• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.179-184
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• 2010

This experimental study investigated the effect of tip clearance and bypass flow on the cooling performance of a straight fin heat sink. Both the horizontal and vertical directions of the bypass flow were studied by using a mass flow controller and test sections. The thermal resistance of a heat sink was obtained to elucidate the response of the cooling performance to tip clearance and bypass flow. The thermal resistance of a straight fin heat sink gradually increases with increasing tip clearance. A flow guide unit was employed to reduce the bypass flow. An optimal distance from the leading edge of the heat sink to the flow guide unit was found for the fixed volume flow rate. The contribution of the flow guide unit to the thermal performance of a heat sink increases with increasing volume flow rate.

• Composites Research
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• v.29 no.5
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• pp.236-242
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• 2016

In this work, tensile and in-plane shear tests for thermoplastic glass fiber/polypropylene composites were performed at a thermo-forming temperature and their properties were characterized and mathematically expressed by using the non-orthogonal constitutive model. As for the thermo-forming test, half-dome experiments were carried out by varying the usage of a releasing agent and the weight of holders. As results, the optimum final shape having well-aligned symmetry and no wrinkle formation was obtained when the releasing agent was used, and it was found that the careful control of a holding force is crucial to manufacture the healthy product. Furthermore, FEM simulations based on the non-orthogonal model showed similar final shapes and tendency of wrinkle formation with experimental results, and confirmed that wrinkles increase with less holding force and higher punch force is required under high frictional condition.

• Solar Energy
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• v.10 no.2
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• pp.10-17
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• 1990

Short-term tests were conducted on a house at KIER, Daejon for its thermal performance evaluation. The test procedure and data analysis were made according to the PSTAR method. Each test period was 3 days during which the building was unoccupied. The data measured with 8 channels were used to renormalize an audit based simulation model of the house. The following are the key parameters obtained in the present analysis: 1) the building loss coefficient(skin conductance plus infiltration conductance during coheating period); 2) the effective building heat capacity; and 3) the effective solar gain. An estimation of total heat required to maintain a standard level of comfort during a typical winter season is also calculated on the basis of the renormalized simulation model and typical long term weather data.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.432-436
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• 2015

This study computationally explored the thermal performance of passively-cooled polymer heat sinks utilizing seawater. Polymer heat sinks are proposed as cooling modules of the cold sides of thermoelectric generators for waste heat recovery. 3-D Computational Fluid Dynamics (CFD) modelling was conducted for a detailed numerical study. Polyphenylene sulfide (PPS) and pyrolytic graphite (PG) were selected for the base materials of polymer heat sinks. The computational study evaluated the performance of the PPS and PG heat sinks at various fin numbers and fin thicknesses. Their performances were compared with those of aluminum (Al) and titanium (Ti) heat sinks. The study results showed that the thermal performance of the PG heat sink was 3~4 times better than that of the Ti heat sink. This might be due mainly to the better heat spreading of the PG heat sink than the Ti heat sink. The effect of the number of fins on the performance of the PG heat sink was dissimilar to the cases of the PPS and Ti heat sinks. This result can be explained by the interrelationships among heat spreading, surface area enhancement, and fluidic resistance incorporating with an increase in the number of fins.

• Solar Energy
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• v.10 no.3
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• pp.19-26
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• 1990

Theoretical analysis for the thermal performance on the low-cost trickle collector, which is easy to manufacture and construct, has been performed. The results were in reasonably good agreement with those of the experiments. They have been applicable to predict long-term thermal performance on the low-cost solar collecting system. The dialogue type of computer program has been written based on the f-chart method and it can be used for designing a these collecting system, and investigating its economic feasibility.

• Journal of Korean Medical classics
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• v.18 no.4 s.31
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• pp.67-82
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• 2005

지구온난화(地球溫暖化), 식습관(食習慣), 주거환경여약물지오남용(住居環境與藥物之誤濫用), 공치기습열적체어체내(共致其濕熱積滯於體內), 소이유인음정부족이상화치성적병기(所以有因陰精不足而相火熾盛的病機), 기내용시여하(其內容是如下). 기일원인시지구온난화(其一原因是地球溫暖化), 차부단야기급성열성전염병(此不但惹起急性熱性傳染病), 이차야기음부족적허열성질환(而且惹起陰不足的虛熱 性疾患). 기이원인시식습관(其二原因是食習慣), 차적체습열이유발상화(此積滯濕熱而誘發相火), 차유발과도적양화작용(且誘發過度的陽化作用), 소이야기음부족적병기(所以惹起陰不足的病機). 기삼원인시주거환경(其三原因是住居環境), 차방기기적소통(此防其氣的疏通), 소이습열적체어체내이유발음부족적병기(所以濕熱積滯於體內而誘發陰不足的病機). 기사원인시약물적오남용(其四原因是藥物的誤濫用), 차치기열적잠복(此致其熱的潛伏), 소이유발음부족(所以誘發陰不足). 여차유발상화적현대환경(如此誘發相火的現代環境), 야기허열성질환(惹起虛熱性疾患). 소이증가태열여성인병(所以增加胎熱與成人病), 야취증가인과도적양화작용이불임질환(也就增加因過度的陽化作用而不姙疾患), 이차재정서적면(而且在情緖的面), 증가공격적여폭력적정서(增加攻擊的與暴力的情緖).

