• Title/Summary/Keyword: Cycling Behavior

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The thermal cycling stability of V-Ti based alloy

  • Park, Jeoung-Gun;Kim, Dong-Myung;Jang, Kuk-Jin;Han, Jai-Sung;Lee, Jai-Young
    • Transactions of the Korean hydrogen and new energy society
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    • v.9 no.3
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    • pp.111-118
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    • 1998
  • The intrinsic degradation behavior of $(V_{0.53}Ti_{0.47})_{0.925}Fe_{0.075}$ alloy with BCC structure and the two plateau regions (the low and high plateau region) has been investigate during the temperature-induced hydrogen absorption-desorption cycling (thermal cycling). After 400 thermal cycles between room temperature and $600^{\circ}C$ under 10atm $H_2$, the total reversible hydrogen absorption capacity decreased by about 40%. From thermal desorption analysis it was found that the degradation behavior at each plateau region was different. In addition, XRD analysis showed that the crystal structure of the sample in de-hydrided state was changed from BCC to BCT after degradation, and that of the sample in hydrided state it was maintained as FCC although peaks were broadened after degradation. From the result of static isothermal hydrogenation treatment it were found that crystal structure change from BCC to BCT was caused by the thermal energy. TEM analysis showed that the peak broadening was due to the formation of an amorphous phase in FCC matrix.

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The Effect of F-treatment on the Degradation Behavior of the $CaNi_{5}$ and MG-$CaNi_{5}$ Electrodes ($CaNi_{5}$ 및 MG-$CaNi_{5}$ 전극의 퇴화거동에 미치는 불화처리의 영향)

  • Lee, C.R.;Oh, S.J.;Kang, S.G.
    • Korean Journal of Materials Research
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    • v.9 no.6
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    • pp.622-629
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    • 1999
  • Effects of the fluorination in the $K_2$TiF\ulcorner solution and in-situ KF+ KOH electrolyte on the electrochemical charge-discharge properties of CaNi\ulcorner and the Mg-CaNi\ulcorner electrodes were investigated. In-situ fluorination in the KF+ KOH electrolyte compared with pre-fluorination in the$ K_2$TiF\ulcorner solution could improve the electrochemical cycling durability of CaNi\ulcorner and MG-CaN\ulcorner electrodes. The fluorinated layer on the alloy surface by pre-fluorination to improve the activity and anti-corrosion of the electrodes was dissolved in the pure KOH electrolyte during the cycling. The fluorinated layer was formed continuously on the surface of the electrode by thee2N KF addition in the 6N KOH electrolyte. The excess F\ulcorner ion addition in KOH electrolyte could improve the electrochemical cycling durability of CaNi\ulcorner and Mg-CaNi\ulcorner electrode. But, in case of MG-CaNi\ulcorner electrode, the discharge capacity of the electrode was reduced and the poor cycling property was shown with increasing of the MG process times.

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eWOM Information Search Behavior of Cycle Wear (사이클웨어에 대한 전자 구전 정보 탐색 행동)

  • Choi, Jin Woo;Lee, Yuri
    • Journal of the Korean Society of Costume
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    • v.63 no.8
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    • pp.156-170
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    • 2013
  • The purpose of this research is to scrutinize the cyclist's consumer behavior by analyzing the eWOM information search behavior of cycle-wear according to benefits sought and involvement. The research was conducted through an online survey and the respondents were 291 men who wore cycle-wear and searched information via online. The results of this research are as following. First, the benefits sought from wearing cycle apparel are composed of five sub-factors such as, ideal body figure, brand ostentation, comfort ease, personality, and economic feasibility. In addition, the cycle-wear involvement consisted of two sub-factors: cycling involvement and fashion involvement. Second, the eWOM information search behavior of cyclists was different depending on the benefits sought by the cyclists. When the cyclists pursued ideal body figure they searched more information of design and color, while cyclists put more weight on the information of design, color, and brand when they sought brand ostentation. Moreover, the valence and the type of the information were dissimilar depending on the benefits sought. Third, the sub-factors of eWOM information search behavior affected the eWOM effect distinctively. The price information was the only factor that influenced the eWOM effect among the contents of the information. The valence of the information influenced the eWOM effect, and the effect of positive information was stronger than negative information. Additionally, the subjective information also affected the eWOM effect. Lastly, the effect of the benefits sought influencing the eWOM information search behavior varied by the difference of the cycle-wear involvement. For example, when they are both high in the involvement there were various benefits sought affecting the eWOM information search behavior. However, when only the cycling involvement was high, and they pursued personality, the price information was not important to them.

