• 한국환경보건학회지
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• 제30권1호
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• pp.1-6
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• 2004

This study was performed to estimate the effects of washing of food wastes on temperature, pH, weight and volume reduction and salinity in aerobic composting of food wastes. Weight ratios of food wastes to water in washing were 1:0(Control), 1:1 (W-1), 1:2(W-2), 1:3(W-3) and :4(W-4), respectively. Ratios of food wastes to wood chips in reactor of Control, W-1, W-2, W-3 and W-4 were 5 kg:5 1, respectively. Reactors were operated for 24 days with 1 hour stirring by 1 rpm and 2 hours aeration per day. The increase in the ratio of food wastes to water used in washing resulted in the decrease of the highest reaction temperature and the elongation of the high temperature reaction period. The lowering of the ratio of food wastes to water used in washing resulted in faster pH increase and the steady state in the weight reduction rate and the volume reduction rate of composts. The final salinities of Control, W-1, W-2, W-3 and W-4 were 0.95%, 0.73％, 0.65%, 0.57％ and 0.41％, respectively.

• 한국분말재료학회지
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• 제1권1호
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• pp.52-59
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• 1994

Since the coefficient of thermal expansion (CTE) of matrix phase is larger about 4 times than that of W particle in tungsten heavy alloy, the thermal stresses due to the CTE difference between the two phases are induced in the alloy during heating and cooling processes. In the present study, a series of W heavy alloy containing various W particle volumes of 0 to 90% is made to investigate the residual stress taking place during cooling process. The CTE and residual stress of the series of alloy are measured by dilatometer and X-ray diffractometer. The residual stress of W particle is in compressive stress irrespective of W particle vol% and tends to increase with decreasing W particle vol% while that of the matrix phase is in tensile stress. The measured residual stress of W particle is about a third of calculated thermal stress. The influence of W particle vol% on the residual stress of W heavy alloy is discussed in terms of the deformation behaviors of W particle and matrix phase.

• 한국소음진동공학회논문집
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• 제16권2호
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• pp.124-131
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• 2006

This study introduces an environmental noise evaluation procedure for wind turbines(W/T) and the evaluation result of a 750 kW wind turbine(W/T) system. Test and evaluation are performed according to the international standard IEC 61400-11 on J48 W/T which is under operation in Daekwanryung W/T test site. With the meteorological data and W/T operational data, noise data are monitored and analysed. An integrated monitoring system is constructed in the test site and is utilized for the evaluation. From the measured noise data, acoustic power level, directivity and tonality of the W/T are estimated under the wind speeds required fly the International standard. The purpose of the study is to establish an W/T noise evaluating system satisfying the international standard and to obtain noise data for home made 750 kW W/T.

• 음성과학
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• 제13권4호
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• pp.7-21
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• 2006

The intent of the present study is to investigate the acoustic properties of Korean /w/ in various phonological contexts, compare them with those of English /w/, and attempt to explain why English /w/'s are perceived differently by Korean speakers depending on the phonological contexts. Experiments 1 and 2 present the acoustic measure of F2 of Korean /w/ in various linguistic positions and show that unlike English /w/, Korean /w/ shows quite a strong coarticulation with the following vowel. Based on these experiments, Experiment 3 investigates why English /w/ is adapted differently into Korean. Specifically, it discusses why English /wain/ is adapted as /wain/ whereas English /twin/ is adapted into Korean as $/t^{h_i}win/$ with an extra vowel. This study argues that the different perception of English /w/ by Korean and English speakers is due to the different F2 transitional pattern of /w/ in Korean and English in various phonological contexts. It also argues that the F2 transitional pattern is an important factor in the perception of /w/.

• 한국분말재료학회지
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• 제6권1호
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• pp.36-41
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• 1999

The present work has attempted to investigate the dependence of Cu infiltration kinetics on in-situ structure modification of W powder skeleton in W-Cu system. In-situ structure modification of W skeleton by addition of 0.3wt%Ni-P eutectic alloy was designed to proceed during heat-up of the W compact for Cu infiltration process. It was found that the Ni-P added W skeleton underwent remarkable stucture change only during heating-up. its structure was composed of large necks of W particles above 0.5 in the ratio of neck to particle size and smooth pore channels. The infiltration experiment showed that the infiltration kinetics for the W-Ni-P followed well the linear relationship of h vs. $t^{1/2}$ the rate constant K of which was in good agreement with the theoretical value. On the other hand, in case of the pure W skeleton a lower K value by 20% than the theoretical one was obatined. Such discrepancy is discussed in terms of skeleton structure induced infiltration mechanics.

