• 대한기계학회논문집A
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• 제25권11호
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• pp.1829-1834
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• 2001

The aim of this study is to investigate the ductile fracture behavior under mixed mode (I/II) loading using SA533B pressure vessel steel. Anti-symmetric 4-point (AS4P) bonding tests were performed to obtain the J-R curves under two different mixed mode (I/II) loadings. In addition, the fractographic examination of fracture surfaces was carried out to compare with those of pure Mode I and Mode II. In conclusions, the J-R curves under Mixed Mode (I/II) loading were located between those of Mode I and Mode II loadings. When the mixture ratio of mixed mode (I/II) loading was high, the J-R currie of mixed mode (I/II) loading approached that of pure mode I loading after some amount of crack propagation. In contrast with the above fact, if the mixture ratio was low, the J-R curve looked after that of pure mode II loading. The fractographic evidences such as the shape of dimples under different loading conditions supported these conclusions.

• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.476-484
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• 2002

The aim of this study is to investigate the ductile fracture behavior under mixed mode (I/II) loading using SA533B pressure vessel steel. Anti-symmetric 4-point (AS4P) bending tests were performed to obtain the J-R curves under two different mixed mode (I/II) loadings. In addition, finite element analysis using Rousselier Ductile Damage Theory was carried out to predict the J-R curves under mixed mode (I/II) loadings. In conclusions, the J-R curves under. Mixed Mode (I/II) loading were located between those of Mode I and Mode II loading. When the mixity of mixed mode (I/II) loading was high, the J-R curve of mixed mode (I/II) loading approached that of pure mode I loading after some amount of crack propagation. In contrast with the above fact, if the mixity was low, the J-R curve took after that of pure mode II loading. Finally, it was found that the predicted J-R curves made a good agreement with the test data through the tuning procedures of $\beta$ values at the different mixed mode (I/II) loading.

• 한국전자파학회논문지
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• 제27권1호
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• pp.1-7
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• 2016

본 논문에서는 기계식 스위치를 이용한 1.5 GHz 대역 고출력 Cavity 기반 튜너블 필터를 설계하고 제작하였다. 불요파를 제거하기 위해 저역통과필터를 삽입하고, 출력을 추출하기 위해 Coupler를 내장하였으며, 고출력에 적합한 기계식 스위치를 사용하여 튜너블 필터의 시스템을 구성하였다. 저역통과필터는 4~12.75 GHz까지 40 dB 이상의 감쇄 특성을 얻었고, Coupler는 40 dB의 Coupling Value와 55 dB 이상의 Coupling Isolation을 얻었다. 제작된 기계식 스위치를 사용한 튜너블 필터 시스템은 1,495.9~1,510.9 MHz Bypass Mode에서 0.88 dB, 1,495.9~1,500.9 MHz Fil Mode에서 3.29 dB의 삽입손실 특성 및 중심주파수 1,498.4 MHz에서 132 W의 출력전력과 10 ms 이하의 스위칭 절환속도를 얻었다.

• Journal of electromagnetic engineering and science
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• 제8권3호
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• pp.96-99
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• 2008

This paper describes a $0.13-{\mu}m$ CMOS RF switch for $3{\sim}5$ GHz UWB band(mode 1). It can improve isolation characteristics between ports by using deep n-well RF devices while their source and body terminals are separated. From the measurement results, the proposed T/R switch is comparative to the on-wafer probing measurement results of the series-shunt T/R switches. When the proposed T/R switch operates as Tx mode, measured insertion loss from Tx to output port is less than 1.5 dB and isolation between Tx and Rx is more than 27 dB for $3{\sim}5$ GHz. Return loss for the Tx port is more than -10 dB and input P1dB is +10 dBm.

• 한국통신학회논문지
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• 제40권2호
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• pp.355-362
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• 2015

본 연구에서는 X-밴드 레이더에서 사용하는 9.385[GHz] 서큘레이터를 Y형 WR112 도파관속에 페라이트를 삽입하여 제작을 하였다. 페라이트 설계는 B/R(Below Resonance) 모드 방식을 사용하여, 페라이트 내부에서 전계 분포가 120도의 회전이 발생하는 조건과 페라이트의 내부의 직류 자계의 세기와 외부 자계의 세기를 계산하였다. 또한, 임피던스 정합을 포함하여 대역폭, 선택도, 삽입손실 등, 서큘레이터의 성능 향상을 위하여 두 개의 페라이트 사이에 같은 형태의 유전체를 삽입하였다. 최적의 페라이트 형태 및 유전체를 얻기 위하여 CST MWS를 이용하였다. 9.385[GHz]에서 시뮬레이션 결과는 정재파비 1.02, 분리도 -40dB, 삽입손실 0.2dB의 결과를 얻었고, 측정 결과는 정재파비 1.03, 분리도 -38dB, 삽입손실 1.2dB 이었다. 분리도, 정재파비는 시뮬레이션 결과와 잘 일치 하였지만, 삽입손실은 약 1dB 정도 크게 발생하였다.

