• 제목/요약/키워드: $\delta^{13}C$

검색결과 464건 처리시간 0.028초

록소프로펜 정의 생물학적 동등성 평가 (Bioequivalence of Loxoprofen Tablets)

  • 김수진;오인준;신상철;이용복;조행남;서순팔
    • 한국임상약학회지
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    • 제7권2호
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    • pp.73-80
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    • 1997
  • The bioequivalence of two loxoprofen tablets between the $Loxonin^{TM}$ (Dong Hwa Pharmaceutical Co., Ltd.) and the $Lokpen^{TM}$ (Dong Il Pharmaceutical Co., Ltd.) was evaluated. 12 normal male volunteers (age $21\sim27$ years old) were divided into two groups and a randomized cross-over study was employed. After one tablet containing 60 mg of loxoprofen sodium anhydrous was orally administered, blood was taken at predetermined time intervals and the concentration of loxoprofen in serum was determined with an HPLC method using UV/VIS detector. The pharmacokinetic parameters ($C_{max},\;T_{max}$, and $AUC_t$) were calculated and ANOVA was utilized for the statistical analysis of parameters. The results showed that the differences in $C_{max},\;T_{max}$, and $AUC_t$ between two tablets were $1.13\%,\;0\%,\;and\;0.69\%$, respectively The powers (1-${\beta}$) for $C_{max},\;T_{max}$, and $AUC_t$ were $84.88\%,\;88.61\%,\;and\;84.81\%$, respectively Detectable differences ($\delta$) and confidence intervals were all less than $20\%$. All of these parameters met the criteria of KFDA for bioequivalence, indicating that $Lokpen^{TM}$ tablet is bioequivalent to $Loxonin^{TM}$ tablet.

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$Ba[Mg_{1/3}(Nb_{0.2}Ta_{0.8})_{2/3}]O_3$ 세라믹스의 밀도가 유전특성에 미치는 영향 (Effect of Densities on Dielectric Properties of $Ba[Mg_{1/3}(Nb_{0.2}Ta_{0.8})_{2/3}]O_3$Ceramics)

  • 김재윤;김부근;김강언;정수태;조상희
    • 한국전기전자재료학회논문지
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    • 제13권6호
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    • pp.485-492
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    • 2000
  • The sintering characteristics and the effects of density on dielectric properties in 0.2Ba(Mg$_{1}$3(Nb$_{2}$3/)O$_3$-0.8Ba(Mg$_{1}$3//Ta$_{2}$3/)O$_3$ceramics were investigated. The samples were made by the powder mixing techniques with the two step calcining conditions. When the 1st and the 2nd calcining temperatures were 120$0^{\circ}C$ and the sintering temperature was 155$0^{\circ}C$the density of samples showed the highest value (7.45 g/cm$^3$, 98.5% of theoretical density) among them. The dielectric constant of samples was nearly independent of density but the tan $\delta$ and the temperature coefficient of dielectric constant decreased linearly with increasing of the density. The quality factor(Q$\times$f), the temperature coefficient of resonance frequency and the dielectric constant of Ba[Mg$_{1}$3(Nb$_{0.2}$/Ta$_{0.8}$)sub 2/3/]O$_3$ceramic were 79,548 GHz, +1.5 ppm/$^{\circ}C$ and 26 in the microwave range, respectively.ely.

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금속 Ca증기에 의한 고체 Nd 금속의 탈산 (Deoxidation of Solid Nd Metal by the Metal Calcium Vapour)

