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  1. No Access

    Article

    Superior Capacity in Electric Double-Layer Capacitors Employing Three-Dimensional Titanium Foam Electrodes

    In this study, Ti foams with 80 to 85 pct porosity and 300 to 500 μm pore size were fabricated using a unique space holder method. Because of their large surface area originated from sufficiently small pore size ...

    Gigap Han, Youngseok Song in Metallurgical and Materials Transactions A (2023)

  2. Article

    Open Access

    Different Evolutions of the Microstructure, Texture, and Mechanical Performance During Tension and Compression of 316L Stainless Steel

    The tensile and compressive behaviors of 316L stainless steel at room temperature were compared. The differences between the stress–strain responses during tension and compression were explained by the differe...

    Moustafa El-Tahawy, Péter Jenei in Metallurgical and Materials Transactions A (2020)

  3. No Access

    Article

    The effects of lithium and yttrium substitution on the optical and structural properties of cobalt ferrites

    Known as a hard magnetic material, cobalt ferrite belongs to one of the most attractive classes of materials owing to its diverse technical applicability such as in catalysis, sensors, batteries. In this study...

    M. K. Shobana, Ho-Seok Nam, Heeman Choe in Indian Journal of Physics (2019)

  4. No Access

    Article

    Effects of Powder Carrier on the Morphology and Compressive Strength of Iron Foams: Water vs Camphene

    With its well-known popularity in structural applications, considerable attention has recently been paid to iron (Fe) and its oxides for its promising functional applications such as biodegradable implants, wa...

    Hyeji Park, Teakyung Um, Kicheol Hong in Metallurgical and Materials Transactions B (2018)

  5. No Access

    Article

    Mechanical behavior of Li-ion-conducting crystalline oxide-based solid electrolytes: a brief review

    Li-ion-conducting solid electrolytes are receiving considerable attention for use in advanced batteries. These electrolytes would enable use of a Li metal anode, allowing for batteries with higher energy densi...

    Jeff Wolfenstine, Jan L. Allen, Jeff Sakamoto, Donald J. Siegel, Heeman Choe in Ionics (2018)

  6. No Access

    Article

    Anode Design Based on Microscale Porous Scaffolds for Advanced Lithium Ion Batteries

    Considering the increasing demands for advanced power sources, present-day lithium-ion batteries (LIBs) must provide a higher energy and power density and better cycling stability than conventional LIBs. This ...

    Hyeji Park, Hyelim Choi, Kyungju Nam, Sukyung Lee in Journal of Electronic Materials (2017)

  7. No Access

    Article

    Morphology and Gas-Sensing Properties of Tin Oxide Foams with Dual Pore Structure

    Tin oxide is a commonly used gas-sensing material, which can be applied as an n- or p-type gas sensor. To improve the gas-sensing performance of tin oxide, we successfully synthesized tin oxide foam via an ice-te...

    Kyungju Nam, Hyeong-Gwan Kim, Hyelim Choi, Hyeji Park in Journal of Electronic Materials (2017)

  8. No Access

    Article

    Structural and electrical properties of Cr doped nickel ferrite

    The Chromium doped Nickel ferrite nanopowders prepared by sol–gel combustion route by nitrates of respective metal ions. Formation of structure, morphology has been confirmed by X-ray powder diffraction method...

    M. K. Shobana, Heeman Choe in Journal of Materials Science: Materials in Electronics (2016)

  9. No Access

    Article

    Processing, Microstructure, and Oxidation Behavior of Iron Foams

    With its historically long popularity in major structural applications, the use of iron (Fe) has also recently begun to be explored as an advanced functional material. For this purpose, it is more advantageous...

    Hyeji Park, Yoonsook Noh, Hyelim Choi in Metallurgical and Materials Transactions A (2016)

  10. No Access

    Article

    Effect of Yttrium on the Fracture Strength of the Sn-1.0Ag-0.5Cu Solder Joints

    This is a preliminary investigation on the mechanical properties of Pb-free Sn-1.0Ag-0.5Cu solder joints containing 0.02 wt.% to 0.1 wt.% Y under a range of thermal aging and reflow conditions. Despite the sig...

