• Title/Summary/Keyword: microstructural stability

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Durability Prediction of Door W/H System Using FEM Analysis (전면 도어 와이어하니스 시스템의 내구 수명 예측에 관한 연구)

  • Kim, Byeong Sam;Lim, Kwangkyu
    • Journal of Auto-vehicle Safety Association
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    • v.5 no.2
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    • pp.51-56
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    • 2013
  • In vehicle's door wiring harness (W/H) system is more toward to arrange a passenger compartment than a hinge and a weatherstrip. An opening/closing member of a vehicle is attached to a vehicle by a hinge in a manner enabling easy opening and closing of the opening/closing member. Such members include doors, such as side-doors and rear doors, and other opening/closing members, such as trunk lids. This article gives some insight into the dimensioning process, with special focus on large deflection analysis of wiring harness(W/H) in vehicle's door structures for durability problem. The Finite elements analysis for door wiring harness(W/H) is used for residual stresses and dimensional stability with bending flexible. Durability test data for slam test specimens were compared with the numerical predicted fatigue life for verification. The final testing of the component combines the effects of these microstructural features with the complex stress state arising from the combined service loading and residual stresses.

Microstructural Evaluation on the Quality of Tunnel Lining Concrete in Subway Structures (지하철 터널라이닝 콘크리트의 품질에 대한 미세구조적 평가)

  • Kim, Seong-Soo;Kim, Dong-Gyou;Lee, Gyu-Phil;Jung, Ho-Seop;Bong, Won-Yong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.593-596
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    • 2006
  • Recently, as it has greatly increased the demand on the serviceability of subway, cable tunnel, the stability of the tunnel structures has been attracting the concern of engineers and researchers. The purpose of this study is to idently the various characteristics of lining concrete in subway structures. The nondestructive technique such as the surface hardness method and the extend of carbonation by phenolphthalein indicator and chemical analysis due to XRD are considered. Also, the concrete core was cut in three pieces per tunnel for the exact evaluation of strength.

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Age Hardening and Microstructure in Rapidly Solidified Mg-Al-Si-xCa Alloys (급냉응고된 Mg-Al-Si-xCa 합금의 시효경화 및 미세조직)

  • Kim, Wan-Chul;Park, Ji-Ha;You, Bong-Sun;Park, Won-Wook
    • Journal of Korea Foundry Society
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    • v.19 no.5
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    • pp.433-439
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    • 1999
  • Rapidly solidified Mg-Al-Si base alloys containing Ca were obtained by melt spinning. The melt-spun ribbons were aged isochronally or isothermally to investigate age hardening phenomena and microstructural change according to the alloy composition. Age hardening occurred after aging at $200^{\circ}C$ for 1h mainly due to the precipitation of $Al_2Ca$ and $Mg_2Ca$, which have coherent interfaces with the matrix. With the increase of Ca content, the hardness values of the alloy ribbons were increased. Among the alloys, Mg-10Al-2 Si-3Ca alloy showed a good thermal stability at elevated temperature.

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Wear Characteristics of Coated $Si_3N_4$-TiC Ceramic Tool (Coated $Si_3N_4$-TiC Ceramic 공구의 마모 특성)

  • 김동원;권오관;이준근;천성순
    • Tribology and Lubricants
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    • v.4 no.2
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    • pp.44-51
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    • 1988
  • Titanium carbide(TiC), Titanium nitride(TiN), and Titanium carbonnitride(Ti(C,N)) films were deposited on $Si_3N_4$-TiC composite cutting tools by chemical vapor deposition(CVD) using $TiCl_4-CH_4-H_2$, $TiCl_4-N_2-H_2$, and $TiCl_4-CH_4-N_2-H_2$ gas mixtures, respectively. The experimental results indicate that TiC coatings compared with TiN coatings on $Si_3N_4$ -TiC ceramic have an improved microstructural property, good thermal shock resistance, and good interfacial bonding. However TiN coatings compared with TiC coatings have a low friction coefficient with steel and good chemical stability. It is found by cutting test that coated insert compared with $Si_3N_4$-TiC ceramic have a superior flank and crater wear resistance. And multilayer coating compared with monolayer coating shows a improved wear resistance.

