• 한국통신학회논문지
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• 제7권2호
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• pp.71-77
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• 1982

本論文은 X-Band마이크로波周波數領域에서 MIC平面magic tee를 利用하여 平衡mixer를 구현하는 方法을 提示한다. 이 magic-tee는 일찍이 Ronde에 의하여 마이크로스트립과 슬로트線路로서 실현할 수 있음이 提示되었으며 또한 이 magic-tee가 rat-race나 hybridring보다 좋은 特性을 가지고 있음이 確認되었다. 本硏究에서는 3rd order(E-arm)와 2nd order(H-arm)의 Chebyshev整合回路를 設計한 MIC magic-tee와 2개의 對稱特性을 갖는 Schottkey barrier 다이오우드로 平衡mixer를 製作한 結果 VSWR<1.2 및 conversion loss=6dB 程度의 廣帶域mixer가 됨을 確認하였다.

• 전기학회논문지
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• 제61권2호
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• pp.257-262
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• 2012

The Ministry of Information-Communication assigned 18~19GHz frequency band for communication of cabins and platform to link between subway/train and it's station. In this paper, we propose wireless transmission devices which are 2 stage hybrid low noise amplifier of 18GHz band and mixer for 18GHz as well to apply for RF receiver. We designed LNA to be noise matched its 1st stage and gain matched for 2nd stage and mixer using $180^{\circ}$ hybrid coupler to suppress the spurious signal. The transistors of 18 GHz LNA and mixer are NE3210S01 of NEC and KMB-N51-1, respectively. As the result of simulation, we get 19.92dB gain and 2.06dB noise figure with LNA and 8.61dB conversion loss with mixer.

• 한국위성정보통신학회논문지
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• 제11권1호
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• pp.1-5
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• 2016

본 논문에서는 L-Band 대역의 항행안전시설(DME, TACAN)에 적용 가능한 광대역 High power pulsed amplifier를 구현하였다. L-Band 대역의 항행안전시설의 특성상 구현된 SSPA는 매우 높은 출력과 선형성, 효율 특성을 요구한다. 이에 본 논문에서는 변형된 class F 기법을 이용하여 효율 특성을 개선하였다. 또한 hybrid coupler를 이용한 Balance 구조와 구동부 증폭단의 비선형 특성을 이용한 anti-phase 기법, 출력부 harmonic trap 등을 이용하여 선형 특성을 개선하였다. 구현된 SSPA는 약 300MHz의 대역폭을 가지며, 1.5KW 출력과 55%의 효율 특성을 보였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년 추계학술발표대회 개요집
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• pp.253-255
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• 2006

Grey relational analysis has been carried out to develop a new approach for optimization of Nd:YAG laser and MIG hybrid welding parameters. The quality of welded material depends on welding parameters. The parameters chosen for current study include wire type, shielding gas, laser energy, laser focus, traveling speed, and wire feed rate. The welding experiments were performed on 6K21-T4 aluminum alloy sheet. Functional demands on products may vary widely depending on their use. The ultimate tensile stress, width, and penetration were chosen as the optimization criterion. Practice based on an orthogonal array which is following Taguchi's method has been progressed. Base on the results of grey relational analysis, the optimal process parameters were obtained. This integrated work was judged and it is observed that the results obtained by using the optimal parameters are much improved compared to those obtained through initial setting.

• 소음진동
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• 제8권1호
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• pp.81-86
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• 1998

A 500Wh class high-speed Flywheel Energy Storage System (FESS) driven by a built-in BLDC motor/generator has been designed, which runs from 30000 to 60000rpm nominally. Due to the motor/generator inside, the flywheel rotor made of composites supported by PM/EM hybrid bearing system has a shape of bell or pendulum and thus requires accurate rotordynamic analysis and prediction of its dynamic behavior to secure the operating reliability. Rotordynamic analyses of the flywheel rotor-bearing system revealed that the bell shaped rotor has two conical rigid-body modes in the system operating range and the first conical mode, of which nodal point lies in the radial EM bearing position, can adversely affect the dynamic response of the rotor at the corresponding critical speed. To eliminate the possibility of wild behavior of the rotor, two guide bearings are adopted at the upper end of the rotor and motor/generator. It was also revealed that the EM bearing stiffness if 0.5~1.0E+6 N/m and damping of 2000 Ns/m are favirable for smooth operation of the system around the 2nd critical speed.

