• 대한기계학회논문집B
• /
• 제25권12호
• /
• pp.1821-1830
• /
• 2001

The flow around free end of a finite circular cylinder (FC) embedded in an atmospheric boundary layer has been investigated experimentally. The experiments were carried out in a closed-return type subsonic wind tunnel with varying aspect ratio of the finite cylinder mounted vertically on a flat plate. The wakes behind a 2-D cylinder and a finite cylinder located in a uniform flow were measured for comparison. Reynolds number based on the cylinder diameter was about Re=20,000. A hot-wire anemometer was employed to measure the wake velocity and the mean pressure distributions on the cylinder surface were also measured. The flow past the FC free end shows a complicated three-dimensional wake structure and flow phenomenon is quite different from that of 2-D cylinder. The three-dimensional flow structure was attributed to the downwashing counter rotating vortices separated from the FC free end. As the FC aspect ratio decreases, the vortex shedding frequency decreases and the vortex formation length increases compared to that of 2-D cylinder. Due to the descending counter-rotating twin-vortex, near the FC free end, regular vortex shedding from the cylinder is suppressed and the vortex formation region is hardly distinguished. Around the center of the wake, the mean velocity for the FC located in atmospheric boundary layer has large velocity deficit compared to that of uniform flow.

• 한국컴퓨터정보학회논문지
• /
• 제12권2호
• /
• pp.299-305
• /
• 2007

본 논문에서는 온라인 게임에 관련한 국내외 연구동향과 이론들을 고찰하여 보고, 관련 문제에 대한 분석을 통하여 그 부작용에 대한 정책적 대안의 마련을 발제 하고자 한다. 온라인 게임은 이미 우리 사회의 중요한 문화 아이콘으로 자리 잡았고, 한류 열풍의 중요한 테마 중의 하나로써 우리의 대외 신인도 향상에 크게 이바지함은 물론 경제적 부를 창출해 주고 있다. 또한 온라인 게임과 관련 산업에의 투자는 상대적으로 부존자원이 부족한 우리나라의 훌륭한 블루오션점이 될 것으로 예상되고 있다. 그러나 이러한 순작용과 함께 예상치 못한 많은 반작용들이 발생하고 있는데 이에 관해서는 심심치 않게 언론에 보도되고 있으며, 그 심각성은 점점 증가하리라고 예견되고 있다. 이에 개별체계에 산재 되어 있는 온라인 게임 관련 분쟁의 통일적 해결 체제를 구축하여야 할 것이며, 이를 통한 예방적 효과를 거둠은 물론 합리적인 판단의 근거로 작용하게 해야 될 것이다. 또한 온라인 게임이 향후 국가전략산업으로써 한 단계 발돋움 할 수 있는 기회가 될 수 있는 기반을 조성해줘야 할 것이며, 이를 위한 다양한 부문의 학제간 연구가 시도되어야 할 것이다.

• 대기
• /
• 제24권2호
• /
• pp.245-251
• /
• 2014

Statistical trajectory analysis has been widely used to identify potential source regions for chemically and radiatively important chemical species in the atmosphere. The most widely used method is a statistical source-receptor model developed by Stohl (1996), of which the underlying principle is that elevated concentrations at an observation site are proportionally related to both the average concentrations on a specific grid cell where the observed air mass has been passing over and the residence time staying over that grid cell. Thus, the method can compute a residence-time-weighted mean concentration for each grid cell by superimposing the back trajectory domain on the grid matrix. The concentration on a grid cell could be used as a proxy for potential source strength of corresponding species. This technical note describes the statistical trajectory approach and introduces its application to estimate potential source regions of $CO_2$ enhancements observed at Korean Global Atmosphere Watch Observatory in Anmyeon-do. Back trajectories are calculated using HYSPLIT 4 model based on wind fields provided by NCEP GDAS. The identified $CO_2$ potential source regions responsible for the pollution events observed at Anmyeon-do in 2010 were mainly Beijing area and the Northern China where Haerbin, Shenyang and Changchun mega cities are located. This is consistent with bottom-up emission information. In spite of inherent uncertainties of this method in estimating sharp spatial gradients within the vicinity of the emission hot spots, this study suggests that the statistical trajectory analysis can be a useful tool for identifying anthropogenic potential source regions for major GHGs.

