• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.1-6
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• 2011

In this paper, an 1.5Gbit/s wireless data transmission system using the carrier frequency of 300 GHz band was implemented. The RF front-end was composed of schottky diode sub-harmonic mixer, frequency tripler, and horn antennas for transmitter and receiver, respectively. The LO frequencies of sub-harmonic mixer are 150GHz for transmit chain and 156GHz for receive chain. The ASK(Amplitude Shift Keying) modulation was used in the transmitter and the envelope detection method was used in the heterodyne receiver. The conversion loss of sub-harmonic mixer and implementation system loss were measured to be 9.8dB and 1.2dB, respectively. The 1.5Gbit/s video signal with HD-SDI format was transmitted over wireless distance of 40cm without optical lens(4.2m with optical lens) and displayed on HDTV at the transmitted average output power of $20{\mu}W$.

• Product Safety
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• s.192
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• pp.30-33
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• 2009

대한민국 주부라면 누구나 알만한 제품. 물론 많은 제품들이 있겠지만 그 중 하나인 도깨비방망이... 주부들이 꼽는 주방 최고의 재주꾼은 무엇일까? 오븐, 가스레인지, 전자레인지, 냉장고$\cdots$주부라면 아마 '도깨비방망이'를 꼽을 것이다. 도깨비방망이는 지금까지 250만 대 이상이 팔린 대한민국 주부들의 대표적인 'MUST HAVE 아이템' 이다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.33-38
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• 1985

By the complemental frequency characteristics of directional filter in passband and stopband the method of isolation between microwave RF and low frequency If is derived. And when this characteristic of microstrip directional filter is applied to MIC balanced mixer from 3.7 to 4.2 GHz, the experimental results of isolation and return loss are more than 20 65 in this band. This balanced mixer with the microstrip coupled directional filter is suitable for the DBS microwave receiver system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.6
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• pp.479-486
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• 2008

The objective of this study is to investigate experimentally the characteristics of pressure drop in SMX type motionless mixers. The motionless mixers used are SMX-O, SMX-H, SMXL-O and SMXL-H ones. The SMX-H and SMXL-H mixer elements have been designed to reduce the pressure drop as compared with the SMX-O and SMXL-O ones. The Reynolds number based on the bulk average properties of the water is in a range of 5000 to 13000. The pressure drops across the motionless mixers are measured and the friction factors are calculated using the pressure drop data. On the average, the friction factors of the SMX-H and SMXL-H mixers are about 8% and 15% lower than those of the SMX-O and SMXL-O ones. In addition, the proposed correlations from the experimental data for the friction factor are presented and compared with those obtained from the literature.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1143-1150
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• 2001

In this paper, we designed a downconverter for K-band satellite multipoint distribution service(SMDS). The designed downconverter consists of a low noise amplifiers, bandpass filter, stable local oscillator, drain mixer and If Amplifiers. Low noise amplifiers show 28㏈ gain and 1.5㏈ noise figure in the frequency range of 19.2㎓~20.2㎓, and a band pass filter has a -l㏈ insertion loss, and 18.25㎓ Stable local oscillator which is dielectric resonant oscillation, We obtained that the output power of the 18.25㎓ oscillation frequency is 0.5㏈m and the phase noise is the -84.67㏈c at 10KHz offset frequency. With the input RF signal the 19.2㎓~20.2㎓, conversion gain of the drain mixer shows 5㏈ at the Intermediate frequency range of 950MHz~1950MHz. We have proved that the designed downconverter satisfied the specification of a K-band satellite multipoint distribution service and it can be applied to the satellite internet receiver.