Cycling life prediction method considering compressive residual stress on liner for the filament-wound composite cylinders with metal liner (금속재 라이너를 갖는 복합재 압력용기의 라이너 압축잔류응력을 고려한 반복수명 예측 방법에 대한 연구)

  • Park, Ji-Sang;Jeung, Sang-Su;Chung, Jae-Han
    • Composites Research
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    • v.19 no.1
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    • pp.22-28
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    • 2006
  • In manufacturing process of composite cylinders with metal liner, the autofrettage process which induces compressive residual stress on the liner to improve cycling life can be applied. In this study, a finite element analysis technique is presented, which can predict accurately the compressive residual stress on the liner induced by autofrettage and stress behavior after. Material and geometrical non-linearity is considered in the finite element analysis, and the Von-Mises stress of a liner is introduced as a key parameter that determines pressure cycling life of composite cylinders. Presented methodology is verified through fatigue test of liner material and pressure cycling test of composite cylinders.

Effects of Silica Filler and Diluent on Material Properties of Non-Conductive Pastes and Thermal Cycling Reliability of Flip Chip Assembly

  • Jang, Kyung-Woon;Kwon, Woon-Seong;Yim, Myung-Jin;Paik, Kyung-Wook
    • Journal of the Microelectronics and Packaging Society
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    • v.10 no.3
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    • pp.9-17
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    • 2003
  • In this paper, thermo-mechanical and rheological properties of NCPs (Non-Conductive Pastes) depending on silica filler contents and diluent contents were investigated. And then, thermal cycling (T/C) reliability of flip chip assembly using selected NCPs was verified. As the silica filler content increased, thermo-mechanical properties of NCPs were changed. The higher the silica filler content was added, glass transition temperature ($T_g$) and storage modulus at room temperature became higher. While, coefficient of thermal expansion (CTE) decreased. On the other hand, rheological properties of NCPs were significantly affected by diluent content. As the diluent content increased, viscosity of NCP decreased and thixotropic index increased. However, the addition of diluent deteriorated thermo-mechanical properties such as modulus, CTE, and $T_g$. Based on these results, three candidates of NCPs with various silica filler and diluent contents were selected as adhesives for reliability test of flip chip assemblies. T/C reliability test was performed by measuring changes of NCP bump connection resistance. Results showed that flip chip assembly using NCP with lower CTE and higher modulus exhibited better T/C reliability behavior because of reduced shear strain in NCP adhesive layer.

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A Study on the Behavior of Ambient Hydraulic Cycling Test for 70 MPa Type3 Hydrogen Composite Cylinder (70 MPa용 Type 3 수소 복합용기의 상온수압반복 거동에 관한 연구)

  • Cho, Sung-Min;Kim, Chang-Jong;Kim, Young-Gyu
    • Journal of the Korean Institute of Gas
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    • v.16 no.1
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    • pp.46-50
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    • 2012
  • The performance of the Type3 hydrogen composite cylinder whose pressure is 70 MPa using hydrostatic cycling test equipment was evaluted in this study. It also includes the finite element method analysis on the performance of the cylinder when the pressure is applied. As a result, cylinder body parts of the Type3 hydrogen composite cylinder, which draws attention with its safe status and the lightness, was ruptured first and the same result has been found out through the finite element method. The dome knuckle and the cylinder body were proved as the weakest parts since the cylinder body parts was expanded under the pressure.

A Study on the Up-cycling Furniture Design Using the Korea Traditional Patchwork Technique - Focusing on the Production of Stitch Furniture Design - (조각보 기법을 활용한 업사이클링(Up-cycling) 가구디자인 연구 - Stitch 작품가구 제작 중심으로 -)

  • Kim, Ja-hyung;Yoon, Yeoh-hang
    • Journal of the Korea Furniture Society
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    • v.27 no.1
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    • pp.49-58
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    • 2016
  • In modern society, designers started feeling moral and social responsibility in the aspect of environment as a position of suggesting something new. Rather than creating another waste to make something innovative, the concept of Upcycling which is about adding design or utilization to the existing recyclable materials to raise their value to products or art works has started settling down. Among them, there have been various researches on the use of offcut waste to be dumped. Such use of waste can be found in Jogakbo (patchwork), one of our traditional boudoir crafts. This could be connected to the concept of the modern Upcycling in the aspect of giving new values to the wasted pieces of fabric through needlework. Therefore, this study suggested Stitch work as new Upcycling furniture by seeking for the common connections between Upcycling and traditional Jogakbo, and then reinterpreting them in the same viewpoint. It was an opportunity not only to rediscover 'the esthetics of waste' by changing the awareness of 'behavior of dumping', but also to reinterpret or reconsider the tradition. Based on this, it is expected to continuously have new attempts to use offcut waste for eco-friendly design in the future, and also to have opportunities to seek for new directions of Upcycling to rediscover new values through the revaluation of valuelessness.

Finite-element modeling and analysis of time-dependent thermomechanical distortion of optical sheets in a LCD module

  • Lee, Jae-Won;Hwang, Hak-Mo;Chung, In-Jae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1436-1441
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    • 2006
  • Each type of optical sheets in a LCD module experiences a characteristic behavior for thermal loading and unloading. During thermal cycling, a polymeric behavior is reversible and recyclable, depending on a material stiffness critically affected by temperature and time. Some critical issues on temperature- and time-dependent themomechanical deformation of the polymeric sheet are addressed by finite-element thermal results, followed by structural simulation results in this study.

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