• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1323-1337
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• 2020

GEO-KOMPSAT-2A AMI (Advanced Meteorological Imager) radiometric calibration evaluation is an essential element not only for functional and performance verification of the payload but for the quality of the sensor data. AMI instrument consists of six reflective channels and ten thermal infrared ones. One of the key parameters representing radiometric properties of the sensor is a SNR (Signal-to-Noise Ratio) for the reflective channels and a NEdT (Noise Equivalent delta Temperature) for the IR ones respectively. Other important radiometric calibration parameters are a dynamic range and a gain value related with the responsivity of detectors. To verify major radiometric calibration performance of AMI, an offline radiometric evaluation tool was developed separately with a real-time AMI data processing system. Using the evaluation tool, validation activities were carried out during the GEO-KOMPSAT-2A In-Orbit Test period. The results from the evaluation tool were cross checked with those of the HARRIS, which is the AMI payload vendor. AMI radiometric evaluation activities were conducted through three phases for both sides (Side 1 and Side 2) of AMI payload. Results showed that performances of the key radiometric properties were outstanding with respect to the radiometric requirements of the payload. The effectiveness of the evaluation tool was verified as well.

• Korean Journal of Remote Sensing
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• v.38 no.6_4
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• pp.1955-1969
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• 2022

Most of the public and private users who use national satellite information such as the KOMPSAT series mainly use Electro-Optical and Infrared (EO/IR) satellite images, and the utilization of Synthetic Aperture Radar (SAR) images is relatively insufficient. As KOMPSAT-5 currently in operation, KOMPSAT-6 and micro SAR satellite constellation systems are scheduled to be launched in the future, the demand for utilization of SAR satellite information is increasing in various fields. Accordingly, it is necessary to possess core technology for SAR utilization that can support the utilization of SAR satellite information for users. Due to the all-weather properties of SAR system, change detection technology is a key application technology. However, until now, the development of technology that automatic change detection and cueing using SAR images is insufficient. Through this study, the requirements of automatic change detection and cueing function using multi-temporal KOMPSAT-5 SAR satellite images were derived and a prototype program was developed. This prototype program aims to secure independent SAR utilization technology and promote the utilization of domestic SAR satellite information by practitioners in public sector organizations in Korea.

• Membrane Journal
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• v.32 no.6
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• pp.486-495
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• 2022

This study presents the improved recovery efficiency of rare metal ions through the modified separation membrane wettability and hydrogen ion permeation in the anion exchange membrane (AEM) under the recovery process of combined electrodialysis and solvent extraction. Specifically, the wettability of the separator was enhanced by hydrophilic modification on one separator surface through polydopamine (PDA) and lipophilic modification on the other surface through SiO₂ or graphene oxide (GO). In addition, the modified surface of AEM with polyethyleneimine (PEI), PDA, poly(vinylidene fluoride) (PVDF), etc. reduces the water uptake and modify the pore structure for proton ions generation. The suppressed transport resulted in the reduced hydrogen ion permeation. In the characterization, the surface morphology, chemical properties and composition of membrane or AEM were analyzed with Scanning Electron Microscopy (SEM) and Fourier Transform-Infrared Spectroscopy (FT-IR). Based on the analyses, improved extraction and stripping and hydrogen ion transport inhibition were demonstrated for the copper ion recovery system.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4102-4110
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• 2022

Aiming at high-power and long-pulse operation up to 1000 s, some improvements have been made for both 2.45 GHz and 4.6 GHz lower hybrid (LH) systems during the recent 5 years. At first, the guard limiters of the LH antennas with graphite tiles were upgraded to tungsten, the most promising material for plasma facing components in nuclear fusion devices. These new guard limiters can operate at a peak power density of 12.9 MW/m². Strong hot spots were usually observed on the old graphite limiters when 4.6 GHz system operated with power >2.0 MW [B. N. Wan et al., Nucl. Fusion 57 (2017) 102019], leading to a reduction of the maximum power capability. With the new limiters, 4.6 GHz LH system, the main current drive (CD) and electron heating tool for EAST, can be operated with power >2.5 MW routinely. Long-pulse operation up to 100 s with 4.6 GHz LH power of 2.4 MW was achieved in 2021 and the maximal temperature on the guard limiters measured by an infrared (IR) camera was about 540 ℃, much below the permissible value of tungsten material (~1200 ℃). A discharge with a duration of 1056 s was achieved and the 4.6 GHz LH energy injected into the plasma was up to 1.05 GJ. Secondly, the fully-active-multijunction (FAM) launcher of 2.45 GHz system was upgraded to a passive-active-multijunction (PAM), for which the density of optimum coupling was relatively low (below the cut-off value). Good coupling with reflection coefficient ~3% has been achieved with plasma-antenna distance up to 11 cm for the new PAM. Finally, in order to eliminate the effect of ion cyclotron range of frequencies (ICRF) wave on 4.6 GHz LH wave coupling, the location of the ICRF launcher was changed to a port that is located 157.5° toroidally from the 4.6 GHz LH system and is not magnetically connected.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.7-11
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• 2022

Recently, Hanmi Gemological Institute & Laboratory (HGI) had an opportunity to examine 5 transparent synthetic moissanite. The round brilliants ranged from 0.93 to 0.96 ct and had a colorless, pink, yellow, blue, and red color. Advanced testing results, including Fourier-transform infrared (FTIR) and Raman spectroscopy, identified all the specimens as synthetic moissanite. Under the microscope, all samples except the colorless were confirmed to be a synthetic moissanite coated with a colored film. EDXRF chemical analysis detected very weak X-ray fluorescence peak characteristics of Ca, Ti, and Co in the colored samples. These features were not detected in the colorless sample. Raman spectroscopy investigation was unable to detect the 1332 cm^-1 (produced by sp³ bonding of carbon atoms) or the ~1550 cm^-1 (produced by graphite-related sp² bonding) peak in the colorless sample. The SEM image of the colorless sample showed no indication of a coating. The TEM image of the colorless sample revealed the presence of a 3~8 nm thick layer on the moissanite. Moreover, from the corresponding STEM Z-contrast image combined with the energy-dispersive X-ray spectroscopy (EDX) line profiles and EDX elemental maps, this layer was estimated to be carbon, silicon and oxygen.

