3D-FEMWATER 모델을 이용한 대창지역의 해수침투 범위추정

김경호,박재성,이호충,연주흠,Kim Kyoung-Ho,Park Jae-Sung,Lee Ho-Jin,Youn Ju-Heum 한국농공학회 2005 한국농공학회논문집 Vol.47 No.5

The present study examined the 3 dimensional space distribution characteristics of sea water intrusion using data available from previous observations. For this study, we used 3D FEMWATER, which is a 3 dimensional finite element model. The target area was around Daechang-ri, Gimje-si, Jeollabuk-do. The area is relatively easy to formulate a conceptual model and has observation wells in operation for surveying sea water intrusion. Considering the uncertainty of numerical simulation, we analyzed sensitivity to hydraulic conductivity, which has a relatively higher effect. According to the result of the analysis, the variation of TDS concentration had an error range of $-1,336{\~}+107 mg/{\iota}$. Taking note that the survey data from observation wells were collected when the boundary between fresh water and sea water in the aquifer was in equilibrium, we set the range of time for numerical simulation and estimated the spatial distribution of TDS concentration as the range of sea water intrusion. According to the result of estimation, the spatial distribution of TDS concentration calculated when 1,440 days were simulated was taken as the range of sea water intrusion. Using the result of calculation, we can draw not only vertical views for a certain section but also horizontal views of different depth. These views will be greatly helpful in understanding the spatial distribution of the range of sea water intrusion. In addition, the result of this study can be used rationally in proposing an optimal quantity of water pumping through investigating the moving route of sea water intrusion over time in order to prevent excessive water pumping and to maintain an optimal number of water pumping wells per interval.

쇄파후(碎波後) 발생(發生)하는 연안류(沿岸流)의 유속분포(流速分布)에 관한 연구(?究)

김경호,구봉근,Kim, Kyoung Ho,Koo, Bong Kuen 대한토목학회 1986 대한토목학회논문집 Vol.6 No.4

This study aims at the elucidation of the distribution of longshore currents after wave breaking. Longshore currents have relations to the beach process and dispersion of contaminants in the nearshore region, thus the understanding of its. mechanism is very important. In the present study, using the electromagnetic current meter, the water particle velocity is measured in the 3-dimensional wave field and Eulerian mean velocity is obtained. At the same time, from the dispersion of tracer, the Lagrangian mean velocity is also obtained. It is observed that the longshore currents were confined within the surf zone and the maximum value of them exists in the surf zone. The longshore currents were considered to be constant toward the depth and we obtained the similar distribution of longshore currents between the measured value and the theoretical ones by Longuet-Higgins model. 연안류(沿岸流)는 연안표사(沿岸漂砂) 해안침식(海岸侵食) 또는 항만매몰(港灣埋沒)외 원인(原因)이 되기도 하며, 연안역(沿岸域)의 물질확산(物質擴散)의 외력(外力)으로 작용(作用)하기 때문에, 그 현상(現象)의 이해(理解) 및 구명(究明)은 공학적(工學的)으로 갖는다. 본(本) 연구(硏究)에서는 실험(實驗)을 통해서 연안류(沿岸流)의 분포특성(分布特性)을 고찰(考察)하고, 실험결과(實驗結果)를 Longuet-Higgins model에 의한 계산치(計算値)와 비교(比較) 검토(檢討)하였다. 일반적(一般的)으로 연안류(沿岸流)는 쇄파대내(碎波帶內)에 국한(局限)되어 분포(分布)하며, 쇄파대외(碎波帶外)에서는 매우 미약(微弱)함을 보였다. 연안류(沿岸流) 수심방향(水深方向)으로의 분포(分布)는 거의 일정(一定)하였으며, 실험치(實驗値)와 계산치(計算値)는 최대치(最大値) 부근(附近)을 제외하고, N=0.05 일 경우 좋은 일치(一致)를 보이고 있다.

