• 한국식품조리과학회지
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• 제9권3호
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• pp.181-186
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• 1993

Potato and carrot are the main sourses of vitamin C and vitamin A each. As a folk ramedy, potato-carrot mixtures have been used to cure a stomach ulcer in Korea. To investigate the effects of carrot juice on the browning of potato juice, we examined the brewing in various ratio of two juices. We also investigated the role of potato juice in the carotene oxidation of carrot juice. Delta "L" values of potato juice were abruptly decreased after 5 min. reaction and they were very different from the juice mixture of potato and carrot. Those containing higher ratio of potato were decreased greatly. In blanching treatment to eliminate the effect of the enzymes in potato and carrot, delta "L" values of cooked potato were decreased a little but those of cooked carrot were decreased greatly. To investigate the fact that the inhibitory effect of carrot juice in potato browning was due to the dilution of polyphenolics of potato juices by carrot juice mixing, we added H20 equivalent to carrot water content to potato juice. The diluted sample showed less decreasing pattern than nondiluted sample. We also added appropriate amount of ${\beta}$-carotene to the same samples. Delta "L" values of with added B-carotene were more slowly decreased than those of without added B-carotene.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.663-678
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• 2018

Refractive index and speeds of sound for the binary mixture of isomer of butanol (1) + cyclohexane, benzene and toluene (2) were measured at 308.15 K. The measured data were used to calculate deviation in refractive index ${\Delta}n$, ultrasonic speed ${\Delta}u$, isentropic compressibility $K_s^E$, available volume $V_a$, excess intermolecular free length $L_f$ and molecular association $M_A$. All the derived properties were correlated with polynomial equation. Ultrasonic speed data were predicted using various empirical correlations like Nomoto, van Dael, impedance dependence and theoretically with Schaaff's collision factor theory (CFT). Jacobson free length theory (FLT) was used to calculate $L_f$. The measured refractive index was also correlated with various mixing rules. The deviation in refractive index Δn and ultrasonic speed ${\Delta}u$ was used to determine the intermolecular interactions.

• Elastomers and Composites
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• 제45권1호
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• pp.44-50
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• 2010

기계적 혼련법으로 butadiene rubber(BR)과 대표적인 결정성고무인 chloroprene rubber(CR) 블렌드 혼련물을 제조하여, 이들의 가교 거동, 기계적 성질, 내오존성 및 동적 기계적 성질 등을 검토하였다. 내오존시험에 있어서 50 wt% CR 고무의 첨가에 의하여 크게 개선됨을 확인할 수 있었다. Rheovibron에 의한 동적 계적 특성 측정의 결과로부터 BR/CR 블렌드는 두 개의 전이를 보였으며 $tan{\delta}$ 피이크의 위치는 CR 고무의 함량이 증가함에 따라 고온 쪽으로 이동함을 확인할 수 있었다. 한편 CR 고무량이 증가할수록 최적 가황시간이 증가하는 경향을 보였다.

• Journal of the korean society of oceanography
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• 제33권1-2호
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• pp.1-7
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• 1998

In the western Weddell Sea, winter mixed layer is characterized by near-freezing temperature and higher salinity due to brine injection through sea-ice formation. This layer becomes Winter Water being capped by warmer and less saline Antarctic Surface Water during the sea-ice melt-ing season. In this study, Winter Water was preliminarily identified by the oxygen isotopic com-positions. The ${\delta}^{18}$O values of Winter Water show the progressively increasing trend from south to north in the study area. It presumably reflects the enhanced mixing with Antarctic Surface Water due to the extent of influence by low S'"0 value of sea-ice/glacier meltwater. Correlations between salinity and 6'"0 values of seawater can be used to more generally characterize Winter Water with a view to identification. However, the prediction on the degree of mixing from these relationships needs more detailed isotope data, although this study allows the oxygen isotopic composition of seawater as a tracer to identify the water mass.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.525-530
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• 2000

