• 제목/요약/키워드: $\delta^{15}N$

검색결과 307건 처리시간 0.027초

$(Sr_{1-x}{\cdot}Ca_x)_mTiO_3$ 입계층 세라믹의 유전특성에 관한 연구 (Study on the Dielectric Properties of $(Sr_{1-x}{\cdot}Ca_x)_mTiO_3$ Grain Boundary Layer Ceramics))

  • 김진사;최운식;신철기;김성렬;이준웅
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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    • pp.215-218
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    • 1994
  • $(Sr_{l-x}{\cdot}Ca_x)_mTiO_3+0.006Nb_2O_5$($0.05{\leq}x{\leq}0.2$, 0.996$N_2$)에서 소결시킨 후 CuO를 시편의 양면에 도포하여 $1100^{\circ}C$에서 2시간동안 열처리함으로써 제작하였다. 결정립의 크기는 Ca의 치환량이 증가함에 따라 촉진되었으나, 20[mol%] 이상 치환시 더 이상 고용되지 못하고 입성장을 억제시켰다. Ca의 치환량이 $10{\sim}15[mol%]$, m=1인 시편에 있어서 우수한 유전특성을 나타내었다. 즉, 비유전율, 유전손실($tan{\delta}[%]$)과 온도변화에 따른 정전용량의 변화율이 각각 >25,000, <0.3[%], <${\pm}10[%]$을 나타내었다. 본 연구에 사용된 모든 시편은 온도의 함수로서 주파수 증가에 따라 유전완화 현상을 나타내었으며, 분산주파수는 $10^6[Hz]$ 이상이었다.

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춘천 중도 유적에서 출토된 원삼국시대 토기 탄착물에 대한 화학적 분석 (Organic Analysis of Charred Residues on the Pottery in the Proto-Three Kingdom from Joong-do Site, Chuncheon)

  • 강소영;지상현;김윤지;장홍선
    • 보존과학회지
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    • 제29권4호
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    • pp.437-444
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    • 2013
  • 춘천 중도 유적에서 출토된 원삼국시대 경질무문토기 내부의 탄화된 물질에 대한 화학적 분석을 실시하였다. 가스크로마토그래피-질량분석과 퓨리에변환적외선분광분석을 이용하여 부착물에서 유래한 유기물의 정성분석을 수행한 결과, 지방산, 스테롤 등 지방성분이 검출되지 않았다. 탄소와 질소 안정동위원소 분석 결과 부착물을 구성하고 있는 탄소 안정동위원소 비는 평균 $-14.7{\pm}2.8$‰ (-8.7‰~-18.4‰, n=9), 질소 안정동위원소 비는 평균 $6.2{\pm}1.1$‰(-4.4‰~-7.6‰, n=9)로 나타났는데 이 결과는 부착물이 조리된 음식물에서 유래되었음을 추정할 수 있는 과학적 근거라고 할 수 있다. 본 연구결과는 안정동위원소 분석을 조리용 토기 내 탄화된 잔존물 분석에 적용한 국내 첫 사례로서 당시의 토기 용도와 식생활 습관에 대한 중요한 정보를 제공할 것으로 기대된다.

조선시대 회곽묘 출토 인골의 안정동위원소 분석을 통한 아산 명암리 피장자의 식생활 복원 (Stable Isotopic Reconstructions of Diets in Joseon Dynasty Using Human Remains from Myeongam-ri Site, Asan)

  • 강소영;김윤지;조은민;김수훈
    • 헤리티지:역사와 과학
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    • 제49권4호
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    • pp.38-51
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    • 2016
  • 본 연구는 아산 명암리 유적에서 출토된 조선시대 전기 인골에 대한 탄소와 질소 안정동위원소 분석을 통해 당시의 식생활 양상을 복원하고자 하였다. 21기의 회곽묘에서 출토된 25개체 인골의 탄소와 질소 안정동위원소 분석결과, 탄소 안정동위원소 값은 평균 $-19.7{\pm}0.5$‰(n=23), 질소 안정동위원소 값은 평균 $9.6{\pm}1.1$‰(n=23)로 나타났다. 탄소와 질소 안정동위원소 값을 통해 아산 명암리 피장자들은 주로 $C_3$ 식물을 주식으로 섭취하였으며 육상동물에 의한 단백질 섭취 수준을 확인하였다. 선행 연구된 조선시대 인골의 안정동위원소 분석결과와 함께 조선시대 식생활 양상을 비교했을 때 지역이나 무덤양식에 의한 차이는 확인되지 않았다. 다만 합장묘에서 출토된 인골의 질소 안정동위원소 값 비교를 통해 동일한 생활환경 피장자의 성별간 차이가 있는 것으로 나타났다.