  • 최영진;김상욱;전병서;송창빈;오윤석;이영주
    • 한국재료학회지
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    • 제27권5호
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    • pp.237-241
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    • 2017
  • As a basic study for the removal of oxygen in solid Nd metal by metal Ca vapour, by using the thermodynamic data such as ${\Delta}G-T$ diagrams and Nd-O and Nd-Ca equilibrium diagrams, the amount of residual oxygen in solid Nd metal formed based on deoxidation reaction by Ca vapour, instead of by direct contact of solid Nd metal and Ca solution, was determined. Deoxidation experiments were carried out for solid Nd metal in a temperature range of $890{\sim}970^{\circ}C$ for 1h to 4h and content of addition Ca of 0.6~1.8 g (5~15 wt% of solid Nd metal). As a result, it was found that as deoxidation temperature increased, dissolved oxygen decreased. Especially, it was observed that a small amount of Nd-Ca alloy liquid was formed on the surface of the solid Nd metal sample deoxidized at $970^{\circ}C$ for approximately 1 hour. Also, it was found that if the content of addition Ca was 1.8 g (15 wt% of solid Nd metal) the amount of produced Nd-Ca alloy increased slightly. However, for the Nd sample with which the deoxidation reaction was performed at $930^{\circ}C$ for 4h with content of addition of Ca of 1.5 g (13 wt% of Nd metal), the residual oxygen was found to decreased to 12.00 ppm.

Physical and Chemical Characteristics of Sediments at Bam Islands in Seoul, Korea

  • Han, Mie-Hie;Kim, Jae-Geun
    • Journal of Ecology and Environment
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    • 제29권4호
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    • pp.389-398
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    • 2006
  • To examine sediment characteristics and find anthropogenic effects on riverine wetland ecosystems, paleoecological study was carried out at Bam islands in Seoul. Three hundred cm deep sediment cores were retrieved and dated with the lamination analysis method until 36 cm depth (1986). Sediments were divided into three zones based on the depth profiles of physico-chemical variables: below 160 cm depth (before 1968), between 160 and 40cm depths and above 40cm depth (after 1986). Physico-chemical characteristics were very variable between 160 and 40cm depths and this indicates unstable sedimentation environment. Even though heavy metal concentrations were relatively low, Cd and As contents have increased continuously. Dry mass accumulation rates during $1968{\sim}1986\;and\;1987{\sim}2003$ were 140 and $21\;kg\;m^{-2}\;yr^{-1}$, respectively. This was related to flooding intensity and duration. Bulk density, water content, loss on ignition, N, C, C/N ratio were very similar to other river delta but Ca, Na and K contents were 2 to 4 times higher than others. Heavy metal contents except Pb were lower or similar to those in other studied marshes in Korea. Heavy metal and Mg contents were correlated with each other and this suggests that the source of heavy metals be parent rock. From $^{13}C$ dating dates of organic materials in sediment, it is suggested that organic matter originated from the watershed and flooding intensity in the watershed might be responsible for the source of sediments. This study provides reference data for the comparison of sediment characteristics at islands in river and for the management of Bam islands.

울릉분지 퇴적물, 공극수 및 공기층 가스의 지화학적 특징 (Geochemical characteristics of sediment, pore water, and headspace gas in the Ulleung Basin)

  • 김지훈;박명호;류병재;이영주;진영근
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.373-376
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    • 2006
  • 본 연구의 목적은 동해 울릉분지의 제4기 후기 퇴적물 내의 유기물, 공극수와 메탄의 특징 및 상호작용을 규명하는데 있다. 연구지역에서 채취한 코어퇴적물을 원소 분석한 결과 C/N 및 C/S 비(wt. %)는 퇴적물 내 유기물이 주로 해양조류 기원을 가지고, 일반적인 해양 또는 정체 환경에서 퇴적되어Tdam을 지시한다. 그러나 Rock-Eval 열분석 결과는 유기물 기원이 육상식물(Type III)이고, 열적 성숙단계가 미성숙단계임을 보여준다. 이러한 원소분석과 열분석간의 상반된 결과는 유기물이 침강하는 동안 또는 퇴적 후 이루어진 강한 산화작용에 기인한 것으로 추정된다. 퇴적물 내 공극수의 황산염 농도가 퇴적물의 심도가 증가할수록 감소하며, 감소하는 경향은 크게 두 가지 (적선성, concave down)로 나누어진다. 이는 모든 코어에서 황산엽 환원작용이 일어나고 있음을 지시한다. 또한 직선선의 황산엽농도 구배는 무산소 메탄 산화작용(AMO)의 전형적인 특징이다. 황산염 농도의 수직적 구배를 이용하여 SMI(sulfate-methane interface) 심도를 계산하면, 남부울릉분지의 코어 (03GHP-01, 03GHP-02; <3.5mbsf)가 북부울릉분지 코어(01GHP-05, 01GHP-07, 03GHP-03, 03GHP-04, 03GHP-05; > 6mbsf)보다 낮은 값을 갖는다. 위와 같은 SMI 심도차는 메탄의 상부 분산량과 밀접한 관련있는 것으로 추정된다. 메탄가스의 탄소 안정동위원소 $({\delta}^{13}C)$ 분석값들은 -83.5%o에서 -69.5%o의 범위를 가지고 있고, 이산화탄소 환원작용($CO)_2$ reduction)에 의한 생물 (biogenic) 기원임을 지시한다.