The effects of vortex generators, in the form of small tabs projecting into the flow at the axisymmetric supersonic nozzle exit and triangular thin tapes attached on the inner surface at the nozzle exit, on the characterixtics of supersonic mixing enhancements are experimentally investigated. Delta-shaped tabs as small as 1% of the nozzle exit area produce strong counter-rotating vortices, and is found to produce significant effects on the jet flowfield downstream of the nozzle. The effects is larger on the under-expanded cases than over- and perfect-expanded cases. Nozzle inner surface roughness also can do a role of centerline pressure decay for highly under-expanded jet cases. The effects of the angle of tabs with respect to flow direction are also investigated.

• Elastomers and Composites
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• 제30권2호
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• pp.112-121
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• 1995

The physical properties of rubber compounds containing silica and siliane coupling agent in order to replace the carbon black and prepare for environmental regulation showed improved dynamic properties(rebound, heat build-up, $60^{\circ}C\;tan\;{\delta}$), but the abrasion resistance did not improve compared with the compounds containing carbon black. Also, curing retardation because of coherent structure of silica improved by the addition of DEG, but the mixing step change of activators did not so much improve the static and dynamic properties of the compounds containing high synthetic rubber, the status of mixing and dispersion showed that the compounds containing carbon black was much better than the compounds containing silica by TEM investigation.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권1호
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• pp.1-12
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• 2017

Nitrate ($NO_3^-$), a common surface water and groundwater pollutant, poses a serious environmental problem in regions with intensive agricultural activities and dense population. It is thus important to identify the source of nitrate contamination to better manage water quality. Due to the distinct isotope compositions of nitrate among different origins, the dual isotope analysis (${\delta}^{15}N$ and ${\delta}^{18}O$) of nitrate has been widely applied to track contamination sources. This paper provided the underlying backgrounds in the isotope analysis of nitrate, which included typical ranges of ${\delta}^{15}N$ and ${\delta}^{18}O$ from various nitrate sources, isotope fractionation, the analytical methods used to concentrate nitrate from samples, and the potential limitations of the dual isotope analysis along with the resolutions. To enhance the applicability of the dual isotope analysis as well as increase the ability to interpret field data, this paper also introduced several case studies. Furthermore, other environmental tracers including ${\delta}^{11}B$ and $Cl^-/Br^-$ ratios were discussed to accompany the dual isotope analysis for better assignment of contamination sources even when microbial transformation of nitrate and/or mixing between contaminant plumes occur.

• Ocean and Polar Research
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• 제26권2호
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• pp.175-185
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• 2004

To delineate Late Pleistocene paleoceanographic change of the West Pacific, we analyzed the oxygen and carbon isotopic ratios of two planktonic foraminifera species (G. sacculifer and N. dutertrei) from a piston core (KODOS-313) taken from the West equatorial Pacific, and they are compared with the published results of the East Pacific (ODP site 847 and RC 11-210), in terms of relative amounts and mass accumulation rates of $CaCO_3$ and eolian component, back to marine isotopic stage (MIS) 6. Differences in oxygen and carbon isotope values between two foraminifear species ($0.75%_{\circ}$ in ${\delta}^{18}O$, $0.05%_{\circ}$ in ${\delta}^{13}C$) are less than those of the East Pacific ($1.30%_{\circ}$ in ${\delta}^{18}O$, $0.14%_{\circ}$ in ${\delta}^{13}C$), which indicates smaller vertical contrasts in both temperature and nutrient between mixing-zone and thermocline in the West Pacific. Strong deviation in${\delta}^{18}O$ of G. sacculifer from SPECMAP suggests the carbonate fraction of KODOS-313 was subjected to partial dissolution by bottom water under lysocline. Lower accumulation rates of $CaCO_3$ and eolian component during glacial times are likely due to low sedimentation rate (ave. 0.75 cm/1000 yr) combined with carbonate dissolution in KODOS-313 site. However, the high $CaCO_3$ contents during the glacial periods clearly follow the general pattern of equatorial Pacific ocean.