한국산 식물식용유지의 성분에 관한 연구 - 제 6 보 : 참깨와 들깨종자유 중의 천연산화방지제에 관한 연구 - (Studies on the Constituents of Korean Edible Oils and Fats - Part 6 : A Study on the Natural Antioxidants of sesame and perilla seeds -)

  • 황성자;고영수
    • Journal of Nutrition and Health
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    • 제15권1호
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    • pp.30-38
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    • 1982
  • Experiments were carried out in order to compare the natural antioxidants in the acetonitril extracts of raw and baked seeds of Korean sesame and perilla by thin layer and gas chromatography. The sample was dissolved in n-pentane and extracted with acetonitril and the acetonitril extract was separated by thin layer chromatography using silica gel. The spots were detected by spraying with 2, 6 -dichloroquinone -4-chlorimide, phosphomolybdic acid and dimethylamine as chromogenic reagents. Natural antioxidant, such as ${\delta}-tocopherol$ detected in raw and baked sesame and perilla seed oil by TLC and sesamol was detected only in raw and baked sesame seed oil by GC.

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DFT Study on the Different Oligomers of Glycerol (n=1-4) in Gas and Aqueous Phases

  • Valadbeigi, Younes;Farrokhpour, Hossein
    • 대한화학회지
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    • 제57권6호
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    • pp.684-690
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    • 2013
  • Since a glycerol molecule has three active sites, two ${\alpha}$ and one ${\beta}$ hydroxyl groups; it undergoes condensation by releasing water molecules to produce linear, nonlinear and heterocyclic oligomers. The Gibbs free energy (G), enthalpy (H) and internal energy (E) of 7 diglycerol, 15 triglycerol and 23 tetraglycerol isomers were calculated at B3LYP level of theory using 6-311++G(d, p) basis set, in both gas and aqueous phases. Linear oligomers, ${\alpha}{\alpha}$-diglycerol, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-triglycerol and ${\alpha}{\alpha}$, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-tetraglycerol, were found to be the most stable oligomers in aqueous phase. It was found that the stability of cyclic oligomers decreases as the size of their rings increases. Cyclic oligomers are produced by dehydration of the acyclic ones which is an endothermic reaction while its ${\Delta}G$ is negative. The dehydration reaction is less endothermic in aqueous phase.

Synthesis and Biological Investigations of New Thiazolidinone and Oxadiazoline Coumarin Derivatives

  • Abd Elhafez, Omaima Mohamed;El Khrisy, Ezz El Din Ahmed Mohamed;Badria, Farid;Fathy, Alaa El Din Mohamed
    • Archives of Pharmacal Research
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    • 제26권9호
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    • pp.686-696
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    • 2003
  • Ethyl (coumarin-4-oxy)acetate 1 was prepared through the reaction of 4-hydroxycoumarin with ethyl bromoacetate. Compound 1 was allowed to react with hydrazine hydrate to produce coumarin-4-oxyacetic hydrazide 2. The synthesis of N-(arylidene and alkylidene)-coumarin-4-oxyacetic hydrazones 3-20 was performed. The preparation of 2-substituted-3-[(coumarin-4-oxy) acetamido]thiazolidinones 21-26 and 2-[(coumarin-4-oxy )methyl]-4-acetyl-5-substituted-$\Delta^2$-1,3,4-oxadiazolines 27-33 was performed by the reaction of the hydrazones 3, 4, 7, 9, 12, 14 with mercaptoacetic acid and the hydrazones 3, 4, 5, 7, 12, 15, 16 with acetic anhydride, respectively. The antiviral activities, cytotoxicities and structure-activity relationship (SAR) towards different microorganisms of the prepared compounds were studied.

