In this study, the physical and optical properties of ZnS:Mn2+ Quantum Dot prepared by wet-process condition with Mn/Zn ratio was valuated. The powder characteristics and optical behavior were investigated through XRD, TEM and Photo spectrometer exicted by various UV light source. We found the main peak of ZnS (111) was shifted by 0.8 degree to low angle position with increasing stirring energy from 200 RPM to 600 RPM, which is thought to be the increase of lattice defects during wet process. The photo luminescence at 600 RPM shows also higher blue intensity which is well correlated with XRD results. With increasing Mn/Zn ratio, the PL intensity become higher and shifed by 8.5nm to right side, by the increment of substitutional Mn2+ ions.
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Study on the Effect of Solvent for Dispersing Precursor in DSA Production for Ammonia Oxidation Darae Jeon, Daewon Pak Journal of Korean Society of Environmental Engineers.2022; 44(9): 336. CrossRef
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This paper dealt with the radiated electromagnetic wave detection of partial discharge (PD) in oil for insulation diagnostics of oil-immersed transformers. Three types of electrode system were fabricated to simulate the insulation defects that could occur in oil-immersed transformers. Frequency components of radiated electromagnetic wave in oil was measured by broadband bi-conical antennas of 300 MHz∼2 GHz and a spectrum analyzer of 9 kHz∼3 GHz. Frequency component of electromagnetic waves from PD in oil were highly distributed at 500 MHz. From the result, a narrow-band monopole antenna with the center frequency of 500 MHz was fabricated. We could detect PD signal in insulation oil without an influence of external noise by a measurement system which consists of the prototype monopole antenna, a LNA (Low Noise Amplifier), an oscilloscope and a spectrum analyzer.
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A Study on the Operation Characteristics of Arc Fault Detection Device under Arc Generation Heejun Kwon, SungHwan Kim, Jihee Lee, Kiseok Kim, Haiyoung Jung International Journal of Fire Science and Engineering.2024; 38(2): 27. CrossRef
Highly Sensitive Partial Discharge Sensor with Remote Monitoring Capabilities Kyoo-Nam Choi The Journal of the Korea institute of electronic communication sciences.2015; 10(3): 349. CrossRef
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