Coating with boron nitride on SiC fiber using atomic substitution

Woo‑Seong Tak,Jin‑Uk Hwang,Young‑Keun Jeong,Woo‑Sik Kim 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.2

To increase the mechanical properties of ceramic matrix composite, it is important that formation of lubricant layer for crack deflection between matrix and fiber. Therefore, we fabricated uniform boron nitride (BN) lubricant layer using atomic substitution method. Silicon carbide (SiC) fiber surface was modified with amine groups using (3-amonipropyl)triethoxysilane to coat SiC fiber with BN as a solid lubricant. Then, surface was coated with graphene oxide (GO). Boric acid powder was supplied to the GO-coated fibers and the samples were heat-treated at 1200–1400 ℃ under N2 and NH3 atmospheres. An uniform BN layer could be coated on SiC fiber with 10 nm-1.11 μm. Crystallinity and thickness of BN layer could be controlled by reaction temperature. It was also confirmed that crystalline BN formed under process conditions of higher than 1400 ℃.

DAX-1 acts as a novel corepressor of orphan nuclear receptor HNF4alpha and negatively regulates gluconeogenic enzyme gene expression.

Nedumaran, Balachandar,Hong, Sungpyo,Xie, Yuan-Bin,Kim, Yong-Hoon,Seo, Woo-Young,Lee, Min-Woo,Lee, Chul Ho,Koo, Seung-Hoi,Choi, Hueng-Sik American Society for Biochemistry and Molecular Bi 2009 The Journal of biological chemistry Vol.284 No.40

<P>DAX-1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor family and acts as a corepressor of a number of nuclear receptors. HNF4alpha (hepatocyte nuclear factor 4alpha) is a liver-enriched transcription factor that controls the expression of a variety of genes involved in cholesterol, fatty acid, and glucose metabolism. Here we show that DAX-1 inhibits transcriptional activity of HNF4alpha and modulates hepatic gluconeogenic gene expression. Hepatic DAX-1 expression is increased by insulin and SIK1 (salt-inducible kinase 1), whereas it is decreased in high fat diet-fed and diabetic mice. Coimmunoprecipitation assay from mouse liver samples depicts that endogenous DAX-1 interacts with HNF4alpha in vivo. In vivo chromatin immunoprecipitation assay affirms that the recruitment of DAX-1 on the phosphoenolpyruvate carboxykinase (PEPCK) gene promoter is inversely correlated with the recruitment of PGC-1alpha and HNF4alpha under fasting and refeeding, showing that DAX-1 could compete with the coactivator PGC-1alpha for binding to HNF4alpha. Adenovirus-mediated expression of DAX-1 decreased both HNF4alpha- and forskolin-mediated gluconeogenic gene expressions. In addition, knockdown of DAX-1 partially reverses the insulin-mediated inhibition of gluconeogenic gene expression in primary hepatocytes. Finally, DAX-1 inhibits PEPCK and glucose-6-phosphatase gene expression and significantly lowers fasting blood glucose level in high fat diet-fed mice, suggesting that DAX-1 can modulate hepatic gluconeogenesis in vivo. Overall, this study demonstrates that DAX-1 acts as a corepressor of HNF4alpha to negatively regulate hepatic gluconeogenic gene expression in liver.</P>

