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      • KCI등재

        초음파 에코파형의 웨이브렛 변환과 비파괴평가에의 응용

        박익근,박은수,안형근,권숙인,변재원 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.6

        초음파 에코파형의 시간-주파수해석법으로 Wigner 분포와 웨이브렛 변환 등과 같은 새로운 신호처리 기법이 비파괴평가 분야에 널리 응용되고 있다. 본 연구에서는 웨이브렛 변환(Wavelet transform)에 의한 음속과 감쇠계수의 주파수의존성과 초음파 결함신호의 잡음제거의 유용성 유무를 실험적으로 검증하였다. Gabor 함수를 웨이브렛의 기본 함수로 사용하였다. 초음파의 에코파형에 포함된 각 주파수성분의 속도와 감쇠계수의 주파수의존성을 추정할 수 있었으며, 초음파탐상에서 결함의 검출능 향상과 결함크기 산정의 정량화에 접근하기 위해 웨이브렛 변환에 의한 S/N 비신호처리 시뮬레이션 결과를 오스테나이트강 스텐인레스 용접부에 가공한 EDM 노치의 초음파 결함신호에 적용한 결과 임상에코를 저감하고 S/N 비를 개선하는 것이 가능하였다. Recently, advanced signal analysis which is called "time-frequency analysis" has been used widely in nondestructive evaluation appications. Wavelet transform(WT) and Wigner Distribution are the most advanced techniques for processing signals with time-varying spectra. Wavelet analysis method is an attractive technique for evaluation of material characterization nondestructively. Wavelet transform is applied to the time-frequency analysis of ultrasonic echo waveform obtained by an ultrasonic pulse-echo technique, In this study, the feasibility of noise suppression of ultrasonic flaw signal and frequency-dependent ultrasonic group velocity and attenuation coefficient using wavelet analysis of ultrasonic echo waveform have been verified experimentally. The Gabor function is adopted the analyzing wavelet. The wavelet analysis show that the variations of ultrasonic group velocity and attenuation coefficient due to the change of material characterization can be evaluated at each frequency. Furthermore, to assure the enhancement of detectability and flaw sizing performance, both computer simulated results and experimental measurements using wavelet signal processing are used to demonstrate the effectibeness of the noise suppression of ultrasonic flaw signal obtained from austenitic stainless steel weld including EDM notch.

      • 단일층 다결정 실리콘 플래시 EEPROM 셀의 설계, 제작 및 전기적인 특성 분석

        박근형 충북대학교 컴퓨터정보통신연구소 2012 컴퓨터정보통신연구 Vol.20 No.1

        In this paper, a new single polysilicon flash EEPROM's cell with a select transistor was proposed. The device was designed and fabricated using the Hynix 0.35 μm CMOS processes, and then the electrical characteristics of the fabricated devices were measured. From the measurement results, it was found that the devices showed very excellent performance of the program, the erase and the read operations. In addition, the devices showed very excellent endurance characteristics. Therefore it is sure that the single polysilicon flash EEPROM's cell proposed in this paper can be adequate for an embedded EEPROM device in the future.

      • 공동주택 리모델링 공사 시 거주문제 해결방안 사례비교 및 이에 관한 인식조사 연구

        박근형,박현석,김용수 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1

        The purposes of this study are to investigate and survey the solutions for the dwelling Problem during apartment buildings' remodeling period. The research method of this study includes case studies and a questionnaire survey from apartment residents. Through the research 3 moving options are investigated based on case studies and questionnaire survey, and finally the selection priority of the options is suggested.

      • KCI등재

        사지의 급성동맥 색전증에 대한 응급동맥 색전제거술

        박철완,원형섭,박정배,이근,조상훈,표창해,김상일 대한응급의학회 1996 대한응급의학회지 Vol.7 No.2

        Acute arterial occlusion of the extremities is often a surgical emergency and is due mostly to arterial embolus. It has infrequently been reported in the emergency department. Cardiac embolism is most commonly the result of atrial fibrillation secondary to valvular heart disease followed by ischemic heart disease. The emergency arterial embolectomy by Fogarty balloon catheter works well when the cause of occlusion is cardiac embolus obstructing normal vessels in a patient with valvular heart disease. Recently we met some patients with acute critical ischemia of the extremities due to arterial emboli in our emergency department. On physical examination, they all had symptoms of 5"P"s(pain, pallor, pulselessness, paresthesia, paralysis). After emergency arterial embolect omy, immediate improvement was observed in all patients. They were discharged within 1 week. We report our experiences with the review of literatures.

      • 금속-산화막-반도체 전계효과 트랜지스터(MOSFET)의 정전용량-전압(C-V)특성에 대한 연구

        박창엽,안형근 연세대학교 산업기술연구소 1985 논문집 Vol.17 No.2

        In Metal - Oxide - Semiconductor Field Effect Transistors the current - voltage(I-V) characteristic and the gain were tested for various channel lengths and geometries. The capacitance - voltage characteristics were also tested for both MOSFET and simple MOS structure, and compared with each other at various temperature. The compared results showed that the most stable I-V characteristic was observed in circular geometry, the second was winding geometry and the third was straight geometry. MOSFET with shorter length has more stable characteristic especially in the N-channel type than in the P-channel type. Transconductance ?? of samples were measured in the range between 0.06[??] and 0.93[??]. It turned out that the N-channel type has higher breakdown voltage than the P-channel type. In C-V measurements the threshold voltage of simple MOS structure was -4.5[v] in N-type and -2.75[v] in P-type, while the voltage of diffused type was -3.87[v] in N-type and -2.3[v] in P-type.

