Buffer/CoFe/Cu/Co 샌드위치 박막의 자기저항 특성

김희중,김미양,오미영,이장로,송은영,김경민 숙명여자대학교 자연과학연구소 1996 자연과학논문집 Vol.- No.7

DC magnetron sputtering방법으로 Corning glass 기판위에 버퍼층을 Fe와 ??로 바꾸어가면서 보자력이 다른 ??와 Co를 이용하여 buffer/CoFe(35Å)/Cu(tÅ)/Cu(35Å)의 형태로 샌드위치 박막을 제작하고 자기저항비의 버퍼층 두께 및 비자성층 Cu층 두께, 자성층 두께 의존성을 조사하였다. 자기저항비와 포화 자기장(??)은 버퍼층의 두께가 두꺼워짐에 따라 증대하다가 극대치 3%를 보인 후 완만하게 감소하였다. NiFe, Fe버퍼층을 갖는 시료를 비교한 경우, 각각 CoFe층과 Co층 사이의 결합 자기장(??)은 큰 차이가 없었으나 NiFe버퍼층을 갖는 시료가 minor자기저항 곡선의 반가폭 ??는 감소하고 자기저항(MR) slope와 관련된 field senditivity(%/Oe)는 향상되었다. Buffer(tÅ)/CoFe(35Å)/Cu(50Å)/Co(35Å) sandwiches prepared by dc magnetron sputtering on a corning glass substrate using ?? and Co possess different coercivities. Dependence of magnetoresistance on the type and thickness of buffer layer, thickness of Cu and thickness of magnetic layer in buffer/CoFe/Cu/Co sandwiches were investigated. Magnetoresistance ratio and saturation field ?? increased as the thickness of buffer layer becomes thicker, then decreased smoothly after maximum value. Improved field sensitivity was realized by the use of ?? buffer layer.

심인성 색전 요인이 없는 뇌경색 환자에서 경식도 심초음파와 Acoustic Quantification을 이용한 대동맥 탄성의 평가

이종민,윤호중,임효영,박지원,김휘열,전희경,문건웅,정욱성,채장성,김재형,최규보,홍순조 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.8

生産工程의 最適工程平均의 決定

李敏九,張重淳,金明洙 西原大學校 經營科學硏究所 1997 經營硏究 Vol.6 No.1

H9c2 심근 세포주에서 외인성 nitric oxide가 허혈에 의한 세포 독성에 미치는 영향

정성구,장현용,김명천,고영관,정주호,배영미,박원서,김대중,유영민,김성수,임성빈 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Nitric oxide(NO) is known to have protective effects on an ischemic heart and to exert triggering effects on ischemic preconditioning. However, the effects of NO during the ischemic period have not been investigated. To investigate the role of exogenous nitric oxide in a model of ischemic heart cell death, we studied the effects of ischemic preconditioning and ischemia in a normal and an ischemic buffer. Methods: Rat cardiac myoblast cells(H9c2) were cultured in a normal and an ischemic buffered medium. For the ischemic culture of heart cells, the cells were cultured in a dessicator with GasPak for 5 hrs. In ischemic preconditioning, the cells were pretreated with ischemic buffer for 5 min and then perfused with normal medium for 30 min. For the measurement of the cytotoxicity, a MTT(3-4-Sdimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide) assay was performed. A DAPI(4',6-diamidino-2-phenylindole dihydrochloride) staining procedure and a flow cytometry analysis were performed to confirm apoptotic cell death by ischemia. Results: Cell viability, as determined by using a MTT assay, showed that the preconditioned group treated with NO showed more cell death than with the not-preconditioned groups in both normal and ischemic buffers. But, In normal medium and not-preconditioned groups, NO showed protective effect according to the concentrations(100,1000μM) . No treatment with NO produced the different results. In normal medium, the protective effect of ischemic preconditioning was demonstrated, but no protective effect of ischemic preconditioning could be seen in the case of the ischemic buffer. The DAPI staining and flow cytometry analysis of heart cells showed characteristic apoptotic features. Conclusion: NO added in the ischemic phase had deterious effects on heart cells. Ischemic preconditioning was more harmful than ischemia alone. The toxicity of the cells was characteristic apoptosis.