    Hyelim Choi, Wayne D. Kaplan, Heeman Choe in Journal of Electronic Materials (2016)

  11. No Access

    Article

    Morphological Study of Directionally Freeze-Cast Nickel Foams

    Nickel foams, consisting of 51 to 62 pct aligned, elongated pores surrounded by a network of Ni walls, were fabricated by reduction and sintering of directionally cast suspensions of nanometric NiO powders in ...

    Hyungyung Jo, Min Jeong Kim, Hyelim Choi in Metallurgical and Materials Transactions E (2016)

  12. Article

    Open Access

    3D macroporous electrode and high-performance in lithium-ion batteries using SnO2 coated on Cu foam

    A three-dimensional porous architecture makes an attractive electrode structure, as it has an intrinsic structural integrity and an ability to buffer stress in lithium-ion batteries caused by the large volume ...

    Ji Hyun Um, Myounggeun Choi, Hyeji Park, Yong-Hun Cho in Scientific Reports (2016)

  13. No Access

    Article

    In situ investigation of deformation mechanisms in magnesium-based metal matrix composites

    We studied the effect of short fibers on the mechanical properties of a magnesium alloy. In particular, deformation mechanisms in a Mg-Al-Sr alloy reinforced with short alumina fibers were studied in situ usin...

    Gergely Farkas, Heeman Choe, Kristián Máthis in Metals and Materials International (2015)

  14. Article

    Open Access

    Facile and Gram-scale Synthesis of Metal-free Catalysts: Toward Realistic Applications for Fuel Cells

    Although numerous reports on nonprecious metal catalysts for replacing expensive Pt-based catalysts have been published, few of these studies have demonstrated their practical application in fuel cells. In thi...

    Ok-Hee Kim, Yong-Hun Cho, Dong Young Chung, Min Jeong Kim, Ji Mun Yoo in Scientific Reports (2015)

  15. No Access

    Article

    Ordered macroporous platinum electrode and enhanced mass transfer in fuel cells using inverse opal structure

    Three-dimensional, ordered macroporous materials such as inverse opal structures are attractive materials for various applications in electrochemical devices because of the benefits derived from their periodic...

    Ok-Hee Kim, Yong-Hun Cho, Soon Hyung Kang, Hee-Young Park in Nature Communications (2013)

  16. No Access

    Article

    Structure of Cu-Sn Melt at High Temperature

    The temperature-dependent viscosity and X-ray diffraction (XRD) patterns of a Cu65Sn35 melt were investigated at high temperatures. The viscosity of the melt changed discontinuously at about 1283 K (1010 °C). An ...

    J. X. Hou, C. W. Zhan, X. L. Tian, X. C. Chen in Metallurgical and Materials Transactions A (2012)

  17. No Access

    Article

    Mechanical properties of the solid Li-ion conducting electrolyte: Li0.33La0.57TiO3

    Li0.33La0.57TiO3 (LLTO) is a potential Li-ion conducting membrane for use in aqueous Li-air batteries. To be in this configuration its mechanical properties must be determined. Dense LLTO was prepared using a sol...

    Yong-Hun Cho, Jeff Wolfenstine, Ezhiylmurugan Rangasamy in Journal of Materials Science (2012)

  18. No Access

    Article

    Fracture behavior of Cu-cored solder joints

    Copper-cored solder can be regarded as the next-generation solder for microelectronic semiconductors exposed to harsh operating conditions owing to its excellent sustainability under extreme thermal conditions...

    Yunsung Kim, Hyelim Choi, Hyoungjoo Lee, Dongjun Shin in Journal of Materials Science (2011)

  19. No Access

    Article

    Predicting the Drop Performance of Solder Joints by Evaluating the Elastic Strain Energy from High-Speed Ball Pull Tests

    Despite being expensive and time consuming, board-level drop testing has been widely used to assess the drop or impact resistance of the solder joints in handheld microelectronic devices, such as cellphones an...

    Taehoon You, Yunsung Kim, **a Kim, Jaehong Lee in Journal of Electronic Materials (2009)