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      • KCI등재후보

        광섬유센서에 의한 간이 비접촉 표면조도 측정기의 개발

        홍준희 대한공업교육학회 2009 대한공업교육학회지 Vol.34 No.2

        The purpose of this study was to develop the handy non-contact measurement device of the surface roughness by using the optical fiber sensor. The advantages of fiber optic sensors are high-speed responsibility, non-effect of the magnetic, convenience of the product and high precision. The measurement theory for surface roughness of optical fiber sensor is one to one correspondence between the reflected light intensity based on the surface roughness of the object and the measurement value of previously known for surface roughness. The reflected light intensity was determined using the distance to the surface from the sensor probe and the limit reflection angle based on the surface roughness. Therefore, in this study, the sensor probe was produced for determining the value of surface roughness only using the limit reflection angle based on the surface roughness with the fixed distance from the surface. A prototype measurement system was composed of a transmitting part, a receiving part and a signal processing circuit. The materials of standard measurement which was used in this experiment were SM45C, STS303 and Al60. According to the results of this study, approximation surface roughness formulas which was deduced from the correlation of between the standard surface roughness and the sensing output were verified that they were effect against the surface roughness measurement value of the option sample. And handy optical fiber surface roughness measurement device which was produced by an order was verified that it was effect for measuring of the precision surface roughness. 본 연구는 광섬유센서를 이용하여 표면조도의 간이 비접촉 측정기를 개발하 는데 목적이 있다. 광섬유 센서의 장점은 우수한 고속 응답성, 자기의 무영향, 제작의 편이성 이다. 광섬유센서 표면조도 측정 원리는 측정물의 표면조도에 따라 반사되는 광의 세기와 기지의 표면조도 값을 일대일 대응시키는 것이다. 반사광의 세기는 센 서 프로브로부터 표면까지의 거리와 표면조도에 따른 반사한계각에 따라 결정 되는데 본 연구에서는 표면까지의 거리를 일정하게 하여 표면조도에 따른 반 사한계각만을 가지고 표면조도가 결정되도록 측정 프로브를 제작하였다. 측정 시스템은 발광부, 수광부과 신호처리부로 구성되었다. 이 실험에서 사 용된 표준 측정 재료는 SM45C, STS303과 Al60이었다. 연구결과 첫째, 재료에 따른 표면조도와 센서출력의 상관관계로부터 근사표 면조도식을 도출하고 임의 가공된 시료의 표면조도 측정을 통해 근사표면조도 식이 유효함을 입증하였다. 둘째, 실제 제작한 간이 광섬유센서 표면조도 측정 기가 유용함을 입증하였다.

      • KCI등재

        NPN 트랜지스터를 이용한 검전기 제작

        홍준희,김중복 한국현장과학교육학회 2017 현장과학교육 Vol.11 No.3

        The metal leaf electroscope is mainly used for experiments about static electricity in middle or high schools. However, students have evident difficulty in interpreting how a leaf electroscope works. It is not only easy to adapt the general explanation of electrostatic phenomena by the electroscope, but the proper interpretation even at an elementary level is also relatively complex process. An electrometer using a VMOS Power FET has been developed and proposed for various electrostatic experiments. However, the VMOS in the electrometer can become a “black box” because students have difficulty to understand all the electronic principles involved. Also, it is not easy to obtain a commercial VN10KM product in a Korea market. This study propose a method to make a electroscope using an npn transistor, which is easy to obtain at any place, and compare the electroscope using the npn transistor with the electrometer using the VMOS Power FET. Finally we suggest an inquiry class in which students can use the npn transistor electroscope. 중∙고등학교에서 정전기에 대한 실험을 할 때 주로 사용하는 것이 금속 박막 검전기이다. 그러나 학생들이 금속 박막 검전기에서 박막의 움직임을 명확하게 해석하는 것은 결코 쉽지 않다. 정전기에 대한 일반적 설명을 검전기의 사례에 적용하는 것은 쉽지 않으며 기초적인 수준에서 조차도 검전기의 해석은 비교적 복잡한 과정이다. 이러한 이유로 VMOS Power FET를 이용한 검전기가 개발되었고 이를 활용한 다양한 정전기 실험이 소개된 바 있다. 그러나 학생들이 FET의 원리를 이해하는 것은 매우 어렵기 때문에 VMOS 검전기는 “블랙 박스”처럼 될 수 있으며 또한 검전기 제작에 사용한 VN10KM은 우리나라에서 구하는 것이 쉽지 않다. 이 연구에서는 어디서나 쉽게 구할 수 있는 npn 트랜지스터를 이용하여 검전기를 제작할 수 있는 방법을 제시하고, 이 npn 트랜지스터를 이용한 검전기와 FET를 이용한 검전기를 비교하였다. 끝으로 npn 트랜지스터를 이용한 검전기를 사용하여 학생들과 함께할 수 있는 탐구 수업을 소개한다.

