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      • [논문]Operational Characteristics of CO2 Laser Adopted by Superposing-Discharge

        Hee-Je Kim,Hyun-Ju Chung,Byoung-Dae Min,Jong-Han Joung,Sung- lun Park 釜山大學校生産技術硏究所 2003 生産技術硏究所論文集 Vol.62 No.-

        오늘날 현저한 CO2 레이저의 응용 추세에 발맞추어 보다 다양한 형태의 출력 제어 기술이 대두되고 있다. 본연구에서는multi-Pulse Superposing-Discharge 기술을 이용하여 다양한형태의 CO2 레이저의 펄스를 성형 하였다. 펄스 성형을 위한 방법으로 PIC one-chip microprocessor를 이용하여 삼중 PFN 모률의 SCR을 각각 고유의 지연시간을 가지도록 제어하였다. 실험에 사용된 삼중 PFN 모률의 전원 회로는 각각 캐패시터 인덕터,SCR,고압 펄스 트랜스 그리고 고압 트랜스 2차측에 브릿지 정류기로 구성 하였다. 고압 펼스 트랜스의 1차측을 제어하므로서 PFN 모률의 동작을 저 전압에서 수행 할 수 있다. 트랜스의 2차측에 연결된 전파 정류기는 펄스 에너지를 부하에 지속적으로 전달한다. 본 연구에서는 삼중 PFN 모률의 각각의 SCR을 다른 시간 가격을 두고 트리거 하므로서 다양한 Long pulse shaping을 실현하였다. 또한 약 250-1000μs 의 주기를 가지는 다양한 펄스형 레이저 빔을 얻었다.

      • 로보트 매니플레이트 적응모델 추종제어

        이병노,채창현,문영현 연세대학교 산업기술연구소 1986 논문집 Vol.18 No.1

        This paper presents the application of an adaptive model-following control(AMFC)technique for robotic manipulators. The control scheme is to minimize the state error which is the difference between the state of the reference model and the state of the controlled manipulator. The stability of the whole system was automatically guaranteed by the hyper-stability control structure. The upper three joint of a PUMA robot with six rotational joints was selected to investigate the practical applicability of the proposed adaptive controller. The effect to the payload change has been analyzed through the computer simulation of manipulator. The results agreed with the expected capabilities of the AMFC. The proposed AMFC contoller of robot manipulator ensures the adaptibility to spatial configuration and good insensitivity to the payload changes.

      • TMS DSP 칩을 이용한 음성 특징 벡터 추출기 설계

        예병대,현유진,성광수 嶺南大學校 工業技術硏究所 2002 工業技術硏究所論文集 Vol.30 No.2

        In this paper, we proposed speech feature vector extractor for embedded system using TMS 320C31 DSP chip. For this extractor, we used algorithm using cepstrum coefficient based on LPC(Linear Predictive Coding) that is reliable algorithm to be is widely used for voice recognition. This system extract the speech feature vector in real time, so is used the mobile system, such as cellular phones, PDA, electronic note, and so on, implemented voice recognition.

      • 전류측정에 의한 AC서보모터의 언밸런스 고장검출

        송명현,조병호,김부열 순천대학교 2000 순천대학교 자연과학논문집 Vol.19 No.1

        Using current measurement, the analytic method for the unbalance fault detection of 3Φ induction servomotor was proposed. The fault detection of the load unbalance has been studied by means of the measure of vibration. In the conventional method, the additional vibration sensors are set up to measure the vibration properly, but the method introduced in this paper, a current sensor for motor control is used for measuring the load current, so there is no need for additional sensors. After measuring the current caused by unbalance load, the FFT spectrum of the measared current were analyzed and compared with the spectrum pattern of the balanced load. Varying the motor speed by 500, 1000, 1500 and 2000 rpm, some characteristic frequency for detecting the unbalance fault were found. These experimental results show that the proposed current measuring method is more simple, easy, and effective than the conventional vibration measuring method.