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.345-350
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• 2011

본 연구에서는 건축물의 초고층화와 대형화로 접목된 커튼월을 모델로 선정하여 알루미늄과 스틸 커튼월의 성능 비교를 위한 화재실험을 실시하였다. 화재실험은 $3m{\times}3m$ 규모의 알루미늄과 스틸 재질로 제작하여, 차염성, 차열성, 방열성, 변위, 커튼월 파괴를 측정하였다. 실험결과 알루미늄커튼월의 차염성은 12분, 차열성은 6분, 방열성은 26분을 기록하였고 스틸커튼월의 차염성은 10분, 차열성은 6분, 방열성은 14분을 기록하였다.

• The Journal of Korean Medicine
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• v.20 no.1 s.37
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• pp.1-10
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• 1999

한약(韓藥)의 효능(效能)은 약성(藥性)에 의해 분류(分類)되고 질병(疾病)을 치료(治療)하며 예방(豫防)하는 작용(作用)을 한다. 그러나 약성(藥性) 이론(理論)의 문헌(文獻)과 임상연구(臨床硏究)는 비교적 많지만 상대적으로 실험연구(實驗硏究)는 일부분에 불과하여 효능(效能)을 입증(立證)하는데 어려움이 많다. 이에 저자(著者)는 온열성약(溫熱性藥)들이 지니고 있는 유효(有效) 성분(成分)들을 조사(調査)하고 이 온열성약(溫熱性藥)에 함유(含有)되어 있는 유효(有效) 성분(成分)들의 구조적(構造的)인 특성(特性)과 화학적(化學的)인 공통점(共通點)을 찾아 온열성약(溫熱性藥)의 분류(分類)에 대한 일반적(一般的)인 기준(基準)을 제시(提示)하고자 하였다. 그 결과 각각의 열성약(熱性藥)과 온성약(溫性藥)들이 함유(含有)하고 있는 유효(有效) 성분(成分)간의 구조적(構造的)인 공통점(共通點)을 찾아내었으며 구조적(構造的)인 공통점(共通點)으로부터 다음과 같은 결론(結論)을 얻었다. 1. 열성약(熱性藥) 중에서 강(强)한 독성(毒性)을 나타내는 부자(附子)와 초오(草烏)의 효능을 나타내는 유효 성분(成分)들은 C19-diterpenoid alkaloid과 C20-diterpenoid alkaloid 계열의 구조(構造)를 지닌 화합물들로 구성(構成)되어 있다. 이 디테르펜 알카로이드(diterpene alkaloid)들의 경우 고리의 구조(構造)가 aconitane(1), hetisan(16)과 7,20-cycloveatchane(17)의 기본골격(基本骨格)을 지니고 있으며, 이 두 가지 기본구조(基本構造)의 공통점(共通點)은 A 고리에 질소를 포함한 2-azabicyclo-[3.3.1]-nonanyl의 부분구조를 갖고 있으며, 이 부분 구조는 자연계에 존재하는 tropane alkaloid들의 기본구조(基本構造)와 유사하다. Tropane alkaloid들은 중추신경계에 작용하는 약물들로 알려져 있으며, tropane alkaloid는 일반적으로 anatoxin a(171)와 같이 강(强)한 독성(毒性)을 나타내며, 부자(附子)와 초오(草烏)가 지니고 있는 강한 독성(毒性)은 바로 2-azabicyclo-[3.3.1]-nonanyl 구조(構造)에 기인하는 것으로 추정할 수 있다. 2. 육계(肉桂)에 주성분으로 함유(含有)되어 있는 cinncassiol(47) 화합물(化合物)들은 분자 내에 bicyclo-[4.3.0]-nonanyl과 bicyclo-[3.3.0]-octanyl의 기본 혹은 부분 구조를 지니고 있다. 3. Cinncassiol(47) 화합물(化合物)들은 강(强)한 항균력(抗菌力)을 보이고 있는데, cinncassiol(47) 화합물들이 지니고 있는 구조적인 특성인 bicyclo-[4.3.0]-nonanyl과 bicyclo-[3.3.0]-octanyl의 기본 혹은 부분 고리구조는 sesquiterpenoid 화합물(化合物)들과 diterpenoid 화합물(化合物)들 중에서 많이 발견되며, 이러한 구조(構造)를 지니고 있는 sesquiterpenoid 화합물(化合物)과 diterpenoid 화합물(化合物)들도 좋은 항균력(抗菌力)을 보이고 있다. 이러한 공통(共通)된 구조상(構造上)의 유사점(類似點)이 항균력(抗菌力)을 나타내는 지표로서 활용 가능성이 기대된다. 4. 온성약(溫性藥)의 경우, 백지(白芷)의 coumarin(39) 화합물(化合物)들과 furocoumarin(61) 화합물(化合物)들, 건량(乾量)의 gingerol(87), shogaol(93), gingerdiol(95) 등과 capsaicin(102), 마황(麻黃)의 ephedrine(124) 계렬(系列) 화합물(化合物)들, 세신(細辛)의 methyleugenol(136)과 asaricin(137)의 구조(構造)에서 발견(發見)할 수 있는 공통적(共通的)인 요소는 phenolic 또는 methoxyphenyl의 공통구조를 지니고 있다. 온성약(溫性藥)의 유효성분들은 공통적으로 phenolic aromatic 화합물(化合物)을 함유(含有)하고 있다. 따라서, 열성약(熱性藥)과 온성약(溫性藥)은 주성분(主成分)들의 분포(分布)가 각기 다르며, 독성(毒性)을 나타내는 열성약(熱性藥)은 2-azabicyclo-[3.3.1]-nonanyl 구조(構造)를 지니고 있고, 육계(肉桂)와 같은 항균력(抗菌力)을 지니는 약물(藥物)은 bicyclo-[3.3.0]-octanyl 또는 bicyclo-[4.3.0]-nonanyl의 구조(構造)를 지닌다. 백지(白芷), 마황(麻黃), 세신(細辛) 등에서 볼 수 있듯이 온성약(溫性藥)은 benzene 구조(構造)를 함유(含有)하는 phenolic aromatic 화합물(化合物)들이 주종을 이룬다.