4개의 칩이 적층된 FBGA 패키지의 휨 현상 및 응력 특성에 관한 연구

김경호,이혁,정진욱,김주형,좌성훈,Kim, Kyoung-Ho,Lee, Hyouk,Jeong, Jin-Wook,Kim, Ju-Hyung,Choa, Sung-Hoon 한국마이크로전자및패키징학회 2012 마이크로전자 및 패키징학회지 Vol.19 No.2

Semiconductor packages are increasingly moving toward miniaturization, lighter and multi-functions for mobile application, which requires highly integrated multi-stack package. To meet the industrial demand, the package and silicon chip become thinner, and ultra-thin packages will show serious reliability problems such as warpage, crack and other failures. These problems are mainly caused by the mismatch of various package materials and geometric dimensions. In this study we perform the numerical analysis of the warpage deformation and thermal stress of 4-layer stacked FBGA package after EMC molding and reflow process, respectively. After EMC molding and reflow process, the package exhibits the different warpage characteristics due to the temperature-dependent material properties. Key material properties which affect the warpage of package are investigated such as the elastic moduli and CTEs of EMC and PCB. It is found that CTE of EMC material is the dominant factor which controls the warpage. The results of RSM optimization of the material properties demonstrate that warpage can be reduced by $28{\mu}m$. As the silicon die becomes thinner, the maximum stress of each die is increased. In particular, the stress of the top die is substantially increased at the outer edge of the die. This stress concentration will lead to the failure of the package. Therefore, proper selection of package material and structural design are essential for the ultra-thin die packages. 최근 모바일 기기에 적용되는 반도체 패키지는 초소형, 초박형 및 다기능을 요구하고 있기 때문에 다양한 실리콘 칩들이 다층으로 수직 적층된 패키지의 개발이 필요하다. 패키지 및 실리콘 칩의 두께가 계속 얇아지면서 휨 현상, 크랙 및 여러 다른 형태의 파괴가 발생될 가능성이 많다. 이러한 문제는 패키지 재료들의 열팽창계수의 차 및 패키지의 구조적인 설계로 인하여 발생된다. 본 연구에서는 4층으로 적층된 FBGA 패키지의 휨 현상 및 응력을 수치해석을 통하여 상온과 리플로우 온도 조건에서 각각 분석하였다. 상온에서 가장 적은 휨을 보여준 경우가 리플로우 공정 조건에서는 오히려 가장 큰 휨을 보여 주고 있다. 본 연구의 물성 조건에서 패키지의 휨에 가장 큰 영향을 미치는 인자는 EMC의 열팽창계수, EMC의 탄성계수, 다이의 두께, PCB의 열팽창계수 순이었다. 휨을 최소화하기 위하여 패키지 재료들의 물성들을 RMS 기법으로 최적화한 결과 패키지의 휨을 약 $28{\mu}m$ 감소시킬 수 있었다. 다이의 두께가 얇아지게 되면 다이의 최대 응력은 증가한다. 특히 최상부에 위치한 다이의 끝 부분에서 응력이 급격히 증가하기 시작한다. 이러한 응력의 급격한 변화 및 응력 집중은 실리콘 다이의 파괴를 유발시킬 가능성이 많다. 따라서 다이의 두께가 얇아질수록 적절한 재료의 선택 및 구조 설계가 중요함을 알 수 있다.

시로코 홴 성능 및 공력 소음 예측에 관한 연구

김경호,박계찬,이승배,Kim, Kyoung-Ho,Park, Kye-Chan,Lee, Seungbae 한국유체기계학회 1999 한국유체기계학회 논문집 Vol.2 No.4

The prediction method of the performance and aerodynamic noise from a sirocco fan was developed and compared with measured data. To predict the performance of the sirocco fan, the well-known slip coefficients and various loss models were tested and applied to forward curved sirocco impellers. Using loss models proposed for both impeller and casing, the predicted performance characteristics were in good agreement with measured ones by an ANSI test plenum. Various scaling models for aerodynamic noise from the sirocco fan were evaluated and tested against measured power levels in terms of flow coefficient. It was shown that the turbulent broadband sound power from the sirocco fan can be modeled successfully by trailing edge noise.

