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검색결과 21,443건 처리시간 0.057초

sI 천연 메탄하이드레이드의 존재 : 결정구조 변화의 분광학적 분석 (Preponderant Occurrence of sl natural methane hydrates: Spectroscopic analysis of crystalline structure transition)

  • 연순화;설지웅;이흔
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.387-390
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    • 2006
  • We report here that under strong attacksof external $CH_4$ guest molecules the sII and sH methane hydrates are structurally transformed to the crystalline me framework of sI, leading to favorable change of the lattice dimension of the host-guest networks. The High Power Decoupling $^{13}C$ NMR and Raman spectroscopies were used to identify structure transitions of the mixed $CH_4+C_2H_6$ hydrates (sIIl) and hydrocarbons (methylcyclohexane, isopentane) + $CH_4$ hydrates (sH). The resulting spectra indicate that most of the synthesized sII and sH hydrates were transformed to methane hydrate of sl under 110 bar and particularly the coexistence of sl with sII or sH appear according to the surrounding methane-rich gas conditions. The present findings might be expected to Provide rational evidences regarding the preponderant occurrence of naturally-occurring sI methane hydrates in marine sediments.

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Mathematical Models to Predict Staphylococcus aureus Growth on Processed Cheeses

  • Kim, Kyungmi;Lee, Heeyoung;Moon, Jinsan;Kim, Youngjo;Heo, Eunjeong;Park, Hyunjung;Yoon, Yohan
    • 한국식품위생안전성학회지
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    • 제28권3호
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    • pp.217-221
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    • 2013
  • 본 연구는 가공치즈에서 Staphylococcus aureus의 생장을 예측하기 위한 수학적 모델을 개발하였다. 모짜렐라 슬라이스 치즈와 체다 슬라이스 치즈에 S. aureus 혼합균액(ATCC13565, ATCC14458, ATCC23235, ATCC27664, NCCP10826) 0.1 ml (log CFU/g)을 접종한 후 $4^{\circ}C$ (1440 h), $15^{\circ}C$ (288 h), $25^{\circ}C$ (72 h), and $30^{\circ}C$ (48 h)에 저장하면서 총 세균수와 S. aureus 세균수를 tryptic soy agar와 mannitol salt agar를 이용해 각각 확인하였다. S. aureus의 세균 수를 Baranyi model로 분석하여 생장률(${\mu}_{max}$; ${\log}CFU{\cdot}g^{-1}{\cdot}h^{-1}$), 유도기(LPD; h), 초기 세균 수(log CFU/g), 최대 생장 세균수(log CFU/g)를 계산함으로써 1차 모델을 개발하였다. 또한 저장온도와 S. aureus의 ${\mu}_{max}$, LPD의 관계를 분석하기 위해 square root model과 exponential decay model을 이용하였고 이를 통해 2차모델을 개발하였으며 개발된 모델의 평균제곱근 편차(RMSE)를 계산하여 적합성을 검증하였다. $4^{\circ}C$에서는 모든 가공치즈에서 황색포도상구균의 생장이 관찰되지 않았으나 $15^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$에서는 모짜렐라 슬라이스와 체다 슬라이스 치즈에서 황색포도상구균이 생장하였으며($R^2=0.785-0.996$) 저장온도가 높아짐에 따라 생장률은 증가한 반면 유도기는 감소하였다($R^2=0.879-0.999$). 또한 개발된 모델의 RMSE 값은 0.3500-0.5344로 적합하였다. 따라서 본 연구결과는 가공치즈에서 황색포도상구균의 생장 예측에 유용하게 사용될 것이다.

Position of the hyoid bone and its correlation with airway dimensions in different classes of skeletal malocclusion using cone-beam computed tomography

  • Shokri, Abbas;Mollabashi, Vahid;Zahedi, Foozie;Tapak, Leili
    • Imaging Science in Dentistry
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    • 제50권2호
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    • pp.105-115
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    • 2020
  • Purpose: This study investigated the position of the hyoid bone and its relationship with airway dimensions in different skeletal malocclusion classes using cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans of 180 participants were categorized based on the A point-nasion-B point angle into class I, class II, and class III malocclusions. Eight linear and 2 angular hyoid parameters(H-C3, H-EB, H-PNS, H-Me, H-X, H-Y, H-[C3-Me], C3-Me, H-S-Ba, and H-N-S) were measured. A 3-dimensional airway model was designed to measure the minimum cross-sectional area, volume, and total and upper airway length. The mean crosssectional area, morphology, and location of the airway were also evaluated. Data were analyzed using analysis of variance and the Pearson correlation test, with P values <0.05 indicating statistical significance. Results: The mean airway volume differed significantly among the malocclusion classes(P<0.05). The smallest and largest volumes were noted in class II (2107.8±844.7 ㎣) and class III (2826.6±2505.3 ㎣), respectively. The means of most hyoid parameters (C3-Me, C3-H, H-Eb, H-Me, H-S-Ba, H-N-S, and H-PNS) differed significantly among the malocclusion classes. In all classes, H-Eb was correlated with the minimum cross-sectional area and airway morphology, and H-PNS was correlated with total airway length. A significant correlation was also noted between H-Y and total airway length in class II and III malocclusions and between H-Y and upper airway length in class I malocclusions. Conclusion: The position of the hyoid bone was associated with airway dimensions and should be considered during orthognathic surgery due to the risk of airway obstruction.

