• 한국결정성장학회지
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• 제10권2호
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• pp.91-95
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• 2000

8인치 쵸크랄스키 실리콘 단결성 성장에 있어서, 계면에서의 온도기울기, 산소, 농도 및, 반경방향의 산소농도 분포에 미치는 아르곤 가스 유동의 영향을 조사하였다. 아르곤의 유입량을 증가시킴에 따라 계면 근처 결정내 온도기울기가 증가하였으며. 결정내 산소농도는 감소하였다. 한편, 반경방향의 산소농도 균일성은 악화됨이 관찰되었다. 실험 결과를 종합하여 볼 때, 아르곤 유동이 산소 농도 및 균일 분포성 등의 결정 특성에 중요한 영향을 미치는 성장 공정변수임을 확인할 수 있었다.

• 품질경영학회지
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• 제9권2호
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• pp.15-25
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• 1981

This paper deals with the experimental study on the behavior of fuel flow in intake manifold of gasoline engine. The main purpose of this study is an analysis of air stream velocity, behavior of liquid film flow, generation of atomization and atomization rate by using the basic apparatus which is manufactured the visible, straight tube type model of intake manifold. As the result, we have found factors which influenced on the behavior of liquid film flow in intake manifold.

• 산업기술연구
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• 제29권B호
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• pp.199-205
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• 2009

This study selected Naerin Stream, Inbuk Stream and Buk Stream, branch rivers of Soyang Dam, also area of highland agriculture as test sites and measured flow and water quality, particularly eutrophication factors (BOD, COD, T-N, and T-P) in precipitation season and non precipitation season for a year, 2008. Based on the result, the study examined the change in water quality in relation to flow, and created flow discharged - pollution loads regression line by estimating pollution loads flowed from each branch river. And the study calculated annual pollution discharge loads for unit area and proposed regression equation on it by using regression analysis.

• 소성∙가공
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• 제12권8호
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• pp.738-743
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• 2003

The major problems of a plastic injection mould can be devided into two kinds, one is in mould another in injected parts. Most of defects of the former comes from mould design, such as, structure and working. The latter are weld line, warpage, sink mark, burning, flow mark, scratching, shading, black hole and so on. Most of problems in injection molding are difficult to find the reason because of complexity. The purpose of this paper is to improve the quality of plastic injection mould and parts with inquiring the counter plan and analizing troubles of the part of Flat TV Front Cover by flow control method and gas-assisted injection moulding. For minimizing defects of the injection moulded parts, computer aided simulation method for injection mould filling was used. Based on these numerical results, the guidelines of mould design and injection processing condition were established. As a result, the improvement of quality, such as minimizing surface defects of injection moulding parts and troubles in mould was achieved.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.938-943
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• 2003

The characteristics of lightweight cellular concrete has much influence on the compressive strength and flow from the design of mixture. This study is to investigate the characteristics of the compressive strength and flow for the mixture of lightweight cellular slurry. KS F 4039 was compared to the construction system and quality for lightweight cellular comcrete of floating floor. As the result of this study, the standard of the compression strength for target slurry have to lower and an upper limit of flow was judged to be 230mm

• International Journal of Air-Conditioning and Refrigeration
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• 제12권2호
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• pp.70-78
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• 2004

An experimental study on the pressure drop during flow boiling for pure refrigerants Rl34a and R123, and their mixture was carried out in a uniformly heated horizontal tube. Tests were run at a pressure of 0.6㎫ and in the ranges of heat flux 5-50㎾/$m^2$, vapor quality 0-100 percent and mass velocity of 150-600 kg/$m^2$s. Generally, the two-phase frictional multiplier is used to predict the frictional pressure drop during the two-phase flow boiling. The obtained results have been compared to the existing various correlations for the two-phase multiplier. Also, the frictional pressure drop was compared to a few available correlations; The Lockhart-Martinelli correlation considerally overpredicted the frictional pressure drop data for mixture as well as pure components in the entire mass velocity ranges employed in the present study, while the Chisholm correlation underpredicted the present data. The Friedel correlation was found to satisfactorily correlate the frictional pressure drop data except for a low quality region.

• 대한교통학회:학술대회논문집
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• 대한교통학회 2002년도 제41회 학술발표회논문집
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• pp.97-139
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• 2002

The aim of the present study is to find a good quality user equilibrium assignments under time varying condition. For this purpose, this study introduces a dynamic network loading method that can maintain correct flow propagation as well as flow conservation, and it develops a novel solution algorithm that does not need evaluation of the objective function by modifying the Schittenhelm (1990)'s algorithm. This novel algorithm turns out to be efficient and convenient compared to the conventional Frank-Wolfe (1956) algorithm because the former finds solutions based on routes rather than links so that it can maintain correct flow propagation intrinsically in the time-varying network conditions. The application of dynamic user equilibrium (DUE) assignment model with this novel solution algorithm to test networks including medium-sized one shows that the present DUE assignment model gives rise to high quality discrete time solutions when we adopt the deterministic queuing model for a link performance function, and we associate flows and costs in a proper way.