• 한국가시화정보학회지
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• 제6권2호
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• pp.3-8
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• 2008

A new 3D-PTV algorithm(a Volume PTV) based upon a hybrid fitness function has been constructed. A coherency fitness function is introduced using the information of space and time to sort out the correct particle pairs between the two camera images. The measurement system consists of two-high-definition-cameras($1k{\times}1k$), a Nd-Yag laser and a host computer. The developed algorithm has been employed to investigate the flow features of the cylinder wake. The Reynolds numbers with the cylinder diameter(d=10 mm) are 360, 540, 720, 900, 1080 and 1260. Two-dimensional displacements of the particles of each camera's image and neighbouring constraints were introduced to reduce the calculation loads. More than 10,000 instantaneous 3D vectors have been obtained by the constructed algorithm. The constructed algorithm could recover more than $80{\sim}90%$ of the particle numbers in the image condition.

• International Journal of Industrial Entomology and Biomaterials
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• 제12권2호
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• pp.95-100
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• 2006

Central Sericultural Research and Training Institute, Mysore have evolved several highly productive bivoltine hybrids which can produce international grade raw silk. Among them $CSR2{\times}CSR4,\;CSR2{\times}CSR5,\;CSR3{\times}CSR6,\;CSR17{\times}CSR16,\;CSR18{\times}CSR19$ and $CSR12{\times}CSR6$ are being popularized in the field. There is a minimum difference in their economic characters but they appear to differ in survival. Though they are productive under high input management conditions, they are very susceptible to different diseases under normal rearing practices. No systematic attempts have been made to test their susceptibility status / resistance. Thus the present study is a modest attempt to screen the above six productive bivoltine hybrids to two important pathogens viz., Bombyx mori Nuclear Polyhedrosis Virus (BmNPV) and Bombyx mori Infectious Flacherie Virus (BmIFV) along with existing hybrid, $KA{\times}NB4D2$ to assess their susceptibility / resistance. The results shows that the productive hybrid $CSR2{\times}CSR4$ is the most resistant to BmNPV and it is suggested by its highest $LC_{50}$ value followed by $CSR12{\times}CSR6,\;KA{\times}NB4D2,\;CSR3{\times}CSR6,\;CSR17{\times}CSR16,\;CSR18{\times}CSR19,\;CSR2{\times}CSR5$. Based on the $LC_{50}$ value and $LT_{50}$ values for BmIFV, the hybrid $KA{\times}NB4D2$ was found to be the most resistant (1st position) one followed by $CSR3{\times}CSR6$ (2nd position) $CSR2{\times}CSR$ (3rd position) and $CSR12{\times}CSR6$ (4th position) $CSR17{\times}CSR16$, $CSR18{\times}CSR19$ (5th position) and $CSR2{\times}CSR5$ being the least. The response of 7 bivoltine hybrids to both the pathogens BmNPV and BmIFV indicates that, the hybrids $CSR2{\times}CSR4$, $CSR12{\times}CSR6$ and $KA{\times}NB4D2$ were found to be the most resistant when compared to others. Further, $KA{\times}NB4D2$ being less productive hybrid with a shell ratio of 20.08%, the other two hybrids $CSR2{\times}CSR4$ (Cocoon shell ratio, 21.44%) and $CSR12{\times}CSR6$ (cocoon shell ratio, 23.45%) can be considered to be most productive with superior quality cocoon and resistant to both BmNPV and BmIFV pathogens. The overall study indicated that the hybrid $CSR2{\times}CSR5$ is the most susceptible hybrid to both the pathogens.