국내 심부 암반지하수에서의 고농도 불소 산출과 관련된 수리지구화학 진화

김경호,윤성택,채기탁,김성용,권장순,고용권,Kim Kyoung-Ho,Yun Seong-Taek,Chae Gi-Tak,Kim Seong-Yong,Kwon Jang-Soon,Koh Yong-Kwon 대한자원환경지질학회 2006 자원환경지질 Vol.39 No.1

국내 심부 암반지하수에서의 고농도 불소의 산출을 지배하는 지질 및 수리지구화학적 환경을 이해하고자, 온천 개발 목적으로 착정한 심부지하수 관정(평균 심도 약 600m)에서 취득된 총 367개의 지하수 분석 자료에 대하여 지구화학적 고찰을 수행하였다. 이들 지하수에서의 불소 농도는 매우 높아 평균 5.65mg/L에 이르며, 특히 연구 대상 지하수 중 $72\%$에서 먹는 물 수질기준(1.5mg/L)을 초과하였다. 불소 함량은 일차적으로 지질 조건의 지배를 강하게 나타냄을 확인하였는데 가장 높은 농도는 화강암류 및 화강편마암 지역에서 산출되는 반면 화산암 및 퇴적암 지역에서는 가장 낮았다. 지하수의 수리지구화학상과 관련하여 보면, 중성 내지 약알칼리성인 $Ca-HCO_3$형 지하수에 비하여 알칼리성의 $Na-HCO_3$형 지하수가 현저히 높은 불소 함량을 나타내었다. 화강암류 및 화강편마암 지역에서 지하수의 심부 순환에 수반되는 장기간의 물-암석 반응이 고농도 불소 산출의 가장 중요한 이유로 생각된다. 방해석 침전 또는 양이온교환에 의한 Ca 이온의 감소, 그리고 뒤따라 발생하는 사장석과 불소 함유 수산화광물(특히 흑운모)의 용해로 특징되는 일련의 수리지구화학 반응이 이러한 환경 하에서의 고불소 지하수 생성의 원인으로 해석된다. 따라서 불소과다에 의한 물 공급 문제의 발생 가능성은 높은 pH 및 매우 높은 Na/Ca농도비를 나타내는 화강암류 및 화강편마암 지역의 지하수에서 가장 높다고 볼 수 있다 To understand the geologic and hydrogeochemical controls on the occurrence of high fluoride concentrations in bedrock groundwaters of South Korea, we examined a total of 367 hydrochemistry data obtained from deep groundwater wells (avg. depth=600 m) that were drilled fur exploitation of hot springs. The fluoride concentrations were generally very high (avg. 5.65mg/L) and exceeded the Drinking Water Standard (1.5 mg/L) in $72\%$ of the samples. A significant geologic control of fluoride concentrations was observed: the highest concentrations occur in the areas of granitoids and granitic gneiss, while the lowest concentrations in the areas of volcanic and sedimentary rocks. In relation to the hydrochemical facies, alkaline $Na-HCO_3$ type waters had remarkably higher F concentrations than circum-neutral to slightly alkaline $Ca-HCO_3$ type waters. The prolonged water-rock interaction occurring during the deep circulation of groundwater in the areas of granitoids and granitic gneiss is considered most important for the generation of high F concentrations. Under such condition, fluoride-rich groundwaters are likely formed through hydrogeochemical processes consisting of the removal of Ca from groundwater via calcite precipitation and/or cation exchange and the successive dissolution of plagioclase and F-bearing hydroxyl minerals (esp. biotite). Thus, groundwaters with high pH and very high Na/Ca ratio within granitoids and granitic gneiss are likely most vulnerable to the water supply problem related to enriched fluorine.

