재발성 류마티즘 환자에서 발작의 유발인자

주유철,이동민,양종태,신병철,임태영,서정균,정기영,최동헌,김원,조영신,고희관 조선대학교 2001 The Medical Journal of Chosun University Vol.26 No.2

Background and Objectives : Palindromic rheumatism (PR) is known to be triggered without any obviously inciting events in most patients, although, in a few cases, attacks have been noted to relate to another events such as weather change, childbirth, ingestion of certain foods, or over-exercise. The aim of this study was to characterize the triggering factors on palindromic attacks. Materials and Methods : We evaluated sixty-four patients with PR for the presence of triggering factors and the relationship between attacks and triggering factors by interview of patients. We considered that there was an probable association between episodes and PR, if episodes within 24 hours prior to PR had triggered at least 50% of all attacks and a definite association between episodes and PR, if episodes within 24 hours prior to PR had triggered 100% of all attacks. Results : In 15 patients (35.9%), there was a possible association between episodes of PR and initiating events. In 8 patients (12.5%), there was a definite association between episodes of PR and initiating events. The triggering factors were physical over-activity including exercise (19/64: 29.7%), foods, such as rawfish, crab, and chicken, including alcohol (19/96: 19.8%). However, there were no difference between the groups with and without the triggering factor in sex ratio, duration and onset of PR, the positive rate of rheumatoid factor and involved sites. Conclusion : Our observations showed that PR was triggered by physical over-activity more than in previous reports and hypersensitivity to foods was a causative factor in some patients with PR. However, patients with triggering factors had a similiar clinical profile to patients without triggering factors.

유압관로에서 맥동유동의 유량특성

유영태,모양우,김지환 朝鮮大學校 機械技術硏究所 2001 機械技術硏究 Vol.4 No.2

The measurement of unsteady flow rate is importance to clarify and improve the dynamic characteristics in pipeline, hydraulic components and systems. There is also demand for a real time flow at the sensor in order to measure unsteady flow rate with high accuray and fast response to realize feedback control of flow rate in fluid power systems therefore We propose an approch for estimating unsteady flow rate through a pipeline and dynamic characteristics of pulsting flow rate components under high pressure condition. Unsteady flow rate is estimated by using semiconductor type pressure transducers and the measured pressure values at two distant points along the pipeline.

정사각 덕트의 출구 영역에서 속도분포에 대한 실험적 연구

유영태,모양우,나기대,임인호 朝鮮大學校 機械技術硏究所 2002 機械技術硏究 Vol.5 No.2

A numerical simulation has been performed with the non-linear turbulence model proposed by Speziale(1987) coupled with the k-ε equations coming from the renormalization group theory(RNG) derived by Yakhot et al(1992). The fully developed turbulent flow through a straight square duct, involing secondary motion is simulated. This paper represent computations of the interaction between measurement and numerical computation of turbulent flow on velocity distribution of outlet region in a square duct. RNG turbulent model was adapted and compared with the experimental data and the result of Standard k-ε turbulent model. The predictions obtained with the RNG k-ε model show improvements when compared with the Standard k-ε model. Mean velocity, turbulence kinetic energy and Reynolds shear stresses are in quantitiative agreement with the experimental data. We feel that the RNG k-ε model suggested in this paper can be a useful turbulence model for practical engineering

유압관로의 주파수변화 따른 압력전파특성

유영태,나기대,김지환 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.2

In this paper, an oil hydraulic pipeline is terminated by both rotary sinusoidal flow generator at upstream and oriffice at down stream. The pulsating pressure wave form, generated by the rotary sinusoidal flow generator, is measured by pressure sensor. In the analysis of this paper, a component of the fundamental frequency is obtained by using Laplace transformation. The experimental and analytical results make clear that (1) viscosity is significant role in hydraulic pipe. (2) When pulsating frequency is matched with the natural frequency, resonance frequency occurred periodically. According to the study proposed here, dynamic pressure in a circular oil pipe is expressed in propagation of pressure wave with respect to frequency and Bessel function. The resonance frequency is 108Hz at oil temperature 20℃ in this study. The abrupt change of gain value id due to effect of resonance frequency. The results of experiment are compared with the calculated results, and agreement of both results is fairly good.

압박 고 나사로 치료한 대퇴골 전자부 골절 : 고정 실패의 인자에 대한 분석 Analysis of Factors associated with Failure of Fixation