      • KCI등재후보

        대구시의 지역별 생활쓰레기 성상 및 특성

        노숙현,이동훈,최충렬,박만,박병윤,최정 한국환경과학회 2003 한국환경과학회지 Vol.12 No.4

        This study was conducted to provide the basic information to know reasonable method for the removal and treatment of municipal solid wastes(MSWs). MSWs four different sources(apartment, residence, commerce, office/industry) in Daegu city were collected, and bulk density, physical composition, moisture, combustible, ash, elements and heating values were investigated. The values of bulk density were at range of 0.30~0.41ton/㎥. The percentages of foods, papers, vinyls/plastics, textiles, rubbers/leathers, metals and glasses/ceramics of wet muncipal solid wastes from three sources except office/industry were at range of 27.3~46.4&, 21.2~38.4%, 10.3~11.9%, 3.8~5.2%, 0.5~1.7%, 6.9~8.7% and 1.9~2.6% respectively. The percentages of papers, foods, vinyls/plastics, textiles, rubbers/leathers, metals and glasses/ceramics of dry muncipal solid wastes from three sources except office/industry were at range of 21.2~40.4%, 14.2~30.1% 15.2~17.8%, 4.0~6.0%, 0.9~2.8%, 12.2~14.1% and 3.1~3.7% respectively. The moisture contents of foods, woods, textiles and papers in wastes were at range of 65.7~76.2%, 34.6~50.0%, 22.2~44.8 and 30.6~44.4% respectively. The carbon contents of vinyls/plastics, rubbers/leathers, textiles, woods, papers and foods in wastes were at range of 75.88~79.87%, 58.24~70.74%, 45.23~51.63%, 42.29~45.58%, 40.19~48.4% and 25.86~36.25% respectively. The low heating values of foods, papers, woods, textiles, rubbers/leathers and vinyls/plastics by Dulong's law were at range of 178~1,353㎉/㎏, 770~1,660㎉/㎏, 995~1,629㎉/㎏, 2,133~2,432㎉/㎏, 4,200~7,275㎉/㎏ and 6,384~8,722㎉/㎏ respectively, and the high heating values of them were at range of 782~2,056㎉/㎏, 2,459~3,314㎉/㎏, 3,056~3,592㎉/㎏, 4,381~5,087㎉/㎏, 5,005~8,066㎉/㎏ and 10,032~10,739㎉/㎏ respectively.

      • 공간구조 분석에 있어서 GIS기술을 이용한 건축물 [근접성]의 정량화 방법에 관한 연구

        송병호,정명진,배상현 조선대학교 기초과학연구소 2003 自然科學硏究 Vol.26 No.-

        In this paper quantitative method about buildings and land use pattern is discussed by distance among near buildings(DNB). We considered the worth of DNB as urban planning method following two points : 1) DNB average and Building area ratio were pretty independent each other. That is to say DNB did not show density but arrangement. 2)DNB would express not just near buildings pattern and small vacant apace but also lot-street patterns. We analyzed following three steps. Firstly, we figured a calculating algorithm, secondly we analyzed characteristics of 4 index about DNB and statistical relations of DNB to building area ratio by each lot unit, thirdly we discussed combination patterns of DNB average and urban space pattern. The aim of this study is to theoretically develop a simple yet efficient system of data generation for urban planning and spatial structure analysis based on the application of GIS technique.

      • 모래다짐말뚝(SCP) 개량지반의 응력분담비에 관한 연구

        고영현,김병일,박용원 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

        Lots of soil improvement methods has been developed in order to increase soil properties of soft ground such as newly reclaimed land The sand compaction pile(SCP), which forms a composite ground by driving sand piles into soft ground, is one of the commonly used soil improvement techniques especially for soft clay deposit. In desinging SCP method, it is very important to determine the stress concentration ratio of composite ground. In this study, 3-dimensional analyses were carried out using single and group pile models to evaluate the stress concentration ratio with the area replacement ratio and the stiffness ratio. PENTAGON_3D software is used to analyze the composite ground using modeling with single pile of unit cell concept and group piles. As a result, the distribution of the predicted stress concentration ration with the stiffness ratio(Es/Ec) and the area replacement ratio is around 2.5 ~ 3.5