저비용 우량봉지종균 생산기술 개발

조우식 외 한국버섯학회 2010 한국버섯학회지 Vol.8 No.1

느타리버섯 재배시 현재 톱밥병종균을 대체할 수 있는 저비용 우량봉지제조기술을 개발하기위해 시험을 수행한 결과는 다음과 같다. 1. 재료의 산도 (pH)는 포플러톱밥이 pH 6.7, 미강은 pH 6.4에 비하여 비트펄프는 pH 4.9로 다른 배지재료에 비하여 산성을 나타내었다. T-C는 포플러톱밥 57.5%, 면실피 54.5%, 미강 52.4%로 나타났고, T-N는 포플러톱밥이 0.1%로 면실피 1.77%, 미강 0.94%로 나타났다. 2. 균사생장정도는 신농73호 2.5kg 규격 종균의 필터가 구비된 종균의 경우 15.7cm, 마개형 10.5cm, 필터가 없는 종균은 7.5cm로 필터구비종균이 생장이 우수하였고, 균사밀도의 경우에도 필터형이 밀도가 높았다. CO₂ 농도는 신농73호 2.5kg 규격 종균의 필터가 구비된 종균의 경우 1,400ppm, 마개형 2,200ppm, 필터가 없는 종균은 3,200ppm 로 필터구비종균이 농도가 낮음을 알 수 있다. 3. 배양소요일수를 측정한 결과, 신농 73호에서 2.5㎏ 필터종균의 경우 18일, 마개필터 18일, 필터가 없는 처리는 19일로 큰 차이는 없었다. 생산량의 경우 신농73호에서 2.5㎏ 필터종균의 경우 118g, 마개필터 112g, 필터가 없는 처리는 100g으로 필터처리 종균이 생산력 측면에서 우수하였다. The word spawn is derived from an old French verb, espandre, meaning to spread out or expand. Spawn is also defined as "the mycelium of fungi, especially of mushrooms grown to be eaten, used for propagation." The effects of bag spawn to sawdust substrate on the growth of Pleurotus ostreatus were conducted. The duration of mycelial growth and days of pinhead formation of bag spawn(2.5kg) were 18~19days and 7~8days, whereas bottle spawn (1,000㎖) was 18days and 6days, respectively. The yield of mushroom fruitbody was that bag spawn is 100~118g, bottle spawn is 95~115g. In economical analysis, bag spawn is increased to 50%, compared to bottle spawn in relative income.The word spawn is derived from an old French verb, espandre, meaning to spread out or expand. Spawn is also defined as "the mycelium of fungi, especially of mushrooms grown to be eaten, used for propagation." The effects of bag spawn to sawdust substrate on the growth of Pleurotus ostreatus were conducted. The duration of mycelial growth and days of pinhead formation of bag spawn(2.5kg) were 18~19days and 7~8days, whereas bottle spawn (1,000㎖) was 18days and 6days, respectively. The yield of mushroom fruitbody was that bag spawn is 100~118g, bottle spawn is 95~115g. In economical analysis, bag spawn is increased to 50%, compared to bottle spawn in relative income.

점액성 대장 및 직장암의 임상 병리학적 고찰

신동우,김남규,민진식,김호근,양우익 대한대장항문학회 1997 Annals of Coloproctolgy Vol.13 No.3

버섯산업에 대한 2008년 국민의식조사

조우식 외 한국버섯학회 2009 한국버섯학회지 Vol.7 No.1

Gyeongbuk Agricultural Technology Administration carried out the nation opinion research to mushroom industry in 115 of the citizen and the provincials from 10/17/2008 to 10/18/2008. Which was for both grasping the citizen's opinion and habits and understanding farmers'. The result of the research is the following. 37.4 percent people preferred Lentimus edodes among the all respondents and 27.0 percent preferred Flammulina velutipes. As for the purchasing place, 57.4 percent buy them in large retail stores, 40.9 percent buy them in traditional markets. 67 percent of the respondents mainly use them in fall, 31.3 percent use them in winter. 88.7 percent of them mainly eat the mushrooms at home, 11.3 percent is at restaurants. 63.5 percent of them responded that the price of mushrooms was resonable, 26.1 percent answered that was expensive. In appearance, 27 percent of them chose yellow Flammulina velutipes as a good-looking mushroom, 19.1 percent chose Lentimus edodes. 버섯산업의 활성화 자료를 제공하고, 정책수요를 발굴하기 위해 버섯산업에 대한 국민의식조사를 실시한 결과를 요약하면 다음과 같다. 가. 전체 응답자 중 37.4%가 표고, 27.0%가 팽이, 16.5%가 느타리라고 응답한 반면, 6.1%가 영지버섯, 8.7%가 상황버섯이라고 응답한 것으로 볼 때 대중화된 식용버섯을 식용으로 선호하였다. 나. 57.4%가 대형마트, 40.9%가 재래시장이라고 응답한 반면, 2.6%가 백화점, 5.2%가 소매점이라고 응답한 것으로 볼 때 대부분의 버섯소매유통이 대형마트와 재래시장에서 이뤄지고 있다. 다. 67%가 가을, 31.3%가 겨울이라고 응답한 반면, 20.9%가 봄, 22.6%가 여름이라고 응답한 것으로 볼 때 가을철에 많은 비중이 소비되지만 봄, 여름철에도 적지 않은 양이 소비되는 것을 알 수 있으며 버섯은 연중 소비되는 농산물로 인식하고 있다. 라. 88.7%가 가정집, 11.3%가 식당이라고 응답한 반면, 1.76%만이 야외라고 응답한 것으로 볼 때 가정주부들을 대상으로 한 소규모의 포장기술개발 및 식당에서의 소비촉진을 위한 홍보를 강화할 필요성이 있다고 생각된다. 마. 63.5%가 보통이다, 26.1%가 비싸다고 응답한 반면, 2.6%가 매우 비싸다, 4.3%가 싸다, 1.7%가 매우 싸다고 응답한 것으로 볼 때 현재의 버섯가격은 보통이라고 인식하고 있다. 바. 27.0%가 황금팽이, 19.1%가 표고, 16.5%가 영지라고 응답한 반면, 2.6%가 만가닥버섯, 7%가 목이버섯, 새송이가 10.4%라고 응답한 것으로 볼 때 유색의 버섯을 관상용으로 선호하며, 무채색의 버섯 및 아직 대중화되지 않은 버섯은 관상용으로 선호하지 않음을 알수 있다.

