Correction to: Mode‑Change PWM Method for Improving Efficiency of 3‑Level T‑Type PWM Converter

Lee Woo‑Cheol,Kim Tae‑Hun 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1

마이크로波用 素子 特性化를 위한 Test Fixture 補正에 관한 硏究

신헌철,유영길 건국대학교 1991 論文集 Vol.32 No.1

To measure the active semiconductor devices for microwave, we fabricated the test fixture and cal. kit for it's characterization. OSL(Open, Short, Load)method was used to calibrate test fixture when the range of frequencies were 0.4 to 20GHz. We showed the de-embedding procedure to measure MIC, etc. The results for test fixture were obtained below 1.1 of the average VSWR and below - 20dB of the return loss.

수지진동증후군의 진단시 냉각부하검사에 의한 수지피부온도의 평가

유철인,이지호,이충렬,이헌,최영희,김양호 大韓産業醫學會 2002 대한직업환경의학회지 Vol.14 No.2

목 적 : 진동에 폭로된 근로자들을 대상으로 진동장해의 유무를 평가하고 냉각부하 후 수지피부온도를 측정하여 수지진동증후군의 유형별로 결과를 평가하여 향후 수지진동증후군 진단의 객관적인 지표로 사용하기 위한 기본적인 자료를 확보하고자 본연구를 실시하였다. 방 법 : 진동에 폭로된 근로자 58명을 대상으로 설문조사와 이학적 검사를 실시하였으며 Stock-holm-revised vibration syndrome classification system에 따라 근로자를 평가하였다. 평가 후 연구대상자들을 말초혈관증상군, 말초신경증상군, 특별한 중상이 없는 무증상군으로 분류하여, 10 ℃에서 10분간 냉각부하하면서 수지피부온도를 측정하고, 측정된 수지피부온도를 이용하여 5분 회복율과 10분 회복율을 산출하여 각 군별로 비교하였다. 결 과 : 연구대상자들을 분류한 결과 말초혈관장해를 호소하는 군이 33명이었으며, 말초신경장해만 있는 군은 18명이었으며, 특별한 증상이 없는 무증상군이 7명이었다. 수지냉각부하검사결과 냉각부하가 끝난 다음 5분, 10분 후에 측정한 피부온도와 5분 회복율, 10분 회복율은 혈관증상군이 신경증상군과 무증상군에 비하여 통계적으로 유의하게 낮았다(P<0.05). 결 론 : 냉각부하시 수지피부온도를 이용한 회복율은 수지진동증후군의 말초혈관장해 진단에 객관적인 지표로 사용할 수 있을 것으로 추정된다. Objectives : Various objective tests have been widely used worldwide for diagnosing the hand-arm vibration syndrome. Among these, the cold provocation test has been frequently used to confirm the presence of Raynaud's phenomenon. This study was carried out in order to evaluate finger skin temperature by cold provacation test(10 ℃ for 10 minute) for the diagnosis of hand-arm vibration syndrome Methods : Fifty-eight workers who had been to exposed local vibration were examined. Information concerning age, occupation, types of vibration tools used, presence of subjective symptoms such as vibration induced white finger(VWF), and numbness and tingling were collected. The subjects were classified into three groups according to their symptoms(Vascular, Neural, and No symptom group). In order to examine the applicability of the cold provocation test using water at 10 ℃ for 10 minute, we compared finger skin temperature between the groups. Results : The mean value of the finger skin temperature at 5 minutes and 10 minutes after cold provocation as well as the recovery rate in the vascular group were significantly lower than that seen in the other groups. Conclusions : The evaluation of finger skin temperature by cold provocation test is very useful method for the diagnosis of hand-arm vibration syndrome. The test results will assist in confirming the diagnosis of the hand-arm vibration syndrome.

DMB용 능동안테나 설계

신헌철 주성전문대학 2008 論文集 Vol.17 No.-

In this paper, we design antenna for DMB receiver using microstrip patch. To design patch antenna with circular polarization, we cut edges of rectangular patch, and then generate circular polarization. We compare the measured value of the designed antenna with its simulation result. Antennas for DMB receiver require 40MHz bandwidth at 2.642GHz in terms of lOdB bandwidth, VSWR of 1.5:1, input impedance of 50Ω and gain of -1.0dBi. We design patch antenna for DMB receiver which has 44MHz bandwidth at 2.642GHz, and antenna gains of -1.2dBi. We design low noise amplifier for DMB receiver. The fabricated LNA has NF characteristic of less than 1.6dB in the frequency band of 2.6GHz~2.8GHz. The measured gain of the LNA is 31dB.

Texture Pattern을 이용한 癌細胞의 認識

나철훈 木浦大學校 工業技術硏究所 2000 工業技術硏究誌 Vol.10 No.-

In this paper, a improved method of digital image analysis required in basic medical science for diagnosis of cells was proposed. The object image was the Thyroid Gland cell image, and the purpose was automatic discrimination of three classes cells(normal cells, follicular neoplastic cells, and papillary neoplastic cells) by difference of chromatic patterns. Feature parameter was obtained from discrete Fourier transformation of image. After construct a feature sample group of each cells, experiment of discrimination was executed. As a consequency of using features proposed in this paper, get a better recognition rate(70-90%) than previously repoted papers, and this method give shape to get objectivity and fixed quantity in diagnosis of cells.