• Journal of Ecology and Environment
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• 제29권5호
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• pp.485-488
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• 2006

Allometric equations for biomass measurement of the shrub species, Lindera obtusiloba, were developed. The allometric equations between $(BD)^2H$ and dry weight of leaves ($W_I$), stems and branches ($W_{sb}$), roots ($W_r$) and total weight ($W_t$) of the Lindera obtusiloba were as follows: $W_I=0.7318\;(BD^2H)^{0.6108},\;W_{sb}=0.6067(BD^2H)^{0.8355},\;W_r=0.4524(BD^2H)^{0.7608},\;W_t=1.672 (BD^2H)^{0.7664}$. The $R^2s$ between $(BD)^2H\;and\;W_I,\;W_{sb},\;W_r\;and\;W_t$ of the Lindera obtusiloba were 0.9251, 0.9571, 0.9353 and 0.9546, respectively. Root weight of this Lindera obtusiloba was about 38% of the aboveground biomass.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.308-311
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• 2006

A vibration monitoring is performed on a 1kW class stand alone wind turbine(W/T). When a W/T model is developed, general performance under various wind condition should be verified to introduce the product in the market. Especially, vibration characteristics within operating speed range are very important in the aspect of structural stability as well as generator's electrical efficiency. This paper examines the vibration performance of a home made 1kW W/T Various data of the W/T model are acquired in real time using a remote vibration monitoring system installed in Daekwanryung test site. Vibration stability of the W/T structure is diagnosed based upon the data and the result is used to estimate the applicability of the W/T model.

• Journal of applied mathematics & informatics
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• 제8권1호
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• pp.225-229
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• 2001

In this paper, we obtain a topology T/sub w/ on X. Using this topology, we obtain a chracterization of w-convergence.

• 한국수정란이식학회지
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• 제21권2호
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• pp.121-128
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• 2006

본 연구는 고품질의 돼지 체외 수정란을 생산하기 위하여 체외 성숙 배지에 첨가하는 polyvinylpyrrolidone(PVP)의 분자량, 첨가 농도 및 시간(실험 1)과 체외 성숙 수정 배양 단계에서 PVP의 첨가(실험 2)가 배 발생과 세포수에 미치는 효과를 검토하였다. 돼지 미성숙 난자의 체외 성숙은 NCSU 23 용액, 체외 수정은 mTBM 용액, 체외 배양은 PZM 3 용액을 이용하였다. 체외 성숙용 배지에서 PVP의 분자량, 농도 및 첨가 시간에 따른 수정율과 배반포 발달율은 차이가 없었다. 그러나 배반포의 부화율은 분자량 40,000(30.1%), 0.5%(28.6%) 및 $0{\sim}44$시간(37.5%) 첨가군이 다른 시험군에 비하여 유의하게 높았다(p<0.05). 분자량 40,000 0.5% PVP를 체외성숙, 수정 및 배양 배지에 각각 첨가(W) 또는 미첨가(W/O)한 결과, 수정율은 체외성숙 수정 배양에서 W-W/O-W 군이 69.3%, 배반포 발달율과 부화율은 W-W/O-W 및 W-W/O-W/O 군이 각각 12.6과 30.0% 및 14.0과 37.5%로서 다른 군에 비하여 유의하게 높았다(p<0.05). 총 세포 수와 Trophoblast 수는 처리군 간에 유사한 경향이었으나, Inner cell mass 수는 W/O-W/O-W 군이 평균 7.4개로서 가장 높았다 (p<0.05).

• 한국미생물·생명공학회지
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• 제39권1호
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• pp.70-76
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• 2011

Weissella 속 유산균 검출의 차이를 이용한 한국산 및 중국산 김치 판별의 가능성 검토를 위하여 Weissella 속 9종 균주의 PCR 검출법을 개발하였다. 종(species) 수준에서의 Weissella 속 균주의 특이적 PCR 검출을 위한 primer는 recN 유전자의 염기서열을 이용하여 선정하였으며, 김치로부터 W. cibaria, W. confusa, W. koreensis, W. soli를 모두 검출하기 위해서는 20 ng template DNA가 필요한 것으로 나타났다. 한국산 김치시료로부터는 W. cibaria, W. confusa, W. koreensis가 높은 빈도로 검출되었지만, W. soli는 검출되지 않았다. 한편 중국산 김치시료로부터는 이들 4종의 Weissella 속 균주들이 모두 검출되었다. 본 연구자들이 개발한 W. soli 특이적 PCR 검출은 현시점에서 중국산 김치의 원산지 판별법으로 적용되기에는 한계점을 가지고 있지만, 미생물 군집의 차이를 이용한 새로운 과학적 검증법이 제시되어 그 가능성이 검토되었다는 점에서 의의를 가지고 있다.