고유함수전개법을 이용한 비대칭 유전체 원주공진기의 공진특성해석

류원열,민경호,장중호,전오곤,이창화,최현철 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

The resonant frequency of the dielectric rod resonator which is surrounded by cylindrical cavity can be calculated very exactly by using eigenfunction expansion method in the concept of electric and magnetic wall from the symmetry. But if the supporter is put in the cavity, the symmetry disappears. Thus this method has some errors. In this paper, the resonant frequency of the asymmetric dielectric rod resonator was calculated by using the eigenfunction expansion method. Also, the effect of the supporter was discussed. Then we found that the resonant frequency was more affected in the case of TM mode than TE or Hybrid modes as the length of the supporter was longer.

관상동맥 풍선성형술 후 발생한 관상동맥 박리의 초기 조영술적 고찰

고영엽,강지인,장재혁,강민정,정중화,장경식,홍순표 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.1

Background and Objectives: Percutaneous coronary intervention (PCI) is widely utilized in the treatment of symptomatic coronary artery disease (CAD). Althouth it has numerous benefits, intimal tear or dissection, serious and potentially life-threatening complications of plain old balloon angioplasty (POBA) can occur. The aim of this study was to assess the implications of coronary dissections after ballon angioplasty. Methods: 78 consecutive patients (age, 62 +/- 11 years; 46 men, 32 women) identified to two groups as having with or without dissection (dissection (D) group or non-dissection (ND) grouP) underwent balloon angioplsty for CAD were studied. All patients with dissection could be managed by successful stent implantation to rescue the artery. The morbidity of ischemic complication and mortality were evaluated for 30days after PCI. Results: Coronary dissection developed 44 lesions (38%) in 31 patients out of 117 lesions in 78 patients after POBA and a good final angiographic result was obtained in all patients with dissection, Significant correlates of a development of dissection were the lesion morphology of ACC/AHA type B and C (P<0.05). There were no significant correlations of clinical pictures, whether POBA in single vessel disease or in multivessel disease, diameter stenosis before POBA, and balloon/coronary artery diameter ratio. Morphologic feature of dissection was type A in 15 (34%), type B in 13(30%), type C in 12 (27%), and type D in 4 (9%). After PCI, there was no ischemic complication or death related coronary dissection during follow-up period for 30days. Conclusions: Coronary dissection after angioplasty occurred in 44 lesions (38%) out of 117 lesions of 78 consecutive patients underwent POBA. Coronary dissection after POBA significantly correlated with the severity of lesion morphology. Coronary stenting is effective in the management of acute coronary dissections after angioplasty.

버퍼층 및 열처리 효과가 CoFe/Cu 다층박막의 자기저항에 미치는 영향

오미영,송은영,이장로,김희중,김경민,김미양 숙명여자대학교 자연과학연구소 1996 자연과학논문집 Vol.- No.7

DC magnetron sputtering방법에 의해 Corning glass기판 위에 ?? 형태로 다층박막을 제작하여 버퍼층 종류(Fe, Cu, Cr, Ta)와 두께, 비자성층인 Cu두께 변화에 관한 자기저항비의존성을 조사하였다. 또한 이들 시료에 대하여 열처리를 행한 후 열처리가 이 시료의 구조, 자기적 성질 및 자기저항에 미치는 영향을 조사하였다. Fe버퍼층의 두께가 60Å일 때 극대 자기저항비가 14%인 자기저항이 관찰되었고 Fe버퍼층과 Cr버퍼층을 갖는 시료를 비교한 경우 자기저항비는 그다지 차이가 없으나 Fe버퍼층이 있는 경우에 더 큰 포화자기장 및 자기 이력현상을 나타내었다. 250℃까지의 시료에 대한 열처리는 다층박막의 주기성을 유지한채 더 큰 결정립을 갖게 하여 자기저항비는 증가하였으나 그 이상의 온도에서는 계면 혼합 및 계면 확산에 의한 감소를 나타내었다. Giant magnetoresistance (GMR) and magnetic properties of CoFe/Cu multilayers prepared by dcmagnetron sputtering has been studied. We investigated the effect of Fe buffer layer thickness, different buffer layers, and annealing condition on GMR. For the 60Å Fe buffer layer thickness, maximum MR ratio 14% was found. When we have used different buffer layers, multilayers with Cr and Fe buffer show similar GMR magnitude, but multilayers with an Fe buffer have much higher saturation fields and hysteresis. The study of the dependence of the MR behaviors on annealing temperature, the MR ratio was increased to 250℃, but reduced at the temperature higher than 300℃ because of the interfacial diffuse.

