• 보존과학회지
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• 제38권4호
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• pp.254-264
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• 2022

Built in the 6th and 7th centuries during the Baekje period, the Buyeo Royal Tombs consist of seven tombs, including Tomb No. 1, which contains murals. To preserve Tomb No. 1 from damage caused by microorganisms, periodic microbial-distribution investigations are conducted. Following such investigations in August 2016, June 2018, and November 2019, the microbes were classified according to the investigation period, location of collection, and space. This study compares and analyzes the results. The concentration of airborne microorganisms in Tomb No. 1 and the number of microbial genera identified in each space of the tomb decreased as proximity to the main room with murals diminished. During the investigation period, the genera Bacillus, Cladosporium, Penicillium, and Streptomyces were commonly identified on Tomb No. 1. The microorganisms collected from the main room walls were mostly isolated from the east and west walls where the genera Bacillus, Cupriavidus, Paenibacillus, Pseudomonas, and Streptomyces were commonly identified in three or more walls. In particular, the genus Streptomyces is a dangerous strain capable of damaging murals by penetrating into and discoloring the pigments on them. The data generated from this study may be useful for future research on microbial distribution in other domestic mural tombs and those located in North Korea and abroad.

• 대한기계학회논문집B
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• 제36권8호
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• pp.821-828
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• 2012

CPU의 발열량 증가는 서버를 통과하는 배출공기와 유입공기와의 상당한 온도차를 발생시키고 이로 인해 배출공기의 재순환 현상과 유입공기의 바이패스 현상이 발생한다. 이는 데이터센터 냉각시스템의 효율저하를 발생시킨다. 따라서 CRAC의 제어를 통해 유입공기와 배출공기를 분리하는 것이 데이터센터 냉각시스템의 중요한 목표이다. 본 연구에서는 CFD 해석 코드인 ICEPAK을 이용하여 데이터센터에 대한 수치해석을 진행하였다. 실내부로 유입되는 공기유량의 변화에 따른 CPU의 온도와 실 전체의 온도분포를 분석하였다. 이를 통해 CPU의 발열량에 따른 최적 유입유량을 선정하였다. CPU 발열량이 100, 120, 140 W인 경우 유입유량이 $0.15m^3/s$인 지점에서 발열제거와 온도분배가 가장 잘 이루어졌다. RTI 성능지표를 이용하여 해석결과를 검증하였고 RTI 값이 81인 경우 가장 안정적인 결과를 보였다.

• Journal of Magnetics
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• 제13권3호
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• pp.110-113
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• 2008

In this study, heavy rare earth garnet $Tb_2Bi_1Ga_1Fe_4O_{12}$ powders were fabricated by a sol-gel and vacuum annealing process. The crystal structure was found to be single-phase garnet with a space group of Ia3d. The lattice constant $a_0$ was determined to be 12.465 ${\AA}$. From the analysis of the vibrating sample magnetometer (VSM) hysteresis loop at room temperature, the saturation magnetization and coercivity of the sample are 7.64 emu/g and 229 Oe, respectively. The N$\acute{e}$el temperature($T_N$) was determined to be 525 K. The M$\ddot{o}$ssbauer spectrum of $Tb_2Bi_1Ga_1Fe_4O_{12}$ at room temperature consists of 2 sets of 6 Lorentzians, which is the pattern of single-phase garnet. From the results of the M$\ddot{o}$ssbauer spectrum at room temperature, the absorption area ratios of Fe ions on 24d and 16a sites are 74.7% and 25.3%(approximately 3:1), respectively. These results show that all of the non-magnetic Ga atoms occupy the 16a site by a vacuum annealing process. Absorption area ratios of Fe ions are dependent not only on a sintering condition but also on the temperature of the sample. It can then be interpreted that the Ga ion distribution is dependent on the temperature of the sample. The M$\ddot{o}$ssbauer measurement was carried out in order to investigate the atomic migration in $Tb_2Bi_1Ga_1Fe_4O_{12}$.

• 한국수산과학회지
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• 제56권6호
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• pp.818-825
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• 2023

The surge in online seafood consumption has increased parcel delivery, leading to a need to implement effective preservation methods. As the cold chain system is not fully established in Korea, styrofoam boxes and cold packs are commonly used for low-temperature seafood distribution. The impact of cold packs on product preservation depends on the number utilized. Herein, the freshness of vacuum-packed frozen fish fillets (Paralichthys olivaceus and Scomber japonicus) stored at 25±0.5℃ for up to 84 h was measured. Chemical (pH and volatile base nitrogen), microbiological (viable cell count), and physical (odor intensity) properties were assessed using 2 or 4 cold packs in a styrofoam box. Four cold packs yielded lower values, indicating superior freshness, and extended fish freshness by approximately 12 h compared with two cold packs. Therefore, it is recommended to use a minimum of 4 cold packs (-350 g/cold pack) in a styrofoam box for distributing approximately 300 g of frozen fish fillets at room temperature during the summer, considering an average delivery period of 2 days in Korea.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.457-462
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• 2012

