• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.269-270
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• 2018

Urea is liquefied when it is dissolved in water and has the effect of increasing water. It is known that when using urea, it is generally possible to reduce the number of design units in order to ensure the same flow-ability, because the effect of increasing the water when using urea in the manufacturing of concrete is known. In this study, the change of basic properties of concrete when using urea was investigated in concrete production, and the effect of reducing the unit yield was confirmed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.73-76
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• 2005

This study aims to suggest a simple and convenient design for a mix proportion method for high performance concrete by determining the optimum fine aggregate ratio and minimum binder content based on the maximum density theory. The mix design method introduced in this study adopted the optimum fine aggregate ratio with a minimum void and binder content higher than the minimum binder content level. The research results reveal that the method helps to reduce trial and error in the mixing process and is a convenient way of producing high performance concrete with self filler ability. In an experiment based on the mix proportion method, when aggregate with the fine aggregation ratio of 41$\%$ was used, the minimum binder content of high performance concrete was 470kg/$m^{3}$ and maximum aggregate capacity was $0.657m^{3}/m^{3}$. In addition, in mixing high performance concrete, the optimal slump flow to meet filler ability was 65$\pm$5cm, V load flow speed ranged from 0.5 to 1.5.

• 대한금속재료학회지
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• 제48권4호
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• pp.326-334
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• 2010

Porous and net-shaped tantalum powder for a capacitor was formulated in a SHS (self-propagating high-temperature synthesis) process. However, this powder, which has weak strength among its particles and low flow ability, cannot be used for a capacitor. Therefore, this powder was sintered in a high-vacuum furnace to increase agglomeration to improve the flow ability, bonding strength among the particles, and shrinkage during pellet sintering. Finally, it was deoxidated with 2 wt% Mg powder to remove the increased surface oxygen that arose during the sintering process. The final product was analyzed in terms of its chemical and physical properties and was compared with a commercial powder used by a capacitor manufacturer.

• Korea-Australia Rheology Journal
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• 제18권3호
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• pp.161-167
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• 2006

This study presents results on the numerical simulation of Newtonian and non-Newtonian flow in a channel obstructed by an asymmetric array of obstacles for clarifying the descriptive ability of current non-Newtonian constitutive equations. Jones and Walters (1989) have performed the corresponding experiment that clearly demonstrates the characteristic difference among the flow patterns of the various liquids. In order to appropriately account for flow properties, the Navier-Stokes, the Carreau viscous and the Leonov equations are employed for Newtonian, shear thinning and extension hardening liquids, respectively. Making use of the tensor-logarithmic formulation of the Leonov model in the computational scheme, we have obtained stable solutions up to relatively high Deborah numbers. The peculiar characteristics of the non-Newtonian liquids such as shear thinning and extension hardening seem to be properly illustrated by the flow modeling. In our opinion, the results show the possibility of current constitutive modeling to appropriately describe non-Newtonian flow phenomena at least qualitatively, even though the model parameters specified for the current computation do not precisely represent material characteristics.

• 산업경영시스템학회지
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• 제5권6호
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• pp.41-48
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• 1982

This paper analyzed md developed flow - shop sequencing heuristic method. The essence of the heuristic approach is in the application of selective routine that reduce the size of a problem. The advantages of this approach are consistency. Speed, endurance and the ability to cope with more data and larger systems than is humanly possible, In recent years many heuristic procedures have been suggested for the flow - shop sequencing problem. Although limited comparisons of these procedures have been made, a full scale test and evaluation have not been reported previously. The maximum flow - time criterion is selected as the evaluation criterion is selected as the evaluation criterion of flow - shop's efficiency. The author evaluated these 3 heuristic method's performance. By the evaluation of the result, we can see that the modified methods produce a shorter maximum flow - time than the original methods.

