알칼리 전해액의 상호작용에 의한 Stainless Steel 주성분의 변화 분석

변창섭,임수곤,김수곤,최호상,신훈규,Byun, Chang-Sub,Lim, Soo-Gon,Kim, Su-Kon,Choi, Ho-Sang,Shin, Hoon-Kyu 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.7

In this paper, We studied the change of surface and variation of elements on both electrodes of hydrogen generator of alkaline electrolysis in use of FE-SEM and SIMS. We used the stainless steel 316(600 ${\mu}m$) as electrode in condition of 25%KOH, $60^{\circ}C$ Temperature. The results show that the intensity of elements (C, Si, P, S, Ti, Cr, Mn, Fe, Ni, Mo) of Positive Electrode are decreased as much as about $10^1{\sim}10^3 $than the original electrode. Thickness of Positive Electrode is decreased about 40 ${\mu}m$ after chemical reaction. The negative electrode, however, shows a slight variation in the intensity of elements (C, Si, P, Fe, Ni, Mn, Mo) but Change of thickness and surface' shape of electrode show nothing after chemical reaction. The change in thickness and variation of Stainless Steel 316 cause the lifetime of electrode to be shorted. We also observed hydrogen, oxygen, potassium in both electrodes. Especially, The potassium is increased in proportional with depth of positive electrode. this means the concentration of alkali solutions is changed. and so we have to supply alkaline solution to generator in order to produce same quantity of hydrogen gas continuously. we hope that this study gives a foundation to develop the electrode for hydrogen generator of alkaline electrolysis.

가교량의 온도응력 평가

박영훈,이승용,변윤주,장동일,Park, Young Hoon,Lee, Seung Yong,Byun, Yun Joo,Chang, Dong Il 한국강구조학회 1998 韓國鋼構造學會 論文集 Vol.10 No.1

교량의 신설 또는 보수를 위한 작업차량의 진출입로나 기존 통행차량의 우회를 목적으로 한시적으로 사용되는 가교량은 일반적으로 상부구조로 H-Beam, 하부구조로 H-Pile을 사용하여, 이들 각 부재를 고장력볼트로 연결한 강구조 형식을 채택하고 있다. 그러나 이러한 교량은 상부구조에 신축이음부를 두지 않고 있어 일일기온차에 의해 발생하는 온도응력이 전체 구조거동에 미치는 영향이 클 것으로 예상된다. 따라서, 본 연구에서는 상부구조인 H-Beam에 온도와 변형률의 상시계측을 위한 모니터링 시스템을 도입하여 측정된 온도 및 변형률 데이터로부터 발생온도와 온도응력의 관계를 조사하였으며, 구조해석을 통한 이론치와의 비교를 실시하여 각 부재에서 발생하는 온도응력이 전체 구조거동에 미치는 영향을 평가하였다. 그 결과, 본 구조물에서 발생하는 응력의 변화는 부재의 온도변화에 의한 온도응력이 주원인인 것으로 나타났으며, 하부구조인 H-Pile의 충분한 교축방향 변위로 인하여 상부구조인 H-Beam의 온도변형 구속은 이루어지지 않는 것으로 나타났다. 한편, 상부구조인 H-Beam간의 연결 강성이 충분하지 않아 전체 구조계보다는 부분 구조계에 대한 해석으로부터 얻어진 변형량이 측정 온도 및 응력으로부터 계산된 변형량과 잘 일치하는 것으로 나타났다. The temporary steel bridges which are constructed for detour and constructional expediency are consisted of H-beams(as superstructure) and H-piles(as substructure). Because these members are fastened by high-tension bolts, there are no expansion joints in these bridges. So, these kinds of bridges have no system which can relieve the excessive thermal stress. In this investigation, monitoring system was set up at temporary steel bridge and stress and temperature changes of H-beam are monitored. From these measured data, it is analyzed that the relationship between ambient and main-girder temperature change, between temperature and stress change. With these analyses, it is resulted that the thermal stress take main part of stress variation in this bridge and the restrain of thermal longitudinal displacement of H-pile. In addition, because the connection part of H-beam to H-beam is weak in the continuous spans, the sub-modelling is well apt to reflect the effect of thermal stress.

