• 제목/요약/키워드: chemical stress

검색결과 1,230건 처리시간 0.024초

The Effect of Growth Temperature on the Epitaxial Growth of Vertically Aligned ZnO Nanowires by Chemical Vapor Deposition

  • 임소영;이도한;장삼석;김아영;변동진
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 추계학술발표대회
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    • pp.21.1-21.1
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    • 2011
  • Vertically aligned single-crystal ZnO nanowires have been successfully grown on c-plane sapphire substrate using chemical vapor deposition (CVD) without catalyst. According to growth temperatures, it was changed ZnO growth characteristic. We investigated the effect of substrate temperatures on the growth ZnO films or nanowires on c-plane (0001) sapphire substrates. The ZnO films were acquired at $500^{\circ}C$, whereas the ZnO nanowires were obtained at $600^{\circ}C$, $700^{\circ}C$, and $800^{\circ}C$. The growth behavior diameter and growth rate of ZnO were changed due to different temperature. As a result of analyzing in-plane residual stress by X-ray diffraction, the optimized condition of ZnO nanowires were at $600^{\circ}C$.

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Protective effect of KR-32000 against hypoxia- and oxidative stress-induced cardiac cell death

  • Kim, Mi-Jeong;Yoo, Sung-Eun;Yi, Kiu-Yang;Lee, Sun-Kyung;Lee, Soo-Hwan;Baik, Eun-Joo;Moon, Chang-Hyun;Jung, Yi-Sook
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.297.3-298
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    • 2002
  • A benzopyranyl derivative. KR32000. synthesized as a plausible KATP opener. has been shown to exert cardioprotective effect in vivo myocardial infarct model. In this study. we investigated whether KR32000 can produce cardioprotective effect against hypoxia- and reactive oxygen species(ROS)-induced injury in heart-derived H9c2 cells. Hypoxic injury was induced by incubating cells in anaerobic chamber (glucose-free. serum-free DMEM. 85% N2. 5% CO2. 10% H2) and oxidative stress was induced by buthionine sulfoximine(BSO). (omitted)

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Compressive rheology of aggregated particulate suspensions

  • Gladman Brendan;Usher Shane P.;Scales Peter J.
    • Korea-Australia Rheology Journal
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    • 제18권4호
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    • pp.191-197
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    • 2006
  • The measurement of the compressional rheological parameters for an aggregated particulate suspension is described. The parameters include the compressive yield stress and hindered settling function, describing the extent and rate of dewatering respectively. The variation of these parameters with shear rate and time of shear is also considered in the light of their sensitivity to low shear rates, with particular reference to the case of flocculated particulate suspensions. The latter is seen to be important in the future development of a comprehensive understanding of compressive rheology of aggregated particulate suspensions in industrial applications such as thickening, filtration and centrifugation.

금속소재 부품의 고장분석 사례 (Failure Analysis of Metallic Components)

  • 송진화;홍기정;장창환;김영섭
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제6권1호
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    • pp.51-61
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    • 2006
  • Failure analyses were conducted on a crank shaft and a chock liner by using X-ray diffraction, optical microscopy and SEM/EDS techniques. In the crank shaft, a crack developed where a maximum tensile stress coincided with band structure formed by hot forging. The maximum tensile stress was observed to originate from volume expansion during high frequency induction heat treatment and the band structure to develop between upper and lower dies during hot forging. In the chock liner, the wear mechanism varied with the chemical affinity and hardness of liner material relative to friction pair of housing liner. Brass of low chemical affinity and hardness compared to housing liner showed uniform adhesive wear. STS 304 and STS 420J2 of high chemical affinity showed galling and scoring respectively.

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DUFOUR AND HEAT SOURCE EFFECTS ON RADIATIVE MHD SLIP FLOW OF A VISCOUS FLUID IN A PARALLEL POROUS PLATE CHANNEL IN PRESENCE OF CHEMICAL REACTION

  • VENKATESWARLU, M.;BABU, R. VASU;SHAW, S.K. MOHIDDIN
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제21권4호
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    • pp.245-275
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    • 2017
  • The present investigation deals, Dufour and heat source effects on radiative MHD slip flow of a viscous fluid in a parallel porous plate channel in presence of chemical reaction. The non-linear coupled partial differential equations are solved by using two term perturbation technique subject to physically appropriate boundary conditions. The numerical values of the fluid velocity, temperature and concentration are displayed graphically whereas those of shear stress, rate of heat transfer and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. By increasing the slip parameter at the cold wall the velocity increases whereas the effect is totally reversed in the case of shear stress at the cold wall. It is observed that the effect of Dufour and heat source parameters decreases the velocity and temperature profiles.