Thiobacillus sp. IW의 고정화특성에 관한 연구 (The Immobilization Characteristics of Thiobacillus sp. IW)

  • 김성미;오광중김동욱
    • KSBB Journal
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    • 제11권6호
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    • pp.649-653
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    • 1996
  • 황산화박테리아인 Thiobacillus sp. IW를 사용한 황함유악취 제거장치를 제작하기 위한 기초자료로서 균의 최적성장조건, 활성탄과 bioceramics에서의 고 정화특성을 조사하였다. Thiobacillus sp. IW는 최척 성장조건이 pH 7, $30^{\circ}C$이고, 이때 세대시간이 38 분으로 다른 황산화균에 비해 아주 빠른 성장속도를 보여주었다. 균의 최적성장조건은 활성탄을 담체로 사용할 경우 pH 5, $35^{\circ}C$였으며, bioceramic의 경우 pH 7~8, $35^{\circ}C$로 액상배양시와는 상이한 성장조건 을 보여주었다. pH, 온도의 변화에 대한 균의 성장은 활성단보다 bioceramics에서 보다 안정적이었고, 총균수도 많았다. 전체적으로 균의 성장속도면에서 는 bioceramics가 활성탄보다 우수한 담체로 사료된다.

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OPPOSITE SKEW COPAIRED HOPF ALGEBRAS

  • Park, Junseok;Kim, Wansoon
    • 충청수학회지
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    • 제17권1호
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    • pp.85-101
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    • 2004
  • Let A be a Hopf algebra with a linear form ${\sigma}:k{\rightarrow}A{\otimes}A$, which is convolution invertible, such that ${\sigma}_{21}({\Delta}{\otimes}id){\tau}({\sigma}(1))={\sigma}_{32}(id{\otimes}{\Delta}){\tau}({\sigma}(1))$. We define Hopf algebras, ($A_{\sigma}$, m, u, ${\Delta}_{\sigma}$, ${\varepsilon}$, $S_{\sigma}$). If B and C are opposite skew copaired Hopf algebras and $A=B{\otimes}_kC$ then we find Hopf algebras, ($A_{[{\sigma}]}$, $m_B{\otimes}m_C$, $u_B{\otimes}u_C$, ${\Delta}_{[{\sigma}]}$, ${\varepsilon}B{\otimes}{\varepsilon}_C$, $S_{[{\sigma}]}$). Let H be a finite dimensional commutative Hopf algebra with dual basis $\{h_i\}$ and $\{h_i^*\}$, and let $A=H^{op}{\otimes}H^*$. We show that if we define ${\sigma}:k{\rightarrow}H^{op}{\otimes}H^*$ by ${\sigma}(1)={\sum}h_i{\otimes}h_i^*$ then ($A_{[{\sigma}]}$, $m_A$, $u_A$, ${\Delta}_{[{\sigma}]}$, ${\varepsilon}_A$, $S_{[{\sigma}]}$) is the dual space of Drinfeld double, $D(H)^*$, as Hopf algebra.

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Development of OCB mode with impulsive driving scheme for improving moving picture quality

  • Kim, J.L.;Lee, C.H.;Park, S.Y.;Yoo, S.W.;Oh, J.H.;Lee, S.H.;Chai, C.C.;Park, C.W.;Ban, B.S.;Ahn, S.H.;Hong, M.P.;Chung, K.H.;Lim, S.K.;Kim, K.H.;Souk, J.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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    • pp.1049-1052
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    • 2004
  • In general, contrary to the CRTs with impulsive emission, liquid crystal displays have motion artifacts such as blurring. ghost image, decrease of dynamic CR(contrast ratio), and stroboscopic motion due to hold type driving method. In this paper, to improve motion picture quality of LCDs. impulsive driving method of black data insertion was applied to the OCB mode which is well known for its fast LC response time and wide viewing angle properties. Subject evaluation was carried out with CRT, TN, SIPS(Super IPS). and impulsive driving OCB. Moving picture image quality near CRT was obtained in impulsive OCB driving mode