• Tribology and Lubricants
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• v.35 no.1
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• pp.71-76
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• 2019

The differential planetary gear reducer as a main component of the concrete mixer driving mechanism requires a strong torque to mix concrete compounds. As this component is currently dependent on imports, it is necessary to develop it by conducting a study on vibration analysis and the resonance problem. The noise and vibration of a concrete mixer reducer increase owing to the transmission error of planetary gears, and the damage of components occurs owing to the problems in design and production. In this study, the tooth-passing frequency is calculated to evaluate the noise and vibration of a mixer reducer, and a fast Fourier transform (FFT) analysis is conducted through a vibration test using an acceleration sensor. The vibration of the reducer is measured at three points of input and output of the shaft and planetary gear housing with fixed and variable revolutions per minute. The operating conditions of gears and bearings are evaluated by performing the FFT analysis, and the resonance problem is verified. The results show that No. 1 pinion and ring gears revolve disproportionately. The amplitude values appear high, and the wear of tooth faces occur in tooth-passing frequencies and harmonic components of No. 1 and No. 2 pinion-ring gears. Therefore, we conclude that design changes in the reducer and a correction of tooth profiles are required.

• Proceedings of the Korea Association of Information Systems Conference
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• 1996.11a
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• pp.184-195
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• 1996

본 논문에서는 게이트의 길이가 0.25㎛인 GaAs HEM를 이용하여 11.7㎓-12.2㎓ 대역 위성통신용 수신기를 설계하였다. 설계된 수신기의전체이득은 38㏈이상, 잡음지수 1.8㏈이하, 입출력단의 반사손실은 -10㏈이하를 보였다. 수신기는 저잡음증폭기(LNA), 중간주파수증폭기(IFA), 믹서, 국부발진기(LO)로 구성되어 있으며 LO 주파수와 IF 주파수는 각각 10.75㎓와 0.95㎓-1.45㎓이고 칩의 크기는 1.7㎜×2.5㎜이다.

• Proceedings of the Optical Society of Korea Conference
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• 1990.07a
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• pp.133-138
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• 1990

점접촉 MIM (Metal-Insulator-Metal) 다이오드는 레이저 광속의 검출기, 고조파 발생기 및 믹서로 사용되며, 그 검출범위가 수십 THz의 주파수 영역까지 가능하다. 이러한 MIM 다이오드의 여러사기 변수들에 대한 감응도를 측정하였으며, 이들의 특성을 조사하기 위한 관원으로는 10P(36) line의 CO2 레이저 광속을 이용했다. 또한 제작된 점접촉 MIM 다이오드를 이용하여 두 CO2레이저 사이의 주파수 차이에 의한 맥놀이 주파수를 측정하였다. 그리고 MIM 다이오드에서 발견된 초퍼의 초핑 주파수에 의한 비선형 현상을 논하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.1 no.1
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• pp.119-233
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• 1996

본 논문에서는 게이트의 길이가 0.25$\mu\textrm{m}$dlsGaAs HEMT(High Electron Mobility Transistor)를 이용하여 11.7GHz-12.2GHz 대역 위성통신용 수신기를 설계하였다. 설계된 수신기의 전체이득은 38dB 이상, 잡음지수 1.8dB 이하, 입출력단의 반사손실은 -10dB 이하를 보였다. 수신기는 저잡음증폭기(LNA), 중간주파수증폭기(IFA) , 믹서(Mixer), 국부발진기(LO) 로 구성되어 있으며 LO 주파수와 IF 주파수는 각각 10.75GHz 와 0.95GHz-1.45GHz이고 칩의 크기는 1.7mm $\times$2.5mm이다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1996.10a
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• pp.184-195
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• 1996

본 논문에서는 게이트의 길이가 0.25um인 GaAs HEMT를 이용하여 11.7GHz -12.2GHz 대역 위성통신용 수신기를 설계하였다. 설계된 수신기의 전체이득은 38dB 이상, 잡음지수 1.8dB 이하, 입출력단의 반사손실은 -10dB 이하를 보였다. 수신기는 저잡음증폭기(LNA), 중간주파수증폭기(IFA) , 믹서, 국부발진기(LO) 로 구성되어 있으며 LO 주파수와 IF 주파수는 각각 10.75GHz 와 0.95GHz-1.45GHz이고 칩의 크기는 1.7mm $\times$2.5mm이다.