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과거 3만년 동안 캘리포니아 남부와 중부지역의 고식생 변화와 북동태평양 대기 및 해양순환 변동과의 연관성 연구 (Interrelationship between Paleovegetation in Southern and Central California and Northeast Pacific Atmospheric and Oceanographic Processes over the Last ~30 kyr)

  • 서연지
    • Ocean and Polar Research
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    • 제41권3호
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    • pp.159-168
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    • 2019
  • Understanding the interaction between climate and the water cycle is critical especially in a drought sensitive region such as California. This study explored hydrologic changes in central and southern California in relation to the glacial-interglacial climate cycles over the last 30 thousand years. To do this, we reconstructed paleovegetation using plant wax carbon isotopic compositions (${\delta}^{13}C$) preserved in marine sediment cores retrieved from the central California continental shelf (ODP Site 1018) and Santa Barbara Basin (ODP Site 893A). The results were then compared to the existing sea surface temperature (SST) and pollen records from the same cores to understand terrestrial hydrology in relation to oceanographic processes. The Last Glacial was generally dry both in central and southern California, indicated by grassland expansion, confirming the previously suggested notion that the westerly storm track that supplies the majority of the precipitation in California may not have moved southward during the glacial period. Southern California was drier than central California during the Last Glacial Maximum (LGM). This drying trend may have been associated with the weakening of the California Current and northerly winds leading to the early increase in SST in southern California and decline in both offshore and coastal upwelling. The climate was wetter during the Holocene in both regions compared to the glacial period and forest coverage increased accordingly. We attribute this wetter condition to the precipitation contribution increase from the tropics. Overall, we found a clear synchronicity between the terrestrial and marine environment which showed that the terrestrial vegetation composition in California is greatly affected by not only the global climate states but also regional oceanographic and atmospheric conditions that regulate the timing and amount of precipitation over California.

헬리컬 노즐의 피치각에 따른 볼텍스 튜브의 성능특성에 관한 연구 (A Numerical Study on the Effect of Pitch Angle of Helical Nozzle on the Vortex Tube Performance Characteristics)

  • 오영택;김귀순
    • 한국유체기계학회 논문집
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    • 제19권1호
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    • pp.11-17
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    • 2016
  • In this paper, a numerical analysis was performed to investigate the effect of the pitch angle of a helical nozzle on the performance characteristics of a vortex tube. Three-dimensional numerical simulation has been performed with standard $k-{\varepsilon}$ turbulence model by using FLUENT 13.0. The effect of the pitch angle of helical nozzle was described in term of ${\beta}$. A CFD analysis was performed on ${\beta}=0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$. In order to realize the influence of ${\beta}$ on performances of the vortex tube. Computation results were expressed by the ${\beta}-{\Delta}T_{h,c}$ graph and radial profiles of axial velocity and swirl velocity. The results showed that ${\beta}$ which improves energy separation capacity of vortex tube was $5^{\circ}$ at ${\alpha}=0.33$, 0.5 and $10^{\circ}$ at ${\alpha}=0.33$. Besides, It was confirmed that the results were closely related to axial velocity and swirl velocity.

