• Title/Summary/Keyword: internal barrier

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Evaluation of the Mechanical Characteristics According to the Curvature of Thermal Barrier Coating (가스터빈 블레이드 열차폐코팅의 곡률에 따른 기계적 특성 평가)

  • Lee, Jeng-Min;Seok, Chang-Sung;Koo, Jae-Mean;Kim, Sung Hyuk;Zhen, Guo;Tao, Shen;Moon, Wonki
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.12
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    • pp.1427-1430
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    • 2014
  • A thermal barrier coating (TBC) prevents heat directly transferring from a high-temperature flame to a substrate. The TBC system comprises a top coating and bond coating. TBC technology reduces the substrate surface temperature by about $100{\sim}170^{\circ}C$. In the TBC system, internal stress is generated by the difference in thermal expansion coefficients of the substrate and coating. The internal stress also differs according to the shape and position of the blade. In this study, finite element analysis was performed for different curvatures of coin-shaped specimens, which are commonly used for thermal fatigue tests, and the changes in internal stress of the TBC system were compared. Based on the results, the curvature at which the minimum stress occurs was derived, and the thermal stress was confirmed to increase with the difference between a given curvature and the curvature with the minimum stress.

Effects of injection route, volume and concentration of mannitol on blood-brain barrier disruption (Mannitol의 주입 경로와 양 및 농도가 혈-뇌 장벽 손상에 미치는 효과)

  • Cha, Myeoung-Hoon;Lee, Kyu-Hong;Lee, Chul-Hyun;Chung, Myung-Ae;Sohn, Jin-Hun;Cheong, Chae-Joon;Lee, Bae-Hwan
    • Science of Emotion and Sensibility
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    • v.11 no.4
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    • pp.565-574
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    • 2008
  • Functions of human brain including sensibility and emotion may be affected by drugs mediated by the blood-brain barrier (BBB). The present study was performed to evaluate whether injection route, volume and concentration of mannitol could alter the degree of disruption of the BBB. Under urethane anesthesia, female Sprague-Dawley rats were infused with 20% mannitol into the right internal carotid artery (ICA). In the other group, intravenous injection of mannitol through the femoral vein was performed. Evans blue(EB) dye was used as a marker of BBB disruption. When mannitol was injected via the ICA, the content of EB dye in the ipsilateral hemisphere was markedly increased. However, the content of EB in the brain was not increased when mannitol was injected via the femoral vein, even though the volume or concentration of mannitol was increased. These results suggest that the BBB was disrupted only through ICA injection route and this may provide a useful strategy for transient opening of the BBB to control the functions of human brain.

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Clinical application of insect-based diet in canine allergic dermatitis

  • Lee, Kang-Il;Chae, Yeon;Yun, Taesik;Koo, Yoonhoi;Lee, Dohee;Kim, Hakhyun;So, Kyoung-Min;Cho, Woo Jae;Kim, Ha-Jung;Yang, Mhan-Pyo;Kang, Byeong-Teck
    • Korean Journal of Veterinary Research
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    • v.61 no.4
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    • pp.36.1-36.8
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    • 2021
  • The objective of this study was to evaluate the beneficial effects of the short-term application of insect-based diet in canine allergic dermatitis. Total 19 atopic dogs with concurrent cutaneous adverse food reactions were enrolled and classified into 3 groups. The treatment group (n = 7) was fed insect-based diet, the positive control group (n = 6) was fed salmon-based diet, and the negative control group (n = 6) was fed commercial or homemade diet for 12 weeks. The degree of skin lesions was evaluated based on canine atopic dermatitis extent and severity index (CADESI-4). Additionally, transepidermal water loss (TEWL) and pruritus visual analog scale were evaluated. All indices were evaluated every 4 weeks after the initial administration of hypoallergenic diets. In the treatment group, significant decrease in the CADESI-4 score was observed at 8 weeks compared to the baseline score (p = 0.031). There were significant differences in the CADESI-4 score between the groups at 8 weeks (p = 0.008), 12 weeks (p = 0.012), and TEWL at 12 weeks (p = 0.022). This preliminary result demonstrates the potential hypoallergenicity of an insect-based diet through features that diminish cutaneous lesions and skin barrier dysfunction.

Force-induced Unbinding Dynamics in a Multidimensional Free Energy Landscape

  • Hyeona, Chang-Bong
    • Bulletin of the Korean Chemical Society
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    • v.33 no.3
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    • pp.897-900
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    • 2012
  • We examined theory for force-induced unbinding on a two-dimensional free energy surface where the internal dynamics of biomolecules is coupled with the rupture process under constant tension f. We show that only if the transition state ensemble is narrow and activation barrier is high, the f-dependent rupture rate in the 2D potential surface can faithfully be described using an effective 1D energy profile.