소비촉진을 위한 가정재배용 버섯키트개발 연구

조우식 외 한국버섯학회 2007 한국버섯학회지 Vol.5 No.1

버섯산업의 활성화자료 제공과 버섯의 가정내 재배·학생들의 과학탐구용으로 사용키위해서 일반 가정주택의 실내에서 버섯류 재배가능성 검토의 일환으로 수행한 실험의 결과를 요약하면 다음과 같다. 가. 가정내 각실별 온·습도 측정결과는 세면실에서 64∼72%, 온도 20.2∼26.0℃로 상대적으로 거실, 부엌등 타실보다 버섯생육에 유리한 조건을 나타내었다 (1999. 4. 25∼7. 25). 나. 느타리버섯 상자재배에서 세면실의 경우 초발이소요일수는 3일, 수량은 2,060g, 회수율은 90%였다. 다. 느타리버섯 봉지볏짚재배에서 세면실의 경우 초발이소요일수는 2일, 수량은 90g, 회수율은 153%였다. 라. 느타리버섯 봉지톱밥재배에서 세면실의 경우 초발이소요일수는 4일, 수량은 770g, 회수율은 89%였다. 마. 영지버섯 봉지톱밥재배에서 세면실의 경우 초발이소요일수는 11일, 수량은 172g, 회수율은 16%, 중량감소율은 61%로 나타났다. 바. 본시험에서 수행한 4처리 모두 거실, 침실, 부엌에 비해 세면실에서의 생산된 버섯의 수량이 우수하였다. 사. 본 실험의 결과를 일부 기술하여 "내손으로 재배하는 가정버섯 효능과 활용법"이란 제목의 책자를 공동저술하였다 (장 등, 2003). This study for establishment of cultivation technique was carried out in home, Pleurotus ostreatus, Ganoderma lucidum. The mushroom kit allows you to grow some of the mushrooms used by the finest chefs in the world easily and quickly almost anywhere in your own home or office. Mushroom kits may be placed on a coffee table, counter, or desk. They will produce mushrooms virtually anywhere room temperature is maintained. Now we have the opportunity not only to enjoy watching these exotic mushrooms grow but also to enjoy eating the freshest organic mushrooms possible. To study for the possibility of indoor cultivation of P. ostreatus, and G. lucidum, we invested cultivation status with two kinds of sawdust, cotton waste and rice straw in washroom, kitchen, living room, and bedroom. It took 2∼4 days to make primordia formation in a block of P. ostreatus, and G. lucidum was 11 days. Weight of P. ostreatus on cotton waste, rice straw, and willow sawdust were 2,060g, 90g, and 770g, respectively. and weight of G. lucidum on oak sawdust was 172g. Th best result was achieved in washroom, among used washroom, kitchen, living room, and bedroom.

