http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Critical Factors Affecting Biological Phosphorus Removal in Dairy Wastewater Treatment Plants
안창훈,Jae Kwang Park 대한토목학회 2008 KSCE JOURNAL OF CIVIL ENGINEERING Vol.12 No.2
Operational data from nine dairy wastewater plants (DWTPs) in Wisconsin were collected and analyzed to determine reasons forpoor enhanced biological phosphorus removal (EBPR) efficiency. Several factors affecting EBPR performances in dairy wereidentified. Since many dairies operate five days a week, DWTPs suffer low F/M ratios during off-days, leading to sludge bulking andunstable EBPR efficiency. The most pronounced factor affecting EBPR performance was uneven organic loading caused by lack ofan equalization tank or too a small volume to alleviate the fluctuation in flow and organic loading. The other factor was imbalance ofnutrients, especially nitrogen. The other factors include sudden change of pH in a matter of hours and higher temperature (> 30C) inthe summer. The high temperature was thought to shift microbial population and thus lead to the loss of EBPR capability.Unexpected discharge of cleaning solution was another problem causing poor EBPR and COD removal efficiencies. Laboratory-scale tests confirmed the effects of the COD/P ratio (organic loading) and pH on EBPR efficiency. Microscopic examination showedthe presence of tetrad-arranged cocoid cells, called G-bacteria in five out of nine DWTPs. Rhodocyclus-related PAOs were alsodetected from Fluorescent in situ hybridization (FISH) analysis.
Clinical characteristics of hypertensive encephalopathy in pediatric patients
안창훈,한승아,공영화,김선준 대한소아청소년과학회 2017 Clinical and Experimental Pediatrics (CEP) Vol.60 No.8
Purpose: The aim of this study was to assess the clinical characteristics of hypertensive encephalopathy according to the underlying etiologies in children. Methods: We retrospectively evaluated 33 pediatric patients who were diagnosed as having hypertensive encephalopathy in Chonbuk National University Children’s Hospital. Among the patients, 18 were excluded because of incomplete data or because brain magnetic resonance imaging (MRI) was not performed. Finally, 17 patients were enrolled and divided into a renal-origin hypertension group and a non–renalorigin hypertension group according to the underlying cause. We compared the clinical features and brain MRI findings between the 2 groups. Results: The renal group included renal artery stenosis (4), acute poststreptococcal glomerulonephritis (2), lupus nephritis (2), and acute renal failure (1); the nonrenal group included essential hypertension (4), pheochromocytoma (2), thyrotoxicosis (1), and acute promyelocytic leukemia (1). The mean systolic blood pressure of the renal group (172.5±36.9 mmHg) was higher than that of the nonrenal group (137.1±11.1 mmHg, P<0.05). Seizure was the most common neurologic symptom, especially in the renal group (P<0.05). Posterior reversible encephalopathy syndrome (PRES), which is the most typical finding of hypertensive encephalopathy, was found predominantly in the renal group as compared with the nonrenal group (66.6% vs. 12.5%, P<0.05). Conclusion: We conclude that the patients with renal-origin hypertension had a more severe clinical course than those with non–renal-origin hypertension. Furthermore, the renal-origin group was highly associated with PRES on brain MRI.
안창훈 한국보안관리학회(구 한국경호경비학회) 2002 시큐리티연구 Vol.- No.5
Koreans are the most avid Internet surfers in the world according to Nielson/NetRatings(Reuters, August 2001) and most Internet connections are made through high-speed connections like Digital Subscriber Lines (DSLs). The result of such internet fervor is a nation that is fertile in both hackers and software companies(over 200 in the field of network security alone). However, by-product of Internet activity is cyber crime and the need to protect innocent users from the dangers of cyber criminals and cyber-terrorists be they are individuals or organized groups. Hence the Cyber Terror Response Team (CTRT) was organized in late 2000 with the mandate to fulfill that role. In these contexts, this study analyzes the actual conditions of cyber terror and suggests the countermeasures against cyber terror in Korea.
산, 염기 촉매 하에서의 polymethylsilsesquioxane의 분자량 조절
안창훈,석상일,진문영 한국공업화학회 2001 한국공업화학회 연구논문 초록집 Vol.2001 No.-
유-무기 하이브리드 재료로 많은 연구의 대상이 되어온 다양한 구조의 polysilsequoxane은 유전율이 낮고 내열성이 우수하여 차세대 고집적 반도체용 저 유전율 층간 절연막 재료로 새롭게 부각되고 있다. Polymethylsilsesquioxane(PMSSQ)은 주로 가수분해-축중합 반응을 이용하는 소위 졸-겔법으로 합성되고 있다. 이때 가수 분해를 위한 물의 첨가량, 가수분해-축증합 반응 촉진을 위한 촉매의 종류 및 양에 따라 PMSSQ의 특성이 달라지고 있다. 본 연구에서는 실리콘 기판에서의 코팅 특성과 유전율을 고려한 코팅 용액의 설계를 위하여 다양한 범위의 분자량 및 분포를 가진 PMSSQ를 산 혹은 염기 촉매 하에서 합성하였다. Methyltrimethoxysilane 혹은 methyltriethoxysilane을 출발 원료로 물의 양, 촉매의 양 반응 시간에 따른 PMSSQ의 분자량의 변화를 GPC로 분석하였다. 산 혹은 염기 촉매 및 반응 조건에 따른 PMSSQ의 구조적 차이 및 화학적 결합 환경을 TGA, FT-IR, <sup>29</sup>Si-NMR, <sup>13</sup>C-NMR 등으로 조사하였다.
Dimethylsiloxane이 도입된 PMSSQ의 졸-겔 제조와 코팅막의 특성
안창훈,석상일,진문영,강영구,이창진 한국공업화학회 2002 한국공업화학회 연구논문 초록집 Vol.2002 No.0
PMSSQ(polymethylsilsesquioxane)은 유전율이 낮고 내열성이 우수하여 차세대 고집적 반도체용 저 유전율 층간 절연막 재료로 연구되고 있지만, 기계적 취성이 낮은 문제점이 있다. PMSSQ는 주로 가수분해-축 중합 반응을 이용하는 소위 졸-겔법으로 합성되어지므로 물의 첨가량, 촉매의 종류와 양, 모노어의 농도에 따라 국부적인 결합구조및 특성이 달라진다. 본 연구에서는 저 유전율 절연막으로써 PMSSQ의 장점을 유지하면서 기계적 취성을 개선하기위한 목적으로 dimethylsiloxane과 공중합된 PMSSQ를 촉매 없이 졸-겔 방법으로 합성하는 방법에 대하여 보고하고자 한다. 합성된 공중합 PMSSQ의 분자량은 GPC로, 화학적 결합환경에 대하서는 FT-IR, 29Si-NMR 등으로 분석하였다. 합성된 공중합 PMSSQ를 MIBK 등의 유기 용매에 용해하여 스핀 코팅법으로 실리콘 웨이퍼에 코팅하고 약 430°C에서 경화한 후, 코팅막의 특성에 대하여 논의하였다.