• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 하계종합학술대회 논문집
• /
• pp.191-194
• /
• 1999

The balanced amplifier is a practical amplifier to, implement a broadband amplifier that has flat gain and good input and output VSWR. Three-stage amplifier design procedure usually divided into three partition satisfying the following requirements : low noise figure, high gain and high power output. FHX35LG HEMT device is used in the design can be obtained low noise figure at the first-stage, MGA82563 MMIC device is used in the design can be maintained high gain at the second-stage, and AHI MMIC device is used in the design can be required high power output at the third-stage. The results of three-stage balanced amplifier show that power gain is about 40㏈, noise figure is less than 1.2㏈ at operating frequency.

• 전자공학회논문지A
• /
• 제32A권3호
• /
• pp.110-117
• /
• 1995

New formulas for the minimum noise figure and the optimum source impedance of microwave FETs are derived using the noise equivalent circuits obtained from the steady-state Nyquist theorem for multi-terminal semiconductor devices. The derived formulas manifest the relationships between the noise sources and the physical parameters of a noise equivalent circuit. Furthermore the formulas can explain the effect of gate leakage current on the minimum noise figure and the optimum source impedance. comparisons with the published experimental data confirm the validity and usability of our formula.

• 한국분말재료학회지
• /
• 제7권1호
• /
• pp.6-11
• /
• 2000

Two kinds of Bi2Te3 powders, pure Bi2Te3/2vol.%ZrO2, have been prepared by a mechanical grinding process process. Effect of mixing of the powders on thermoelectric of the sintered body has been investigated by measuring Seebeck Coeffcient, specific electric resistivity and thermal conductivity. With an increase in the weight fraction of the Bi2Te3/2vol.%ZrO2 powder from 0 to 40wt.%. Especially, the figure of merit of the mixedBi2Te3 sintered body increases and thereafter dedreases above 40wt.%. Especially. the figure of merit of the mixed Bi2Te3 sintered bodies with mixing of Bi2Te3/2vol.%ZrO2 powder increased about 1.3time in comparison with the value of the specimen before mixing. Mixing of two kinds of Bi2Te3 powders which have different theramal and electric propertries with each other seemed to be useful methob to increase the figure of merit of Bi2Te3 sintered body.

• 대한가정학회지
• /
• 제30권3호
• /
• pp.56-62
• /
• 1992

The purpose of this study was to characterize the somatotype of children and to provide fundamental data for the construction of the dress figure. The subjects for anthropometric measurements were 384 elementary school children aged from 6 to 7 living in Seoul and Pucheon. The data were analyzed statistically according to SPSS/PC ＋ version 3.1. Through the factor analysis, six factors were obtained. The six factors represented the body girth and weight, the height and sleeve length, the trunk length, the shoulder size, the body curvature, and the posture of upper torso, respectively. The subjects were classified into six clusters. Among the six clusters, four clusters covered about 95.9% of the whole subjects were determined as the sources of fundamental data for the children's dress figure.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
• /
• pp.312-313
• /
• 2004

The optical gain saturation and noise figure characteristics of 1550nm traveling-wave semiconductor optical amplifiers are analyzed experimentally and theoretically. The result shows that there is an optimum active layer thickness for high saturation output power and low noise figure.

• Journal of Magnetics
• /
• 제2권2호
• /
• pp.46-49
• /
• 1997

This paper reports the first success in enhancement of the magneto-optic figure of merit of garnet films in blue wavelengths. The maximum of the absolute value of the Faraday rotation angle observed at about 500 nm for the films with no La substitution shifted toward shorter wavelength as La content increased, that leads the increase of the absolute value of the Faraday rotation angle in the wavelengths shorter than about 480 nm. The optical absorption coefficient at the wavelengths shorter than 500 nm decreased as La content increased. As a result the magneto-optic figure of merit increased in the wavelengths shorter than 470 nm as La content increased and was about two times larger for the film with La content of 0.6 in formular unit compared to that of the film without La substitution. This might be attributed to the shift of the centers of the charge transfer and crystal field transitions by La substitution.

• ETRI Journal
• /
• 제24권3호
• /
• pp.190-196
• /
• 2002

This paper presents millimeter wave monolithic microwave integrated circuit (MMIC) low noise amplifiers using a $0.15{\mu}m$ commercial pHEMT process. After carefully investigating design considerations for millimeter-wave applications, with emphasis on the active device model and electomagnetic (EM) simulation, we designed two single-ended low noise amplifiers, one for Q-band and one for V-band. The Q-band two stage amplifier showed an average noise figure of 2.2 dB with an 18.3 dB average gain at 44 GHz. The V-band two stage amplifier showed an average noise figure of 2.9 dB with a 14.7 dB average gain at 65 GHz. Our design technique and model demonstrates good agreement between measured and predicted results. Compared with the published data, this work also presents state-of-the-art performance in terms of the gain and noise figure.

• 전기학회논문지
• /
• 제57권12호
• /
• pp.2269-2275
• /
• 2008

This paper examined the simulation results after applying not only spiral inductor's 3D EM simulation but also de-embedding technique to reduce the pad's RF effects. When calculating standard deviation with measurement results not only the gain at 0.5GHz${\sim}$4GHz but also noise figure at 1.8GHz${\sim}$4GHz, the simulation results includes de-embedded inductor' model improved gain deviation by 0.171 and noise figure deviation by 0.151 than the results from simulation with foundry inductor equivalent circuit models.

• 복식문화연구
• /
• 제22권6호
• /
• pp.965-978
• /
• 2014

To determine the parameters to be considered when designing lower-body apparel, we analyzed the lower-body figures of adult women in their early 20s from Shanghai, China, using 3-dimensional whole body scanner. Thirty-nine lower-body-related measurements were used to analyze the figures of 210 Chinese women. Obesity and height of the lower body, length from waist to crotch, shape of abdomen, and leg bone length were analyzed. Factor analysis was performed and the results were classified into three clusters. The first cluster describes the obesity of the lower body, the second denotes small hip measurement, and the third describes slim and long legs. This is the first study to quantify figure analysis of the lower body of Chinese women using 3-dimensional body measurements. The findings of this study will provide concrete information regarding crotch width, crotch length, inseam, outseam, waist slope, etc., for designing trouser patterns for Chinese adult women.

• The Korean Journal of Ecology
• /
• 제15권3호
• /
• pp.221-229
• /
• 1992

This experiment was carried out to investigate the effect of liming on life form and ecological behaviour of stand in low productive grassland with acidified solil at dairy fram in yesan, chungnam province. The inferior plant community of low productive grassland was improved to the most desirable pasture association with herbage of 84% by liming. the life forms of association in low productive grassland were composed of hemicryptophytes of 49.4%, therophytes of 48.2%, geophytes of 2.2% and chamaephytes of 0.2% but by liming their life forms of hemicryptophytes increased greatly by 32.6%, on the other hand geophytes were much more decreased by 33.4%. The ecological behaviour of moisture figure and nitrogen figure were slightly increased and soil reaction figure was gradually decreased in low productive grassland by liming.