유찬훈,김홍태,변영수,남준모,조영호,문성건 대한골절학회 2002 대한골절학회지 Vol.15 No.4

목 적 : 압박 고 나사로 치료한 대퇴골 전자부 골절의 고정 실패에 영향을 미치는 요소에 대하여 분석하고자 하였다. 대상 및 방법 : 1995년 5월부터 2000년 7월까지 대퇴골 전자부 골절을 압박 고 나사를 이용하여 치료하고 1년 이상 추시가 가능했던 97예를 대상으로 하였다. 골절의 분류는 Jensen 분류법을, 골다공증의 정도는 Singh 지수를 이용하였다. 술후 방사선 검사에서 경체각, 정복 상태, 지연 나사의 대퇴골 두 내 위치, tip-apex distance(TAD) 및 지연 나사의 활강 거리를 측정하였고 고정 실패에 미치는 영향을 통계학적으로 분석하였다. 결 과 : 97예 중 17예(17%)에서 고정 실패가 발생하였고 그 중 지연 나사의 과도한 활강으로인한 경우가 15례(15.4%), 골두 천공 1얘, 10도 이상의 외반 변형 1예였다. 고정 실패의 발생과 80세 이상의 고령, 불안정성 골절, telescoping 정복, 원위 골편의 내측 혹은 전방 전위, 대퇴골 두 내 지연 나사의 위치와 밀접한 관계가 있었다. 결 론 : 압박 고 나사를 이용한 대퇴골 전자부 골절의 치료에서 고정 실패를 방지하기 위해서는 정확한 정복이 필요하고 대퇴골 두 내에서 지연 나사의 전방 위치를 피하는 것이 좋을 것으로 사료된다. Purpose : This study was performed to analyze the significant factors that may affect failure of fixation in trochanteric fractures of the femur treated with the compression hip screw. Materials and Methods : From May 1995 to July 2000, the authors analyzed 97 cases of trochanteric fracture of the femur treated with the compression hip screw and followed more than one year. We classified the fracture type by Jensen's method. We used Singh index for the degree of osteroporosis. In the post-operative radiograph, we checked neck-shaft angle, state of reduction, position of the lag screw within the femoral head, tip-apex distance, and sliding distance of the lag screw. The relationship between these factors and failure of fixation was statistically analyzed. Results : There were 17 cases(17.5%) of failure of fixation ; 15 cases(15.4%) of excessive sliding of the lag screw, 1 case (1%) of cutting out of the lag screw, and 1 case (1%) of valgus malunion. There were significant relationship between failure of fixation and old age over 80 , unstable fracture, telescoping reduction, anterior or medial displacement of the distal fragment, and anterior placement of the lag screw within the femoral head. Conclusion : Accurate reduction and avoidance of the placement of the lag screw in the anterior part of the femoral head were important factors to prevent failure of fixation in trochanteric fractures of the femur treated with the compression hip screw.

유압관로의 임피던스 전달특성

유영태,나기대,모양우,김지환 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

Design for quite operation of fluid power system requires t h understanding of noise and vibration characteristics of t h system This paper presents a dynamic response of design of hydraulic circuit. Experimental investigations on the attenuation characteristics of pressure ripple in automotive power steering hydraulic pipe with dynamic response of hydraulic pipe line is examined.

CW Nd:YAG레이저를 이용한 금형 재료의 표면열처리

유영태,신호준,장우양 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.5

Laser heat treatment is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power CO₂ lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching action to occur and the formation of matrensitic structure. In this investigation, the microstructrual features occurring in Nd:YAG laser hardening SM45C and STD_(11) steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimisation of the processing parameters for maximum hardened depth of SM45C and STD_(11) steel specimens of 10mm thickness by using CW:YAG laser.

간세포암의 십이지장침윤에 의한 상부위장관 출혈 1 예

유태현,한광협,박성하,김형길,문영명,한재호,조상호 대한소화기내시경학회 1999 Clinical Endoscopy Vol.19 No.2

Recent advances in both the diagnosis and treatment of hepatocellular carcinoma have improved the prognosis and changed the clinical significance of the recently increasing distant metastases. Distant metastases found after successful treament of the primary lesions are of great clinical significance for the treatment of hepatocellular carcinoma. The duodenum is a rare site of hematogenous metastases or direct invasion from hepatocellular carcinoma. A 23 year old man was admitted with upper gastrointestinal bleeding. He had been diagnosed with hepatocellular carcinoma and treated by a left lobectomy and chemoembolization. The patient was admittted for 12 months after the treatment of the primary tumor. Endoscopic examination revealed a mass in the duodenal bulb that protruded into the lumen. He died due to massive hematemesis. We report on a rare case of hepatocellular carcinoma with duodenal invasion in a 23-year-old male patient.

고출력 CW Nd:YAG 레이저를 이용한 인코넬 600의 용접 특성

유영태,신호준,임기건 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.6

The welding characteristics of Inconel 600 Alloy using a continuous wave Nd:YAG laser are experimentally investigated. The major process parameters studied in the present laser welding experiment were the positions of focus, laser power and travel speed of laser beam. We measured the fusion zone size and its shape using an optical microscope for the observation of cross-sectional area. We performed two tests regarding the tension and the micro hardness for welding quality estimation. Then we measured residual stress in welds by electronic speckle pattern interferometry(ESPI). In conclusion, the optimum butt welding process parameters were 0.5mm focus position, 1.6kW laser power, 1m/min travel speed and 5.5ℓ/min assist gas discharge.

유압관로에서 비정상유량의 속도분포에 대한 이론적 해석

유영태,조정규,최병재 조선대학교 에너지.자원신기술연구소 2001 에너지·자원신기술연구소 논문지 Vol.23 No.1

An efficient wave equation is analyzed for determining wave of taking into account viscosity and radial velocity and a oil hammer. Both frequency and transient response experiments are carried out with use of a rotary sinusoidal flow generator. The dynamic pressure of oil is measured and the obtained frequency characteristics are compared with the theoretical ones. Experimental and theoretical results make clear that the wave equation investigated here can predict wave phenomena in a wave transmission line containing a viscous liquid. i.e., in a hydraulic lines.