Publications by authors named "Yun Jae Kwon"
We propose and demonstrate an angularly offset multiline (AOML) dispersive silicon nitride optical phased array (OPA) that enables efficient line beam scanning with an expanded field of view (FOV) and plateau envelope. The suggested AOML OPA incorporates multiline OPA units, which were seamlessly integrated with a 45° angular offset through a thermo-optic switch based on a multimode interference coupler, resulting in a wide FOV that combines three consecutive scanning ranges. Simultaneously, a periodic diffraction envelope rendered by the multiline OPA units contributes to reduced peak intensity fluctuation of the main lobe across the large FOV.
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- - This study introduces a new beam-steering device using a solid-state electro-optical phased array (EOPA) that combines thin-film lithium niobate (TFLN) and silicon nitride (SiN) without needing direct TFLN etching.
- - The electro-optic modulator array features cascaded multimode interference couplers with specific performance metrics, including a low power consumption of 3.2 pJ/π and a modulation speed of 1.2 GHz.
- - The EOPA design allows for precise control of near-infrared beams with a field-of-view of 22° by 5°, aiming for efficient, low-power, and high-speed operation in beam steering applications.
A novel contact model is presented to efficiently solve a face-mask contact problem by using the finite element (FE) method for the optimized design of a custom facial mask. Simulation of contact pressure for various mask designs considering material properties of the face allows virtual evaluation of the suitability of a mask design for a person's face without conducting empirical measurement of the face-mask contact pressure. The proposed contact model is accomplished by combining three approaches to reduce the calculation cost of simulating the face-mask contact: (1) use of a simplified and modifiable mask model that applies a spline curve to design points; (2) reduction of the FE model of the face by applying static condensation; and (3) application of a contact assumption that uses the Lagrange multiplier method.
View Article and Find Full Text PDFObjective: To investigate the development of nephrotoxicity associated with colistin dose, and whether this relationship differs depending on renal function.
Design: A retrospective cohort study of patients who received intravenous colistin to treat infections caused by extensively drug-resistant Gram-negative microorganisms. Adult patients receiving colistin for 72 hours or longer were included in this study.