Effect of sous-vide cooking conditions on the physicochemical, microbiological and microstructural properties of duck breast meat

  • Dong-Min Shin;Jong Hyeok Yune;Dong-Hyun Kim;Sung Gu Han
    • Animal Bioscience
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    • v.36 no.10
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    • pp.1596-1603
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    • 2023
  • Objective: Sous-vide cooking offers several advantages for poultry meat, including enhanced tenderness, reduced cooking loss, and improved product yield. However, in duck meat, there are challenges associated with using the sous-vide method. The prolonged cooking time at low temperatures can lead to unstable microbial and oxidative stabilities. Thus, we aimed to assess how varying sous-vide cooking temperatures and durations affect the physicochemical and microbial characteristics of duck breast meat, with the goal of identifying an optimal cooking condition. Methods: Duck breast meat (Anas platyrhynchos) aged 42 days and with an average weight of 1,400±50 g, underwent cooking under various conditions (ranging from 50℃ to 80℃) for either 60 or 180 min. Then, physicochemical, microbial, and microstructural properties of the cooked duck breast meat were assessed. Results: Different cooking conditions affected the quality attributes of the meat. The cooking loss, lightness, yellowness, Hue angle, whiteness, and thiobarbituric acid reactive substance (TBARS) values of the duck breast meat increased with the increase in cooking temperature and time. In contrast, the redness and chroma values decreased with the increase in cooking temperature and time. Cooking of samples higher than 60℃ increased the volatile basic nitrogen contents and TBARS. Microbial analysis revealed the presence of Escherichia coli and Coliform only in the samples cooked at 50℃ and raw meat. Cooking at lower temperature and shorter time increased the tenderness of the meat. Microstructure analysis showed that the contraction of myofibrils and meat density increased upon increasing the cooking temperature and time. Conclusion: Our data indicate that the optimal sous-vide method for duck breast meat was cooking at 60℃ for 60 min. This temperature and time conditions showed good texture properties and microbial stability, and low level of TBARS of the duck breast meat.

The effect of TiCrN coating on high temperature stability of Inconel 617 (TiCrN 코팅이 Inconel 617 합금의 고온안정성에 미치는 영향)

  • Lee, Byeong-Woo;Park, Jong-Cheon;Kim, Mi-Ru;Koo, Jin-Heui;Kim, Byeong-Ik;Cho, Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.6
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    • pp.235-239
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    • 2011
  • TiCrN layers (Ti : Cr = 20 : 80 and 5 : 95 wt%) were deposited on Inconel 617 and the effect of TiCrN coating on the high temperature stability of Inconel 617 up to $1000^{\circ}C$ was examined. XRD analysis and microstructural observation showed that vigorous and inhomogenous Cr diffusion to the surface was suppressed by TiCrN layer compare to the uncoated Inconel 617. This led to a distinctive enhancement in thermal oxidation resistance of Inconel 617.

Introduction of a Buffering Layer for the Interfacial Stability of LSGM-Based SOFCs (LSGM계 고체산화물 연료전지의 계면안정성을 위한 완층층의 도입)

  • Kim, Kwang-Nyeon;Moon, Jooho;Son, Ji-Won;Kim, Joosun;Lee, Hae-Weon;Lee, Jong-Ho;Kim, Byung-Kook
    • Journal of the Korean Ceramic Society
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    • v.42 no.9 s.280
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    • pp.637-644
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    • 2005
  • In order to find a proper buffering material which can prohibit an unwanted interfacial reaction between anode and electrolyte of LSGM-based SOFC, we examined a gadolinium doped ceria and scandium doped zirconia as a candidate. For this examination, we investigated the microstructural and phase stability of the interface under different buffering layer conditions. According to the investigation, ceria based material induced a serious La diffusion out of the LSGM electrolyte resulted in the formation of very resistive $LaSrGa_3O_7$ phase at the interface. On the other hand zirconia based material was directly reacted with LSGM electrolyte and thus produced very resistive reaction products such as $La_2Zr_2O_7,\;Sr_2ZrO_4,\;LaSrGaO_4\;and\;LaSrGa_3O_7$. From this study we found that an improper buffering material induced the higher internal cell resistance rather than an interfacial stability.

