• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
• /
• pp.394-397
• /
• 2002

A design study of phase detectors for the 2.5 Gb/s CDR circuit using a standard 0.18-${\mu}{\textrm}{m}$ CMOS process has been performed. The targeted CDR is based on the phase-locked loop and thus it consists of a phase detector, a charge pump, a LPF, and a VCO. For high frequency operation of 2.5 Gb/s, phase detector and charge pump, which accurately compare phase errors to reduce clock jitter, are critical for designing a reliable CDR circuit. As a phase detector, the Hogge phase detector is selected but two transistors are added to improve the performance of the D-F/F. The charge pump was also designed to be placed indirectly input and output.

• 디지털산업정보학회논문지
• /
• 제8권3호
• /
• pp.185-198
• /
• 2012

This paper is to analyze consumer's acceptance phase of innovative IT product on the ground of dividing into product and application phase. In the acceptance phase of product determinants to consumer's satisfaction were analyzed and TAM(Technology Acceptance Model) were applied to the acceptance phase of application. It is analyzed that how well expected usefulness and perceived satisfaction to product have positively influence its performance and perceived satisfaction respectively in the acceptance phase of the product. In the acceptance phase of application, factors to consumers' satisfaction were analyzed to investigate its influence to the usefulness of application. Usefulness expectancy to the application and product were analyzed to figure out consumers'intention to use the product and effort and cost going into application use were also analyzed. Empirical study was implemented aimed at smart phone users. As a result, perceived usefulness expectancy to product have positively influence on perceived product performance and perceived product performance also affects perceived product satisfaction significantly. Although product satisfaction doesn't affect usefulness expectancy to the application, usefulness expectancy to the product and perceived product performance have positively influence on usefulness expectancy to the application significantly. And also usefulness expectancy to the both of application and product have positively influence on consumer's intention to use the product but consumer's effort and cost going into application doesn't affect to it, it's hold forth the possibility that consumer's effort affect consumer's intention to use the product.

• Journal of the Korean Physical Society
• /
• 제73권11호
• /
• pp.1794-1798
• /
• 2018

We have grown famatinite $Cu_3SbS_4$ films by using sulfurization of Cu/Sb stack film. Sulfurization at $500^{\circ}C$ produced famatinite $Cu_3SbS_4$ phase, while $400^{\circ}C$ and $450^{\circ}C$ sulfurization exhibited unreacted and mixed phases. The fabricated $Cu_3SbS_4$ film showed S-deficiency, and secondary phase of $Cu_{12}Sb_4S_{13}$. The secondary phase was confirmed by X-ray diffraction, Raman spectroscopy, photoluminescence and external quantum efficiency measurements. We have also fabricated solar cell in substrate type structure, ITO/ZnO/(Zn,Sn)O/$Cu_3SbS_4$/Mo/glass, where $Cu_3SbS_4$ was used as a absorber layer and (Zn,Sn)O was employed as a Cd-free buffer. Our best cell showed power conversion efficiency of 0.198%. Characterization results of $Cu_3SbS_4$ absorber indicates deep defect (due to S-deficiency) and low shunt resistance (due to $Cu_{12}Sb_4S_{13}$ phase). Thus in order to improve the cell efficiency, it is required to grow high quality $Cu_3SbS_4$ film with no S-deficiency and no secondary phase.

• 센서학회지
• /
• 제29권1호
• /
• pp.63-67
• /
• 2020

This study investigated the influence of various sintering pressures of ZnS nanoparticles prepared by hydrothermal synthesis performed at 220 ℃ for 20 h. The hydrothermally synthesized ZnS nanoparticles formed a cubic phase. The ZnS nanoparticles were sintered using a hot-press process at 850 ℃ for 2 h under pressures of 10, 20, 30, 40, 50, 60, and 70 MPa. The ZnS ceramics indicate the cubic phase is the major phase and the hexagonal phase is the minor phase. In the ZnS ceramics, as the sintering pressure increased, a decrement in the hexagonal phase was confirmed. When the sintering pressure equaled or exceeded 30 MPa, the transmittance and density improved with reductions in porosity and hexagonal phase. A sintering pressure of 60 MPa delivered the highest transmittance (69.7%).

