https://scholar.dgist.ac.kr/handle/20.500.11750/10154 2026-04-25T17:06:05Z 2026-04-25T17:06:05Z Choi, Jae Sung Kang, Won Seok Son, Chan Sik Son, Byung Rak Lee, Dong Ha https://scholar.dgist.ac.kr/handle/20.500.11750/60268 2026-04-15T08:16:13Z 2014-12-31T15:00:00Z

Title: Tag interference based mobile object tracking with passive UHF RFID system Author(s): Choi, Jae Sung; Kang, Won Seok; Son, Chan Sik; Son, Byung Rak; Lee, Dong Ha Abstract: This paper proposes a novel method that enables location sensing for a mobile object by utilizing deployed passive UHF Radio Frequency Identification (RFID) tags and a stationary RFID reader. In order to estimate the mobile object location, the proposed method utilizes the second order under damped system based tag to tag interference model. The empirical study using RFID systems and a mobile robot verifies the effectiveness and performance of the proposed method. © Springer-Verlag Berlin Heidelberg 2015.

2014-12-31T15:00:00Z Jamal, Hasan Khan, Firoz Kim, Suin Alzahrani, Atif Kim, Jae Hyun https://scholar.dgist.ac.kr/handle/20.500.11750/60226 2026-04-15T08:10:57Z 2025-12-31T15:00:00Z

Title: Interface-Stabilized and Fire-Resistant Composite Polymer Electrolyte for Safe and Durable All-Solid-State Lithium Batteries Author(s): Jamal, Hasan; Khan, Firoz; Kim, Suin; Alzahrani, Atif; Kim, Jae Hyun Abstract: The multifaceted composition of the solid electrolyte interface (SEI), the low Li-ion conductivity, and the fire hazard sensitivity of poly(ethylene oxide) (PEO)-based solid-state-electrolytes (SSEs) restrict them from being used in cutting-edge all-solid-state lithium-metal batteries (SS-LMBs). Here, a multifunctional solid composite polymer electrolyte (SMB-CPE) was developed by using silica mesoball fillers, offering simultaneous improvements in ionic transport, interfacial stability, and thermal protection. The presence of fillers enabled the segmental motion of the polymer chains, thereby reducing the activation energy for Li-ion diffusion and empowering more efficient Li-ion transportation that exhibited Li-ion conductivity of 6.37 x 10(-3) S cm(-1) at 60 degrees C. Furthermore, the critical current density dramatically doubled it when compared to the unfilled system. Notably, the symmetric [Li/SMB-CPE/Li] cell showed excellent galvanostatic Li plating and stripping, exhibiting stability for 2000 h at 200 mu A cm(-2). However, full-cell configurations with LiFePO4 delivered an initial discharge capacity of similar to 150 mAh g(-1) at 1 C and retained 81.5% capacity after 1000 cycles. Moreover, postcombustion studies reveal that the filler enhanced carbonization and suppressed the formation of hazardous byproducts. The formation of C-O, C=O, CF3, LiF, and high-oxidation-state sulfur and nitrogen species was significantly lessened, suggesting mitigation of exothermic and toxic degradation pathways.

2025-12-31T15:00:00Z Kim, Young Kwang Seo, Hye-Jin Hong, Seong Hui Lee, Chang-Hun Choi, Ik Sung Song, Hyun Woo Lim, Sang Kyoo https://scholar.dgist.ac.kr/handle/20.500.11750/60206 2026-04-15T08:10:37Z 2026-02-28T15:00:00Z

