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Overview of nuclear data production system at RAON
No full textNuclear Data Production System (NDPS), a fast neutron facility for nuclear science and applications, was constructed at the Rare Isotope Accelerator complex for ON-line experiments (RAON) in Korea. NDPS is designed to provide both white and quasi-monoenergetic neutrons using 98 MeV deuteron and 20 - 83 MeV proton beams with thick graphite and thin lithium targets, respectively. Neutron energy is determined by employing the Time-Of-Flight (TOF) technique, along with a pulsed deuteron (or proton) beam with a repetition rate of less than 200 kHz. Fast neutrons are produced in the target room and are guided to the TOF room through a 4 m long neutron collimator consisting of iron and 5% borated polyethylene. The neutron beam is monitored using a parallel plate avalanche counter (PPAC) and a micro-mesh gaseous (MICROMEGAS) detector installed in the TOF room, so as to measure the energy and the position of neutrons
Polythiophene solar cells processed from non-halogenated solvent with 15.68% efficiency
No full textPolythiophenes (PTs) are prospective polymer donors for large-scale manufacturing and industrialization owing to their simple structures and low synthetic cost. However, the fabrication of PT solar cells depends on highly toxic chlorinated solvents, and less research has been done on the use of more environmentally friendly non-halogenated solvents. Herein, highly efficient PT solar cells based on top-performance polythiophene, P5TCN-F25, processed from a non-halogenated solvent are reported by delicate aggregation control. A power conversion efficiency of up to 15.68% was achieved by depositing the active layer from a hot o-xylene solution, which is the record efficiency of non-halogenated processed PT solar cells up to date. The appropriate solution temperature is beneficial to the formation of ordered polymer stacking and desirable phase separation size, which thereby contributes to enhanced charge transfer efficiency, more balanced hole electron mobility, and reduced trap-assisted recombination. These results provide valuable implications for improving the efficiency of PT solar cells via environmentally-friendly processing
Influence of the Lithium-Ion Concentration in Electrolytes on the Performance of Dye-Sensitized Photorechargeable Batteries
No full textDye-sensitized photorechargeable batteries (DSPBs) haverecentlygained attention for realizing energy recycling systems under dimlight conditions. However, their performance under high storage efficiency(i.e., the capacity charged within a limited time) for practical applicationremains to be evaluated. Herein, we varied the lithium (Li)-ion concentration,which plays a dual role as energy charging and storage components,to obtain the optimized energy density of DSPBs. Electrochemical studiesshowed that the Li-ion concentration strongly affected the resistancecharacteristics of DSPBs. In particular, increasing the Li-ion concentrationimproved the output capacity and decreased the output voltage. Consequently,the energy density of the finely optimized DSPB improved from 8.73to 12.64 mWh/cm(3) when irradiated by a 1000-lx indoor light-emitting-diodelamp. These findings on the effects of Li-ion concentrations in electrolyteson the performance of DSPBs represent a step forward in realizingthe practical application of DSPBs
Morphology control of high-quality hexagonal perovskite BaNiO3 by molten salt method
No full textBaNiO3 single crystals with a hexagonal perovskite structure are prized for their exceptional Ni oxidation state and face-sharing structure, which grants them a high-performance potential as electrocatalysts. Despite their potential, obtaining high-quality morphology of BaNiO3 single crystals remains a challenge, making their characterization difficult and limiting their efficiency. In this study, we present a method for synthesizing high-quality BaNiO3 single crystals by morphology control using a molten salt method, which involves modifying the concentration of KOH, reaction time, and cooling rate. The optimal conditions for synthesizing high-quality BaNiO3 single crystals were found to be a reactant-to-KOH ratio of 1:50 and a reaction time of more than 3 h, which resulted in hexagonal-prism-shaped single crystals. However, using different reactant-to-salt ratios and shorter reaction times led to the formation of polycrystalline or pine-needle-shaped BaNiO3 along with secondary phases of BaCO3 and NiO. A higher KOH concentration required a longer reaction time, as the precursor diffusion rate slowed down. The average size of BaNiO3 single crystals increased as the cooling rate decreased, reaching the average width of similar to 90 mm and the length of over 1 mm at the cooling rate of 5 degrees C/h. Our findings present optimal conditions for synthesizing a high-quality single-crystalline BaNiO3 with a hexagonal perovskite structure and could contribute to the development of BaNiO3 crystals for applications in ferroelectrics, photovoltaics, and chemical catalysis. (c) 2023 Elsevier Ltd. All rights reserved
Two-step value normalization accounts for the impacts of choice-unavailability on decision processes: an eye-tracking study
No full textConstruction of Chimeric Metal-Organic Frameworks with Symmetry-Mismatched Building Blocks
No full textEditorial: Materials and processing of emerging non-volatile memory for advanced applications
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No full textDepartment of Mechanical Engineeringclos
Viewpoint-aware Point Cloud Registration for Robust SLAM
No full textDepartment of Mechanical EngineeringSimultaneous localization and mapping (SLAM) utilizes consecutive sensor inputs to compute its movement over time. During this process, errors continue to accumulate at each step. These accumulated errors are a significant challenge for SLAM. The most well-known solution for these accumulated errors is loop closing. Lidar-based SLAM closes the loop by registering two point clouds. However the point cloud registration is easy to fail when there are missing points between two point clouds due to occlusion and partial overlap. To address this problem, here we proposes a viewpoint-aware point cloud registration method that applies weight in the point-to-plane iterative closest point (ICP) algorithm to consider the visibility of source point cloud from the target point cloud viewpoint. The proposed method yields more accurate and robust results than the baseline approaches in the experiments using KITTI dataset.clos
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No full textDepartment of Mechanical Engineeringclos