• 센서학회지
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• 제1권2호
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• pp.173-181
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• 1992

RP 반응성 스펏터링으로서 P형 실리콘 웨이퍼위에 $Ta_{2}O_{5}$막을 제조하였다. 시편의 구조 및 조성은 XRD와 AES로 조사하였다. 산소의 혼합비가 10%일 때 C-V 특성으로부터 구한 $Ta_{2}O_{5}$막의 비유전률은 10-12이었다. AES와 RBS로 측정한 $Ta_{2}O_{5}$막의 Ta : O의 비는 각각 1 : 2와 1 : 2.49로 나타났으며, 산소분위기에서 $700^{\circ}C$의 열처리 온도에서 결정성장이 시작되었다. 산소분위기에서 $1000^{\circ}C$로 열처리한 $Ta_{2}O_{5}$막의 비유전률값은 20.5였으며, 질소분위기에서 열처리한 경우의 비유전률값은 23으로 나타났다. 이 때 가육방전계(pseudo hexagonal ${\delta}-Ta_{2}O_{5}$)의 결정구조를 나타내었다. 시편의 ${\Delta}V_{FB}$와 누설전류밀도는 산소의 혼합비가 증가함에 따라 감소하였다. 그리고 최대절연파괴전장은 산소가 10% 혼합되었을 때 2.4MV/cm로 나타났다. 이러한 $Ta_{2}O_{5}$막은 수소이온 감지막 및 기억용소자의 게이트 절연막 등에 응용될 수 있을 것이다.

• 한국해양환경ㆍ에너지학회지
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• 제13권1호
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• pp.53-59
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• 2010

일본 나나키다 하구 갯벌에 있어서 탄소 질소 안정동위원소를 이용해 먹이 연쇄의 공간적 가변성에 대해 조사했다. 서로 다른 특징을 갖고 있는 갯벌에서 잠재적인 유기물(육상식물, 해양 입자성 유기물, 저서 부착 미세조류 및 하구 입자성 유기물), 퇴적유기물 및 저서 무척추 동물(Nuttallia olivacea and Nereidae)에 대한 샘플링을 행했다. 본 연구의 목적은 좁은 공간적 가변성에 따른 Nuttallia olivacea와 Nereidae의 먹이원을 결정하는 것이다. 육상식물(${\delta}^{13}C=-26.6{\pm}0.76$, ${\delta}^{15}N=2.7{\pm}0.31$) 과 하구 입자성 유기물(${\delta}^{13}C=-25.5{\pm}0.13$, ${\delta}^{15}N=5.2{\pm}0.46$)은 저서 부착 미소조류${\delta}^{13}C=-16.3$, ${\delta}^{15}N=6.2$)와 해양 입자성 유기물(${\delta}^{13}C=-19.6{\pm}0.08$, ${\delta}^{15}N=8.9{\pm}1.70$)의 탄소 질소 안정동위원소비 보다 낮았다. 퇴적물의 탄소 안정동위원소 비는 -27.4~-22.8‰ 나타냈으며, 하구에서 하천 방향으로 갈수록 낮은 탄소 안정동위 원소비를 나타냈다. 저서 무척추 동물의 탄소 질소 안정동위원소비는 각각 -22.8~-18.4‰, 8.1~11.9‰ 범위를 나타냈다. 이러한 결과와 더불어 혼합 모델을 이용해 저서 무척추 동물의 먹이원의 기여율을 추정한 결과 해양 입자성유기물과 저서 부착 미세조류의 기여율은 높았지만, 육상식물과 하구 입자성 유기물의 기여율은 비교적 낮았다. 이러한 저서 무척추 동물의 먹이 기여는 각 장소마다 계절 및 물리적 환경 요소의 영향을 받는다고 사료된다.