Effect of alpha-tocopheryl acetate, retinyl palmitate, and phytantriol on hair protection

  • Ki Young Ahn;Hong Jong Song;Dong Chung Kim
    • Journal of Applied Biological Chemistry
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    • 제65권4호
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    • pp.307-312
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    • 2022
  • A hair essence containing α-tocopheryl acetate, retinyl palmitate, and phytantriol (TRP-hair essence) was prepared. TRP-hair essence was excellent in thermal stability to the extent that it did not harden at all even at 210 ℃. TRP-hair essence potently protected the hair from heat stress, significantly reducing the protein leakage in heat-treated hair (p <0.001). Treatment of TRP-hair essence to dyed human hair significantly protected hair against heat stress (p <0.05) as well as improved hair cuticle and color persistence (p <0.05). In addition, as a result of directly treating human hair with TRP-hair essence, the cuticle and tensile strength of human hair were significantly improved (p <0.05). These results suggest that TRP-hair essence can be effective for hair protection and hair quality improvement.

Ni-Ti 형상기억합금의 전해가공의 특성 (ECM Characteristics of Ni-Ti Shape Memory Alloy)

  • 김동환;강지훈;박규열
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 추계학술대회 논문집
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    • pp.955-958
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    • 2000
  • In this paper, the electro-chemical-machining characteristics of Ni-Ti Shape Memory Alloy(SMA) was investigated. From the experimental results, the optimal electro chemical machining conditions for satisfying the machining quality(fine surface & high recovery stress)might be confirmed. And it was concluded that optical electro chemical condition for Ni-Ti SMA could be obtained at approximately 100% current efficiency and high frequency pulse current.

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공업용수배관의 응역부식균열 거동에 관한 연구 (Study on the Stress Corrosion Cracking Behaviour of Piping for Industrial Water)

  • 임우조;이진평
    • 수산해양기술연구
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    • 제33권3호
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    • pp.194-201
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    • 1997
  • Recently with the rapid development in the industries such as an iron mill and chemical plants, these are enlarged by the use of the piping. This piping was encountered the stress corrosion cracking(SCC) because of stress by water pressure and residual stress of welding etc. under industrial water. In this paper, the behaviour of stress corrosion cracking on the weld zone of steel pipe piping water(SPPW) were investigated according to pre-heat before welding in natural seawater(specific resistance : 25$\Omega$-cm). The main results obtained are as follows :1) The stress corrosion cracking for SPPW and SB 41 is most ready to propagate in heat affected zone of weldment. 2) The SCC sensitivity of SPPW on weldment is more susceptible than that of SB 41. 3) The stress corrosion cracking growth of heat affected zone is delayed by the preheat and dry of base metal and electrode before welding.

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Proteomic Analysis of the Oxidative Stress Response Induced by Low-Dose Hydrogen Peroxide in Bacillus anthracis

  • Kim, Sang Hoon;Kim, Se Kye;Jung, Kyoung Hwa;Kim, Yun Ki;Hwang, Hyun Chul;Ryu, Sam Gon;Chai, Young Gyu
    • Journal of Microbiology and Biotechnology
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    • 제23권6호
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    • pp.750-758
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    • 2013
  • Anthrax is a bacterial disease caused by the aerobic spore-forming bacterium Bacillus anthracis, which is an important pathogen owing to its ability to be used as a terror agent. B. anthracis spores can escape phagocytosis and initiate the germination process even in antimicrobial conditions, such as oxidative stress. To analyze the oxidative stress response in B. anthracis and thereby learn how to prevent antimicrobial resistance, we performed protein expression profiling of B. anthracis strain HY1 treated with 0.3 mM hydrogen peroxide using a comparative proteomics-based approach. The results showed a total of 60 differentially expressed proteins; among them, 17 showed differences in expression over time. We observed time-dependent changes in the production of metabolic and repair/protection signaling proteins. These results will be useful for uncovering the metabolic pathways and protection mechanisms of the oxidative response in B. anthracis.