• 전기학회논문지P
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• 제57권4호
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• pp.431-436
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• 2008

We have extended an absolute evaluation method to obtain the ratio error and phase displacement of a current transformer (CT) up to primary current of 40,000 A by measuring four parameters of equivalent circuit in CT. The method was applied to CTs under test with the current ratios in the range of 5,000 A / 5 A - 40,000 A / 5 A. The ratio error and phase displacement of the CTs under test obtained in this study are consistent with those measured at the national institutes in Canada and Germany using the same CTs under test within an expanded uncertainty (k = 2) in the overall current ratios.

• International Journal of Fluid Machinery and Systems
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• 제2권1호
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• pp.80-91
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• 2009

In this study, a prediction theory for specific noise that is the overall characteristic of the fan has been proposed. This theory is based on total pressure prediction and broadband noise prediction. The specific noises of two forward curved fans with different number of blades were predicted. The flow around the impeller having 120 blades (MF120) was more biased at a certain positions than the impeller with 40 blades (MF40). An effective domain of the energy conversion of MF40 has extended overall than MF120. The total pressure was affected by the slip factor and pressure loss caused by the vortex flow. The suppression of a major pressure drop by the vortex flow and expansion of the effective domain for energy conversion contributed to an increase in the total pressure of MF40 at the design point. The position of maximum relative velocity was different for each fan. The relative velocity of MF120 was less than that of MF40 due to the deviation angle. The specific noise of MF120 was 2.7 dB less than that of MF40 due to the difference in internal flow. It has been quantitatively estimated that the deceleration in the relative velocity contributed to the improvement in the overall performance.

• 한국가금학회지
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• 제32권2호
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• pp.89-96
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• 2005

본 시험은 계분 및 돈분의 extrusion 처리가 산란계에 대한 산란성적 및 난질에 미치는 영향을 평가하기 위하여 실시하였다. 실험사료는 계분, 옥수수 및 타피오카를 $50\%,\;30\%$ 및 $20\%$로 혼합하여 extrusion 가공(BMERF)한 사료(실험 1)와 남은 음식물(FW), 돈분 및 옥수수를 $40\%,\;40\%$ 및 $20\%$로 혼합하여 extrusion 가공(SFERF)한 사료(실험 2)를 이용하였다. 실험처리는 실험 1에 4개 처리구(대조구, BMERF $10\%$, BMERF $20\%$ 및 BMERF $40\%$이며, 시험 2에 6개 처리구(대조구, FW $20\%$, W $40\%$, SFERF $10\%$, SFERF $20\%$, SFERF $40\%$)를 두었으며, 12주간 처리 당 4반복 반복당 30수를 공시하여 사양시험을 실시하였다. 남은 음식물, 계분, 돈분의 영양성분은 extrusion 가공에 의하여 단백질, 에너지 및 칼슘 함량이 유의하게(p<0.05)개선 되었다. 실험 1에서 사료섭취량은 대조구와 BMERF $10\%$구에 비하여 BMERF $20\%$ 및 $40\%$구가 높았으며(p<0.05), 산란율은 대조구와 BMERF $10\%$구 및 BMERF $20\%$구는 차이가 없었으나(p>0.05), BMERF $40\%$구는 유의적으로 낮았다(p<0.05). 사료요구율은 대조구와 BMERF $10\%$구는 차이(p>0.05)가 없었으나, BMERF $20\%$구 및 $40\%$구는 효율이 낮은 것으로 나타났다. BMERF 첨가는 난황색, 난백고 및 Haugh unit에 의하여 영향을 미치지 못하였다. 실험 2에서 사료섭취 량은 대조구, FW $20\%$구, SFERF $10\%$구 및 SFERF $20\%$구는 차이가 없었으나(p>0.05), FW $40\%$와 SFERF $40\%$구만이 유의적(p<0.05)으로 높았다. 산란율은 대조구와 SFERF $10\%$구와 SFERF $20\%$구는 차이(p>0.05)가 없었으나, FW $20\%$구, FW $40\%$구 및 SFERF $40\%$구는 유의적(p<0.05)으로 낮았다. 사료효율은 산란율과 비슷한 경향을 보였으며, 난중, 난황색, 난백고 및 Haugh unit는 처리 간 차이(p>0.05)가 없었다.

• 한국정보통신학회논문지
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• 제9권3호
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• pp.609-615
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• 2005

Sol-gel 법을 이용하여 La를 $10mo1\%$로 고정시킨 PLZT(10/y/z) 박막을 제작하여 Zr/Ti 조성비에 따른 전기적 특성을 조사하였다. Zr/Ti 조성비에서 Ti 함유량이 증가함에 따라, 10kHz에서 비유전률은 550에서 400으로 감소된 반면, 유전손실은 0.028에서 0.053로 증가되었으며, 170kV/cm에서 누설전류밀도는 $1.64\times10^{-6}$에서 $1.26\times10^{-7}\;A/cm^2$으로 감소되었다. PLZT 박막의 이력곡선을 $\pm170kV/cm$에서 측정한 결과, Zr/Ti 조성비가 40/60에서 0/100로 변화함에 따라 PLZT 박막의 잔류분극과 항전계는 6.62에서 $12.86{\mu}C/cm^2$, 32.15에서 56.45kV/cm로 각각 증가되었다. $\pm5V$의 사각펄스를 $10^9$회 인가하여 피로특성을 측정한 결과, PLZT(10/40/60) 박막의 잔류분극은 초기분극 값으로부터 $50\%$ 감소된 반면, PLZT(10/0/100) 박막은 $28\%$ 감소되었다. 또, $10^5$초의 retention 측정 결과에서 PLZT(10/0/100) 박막은 초기분극 값에서 오직 $10\%$만이 감소된 반면, PLZT(10/40/60) 박막은 $40\%$ 감소되었다.

