• 한국세라믹학회지
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• 제24권3호
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• pp.270-276
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• 1987

The microstructure and dielectric properties of a SrTiO3-based GBL (Grain Boundary Layer) capacitor were investigated. The 0.6 mol% Nb2O5 doped SrTiO3 was sintered for 3 hr at 1450$^{\circ}C$ in mixed gas(N2/H2) atmosphere. The Nb2O5 promoted the grain growth of the SrTiO3 ceramics was decreased with the amount of Nb2O5. The oxide mixture(PbO, Bi2O3, B2O3) were painted on the reduced specimen and fired at 1000$^{\circ}C$ to 1100$^{\circ}C$ in air. The penetrated oxide mixture into specimen were located in grain boundaries. A SrTiO3-based GBL capacitor had the apparent permittivity of about 3.0${\times}$104, the dielectric loss of 0.01-0.02, and insulating resistance of 108-109$\Omega$.cm. The capacitor had the stable temperature coefficient of capacitance and exhibited dielectric dispersion over 107 Hz. The capacitance-voltage measurements indicated that the grain boundary was composed of the continuous insulating layers.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.110-115
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• 1998

Through the ISODATA method, the micro-landform of Julpo-Bay tidal flat was classified into mudflat, mixedflat, and sandflat using Landsat TM image. Each showed an apparent differences in its topographical characteristics and grain size composition. For example, mudflats are formed with flat faces and tidal channel of dissected gully. Its characteristics of grain size analysis that the grains have less than mean grain size 4 phi. Its sorting is bad (higher than 1 S.D.), and it showed strongly positive skewness. But sandflat is topographically flat without tidal channel. It has developed with ripple marks. According to the grain size analysis of deposits, the soil is coarse size with 90% of sand and its sorting is well(lower than 1 S.D.) Also, it showed strongly negative skewness. Mixed flat is in between mudflat and sandflat in its characteristics.

• Journal of Welding and Joining
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• 제21권2호
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• pp.82-88
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• 2003

The bonding phenomenon and mechanism in the transient liquid phase bonding(TLP Bonding) of directionally solidified Ni base superalloy, GTD-111 was investigated. At the bonding temperature of 1403K, liquid insert metal was eliminated by isothermal solidification which was controlled by the diffusion of B and Si into the base metal and solids in the bonded interlayer grew epitaxially from mating base metal inward the insert metal. The number of grain boundaries formed at the bonded interlayer was corresponded with those of base metal. The liquation of grain boundary and dendrite boundary occurred at 1433K. At the bonding temperature of 1453K which is higher than liquation temperature of grain boundary, liquids of the Insert metal were connected with liquated grain boundaries and compositions in each region mixed mutually. In Joints held for various time at 1453t phases formed at liquated grain boundary far from the interface were similar to those of bonded interlayer. With prolonged holding time, liquid phases decreased gradually and liquids of continuous band shape divided many island shape. But liquid phases did not disappeared after holding for 7.2ks at 1453k. Isothermal solidification process at the bonding temperature which is higher than the liquation temperature of the grain boundary was controlled by diffusion of Ti to be result in liquation than B or Si. in insert metal. (Received January 15, 2003)

• 한국재료학회지
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• 제13권6호
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• pp.352-359
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• 2003

In order to control the grain size, the spark plasma sintering technique is applied for the manufacturing of Cu-26.7Al-4.05AI(wt.%) shape memory alloy with pure Cu, Zn, and Al element powders. The sintering processes were carried out under different atmospheres. The sintered bodies were denser under Ar or Ar＋4%$H_2$gas atmosphere than under vacuum. With use of small-sized powders, a very small average grain size of 2∼3 $\mu\textrm{m}$ was obtained, but the single phase was not formed. With the large-sized powders the single austenitic phase was observed with the average grain size of $70∼72\mu\textrm{m}$. When the different size of raw powders was mixed, it is confirmed that the average grain size of the manufactured alloys was 15 $\mu\textrm{m}$ with single austenitic phase, but the distribution of grain size was not uniform.