미스트화학기상증착시스템의 전구체 수용액 혼합비 조절을 통한 (Al_xGa_1-x)₂O₃ 에피박막의 밴드갭 특성 제어 연구

김경호,신윤지,정성민,배시영,Kim, Kyoung-Ho,Shin, Yun-Ji,Jeong, Seong-Min,Bae, Si-Young 한국전기전자재료학회 2019 전기전자재료학회논문지 Vol.32 No.6

We investigated the growth of $(Al_xGa_{1-x})_2O_3$ thin films on c-plane sapphire substrates that were grown by mist chemical vapor deposition (mist CVD). The precursor solution was prepared by mixing and dissolving source materials such as gallium acetylacetonate and aluminum acetylacetonate in deionized water. The [Al]/[Ga] mixing ratio (MR) of the precursor solution was adjusted in the range of 0~4.0. The Al contents of $(Al_xGa_{1-x})_2O_3$ thin films were increased from 8 to 13% with the increase of the MR of Al. As a result, the optical bandgap of the grown thin films changed from 5.18 to 5.38 eV. Therefore, it was determined that the optical bandgap of grown $(Al_xGa_{1-x})_2O_3$ thin films could be effectively engineered by controlling Al content.

남자 비행청소년의 성문화에 관한 연구

김경호(Kyoung Ho Kim) 한국정신건강사회복지학회 2005 정신보건과 사회사업 Vol.19 No.-

한국수산금융정책의 방향

김경호(Kyoung Ho Kim) 한국수산경영학회 1998 수산경영론집 Vol.29 No.1

This paper focuses on the history of fisheries finance in Korea, especially the role of fisheries finance after the establishments of korean fisheries cooperative. We can say that our fisheries was influenced greatly by the fisheries finance. It may be proved by the facts that our fisheries experienced a great growth right after the input of big fisheries finance. The products of fisheries has increased from 1962 to now. And the structure of the fisheries has improved. But there were unequal development in the each sectors of fisheries. Though the deep sea fishery and farming has developed faster, coastal fishing that are absorbing nearly 90% of fisheries population has stagnated. Of course it was because of unequal financial assistance by Authority So to improve fisheries evenly, it is very important to overcome various problems that have encountered including the new circumstances like the WTO. For this, lots of steps should be taken. They can be summarized as follows. 1) It may be inevitable to see a rising costs in the deep sea fishery because of the declaration of EEZ by almost every nation. 2) So coastal fishing should be getting more important. It is necessary to improve the structure of coastal fishing and we should be ready to prepare various alternatives for self - sustained growth in coastal fishing. 3) Especially fisheries finance should play a more active role. 4) Self-sustainable growth means a fishery with full compatability. For full compatability it is necessary to give financial supports for making fishing ground and equipping anti - pollution system and labour saving apparatus etc. 5) Also to raise the ratio of self - support in fisheries products it is necessary to give financial support to traditional financial system. 6) Moreover it is necessary to guide utilization of finance supplied. For this the committee that is consists of professional people in that field is strongly asked. This committee should be entitled to decide and coordinate the selection of projects, allocation of finance, method of utilization and evaluation of projects etc.

송풍기의 소음레벨 측정방법

김경호(Kyoung-Ho Kim),이승배(Seungbae Lee) 한국소음진동공학회 2000 한국소음진동공학회 학술대회논문집 Vol.2000 No.1

결핵 환자에서 고혈압으로 발현된 타카야수동맥염

김경호 ( Kyung Ho Kim ),신재경 ( Jae Kyoung Shin ),김선원 ( Sunwon Kim ),조우희 ( Woo Hee Cho ),김성순 ( Sung Soon Kim ) 대한내과학회 2017 대한내과학회지 Vol.92 No.1

Takayasu`s arteritis (TA) is an inflammatory disease involving large arteries and their branches. The etiology of TA is unknown, but infectious agents and genetic factors play a significant role in its pathogenesis. A relationship between TA and Mycobacterium tuberculosis infection has been suggested, since both diseases have similar chronic inflammatory lesions and the presence of occasional granulomas in arterial walls. Patients with TA have an increased immune response to Mycobacterium tuberculosis antigens, suggesting a role for this organism in the immunopathogenesis of the disease. Herein, we present a case of TA with active pulmonary tuberculosis in a Korean patient. A 21-year-old male presented with hypertension and active pulmonary tuberculosis. TA invading the renal artery was diagnosed while evaluating hypertension. The patient was treated with prednisolone, methotrexate, anti- hypertensive medications, and anti-tuberculosis medications. (Korean J Med 2017;92:66-69)