• 복식
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• 제55권4호
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• pp.16-28
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• 2005

The purposes of this study were to understand the buying patterns of adult women according to impulse shopping, benefits sought, and selecting information sources. This subjects of this study were 509 adult women from the age 20's to the age of 40's. This data were analyzed by using factor analysis multi regression analysis, analysis of variance, Scheffe' test. The results of this study were outlined as follow: 1. Differences among ages (the 20's, the 30's, and the 40's) in impulse shopping were as follow: The 30's bought more cosmetics to change their mood compared to the 20's or the 40's, and the 20's and the 30's bought more cosmetics matching to their images compared to the 40's. 2. From the aspects of benefits sought, the 20's and the 30's were more seriously consider the fame of brands compared to the 40's, showing they were different from the 40's. 3. From the aspects of selecting information sources about cosmetics, the 20's were more actively utilizing both human information sources and non-human information sources compared to the 30's and the 40's.

• Human Ecology Research
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• 제58권2호
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• pp.201-214
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• 2020

This study researched the life experiences of 30-40's voluntary single women. Currently, a growing number of women in their 30s and 40s in South Korea are voluntarily choosing single life to achieve self-realization and focus on their lives. We want to take note of this phenomenon and take an in-depth the lives of voluntary single life beings they are experiencing by using hermeneutic phenomenological study method of Van Manen. The results of this study are as follows. First, 30-40s voluntary single women have experienced desire of self-realization through their single life. Second, they were satisfied with their lives based on the concept of having free choices, stable social support and they social-economic base. Third, they have experienced a low awareness of single life in society and many people. Last, they were preparing for their future lives for their physical health, finances, and role as parents' provider. This study provides a better understanding of the lives of 30-40s voluntary single women.

• 한국식품과학회지
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• 제27권1호
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• pp.56-62
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• 1995

This study was designed to investigate the changes in microflora and enzyme activities of traditional kochujang meju during fermentation for 60 days. The pH of meju decreased continously up to 40 days of aging and then increased slightly thereafter, while the change in titratable acidity showed the opposite trend to that of pH. The viable cell count of aerobic bacteria increared gradually for up to 40 days of fermentation and then decreased slightly thereafter, while that of molds and yeasts showed a rapid increase up to 40 days of fermentation and then leveled off. ${\alpha}-amylase$ activity increased slightly for up to 40 days of meju fermentation and then stabilized. On the other hand, ${\beta}-amylase$ and glucoamylase activities did not show a significant change for up to 20 days of fermentation and then increased rapidly at 40th day of fermentation. Acidic, neutral and alkaline protease activities increased sharply up to 40 days of aging and then decreased significently at 60th day of fermentation. These results suggest that meju fermented for 40 days had the highest quality in terms of the number of microflora and enzyme activity.

• BMB Reports
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• 제28권6호
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• pp.538-545
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• 1995

When DNA replication of simian virus 40 (SV40) is initiated on the replication origin, the regions containing the initiation sites of DNA primase, which participates in the transient RNA primer synthesis for formation of Okazaki fragments in the lagging strand, were chosen as the target sites of antisense RNA for studies of the inhibition of SV40 DNA replication. Four recombinant transcription vectors, pUC-PrI, pUC-PrII, pGEM-PrBS, and pGEM-PrSN, coding antisense RNA, were constructed. Four antisense RNAs (named as I, II, BS, and SN) having the size of 18, 19,58, and 123 nts, respectively, were made from the transcription vectors by in vitro transcription. And then, antisense RNA in the concentration of 2${\mu}m$ were added to COS cells transfected with pATSV-W which is a recombinant plasmid containing the SV40 origin of replication. The inhibitory extent of DNA replication was measured by DpnI resistance and was confirmed by measurement of transient RNA primer synthesis. The result shows that six combinations of antisense RNA (I, II, BS, SN, I+SN, and BS+SN) lead to the inhibition of SV40 DNA replication by up to 85%.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.654-657
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• 2002

This paper introduces the design and implementation of 40-㎓-band low noise amplifier (LNA) with ultra low gain flatness for wide-band wireless multimedia and satellite communication systems. The 40-㎓-band 4-stage LNA MMIC (Monolithic Microwave Integrated Circuit) demonstrates a small signal gain of more than 20 ㏈, an input return loss of 10.3 ㏈, and an output return loss of 16.3 ㏈ for 37$\square$42 ㎓. The gain flatness of the 40-㎓-band 4-stage LNA MMIC was 0.1 ㏈ for 37$\square$42 ㎓. The noise figure of the 40 ㎓-band LNA was simulated to be less than 2.7 dB for 37~42 ㎓. The chip size of the 4-stage LNA MMIC was 3.7${\times}$1.7 $\textrm{mm}^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.607-610
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• 2004

The Pb $(Zr_{0.52}Ti_{0.48})O_3/(Ba_{0.6}Sr_{0.4}TiO_3$ [PZT(52/48)/BST(60/40)] heterolayered thin films were fabricated on the Pt/Ti/$SiO_2$/Si by RF sputtering method. The structural properties of the PZT(52/48)/BST(60/40) heterolayered thin films were investigated with Ar/$O_2$ ratio condition. All the PZT(52/48)/BST(60/40) heterolayered thin films had shown the PZT(111), (200) and BST(200) Peaks of the tetragonal structure. Increasing the Ar/$O_2$ ratio, the average roughness was increased. The thickness ratio of the to the PZT and BST thin film was 1:2. In the case of the PZT(52/48)/BST(60/40) heterolayered thin films with Ar/$O_2$ ratio of 80/20, the average roughness was 3.4 [nm].