다제내성 그람양성균에 대한 Linezolid(Zyvox^(�))의 시험관내 항균력 비교

박대원,정희진,엄중식,황병연,김성범,이재갑,이연주,정혜원,정성주,박재형,이진수,손장욱,김우주,김민자,박승철 대한감염학회 2003 감염과 화학요법 Vol.35 No.5

배경 : MRSA, VRE, VRSA같은 다제 내성 그람 양성균의 등장에 따라 glycopeptide를 대체할 새로운 항생제의 개발이 필요하게 되었고 결과적으로 새로운 항생제인 linezolid라는 항생제가 개발되었다. Linezolid는 이전의 항생제와는 다른 새로운 계열의 oxazolidinone으로 경구 이용률이 우수하다. 원내 및 원외감염의 중요한 원인균이 되고 있는 MRSA, VRE에 대한 적절한 경구용 항균제가 없는 국내에서 폐렴 및 피부 연조직 감염에서 경구용으로 사용해 볼 수 있는 약제이다. 본 연구에서는 고대 구로 병원에서 분리된 MRSA, VRE 등을 대상으로 다른 여러 항균제와 비교한 linezolid의 시험관내 항균력을 조사하고자 하였다. 재료 및 방법 : 연구대상은 1998년 1월부터 2000년 12월까지 본원에서 입원 및 외래를 통하여 피부 연조직 감염증 및 호흡기 감염증, 요로감염증으로 진단된 환자들의 가검물로부터 분리된 MRSA 60균주, VRE 43균주, PRSP 25균주를 액체배지 또는 한천배지 희석법을 통하여 linezolid 및 기타 항균제에 대한 최소발육억제농도를 구하였다. 결과 : 실험에 사용한 S. aureus는 모두 MRSA였고 이들은 linezolid에 대해 MIC_(90) 2㎍/㎖(MIC 범위 1-2㎍/㎖), Enterococcus spp는 모두 VRE로 linezolid의 MIC_(90)은 2㎍/㎖로 MIC 범위는 1-4㎍/㎖였다. 한 개의 균주에서 MIC 4㎍/㎖로 중등도 감수성을 보였으나 MIC breakpoint가 (8㎍/㎖인 내성균주는 없고 모두 감수성을 보였다. S. pneumoniae의 경우 penicillin 내성이었고, linezolid MIC_(90) 1㎍/㎖ (MIC 범위 0.5-1㎍/㎖)로 전부 감수성을 보였다. 결론 : Linezolid는 MRSA를 위시한 VRE, PRSP 등의 다제 내성 그람 양성균에 대하여 우수한 시험관내 항균력을 보임을 알 수 있었다. Background : The emergence of multi-drug resistant Gram-positive cocci, such as MRSA, VRE, and VRSA, necessitated to develop new antibiotics, which could replace the glycopeptide. As a result, a new antibiotics named linezolid was developed. Linezolid is different line of oxazolidinones with a good oral bioavailability, compared to other antibiotics. Since appropriate oral antibiotics are not presently available for MRSA, which is a major cause of nosocomial and community acquired infections, the introduction of linezolid will have favorable effect on treatment of infections such as pneumonia or skin infections. In this study, we investigated the antibiotic effect of linezolid on MRSA and VRE isolated from patients who were treated in Korea University Guro Hospital. Material and Methods : By using broth microdilution and agar dilution method we measured minimum inhibitory concentration (MIC) with sixty S. aureus, forty three Enterococcus spp., and twenty five S. pneumoniae isolates from patients who were diagnosed as skin, soft tissue, respiratory, and urinary infections in Korea University Guro Hospital from January, 1998 to December, 2002. Results : All of S. aureus used in this study were MRSA, and MIG_(90) of linezolid was below 2 ㎍/㎖ (MIC ranged between 1-2 ㎍/㎖). All of Enterococcus spp. were VRE, and had MIG_(90) of 2 ㎍/㎖ (MIC ranged between 1 to 4 ㎍/㎖). One of the VRE showed intermediate susceptibility with MIC of 4 ㎍/㎖. However, none was resistant with MIC breakpoint above 8 ㎍/㎖. All of S. pneumoniae were resistant to penicillin, but they were susceptible to linezolid with MICao of 1 ㎍/㎖(MIC range 0.5-1㎍/㎖). Conclusion : In conclusions, linezolid has an excellent in vitro antibiotic effect on multi-drug resistant Gram-positive cocci, such as MRSA, PRSP, and VRE.

