• Research Paper

    Effect of Laser Radiation on the Structural, Electrical and Thermal Properties of the Bi1.9Sb0.1Ba1.9Y0.1Ca2Cu3O10+δ Superconducting Compound
    Laheeb Ahmed Mohammed, Kareem Ali Jasim, Nabaa Safaa Hamzah, Alaa Kadhim Shwyyea
    Laser can be used to precisely and locally modify the properties of superconductors. Their crystal structure and charge distribution can be altered … + READ MORE
    Laser can be used to precisely and locally modify the properties of superconductors. Their crystal structure and charge distribution can be altered by applying focused energy, thus affecting their microstructure and electrical properties. This technique enables the design and development of new materials with enhanced performance for various applications. This paper focuses on the effect of laser irradiation on the thermal, structural, and electrical properties of the Bi1.9Sb0.1Ba1.9Y0.1Ca2Cu3O10+δ superconducting compound. Samples were exposed to heat for 48 h at 900 °C at a heating rate of 10 °C/min. X-ray diffraction (XRD) studies were performed and the diffraction results showed that all samples had a regular orthorhombic crystalline structure and that the lattice constants (a, b, c) changed with irradiation compared to the unirradiated sample. A significant increase in the c/a axis, lattice size high-temperature phase (HTP) was also observed after irradiation. The content of the high-temperature phase increased to 81.47 %. The topographical nature of the samples was examined using scanning electron microscopy (SEM), and a change in the formation of nanosized grains was found in the samples. Using an energy-dispersive X-ray spectroscopy (EDX) device, elemental analysis was performed to detect the presence of different elements and determine their proportions in each sample. The critical temperature was also determined. The results showed that when the sample was exposed to radiation, the highest critical temperature was 114 K. - COLLAPSE
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    27 March 2026

  • Research Paper

    Synthesis and Electrochemical Properties of Zn(Mn2-xFex)O4 Cathode Materials for Hybrid Supercapacitors
    Hyeon-Uk Ko, Sang-Shik Park
    Spinel-structured ZnMn2O4 has attracted considerable attention as a promising material for supercapacitors and other secondary energy storage devices due … + READ MORE
    Spinel-structured ZnMn2O4 has attracted considerable attention as a promising material for supercapacitors and other secondary energy storage devices due to its environmental friendliness, low toxicity, and decent electrochemical performance. However, its practical application is hindered by intrinsic drawbacks such as low electrical conductivity and manganese dissolution from the crystal lattice. In the present study, these limitations are addressed by partially substituting Mn with Fe to form Zn(Mn2-xFex)O4 (where x = 0.4, 0.8, 1.2, or 1.6). This material was synthesized via a hydrothermal method and subsequently fabricated into electrodes for use in hybrid supercapacitor devices. Electrochemical analysis using a three-electrode system revealed that Zn(Mn1.2Fe0.8)O4 has the highest specific capacitance of 374 F/g at a current density of 0.1 A/g, with a b-value of 0.811, thereby indicating a highly capacitive-dominant energy storage mechanism. When applied in a full hybrid supercapacitor device, the system achieved a specific capacitance of 121.44 F/g at 0.1 A/g, and retained 70 % of its capacitance after 1,000 charge-discharge cycles at 1 A/g. These results demonstrate the potential of Zn(Mn2-xFex)O4 as a viable electrode material for high-performance hybrid supercapacitors. - COLLAPSE
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    27 March 2026

  • Research Paper

    Comparison of Bending and Impact Property Related to Flux Cored Arc Welding and Submerged Arc Welding of LT-FH with Respect to Welding Parts of Liquefied Petroleum Gas Tank