한국인 A 형 간염 환자에서 A 형 간염 바이러스의 유전자형에 관한 연구

권오상,송기준,박상훈,송진원,김재선,김종헌,변관수,이창홍,연종은,백락주,박영태 대한간학회 2000 Clinical and Molecular Hepatology(대한간학회지) Vol.6 No.3

$quot;목적: 한국에서 과거 A형 간염은 낙후된 개인위생 및 자연환경으로 유소아기에 불현성 감염으로 앓고 지나가게 되어 청소년 및 성인에서 HAV에 대한 항체 보유율이 매우 높고 성인에서의 급성 A형 간염은 매우 드물게 보고되었다. 그러나 고도의 경제성장과 더불어 식생활, 위생상태의 개선, 상하수도의 보급 등으로 유소아기의 A형 간염 이환율이 현격히 감소하면서 청소년 및 성인에서 HAV 항체가 없는 인구집단 즉 HAV에 감염되면 현증 간염이 발생할 수 있는 인구 집단이 증가되어 최근 수 년 사이에 현증 A형 간염이 폭발적으로 증가하게 되었다. 이에 저자는 HAV의 유전자형을 알아보고 이미 보고된 각국의 HAV와 연관성을 알아보고자 본 연구를 시행하였다. 대상과 방법: 1994년부터 1998년까지 한국에서 산발적으로 발생한 18예의 A형 간염 환자의 혈청에서 HAV RNA를 추출, 역전사-중화효소 연쇄반응법(RT-PCR)으로 증폭하여 직접 염기서열의 분석을 통해 국내 HAV 사이에 염기서열, 아미노산의 차이 등을 알아보고 세계 각국에서 보고되었던 HAV 분리주들과 비교하였다. 결과: HAV 게놈의 특정부위인 VP1/2A 연결부위 168 bp 길이에서 시행한 염기서열 분석 결과 한국에서 분리된 18예의 HA이러스는 최근 해외에서 유입된 바이러스일 가능성은 적으며 따라서 장기간 국내에서 토착화된 바이러스일 것으로 생각된다. $quot;Background/Aims: Studies of genotypes and changes in nucleotide and amino acid sequences of hepatitis A virus (HAV) may provide valuable information on the epidemiological aspects of a particular region. In Korea the prevalence of anti-HAV in the 1 - 20 year age group declined from 60% in 1980 to 9% in 1995. As a result this age group has a high risk of HAV infection. Actually over 1,500 cases of clinically overt hepatitis A occurred in 1998 while few cases of clinical hepatitis A had been reported until the early 1990s. The aims of this study are to determine the genotypes of HAV which have been circulating in Korea and to define the phylogenetic relationships of geographically defined isolates. Method: From 1994 - 1998 a total of 18 serum specimens was obtained from patients in Korea with sporadic form acute hepatitis A. The HAV nucleic acid from serum specimens was subjected to genomic sequence analysis following viral RNA extraction, reverse transcription and amplification of the cDNA by PCR. DNA sequencing was performed in both directions of each PCR product. Results: All isolates clustered within the subgenotype IA irrespective of the geographic locations and timing of the clinical hepatitis. Among 18 Korean isolates, 9 isolates had 2 amino acid sequence changes and 2 isolates had 1 amino acid sequence change. These changes in the amino acid sequences are unique and have never been reported in HAV subgenotype IA. Conclusions: All isolated HAV had genotype (IA). Eleven of 18 isolates had unique changes in amino acid sequences. These data indicate that the endemic HAV has been circulating in Korea over a long period of time.

철근콘크리트 휨部材의 回轉能力에 對한 實驗的 基礎 硏究

邊根周,임창희,한상훈 연세대학교 산업기술연구소 1980 논문집 Vol.12 No.1

Plastic analysis of concrete indeterminate structures is based on rotation capacity of the plastic hinges. Improved rotation capacity of the hinges permits better distribution of moments and higher reserve strength of structural systems. Consequently, maximum ductility resulting in maximum rotation capability of the plastic hinges is necessary. This study is no analyse experimentically the total rotation capacity (elastic rotation+plastic rotation) of reinforced concrete simple beams subject to a transverse load at midspan. The test results examined herein indicate that the plastic-hinge rotations of simple rectangular beams,computed on the basis of a formula derived,compared well with experimentally observed hinge rotations. Therefore, the total rotation capacity in the plastic hinge stage of reinforced concrete beams without stirrup can be predicted from the formular developed. Even if research properties were properly ordered and the appropriate model chosen, extensive long-term experimentation would be necessary for any substantial improvement in our knowledge.

