• 한국자동차공학회논문집
• /
• 제6권4호
• /
• pp.86-100
• /
• 1998

The impingement of the fuel spray on the wall within the combustion chamber in compact high-pressure injection engines and on the intake port wall in port-fuel-inje- ction type engines is unavoidable. It is important to understand the characteristics of impinging spray because it influences on the rate of fuel evaporation and droplet distrib- ution etc. In this study, the numerical study for the characteristics of spray/wall interaction is performed to test the applicability and reliability of spray/wall impingement models. The impingement models used are stick model, reflect model, jet model and Watkins and Park's model. The head of wall-jet eminating radilly outward from the spray impingement site contains a vortex. Small droplets are deflected away from the wall by the stagnation flow field and the gas wall-jet flow. While the larger droplets with correspondingly higher momentum are impinged on the wall surface and them are moved along the wall and are rolled up by wall-jet vortex. Using the Watkins and Park's model the predicted results show the most reasonable trend. The rate of increase of spread and the height of the developing wall-spray is predicted to decrease with increased ambient pressure(gas density).

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 춘계학술대회논문집
• /
• pp.969-973
• /
• 2007

The heavy-weight floor impact sound field of the receiving room in a testing building with bearing wall structure was investigated using bang machine and impact ball. The sound field was investigated through the impact sound pressure level distribution by the field measurement and computational analysis. Predicted sound field using the computational analysis agree with measurement result in the low frequency band. Result shows that standard deviations of the single number rating value are about 2dB in each impact source. Particularly, impact sound pressure level at 120cm height in 63Hz octave band was 5dB lower than spatial averaging value. It was found that receiving positions in the ministry of construction and transportation notice should be reconsidered.

• 대한전자공학회논문지SD
• /
• 제41권1호
• /
• pp.1-8
• /
• 2004

Quantized memory addressing (QMA) 이론을 바탕으로 새로운 PDP 계조 구현을 수행하는 방법을 개발하였다. 어드레스 펄스 폭을 조절함에 따라 셀에 기입되는 벽전하 양은 "fully on", "off" 그리고 "half on"의 세 단계를 가지게 된다. 이 세 단계의 벽전하를 이용하여 7개의 서브필드로 255단계의 계조를 표현할 수 있다. 더욱이 기존의 구동 방법과는 달리 인접한 두 계조를 표현하기 위해 사용하는 서브필드들이 동영상 의사윤곽을 제거한다. 이 방법은 7개의 서브필드를 사용함으로써 12개의 서브필드를 이용하여 동영상 의사 윤곽을 저감시킨 방법에 비해 유지 방전 시간을 $70\%$이상 증가시킨다.

• 한국실내디자인학회논문집
• /
• 제22권3호
• /
• pp.33-42
• /
• 2013

The purpose of this study was to analyze the design trend of the vertical garden design in the indoor space through the examples of green wall in the lobby space. For the analysis, this study looks into the 'Guide for the Building Greening System' to understand the technical consideration for the green wall. After that, the key design elements was drawn from existing green walls through the literature review and field survey and field-survey. The study picked six green walls which was completed after 2000 in the lobby space in Seoul. The major findings of this study were as follows: First, the design factors mainly depend on the plant selection, which leads to the outlook and texture of the vertical walls. The texture is expressed by the two-dimensional or three-dimensional planting methods which is related to the selection of plant species. Second, the vertical walls in the lobby area should be planned for the function of space which could be transition, human traffic, mood and attraction. Third, the vertical wall should be integrated with the surroundings in order to reinforces the dynamic or static space experience.