      • KCI등재

        Synthesis of Novel 2'-Methyl Carbovir Analogues as Potent Antiviral Agents

        홍준희 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.2

        In this study, the synthesis procedures of 2'-branched carbovir analogues were accomplished. The introduction of a methyl group in the requisite 2'-position was carried out by the addition of a carbonyl using isopropenyl magnesium bromide. The desired compound, cyclopentenol 10(β), was synthesized via ring-closing metathesis using a second-generation Grubbs’ catalyst. The nucleosidic bases (adenine, cytosine, thymine, uracil, 5-fluorouracil and 5-iodouracil) were efficiently coupled using a Pd (0) catalyst. When the synthesized compounds were examined for their activity against several viruses, including HIV-1, HSV-1, HSV-2 and HCMV, the 5- iodouracil analogue, 23, exhibited significant anti-HCMV activity.

      • KCI등재

        엘리트 승마선수들의 요통여부에 따른 승마 구보와 속보 시 근활성도의 차이 분석

        홍준희,신윤아 한국사회체육학회 2020 한국사회체육학회지 Vol.0 No.82

        Purpose: The purpose of this study is to make a comparative analysis of muscle activity with or without low back pain (LBP) of elite equestrian riders according to the step of horse and to provide basic data designed for appropriate back pain prevention and management training program for elite equestrian riders. Method: This study was conducted on 14 elite equestrian riders. 7 prfoessional equestrian riders with or without LBP were selected respectively. The muscle activity acc ording to horse riding was measured during riding trot and canter. Results: Muscle activity of elite equestrian riders without LBP showed higher rectus abdominis (p<.01), rectus femoris (p<.05), tibialis anterior (p<.05), and lateral gastrocnemius (p<.05) compared to elite equestrian riders with LBP during riding trot. Also, the muscle activity fo elite equestrian riders showed a higher rectu s femoris (p<.05) compared to elite equestrian riders with LBP during riding canter. Conclusion: Therefore, these results indicate that elite equestrian ridesr with low back pain cannot properly use the muscles of the trunk and lower extremities during equetsrian exercise. It is considered that prope r prevention and management will be required.

      • KCI등재후보

        자기베어링 모니터링용 광파이버센서 개발에 관한 연구

        홍준희,한복수 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.1

        In a high speed spindle system, it is very important to monitor the state of rotating rotor. Particularly in active control spindle system, the position sensor must provide feedback to the control system on the exact position of the rotor. In order to monitor the state of a high speed spindle exactly, high accuracy and wide frequency bandwidth of sensors are important. The focus in this paper is to make a fiber optic sensor for monitoring rotor of magnetic bearing to design the circuit for detecting optical signal, and to evaluation static and dynamic characteristics of fiber optic sensor.

      • KCI등재

        2중 코어 구조의 소화기용 친환경 탄자 제조 및 특성 분석

        홍준희,장탁순,송창빈,강대화,Hong, Jun-Hee,Jang, Tak-Soon,Song, Chang-Bin,Kang, Dae-Wha 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.3

        This paper focuses on the properties analysis of 9mm bullet dual structure core to substitute current lead core by environment-friendly combination of W-Cu-Ni system high density composite materials. So the four combination samples were made of dual core with the different center of gravity location backward or forward compare to that of lead type bullet, and we experimented about the performance of 9mm bullet dual structure core. In the experimental results, the outer shape of core of four environment friendly samples on the target maintain marginally, while the current lead core bullets are completely crushed after hitting the target. The penetration depth of environment friendly samples excel seven times to lead type bullet and the three out of four samples with forward adjusted center of gravity penetrate deep as twice as ones backward. The impact tolerance of all four samples satisfies military specification, however, more firing tests are required to improve reliability of scattering distribution.

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