合谷($LI_4$), 三間($LI_3$)의 電針刺戟이 顔面部 領域 溫度變化에 미치는 影響 (Effects on the Thermal Change of the Face Follow Electroacupunctyre on Hapkok($LI_4$), Sangan($LI_3$))

  • 윤정훈;김종한;황충연;임규상
    • 한방안이비인후피부과학회지
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    • 제12권2호
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    • pp.222-247
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    • 1999
  • The back ground and purpose : The acupuncture of oriental medicine is very important in treatments. Until now it has been researched according to the meridian and qi xue(氣血) phenomenon of oriental medicine's theory. As electroacupuncture is one of acupuncture treatments, it will show more objective index to observe the meridian and qi xue(氣血) phenomenon. And then, I studied the effects on the thermal change of the face following electroacupuncture treatment. Objective and Methods : This study was performed from January 1999 to March 1999 on 10 healthy students. The objective was divided into three groups, those were the control group A(n=10), the group B(n=10) of electroacupuncture on Hapkok($LI_4$), Samgan($LI_3$) and the group C(n=10) of electroacupuncture on Shinmun($H_7$), T' ongni($H_5$). First, in the control group A, we took a picture for 10 men without any stimulation with the Digital Infrared Thermograph Imaging(D.I.T.I.) and did 3min after, 10min after, 15min after, 25min after, 45min after respectively. Second, in the electroacupuncture treatment group B, we took a picture for 10 men without any stimulation, and then treat electroacupuncture on Hapkok($LI_4$), Samgan($LI_3$) and took a picture immediately(3min after), 10min after, 15min after and remove needle and took a picture in the same way respectively. Third, in the electroacupuncture treatment group C, we took a picture for 10 men without any stimulation, and then treat electroacupuncture on Shinmun($H_7$), T'ongni($H_5$) and took a picture in the second way respectively. Results: 1. In healthy men, average skin temperture about Yonghyang($LI_{20}$) area was higher than Soryo($G_{25}$) or Chich'ang($S_4$) area. They were Soryo($G_{25}$) area $31.495{\pm}0.766^{\circ}C$, Rt. Yonghyang($LI_{20}$) area $31.664{\pm}0.936^{\circ}C$, Lt. Yonghyang ($LI_{20}$)area $31.686{\pm}0.767^{\circ}C$, Rt. Chich'ang($S_4$) area $31.226{\pm}0.875^{\circ}$, Lt. Chich'ang ($S_4$) area $31.453{\pm}0.855^{\circ}C$. 2. In the control group A, the skin temperature of Soryo($G_{25}$) showed the increase or decrease in below ${\Delta}0.1^{\circ}C\;except\;0.265{\pm}0.594^{\circ}C$ in 25min, but not significantly. 3. About Soryo($G_{25}$) area, the skin temperature decreased significantly after electroacupuncture immediately. ${\Delta}T $of the group B was $-0.970{\pm}0.87\;1^{\circ}C$, which was larger than one of the group C which was $-0.707{\pm}0.624^{\circ}C$ at 3min. And then ${\Delta}T$ of the group C was increase valuable at 25min, 45min. 4. About Yonghyang($L1_{25}$) area, the left ${\Delta}T$ of the group B showed below $0.2^{\circ}C$ or so in contrast to the right it. In the group C, on the both side showed continous increase of temperature as following times. 5. About Chich'ang($S_4$) area, the skin temperature increased valuable $0.3^{\circ}C$ or so on the both side and later inclined to decrease in the group B but not significantly. In the group C, it increased valuable on the both side. 6. The skin temperature of electroacupuncture treatment group B, C were more increase than the control group A except Lt. Yonghyang($LI_{20}$) area in the group B. The temperature of group C were more increase than the group B wholly. Conclusion : The above results indicate that D.I.T.I. is a useful method to observe and fallow-up the effects and the changes by electroacupuncture stimulation on objective evaluation of phenomenon for the meridian system and character. Thus, continuous thermographic study will be needed for more clinical application such as acupuncture and medicine or laser therapy according to oriental medicine.

