실리콘 직접 접합/전기화학적 식각정지를 이용한 실리콘 다이아프램의 형성과 실리콘 압력센서 제조에의 응용

김성환,주병권,김철주,차균현,오명환,하병주,김근섭,송만호 한국센서학회 1994 센서학회지 Vol.3 No.3

A new type of Si diaphragm was fabricated using Si-wafer direct bonding and two-step electrochemical etch-stopping methods. Using the new diaphragm structure in mechanical sensors, more precise control of cavity depth and diaphragm thickness was achievable. Also, the propagation of the stress, which was generated near the bonding interface, to the surface can be avoided. Finally, a piezoresistive-type Si pressure sensor was fabricated utilizing the diaphragm and a digital pressure gauge, which can display units of pressure, was realized.

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.

한국형 출혈열 후유증으로 발생된 만성 신우신염

김연수,한진석,이정상,김성권,진호준,안규리,오국환,오윤규 대한내과학회 1997 대한내과학회지 Vol.52 No.4

It has been known that most patients with Korean Hemorrhagic Fever (KHF) were recovered without any significant renal complication. But several cases of renal hypertension, chronic pyelonephritis, and chronic renal failure after KHF have been reported. Recently, we experienced one case of chronic pyelonephritis as a sequela of KHF, which has been diagnosed at the 78th month of illness. This case showed reduced thickness of renal parenchyme, small and irregular shaped kidney, focal loss of normal cupping of calyces, and accumulation of radiacontrast media at distal calyes by IVP. This case suggested that chronic pyelonephritis may develop as a sequela of KHF,

기관지내 전이암

김현수,이상수,오미희,이재갑,원구태,홍희승,용석중,신계철 대한내과학회 1991 대한내과학회지 Vol.40 No.4

The lung is the most common site of metastasis of extrapulmonary malignant tumor. According to past reports, metastatic cancer of the lung has been found in about 2% of all patients at autopsy. But these days, a diagnosis of endobronchial metastatic cancer utilizing bronchoscopy only is not easy. Thus we need other means of gathering more informaction, such as past history, discovery of other metastatic sites, and pathologic findings with special staining and electronmicroscope, especially in cases of poorly differentiated adenocarcinoma and epidermoid cancer, which are common types of primary lung cancer. We present 5 cases of endobronchial metastatic cancer. We found endobronchial metastatic cancer 2 cases of cervix cancer (epidermoid, adenocarcinoma), 1 case of colon cancer (adenocarcinoma), hypernephroma (renal cell carcinoma), and bladder cancer (transitional cell carcinoma). Since it was impossiole to diagnose the metastatic adenocarcinoma from the cervix only with lightmicroscopic findings, we could use past history and unusual radiologic and bronchoscopic findings which was thought to be the specific endoscopic finding of metastic endobronchial cancer. The interval between the diagnosis of the primary cancer and endobronchial metastatic cancer was 25.7 months. In the future, development of immunohistochemistry, monoclonal antibody, and molecular biologic techniques will give us diagnostic clue for differential diagnosis of metastatic endobronchial cancer from primary bronchogenic lung cancer.

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.

일부 영세 도금사업장의 국소배기성능과 공기중 총크롬 , 6가 크롬 및 니켈농도와의 관계분석

박동욱,박두용,신용철,오세민,정규철 한국산업위생학회 1993 한국산업보건학회지 Vol.3 No.1

To evaluate efficiencies of the local exhaust systems installed in chromium and nickel electroplating tanks, specifications of each tank and general performances of the local exhaust systems were measured in 16 electroplating plants from July 3 to November 24, 1992. Airborne concentrations of total chromium, hexa-chromium and nickel were also measured. Most of the local exhaust systems installed in electroplating plants were inadequately designed. Average capture velocities of local exhaust systems in chromium and nickel tanks were 0.45 m/sec and 0.29 m/sec. Average slot velocities in chromium and nickel tanks were 7.30 m/sec and 2.87 m/sec respectively. Both average capture and slot velocities were in noncompliance with the standards recommended by American Conference of Governmental Industrial Hygienists (ACGIH) and National Institute for Occupational Safety and Health (NIOSH). Exhausted air volume was insufficient in all local exhaust systems surveyed. Worker exposure levels to total chromium, hexa-chromium and nickel were 43.0 ㎍/㎥, 1.7 ㎍/㎥ and 9.3 ㎍/㎥, which were below the Korean Standard and U.S. Occupational Health and Safety Administration (OHSA) Permissible Exposure Limit (PEL). However, Worker exposure level to hexa-chromium exceeded the NIOSH Recommended Exposure Limit(REL) of 1 ㎍/㎥. As the result of Scheffee's multiple comparions, worker exposure levels to all metals were significantly different between two groups by the management state of existing local exhaust systems (p$lt;0.05). However, Difference between a group with local exhaust systems which were poorly managed and another group without local exhaust system was satatistically non-significant.

중탄소 Boron 강의 가스침질탄화처리에 의해 형성된 화합물층의 마모특성에 관한 연구

이상윤,이해우,조효석,이준범,박기원,오도원 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.2

The study on the wear characteristics of compound layers formed during gaseous nitrocarburising in the medium carbon boron steels and the plain carbon steel has been carried out by using a pin-on-disc type wear test machine under the oil lubricating condition at room temperature and by varying applied loads, sliding speeds and wear distances. Values of friction coefficient measured at the sliding speed of 0.4m/sec under the oil lubricating condition have been shown to decrease considerably with increasing applied load and become gradually a constant value as load is increased to a higher value, showing that the transition load for friction coefficient appears at an applied load of 247.2N. The length and volume wear rates of compound layer have been revealed to relatively constantly increase, also showing that the wear life per unit thickness of compound layer turns out to be superior as porous layer has a denser and thinner appearance. As the sliding speed increases during wear test performed by varying sliding speed at a load of 63.2N under the oil lubricating condition for medium carbon boron steel nitrocarburised in gas atmosphere, the wear rate has been found to increase, the friction coefficient to decrease and the wear life per unit thickness of compound layer to decrease considerably.

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.

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.