급성 심근경색증 초기 진단에 latex 응집을 이용한 혈청 myoglobin 측정의 임상적 의의

박영배,서정돈,최윤식,이영우,오병희,손대원,임하진,김유우,박명희 대한내과학회 1987 대한내과학회지 Vol.32 No.2

We evaluated the diagnostic usefulness of latexagglutination test for elevated serum myoglobin as a screening test in the early phase of acute myocardial infarction and 21 patients with chest pain mimicking acute myocardial infarction were included in this study. Result was compared with serum myoglobin level measured by radioimmunoassay (RIA) in every case. The Following results were obtained: 1) When serum myoglobin levels measured by RIA below 85ng/㎖ were regarded as normal, this test showed sensitivity of 82%, specificity of 95%. 2) In latex-agglutionation test for elevated serum myoglobin, test results were interpreted as negative, weakly positive and positive. If we regard weakly positive tests as positive, sensitivity was 93% and specificity was 62%. In contrast, if we regard weakly positive tests as negative specificity rose to 100% while sensitivity reduced to 75%. 3) Agreement rate of both test was k=0.59. It is suggested that latex-agglutination test for elevated serum myoglobin is helpful in ruling out acute myocardial infarction when test result is negative, and that it can be used as a screening test in the early phase of acute myocardial infarction because of its rapidity and simplicity in performing the procedure.

인공판막 재대치험예에서의 판막실패의 양상

박영배,김유호,서정돈,최윤식,이영우,오병희,도문홍,최동주,전은석 대한내과학회 1987 대한내과학회지 Vol.32 No.3

In order to observe the aspects of prosthetic cardiac valve failure, we analyzed 26 cases of Redo operation among 1081 cases of valve replacemant performed from Jan. 1961. to July 1986. The results are as follows; 1) Crude Redo operation rate was 2.4%. 2) The most common cause or prosthetic cardiac valve failure was the primary tissue failure (73%) 8r the PVE was the 2nd (15.4%). 3) Mean valve implantation time was 47.7 months. Implantation time in the child group was shorter than in adult by 6.8 months, In the primary tissue failure group (19 cases) implantation time in the child was 42.8 months 8z in adult, 66.8 months. (P$lt;0.05) In conclusion, the durability of tissue valves was significantly decreased in the child age group because of increased propensity for calcification, so the preference of tissue valves especially in this age group should be reconsidered.

Zone melting furnace 온도와 성장속도가 90 % Bi2Se3n 형 단결정의 열전특성에 미치는 영향

현도빈,황종승,심재동,오태성,하헌필 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.1

The effects of the zone melting temperature and growth rate on the thermoelectric properties for 0.15 wt% CdI₂ and 0.05 wt% CdCl₂ doped 90% Bi₂Te₃-10% Bi₂Se₃ single crystals were investigated. The Seebeck coefficient and electrical resistivity of the 0.15 wt% CdI₂ doped single crystals were initially decreased along the ingots due to the condensation of iodine in the melts. The sharp increase of the Seebeck coefficient and electrical resistivity at the last-to-freeze region were considered as results of the evaporation of iodine from the molten zone and the compensation of electrons due to the formation of the antistructure defects. The figure-of-merit was enhanced with increasing the zone melting temperature and lowering the growth rate. The single crystels grown at the zone melting temperature of 800℃ and the growth rate of 0.1 ㎜/min exhibited the maximum figure-of-merit of 2.8×10^(-3)/K.