Penicillium rubrum에 의한 상황버섯 (Phellinus baumii) 푸른곰팡이병의 발생

조우식 외 한국버섯학회 2007 한국버섯학회지 Vol.5 No.1

본 연구에서는 상황버섯 (P. baumii)의 자실체에 발생하는 Penicillium sp.균을 동정하기 위하여, 분리균의 배양적·형태적 특징을 조사하였다. 분리된 Penicillium sp.의 형태적 특성을 조사한 결과, 분생포자의 모양은 타원형이고 직경이 1.8∼2.3 ㎛ 크기로 분생포자를 많이 형성하였다. 분생포자경은 균사로부터 one-stage branch 모양을 형성하였고, matulae는 3∼5개로 길이가 5.2∼7.8 ㎛이며, phialide는 플라스크상이고 크기가 5.7∼7.5×2.2∼2.7 ㎛이였다. Czapek's agar 배지에서 생육시 25℃에서 8일간 균체가 23 ㎜ 생장하였다. PDA 배지 상에서 균총의 형태는 처음에는 조밀한 솜털모양의 백색을 띄었으며 차츰 기중균사가 형성되었고, 점차 회녹색으로 변하였다. 이상과 같은 형태 및 배양적 특징으로 이 균을 P. rubrum으로 동정하였다. 상황버섯 (P. baumii)에서 P. rubrum에 의한 병은 아직 국내에 보고된바 없어, P. rubrum에 의한 상황버섯 (P. baumii) 푸른곰팡이병을 최초로 보고한다. Green mold of Phellinus baumii mushroom caused by a species of Penicillium was observed in Daegu on August, 2000. The causal fungus was identified as Penicillium rubrum based on its cultural and morphological characteristics. Conidiophores of the fungus were one-stage branched and terminating in a whorl of 3∼5 metulae. The metulae were mostly 5.2∼7.8 ㎛ in size. Phialides were flask-shaped and 5.7∼7.5×2.2∼2.7 ㎛. Conidia were subglobose and 1.8∼2.3 ㎛. Colonies on Czapek's agar growing, attaining a diameter of 23 ㎜ within 8 days at 25℃. The optimum temperature for growth of the fungus was about 20∼30℃. This is the first report on the occurrence of green mold of P. baumii caused by P. rubrum in Korea.

미세결정립 Fe-C 합금의 초소성

우성식,김영로,김우진 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.1

Tensile elongation behavior of fine-grained Fe-C alloys has been investigated as a function of cementite volume fraction, degree of microstructural refinement or Zener-Hollomon parameter. Creep strength of Fe-C alloys is compared to be similar when grain size is similar. Room-temperature strength, however, turned out to be quite different, depending on the volume of cementite. Tensile ductility of ingot-processed alloys increases with carbon content (cementite volume fraction of cementite) but starts to decrease after 2.1%. Tensile ductility of Fe-C alloys with carbon content higher than 2.1% can be significantly enhanced when powder-processing routes are utilized instead of ingot-processing routes. Tensile elongation behavior of cementite-based alloys is revealed to be different from that of iron-based alloys when compared as a function of Zener-Hollomon parameter.