• 자원리싸이클링
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• 제23권2호
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• pp.3-16
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• 2014

탄산가스 삭감과 자동차 연비를 향상시키기 위한 자동차의 경량화는 현시대적 큰 과제이다. 경량화를 위하여 Hybrid Electrical Vehicle(HEV), Electrical Vehicle(EV)의 고성능 모터용 Nd 자석, Li이온 2차전지 및 배기가스 정화용 PGM촉매의 성능개발이 활성화 되고 있다. 우리나라는 자동차 경량화와 기능 향상을 위하여 사용하는 희소금속을 자원이 편재되어 있는 중국 등에서 수입하기 때문에 수출국의 공급 조절, 가격 폭등 등으로 수급이 불안정한 경우가 있다. 이를 대비하여 차세대 자동차에서 배출되는 폐 희소자원을 리싸이클링 할 필요가 있다. 본고는 리싸이클링 기술과 현상에 대하여 조사 분석한 정보를 기술자나 연구자에게 전해주어 국가 자동차 산업 발전에 기여하는데 목적이 있다. 조사 결과, 폐 자동차에서 배출되는 고성능 모터, 배기가스 정화용 백금족금속(PGM) 폐촉매, Li이온 배터리 등의 리싸이클링기술은 전처리 기술과 후처리 기술로 분류하는데, 전처리 기술인 기계적 분리 선별 기술은 연구 개발 중이며, 후처리기술인 습, 건식 제련 기술은 확립되어 있다. 리싸이클링 경제성 측면에서 폐 부품의 기계적 선별 기술에 대하여 집중적으로 연구할 필요가 있다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권11호
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• pp.601-611
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• 2002

As resent trends in structural construction have been to build taller and larger structures than any time in the past, they have had high flexibility and low damping that can cause large vibration response under severe environmental loading such as earthquakes, winds, and mechanical excitations. The damper with mass and sqring is one aproach to safeguarding the structure against excessive vibrations. In this paper, a large capacity hybrid-type linear motor damper(LMD) was designed and fabricated for the application to the vibration control of a large building structure model. It has been designed to be able to move the damper mass, 1,500 kg up to ${\pm}250mm$ strokes at the first mode natural frequency of the building structure model, ${\pm}0.51Hz$. Linear motor is consisted of the fixed coil and the movable NdFeB permanent magnets field part. The PM field part composed magnet modules and iron yoke, is the damper mass itself, 1500kg. LMD therefore has a simplified structure and requires a few elements in the driving system, being compared with a rotary motor damper and a hydraulic damper. However, the manufacture of large PM linear actuator is difficult because of the limit of PM size and the attraction and repulsion at the assembly of PM. Therefore, large damper system is manufactured and tested for dynamic characteristics and frequency response.

• 농업과학연구
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• 제36권2호
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• pp.123-127
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• 2009

본 실험은 신품종 대학찰 골드 1호에 대한 파종 시기별 생육 및 이삭 특성에 대한 연구 결과 주요 특성은 다음과 같다. 1. 공시종에 대한 간장은 모든 파종 시기에서 대학찰 골드1호가 찰옥 1호보다 컷으나 찰옥 1호의 개체간에는 생육 차이가 큰 변이를 보였다. 2. 공시종의 평균 개화기는 대조구인 찰옥 1호가 7일 정도 빨랐으나 개체간 차이가 큰 반면에 대학찰 골드 1호의 개화기는 균일하였다. 두 품종 모두 파종시기가 늦어질수록 개화 소요일수가 빨라지는 경향이었다. 3. 공시종에 대한 간장과 착수고의 비율은 파종시기가 빠를수록 두 품종 모두 낮게 나타나 도복 경감 효과가 클 것으로 나타났다. 4. 공시종에 대한 이삭길이 및 착립 상태를 비교한 결과 대학찰 골드 1호를 4월 말에서 5월 초에 파종한 것이 다른 시기에 파종한 것보다 생육 및 이삭 특성이 우수하였다.