• Clinical and Experimental Pediatrics
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• v.50 no.4
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• pp.376-380
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• 2007

Purpose : Febrile seizures occur in childhood associated with a febrile illness not caused by infections of the central nervous system. Provoked seizures are identified with seizures in association with infections that do not usually affect the brain such as gastroenteritis, except criteria for other febrile seizures in this study. We studied seizures provoked by minor extracranial infections, to contrast them with febrile and provoked seizures. Methods : We retrospectively studied one hundred and twenty children with provoked and febrile seizures who visited Chungbuk National University hospital from January, 2000 to December, 2004. Among these children, 36 patients were determined as provoked seizures and 84 patients as febrile seizures. We compared the distribution of minor infections between the patients with provoked seizures and those with febrile seizures, and studied risk factors of subsequent unprovoked seizures after febrile and provoked seizures associated with minor infections. Results : We analyzed the records of 120 children aged from 1 month to 15 years. The common etiologies of minor infections were gastroenteritis and respiratory infections. In the group of febrile seizures, there was a significantly greater proportion of patients with respiratory infections (58.3%) and a lesser proportion of those with gastroenteritis (25.0%). But there was a higher incidence of gastroenteritis (50.0%) in the provoked group. Comparing the distribution of etiologies between the patients with provoked seizures and those with febrile seizures seemed a significant difference. But, there were no difference between the provoked seizures and febrile seizures in the risk for subsequent unprovoked seizures. Conclusion : In conclusion, the leading cause except brain involvement is gastroenteritis in patients with provoked seizures, and respiratory infection in those with febrile seizures. Thus we need prompt recognition of, and medical attention given to, seizures associated with minor infections.

• Pediatric Infection and Vaccine
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• v.28 no.3
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• pp.144-148
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• 2021

Purpose: Nonpharmaceutical measures, such as social distancing, have resulted in unintended consequences, including a decrease in the incidence of childhood diseases. This study aimed to estimate the impact of social distancing on the incidence of febrile seizure (FS) in Korea using nationally representative data. Methods: We used claims data from the Health Insurance Review and Assessment Service, a single-payer database capturing >95% of the Korean population. The database included any inpatient encounter with a FS diagnosis from January 2010 to September 2020 for those aged 0-5 years old. We aggregated the monthly number of cases to estimate the incidence per 100,000 patient-years in 2020 (January 1 to September 30) for the same periods in 2010-2019. Results: The incidence of FS in 2020 ranged from 113 per 100,000 (95% confidence interval [CI], 108-118 per 100,000) in January to 27 per 100,000 (95% CI, 25-30 per 100,000) in September, whereas the average FS incidence in 2010-2019 ranged from 116 per 100,000 (95% CI, 112-121 per 100,000) in January to 101 per 100,000 (95% CI, 97-106 per 100,000) in September. Conclusions: The incidence of FS decreased by -38% in 2020, suggesting that social distancing contributed towards decreasing the incidence of FS.