• 한국정보통신학회논문지
• /
• 제26권8호
• /
• pp.1188-1195
• /
• 2022

6-단자 위상 상관기는 동위상 전력 분배기 한 개와 3-dB 90도 위상차 전력 분배기 세 개로 구성된 회로로 입력 신호의 위상을 판별하는 복조 회로에 주로 사용된다. 본 논문에서는 37.5-Ω 동축선 3개를 이용한 광대역 2:1 임피던스 변환 회로 구조의 동위상 전력 분배기와 Wireline 이용한 3-dB 90도 위상차 전력 분배기를 사용하여 광대역에서 동작하는 6-단자 위상 상관기를 제안하였다. 중심 주파수 1000MHz에서 제작된 제안된 광대역 6-단자 위상 상관기는 640~1270MHz 주파수 범위에서 동위상 전력 분배기 입력 신호에 대한 4개의 출력 단자로의 신호 전달 특성(S_i1)은 세기 -6.5±0.6dB와 위상 오차 ±3.4° 이내, 90도 위상차 전력 분배기 입력 신호에 대한 신호 전달 특성(S_i2)은 세기 -6.1±0.6dB와 위상 오차 ±6.2° 이내, 입력 반사계수(S₁₁ and S₂₂) -14dB 이하의 안정적인 값을 가졌다.

• 한국수산과학회지
• /
• 제32권6호
• /
• pp.791-797
• /
• 1999

Kluyveromyces fragilis (ATCC 36534)와 Candida utilis (ATCC 9950) 균주를 사료 첨가제와 rotifer 먹이로서 가치를 평가하기 위해 성장 단계별 및 세포벽의 화학처리에 따른 영양가를 분석하여 비교하였다. 조단백질 함량은 K. fragilis가 $48.2\~58.5\%$로 C. utilis의 $25.9\~43.4\%$보다 높은 경향을 보였고, 조지방 함량은 K. fragilis 및 C. utilis모두 $0.1\~1.6\%$로 매우 낮은 수준이었다. 조섬유의 함량은 두 효모에서 $0.6\~3.3\%$의 범위로 낮은 수준이었으며, protoplasted 효모의 경우는 다소 낮아지는 경향을 보였다. 효모종류에 따라 아미노산 조성이 다소 차이를 보였는데, Asp, Gly, Pro, Leu, Lys 및 Val은 K. fragilis가 C. utilis보다 그 함량이 높았으며, Glu 및 Arg은 C. utilis가 상대적으로 더 높은 경향을 보였다. 성장 단계별 아미노산 조성은 특별한 변화 경향이 없었으며, 세포 외벽을 처리한 protoplasted K. fragilis와 C. utilis의 Glu, Gly 및 Asg은 처리전보다 낮아지는 경향이었고, Leu, Phe 및 Val의 함량은 다소 높아진 것으로 나타났다. K. fragilis 및 C. utilis의 지방산은 대부분 $C_{18}$ 이하의 포화 또는 불포화산으로 구성되어 있었는데, 주로 $C_{16-18}$의 지방산들은 early log 또는 log phase에서 death phase로 갈수록, 그리고 protoplast에서 낮아지는 반면에 $C_{10-12}$와 같은 저급 지방산들은 증가하는 경향을 보였다. K. fragilis 및 C. utilis의 early log phase에서는 ATP 함량이 검출되지 않았지만, 그 후 단계 (log - death phase)에서 각각 증가하는 경향을 보였다 ADP 함량은 K. fragilis에서 early log phase 이후 단계부터 증가하였고, 세포막을 처리한 protoplast 상태에서는 높은 수준을 유지하였지만, C. utilis의 경우는 성장이 진행됨에 따라 감소하는 경향을 보였으며, protoplast 상태에서는 그 함량이 낮아지는 경향을 보였다. AMP 함량은 두 균주 모두 early log phase에서 낮은 수준이었지만, 그 후 단계에서는 높은 함량을 유지하였으며, protoplast 상태에는 검출되지 않았다 IMP 함량은 두 균주 모두 log phase에서 가장 높은 값을 보였으며, protoplast 상태에서는 낮은 값을 보였다. Inosine 함량은 K. fragilis의 성장이 진행됨에 따라 증가되었고, C. utilis에서는 K. fragilis보다 높은 경향이었으며, log phase에서 최대값을 보였다. 성장 단계별로 이들의 핵산관련물질의 총량은 두 균주 모두 early log phase에서 가장 낮은 값을 보였으며, 각 성장 단계별로 K. fragilis가 C. utilis보다 높은 값을 유지하였고. protoplast 상태에서는 C. utilis가 더 높은 값을 나타내었다.