      • KCI등재

        산 완충용액의 pH 및 유산의 온도가 인공치근우식의 형성에 미치는 영향

        오현석,노병덕,이찬영 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.1

        치근 우식증은 복합적인 요인에 의해 발생되는 질환으로 고령인구의 증가로 최근 증가추세 에 있으나 아직까지는 병소깊이, 상아질 탈회의 정도 및 양상, collagen의 파괴 정도 및 수산화인회석 결정 변화에 대한 탈회 완충액의 조직학적 연구는 미비한 실정이다. 본 연구는 우식 형성에 영향을 주는 산 완충용액 내의 pH와 유산의 농도변화에 따른 치근 상아질 우식 병소의 진행에 미치는 변화를 편광현미경을 이용하여 관찰하고 관찰된 우식 병소층의 수산화인회석의 결정 형태 변화를 주사전자현미경으로 관찰하여 탈회 과정을 살펴보고자 세 가지 pH (4.3, 5.0, 5.5)군과 각각의 pH군에 세 가지 유산의 농도 (25 mM, 50 mM, 100 mM)를 이용하여 인공치근 우식을 형성한 후 비교 분석하여 다음과 같은 결과를 얻었다. 1. 편광현미경 소견에서 우식 병소의 깊이는 pH 보다는 유산의 농도에 의해 더 영향을 많이 받았다. 2. 주사전자현미경 소견에서 유산의 농도가 높아질수록 그리고 pH가 낮아질수록 수산화인회석 결정의 소실이 더 많이 진행되었다. 3. 탈회는 수산화인회석 결정의 변연부가 소실되며 결정 cluster내 결정의 숫자 및 크기가 감소하였고 결정 cluster 사이의 간격이 넓어지는 양상으로 관찰되었다. 4. 표면층에서의 주사전자현미경 관찰 시 유산의 농도가 높아질수록 수산화인회석 결정 cluster의 형태는 소실되고 콜라겐 섬유 표면에 수산화인회석 결정의 용해, 재결합된 양상으로 관찰되었다. 5. 탈회 과정에 대한 주사전자현미경 관찰 시 상아질의 탈회는 단순히 탈회만 독립적으로 일어나는 과정이 아닌 탈회와 재광화가 동시에 일어나는 양상으로 관찰되었다. 이상의 결과 산 완충용액 내의 유산의 농도가 높아지고 pH가 낮아질수록 탈회의 속도가 증가하고 탈회의 과정은 수산 화인회석 결정 cluster의 표면으로부터 진행되며 시간이 경과함에 따라 수산화인회석 결정의 형태는 원형 또는 타원형에서 불규칙한 형태로 변화되었다. The purpose of this study is to compare and to evaluate the effect of pH and lactic acid concentration on the progression of artificial root caries lesion using polarizing microscope, and to evaluate the morphological changes of hydroxyapatite crystals of the demineralized area and to investigate the process of demineralization using scanning electron microscope. Artificial root caries lesion was created by dividing specimens into 3 pH groups (pH 4.3, 5.0, 5.5), and each pH group was divided into 3 lactic acid concentration groups (25 mM, 50 mM, 100 mM). Each group was immersed in acid buffer solution for 5 days and examined. The results were as follows: 1. Under polarized microscope, the depth of lesion was more effected by the lactic acid concentration rather than the pH. 2. Under scanning electron microscope, dissolution of hydroxyapatite crystals were increased as the lactic acid concentration increased and the pH decreased. 3. Demineralized hydroxyapatite crystals showed peripheral dissolution and decreased size and number within cluster of hydroxyapatite crystals and widening of intercluster and intercrystal spaces as the pH decreased and the lactic acid concentration increased. 4. Under scanning electron microscope evaluation of the surface zone, clusters of hydroxyapatite crystals were dissolved, and dissolution and reattachment of crystals on the surface of collagen fibrils were observed as the lactic acid concentration increased. 5. Under scanning electron microscope, demineralization of dentin occurred not only independently but also with remineralization simultaneously. In conclusion, the study showed that pH and lactic acid concentration influenced the rate of progression of the lesion in artificial root caries. Demineralization process was progressed from the surface of the cluster of hydroxyapatite crystals and the morphology of hydroxyapatite crystals changed from round or elliptical shape into irregular shape as time elapsed.

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