The phase transition of Li3PO4 solid electrolyte for secondary batteries in vacuum has been studied by using real-time synchrotron X-ray scattering. According to the vacuum heating results, the crystal β-Li3PO4 phase was stable only from room temperature to 400°C. The crystal γ-Li3PO4 phase appeared at 410°C and the crystal β-Li3PO4 phase completely disappeared at 430°C. The transition from the β-Li3PO4 to the γ-Li3PO4 phases occurred primarily at 410°C, which is 40°C lower than the transition temperature of 450°C in air. The decrease in the phase transition temperature in vacuum, compared to that in air, is attributed to a relatively high concentration of oxygen vacancies. As the isothermal annealing time at 390°C was increased to 8 hours, the β-Li3PO4 phase was completely transitioned into the γ-Li3PO4 phase. Our study revealed the detailed transition behavior from the β-Li3PO4 to the γ-Li3PO4 phases during real-time annealing in vacuum.
We have studied the thermal stability of NCM622 cathode material for Li-ion batteries using real-time synchrotron x-ray scattering below 600°C in both air and vacuum. The expansion of the mean particle size, which reached maximum values of 10.3 μm in air and 10.6 μm in vacuum at 200°C, was attributed to the dehydration of intergranular water within the NCM622 powders. Across all annealing temperatures, the amount of crystal NCM622 phase in air was consistently higher than that in vacuum. The crystal domain sizes in air showed less variation than that in vacuum during annealing from RT to 500°C. These indicate that the crystal NCM622 phase is more thermally stable during annealing in air than in vacuum. This stability is attributed to the presence of 21% oxygen in air, which is absent under vacuum conditions.
Hazardous gas leakage incidents rank among the most serious safety accidents, leading to significant loss of life, extensive property damage, and severe environmental pollution. This paper describes an innovative IoT-based Assembly Double Pipe System (IADPS) designed for the prevention, early detection, and automated isolation of toxic gas leaks. The proposed system features a double-layered pipe design, with nitrogen charged between the inner and outer pipes, and gas detectors installed at strategic locations. This configuration is intended to prevent pipe corrosion, suppress ignition caused by escaping gas, and facilitate the early detection of gas leaks, thereby mitigating the risk of safety accidents. Furthermore, the system includes a comprehensive real-time monitoring system for pipe integrity and gas leakage, as well as an automated gas leakage detection and isolation system to quickly respond to any incidents.
In-situ analyzation and detection of real-time chemical reactions can be a significant part in interpreting the underlying mechanism in very reactive chemical reactions. To do this, first we have designed a microfluidic device (MFD) pattern for observation of synthesis of hierarchical nanostructures based on graphene oxide (GO), conjugating the well-known coupling reaction by which the solution of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling is enhanced in the presence of n-hydroxysuccinimide (NHS) to make amide bonding, hereafter called as the EDC coupling. Then, we have manufactured microfluidic devices with multiple tens of micrometer-sized channels that can circulate those nanomaterials to be chemically reacted in the channels. These microfluidic devices were made by negative photo lithography and soft lithography. We showed the possibility of using Raman spectroscopy to reveal the basic mechanism of the energy storage applications.
In this paper, laser-induced fluorescence properties of four plastics were characterized through spectrometer analysis for real-time microplastic counting. Recently, environmental problems related to microplastics have emerged. In order to detect microplastics, analysis methods such as FT-IR and Raman are used. However, they have the disadvantages of being timeconsuming and requiring a pretreatment process. In most plastic products on the market, 10% to 30% of plasticizers and reinforcing agents are added. Therefore, most microplastics present in seawater and freshwater emit fluorescence signals by 270 nm UV light source regardless of their type due to their molecular structure due to additives. Real-time microplastics counting is possible more easily by using the proposed laser-induced fluorescence detection method because of the fluorescence expression characteristic of 340 nm that appears due to the plasticizer of plastics.
Compared to conventional pure-tone audiometer (PTA), the computerized one has several advantages such as relatively lower price, better flexibility, and easy operation. In addition, the computerized PTA can be easily extended to support automatic calibration. In this study, the support of automatic calibration in the computerized PTA has been addressed using the Linux realtime spectrum analyzer and network. In terms of accuracy, the new automatic calibration machine was compared to the existing manually operated one. According to the comparison, normal operation and high accuracy were observed within the scope of the international standard.
Currently in Korea, the simple catenary type overhead contact line system is being applied to both conventional lines and high speed lines of electric railway, and circulation current flowing into the catenary system frequently bring undesirable consequences. Namely, the connector wire has many problems according to a flow of excessive circulation current and arc current on catenary when an electric train runs at high speed. This paper presents the development and application of a real-time data acquisition system designed to measure the electrical characteristics of an overhead catenary system in electric railways. The developed system is capable of storing data of a 25 kV power source in a live wire state through a telemetry environment. The field test results show that the proposed technique and the developed system can be practically applied to measure characteristics of current of an overhead catenary system.
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On the Implementation of an Advanced Judgement Algorithm for Contact Loss of Catenary System Young Park, Ho-Sung Jung, Il-Kwon Yun, Wonha Kim The Transactions of The Korean Institute of Electrical Engineers.2014; 63(6): 850. CrossRef
Utilizing Technology in Measurement System for Catenary Current: - Focusing on Testing Results for Kyoungbu High-speed Line in Korea - Young Park, Hosung Jung, Kiwon Lee The Transactions of The Korean Institute of Electrical Engineers.2013; 62(10): 1465. CrossRef
Video Image Analysis in Accordance with Power Density of Arcing for Current Collection System in Electric Railway Young Park, Kiwon Lee, Chulmin Park, Jae-Kwang Kim, Ahram Jeon, Sam-Young Kwon, Yong Hyun Cho The Transactions of The Korean Institute of Electrical Engineers.2013; 62(9): 1343. CrossRef
A Experimental Study on Train Speed and Wave Propagation Speed of Contact Wire according to the Speed-up Kiwon Lee The Transactions of The Korean Institute of Electrical Engineers.2013; 62(12): 1820. CrossRef
Implementation of Optimization of the Uplift Amount Measurement System of Overhead Contact Line Young Park, Kiwon Lee, Chulmin Park, Sam-Young Kwon The Transactions of The Korean Institute of Electrical Engineers.2013; 62(6): 886. CrossRef
Utilizing Technology in Measurement System for Catenary Current: - Focusing on Testing Results for Kyoungbu High-speed Line in Korea - Young Park, Hosung Jung, Kiwon Lee The Transactions of The Korean Institute of Electrical Engineers.2013; 62(10): 1465. CrossRef
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