• 대한기계학회논문집B
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• 제40권3호
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• pp.157-164
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• 2016

봉다발 유동에서 비틀림 혼합날개 지지격자의 대류열전달 성능을 실험적으로 평가하였다. 시험부는 $4{\times}4$ 정사각 배열의 봉다발로 제작하였고, 모의 봉다발에서 봉 중심 간 거리와 봉 외경의 비는 ~1.35이다. 대류열전달 성능 평가를 위해 혼합날개 지지격자 하류에서 봉 벽면 온도의 원주방향 및 축방향 분포를 측정하였다. 원주방향의 경우, 지지격자 하류에서 비틀림 혼합날개 끝이 향하는 벽면의 온도가 가장 낮게 나타났는데 이는 비틀림 혼합날개에 의해 왜곡된 유동 때문으로 판단된다. 반면, 축방향의 경우, 혼합날개 지지격자 근처에서 벽면의 온도가 크게 낮아졌는데, 이는 비틀림 혼합날개에 의해 대류열전달이 향상됨을 의미한다. 비틀림 혼합날개 지지격자에 의해 대류열전달 성능은 지지격자 상류에 비해 지지격자 근처 하류에서 ~35 % 향상되었고, 실험데이터를 기반으로 비틀림 혼합날개 지지격자에 대한 열전달 성능 예측 상관식을 제안하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권2호
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• pp.245-251
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• 2006

The aim of this study was to investigate the effects of caponization on the bone characteristics, biomechanical property and histology in Taiwan country chickens fed to market age of 26 wks. Male Taiwan country chickens $D{\times}L_2$ were caponized or sham-operated at 8 wks of age, and selected healthy sham-operated and completely caponized chickens (prominent degenerated comb) were selected at 16 wks old and fed to 26 wks old for the trials. Fifteen intact male chickens (Intact), sham-operated chickens (Sham) and caponized chickens (Capon) were assigned for trial 1, and sixteen Intact and Capon were assigned for trial 2. Results in trial 1 showed that the abdominal fat and relative abdominal fat weights of Capon were significantly heavier than Intact and Sham (p<0.05), while the tibia weight and relative weight were the lightest (p<0.05). The tibia breaking strength, bending moment and stress of Capon were the poorest among groups (p<0.05). The trial 2 produced the similar observation that Capon were significantly lighter than Intact (p<0.05) in the tibia weight, relative tibia weight and their biomechanical properties. On histological determinations, Capon showed a thinner cartilage end and fewer chondrocytes (about 50%) and trabecular, and bigger marrow cavity; while decreased hemopoietic cells number with increased adipocytes than Intact observed by H&E stain and at low magnification. At high magnification, Capon showed a decrease in the chondrocyte size by 33 to 50%, with smaller nucleus located near the cell membrane, and exhibited monocellular form chondrocytes. Capon also showed a less strongly acidic sulfated mucosubstance with weaker dyeing property within cartilage zone, and smaller chondrocytes size by Alcian blue stain.

• 대기
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• 제31권4호
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• pp.395-404
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• 2021

In order to investigate downslope windstorm by using more detailed observation, we observed 6 cases at 3 sites - Inje, Yongpyeong, and Bukgangneung - during "3-D Meteorological Observation Project in Yeongdong region of Gangwon province, South Korea in 2020." The results from analysis of the project data were as follows. First, AWS data showed that a subsidence inversion layer appeared in 800~700 hPa on the windward side and 900~850 hPa on the leeward side. Second, before strong wind occurred, the inversion layer had descended to about 880~800 hPa. Third, with mountain wave breaking, downslope wind was intensified at the height of 2~3 km above sea level. After the downslope wind began to descend, the subsidence inversion layer developed. When the subsidence inversion layer got close to the ground, wind peak occurred. In general, UM (Unified Model) GDAPS (Global Data Assimilation Prediction System) have had negative bias in wind speed around peak area of Taebaek mountain range, and positive bias in that of East Sea coast area. The stronger wind blew, the larger the gap between observed and predicted wind speed by GDAPS became. GDAPS predicted strong p-velocity at 0600 LST 25 Apr 2020 (4^th case) and weak p-velocity at 2100 LST 01 Jun 2020 (6^th case) on the lee-side of Taebaek mountain range near Yangyang. As hydraulic jump theory was proved, which is known as a mechanism of downslope windstorm in Yeongdong region, it was confirmed that there is a relationship between p-velocity of lee-side and wind speed of eastern slope of Taebaek mountain range.

