, 보조지하수관측망은 국가지하수관측망과 연계하고 보완하기 위한 기능으로서, 지역별 주요 관측지점의 수위, 수질자료를 획득하며, 2018년 9월 현재 3,429개소가 설치되어있다. 본 연구에서는 지역지하수 관측망 중 경남밀양지역에 설치된 관측정 31개소에 대해 수위와 수질을 장기 분석하였다. 밀양지역의 보조지하수관측망 설치는 지하수관리계획의 하부계획인'경상남도 지하수관리계획(2015~2025)'에 의거 2012년에 6개소의 관측공이 설치를 시작으로, 2013년 7개소, 2014년 10개소, 2015년 8개소를 설치하여 총 31개소의 설치를 완료하였고, 2016년부터 2019년 현재까지 전체 관측정 31개소에 대하여 관측 운영 중이다. 본 연구에서는 2013년 1월~2019년 1월까지 지역의 누적강수량과 지하수위 및 수질변화를 관측하였다. 전 관측정에 대해 수위(GL.m), 수질(온도, EC)은 1시간 주기로 관측하였으며, 연 2회 생활용수 기준(19항목)의 수질검사를 실시하고, 지하수성분의 지질학적 기원분석을 위한 양음이온 분석을 연 1회 실시하였다. 관측정의 양수능력 변화관측을 위해 대수성 시험을 연 1회 실시하였고, 관측정의 특성상 장기간 미사용 관정이므로 최적의 상태유지를 위해 연1회 공내세척을 실시하였다. 또한, 관측정의 지형별 차이를 분석하기 위해 관측정의 설치위치를 산악, 강변, 기타 지역으로 구분하고, 각각의 대표관정에 대해 지형에 의한 서로 다른 영향을 분석하였고, 관측정의 심도별 변화를 알기위해 동일지역에 충적, 안반 관측정을 따로 설치하고 관측하여 지표수와 지하수의 심도별 영향의 차이를 분석하였다. 동일지역의 관측결과 평균 5m이하의 수위변화를 보이나, 5m 이상의 수위변동을 보이는 관측망은 15년 14개소 17년 19개소로 증가추세를 보이며, 이는 주로 밀집된 시설하우스 단지의 수막재배를 위한 겨울철 지하수 사용량 증가가 원인인 것으로 판단된다. 밀양지역은 강변지역에 밀집된 시설하우스단지의 동절기 수막재배를 위한 지하수 과다사용으로 수위급감 및 수량부족현상이 반복되고 있어, 예방과 대책강구를 위해 지표수의 함양과 지하수사용량의 상관관계 분석과 자료축적 및 추가연구를 위한 장기관측이 요구된다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.171-179
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• 2020

In this study, a local corrosion environment monitoring was conducted using steel box specimen fabricated to be the same as actual steel bridge members. The steel box specimen that obtained the same corrosion environment as a steel bridge was classified into the upper plate, bottom plate and web plate. Atmospheric corrosion monitoring sensors(ACM sensors) were installed in each corrosion monitoring member of a steel box specimen to measure the corrosion current and examine time of wetness for each monitoring member. The time of wetness and accumulated corrosion current of each monitoring member were calculated from the measured corrosion current using ACM sensors. The corrosion environment that appeared for each of the steel box members was evaluated from monitoring corrosion environment data as the corrosion current, time of wetness, mean corrosion depth of each monitoring member. Additionally, the atmospheric corrosion environment monitoring was also conducted to compare with the local corrosion environment of steel box members. From these local corrosion environment monitoring for the steel box specimen, the relationship between the relative corrosion environment and mean corrosion depth of each steel box member was examined.