The Role of the Epithelial Cell in Bronchial Asthma (천식에서 기도 상피세포의 역할)

  • Chung, Jin-Hong
    • Journal of Yeungnam Medical Science
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    • v.16 no.1
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    • pp.15-24
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    • 1999
  • Although traditionally viewed as a physical barrier between the host and a variety of inhaled irritants and pathogens, it has become clear that the epithelium has a much broader functional scope. Epithelial cells arc metabolically active and can play an important role in the regulation of the allergic inflammatory response. This review provides a consideration of the role of the epithelial cell as both a "target" for exogenous and endogenous stimuli and as an "effector" cell that is capable of producing a variety of products that can influence the inflammatory response in the airways.

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Characteristics of ZnO Varistors with Praseodymium Oxide

  • Lee, Sang-Ki;Cho, Sung-Gurl;Shim, Young-Jae
    • The Korean Journal of Ceramics
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    • v.5 no.4
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    • pp.357-362
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    • 1999
  • ZnO varistors containing cobalt, praseodymium and calcium oxides were prepared. The current-voltage charcteristics and microstructures of the specimens were investigated with respect to calcium addition and sintering temperature. The potential barrier heights and the carrier densities were estimated from C-V relations. The compatibility of Ag-Pd as an internal electrode for multilayer chip varistor was also examined.

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Theoretical Study on the Two-Dimensional Tunneling of Electrons and Photons (전자와 광자의 2차원적 터널링에 대한 이론적 연구)

  • Lee, Byoung-Ho;Lee, Wook
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.544-546
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    • 1995
  • Tunneling of an electron non-normally incident on a potential barrier is theoretically studied. Tunneling time and the position where an electron appears after the tunneling are derived using the phase time approach. The positions where photons appear after two-dimensional tunneling in a frustrated total internal reflection structure are also discussed.

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Prescriptional Survey About Crinical Application Of Sagoonjatang(四君子湯) In The Dongubogam(東醫寶鑑) (사군자탕(四君子湯)의 활용(活用)에 대한 방제학적(方劑學的) 고찰(考察))

  • Yun, Young-Gab
    • Herbal Formula Science
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    • v.9 no.1
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    • pp.11-34
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    • 2001
  • 1. Crinical applicational of Sagoonjatang are frequently used in internal disease, G.I.T(Gastro Intestianl Tract) disease, chronical fatigue, athma, etc. 2. Sagoonjatang adjacent prescriptions in pathological organs are the stomach, the spleen, the kidneys, the heart, the lungs. 3. Sagoonjatang partake chronic fatigue disease, G.I.T disease, pulmonary disease, brain blood barrier disease, infertility, vomiting of pregnancy, sedation of brain, healing mechanism, sweating regulation, urination, peripheral blood ciraculation, electrolyte blance, etc.

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Derivation of Current-Voltage Equation for OLED using Device Simulation

  • Lee, Sang-Gun;Hattori, Reiji
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1212-1215
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    • 2009
  • The theoretical equations for J-V characteristics in an OLED was derived according to the internal carrier emission equation based on a diffusion model at Schottky barrier contact and the mobility equation based on the Pool-Frenkel model. The J-V characteristics of OLED are presented using a behavioral model for analog systems (Verilog-A language), and the accuracy of this model was verified by comparing with the device simulation results.

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Outflow Characteristics of Nakdong River Plume (낙동강수의 유출특성에 관한 연구)

  • 김기철;김재중;김영의;한건모;최광규;장성태
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.8 no.4
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    • pp.305-313
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    • 1996
  • CTD measurements were conducted in the Nakdong estuary on the several sections or along-plume and cross-plume directions in 1993 and 1994. Internal Froude number Fi=0.22-0.35 in ebb tides and 0.14 in flood tides suggest that Nakdong river plume may go farther seawards in the along-plume direction with little mixing with the adjacent sea water after the construction of Nakdong river barrier. From Dadae-Po to Gaduk-Do section of cross-plume direction, three cores of low salinity were found. The main plume outflows from the newly made channel by cutting Ulsuk-Do after the construction of barrier. The low salinity core found near Gaduk-Do is the plume patch advected by tidal currents. Rossby deformation radius varied with the tidal cycle so that Coriolis effect is strengthened in flood tides to deepen the isohalines westwards to the Gaduk-Do site. Internal wavelike shape was found in the section of cross-plume direction during ebb tides. Richardson number of the section suggests the possibility of forming internal wave but more precise observations are necessary.

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