• 한국주거학회논문집
• /
• 제27권5호
• /
• pp.25-35
• /
• 2016

he objective of this study was to investigate home network systems presently applied in multi-housing complexes and resident's usage to improve the utilization of these systems and services as well as maintenance methods. Subjects were 27 housing complexes equipped with home network systems in west Pangyo area. The investigation methods of communal network systems were observed and photographed. Unit systems were investigated through photography, interviews, and observation focusing on the utilization of Wall-Pads by visiting one unit of each housing complex. The results are as follows: (1) Most housing complexes that we investigated were built with high-grade IT infrastructure. Also, remote meter reading, electronic security, vehicle access, and building access systems were established. Wall-Pads with similar functions were installed in 23 housing complexes, excluding private rental housing complexes. (2) Even though people were well aware of the need for common systems within their housing complexes, only 10~20% of Wall-Pad menus were used. (3) Low utilization rates of home network stem from Wall-Pad menus which were user-unfriendly, and a lack of user training for the complex's common system and unit system. Therefore, to promote active use of home network systems, the systems must be diversified in accordance with user characteristics. In addition, the Wall-Pad menus should be reorganized to be user-friendly.

• Korea-Australia Rheology Journal
• /
• 제19권3호
• /
• pp.147-156
• /
• 2007

The orientation and deformation of polymer chains in a confined channel flow has been investigated. The polymer chain was modeled as a Finitely Extensible Nonlinear Elastic (FENE) dumbbell. The Brownian configuration field method was extended to take the interaction between the flow and local chain dynamics into account. Drag and Brownian forces were treated as anisotropic in order to reflect the influence of the wall in the confined flow. Both Poiseuille flow and 4 : 1 contraction flow were considered. Of particular interest was molecular tumbling of polymer chains near the wall. It was strongly influenced by anisotropic drag and high shear close to the wall. We discussed the mechanism of this particular behavior in terms of the governing forces. The dumbbell configuration was determined not only by the wall interaction but also by the flow type of the geometric origin. The effect of extensional flow on dumbbell configuration was also discussed by comparing with the Poiseuille flow.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제6권4호
• /
• pp.894-903
• /
• 2014

Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA) method is presented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosure panel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently large so that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison of the predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It is found that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss is dominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside the enclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic power from the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
• /
• pp.5-6
• /
• 2010

본 연구에서는 균열 이후의 콘크리트 벽체에 대해 대각 일축 압축장과 세 삼각형으로 구성된 두 개의 균질한 삼각형 응력장을 고려하고, 이에 대해 직각방향으로 발생되는 강판의 인장응력의 조합을 가정하여 세장한 합성 전단벽의 전단강도를 추정하는 것을 목적으로 한다.

• 한국지반공학회논문집
• /
• 제22권5호
• /
• pp.39-45
• /
• 2006

본 연구에서는 폐콘크리트를 이용한 지오백 옹벽의 거동특성 평가를 위해 대형 압축강도시험과 현장계측을 수행하였다. 연구의 주요내용으로는 폐콘크리트 지오백의 강도, 횡방향 토압, 뒷채움재의 변형특성, 벽체의 수평변위 거동 평가 등이다. 연구결과를 통해 폐콘크리트를 이용한 지오백 옹벽의 변형이 보강토 옹벽의 허용변형 이내의 안정적인 거동을 보이는 것을 알 수 있다. 또한 폐콘크리트 이용 지오백 옹벽은 재활용 순환골재 사용에 따른 경제성 및 조립시공에 따른 시공성 향상 등의 효과가 있을 것으로 판단되었다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.2297-2302
• /
• 2007

Numerical simulations are conducted to analyze conjugate heat transfer characteristics in a ribbed channel. In this simulation, the effects of Reynolds number and heat capacity of the solid channel wall on convective heat transfer are observed in the turbulent flow regime. In the case of the conducting wall against isothermal wall, the relative ratio of the thermal resistance between the solid wall and the flow field varies with Reynolds number. Thus the characteristics of the conjugate heat transfer are changed with the Reynolds number. Heat capacity ratio affects the temperature fluctuation inside solid wall. The temperature fluctuation inside the solid wall decreases with increasing the heat capacity of the solid wall so that the convective heat transfer increases. When the thermal conductivity ratio is smaller than 10, the effects of flow characteristics on heat transfer are changed.