• 공업화학
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• 제9권7호
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• pp.950-955
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• 1998

본 연구는 두 종류의 Polyethlene Glycol(PEG, Mw; 8000, 20000)을 cross-flow로 한외여과(막; 분획분자량 6000, 20000)함에 있어서 시간, 운전압력, 유입농도, 그리고 순환유량의 변화에 따라 투과유속과 제거율의 관계를 조사하는데 목적을 두고 있다. 실험진행에 있어서 운전압력은 7, 14, 28 psi의 3단계로, 순환유량은 1000 mL/min와 2000 mL/min 두 가지로, 그리고 유입농도도 100 mg/L과 1000 mg/L의 두가지로 하여 실행하였다. 투과유속은 PEG의 분자량과 농도가 작을수록 압력증가와 함께 증가하였으며, 겉보기제거율($R_o$)은 PEG의 분자량과 농도가 클수록 증가하였다. 그러나 압력이 증가되었을 때 $R_o$는 감소하였다. 일정한 압력하에서 PEG수용액의 투과유속과 $R_o$는 시간변화(8 h)에 관계없이 일정하였다. 순환유량의 변화에 있어서 투과유속에는 거의 영향이 없었으나, $R_o$는 순환유량이 큰 경우가 높게 나타났으며, 두 순환유량의 경우 모두 압력증가와 함께 $R_o$는 감소하였다. 한편, 투과유속과 조작압력의 거동을 분석하기 위해 사용된 투과도비($\alpha$)는 조작압력과 순환유량의 증가와 함께 증가하였으며, 모든 경우에서 1보다 작게 나타났기 때문에 농도분극현상을 분석할 수 있었다. 그리고 물질전달계수로부터 얻은 진제거율(R)은 압력증가와 함께 감소하였으며, 선유속과 PEG의 분자량이 클수록 높게 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.513-518
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• 2003

The piston slap phenomenon is one of the major noise source of reciprocating compressors used in household electric appliances. In response to public demand, strict regulations are increasingly being imposed on the allowable noise level which is caused mostly by household electric appliances. In this paper, the dynamic behavior of suction and discharge valves are analytically calculated and the lubricant behavior between piston and cylinder are investigated using two-dimensional Reynolds equation. And the piston slap caused by the piston secondary motion is investigated by the finite element method.

• 한국실내디자인학회논문집
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• 제13권6호
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• pp.29-38
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• 2004

The purpose of this study is to provide design guidelines on office layouts to improve workers' concentration and communication behavior while supporting work processes. Among the present office types, benzene-type was preferred the most was providing better concentration. Regarding communication, link and benzene were preferred types. In present office types, workers were satisfied in communication more than concentration. To increase concentration level, acoustical privacy was indicated as the most important factor In conclusion, to support both concentration and communication in office, the team area should be divided into smaller sub-team areas. The sub-team areas may support interaction within a group while preventing unnecessary distraction. The major circulation of work process should be formed outside of the sub-team areas to provide concentration within the groups.

• 대한토목학회논문집
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• 제11권2호
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• pp.27-37
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• 1991

음부력을 갖는 유체가 소규모 저수지로 유입되어 일어나는 밀도류의 거동 및 순환이 차원해석과 수리실험을 이용하여 해석된다. 무차원침강점 및 밀도류전면속도, 밀도류전면이동거리, 머리 뒤의 밀도층내회석 등은 유입밀도후르드수, Fre의 영향을 받으며 밀도층의 두께, 흐름양상 및 저수지내 밀도의 변화는 밀도류전면이 하류단에 도달하여 반사되기 전과 후의 양상이 현저하게 다르다. 밀도층의 두께는 전자의 경우에는 Fre, 후자의 경우는 시간과 Fre의 영향을 받으며 이들은 지수식으로 표현할 수 있다.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3551-3566
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• 2022

The STELLA program was launched to support the PGSFR development in 2012 and for the 2nd stage, the STELLA-2 facility was designed to investigate the integral effect of safety systems including the comprehensive interaction among PHTS, IHTS and DHRS. In STELLA-2, the long-term transient behavior after accidents can be observed and the overall safety aspect can also be evaluated. In this paper, the basic design concept from engineering basis to specific design is described. The design was aimed to meet similarity criteria and requirements based on various non-dimensional numbers and the result satisfied the key features to explain the reasoning of safety evaluation. The result of this study was used to construct the facility and the experiment is on-going. In general, the final design meets the similarity criteria of the multidimensional physics inside the reactor pool. And also, for the conservation of natural circulation phenomena, the design meets the similarity requirements of geometry and thermo-dynamic behavior.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1109-1118
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• 2021

The construction of STELLA-2 facility is on-going to demonstrate the safety system of PGSFR and to provide comprehensive understanding of transient behavior under DBEs. Considering that most events are single-phase natural circulation flow with slow transient, STELLA-2 was designed with reduced-height of 1/5 length scale. The ratio of volume to surface area in the vessel can relatively increase resulting in excessive heat transfer. Therefore, a steady-state thermal-hydraulic analysis was performed and the effect of design change to reduce the heat transfer through redan was investigated. The heat transfer through single wall redan in STELLA-2 was 3% of the core power, comparable to 1% of the core power in PGSFR. By applying the insulated redan, about 70% of decrease effect was observed. The effect on transient behavior was also evaluated. The conclusion of this study was directly applied to the STELLA-2 design and the modified version is under construction.

