Ti-6Al-4Fe-0.5Si 합금에서 Ti-Si 석출과 베타상의 방위관계

최병학,김진우,정희원,현용택,김승언,이용태 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.1

This study examined the effect of Si addition in (α+β) Ti alloy on the phase stability about the Ti silicide precipitation from b matrix. The changes in the volume fraction and shape of precipitates with different Si contents were correlated with the tensile properties of the present alloys based on the detailed TEM micrographic observation. In Ti-6Al-4Fe-0.5Si alloy, the precipitates with rectangular or round shape were found at inter-grain of α/β interface and intra-grain of β phase. The precipitates were generally known as Ti5Si₃ with enough stabilizing thermo-mechanically. However, in this study, a new type silicide of Ti_(5)Si₄was mostly observed in the as-cast specimens, representing the metastable or unstable state phase thermo-mechanically compared to Ti_(5)Si₃. It was consistent with the phase transformation processes of TiSi₂TiSiTi_(5)Si₄Ti5Si₃ in the ternary alloy system of Ti-Al-Si. The improvement of mechanical properties including high temperature ones was to be induced by the fine precipitation of Ti silicides such as Ti5Si₄ and Ti5Si₃ in the ductile matrix of b phase. The precipitates of Ti_(5)Si₄ (P1) and Ti_(5)Si₃ (P2) have a coherent relationship with bcc β matrix of (200)_(β) //(220)_(P1) //(2111)_(P2) and (011)_(β) //(001)_(P1)//(0110)_(P2).

DCJTB를 도핑시킨 단층 Alq₃소자에서 Two-color filter를 사용한 발광영역의 결정

채우리,채희백,최성진 순천향대학교 기초과학연구소 2011 순천향자연과학연구 논문집 Vol.17 No.2

A doping layer of thickness 2 nm of DCJTB(guest) was dopoed 1 % and varied its location 5nm each from the anode to the cathode in a single layer Alq(60 nm, host) OLED in order to investigate the region of charge recombination and light emission. Major emission peak was located 20 nm from the anode and the emission region was shown to be spread through the whole layer of Alq. We also investigate a method to determine the recombination zone with two-color filter from TEL