고콜레스테롤 혈증 환자에서 Cerivastatin(LIPOBAY, 의과학연구소)의 임상효과 및 안전성에 관한 연구

박성훈,김미연,정수진,이영숙,박창한,변은경,전성희 梨花女子大學校 醫科大學 醫科學硏究所 2001 EMJ (Ewha medical journal) Vol.24 No.3

목적 : Cerivastatin(LIPOBAY)은 최근에 개발되어 사용되기 시작한 HMG-CoA 환원효소 억제제로서 저용량으로 탁월한 콜레스테롤 강하효과를 보이는 약물이다. 저자들은 Cerivatatin(LIPOBAY)의 혈중 콜레스테롤 강하효과를 평가하고 약물의 안전성을 평가하기 위하여 본 연구를 시행하였다. 방법 : 고콜레스테롤혈증 환자 37명(남자 13명, 여자 24명)을 대상으로 하였다. 대상환자는 2주간의 저콜레스테롤 식이 후에도 혈청 콜레스테롤이 240㎎/㎗이상이거나, 관상동맥질환이 있는 환자는 혈청콜레스테롤이 220㎎/㎗이상인 경우 cerivastatin 0.4㎎을 8주간 복용하도록 하였다. 임상적 관찰과 검사실 검사(간기능검사, 일반혈액검사, 혈청지질검사)는 투약개시 후 4주 및 8주 후에 시행하였다. 결과 : Cerivastatin 0.4㎎을 4주간 투여한 후 측정한 LDL 콜레스테롤, 총콜레스테롤, triglyceride, 및 HDL 콜레스테롤은 각각 38%, 28.8%, 11.6% 및 7.8% 감소하였다. 총콜레스테롤/HDL 콜레스테롤 비 및 LDL/HDL비는 각각 20.8% 및 31.1% 감소하였다. 투약 8주후에 측정한 검사소견은 4주후에 비해 유의한 변화를 보이지 않았다. 한명의 환자(2.7%)에서 간기능 검사상 AST, 및 ALT의 지속적인 상승으로 투약을 중지하였다. 결론 : Cerivastatin 0.4㎎/day는 혈청콜레스테롤을 효과적으로 감소시켰으며 심각한 부작용은 볼 수 없었다. 따라서 적극적으로 LDL콜레스테롤을 낮출 필요가 있는 고콜레스테롤혈증 환자에서 cerivastatin은 효과적이고 안전한 약물이라고 생각된다. Objectives : Cerivastain(LIPOBAY) is recently developed HMG-CoA reductase inhibitor which is effective in lowering serum cholesterol levels at microgram does. We evaluated the clinical efficacy and safety of cerivastatin(LIPOBAY) in patients with hypercholesterolemia. Method : Thirty-seven patients(male : 13, female : 24) with hypercholesteolemia defined as baseline serum total cholesterol ≥240㎎/㎗, or ≥220㎎/㎗ in patients with known coronary artery disease were included for this study. After 2 weeks of low cholesterol diet, if the serum total choesterol level meet the criteria, cerivastain 0.4㎎/day was prescribed for 8 weeks. Clinical follow-up and laboratory tests were performed 4 weeks and 8 weeks after medication. Results : After 4 weeks of cerivastain 0.4㎎/day treatment, low density lipoprotein(LDL) cholesterol decreased 38% and total cholesterol decreased 28.8% from baseline. Triglyceride decreased 11.6%, and high density lipoprotein(HDL) cholesterol decreased 7.8% from baseline. Total cholesterol/HDL ratio decreased 20.8% and LDL/HDL ratio decreased 31.1% from baseline. After 8 weeks of treatment, no further significant changes were noted compared with the values at 4 weeks. Cervastatin was discontinued in one patient(2.7%) due to continuous liver enzyme elevation. Conclusion : Cerivastatin 0.4㎎/day is effective in lowering serum cholesterol levels without significant adverse reactions. Cerivastatin is effective and safe for patients with hypercholesterolemia who needs aggressive LDL cholesterol lowering.