• 한국재료학회지
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• 제23권11호
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• pp.625-630
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• 2013

In this study, intermediate-mixed powders were prepared by loading zirconia powders initially in a ball-mill jar and loading alumina powders afterward; the initial-mixed powders were produced by loading zirconia and alumina powders together in the ball-mill jar. The effect of such differences in mixing method on the mechanical properties was investigated. In intermediate-mixed powders, the volume fraction of large particles slightly increased and, simultaneously, zirconia particles formed agglomerates that, due to early ball-mill loading of the zirconia powders only, were more dispersed than were the initial-mixed powders. For the intermediate-mixed powders, zirconia agglomerates were destroyed more quickly than were initial-mixed powders, so the number of dispersed zirconia particles rose and the inhibitory effect of densification due to the addition of a second phase was more obvious. In the microstructure of intermediate-mixed powders, zirconia grains were homogeneously dispersed and grain growth by coalescence was found to occur with increasing sintering temperature. For the initial-mixed powders, large zirconia grains formed by localized early-densification on the inside contacts of some zirconia agglomerates were observed in the early stages of sintering. The intermediate-mixed powders had slightly lower hardness values as a whole but higher fracture toughness compared to that of the initial-mixed powders.

• Asian-Australasian Journal of Animal Sciences
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• 제16권5호
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• pp.672-676
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• 2003

Effect of a surfactant Tween 80 on the bacterial growth in the rumen was examined on the in vitro pure cultures of Streptococcus bovis, Selenomonas ruminantium, Butyrivibrio fibrisolvens, Prevotella ruminicola, Megasphaera elsidenni, Fibrobacta succinogenes, Ruminanococcus albus and Ruminococcus flavefaciens. Dry matter degradability (DMD), concentrations and compositions of volatile fatty acids (VFA), and the most probable number (MPN) of cellulolytic bacteria and total number of bacteria in the presence of Tween 80 were also examined on the in vitro rumen mixed culture either with barley grain or orchardgrass hay. The growth of S. bovis, S. ruminantium, B. fibrisolvens, P. ruminicola, M. elsidenni and F. succinogenes were significantly higher (p<0.05) at over 0.05% concentrations of Tween 80 than those of the control cultures, while was not changed with R. albus and R. flavefaciens. With rumen mixed culture the DMD of barley grain and orchardgrass hay was significantly higher (p<0.05) at a 0.2% concentration of Tween 80 than the control, being reflected in the significantly higher (p<0.05) VFA production (mmol $g^{-1}$DDM) with orchardgrass hay. The higher (p<0.05) ratio of propionate to acetate at a 0.2% concentration of Tween 80 was also observed with orchardgrass hay, showing a similar trend with barley grain. No changes in the total bacterial number and MPN of cellulolytic bacteria were observed.

• 대한지역사회영양학회지
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• 제16권3호
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• pp.353-363
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• 2011

The objective of the current study was to examine associations of whole grain consumption with socio-demographic (i.e.: sex, age, household income, education, marriage status) and certain eating behavior factors (i.e.: dish source, eating place, meal type) among a generally healthy Korean population. Using twenty-four hour recall data from the 2007-2008 National Health and Nutrition Examination Surveys, whole grain intake (g/day) was calculated for a total of 8,836 generally healthy Koreans aged 6 years and higher. The study subjects had very low whole grain intake. Specifically approximately 60% of the subjects reported no whole grain consumption on the survey day, and mean daily intake ranged from 8.0 g to 15.1 g in different gender and age groups. Living with a spouse was found to be a positive environment factor for whole grain consumption, especially among men. As household income levels increased, whole grain consumption status also improved. The proportion of non-consumer was lowest in a 6-19 year group, and mean intake amount was highest in middle-aged adults. Major dish sources for whole grain consumption included boiled rice with mixed grains, corn, boiled rice with brown rice, cereal products, and other types of boiled rice. It was found that whole grain consumption was highly affected by eating places rather than meal types. The best contributing eating place was home in each age and gender group. The study findings may be useful in planning nutrition education strategy and formulating dietary behavior guidelines for whole grain consumption improvement.