• 대한치과보철학회지
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• 제47권1호
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• pp.1-11
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• 2009

연구목적: 심미 수복을 위한 색상 결정 방법으로는 색견본 (shade guide)과 치아를 눈으로 직접 비교하는 기존의 비색법과 최근 소개되기 시작한 색상 측정용 기기를 사용하는 방법이 있다. 비색법은 치과의사들과 기공사들 간의 색조 선택에 일관성이 결여되어 있는 등 많은 문제점이 지적되고 있지만 아직도 이러한 방법에 의한 색상 결정과 결정 색상에 대한 표현 방식이 임상 치의학에 적용되고 있다. 본 연구의 목적은 진료실과 기공소에서 사용하고 있는 색견본이 같은 값을 가지는지 ShadeEye - $NCC^{(R)}$ dental chroma meter (Shofu Inc., Kyoto, Japan)로 확인하고 또한 이 측정 기기의 두 가지 모드가 동일한 shade tab을 같은 값으로 인식하는지 확인하고자 하였다. 연구재료 및 방법: 첫 번째 실험에서는 모두 8개의 Vita Lumin Vacuum shade guide (Vident Inc., California, USA)를 모아 그 중 A1과 B1 shade tab을 각각 5회씩 색상 측정용 기기인 ShadeEye-$NCC^{(R)}$의 tooth mode와 porcelain mode로 나누어 색조 분석을 하였고 두 번째 실험에서는 치과 진료실과 기공소에서 실제 사용하고 있는 Vita Lumin Vacuum shade guide를 각각 12개씩 모아 역시 A1과 B1 shade tab을 색상 측정용 기기인 ShadeEye-$NCC^{(R)}$의 tooth mode와 porcelain mode로 나누어 색조 분석을 실시하였다. 결과: 첫 실험에서 8개의 색견본의 A1과 B1의 5회씩 측정에서 두 가지 mode에서 모두 채도 (shade), 명도 (value), 색상 (hue)에서 유의한 차이를 보였다(P<.05). 두 번째 실험에서는 진료실에서 사용하는 색견본과 기공소에서 사용하는 색견본 사이에는 통계적으로 유의한 차이를 보이지 않았으나, A1의 porcelain mode 에서 채도가 유의한 차이를 보여 (P<.05), 같은 shade tab이라 할지라도 채도에서 차이가 날 수 있음을 보였다. 결론: ShadeEye-$NCC^{(R)}$의 mode에 따라 동일한shade tab을 다른 값으로 인식하는 것으로 나타나 진료실과 기공소 간에 동일한 mode로 사용하는 것이 필요할 것으로 사료된다.

• 대한기계학회논문집A
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• 제25권2호
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• pp.289-295
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• 2001

The aim of this study is to investigate the ductile fracture behaviour under pure Mode II loading using A533B pressure vessel steel. Single punch shear(SPS) test was performed to obtain the J-R curve under pure Mode II loading which was compared with that of the Model I loading. Simulation using Rousellier Ductile Damage Theory(RDDT) was carried out with 4-node quadrilateral element(L(sub)c=0.25mm). For the crack advance, the failed element removal technique was adopted with a $\beta$ criterion. Through the $\beta$ value tuning-up procedures, $\beta$(sub)crit(sup)II was determined as 1.5 in contrast with $\beta$(sub)crit(sup)I=5.5. In conclusion, it was found that the J-R curve under Mode II loading was located at lower part than that under Mode I loading obtained from the previous study and that the $\beta$ values strongly depended on the loading type. In addition, the predicted result using RDDT showed a good agreement with the SPS experimental one under pure Mode II loading.

• 한국지열·수열에너지학회논문집
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• 제13권4호
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• pp.14-20
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• 2017

Refrigerant having high global warming potentials will be phased out due to environmental protection issues. R410A has been widely used in geothermal heat pump. However, it has a little high GWP by 2088 value. One of the recommended substitute for R410A refrigerant is R452B which having a GWP by 698 value. In this paper, the heating and cooling performance of the water-to-water geothermal heat pump unit with R452B was experimentally investigated. The performance of the heat pump adopting R452B was also compared with the system applying R410A. The heating and cooling capacity of R452B heat pump system showed a slightly lower values within 2% comparing with R410A system. However, the R452B system's coefficient of performance was enhanced by 5.2% and 13.7% at heating and cooling mode, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1049-1052
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• 2004

In general, contrary to the CRTs with impulsive emission, liquid crystal displays have motion artifacts such as blurring. ghost image, decrease of dynamic CR(contrast ratio), and stroboscopic motion due to hold type driving method. In this paper, to improve motion picture quality of LCDs. impulsive driving method of black data insertion was applied to the OCB mode which is well known for its fast LC response time and wide viewing angle properties. Subject evaluation was carried out with CRT, TN, SIPS(Super IPS). and impulsive driving OCB. Moving picture image quality near CRT was obtained in impulsive OCB driving mode

• 전자공학회논문지B
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• 제31B권10호
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• pp.21-31
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• 1994

This paper describes the multichannel combined R2MFC/DTMF/CCT reciver which provides a signaling service functions for call processing control in digital switching system. Using the TMS320C25 DSP chip, we have implemented multi-function receriver shich processes 8 channels of R2MFC, DTMF, and CCT signals simultaneously. In order to increase the channel multiplicity of the combined receiver. R2MFC and CCT receiver were employed by discrete Fourier transform(DFT) method using Goertzel algorithm, and DTMFreceiver was employ by infinite impulse reponse(IIR) filtering method using 4KHz subsampling technique. The combined receiver has 4 function modes for each channel such as R2MFC, DTMF, CCT, and Idle modes. The function mode of each channel may be selected at any time by single-chip micro-controller(.mu.C). Hence, the number of channels assigned for each function mode can be adjusted dynamically according to the signaling traffic variations. From the experimental test results using the test-bed, it has been proved that the combined receiver statisfies all receiver satisfies all receiver specifications, and provides good channel multiplicity and performance, Therefore, it may give a great improvement than existing receiver in cost, reliability, availability, and serviceability.