합성섬유를 증발매체로한 저농도 방사성액체폐기물 처리

  • 김태국;김길정;이영희
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1996년도 춘계학술발표회논문집(3)
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    • pp.513-518
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    • 1996
  • 저농도 방사성 액체폐기물의 최종 처리를 목적으로 본 연구에서는 면 35%와 Polyester 65%가 함유된 합성섬유를 증발매체로 하여 자연상태의 공기를 강제 송풍시키는 자연증발처리시설에서 증발에 영향을 미치는 주요 변수에 따라 증발 단위 면적당 Cs-137, Co-60을 함유한 방사성 폐액의 증발량측정 및 제염계수를 조사하였다. 증발효과는 유입공기의 습도가 낮고, 공기의 유속과 공급액의 유량이 증가하고 유입공기 및 폐액의 온도가 높아질수록 증발량이 증가하였다. 실험결과 유입된 공기는 1$0^{\circ}C$ 이상, 습도는 80% 이하, 공급폐액의 유량이 3.4 $\ell$/hr $m^2$ 이상, 공기유속은 1.14~l.47 m/sec 범위가 조업조건이며 이때 제염계수는 5.1 $\times$ $10^3$, 배출공기의 방사능 농도는 4.7$\times$$10^{-13}$ $\mu$Ci/$m\ell$ air로 측정되었다. 공급유량이 4.6$\ell$/hr.$m^2$와 공기유속이 1.47 m,/sec일때 최대 증발조건으로 나타났으며, 이때 증발량은 총 증발면적 11,250$m^2$ 에서 1.2 ㎥/hr로 측정되었으며 대기의 온.습도 및 풍속에 따른 실험을 통하여 달톤형 증발식의 Wind Factor [Eh = (0.0168 + 0.0141V)$\Delta$H]를 도출하였다.

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$Nd_2O_3$를 첨가한 ZnO Varistor의 전기적 특성 (The Electrical Properties with variation of ZnO Varistors with added of $Nd_2O_3$)

  • 조현무;이성갑
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.603-606
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    • 2004
  • ZnO varistor ceramics were fabricated with variation of addition of $Nd_2O_3$ amount and the sintering temperature was $l150^{/circ}C$. The average grain sizes were showed decreased from $13.8{\mu}m$ to $4.7{\mu}m$, and varistor voltages were increased from 398 V to 657 V by added amount of $Nd_2O_3$. Nonlinear coefficient a of all were with increasing the amount of $Nd_2O_3$ more than 60, in case of added on 0.1mol% $Nd_2O_3$ was 87. And leakage current were less than $1_{\mu}A$ with applied at 82% of varistor voltage. The clamping voltage ratio of the specimes added 0.1mol% $Nd_2O_3$ was 1.38 at applied 25A [$8/20{\mu}s$]. In the specimen added 0.1mol% $Nd_2O_3$, endurence of surge current and deviation of varistor voltage were 7000A/$cm^2$, $\Delta-2.08%$, respectively.

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경북청송지역 달기 탄산약수의 지화학적 수질특성과 생성기원 (Geochemical Water Quality and Genesis of Carbonated Dalki Mineral Water in the Chungsong Area, Kungpook)

  • 정찬호
    • 자원환경지질
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    • 제32권5호
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    • pp.455-468
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    • 1999
  • Carbonated mineral waters fo $Ca(Mg)-HCO_3$ type spring out fissure of Jurassic granite in the valley floor of the Chungsong area. The water has been long as a Dalki medicinal water because of its unique therapeutic effect against clacium deficit, stomach and skin troubles, ect. The water has a high $CO_2$ concentration ($P_{CO_2}$=0.51~1.12atm) and exhibits strong pH buffering (5.9~6.26) by $H_2CO_3/HCO_3$ couple. Electrical conductivity ranges from 1,900 to 3100 $\mu$S/cm. Environmental isotopic data $(^{2}H/^{1}H, ^{18}O/^{16}O \;and \;^3H)$ indicates that the water is of meteoric origin recharged in the Cretaceous sedimetary strata distributed in upper part of the catchment area at least before 1950s, The high $P_{co_2}$ and carbon isotope data (${\delta}^{13}C=-3\sim-0.2\textperthousand$) suggest that the potential source of carbonated mineral water was originated in deep-seated $CO_2$ as wel as aboundant carbonate minerals of sedimentary desimetary rocks. The major source minerals of the dissoved species in the carbonated mineral water appear to be carbonate minerals, albite and K-feld-spar in sedimentrary rocks.

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