Corrosion Behavior of As-Cast and Solution-Treated AZ91-4%RE Magnesium Alloy (주조 상태 및 용체화처리한 AZ91-4%RE 마그네슘 합금의 부식 거동)

  • Han, Jin-Gu;Hyun, Soong-Keun;Jun, Joong-Hwan
    • Journal of the Korean Society for Heat Treatment
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    • v.31 no.5
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    • pp.220-230
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    • 2018
  • The objective of this study is to investigate the effect of solution treatment on the microstructure and corrosion behavior of cast AZ91-4%RE magnesium alloy. In the as-cast state, microstructure of the AZ91-4%RE alloy was characterized by intermetallic ${\beta}(Mg_{17}Al_{12})$, $Al_{11}RE_3$ and $Al_2RE$ phase particles distributed in ${\alpha}-(Mg)$ matrix. After solution treatment, the ${\beta}$ particles with low melting point dissolved into the matrix, but Al-RE phases still remained due to their high thermal stabilities. It was found from the immersion and potentiodynamic polarization tests that corrosion rate of the AZ91-4%RE alloy increased after the solution treatment. On the contrary, EIS tests and EDS compositional analyses on the surface corrosion products indicated that the stability of the corrosion product was improved after the solution treatment. Examinations on the corroded microstructures for the ascast and solution-treated samples revealed that dissolution of the ${\beta}$ particles which play a beneficial role in suppressing corrosion propagation, would be responsible for the deterioration of corrosion resistance after the solution treatment. This result implies that the microstructural features such as amount, size and distribution of secondary phases that determine corrosion mechanism, are more influential on the corrosion rate in comparison with the stability of surface corrosion product.

Physico-mechanical, AC-conductivity and microstructural properties of FeCl3 doped HPMC polymer films

  • Prakash, Y.;Somashekarappa, H.;Manjunath, A.;Mahadevaiah, Mahadevaiah;Somashekar, R.
    • Advances in materials Research
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    • v.2 no.1
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    • pp.37-49
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    • 2013
  • The transition metal salt doped solid polymer electrolyte [TSPE] were prepared with HPMC as a host polymer. The virgin and doped films were prepared by solution-casting method and investigated using wide angle X-ray scattering method. Micro structural parameters like lattice strain (g%), stacking/twin faults, the average number of unit cells counted in a direction perpendicular to the Bragg's plane (hkl) spacing of (hkl) planes dhkl, crystallite size Ds, distortion width, standard deviation were determined by whole pattern powder fitting (WPPF) method, which is an extension of single order method. It is found that the crystallite size decreases with the increase in the content of $FeCl_3$. This decrease is due to increase in localized breaking of polymer network which also accounts for the amorphous nature of the material. The filler inorganic salt $FeCl_3$ acts as plasticizer. FTIR study also confirms and justifies the interaction between the polymer and in-organic salt in the matrix. Physical properties like mechanical stability and Ac conductivity in these films are in conformity with the X-ray results.

Structural and Morphological Changes of Co Nanoparticles and Au-10at.%Pd Thin Film Studied by in Situ Heating in a Transmission Electron Microscope

  • Ji, Yoon-Beom;Park, Hyun Soon
    • Applied Microscopy
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    • v.47 no.3
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    • pp.208-213
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    • 2017
  • The microstructural changes in Co nanoparticles and an Au-10at.%Pd thin film have been investigated using an in situ heating holder with a micro-electro-mechanical system (MEMS). In Co nanoparticles, two phases (face-centered cubic and hexagonal close-packed crystal structures) were found to coexist at room temperature and microstructures at temperatures, higher than $1,000^{\circ}C$, were observed with a quick response time and significant stability. The actual temperature of each specimen was directly estimated from the changes in the lattice spacing (Bragg-peak separation). For the Au-10at.%Pd thin film, at a set temperature of $680^{\circ}C$, the actual temperature of the sample was estimated to be $1,020^{\circ}C{\pm}123^{\circ}C$. Note that the specimen temperature should be carefully evaluated because of the undesired effects, i.e., the temperature non-uniformity due to the sample design of the MEMS chip, and distortion due to thermal expansion.