• 사상체질의학회지
• /
• 제13권2호
• /
• pp.124-137
• /
• 2001

The purpose of this research was to investigate the inhibitory function among foods and herb drugs. I have gone over literatures of mainly ${\ll}$Eum-Sun-Jung-Yo(飮膳正要)${\gg}$ on the basis of ${\ll}$Dong-Eui-Bo-Gam (東醫寶鑑)${\gg}$ about the properties and flavors of foods and herb drugs. And then I came to get some conclusion as follows. 1. The foods mentioned above are meats, birds, fishes, spices and vegetables. 2. If the foods mentioned above were eaten for a long time, and then it can cause stirring Wind or Qi or Fire inside the body. 3. What it means in the context of the chapter ${\ulcorner}$Sik-Mul-Sang-Ban : Inhibitory Function Among Foods and Herb Drugs(食物相反)${\lrcorner}$ that 'Do not eat the paired foods or herb drugs at a same time' and 'Do not eat the paired foods or herb drugs together for a long time.' 4. The Cold natured foods were not eaten at a same time. 5. The Hot or Warm natured foods were not eaten at a same time. 6. The contrary natured foods were not eaten at a same time. Because they were eaten at a same time, it raise a Occurrence of Cold and Heat syndromes and a Qi disorder.

• 한국공간구조학회논문집
• /
• 제17권2호
• /
• pp.21-32
• /
• 2017

The objective of this study is to analysis the mechanical characteristics on the geometric nonlinear behavior of radial cable roof systems for long span retractable cable roof structures. The retractable roof is designed as a full control system to overcome extreme outdoor environments such as extreme hot or cold weather, strong wind or sunlight, and the cable roof greatly can reduce roof weight compared to other rigid structural system. A retractable cable roof system is a type of structures in which the part of entire roof can be opened and closed. The radial cable roof is an effective structural system for large span retractable roofs, the outer perimeter of the roof is a fixed membrane roof and the middle part is a roof that can be opened and closed. The double arrangement cables of a radial cable truss roof system with reverse curvature works more effectively as a load bearing cables, the cable system can carry vertical load in up and downward direction. In this paper, to analyze the mechanical characteristics of a radial cable roof system with central posts, the authors will investigate the tensile forces of bearing cables, stabilized cables, ring cables, and the deflection of roof according to the height of the post or hub that affects the sag ratio of cable truss. The tensile forces of the cables and the deflection of the roof are compared for the cases when the retractable roof is closed and opened.

• 천문학회보
• /
• 제37권2호
• /
• pp.99.2-99.2
• /
• 2012

We updated the far-ultraviolet (FUV) spectral images of the entire Vela supernova remnant (SNR) using newly processed FIMS/SPEAR data. In the present study, we compare the newly produced FUV images with the X-ray and $H{\alpha}$ images, and examine how the Vela SNR evolves and interacts with the ambient medium on a global scale. The comparison with X-ray images has revealed a FUV filamentary feature corresponding with the boundary of the northeast-southwest asymmetry of the X-ray shell. The relatively low O IV] ${\lambda}1404$ to O III] ${\lambda}{\lambda}1661$, 1666 ratio estimated on the FUV filament is compatible with the previous proposal that the observed asymmetry of the Vela SNR could be due to the ${\gamma}2$ Velorum stellar wind bubble (SWB). The southwest FUV features surrounding a faint extended X-ray region are characterized as the region where the Vela SNR is interacting slightly stronger with ambient mediums within the dim X-ray southwest section. From a comparison with the $H{\alpha}$ image, we identify a ring-like $H{\alpha}$ feature overlapped with an extended hot X-ray feature of similar size and two local peaks of C IV ${\lambda}{\lambda}1548$, 1551 emission. Their morphologies are consistent with the expected shape when the $H{\alpha}$ ring is in direct contact with the near or far side of the Vela SNR. We suggest that the B3V-type star HD 76161 found at the center of the $H{\alpha}$ ring would be the exciting source of the H II region.

• 한국추진공학회지
• /
• 제17권6호
• /
• pp.75-80
• /
• 2013

본 연구에서는 마하 2의 실험실 규모의 풍동장치에서 플라즈마 제트 토치를 점화기로 사용하여 강제점화에 대한 연소 특성을 연구하였다. 하이퍼 혼합기는 혼합기로 사용되었다. 수직분사의 경우, 하나는 하이퍼 혼합기의 웨지면에 충돌하도록 하였으며, 다른 하나는 차가운 주유동으로 바로 분사되도록 하였다. 하이퍼 혼합기와 충돌하는 경우 충돌된 연료는 분산되며 확산 혼합에 의해 혼합성능이 증대된다. 또한 혼합된 가스는 대부분 플라즈마 제트의 열원으로 유입되어 연소 성능을 증대시킨다. 하지만 주유동으로 직접 분사되는 경우는 초음속의 주유동 내에서 점화되지 못하고 많은 양의 연료가 소비된다. 따라서 강제점화방식의 연소의 경우에는 많은 양의 연료-공기 혼합물을 점화가 가능한 열원으로 공급하는 것이 중요하다.