냉장고 압축기의 소음불량 원인 분류를 위한 딥 러닝 활용 방안

이동현(Dong-Hyeon Lee),장준영(Jun-Young Jang),정의봉(Weui-Bong Jeong),홍진숙(Chinsuk Hong) 한국소음진동공학회 2019 한국소음진동공학회 학술대회논문집 Vol.2019 No.10

서울 강서지역 1개 대학병원에서 성인 급성 신우신염의 원인균과 항생제 감수성

황병연,이재갑,박대원,이연주,김성범,엄중식,손장욱,정희진,김우주,김민자,박승철 대한감염학회 2003 감염과 화학요법 Vol.35 No.5

목적 : 3년간 서울시 강서지역의 1개 대학병원에서 입원치료를 받은 성인 급성 신우신염 환자를 대상으로 원인균과 항생제 감수성을 조사하고, 향후 급성 신우신염의 초기 경험적 치료 항생제를 제안하고자 하였다. 방법 : 1999년 1월부터 2001년 12월까지 3년간 고려대학교 의과대학 구로병원에 상부요로감염으로 내원한 16세 이상 환자 229명의 의무 기록을 검토를 통하여, 인구학적 특성, 원인균, 항생제 감수성, 초기 항생제 사용 양상과 입원기간을 조사하였다. 결과 : 연구에 포함된 229명을 118명의 단순 신우신염군과 111명의 복잡 신우신염군으로 구분 하였다. 단수 신우신염의 평균 발생 연령은 38.2세와 복잡 신우신염 56.1세로 복잡 신우신염 환자의 연령이 유의하게 높았다(P<0.001). 양군 모두에서 원인균 중 E. coli의 분리율이 가장 높았으며 항생제 감수성 결과 ampicillin, trimethoprim-sulfame-thoxazole에는 높은 내성률을 보였고, ciprofloxacin, gentamicin, cefotaxime에 대한 감수성은 비교적 높았으나 복잡 신우신염의 경우 단순 신우신염에 비하여 ciprofloxacin, gentamicin에 대한 감수성이 다소 낮은 것을 확인할 수 있었다. 평균 입원 기간, 항생제 투여 기간에 있어서도 복잡 신우신염군에서 유의하게 길었다. 결과 : 본 연구의 결과 서울의 강서 지역에서 대학병원급에 치료 의뢰되는 단순 급성 신우신염의 치료에 있어 1차 항생제로 3세대 cephalosporin, aminoglycoside, quinolone 중 한가지를 초기 경험적 치료제로 사용을 고려하여야 할 것으로 사료된다. Background : The purpose of this study is to recommend the initial therapeutic regimen for adult patients with acute pyelonephritis (APN) according to the changes of antimicrobial susceptibility patterns of causative microorganisms isolated from patients with APN. Methods : We reviewed medical charts of 229 APN patients, who had been treated at Korea University Guro Hospital from 1st of January. 1999 to 31st of December, 2001. We investigated the demographic data, clinical findings, durations of hospital treatment, antimicrobial susceptibility patterns of the causative microorganisms and initial antibiotic regimens in patients with APN. Results : In this study, 229 adult patients with APN were classified into simple APN patients (118 patients, 51.5%) and complicated APN patients (111 patients, 48.4%). Mean age of patients with simple APN was 38.2±14.1 years old and that of patients with complicated APN was 56.1±14.9 years old. Mean age of patients with complicated APN was significantly higher than that of simple APN patients (P<0.0001). Escherichia coli was the most common microorganism both in simple APN (96.7%) group and in complicated APN (90.6%) group. Antimicrobial susceptibility of E. coli was at the low level of ampicillin (31%/20%) and trimethoprim-sulfamethoxazole (42.6%/34.2%) in each group. In contrast, ciprofloxacin (11.5%/22.7%), gentamicin (16.4%/22%) and cefotaxime (0%/8.2%) resistance remained at relatively lower level. In comparison of simple APN with complicated APN, ciprofloxacin and gentamicin resistances were higher in complicted APN group. Average duration of hospitalization (5.9±2.3 days/8.2±4.6 days) and duration of antibiotic use (12.1±3.9 days/15.3±10.0 days) were significantly longer in complicated APN. Conclusions: The results of this study suggests that 3rd cephalosporin, aminoglycoside or quinolone antibiotic would considered as one of the initial therapeutic regimen for patients with simple APN in southwestern Seoul.