• 지질공학
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• 제13권3호
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• pp.293-308
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• 2003

북한 지역 60km 하부 지각구조에 관한 새로운 결과를 토모그래피 방법으로 연구하였다. 한반도와 주변에서 얻어진 1013개의 P파와 S파 주행시간이 사용된다. 또한, 이 연구에서 토모그래피 알고리즘에 의해서 모든 지진의 진원이 재결정 된다. 속도구조의 파라미터화는 지진파 밀도에 따라 분포된 Node에 의해서 결정된다. 4개 Level의 120 Node가 각각 P파와 S파의 속도 구조에 적용된다. 연구 결과로 깊이 8Km의 량림 육괴의 깊이에서 P파와 S파 속도 이상변화는 각각 높고 낮게 나타났다. 그 반면에 평남분지의 P파와 S파 속도는 24km 깊이까지 모두 낮게 나타났다 그것은 량림 육괴는 지하수나 온천 등으로 포화 된 단층 및 파쇄대를 많이 갖고 있는 시생대-초기 하부 원생대육괴로 되어 있고, 반면에 평남분지의 평양-사리원 일대는 상부 원생대, 실루리안, 상부 고생대와 하부 중생대 기원의 퇴적층으로 채워진 내부 플렛트 폼 함몰로 되어 있음을 의미한다. 특히 백두산 하부 8, 16. 24km 깊이에서 높은 P파와 5파의 속도이상은 고결된 마그마 물체의 천부 도랑일지 모른다. 그러나 38km에서 낮은 P파와 S파 속도이상은 용융상태의 저속도 마그마방과 관련 된 것으로 본다. 우리는 또한 사리원을 포함한 옹진 분지에서 Moho불연속면이 약 55km임을 발견하였다. 백두산의 모호불연속면은 38km가량 된다. 특히 백두산 Moho에서 V/sub p//V/sub s/의 높은 비율은 지각과 맨틀 경계에서 용융물체가 있는것으로 간주된다. 또한 본 연구는 또한 량림육괴 순상지(Shield)의 끝 가장자리인 묘향산 지역 하부 40km에서 매운 높은 P파와 S파 속도 구조를 갖는 물체가 있음을 보여 주었다.

• 대한조선학회지
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• 제26권2호
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• pp.49-63
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• 1989

파랑표류력은 크기에 있어서는 2차항(2nd-order)의 힘으로, 파도의 주기로 나타나는 1차항(1st-order)의 파랑강제력에 비해 미미하나, 부유체 자체의 복원력이 없는 수평방향으로 작용하므로 부유체에 대변위 표류운동을 유발한다. 특히 장주기 표류력은 계류시스템에 장주기 대변위 공진응답을 야기시킬 수 있으므로 계류시스템의 설계 및 운용에 고려되어야 할 중요한 요소이다. 본 연구에서는 이론적 연구로서 개량된 Green 적분방정식을 이용하여 3차원 특이점을 분포하는 방법으로 near field법을 택하여 장주기 파랑표류력을 계산하였으며 계산결과는 Pinkster 및 Standing의 결과와 비교하였다. 비선형파의 산란효과 고려는 Pinkster의 근사방법을 따랐다. 실험적 연구로서 반잠수식 시추선의 1/60 모형에 대해 규칙파 및 불규칙파중 표류력계측시험을 수행하였으며 실험결과는 계산치와 비교되었다. 끝으로 계측시험에 있어 계류스프링의 영향 및 장주기 표류력 계측에 있어서 실험상 문제점을 논하였다.

• 한국환경보건학회지
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• 제48권4호
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• pp.227-235
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• 2022

Background: Abandoned metal mines are classified as vulnerable areas with the highest level of soil contamination among risk regions. People living near abandoned metal mines are at increased risk of exposure to toxic metals. Objectives: This study aimed to evaluate the correlation between soil contamination levels in areas around abandoned metal mine and the blood lead levels of local residents. Moreover, we assess the possibility of using soil contamination levels as a predictive indicator for human exposure level. Methods: Data from the Survey of Residents around Abandoned Metal Mines (2013~2017, n=4,421) and Investigation of Soil Pollution in Abandoned Metal Mines (2000~2011) were used. A random coefficient model was conducted for estimation of the lower level (micro data) of the local resident unit and the upper level (macro data) of the abandoned metal mine unit. Through a fitted model, the variation of blood lead levels among abandoned metal mines was confirmed and the effect of the operationally defined soil contamination level was estimated. Results: Among the total variation in blood lead levels, the variation between abandoned mines was 18.6%, and the variation determined by the upper-level factors such as soil contamination and water contamination was 8.1%, which was statistically significant respectively. There was also a statistically significant difference in the least square mean of blood lead concentration according to the level of soil contamination (p=0.047, low: 2.32 ㎍/dL, middle: 2.38 ㎍/dL, high: 2.59 ㎍/dL). Conclusions: The blood lead concentration of residents living near abandoned metal mines was significantly correlated with the level of soil contamination. Therefore, in biomonitoring for vulnerable areas, operationally defined soil contamination can be used as a predictor for human exposure level to hazardous substances and discrimination of high-risk abandoned metal mines.