• 열처리공학회지
• /
• 제12권1호
• /
• pp.21-30
• /
• 1999

The present study were investigated changes of precipitation behaviour of laves phase in ferrite single phase and ferrite-martensite dual phase and precipitation of laves phase under stress. Hardness changes in ferrite phase appeared two hardness peaks by precipitation of initial fine precipitator and laves phase in 3Mo-0.3Si and 3Mo-0.3Si-C specimens, respectively. Hardness changes in martensite phase of 3Mo-0.3Si-C specimen was lower in the initial stage of aging by carbide precipitation and after this, increased by re-hardening due to precipitation of laves phase. In the ferrite phase, laves phase was mainly precipitated, whereas in the martensite phase, carbide was preferentially formed during the initial stage of aging and with increasing aging time, laves phase and carbide were simultaneously precipitated by precipitation of laves phase at around carbide. In the ferrite-martensite interface, laves phase was mainly precipitated and carbide was mainly formed at boundary of lath martensite than grain boundary. Adding the stress in aging, fine precipitator of inital precipitation of laves phase precipitated in (100) of perpendicular to tensile direction and has grown to only followed<010>direction and also, volume fraction of laves phase increased. Consequently, the stress added was accelerated initial precipitation of laves phase.

• 센서학회지
• /
• 제28권4호
• /
• pp.256-261
• /
• 2019

In this study, mid-infrared transparent zinc sulfide (ZnS) ceramics were fabricated through hydrothermal synthesis with different molar ratios of S/Zn (S/Zn = 0.8, 1.0, 1.2, 1.4, and 1.6). The ZnS ceramics were sintered at a relatively low temperature of $850^{\circ}C$ to prevent the occurrence of the hexagonal phase featuring optical anisotropy. The phase composition, microstructure, and optical properties of the ZnS ceramics were subsequently investigated by employing X-ray diffraction, scanning electron microscopy, and Fouriertransform infrared spectroscopy. The results obtained indicate that the ZnS nanoparticles feature the cubic phase, without the hexagonal phase. Moreover, with increasing S, the crystallinity and particle size of the ZnS nanoparticles increased. The crystallinity and density of the ZnS ceramics improved when the molar ratio of S was higher than the molar ratio of Zn, thereby enhancing the transmittance. Furthermore, the ZnS ceramic with an S/Zn value of 1.2 was found to exhibit the highest transmittance of approximately 69% owing to the reduced occurrence of the hexagonal phase and a high density of 99.8%.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.179-180
• /
• 2010

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2009년도 춘계학술대회 논문집
• /
• pp.195-198
• /
• 2009

In this study, in order to get the forming limit of AHSS sheet in the negative minor strain region, the shapes of die corner and drawbead are redesigned by employing the Taguchi's design of experiment method and the FEM forming simulation. With the redesigned FLD tool, the forming limit tests of automotive multi-phase(Dual Phase and Complex Phase) steel sheets which induce the normal fractures on the blank are performed.