• 한방안이비인후피부과학회지
• /
• 제14권2호
• /
• pp.207-223
• /
• 2001

The Wonyenaejang is equivalent to the (senile)cataract in western medicine. The word cataract is used to describe the natural lens that has turned cloudy. As the natural lens of the eye becomes cloudy, it does not allow light to pass through it. Cataracts usually start as a slight cloudiness that progressively grows more opaque. As the cataract becomes more mature(increasingly opaque and dense), the retina receives less and less light. The light that does reach the retina becomes increasingly blurred and distorted. This causes gradual impairment of vision. If left untreated, cataracts can cause needless blindness. Although there are many kinds of cataracts, a senile cataract is the most common one. We chose the oriental medicine textbooks and the oriental medicine journals that were dealing with the symptoms, etiology, and internal/external treatments. The results were as follows : 1. The main causes of this disease are weak liver and kidney, burning up of the wind and heat in the liver and gall, weak spleen and stomach. 2. As the internal treatment of the Cataract, Geegukjihwangtang is mostly prescribed. 3. As the external treatment of the Cataract, (l) In the field of medicine for external application is commonly prescribed (2) In the field of drug action, frequently used treatments are as follows. emission of the evil, alleviation of fever, removal of lump of blood, and the medicine for external applications. (3) In the field of four Qi, cold medicine is commonly prescribed. (4) In the field of five tastes, bitter/hot/sweet mdicine are commonly prescribed. (5) In the field of toxicity, non-togic medicine is commonly prescribed. (6) In the field of channel distribution, most of the medicine belong to liver channel.

• 한국인터넷방송통신학회논문지
• /
• 제21권1호
• /
• pp.121-129
• /
• 2021

최근 중국에서 발생하는 황사와 더불어 국내에서는 뉴스 등 미디어를 통해 미세먼지가 큰 화제가 되고 있다. 외부에서 발생하는 미세먼지도 있지만, 외부 미세먼지가 내부로 유입되면서 공기 청정기 제품의 구입율이 높아지고 있다. 공기 청정기는 내부에 필터를 사용하고 있으며, 센서를 통해 필터의 교체 유무를 LED 알람을 통해 사용자에게 알려준다. 하지만, 현재 필터율이 얼마나 감소하였는지 측정하고, 작동하는 송풍기의 압력을 결정해주는 제품은 없는 상태이다. 따라서 본 논문에서는 IoT 기기인 아두이노와 미세먼지 센서, 차압 센서를 활용하여 데이터를 직접 생성하고, 측정된 미세먼지와 압력 값을 계산하여 필터율에 따라 필터가 얼마나 노화되었는지 확인할 수 있는 프로그램을 파이썬 프로그래밍을 이용하여 개발하였다.

• 대한건축학회논문집:계획계
• /
• 제35권8호
• /
• pp.23-34
• /
• 2019

The façade, a fundamental function as a skin that protects human life from external environment such as cold and hot weather, snow, rain, and wind, etc, has served as a media for communication between indoor space of the building and outside space. From the media for communication point of view, the approach to envelope design, in which environmental elements are transmitted internally through the filtering of external environments, has been evolving in various ways from the past to the present. Today, modern architecture technologies including curtain wall systems and user-friendly computer programming and environmental analysis programs demonstrate a differentiated approach to envelope design related to the indoor environment. For this reason, it is worth noting that the envelope design factors and trends that appear variously in the UNStudio's projects before and after the 2000s. The factors reflected in the envelop design in conjunction with the indoor environment obtained through the case study of the UNStudio's office projects were daylight environment, thermal environment, ventilation, noise, privacy and view, and consideration for daylight environment and thermal environment was reflected in many cases through the case study. Looking at the changes in the diagrams in order of year, it can be seen that the envelope design using the environmental analysis tool has been performed since 2006. This is a clue to show the envelop design changes from the conceptual method to the data-based one. The diagrams and analysis results related to the envelop design showed that the thermal environment related to solar radiation was the most, and no diagrams and analysis related to the indoor illumination were found. Since 2010, PV panel installation has been shown in the envelope design, which can be found in the increased efficiency of PV panels due to the technological advances and the decrease in production cost.