    LPG선 탱크 용접부 LT-FH 강재의 FCAW 및 SAW 관련 굽힘 및 충격 물성 비교

    Ki Yeol Lee, Chang Gyu Song, Byung Young Moon

    이기열, 송창규, 문병영

    LT-FH, a low temperature C-Mn steel, was utilized to compare the bending and impact properties of various specimens based on welding method. … + READ MORE
    LT-FH, a low temperature C-Mn steel, was utilized to compare the bending and impact properties of various specimens based on welding method. The property-comparison out of welding method was accompanied by performing bending and impact tests under the standards of the “Classification Society” for manufactured structures for LPG tank applications. In order to acquire the property-comparison on the given test specimens, flux cored arc welding (FCAW) and submerged arc welding (SAW) were utilized to weld the given test pieces. The specimens used for the bending and impact tests were prepared by precise fabrication using both lathe and milling machines. First of all, no cracks were observed on the root part of the bent specimen when the bending test was performed. In addition, when evaluating the effects of impact property related to the weld metal and heat affected zone, the SAW results differed little compared to FCAW. Actually, with respect to SAW, the weld metal showed twice as high impact toughness as the heat affected zone. The results of the impact test confirmed that ductile fracture occurred via microstructural mechanism including lots of dimple microstructures, which means that immediate plastic deformation was produced during the Charpy impact test. - COLLAPSE
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    27 March 2026

  • Research Paper

    Effect of Processing Gas Atmosphere on Electrochromic Performances of Amorphous WO3･H2O Films formed at Low Temperature

    저온에서 형성된 비정질 WO3･H2O 막의 가스 분위기에 따른 전기변색 성능 영향

    Seong-Hoon Kang, Ji Yong Jung, Bon-Ryul Koo

    강성훈, 정지용, 구본율

    Amorphous WO3･H2O films were fabricated via spin-coating of a WOCl4 solution at a low temperature of 80 … + READ MORE
    Amorphous WO3･H2O films were fabricated via spin-coating of a WOCl4 solution at a low temperature of 80 °C, and the influence of gas atmosphere during film formation on electrochromic (EC) performances was systematically investigated. The films prepared under an Ar atmosphere exhibited a relatively porous morphology compared to those formed under air, which showed a more uniform and compact surface structure. These morphological differences significantly affected charge transport and electrochemical behavior. In particular, the films formed under air demonstrated enhanced electrical conductivity and faster ion transport due to the formation of a uniform surface morphology, leading to superior response speed and coloration efficiency. In contrast, films formed in the Ar atmosphere suppressed partial crystallization of WO3, thereby increasing the amorphous WO3･H2O fraction with abundant oxygen bonding sites that act as electrochemically active sites. This characteristic enabled a wider optical modulation during coloration. These results indicate that processing gas-atmosphere-controlled amorphous WO3･H2O films at low-temperature is an effective strategy for improving EC performance and expanding their applicability to flexible devices and energy-efficient smart window technologies. - COLLAPSE
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    27 March 2026

  • Research Paper

    Performance Enhancement of TiO2-Based Capacitors via Plasma-Enhanced Atomic Layer Deposition and Plasma Pre-Treatment

    플라즈마 원자층 증착법과 플라즈마 전처리를 이용한 TiO2 기반 커패시터의 성능 향상

    Si Eun Jung, Su Min Eun, Byung Joon Choi

    정시은, 은수민, 최병준

    As dynamic random-access memory (DRAM) devices continue to scale, reducing the equivalent oxide thickness (EOT) of capacitors and achieving precise control of … + READ MORE
    As dynamic random-access memory (DRAM) devices continue to scale, reducing the equivalent oxide thickness (EOT) of capacitors and achieving precise control of the dielectric-electrode interface have become critical challenges. TiO2 has emerged as a promising high-k dielectric material due to its crystalline phases, anatase (dielectric constant of 30-75) and rutile (dielectric constant of 90-170). However, its application is limited by high leakage current that arises from the low conduction band offset with conventional electrodes. In particular, the low-temperature formation of rutile TiO2 is strongly influenced by lattice mismatch with the bottom electrode. Interface engineering strategies, such as the introduction of RuO2 layers on Ru electrodes, have been proposed to mitigate this issue. In this work, TiN, a bottom electrode widely adopted in mass-production processes, was employed to enhance the electrical performance of TiO2-based capacitors through systematic interface control. The effects of different TiN deposition methods on substrate properties were investigated, and argon plasma treatment was introduced to tailor the dielectric-electrode interface and promote rutile TiO2 formation. Both the TiN bottom electrode and the TiO2 dielectric layer were deposited using plasma-enhanced atomic layer deposition to ensure high film quality. As a result, the leakage current density was suppressed to approximately 10-5 A/cm2 at 0.8 V, while the EOT was reduced to 1.32 nm. These results indicate that the crystallization behavior of TiO2 thin films strongly depends on dielectric thickness and substrate crystallinity. The findings provide important guidelines for developing TiO2-based high-k dielectric thin films for advanced capacitor applications. - COLLAPSE
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    27 March 2026
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