• 한국콘텐츠학회논문지
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• 제16권9호
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• pp.198-210
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• 2016

본 연구는 다크투어리즘 관광지 중 하나인 서대문형무소 역사관을 대상으로 실제 관광자들의 관람동선과 관람행태를 분석하고자 하였다. 이를 위해 선행연구를 통해 도출된 관람동선 유형과 관람자의 행동기록 코드인 'Muse-Ethogram'을 기반으로 직접관찰법을 이용한 행태추적 조사를 실시하였다. 서대문형무소 역사관 관광자들의 관람동선과 관람행태를 분석한 결과, 제안동선(SA), 임의동선(UNA), 유도동선(DA)이 모두 나타났다. 관람자의 관람행태는 이동(M), 정지/관람(SL), 읽음(RE)이 전체적으로 가장 높은 빈도를 보였으며, 다크투어리즘만의 관람행태인 '감정을 표현함(EXP)'이라는 새로운 행태를 발견하였다. 관람자들의 행태패턴은 정지/관람-읽음-이동(SL-RE-M)의 빈도가 가장 높게 나타났다. 이상의 연구결과는 다크투어리즘 관광지의 콘텐츠 구성시 관람동선이나 관람행태, 전시방향관련 계획 및 설계 가이드라인으로 활용될 수 있을 것이다.

• 대한토목학회논문집
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• 제9권4호
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• pp.135-143
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• 1989

깊이 32m인 심층포기장치에서 기포(氣泡)의 형태(形態)와 거동(擧動)에 관하여 실험연구(實驗硏究)를 실시하였다. 연구(硏究) 결과(結果)에 의하면, 심층포기장치의 하향관(下向管)에 설치된 0.06cm의 단일(單一) 오리피스경(經)에서 발생되는 기포(氣泡)의 구체적(球體積) 상당경(相當經)(Dv)은 0.422-0.722cm이고 기포(氣泡)의 형상(形狀)은 타원체(橢圓體)이었다. 기포(氣泡) 체류량(滯留量) 기(氣)-액(液) 접촉면적(接觸面積)은 심층포기장치의 수심(水深) 증가(增加)할수록 감소(減少)하였으며, 기포(氣泡)의 하강속도(下降速度)는 액체(液體)의 순환(循環)유속보다 작고, 기포(氣泡)의 상승속도(上昇速度)는 액체(液體)의 순환(循環)유속보다 약간 크게 나타났다. 심층포기장치내의 기포분포(氣泡分布)는 거의 대수정정규분포(代數定定規分布)를 나타내고 있으며, 또한 기포(氣泡)의 갯수는 수심(水深)이 증가(增加)할수록 감소(減少)하며, 하향관(下向管)이 상향관(上向管)에 비하여 많았다.

• 한국멀티미디어학회논문지
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• 제18권5호
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• pp.663-670
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• 2015

In this study, I have researched the theories about Gibson's real affordance and Norman's perceived affordance which are central fact of affordance, And I have examined the context of affordance in smart-phone interface which was consist of affordance and signifier with viewpoint of amalgamation of Gibson & Norman. The results of this study are as follows; The first, Gibson's real affordance is a physical space in ubiquitous environment that interact through the behavioral space is composed with physical space and electronic space. Norman's perceived affordance is mediated to electronic space and signifier makes a behaviroal space which provide the clue of interaction. The second, signifier can be categorized into visceral, behavioral and reflective signifier based on three brain actions which are visceral, behavior, and reflection. Through the categorization, we can grasp that behavioral and reflective signifies generate visceral signifier. The third, the context of affordance in smart-phone has the structure of circulation. The structure of circulation is as follows: Real affordance makes the perceived affordance, the perceive affordance makes the signifiers and the signifiers make new real affordance. This study could provide the theoretical basis for using signifier in smart-phone interface design.

• 한국조경학회지
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• 제33권1호
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• pp.10-18
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• 2005

The main concept of social carrying capacity is based on the principle that 'there are limits to the number of users a given recreation site can accommodate in order to provide quality of recreation experience'. The quality of the experience is revealed as user's satisfaction and perceived crowding. In this respect, studies of social carrying capacity have been frequently conducted by measuring perceived crowding and satisfaction. The purpose of this study is to identify the variables affecting perceived crowding, and causality bet-ween satisfaction and perceived crowding. Four hundred seventy six visitors were selected at Naejangsan National park on peak day of autumn excursion through on-site survey. The collected data were applied by factor analysis for categorizing the research variables, and multiple regression for finding the causality among variables. The study results are follows. The expectation of crowding, as a normative variable for perceived crowding, are categorized by three factors; circulation, user facility, and landscape. The circulation factor is the most powerful affecting perceived crowding among three factor. The landscape factor, however, do not have statistical significance on perceived crowding. The causality between satisfaction and perceived crowding is found. Although this relation is significant in statistics, magnitude of the coefficient is very small. It might be interpreted that satisfaction cannot be predicted simply from a user's perception of crowding, but a multi-dimensional concept such as adaptation and coping behavior.