BLT (Bi3.25La0.75Ti3O12) 박막의 결정립 배향성이 잔류 분극과 누설 전류에 미치는 영향

서주형,오상호,박찬향 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.11

Effect of grain orientation on the electrical polarization and leakage current characteristics of Bi_(3.25)La_(0.75)Ti₃O_(12) (BLT) thin films was investigated in terms of c-axis off alignment. The c-axis epitaxial and various c-axis off aligned BLT films have been successfully grown by using different electrode materials (Pt and SrRuO₃) and heat-treatments. In order to evaluate the crystallinity and the film texture of various c-axis off-aligned BLT thin films, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were carried out. BLT thin film grown on the SrRuO₃/SrTiO₃ (100) substrate revealed that its c-axis aligned completely parallel to the substrate normal, by developing cube-on-cube epitaxial relathionship with underlying SrRuO₃ film. The corresponding P-E curve showed nearly paraelectric property. The polycrystalline (117) and (014) oriented BLT films grown in this study were shown that their c-axis off alignment about growth direction increased by amount more than 50°. As the degree of c-axis off-alignment was increased, remanent polarization was increased due to the anisotropic polarization characteristic of BLT film, however, the surface roughness of BLT films was increased and it resulted in degraded leakage current characteristic. Therefore, grain orientation of BLT thin films is a crucial factor controlling the polarization properties and leakage current characteristics.

복사전열 가열로 튜브의 파손방지에 대한 연구

윤기봉,심상훈,유홍선,오현환 한국산업안전학회 1998 한국안전학회지 Vol.13 No.1

Radiant heater tubes with an inside burner are designed to transfer the heat generated from the burner to the outside of the tube by radiation. Hence, tube metal must suffer high temperature of approximately 900-1000℃. The radiant tube is usually manufactured by centrifugal casting with high Ni-Cr alloys. In this study, failure analysis results of the radiant tube arc reported. Failure mechanism of the tube was investigated by visual observation of the failed tube, metallographic study of the cracked region and chemical analysis of tube metal and oxide scales. It was argued that the main cause of the cracking is repeated oxidation of the tube metal located beneath the thick oxide scale. Oxidation was caused by abnormally high operating temperature which can be verified by aged microstructure and internal void formation.

C-Mn-Si 계 변태유기소성강의 성형상에 미치는 베이나이트 변태 온도 및 응력상태의 영향

박찬경,전현조,오진후,홍승갑 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.9

The effects of TRansformation Induced Plasticity(TRIP) phenomena on the plastic deformation of 0.2C-1.5Si-1.5Mn multiphase steel have been investigated at various heat treatment and stress conditions. In order to estimate a deformation behavior under multi-axial stress rotate, the hole expansion(HE) tests were carried out. It is shown that the formability evaluation from the uni-axial tensile tests was quite different from the formability measured from multi-axial HE-tests because of different stress state. The formability in the multi-axial stress state decreased due to the extinction of the transformable retained austenite at relatively earlier deformation stage and the production of irregular α' martensite. The voids of TRIP steel were initiated exactly at the interface between transformed martensite and ferrite matrix regardless of stress state. In addition, new form of experimental formula is proposed in order to predict the multi-axial formability of the TRIP steel from the results of uniaxial tensile test.

Sbi3 를 첨가한 25% Bi2Te3-75% Sb2Te3 와 15% Bi2Te3-85% Sb2Te3 단결정의 전기적특성과 열전특성

현도빈,황종승,심재동,오태성,하헌필 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.8

The temperature dependences of the electrical and thermoelectric properties of the SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 15% Bi₂Te₃-85% Sb₂Te₃ single crystals, grown by the Bridgman method, were measured at temperatures ranging from 77 K to 600 K. For the Sb₂Te₃-rich single crystals, the temperature dependence of the Hall mobility was T^(-1.0) regardless the Sb₂Te₃ contents and added amount of SbI₃. The temperature dependences of (m*/m_o)^(3/2)·μ_c and effective mass m*/m_o were T^(-1.5) and T^(-1/3), respectively. The decrease of the saturated hole concentration and the change of the slope of the Seebeck coefficient with temperature were considered in the view point of the two sub-bands in the valence band. The maximum figure-of-merit at 300 K of 0.2 wt% SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 0.4 wt% SbI₃-doped 15% Bi₂Te₃-85% Sb₂Te₃ single crystals were 2.25×10^(-3)/K and 1.95×10^(-3)/K, respectively.

