Yonsei University · Engineering
Professor Hyun-Kyu Kim's research lab specializes in the development of advanced simulation techniques for microstructural evolution in materials, particularly using phase-field modeling combined with grain boundary energy databases to study phenomena such as grain growth and phase transformations in metals like bcc iron. In parallel, the lab focuses on integrated photonics and photonic-electronic systems, designing compact, intelligent, and self-calibrating silicon photonic integrated circuits for high-speed optical communication, including WDM receivers, modulators, and optical switch fabrics. The lab emphasizes real-time control systems—implemented via FPGAs and on-chip feedback mechanisms—to maintain optimal performance under environmental fluctuations such as temperature and optical power variations. These interdisciplinary efforts bridge materials science, computational modeling, and integrated photonics for next-generation functional devices.
Figures are computed from collected data and may differ slightly.
A 3D phase-field model for grain growth combined with a grain boundary (GB) energy database is proposed. The phase-field model is applied to a grain growth simulation of polycrystalline bcc Fe to investigate the effect of anisotropic GB energy on the microstructural evolution and its kinetics. It is found that the anisotropy in the GB energy results in different microstructures and slower kinetics, especially when the portion of low-angle, low-energy GBs is large. We discuss the applicability of
Three new prenylated isoflavones, 5,7-dihydroxy-6-(2''-hydroxy-3''-methylbut-3''-enyl)-4'-methoxylisoflavone (1), 5,4'-dihydroxy-6-(3''-methylbut-2''-enyl)-2'''-(4'''-hydroxy-4'''-methylethyl)-3'''-methoxydihydrofurano-[4''',5''';7,8]isoflavone (2), and 5,4'-dihydroxy-8-(3''-methylbut-2''-enyl)-2'''-(4'''-hydroxy-4'''-methylethyl)furano-[4''',5''';6,7]isoflavone (3), a benzylated dihydroflavonol, 5,7,4'-trihydroxy-8-p-hydroxybenzyldihydroflavonol (4), and eight known flavonoids (5-12) were isola
Anti-inflammatory effects of Houttuynia cordata supercritical extract (HSE) were investigated in rat carrageenan-air pouch model. Oral administration of HSE (50-200 mg/kg) suppressed carrageenan-induced exudation and albumin leakage, as well as inflammatory cell infiltration at a high dose (200 mg/kg). Intraperitoneal injection of dexamethasone (2 mg/kg) only decreased exudation and cell infiltration, while indomethacin (2 mg/kg, i.p.) reduced exudate volume and albumin content without influence
We demonstrate a controller that can automatically determine the on-chip heater voltage required for the quadrature bias of the Si photonic Mach-Zehnder Modulator (MZM) and maintain this condition against fluctuations in temperature or the input optical power. The controller is implemented with an FPGA together with monitoring and driving circuits. Its operation is successfully demonstrated with a fabricated Si single-drive push-pull MZM.
Cryptococcus neoformans infections occur most frequently in immunocompromised patients. Here, we report a case of cryptococcal meningitis in a previously immunocompetent 78-year-old female patient after treatment of COVID-19. Underlying diseases included hypertension, hyperlipidemia, and diabetes. The patient was critically ill and was treated with remdesivir, baricitinib, and dexamethasone. During hospitalization, her mental state changed, and C. neoformans was detected in the cerebrospinal flu
We demonstrate an FPGA-based controller for Si MZI-based Spanke-Benes 4 × 4 optical switch fabric that can automatically calibrate each individual switching cell and select the desired routing configuration. In order to minimize the power consumption for optical switching operation, the optimal heater voltages for the cross and the bar state of each switching cell is determined during the calibration. The operation of our controller is successfully verified with a Si MZI-based Spanke-Benes 4 × 4
Paranasal sinus mucoceles are benign diseases that are formed by chronic inflammation, nasal polyps, adhesion after surgery, tumors, trauma etc. that obstruct the paranasal sinus orifices or lesser salivary glands orifices which cause mucous flow to be pooled, causing expansion, focal bone destruction and increase in pressure in the surrounding tissue. Treatment is done by radical therapy by total removal of the polyp or by conservative care by post-op marsupialization and orifice maintenance, t
Hierarchical Body-Centered Cube (HBCC) System designed in this paper is the first experimental system to implement Massively Parallel Processing (MPP) system. HBCC has an additional center node in the interconnection network topology of hypercube to overcome the drawback that the number of edge per node grows as dimension increases. Thus our HBCC topology consists of one center node and eight internal nodes. And using this topology, we have implemented the HBCC experimental system. We developed
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