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60MHz PECVD법에 의한 ${\mu}c$-Si:H 박막의 저온증착 및 태양전지 응용 (Microcrystalline Silicon Thin-film(${\mu}c$-Si:H) and Solar Cells prepared at Low Temperature by 60MHz PECVD)

  • 이정철;정연식;김석기;윤경훈;송진수;박이준;권성원;임광수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 C
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    • pp.1595-1597
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    • 2003
  • This paper presents the deposition of ${\mu}c$-Si:H thin-film and fabrication of a solar cell by VHF-PECVD method. The ${\mu}c$-Si:H thin films and pin-type solar cells are fabricated using multi-chamber cluster tool system. A 7.4% conversion efficiency was achieved from ${\mu}c$-Si:H thin film solar cells with total thickness less than $5{\mu}m$. The physical characteristic was measured by Raman spectroscopy, Solar cell characteristic was measured under AM1.5 illumination.

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Dry Etching Process for the Fabrication of Transparent InGaZnO TFTs

  • Yoon, S.M.;Cheong, W.S.;Hwang, C.S.;Kopark, S.H.;Cho, D.H.;Shin, J.H.;Ryu, M.;Byun, C.W.;Yang, S.;Lee, J.I.;Chung, S.M.;Chu, H.Y.;Cho, K.I.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.222-225
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    • 2008
  • We proposed the dry etching process recipe for the fabrication of In-Ga-Zn-O (IGZO)-based oxide TFTs, in which the etching behaviors of IGZO films were systematically investigated when the etching gas mixtures and their mixing ratios were varied. Good device characteristics of the fabricated TFT were successfully confirmed.

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RBL-2H3 세포에서 Cyanidin-3-glucoside의 Th2 사이토카인 발현 억제 효과 (Suppressive Effects of Cyanidin-3-glucoside on Th2 Cytokines Production in RBL-2H3 Cells)

  • 정화현;윤수정;표명윤
    • 약학회지
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    • 제57권5호
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    • pp.309-315
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    • 2013
  • Cyanidin-3-glucoside (C3G), an anthocyanin, is one of the most widespread dietary flavonoids. We investigated the effects of C3G in PMA/ionomycin (PI)-induced RBL-2H3 cells. C3G inhibited the production of IL-4 and IL-13 and also decreased the level of mRNA in a dose-dependent manner. Furthermore, western blot analysis implied that C3G down-regulated the protein level of c-Jun, NF-ATc1 and NF-${\kappa}B$ but not c-Fos. Taken together, we suggest that C3G may have suppressive effects on Th2 cytokines and will be studied further to develop as functional foods that help alleviate allergy symptoms.

산화아연을 이용한 고온 탈황 실험 (Desulfurization of hot syngas using zinc oxide sorbent)

  • 정기진;유영돈;김나랑;김문현;김정헌;김병환
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 추계학술대회 초록집
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    • pp.177.2-177.2
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    • 2011
  • 폐기물 합성가스에 포함되어 있는 오염물질 중 황화합물($H_2S$, COS)이 존재할 경우, 다른 연계 공정을 구성하는 설비의 부식, 합성가스 이용 공정의 촉매 피독 문제, 대기 배출시 환경오염 문제 등을 야기 시키므로 제거가 필요하다. 고온 정제 공정을 적용하여 황화합물을 제거하기위해 산화아연을 이용한 고온 탈황 실험을 수행하였다. 고정층 반응기에 탈황제로 선정한 산화아연을 충진하고, 공간속도 $3,000h^{-1}$, 입구 황화합물의 농도 $H_2S$ 1,000ppm, COS 300ppm일 때 반응 온도 변화에 따른 탈황특성을 살펴보았다. 가스 내부에 $H_2S$가 단독으로 존재할 경우에는 $400^{\circ}C$ 이상에서 모두 제거되었으나, $H_2S$와 COS가 동시에 존재할 경우에는 $450^{\circ}C$ 이상에서 모두 제거되는 것을 알 수 있었다. 반응온도 $500^{\circ}C$에서 산화아연 탈황제를 이용한 실험결과 $H_2S$, COS의 파과시간은 각각 1,217, 1,063 min, 흡착능력은 269.9 mg-$H_2S$/g-sorbent, 124.7 mg-COS/g-sorbent으로 파악되었다.

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