구리 지역에서 조사한 고혈압의 인지도, 치료률 및 관리률

홍철호,김순길,홍택원,이제,신진호,이재웅,김경수,김정현,임헌길,이방헌 대한간질학회 2003 대한간질학회지 Vol.9 No.1

산소의 첨가가 박막 백금측온저항체의 온도저항계수에 미치는 영향

설철규,김영진,장경훈,이건환,이정희 경북대학교 센서기술연구소 1997 센서技術學術大會論文集 Vol.8 No.1

A thin film Pt-RTD(resistance temperature device) was fabricated by using DC magnetron sputtering and laser patterning. A study was fulfilled to adjust the TCR(temperature coefficient of resistance) to 3850 ppm/℃ which is IEC751 standard and the influence of oxygen addition(0 ~ 20 %) on TCR was measured. The resistance of Pt-RTD was set to 1000 Q at 0 ℃ using laser patterning and trimming. The analyses of XRD and AES were used to characterise the platinum thin film. The TCR of Pt-RTD was measured by a high precision oil bath. When the addition of oxygen flow rate was 1 %, TCR was 3850 ppm/℃.

EVA/MMT 나노복합체의 제조 및 열적, 기계적 성질에 관한 연구

전철환,류승훈 경희대학교 산학협력기술연구원 2001 산학협력기술연구논문집 Vol.7 No.-

Ethylene vinyl acetate copolymer and montmorillonite nanocomposites were prepared by melt intercalation using HAAKE mixer. The influence of substituted alkylamine in MMTs and molecular weight(melt index) of EVA on the intercalation behavior of EVA/MMT composites were investigated. EVA/MMT composites were analyzed by X-ray diffraction in order to study the changes of MMT interlayer distance. The dimethyl dioctadecyl ammonium ion substituted MMT can exist nano-scale in EVA. Thermal stability of composites is improved about 40℃, and the modulus increases twice for pristine EVA for 10 wt% MMT.

천수만층의 형성과 진화

이철우,백창훈,이동우 충남대학교 기초과학연구소 1995 연구논문집 Vol.15 No.-

천수만층은 백악기의 육성 퇴적물로 구성되어 있다. 퇴적작용은 주로 선상지에서 이루어졌다. 남북방향으로 발달하는 천수만층은 대규모 좌수향 주향이동 단층에 고각으로 발달하는 이차 단층계에 의하여 생성하는 것으로 추정된다. 전체적인 층후는 약 200∼300 m에 달하는 것으로 보인다. 층의 서측 경계는 단층으로 기반암과 접하며 동측은 바트리스(buttress)부정합과 단층으로 기반암과 접한다. 지질시대는 화산쇄설성 퇴적물이 전 지층에 걸쳐 고루 나타나는 것으로 보아 경상누층군의 하양층군에 대비되는 것으로 보인다. 천수만층 형성 초기의 퇴적작용는 넓은 지역에 걸쳐 박층으로 퇴적되었고 후기 침식 작용에 의하여 좁고 긴 형태로 나타나게 되었다. The Chonsuman Formation consists of Cretaceous non-marine sequences which were deposited in proximal to medial alluvial fan environments. The depression was probably by secondary fault of large-scale sinistral strike-slip fault system trending NE-SE. Distributary pattern of the Chonsuman Formation shows N-S trend. The total thickness of the formation reaches ca. 200-300meters. Western margin of the formation contacts with the Taean Formation by fault. Eastern one shows both fault and buttress unconformity. Based on the volcanogenic components broadly distributed on all sequence, it may be correlated largely with that of the Hayang Group. In the initial stage of the basin-formation, sedimentation was shallow an broad, and occupied in a narrow and long after erosion.

MRC 결합의 레이크 수신기에서 채널 추정 알고리즘의 성능분석

오동진,나철훈 국립7개대학공동논문집간행위원회 2005 공업기술연구 Vol.5 No.-

In this paper, we analyze channel estimation algorithms in a RAKE receiver with MRC. There are 3 popular channel estimation algorithms, which are WMSA(Weighted Multi-Slot Averaging) algorithm, EGE(Equal Gain Estimation) algorithm. and SSE(Symbol-to-Symbol Estimation) algorithm. We analyze asynchronous IMT-2000(3GPP) which employ 3 different channel estimation algorithms by using MATLAB. We used jakes fading channel model for the analysis. From simulation results, we could observe that the performance of WMSA algorithm is better than others in low Doppler effect(3km/h). However, in the case of high Doppler effect(120km/h), the EGE algorithm is more efficient. In this case the simple estimator with EGE algorithm seems to be more useful.