분절호선법으로 상하악 절치부 압하 시 순측경사도가 미치는 영향에 관한 3차원 유한요소법적 연구

김동우,양훈철,김기태,김성식,손우성 대한치과교정학회 2003 대한치과교정학회지 Vol.33 No.4

본 연구는 상하악 절치부의 압하를 도모하기 위한 장치의 하나인 분절호선장치를 사용하여 절치부의 순측경사에 따른 저항중심의 위치와 변화양상, 그리고 치축경사 개선과 압하를 동시에 이루기 위해 필요한 최소 후방 견인력의 크기 및 변화양상을 알아보기 위하여 3차원 유한요소법을 이용하여 시행되었으며 다음과 같은 결론을 얻었다. 1. 치축 경사도의 변화에 따른 상악 절치부 저항중심은 1) 정상 치축경사를 가진 경우에서 측절치 브라켓 원심면 후방 6mm에 위치하였다. 2) 순측경사가 10˚ 증가된 경우에서 측절치 브라켓의 원심면 후방 9mm에 위치하였다. 3) 순측경사가 20˚ 증가된 경우에서 측절치 브라켓 원심면 후방 12mm에 위치하였다. 4) 순측경사가 30˚ 증가된 경우에서 측절치 브라켓 원심면 후방 16mm에 위치하였다. 2. 치축 경사도의 변화에 따른 하악 절치부 저항중심은 1) 정상 치축경사를 가진 경우에서 측절치 브라켓 원심면 후방 10mm에 위치하였다. 2) 순측경사가 10˚ 증가된 경우에서 측절치 브라켓 원심면 후방 13mm에 위치하였다. 3) 순측경사가 20˚ 증가된 경우에서 측절치 브라켓 원심면 후방 15mm에 위치하였다. 4) 순측경사가 30˚ 증가된 경우에서 측절치 브라켓 원심면 후방 18mm에 위치하였다. 3. 응력 분포 양상은 1) 각 저항중심에서 압하력을 가한 경우에 치주인대에 균일한 압축응력을 나타내었다. 2) 후방 견인력을 동시에 적용한 경우에 순측경사가 증가할수록 응력분포 양상이 복잡해지는 양상을 보였다. 4. 상하악 절치부가 20˚까지 순측경사된 경우에서 pure intrusion을 위하여 필요한 후방 견인력의 크기도 증가하였다. This study was designed to investigate the position of anteroposterior center of resistance for genuine intrusion and the mode of change of the minimum distal force for simultanous intrusion and retraction of the upper and lower incisors according to the increase of labial inclination. For this purpose, we used the three-piece intrusion arch appliance and three-dimensional finite element models of upper and lower incisors. 1. Positions of the center of resistance in upper incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 6mm behind the distal surface of the lateral incisor bracket. 2) In 10˚ increase of the labial inclination situation, the center of resistance was located in 9mm behind the distal surface of the lateral incisor bracket. 3) In 20˚ increase of the labial inclination situation, the center of resistance was located in 12m behind the distal surface of the lateral incisor bracket. 4) In 30˚ increase of the labial inclination situation, the center of resistance was located in 16m behind the distal surface of the lateral incisor bracket. 2. Positions of the center of resistance in lower incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 10mm behind the distal surface of the lateral incisor bracket. 2) In 10˚ increase of the labial inclination situation, the center of resistance was located in 13mm behind the distal surface of the lateral incisor bracket. 3) In 20˚ increase of the labial inclination situation, the center of resistance was located in 15m behind the distal surface of the lateral incisor bracket. 4) In 30˚ increase of the labial inclination situation, the center of resistance was located in 18m behind the distal surface of the lateral incisor bracket. 3. The patterns of stress distribution were as follows; 1) There were even compressive stresses in and periodontal ligament when intrusion force was applied through determined center of resistance. 2) There were gradual increase of complexity in compressive stress distribution pattern with increase of the labial inclination when intrusion and retraction force were applied simultaneously. 4. With increase of the labial inclination of the upper and lower incisors, the position of the center of resistance moved posteriorly. And the distal force for pure intrusion was increased until 20˚ increase of the labial inclination.

相變化物質을 利用한 열저장계의 說計變數에 關한 硏究(Ⅰ)

金雨植,宋熙烈,金鳳滿 연세대학교 산업기술연구소 1980 논문집 Vol.12 No.1

This investigation was performed to determine the changes in the type of energy extraction by the shift of the temperature and flowrate of the input air in the heat supplying system of a phase change material-heat storage system. For the phase change material. Na₂SO₄10H₂O was used and by changing the temperature and flowrate of the input air, the different wall temperatures(T??) and the temperatures at the center of the cylinder(T?) were recorded. Thus the changes in surface heat flux as a function of time of latent heat output was obtained. The result reveals that when the temperature of input air is constant. the freezing time of Na₂SO₄·10H₂O is inversely proportional to the flow rate of air with the slope of 0.39 in the log-log coordinate and when the flow rate of air is const, ant the freezing time of Na₂So₄.10H₂O is proportional to the input air with the slope of 1.84 in the log-log coordinate. Another conclusion is that the flow rate of the input air had a markedly influence than the temperature on affecting the type of energy extraction.