• 한국환경과학회지
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• 제21권12호
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• pp.1463-1468
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• 2012

The purpose of this work is to study the desorption characteristics of water vapor on zeolites saturated with water vapor. Three kinds of zeolite; zeolite 3A, zeolite 4A, and zeolite 5A were used as adsorbent. The desorption experiments with several different temperatures in the range of $90{\sim}150^{\circ}C$ and several different flow rates in the ranges of 0~0.4 L/min on zeolite bed were carried out. The desorption ability of water vapor was most effective on zeolite 5A among the compared zeolites. The higher the desorption temperature of water vapor was, the faster the desorption velocity was. The desorption ability of water vapor with an air supply was higher than that without an air supply. The most appropriate air flow rate was considered as 0.1 L/min.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.1024-1040
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• 2014

The theoretical background and a numerical solution procedure for a time domain hydroelastic code are presented in this paper. The code combines a VOF-based free surface flow solver with a flexible body motion solver where the body linear elastic deformation is described by a modal superposition of dry mode shapes expressed in a local floating frame of reference. These mode shapes can be obtained from any finite element code. The floating frame undergoes a pseudo rigid-body motion which allows for a large rigid body translation and rotation and fully preserves the coupling with the local structural deformation. The formulation relies on the ability of the flow solver to provide the total fluid action on the body including e.g. the viscous forces, hydrostatic and hydrodynamic forces, slamming forces and the fluid damping. A numerical simulation of a flexible barge is provided and compared to experiments to show that the VOF-based flow solver has this ability and the code has the potential to predict the global hydroelastic responses accurately.

• 대한치과의사협회지
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• 제15권2호
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• pp.145-151
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• 1977

The author performed Snyder test, estimation of salivary flow rate, salivary viscosity test, salivary buffering capacity test, M-R test, oral hygiene ability test, estimation of oral glucose clearance time and plaque reformation test in the 107 male Koreans aged form the age of 20 to 29, in order to detect and control the active cariogenic factors contributing to caries development on the individual basis. Thereafter, the data from 8 kinds of caries activity test were analysed and evaluated. The obtained results were as follows: 1. Snyder test was positive in 86.0% of total tested persons, and among those showing positive Snyder test reaction, slight caries activity was appeared in 39.1%, moderate caries activity in 23.9%, and marked caries activity in 37.0%. 2. Salivary flow rate was under the average flow amount in 53.3%. 3. Salivary buffering capacity was low in 22.4%. 5. Buffering capacity of dental plaque was high in 12.5%. 6. Oral hygiene ability was insufficient in all persons tested. 7. Oral glucose clearance time was long in 42.1%. 8. Plaque reformation rate was high in 8.4% of the 107 persons tested.

• 한국정보처리학회논문지
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• 제6권10호
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• pp.2764-2771
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• 1999

ATM은 높은 처리 능력, 대역 확장, 그리고 다중 서비스 트래픽을 지원할 수 있는 능력 때문에 최근 주목을 받아 왔다 그러나 그 동안 네트워킹 프로토콜이 대부분 비연결형인 것에 반해 ATM은 연결 지향적이다 ATM에서 현재 서비스를 제공하기 위한 대안은 라우탱 기능을 제공하는 스위칭 하드헤어를 적용한 라우터이다 본 논문에서는, 스위치를 이용한 라우터를 설명하고 성능을 시뮬레이션 하였다 시뮬레이션 결과, 라우팅 지연은 플로우 개수에 따라 증가하였다 플로우 채널-유지 시간이 30,000 셀-시간일 때 셀 지연은 가장 적었다. 회선 효율은 플로우 설정 시간이 20 30 셀-시간일 때 급격히 증가하였다. 이 시뮬레이션 결과는 ATM 스위치를 이용한 라우터의 성능을 예측하기 위하여 사용될 수 있다.

• 디지털산업정보학회논문지
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• 제14권4호
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• pp.177-187
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• 2018

The purpose of this study is to investigate the influence of learning flow, learning interest, and academic achievement by dividing the time when class was taught by Havruta. The Havruta teaching method is a traditional Jewish method of learning, with a one-on-one discussion with a partner that has a positive impact on each other. Havruta teaches learners through various perspectives and perspectives, helping them to improve their learning ability by attracting new ideas and solutions. In the computer lab, there is a big difference between the students according to the learner's abilities. Therefore, it is thought that the Havruta teaching method will help the learners who have lost interest in learning and improve the learning ability in the conventional way which does not consider personal abilities. do. In this paper, based on the friendship teaching model of the Havruta teaching style, the experimental group was taught through the Havruta practice and the play. Through the pre- and post-test, the students who taught the class with the help of the verbal method improved the learning flow, the learning interest and the academic achievement.