건강검진에서 발견된 폐결절에 대한 임상경과

최강현,박진우,한윤수 충북대학교 의과대학 충북대학교 의학연구소 2010 忠北醫大學術誌 Vol.20 No.1

연구목적 : 최근 건강검진에서 흉부 전상화단층촬영을 흔히 시행하면서 비석회화 폐결절의 발견이 증가하고 있다. 그러나 이들 폐결절이 여러 번의 추적검사에서 악성으로 밝혀지는 경우는 많지 않다. 따라서 이러한 폐결절에 대해 추적검사를 반드시 필요한 경우를 알아보고자 하였다. 대상 및 방법 : 2007년부터 건강검진을 받은 후 흉부 전산화단층촬영에서 비석회화 폐결절이 발견된 환자를 대상으로 폐결절의 위치, 크기 및 성상을 조사하였다. 추적 전산화단층촬영은 3,6,9,12 및 24개월 후로 계획하였고 폐결정의 변화를 알아보았다. 결과 : 대상환자는 모두 122명으로 남자 107명(87.7%), 여자 15명(12.3%), 이들의 평균연령은 53±10세이었고, 흡연자는 71명(85.2%)이었다. 폐결절이 1개인 경우는 62명(50.8%)으로 가장 많았고, 2개인 경우가 29명(23.8%), 3개인 경우가 12명(9.8%), 4개 이상인 경우가 19명(15.6%)이었다. 결절의 내무가 견고(solid)하며 경계가 분명(distinct)한 경우가 89례, 내부가 견고하지만 경계가 불분명(fuzzy)한 경우가 10례, 내부가 간유리형(ground-glass)이며 경계가 분명한 경우는 7례, 내부가 간유리형이며 경계가 불분명한 경우가 16례로, 내부가 견고하면서 경계가 분명한 경우가 가장 많았다. 흉부 전산화단층촬영상 비특이적이거나 양성으로 여겨지는 경우는 108(88.5%)이었고, 14명(11.54%)에서는 악성 또는 양성으로 구분할 수 없는 상태였다. 추적관찰은 116명(95.1%)에서 한번 이상의 추적 흉부 전산화단층촬영이 시행되었다. 추적관찰은 116명(95.1%)에서 한번 이상의 추적 흉부 전산화단층촬영이 시행되었다. 추적관찰의 기간은 평균 10.8±7.3개월이었다. 추적관찰 중에 5명(4.1%)에서는 결절이 완전히 소실되었고, 8명(6.6%)에서는 일부 호전되었고, 95명(77.9%)에서는 결절의 변화가 없었다. 2명(1.6%)에서는 한 개의 결절이 있었는데, 그 크기가 증가하였다. 3명(2.5%)에서는 결절수가 증가하였다가 다시 감소하였고, 또 다른 3명(2.5%)에서는 결절 수가 감소하였다가 다시 증가하였다. 크기가 증가한 결정 환자 3명 중 1명은 선암으로 판명되었고, 다른 한명은 폐결핵으로 진단되었다. 1년 이상 추적관찰을 한 48명의 환자 중, 처음 추정진단이 '비특이적 결절' 이거나 '양성 결절'인 경우에는 악성으로 진단된 환자는 없었다. 결론 : 건강검진시 발견된 폐결절 환자 중, 처음 추정진단이 '비특이적 결절' 또는 '양성 결절' 일 경우에는 반드시 추적검사가 필요하지 않을 수 있으나 더 대규모의 장기간 연구가 필요하다. Purpose : The number of patients with pulmonary nodules detected by computed tomography in general health evaluation has recently been increased. A very little portion of these patients, however, turned to have malignant nodule, and the rest of the patients had to be checked follow-up computed tomography repeatedly. This study was performed to evaluate any condition that avoid repeated tomography in these patients. Materials and Methods : Patients with noncalcified pulmonary nodules detected in general health evaluation were enrolled. Their symptoms, smoking history, location, size and nature of the pulmonary nodules were evaluated. Follow-up chest computed tomoraphy was checked after 3, 6, 9, 12 and 24 months later. Results : One hundred twenty-two patients (male:female, 107:15) were enrolled and their mean age was 53 ± 10 years. Seventy-one (85.2%) patients were smoker. Sixty-two (50.8%) patients had one nodule, 29 (23.8%) patients had 2 nodules, 12 (9.8%) patients had 3 nodules, and 19 (15.6%) patients had 4 or more nodules. The mean size of the biggest nodule in each patients is 5.7 ± 3.0mm. Solid nodules with distinct margin were most frequent. There was a tendency that solid nodules had distinct margin, whereas ground-glass nodules had fuzzy margin (p < 0.001). One hundred sixteen (95.1%) patients were followed-up at least once. In two patients, their nodules increased in size within 3 and 6 months. One was adenocarcinoma and the other was pulmonary tuberculosis. Among the patients who was followed-up over one year, no patients had malignant nodules. The patients with initial presumptive diagnosis as 'nonspecific' or 'benign' nodule, had no malignancy after one year. Conclusion : In 1.6% of patients, the pulmonary nodule increased in size within 6 months, one was adenocarcinoma, and the other was tuberculosis. In the patients with initial presumptive diagnosis as 'nonspecific' or 'benign' nodule on computed tomography, no nodule turned to be malignant. A longer and larger-scale study is needed.

이상형 스테인레스강의 크롬질화물 석출과 상 방위관계 연구

최병학,김진우,고석민,조용석,김상식,이재현 국립7개대학공동논문집간행위원회 2002 공업기술연구 Vol.2 No.-

Microstructures in the directionally solidified duplex stainless steels were investigated in order to understand the effect of nitrogen addition and its precipitation in the α phase. It was found that the addition of nitrogen causes the formation of fine precipitates in α matrix and segregation phases of nitrogen in the α/γ interface. Both the fine precipitates and the segregation phases were identified as CrN(fcc, a=4.18Å), as a coherent phase related to the α-bcc matrix with crystal relationship of (200) CrN//(01￣1)α and (1￣1￣1)CrN//(3￣2￣1)α.