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Influence of multiple holes on the magnetic properties of YBCO superconductor

  • Oh, W.S.;Oh, S.K.;Jang, G.E.;Kim, C.J.;Han, Y.H.;Jung, S.Y.;Sung, T.H.
    • 한국초전도ㆍ저온공학회논문지
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    • 제11권2호
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    • pp.15-19
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    • 2009
  • Bulk $YBa_2Cu_3O_{7-{\delta}}$ (YBCO) superconductor was manufactured with the top-seeded melt grown method. The 9, 16, and 25 holes, as small as 0.7mm in diameter, parallel to the c-axis were mechanically drilled. Magnetic flux mapping and levitation force were measured and compared to estimate the influence of multiple holes on the magnetic properties of YBCO superconductor at 77K. According to the measurements, the maximum magnetic flux density obtained from the plain sample was 2.48kG, while the maximum magnetic flux density of the sample with 25 holes was low as around 2.29kG. The levitation force measured on the sample with 9 holes increased from 91N to 105N. The levitation force measured on the samples with 9 holes is relatively higher than the plain sample without any holes. In this case, increase of the levitation force in the perforated samples could be explained by enhancement of the cooling efficiency more effectively. We investigated that the magnetic properties of YBCO superconductor were strongly influenced by the artificial holes.

장기간의 고지방 식이 섭취가 골격근 내 PPAR Isoforms 유전자 발현에 미치는 영향 (The Effects of Dietary Interventions on mRNA Expression of Peroxisome Proliferator Activated Receptor Isoforms (PPAR Isoforms) in Rat Skeletal Muscle)

  • 이장규;김정규;문희원;신영오;이종삼
    • Journal of Nutrition and Health
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    • 제40권3호
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    • pp.221-228
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    • 2007
  • We determined the effects of dietary manipulations on messenger RNA of peroxisome proliferators activated receptor isoforms (i.e., PPAR ${\alpha},\;{\beta}/{\delta},\;{\gamma}$) in red vastus lateralis muscle of rats. Total 16 male Sprague-Dawley rats were used, and animals were divided into one of two dietary conditions: either chow diet group (CHOW; n=8) in which animals were 134 with standard rodent chow (61.8% carbohydrate, 15.7% fat, 22.5% protein) or high fat diet group (FAT n=8) in which animals were fed 24.3% carbohydrate, 52.8% fat, 22.9% protein. At the end of the 8 weeks of experimental period, red vastus lateralis muscle was dissected out from all animals, and PPAR ${\alpha},\;{\beta}/{\delta},\;{\gamma}$ mRNA expression was determined. There was no significant difference in body mass (BM) between CHOW and FAT. As expected, blood glucose and free fatty acid (FFA) concentration was higher in FAT than CHOW (p<0.05), and lactate concentration was significantly lower in FAT compared to CHOW (p<0.05). Insulin concentration tended to higher in FAT than CHOW ($67.2{\pm}21.9\;vs.\;27.0{\pm}5.2$ pmol/L), but it did not reach to the statistical significance. Gene expression of PPAR ${\alpha}$ was not significantly different between CHOW and FAT. It was not also significantly different in PPAR ${\beta}/{\delta}$. Interestingly, expression of mRNA in PPAR ${\gamma}$ however, was markedly depressed in FAT compared to CHOW (approximately 3 fold higher in CHOW; p<0.05). Results obtained from present study implies that PPAR ${\gamma}$ (as compensatory function of PPAR ${\alpha}$ is expressed) possibly exerts another major tuning roles in fatty acid transport, utilization, as well as biosynthesis in skeletal muscle cells. The situations and conditions that can be postulated for this implication need to be further examined.

(Sr.Ca)$TiO_3$계 입계층 세라믹의 Ca변화량에 따른 미세구조 및 유전특성 (Microstructure and dielectric properties with a contents Ca of (Sr.Ca)$TiO_3$-based grain boundary layer ceramics)

  • 최운식;김충혁;이준웅
    • E2M - 전기 전자와 첨단 소재
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    • 제7권6호
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    • pp.534-542
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    • 1994
  • Microstructures and dielectric properties of (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$+0.006Nb$_{2}$O$_{5}$ (0.05.leq.x.leq.0.2) ceramic were investigated. The specimens fired in a reducing atmosphere(N$_{2}$) were painted on the surface with CuO paste, and then annealed at 1100.deg. C for 2 hr. SEM and EDAX revealed that CuO penetrated rapidly into the bulk along the grain boundaries during the annealing. Grain size increased with increasing Ca content up to 15[mol%], but decreased with further addition. In the specimens with 10-15[mol%l of Ca, excellent dielectric properties were obtained as follows; dielectric constant <25000, dielectric loss(tan .delta[%]) <0.3[%] and capacitance change rate with temperature <.+-.[%], respectively. All the specimens in this study exhibited dielectric relaxation with frequency as a function of the temperature. The dispersive frequency was over 10$^{6}$ [Hz].z].

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