Daylighting software is an important component to predict the performance of daylighting system in advance of a field demonstration study with installing them in buildings. PHOTOPIA is a powerful software to generate a candela distribution curve(CDC) of an active daylighting system like a tracking dish concentrator. With PHOTOPIA, a set of candela distribution curves was generated under clear sky conditions and different solar altitude angles. The candela distribution curves were then imported to RADIANCE for rendering and analysis on the daylighting performance of a tracking dish concentrator when it installed in a actual class room without windows. As a result, the daylight collection efficiency of the dish concentrator was 68.4% when we assumed that there was no tracking error. It was found that candela(cd) and total lumens(lm) increased with solar altitude rising, whereas the distribution angle was fixed. The illuminance uniformity on the work plane in the class room was relatively low, 0.12, while the illuminance uniformity on the area of $2.7m^2$ to which the light was illuminated was considerably high, 0.60. The maximum illuminance was 1,340lux with a solar altitude angle of 80 degrees.

• 태양에너지
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• 제17권2호
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• pp.13-22
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• 1997

본 연구에서는 실내로 유입되는 온기와 실내공기사이의 온도차 및 유입속도에 따라 발생되는 부력의 영향 및 실내로 유입된 온기의 혼합특성에 관한 열유동특성을 파악하였다. 혼합도의 정의로부터 임계속도($1.2{\sim}1.6m/s$)전 후로 기하학적영향에 대하여서 혼합과의 관계를 파악할 수 있었다. 그리고 축열표율과의 관계는 속도가 크고 기준온도차가 작을수록 부력의 영향을 적게 받아서 아네모스형, 베인형 모두 높은 축열효율을 나타냈다. 그리고 속도가 클 때는 베인형이 전반적으로 우수한 축열효율을 나타냈다. 따라서 유입속도에 의한 영향이 기준온도차에 의한 영향보다 지배적임을 알 수 있었다.

• Archives of Plastic Surgery
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• 제42권1호
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• pp.34-39
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• 2015

Background Facial laceration is the most common injury encountered in the emergency room in the plastic surgery field, and optimal treatment is important. However, few authors have investigated this injury in all age groups or performed follow-up visit after repair. In the present study, the medical records of patients with lacerations in the facial area and underwent primary repair in an emergency room over a 2-year period were reviewed and analyzed. Methods Medical records of 3,234 patients with lacerations in facial area and underwent primary repair in an emergency room between March 2011 and February 2013 were reviewed and identified. Results All the 3,234 patients were evaluated, whose ratio of men to women was 2.65 to 1. The forehead was the most common region affected and a slip down was the most common mechanism of injury. In terms of monthly distribution, May had the highest percentage. 1,566 patients received follow-up managements, and 58 patients experienced complications. The average days of follow-up were 9.8. Conclusions Proportion of male adolescents was significantly higher than in the other groups. Facial lacerations exhibit a 'T-shaped' facial distribution centered about the forehead. Careful management is necessary if a laceration involves or is located in the oral cavity. We were unable to long term follow-up most patients. Thus, it is necessary to encourage patients and give them proper education for follow-up in enough period.

• 대한방사선기술학회지:방사선기술과학
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• 제44권3호
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• pp.205-210
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• 2021

The purpose of this study was to analyze the spatial dose according to the distance by location of medical workers when using a mobile X-ray fluoroscopy device in the operating room through a simulation experiment. The MCNPX program was used for the simulation, and the location of medical workers was set around the operating table, and the spatial dose distribution according to the distance and changes in imaging conditions was evaluated. As a result, The highest score was 2.74×10^-4 mGy, 2.72×10^-4 mGy, and 1.18×10^-4 mGy based on the 10 cm distance from the operating table. Spatial dose depending on the distance 100cm, A point 5.15×10^-5 mGy is decreased 19% of 10cm, D point 5.12×10^-5 mGy, 19 % of 10cm, and G pint, 1.73×10^-5 mGy is reduced by 15% of 10cm. Based on this study, medical-related workers directly or indirectly participating in surgery carry potential risks of radiation exposure during surgery, but there are difficulties in radiation protection due to the nature of their work. Therefore, efforts to reduce exposure suitable for the operating room environment will be required.

• 한국환경과학회지
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• 제8권4호
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• pp.423-429
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• 1999

This study was performed to investigate the fluid flow characteristics, the temperature distribution, humidity and PMV(Predicted Mean Vote of thermal sensation) distributions of the 3-dimensional room with side wall exhaust. The finite volume method and turbulence k-$\varepsilon$ models with the SIMPLE computational algorithm are used. As the results of the three dimensional simulations, the region of exceeding Y=1.5m was high temperature and humidity. The inlet velocity and temperature were influenced to the floor strongly, and the room PMV was about -1.0 except the inlets.

• 한국전산유체공학회지
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• 제9권4호
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• pp.13-19
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• 2004

Flow distribution of a mid-size vehicle in engine room was investigated numerically to analyze the flow performance of given design cases in a front body of the mid-size vehicle. The data analyzed are the mass flow rate at the upper and lower openings, in the radiator, and the degree of non-uniformity of the velocity field at the inlet of the radiator. It is presented that the shape of the front end and the presence of the undercover greatly affect the flow fields, therefore, the flow performance.