초소형 구조물의 부착 방지를 위한 새로운 자기 집합 물질에 대한 연구

김봉환,오창훈,전국진,정택동,변장웅,이윤식 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

In order to achieve stiction-free polysilicon surfaces, we have suggested a new chemical grafting precursor and confirmed their excellent characteristics. When dichlorodimethylsilane(DDS, C_(2)H_(6)SiCl_(2)), a dialkyldichlorosilane widely used in silicon machining, have been used as a precursor, experimental results were clearly comparable to those of monoalkyltrichlorosilanes octadecyltrichlorosilane (OTS, C_(18)H_(37)SiCl_(3)) or 1H,1H,2H,2H-perfluorodecyltrichloro-silane (FDTS, C_(10)H_(4)F_(17)SiCl_(3)) in terms of stiction reduction. The polysilicon cantilevers were fabricated in the carefully controlled conditions and laser interferometer indicated that their residual stress gradient was 2 MPa/μm upward from the substrate. The SEM images of polysilicon cantilever beams with DDS coating are upward and no stiction is observed up to 2 mm in length.

Bacterial Species and Antibiotic Sensitivity in Korean Patients Diagnosed with Acute Otitis Media and Otitis Media with Effusion

Kim, Sang Hoon,Jeon, Eun-Ju,Hong, Seok Min,Bae, Chang Hoon,Lee, Ho Yun,Park, Moo Kyun,Byun, Jae Yong,Kim, Myung Gu,Yeo, Seung Geun The Korean Academy of Medical Sciences 2017 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.32 No.4

<P>Changes over time in pathogens and their antibiotic sensitivity resulting from the recent overuse and misuse of antibiotics in otitis media (OM) have complicated treatment. This study evaluated changes over 5 years in principal pathogens and their antibiotic sensitivity in patients in Korea diagnosed with acute OM (AOM) and OM with effusion (OME). The study population consisted of 683 patients who visited the outpatient department of otorhinolaryngology in 7 tertiary hospitals in Korea between January 2010 and May 2015 and were diagnosed with acute AOM or OME. Aural discharge or middle ear fluid were collected from patients in the operating room or outpatient department and subjected to tests of bacterial identification and antibiotic sensitivity. The overall bacteria detection rate of AOM was 62.3% and OME was 40.9%. The most frequently isolated Gram-positive bacterial species was coagulase negative <I>Staphylococcus aureus</I> (CNS) followed by methicillin-susceptible <I>S. aureus</I> (MSSA), methicillin-resistant <I>S. aureus</I> (MRSA), and <I>Streptococcus pneumonia</I> (SP), whereas the most frequently isolated Gram-negative bacterium was <I>Pseudomonas aeruginosa</I> (PA). Regardless of OM subtype, ≥ 80% of CNS and MRSA strains were resistant to penicillin (PC) and tetracycline (TC); isolated MRSA strains showed low sensitivity to other antibiotics, with 100% resistant to PC, TC, cefoxitin (CFT), and erythromycin (EM); and isolated PA showed low sensitivity to quinolone antibiotics, including ciprofloxacin (CIP) and levofloxacin (LFX), and to aminoglycosides. Bacterial species and antibiotic sensitivity did not change significantly over 5 years. The rate of detection of MRSA was higher in OME than in previous studies. As bacterial predominance and antibiotic sensitivity could change over time, continuous and periodic surveillance is necessary in guiding appropriate antibacterial therapy.</P>

복숭아 과실의 발육 중 펙틴질 및 polygalacturonase 활성의 변화

장경호(Kyung Ho Chang),김대현(Dae Hyun Kim),김임수(Im Soo Kim),이동훈(Dong Hoon Lee),변재균(Jae Kyun Byun) 한국원예학회 2000 원예과학기술지 Vol.18 No.5

CO₂ SORPTION MECHANISM OF A K-Mg-BASED SORBENT AT HIGH PRESSURE FOR SEWGS CO₂ CAPTURE

Chang Ki Byun,Hyo Bin Im,Jeong Min Jeong,Ji Hye Park,Jeong Hoon Baek,Ho Jung Ryu,Kwang Bok Yi 한국신재생에너지학회 2015 AFORE Vol.2015 No.11

Liquid Formulation of Lactoferrin as a Model Glycoprotein

Chang Hoon Shin,Tae Ho Byun,Chan-Wha Kim 한국생물공학회 2005 한국생물공학회 학술대회 Vol.2005 No.4