• Title/Summary/Keyword: Dam hun

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A Clinical Report on The Atrophic Acne Scar with Subcision (코라테라피(절개침)을 이용한 위축성 여드름 흉터의 치험례)

  • Baek, Sang-Chul;Hong, Mu-Suk;JeGal, Hun;Jin, Yong-Hee;Joo, Tae-Min;Lee, Sang-Jun;Jo, Eun-Hee;Park, Min-Cheol
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.25 no.4
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    • pp.80-88
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    • 2012
  • Background and Objective : Atrophic scars are the most common complication of acne. Many modalities are proposed but each does not yield satisfactory clinical outcomes. Among therapeutic modalities of acne scars, subcision is a simple, safe procedure with a different and basic mechanism for correcting atrophic and depressed scars. However, there are few reports about such procedure. This study performed to evaluate the effect of subcision treatment on atrophic acne scar. Methods : Five patients with atrophic acne scars of various types(rolling, superficial and deep boxcar, pitted and icepick) were treated by superficial dermal undermining with 25~27 gauge needles. We used GASC(Global Acne Scarring Classification). Satisfaction degree was asked from the patients. Results and Conclusions : After observing patients satisfaction, comparing case photos and GASC, it can be considered that subcision treatment brings great results when performed on atrophic post acne scars.

Assessment of Pollution Characteristics of Surface Sediments from Andong Lake(I): Studies on Characteristics of Pollution of Sediments from Andong Dam (안동댐 퇴적물의 오염도 평가(I): 안동댐 퇴적물의 오염 특성 연구)

  • Kim, Young Hun;Park, Jae Chung;Shin, Tae Cheon;Kim, Jeong Jin
    • Korean Journal of Mineralogy and Petrology
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    • v.33 no.4
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    • pp.377-389
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    • 2020
  • In this study, pollution characteristics were investigated for the Andong Dam sediments in the Nakdong River. Sediment samples were collected from the middle, left, and right points of the lake up to 40km upstream of the Andong Dam at intervals of about 5km by stratification and turnover period. In the case of nutrients and total organics such as loss of ignition, total nitrogen, and phosphorus, the degree of contamination is low, but heavy metals of arsenic and cadmium is very high. The contamination level of sediments in the dam area is higher than that of the branch of river and the control group, and concentration of chromium, copper, and lead are higher in the stratification period, and that of zinc is higher in turnover period. Arsenic, cadmium, manganese, and zinc showed contamination variation between upstream and downstream but chromium, copper, mercury, iron and lead didn't show the variation.

Simulation of Turbid Water According to Watershed Runoff and Withdrawal Type in a Constructing Reservoir (건설 예정인 댐에서 유역유출과 취수형태에 따른 탁수의 거동 예측)

  • Park, Jae-Chung;Choi, Jae-Hun;Song, Young-Il;Yu, Kyung-Mi;Kang, Bo-Seung;Song, Sang-Jin
    • Journal of Environmental Impact Assessment
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    • v.19 no.3
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    • pp.247-257
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    • 2010
  • Watershed runoff and turbid water dynamics were simulated in the Youngju Dam, being constructed. The runoff flow and suspended solids were simulated and then thermal stratification and turbid water current in the reservoir were predicted by HSPF and CE-QUAL-W2 model, respectively. Considering selective withdrawal, we hypothesized 3 withdrawal types from the dam, i.e. surface layer, middle layer and the lowest layer. The maximum concentration of SS was 400mg/L in reservoir and it was decreased by the withdrawal. The inflowed turbid water fell to 30 NTU after 12 days regardless of the withdrawal types, but the surface layer withdrawal was a better type at turbid water discharge than the others. In current environmental impact assessment(EIA), we concluded that runoff and reservoir water quality predicted by HSPF and CE-QUAL-W2 was desirable, and appropriate parameters were selected by continous monitoring after EIA.

A Lubrication Performance Analysis of Mechanical Face Seals Using Galerkin Finite Element Method (갤러킨 유한요소해석법을 이용한 미케니컬 페이스 실의 윤활성능해석)

  • Choe, Byeong-Ryeol;Lee, An-Seong;Choe, Dong-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.6
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    • pp.916-922
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    • 2001
  • A mechanical face seal is a tribo-element intended to control leakage of working fluid at the interface between a rotating shaft and its housing. Leakage of working fluid decreases drastically as the clearance of the mating seal faces gets smaller. But the very small seal clearance results in an increased reduction of seal life because of high wear and heat generation. Therefore, in the design of mechanical face seals a compromise between low leakage and acceptable seal life is important, and it presents a difficult and practical design problem. A fluid film or sealing dam geometry of the seal clearance affects seal lubrication performance very much, and thereby it is one of the main design considerations. In this study the Reynolds equation for the sealing dam of mechanical face seals is numerically analyzed, using the Galerkin finite element method, which is readily applied to various seal geometries. Film pressures of the sealing dam are analyzed, including the effects of the seal face coning and tilt. Then, lubrication performances of the seals, such as opening forces, restoring moments, leakage, and dynamic coefficients, are calculated, and they are compared to the results obtained by the narrow seal approximation.