• 환경영향평가
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• 제22권4호
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• pp.319-327
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• 2013

This study was conducted to identify runoff characteristics of pollutants using flow duration curve(FDC) and load duration curve(LDC) in Youngbon A watershed during 2009~2011. A flow rate and pollutant load in the study watershed were estimated by equation of stage-discharge and discharge-loads rating curve. From these methods, BOD, T-N, and T-P have evaluated whether water quality standards would have attained. Results showed that BOD loads of about 50% plotted above the LDC, while T-N and T-P loads of about 50% plotted below the curve. It means that BOD of about 50% have exceeded the water quality criteria, while T-N and T-P of about 50% have complied with the water quality standards. Meanwhile, BOD, TN and T-P loads plotted above the LDC of low flows, implying that they were more affected by point pollution sources than nonpoint pollution sources in the study watershed.

• Journal of Oral Medicine and Pain
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• 제46권4호
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• pp.131-135
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• 2021

Purpose: Depression is a condition that weakens psychosocial functioning and reduces quality of life. In Korea, the prevalence of depression among the elderly is 29.2% and depression is a considerable public health concern for the elderly. Depression has a statistically significant relationship with oral conditions such as number of teeth and salivary flow rate. Oral health-related quality of life (OHRQoL) is the concept including subjective evaluations of psychological, physical and social aspects of oral health. Tooth loss and hyposalivation can affect mental health and quality of life. Our study was designed to identify the relationship among the number of teeth, salivation, OHRQoL, and depressive symptoms in the elderly in Korea. Methods: We recruited 100 participants, aged over 65 years, and assessed their number of teeth, unstimulated salivary flow rate. All participants filled out oral health impact profile 14 (OHIP-14) and Zung self-rating depression score (SDS) for checking OHRQoL and depressive symptoms. Statistical analysis was done by R program. Results: We found that the positive relationship between OHIP-14 and SDS after Mann-Whitney test (p=0.03). The lower SDS group had an OHIP-14 median score of 4. On the other hand, the higher SDS group had a median value of 7.5. The other factors (number of teeth and salivary flow rate) did not show correlations with OHIP-14 or SDS. Conclusions: OHRQoL and depressive symptoms have significant correlation.

• 한국수자원학회논문집
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• 제35권5호
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• pp.525-539
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• 2002

용담댐의 건설에 따른 방류조건의 변화가 대청호의 유입수질에 미치는 영향을 파악하기 위하여 WASP5 모델을 이용하여 BOD, 총인 그리고 총질소 농도를 예측하였다. 수질 예측 시나리오는 크게 다음과 같이 세 가지로 구분하였다; 첫째, 금강의 유량이 대청댐의 운영이 시작된 이래 최대 갈수년(1994)과 최대 풍수년(1987)과 같다고 보는 두 가지 조건, 둘째 용담댐에서 방류되는 유량을 연구기간 중(1998년) 실측된 유량과 같다고 보는 경우와 용담댐 방류 계획안에 따라 각각 5.4, 8.9, 12.4, 16.4 ㎥/s로 방류되는 경우 등 다섯 가지 유량조건, 셋째, 용담호에서 방류되는 수질이 1998년에 실측된 수준을 유지하는 경우와 우리 나라 수질기준으로 1급수와 2급수에 해당되는 경우 등 세 가지 수질 조건. 수질 예측 결과 용담댐으로부터의 방류량의 변화는 금강의 수질과 밀접한 관계를 나타내었으며 금강의 수량이 적은 경우 용담호의 영향은 더욱 뚜렷하게 나타났다. 특히 총질소와 총인 농도의 경우는 각 조건에 대하여 용담댐으로부터의 방류량이 증가됨에 따라 점차로 수질이 개선되는 경향을 나타내었다. 그러나 BOD 농도의 경우는 실측 수질(98년 환경부 측정자료)이 1급수(1 mg/ι) 보다 양호한 수질을 나타내므로 1급수(1 mg/ι)와 2급수(3 mg/ι)의 수질로 방류되는 것을 가정하는 경우에는 방류량의 증가에 따라 용담호 하류의 수질은 오히려 악화되는 결과를 나타내는 것으로 예측되었다. 용담호 부근의 현재 수질은 총질소의 경우는 5급수의 기준(1.5 mg/ι)을 상회하며, 총인의 농도는 3급수 (0.03∼0.06 mg/ι) 정도의 수질을 나타낸다. 유역에서 영양염류의 오염부하를 관리하는 것이 기술적, 경제적으로 한계가 있는 것을 감안할 때, 용담호 방류수내의 영양염류 농도는 크게 개선되지 못할 것으로 예상된다. 따라서 용담호의 방류량 변화가 대청호의 수질에 미치는 영향은 용담호와 용담호 하류부의 수질 및 유량조건에 따라 각각 다르며, 합리적인 수자원의 관리를 위해서는 현실적인 자료 및 여건을 충분히 고려하여 분석하고 판단하는 것이 바람직하다.