• 한국작물학회지
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• 제67권2호
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• pp.85-94
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• 2022

혼반용 유색 찰 현미 생산을 위해 품종의 혼합 재배 기술을 이용하면 노동력 절감과 더불어 수량증대로 인한 농가소득 향상에 도움이 될 것으로 기대 된다. 유색미의 경우 현미 색이나 품종별로 항산화 및 혈중 콜레스테롤 저하 등의 다양한 기능성 성분을 함유하고 있으며 본 연구에서는 혼반용으로 적합한 유색미 품종의 선발과 재배기술의 생력화를 위하여 유색미 혼합재배기술에 대한 연구를 수행 하였다. 유색미에 함유되어 있는 페놀화합물의 정성 및 정량분석 결과 황갈색 계열의 품종 및 자원은 Ferulic acid와 Salicylic acid 함량이 높았으며, 적미 계열의 품종 및 자원은 Ferulic acid, Gentisic acid, Catechin 함량이 높았다. 흑미 계열의 경우 Ferulic acid, Caffeic acid, Cinnamic acid 함량이 높았고 적미, 녹미 등 다른 계열의 유색미에 비해 Quercetin 함량이 높은 경향이었다. 녹색계열의 녹원찰벼의 경우 Ferulic acid, Coumaric acid 함량이 높았으며 특히 Coumaric acid 함량이 다른 계열의 유색미에 비해 높았다. 블랜딩 유색미 생산을 위해 품종을 혼합하여 재배할 경우 주당수수, 등숙율 증가로 단일품종으로 재배하는 것보다 수량이 18~20% 증수 되었으며, 혼합재배 유형 중 1품종 1열 재배에서는 녹원찰, 종자혼합 재배에서는 청풍흑향찰, 한강찰과 아랑향찰은 혼합재배 유형 모두에서 생산성이 높아지는 경향이었다.

• Journal of Animal Science and Technology
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• 제44권1호
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• pp.75-86
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• 2002

반추동물에서 적당한 조사료의 공급은 젖소의 정상적인 반추 기능을 위해서 반드시 필요하다. 본 연구는 사료 작물 종류별, 볏집 및 곡류의 가공 상태를 달리하여 제조한 TMFF에 대하여 일반 성분, RFV 및 면양의 반추위 성상 변화를 조사하기 위하여 실시하였다. 청예 작물인 옥수수, 목초, 호밀, 유채, 알팔파와 귀리를 주구로 하고 곡류 가공 수준을 무가공 (대조구), 거칠게 분쇄 (7～14mm mesh 이상), 일반 분쇄 (7mm 이하)를 세구로 하여 조제한 각각의 TMFF에 대한 일반 성분을 조사하였다. 또한 Fistula가 부착된 면양 8두를 이용한 반추위 성상과 기호성에 미치는 영향을 조사하였다. 유채 TMFF는 상대적 사료가 (RFV)와 일당 사료 섭취량, A/P 비율에 있어서 다른 처리구보다 높은 경향을 나타내었다. 옥수수 TMFF를 급여한 면양의 반추위 VFA 함량은 90.9 mmol%로서 다른 처리구 보다 높았으며, 또한 사료의 pH도 3.82로서 가장 낮은 경향을 보였다. 그러나 TMFF에 있어서 휘발성 지방산 각각에 대한 차이는 찾을 수 없었다. 결론적으로 곡류 가공 방법에 따른 효과는 나타나지 않았지만 상대적 사료가와 기호성, 건물 손실율만을 고려하여 우수성을 판단할 때 유채, 옥수수, 알팔파, 목초, 귀리, 호밀 TMFF의 순서로 나타났다.

• 한국지반신소재학회논문집
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• 제14권2호
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• pp.89-94
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• 2015

본 연구에서는 제주도 내에서 발생되는 현무암 석분슬러지를 차수용 재료로 재활용하기 위하여 최적의 석분슬러지 혼합비를 가진 혼합토를 선정하고자 한다. 토질시험결과에 따르면 현무암 석분슬러지의 입경은 대부분 0.1mm 이하이고, 토질의 분류기준인 통일분류법(USCS)을 적용하면 ML 및 CL에 해당한다. 그리고 현장토의 입경은 0.1-10mm 사이에 존재하고, 통일분류법(USCS)을 적용하여 분류하면 SW에 해당한다. 최적의 석분슬러지 혼합비를 가진 혼합토를 선정하기 위하여 다양한 석분슬러지 혼합비를 가진 혼합토를 대상으로 최적 다짐조건 및 현장조건을 고려하여 투수시험을 수행하였다. 투수시험결과 석분슬러지 혼합비가 증가함에 따라 혼합토의 투수계수는 감소하는 경향을 보이며, 석분슬러지의 혼합비가 60%인 경우 가장 낮은 투수계수를 갖는다. 따라서 현무암 석분슬러지를 차수용 재료로 재활용하기 위한 석분슬러지 혼합토의 최적 혼합비는 60%임을 알 수 있다.