• 한국환경복원기술학회지
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• 제16권1호
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• pp.181-191
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• 2013

The design process of ecological and environmental detention system located in the housing district of Sinjeong 3-jigu in Seoul are as follows. At stage one, a new dispersal detention was created in the neighborhood park located near the originally planned detention. From this, the amount of storage of this dispersal detention system was enlarged from $28,337m^3/d$, the initial storage amount, to $33,606m^3/d$ as the post storage amount, responsible to the amount of rainfall which happens every 100 years. In particular, the SSB (Sustainable Structured wetland Biotop) system, which was the New Excellent Technology verified by the Ministry of Environment (No. 258) was applied to enhance ecological functioning and water quality with the detention as a constructed wetland. At stage two, the treatment plans for non-point pollutant source occurred at the initial period of rain, flowing into the detention system were built for purifying the water of the retention pond at the base of the detentions, and the water-circulation system was designed at the dispersal detentions on the period of regular rainfalls. The non-point pollutant source flowing into detention site was calculated as $11,699m^3/d$ flowing down from seven small watersheds, which occurred at the initial period of rain. In particular the SSB systems improved the average efficiency of the water processing performance to BOD 60%, SS 90%, T-N 30%, T-P 60%. At stage three, the ecological network and biological diversity were strongly considered so that it brought the residents with amenity places. In particular, the dispersal detentions were successfully designed to restore the ecological habitat of endangered plant and animal species such as narrow-mouthed.

• 한국광물학회지
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• 제16권1호
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• pp.107-123
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• 2003

본 연구는 0가 철 (ZVI)의 설치위치와 전극의 배열에 따른 다양한 조합의 전기적 투수성 반응벽을 대상으로 트리클로로에틸렌의 탈염소화 반응에 의한 정화시 ZVI의 부식에 기인하는 광물상침전물에 대해 알아보고, 이에 대한 조절 요소를 알아보고자 한다. 광물학적 연구 결과, 지하수 유입부의 ZVI 시료는 상대적으로 많은 레피도크로사이트, 훼리하이드라이트 혹은 철 수산화물과 (phospho)siderite가 산출되는 반면, 용출부의 ZVI 시료는 아카가나이트, 자철석/마그헤마이트, 그리고 중간 산물인 green rust (CR) I 과 CR II가 산출되었다. 이러한 광물 조합의 변화는 용존 산소 및 pH의 상승에 주로 기인한 것으로 나타났다. 또한 전기적 투수성 반응벽 내에 산출되는 광물상 침전물들의 조절 요소들은 (1) pH, (2) 용존산소, (3) 철의 부식시 중간 산물, (4) 음이온 종류 등으로 밝혀졌다.

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1750-1759
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• 2020

The characterization of cytochrome P450 CYP125A13 from Streptomyces peucetius was conducted using cholesterol as the sole substrate. The in vitro enzymatic assay utilizing putidaredoxin and putidaredoxin reductase from Pseudomonas putida revealed that CYP125A13 bound cholesterol and hydroxylated it. The calculated K_D value, catalytic conversion rates, and Km value were 56.92 ± 11.28 μM, 1.95 nmol min^-1 nmol^-1, and 11.3 ± 2.8 μM, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis showed that carbon 27 of the cholesterol side-chain was hydroxylated, characterizing CYP125A13 as steroid C27-hydroxylase. The homology modeling and docking results also revealed the binding of cholesterol to the active site, facilitated by the hydrophobic amino acids and position of the C27-methyl group near heme. This orientation was favorable for the hydroxylation of the C27-methyl group, supporting the in vitro analysis. This was the first reported case of the hydroxylation of cholesterol at the C-27 position by Streptomyces P450. This study also established the catalytic function of CYP125A13 and provides a solid basis for further studies related to the catabolic potential of Streptomyces species.

• Natural Product Sciences
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• 제12권4호
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• pp.247-253
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• 2006

The antitumor activity of crude saponin mixture obtained from Luffa tuberosa (Roxb.) (Fam; Cucurbitaceae) hairy roots (CSLT) in mice transplanted with Ehrlich ascites carcinoma (EAC) was investigated. The EAC-bearing mice receiving 150 and $300{\mu}g/kg$ body weight, (i.p) of CSLT have shown a dose dependent elevation in tumor-tree survival and a highest number of survivors were observed after administration of CSLT $(300{\mu}g/kg)$, which was considered as an optimum dose for its antineoplastic action. The mean survival time (MST) for this dose was approximately $47.1{\pm}0.74d$, when compared with $19.0{\pm}0.36d$ of untreated control. Administration of $300{\mu}g/kg$ CSLT resulted in 130% long-term increased survival time. The measurement of body weight, tumor volume, packed cell volume, viable and non-viable count indicated the efficacy of CSLT in tumor-bearing mice, there was a significant recovery in hematological profiles, and there was depletion in lipid peroxidation levels, and the antioxidant enzyme activities such as GSH, SOD and CAT were restored to near the normal levels. The CSLT was found to be devoid of conspicuous short-term toxicity in the mice when animals were intraperitoneally injected with 250, 500, 750 and $1000{\mu}g/kg$ bodyweight. The treated mice showed conspicuous toxic symptoms only at a dose of $1500{\mu}g/kg$. Mortality of the animals was monitored up to 14 d post drug treatment, $1/7^{th}$ of the $LD_{50}$ dose has been considered for the optimal antineoplastic activity.