승모판막 질환에서의 Doppler 심초음파도를 이용한 확장기 좌심방-좌심실 평균 압력차에 대한 연구

박영배,서정돈,이영우,김효수,도문흥,오병희 대한내과학회 1987 대한내과학회지 Vol.32 No.2

Diastolic LA and LV pressure gradient was determined with doppler echocardiography in 35 patients with mitral valvular heart disease and was compared with that determined with cardiac catheterization. In 23 patients who underwent mitral valvular replacement, pre and postoperative pressure gradients were observed, Correlation between pressure gradient and pressure half time was investigated with Doppler echocardiography. The results were as follows; 1) 1n total 35 patients with MVHD, mean ΔP in Doppler and cath were 15.8±6.3 (mean±S.D.) mmHg and 17.0±6.7mmHg, respectively, and the correlation coefficient was 0.91. 2) In 15 patients with pure MS, mean ΔP in Doppler and cath, were 15.5±6.1mmHg and 16.1±5.6mmHg, respectively, and the correlation coefficient was 0.90. 3) In 23 patients who underwent MVR, preop ΔP and postop Δ4P were 17.0±6.2mmHg and 2.2±0.9mmHg, respectively, and the difference was significant. 4) In 13 patients with Ionescu Shiley valve, ΔP and T were 2.1mmHgSl.lmmHg, and 110±50msec respectively. In 9 patients with St. Jude valve, ΔP and T1/2 were 2.3±0.7mmHg and 65±22msec, respectively, 5) The correlation coefficient between ΔP and T1/2 was 0.48 in total 35 MVHD and 0.57 in 15 pure MS. The correlation coefficient between ΔP divided by cardiac index and T1/2 f, was 0.63 in 15 pure MS. Therefore, Doppler echocardiography is a useful noninvasive diagnostic tool for measurement of the pressure gradient between LA and LV in MVHD, and can be used to assess the severity of preop, MVHD and postop. result and to follow up patients after operation.

(100-x)%Bi2Te3-x%Sb2Te3(x≥66.7) 단결정의 전기적 특성과 열전특성

현도빈,심재동,오태성,하헌필,한동균 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.11

Electrical and thermoelectric properties of the undoped (100-x)% Bi₂Te₃-x% Sb₂Te₃ (x≥66.7) pseudo-binary single crystals grown by the zone melting method were measured over the temperature range from 77 to 600K. For the (100-x)% Bi₂Te₃-x% Sb₂Te₃ (x≥66.7) alloys, the temperature dependence of the Hall mobility was T^(-1.0) regardless the Sb₂Te₃ contents. The temperature dependences of (m^*/m_o)^(3/2)·μ_c and the effective mass were proportional to T^(-1.5) and T^(-1/3), respectively. The saturated hole concentration decreased with increasing temperature and the slope of the Seebeck coefficient changed at about 350K, which implied the two sub-bands in the valence band. While the 33.3% Bi₂Te₃-66.7% Sb₂Te₃ alloy exhibited the highest figure-of-merit among the undoped Bi₂Te₃-Sb₂Te₃ alloys, the maximum figure-of-merit could be expected fur the 22.5% Bi₂Te₃-77.5% Sb₂Te₃ alloy with optimizing the carrier concentration.

매설 천연가스배관의 지반침하에 의한 응력 분석

홍성호,김우식,김형식,방인완,오규환 한국산업안전학회 1998 한국안전학회지 Vol.13 No.2

This study was initiated to examine the stress and deformation characteristics of the pipelines which were subjected to various environmental conditions in order to confirm their integrity. As the part of them, this paper presents the analysis results for the effect of ground subsidence combined with main loads on buried natural gas pipelines. The ground subsidence which can occur for buried gas pipeline has been classified to the three cases. Finite element method was used to analyze the effect of ground subsidences on pipeline of 26 inch(0.660 m) and 30 inch(0.762 m) diameter used as high pressure (70㎏_f/㎠(6.86 ㎫)) main pipelines of KOGAS. This paper shows the result of stress analysis for the pipelines subjected to those three case ground subsidence. Comparing these results with safety criterion of KOGAS(0.9 σ_y), maximum allowable settlement and loads have been calculated.