Kinematic Control of Redundant Robots in the Constrained Environment and Its Applicaiton to a Nozzle Dam Installation/Detachment Task in Nuclear Power Plants (구속된 환경에서의 여유자유도 로봇의 기구학적 제어와 원자력 발전소 노즐댐 장 /탈착작업에의 적용)

  • Park, Ki-Cheol;Chang, Pyung-Hun;Kim, Seung-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.12
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    • pp.3871-3882
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    • 1996
  • In this paper, a closed-form formulation for inverse kinematics of robot manipulators with kinematic redundancy under the constrained environment has been derived using the Kuhn-Tucker condition, the extended Lagrange multiplier method and the working set method. The proposed algorithm satisfies the necessaryand sufficient conditions for optimization subject to equality and inequality constraints. In addition, computationally efficient kinematic control methods have been proposed using differential kinemetics and gradient projection mehtod. The effectiveness of the proposed methods has been demonstrated with a 4-dof planar robot, and then a 7-dof spatial robot as a practical application to the nozzle dam task in the Nuclear Power Plant.

Use of a Rubber Dam System in Consideration of Climate Change (기후변화 대응을 위한 고무보시스템 선정 방안 연구)

  • Hwang, Yun-Bin;Park, Ki-Hak;Kim, Seo-Hyun;Kang, Hun;Kim, Ji-ho
    • Journal of Climate Change Research
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    • v.9 no.4
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    • pp.319-324
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    • 2018
  • Due to climate change, water shortages and water-related disasters will be serious. Since the damage and frequency of drought are increasing, the importance of water resource management technology is increasing. In this study, we analyzed the amount of greenhouse gas and the environmental impact caused by the production and operation system technologies of movable weir among various water resource management technologies. The research subjects were air inflatable rubber dams widely used in rivers and upright type rubber dams, which are an improvement on the existing rubber type. Each type of dam was studied at sizes of $1,500H{\times}10,000L\;mm$ and $3,000H{\times}20,000L\;mm$, and the two types and two sizes were compared and analyzed. Using life cycle assessment, we examined the environmental impacts using the amount of electricity required for operation and the discretionary amount required for production. In the '$1,500H{\times}10,000L$' dams, the global warming indexes were $9.35E+04kg\;CO_2-eq$. for upright type and $7.36E+04kg\;CO_2-eq$. for inflatable type. At size of '$3,000H{\times}20,000L$' the global warming indexes were $9.09E+05kg\;CO_2-eq$. for upright type and $1.07E+06kg\;CO_2-eq$. for inflatable type. Analysis of the life cycle environmental impact showed that the environmental impact of the air inflatable rubber dam was reduced by 39.8% at '$1,500H{\times}10,000L$' compared to the larger size. At the larger '$3,000H{\times}20,000L$' size, the upright dam showed a 10.1% smaller impact than the air inflatable rubber dam. Selection of water resource management system should consider climate change, not only management purpose and cost. Additional studies and improvements on rubber dam systems should be made.

Study on Analysis of Suitable Site for Development of Floating Photovoltaic System (수상태양광 발전시스템 개발을 위한 적지조사에 관한 연구)

  • Lee, Sung-Hun;Lee, Nam-Hyung;Choi, Hyeong-Cheol;Kim, Jin-O
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.7
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    • pp.30-38
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    • 2012
  • Recently, interests in renewable energy have gradually increased. Photovoltaic system of various renewable energy is the most interest in power sources. Nowadays, the market of photovoltaic system is expected to be expanded due to the introduction of RPS(Renewable Portfolio Standard). Floating photovoltaic system is a new power system using the water surface above the dam and reservoir water. Floating photovoltaic system is different from the traditional approach to the development of solar power system causing problems such as environmental degradation. This paper investigates the analysis methods of suitable site for the development of floating photovoltaic system. The A,B,C as the optimal candidates were selected in hap cheon dam. The C is the best suitable site in A,B,C considering the expected power generation. Applied methods have effectively done to develop floated photovoltaic system.