      • KCI등재후보

        공기 중 toluene diisocyanate의 포집방법에 따른 요중 toluene diamine의 관련성

        박근철,김치년,김현수,김형렬,노재훈 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.1

        Toluene diisocyanate(TDI) has been known the materials which is induced occupational asthma, is mostly used by the materials of industrial polyurethane, excreted as toluene diamine(TDA) in case of occurring metabolism in the human body when it inhaled. This research is demonstrated to make scrutiny into efficiency of two differentways of sampling in comparison with the cocentration after make use of the open cassette holder and the modified 2-piece cassette holder which are originaly existing to doing sampling 2,4-TDI as 2,6 TDI in the air, and to present more adequate way to TDI sampling in the air and to present more adequate way to TDI sampling in the air from comparing concentration TDA in a worker's urine with concentration of TDI which is being sampling each ways And this study want to grasp the influence for TDA excretion by exposing TDI from the general character of workers. The study was experimented on the 22 workers from the factory where is pperated paining work using by paints from poly urethane. This study was performed to identify the personal character of workers by using the questionnaire. analysed TDI from 44 sample each in the middle of morning and afternoon and TDA from the 17 workers by take their urine. Open cassette holder is manufactured to face the filter with the outside by remove the modified 2-piece cassette holder eliminated he middle of section and top of the upper holder. As a result of analysis, the concentration of TDI in the air is higher on the mokigied 2-piece cassette holder than the open cassette holder for sampling, There was no different on the concentration of urinary TDA by personal character. The concentration of TDI in the air had a relation with the concentration of urinary TDA no matter what kind of sampling method used, but the sampling by modified 2-piece cassette holder had more relation than sampling by open face cassette holder. As a result of this experiment, the concentration of TDI by sampling from the each cassette holder has shown to us significant relation with the concentration of urinary TDA.

      • 형질전환 담배 식물체에서 개똥쑥 Terpene Synthase의 발현

        박성길,홍성현,최근원,이윤형,정인식 경희대학교 생명자원과학연구원 2002 硏究論文集 Vol.22 No.-

        Expression of Artemisia annua terpene synthase in transgenic tobacco plants was examined. A full length cDNA encoding terpene synthase was cloned into pILTAB357 vector and transgenic tobacco plants were generated. The integration of this gene was analyzed by genomic DNA PCR and Southern blot analysis. The transcription of the terpene synthase gene in tobacco was confirmed by RT-PCR and northern blot analysis.

      • 결핵성 육아종에서 Thioredoxin peroxidase-2 의 발현

        박근호,유형륜,정영진,윤기중,한원철,유대열,문형배 圓光大學校 醫科學硏究所 1999 圓光醫科學 Vol.15 No.2

        Background: Thioredoxin peroxidase(TPX) is a kind of recently discovered antioxidant enzyme which react as rapid hydrogen ion donor for the removal of hydroperoxide. The action and distribution of the TPX was poorly understood in the human diseases. This experiments were designed for the study about the distribution of the TPX in the chronic granulomatous inflammation and about the correlation between the expression of TPX and the site of inflammation, histological activities of tuberculous inflammation or existence of mycobacterium in the inflammatory foci. Methods: The immunohistochemical stains were performed for the localization of the TPX-2 in the epithelioid cells, giant cells and lymphocytes in the chronic granulomatous inflammation. The tissue sections were obtained from the paraffin blocks of the 54 cases of tuberculosis (lung 21 cases, lymph node 12 cases, bone and soft tissue 12 cases, kidney 9 cases; active 33 cases, inactive 21 cases by the histologic classification; presence of mycobacterium 15 cases, no mycobacterium 39 cases by PCR reaction). Results: The expression of TPX-2 was 16.7% in the giant cells, 27.8% in the epithelioid cells and 100% in the lymphocytes of tuberculous inflammations. The expression of TPX-2 in the giant cells and epithelioid cells of the tuberculosis were 28.6% and 57.1% of the pulmonary tuberculosis; 33.3% in each cells of the renal tuberculosis; 0% in each cells of the lymph node or bone and soft tissue tuberculosis. The expression of TPX-2 in the giant cells and epithelioid cells were 9.1% in each cells of the active tuberculosis and were 28.6% and 57.1% in each cells of the inactive tuberculosis by histologic classification. The expression of TPX-2 in the giant cells and epithelioid cells was 40% in each cells of tuberculosis which mycobacteria were detected and the expression of TPX-2 was 7.7% and 23.1% in each cells which mycobacteria were not detected by PCR reaction in the paraffin embedded tissue. Conclusions: The above results were summarized that the TPX-2 in the giant cells and epithelioid cells were more frequently expressed in the inactive tuberculosis than in the active tuberculosis. These results suggest that the TPX-2 is a kind of regulating or suppressing factors in the activity of the tuberculosis.

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