방향성 응고된 이상형 스테인레스강에서 질소첨가가 미세조직에 미치는 영향

최병학,정병길,김진우,고석민,이재현,김상식,김성준 국립7개대학공동논문집간행위원회 2001 공업기술연구 Vol.1 No.-

Microstructures in the directionally solidified duplex stainless steels were investigated in order to understand the effect of nitrogen addition. It was found that the addition of nitrogen causes formation of fine precipitates in a matrix and segregation phases of nitrogen in the α/γ interface. Both the fine precipitates and the segregation phases were identified CrN(fcc, a=4.16A˚), which has the coherent phase relationship with bcc α matrix of (200) CrN // (0 1￣ 1) α and (1￣1￣ 1) CrN // ( 3￣ 2￣ 1) α.

Vancomycin-Resistant Enterococci (VRE) 빈도, 검사법 및 감염관리 대책에 관한 전국 병원 설문조사

정희진,김우주,최선주,이경원,최강원,박승철 대한감염학회 2001 감염 Vol.33 No.2

Background : Vancomcyin-resistant enterococci (VRE) have been an important nosocomial pathogen in the 1990s. Recently, VRE have become an emerging nosocomial pathogen in Korea, but there have been no nationwide study about the status of VRE in Korea. This nationwide questionnaire survey was aimed to determine the prevalence of VRE, the appropriateness of detection method fur VRE, and to evaluate the infection control program in hospitals of various size in Korea. Methods : During 4 weeks (September 1 to October 1, 1999), a questionnaire surveillance study was conducted. We had sent the questionnaire to 200 large hospitals in Korea, which were distributed nationwide. Questionnaire included the prevalence of VRE within the hospital, the detection method for VRE, method of enterococci isolation, antibiotics-susceptibility test and infection control method of VRE. Results : The response rate to questionnaire was 42%. The species identification of enterococci was capable in 62.3% but the accurate enterococcal speciation were capable in 18%. Appropriate antibiotic-sus-ceptibility test were produced only in 6.5%. Total 746 VRE were detected in 42 hospitals during 1-year despite of low sensitivity of detection methods. VRE was noted in 54.4% of hospitals at least. The isolation programme of VRE infected patients was presented in 20.3%, regular surveillance of VRE in high-risk pop ulation was produced only in 16.5%. Conclusion : The prevalence of enterococci among microorganisms isolated from clinical specimens were increased up to 27.7% in Korea. VRE has been emerged in many big cities as well as in Seoul. The microbiological methods that include the speciation of enterococcal isolates, antimicrobial susceptibility test, and VRE detection appeared to be inappropriate in many hospitals. And, proper control and prevention methods were presented in a few hospitals. Education and training about accurate detection of VRE as well as proper infection control programs for VRE are urgently needed. (Korean J Infect Dis 33:78~87, 2001)

전국 10개 종합병원 중환자실 환자의 직장내 Vancomycin-resistant Enterococci(VRE) 보균율, 보균의 위험요인 및 유전적 다양성 조사

정희진,송준영,엄중식,김우주,최선주,최정현,이혁,정문현,이광미,신동현,손보라,최종성,우흥정,권정아,이경원,최강원,박승철 대한감염학회 2002 감염 Vol.34 No.5

血淸 Lithium 濃度와 腦脊髓液 Lithium 濃度와의 相關關係

金載軫,李相益,金辰圭,崔范,禹鍾仁 서울醫大 1990 精神醫學 Vol.15 No.2

삼첨판 기계식 인공판막 대치술을 포함한 세 차례 개심술을 시행한 환자에서 대심정맥을 통한 영구 박동조율기 이식 1예 보고

김재욱,이진호,최주원,김우식,김용인 인제대학교 백병원 2003 仁濟醫學 Vol.24 No.2

A 26-year-old man. who had undergone three times open heart surgeries including tricuspid mechanical valve replacement 4 months before, with general weakness and mild dyspnea was admitted. He presented a third degree atrioventricular block on the electrocardiogram and required permanent pacemaker implant. We successfully implanted a permanent pacemaker transvenously with a ventricular lead introduced into the great cardiac vein via coronary sinus to stimulate the left ventricle, an atrial lead in the right atrium, and his symptoms improved.

Gene Expression Patterns and Developmental Competence of Pre-Implantation Embryos in Cattle

Woo-Jin Son,S. Balasubramanian,Mohana kumar B,Sun-A Ock,Sang-Yong Choe,Gyu-Jin Rho 한국동물번식학회 2006 Reproductive & Developmental Biology(Supplement) Vol.30 No.2s