Title: Key Determinants of Hydrolytic Stability of PLA/PBS Blend Fibers: The Role of Aromatic Sulfonate Derivative and Carbodiimide Author(s): Kim, Young Kwang; Seo, Hye-Jin; Hong, Seong Hui; Lee, Chang-Hun; Choi, Ik Sung; Song, Hyun Woo; Lim, Sang Kyoo Abstract: The hydrolytic stability of poly (lactic acid) (PLA)/poly (butylene succinate) (PBS) blend fibers was systematically investigated by incorporating an aromatic sulfonate derivative (nucleating agent, N) and carbodiimide (anti-hydrolysis agent, Anti-H). Neat PLA/PBS blend fibers (3 wt% PBS) retained only ∼53.9% of their initial tensile strength after hydrolysis, whereas fibers containing both the nucleating agent (N) and anti-hydrolysis agent (Anti-H) preserved up to 97.2% of their initial strength. DSC and 2D-WAXD analyses showed that N selectively promoted the development and retention of the PLA (203) crystalline reflection, accompanied by enhanced crystallinity and molecular orientation along the PLA (200)/(110) planes. 1D-WAXD demonstrated that the intensity ratio of PLA (203) to PLA (200)/(110) reflections correlates with hydrolytic retention following a Boltzmann-type sigmoidal relationship, with a critical threshold x0 ≈ 0.227. Time-dependent FTIR and XPS analyses demonstrated that Anti-H effectively capped the terminal –COOH groups, suppressing autocatalytic chain scission and providing complementary chemical stabilization. Hydrolysis decreased –COOH and –Cdouble bondO functional groups, while the H-bonded –OH increased. Correlation analysis indicated that changes in –Cdouble bondO most strongly influenced tensile retention. SEM observations revealed smooth fiber surfaces with no discernible defects or phase separation, as well as minimal morphological and compositional changes in the optimized fibers after hydrolysis. Collectively, these results demonstrate that the exceptional hydrolytic durability of PLA/PBS blend fibers arises from the synergistic interplay of selective (203) crystalline coherence, preserved molecular orientation, and chemical end-group stabilization.

2026-02-28T15:00:00Z Hoang, Van-Quy Lee, Jaebaek Kadiri-English, Bashiru Cho, Eunkyung Ali, Amanat Kumar, Naveen Gilshtein, Evgeniia Canulescu, Stela Son, Dae-Ho Yoo, Hyesun Huy, Vo Pham Hoang Le-van, Quynh Hwang, Dae-Kue Kang, Jin-Kyu Yang, Kee-Jeong Sung, Shi-Joon Kim, Dae-Hwan https://scholar.dgist.ac.kr/handle/20.500.11750/60195 2026-04-15T18:01:40Z

Title: Ag-Induced Phase and Defect Engineering of Co-Evaporated Sb2Se3 Thin Films for Enhanced Photovoltaic Performance Author(s): Hoang, Van-Quy; Lee, Jaebaek; Kadiri-English, Bashiru; Cho, Eunkyung; Ali, Amanat; Kumar, Naveen; Gilshtein, Evgeniia; Canulescu, Stela; Son, Dae-Ho; Yoo, Hyesun; Huy, Vo Pham Hoang; Le-van, Quynh; Hwang, Dae-Kue; Kang, Jin-Kyu; Yang, Kee-Jeong; Sung, Shi-Joon; Kim, Dae-Hwan Abstract: High-efficiency antimony selenide (Sb2Se3) solar cells remain limited by anisotropic charge transport, high defect density, and rapid back-contact recombination. We demonstrate a simple co-evaporation strategy for introducing an ultrathin Ag interlayer at the Sb2Se3/Mo interface. The proposed strategy significantly enhances the performance of the fabricated devices. Incorporation of an Ag layer promotes grain growth, improves crystallinity, and passivates bulk defects, thereby suppressing interfacial recombination and enhancing both the open-circuit voltage and fill factor. Structural analyses reveal an orientation transition of the quasi-one-dimensional orthorhombic Sb2Se3 ribbons from a preferred (hk1) orientation to a random one. This transition is driven by the sequential reaction of Ag with Se to form Ag2Se, which subsequently reacts with Sb2Se3 to yield AgSbSe2. However, when the Ag content exceeds the optimal level, unreacted Ag2Se accumulates at the bottom of the film, degrading device performance. Time-resolved photoluminescence and capacitance measurements confirm reduced defect densities and optimized junction properties. The optimized Sb2Se3 device incorporating the Ag interlayer achieves a power conversion efficiency of 5.56%, outperforming the Ag-free counterpart under standard AM 1.5G illumination. The proposed strategy offers a promising route to high-performance Sb2Se3 thin-film photovoltaics and provides a pathway for tandem integration of Sb2Se3-based devices.