• Composites Research
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• v.37 no.3
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• pp.204-208
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• 2024

De-icing/anti-icing fluid is essential for removing ice formation on aircraft. It chemically removes ice using organic solvents, which can cause damage to the topcoat surface in the process. In this study, glycol-based deicing/anti-icing fluid was used to remove ice, and the resulting damage to the topcoat was examined. USB microscope was used to observe the formation and growth of ice, while a confocal microscope was employed to observe the surface morphology after treatment with de-icing/anti-icing fluid. Additionally, coating thickness measurements and Fourier transform infrared (FT-IR) analysis were conducted to investigate the physical and chemical changes on the surface. The repeated application of de-icing/anti-icing fluid showed a reduction in the ice formation rate and an increase in the growth rate. Damage during the pressurization process and surface damage to the polyurethane topcoat caused by ethylene glycol were observed during the de-icing process. Although no chemical changes were detected, the analysis revealed that surface uniformity decreased, with physical damage such as cracks and undulations forming on the surface. It was confirmed that while de-icing/anti-icing fluid is effective in removing ice, it also causes surface damage.

• Journal of Microbiology and Biotechnology
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• v.34 no.2
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• pp.457-466
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• 2024

Cellobiose dehydrogenases (CDHs) are a group of enzymes belonging to the hemoflavoenzyme group, which are mostly found in fungi. They play an important role in the production of acid sugar. In this research, CDH annotated from the actinobacterium Cellulomonas palmilytica EW123 (CpCDH) was cloned and characterized. The CpCDH exhibited a domain architecture resembling class-I CDH found in Basidiomycota. The cytochrome c and flavin-containing dehydrogenase domains in CpCDH showed an extra-long evolutionary distance compared to fungal CDH. The amino acid sequence of CpCDH revealed conservative catalytic amino acids and a distinct flavin adenine dinucleotide region specific to CDH, setting it apart from closely related sequences. The physicochemical properties of CpCDH displayed optimal pH conditions similar to those of CDHs but differed in terms of optimal temperature. The CpCDH displayed excellent enzymatic activity at low temperatures (below 30℃), unlike other CDHs. Moreover, CpCDH showed the highest substrate specificity for disaccharides such as cellobiose and lactose, which contain a glucose molecule at the non-reducing end. The catalytic efficiency of CpCDH for cellobiose and lactose were 2.05 × 10⁵ and 9.06 × 10⁴ (M^-1 s^-1), respectively. The result from the Fourier-transform infrared spectroscopy (FT-IR) spectra confirmed the presence of cellobionic and lactobionic acids as the oxidative products of CpCDH. This study establishes CpCDH as a novel and attractive bacterial CDH, representing the first report of its kind in the Cellulomonas genus.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.4
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• pp.211-219
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• 2006

The UET(ultrasound excited thermography) for the ,eat-time diagnostics of the object employs an infrared camera to image defects of the surface and subsurface which are locally heated using high-frequency putted ultrasonic excitation. The dissipation of high-power ultrasonic energy around the feces of the defects causes an increase In temperature. The defect's image appears as a hot spot (bright IR source) within a dark background field. The UET for nondestructive diagnostic and evaluation is based on the image analysis of the hot spot as a local response to ultrasonic excited heat deposition. In this paper the applicability of VET for fast imaging of defect is described. The ultrasonic energy is injected into the sample through a transducer in the vertical and horizontal directions respectively. The voltage applied to the transducer is measured by digital oscilloscope, and the waveform are compared. Measurements were performed on four kinds of materials: SUS fatigue crack specimen(thickness 14mm), PCB plate(1.8 mm), CFRP plate(3 mm) and Inconel 600 plate (1 mm). A high power ultrasonic energy with pulse durations of 250ms Is injected into the samples in the horizontal and vertical directions respectively The obtained experimental result reveals that the dissipation loss of the ultrasonic energy In the vertical injection is less than that in the horizontal direction. In the cafe or PCB, CFRP, the size of hot spot in the vortical injection if larger than that in horizontal direction. Duration time of the hot spot in the vertical direction is three times as long as that in the horizontal direction. In the case of Inconel 600 plate and SUS sample, the hot spot in the horizontal injection was detected faster than that in the vertical direction

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.378-384
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• 2018

$C_9H_7NHCrO_3Cl$ was synthesized by reacting $C_9H_7NH$ with chromium (VI) trioxide. The structure of the product was characterized by FT-IR (Fourier transform infrared) spectroscopy and elemental analysis. The oxidation of benzyl alcohol by $C_9H_7NHCrO_3Cl$ in various solvents showed that the reactivity increased with increasing dielectric constant(${\varepsilon}$) in the following order: DMF (N,N'-dimethylformamide) > acetone > chloroform > cyclohexane. The oxidation of alcohols was examined by $C_9H_7NHCrO_3Cl$ in DMF. As a result, $C_9H_7NHCrO_3Cl$ was found to be an efficient oxidizing agent that converts benzyl alcohol, allyl alcohol, primary alcohols, and secondary alcohols to the corresponding aldehydes or ketones (75%-95%). The selective oxidation of alcohols was also examined by $C_9H_7NHCrO_3Cl$ in DMF. $C_9H_7NHCrO_3Cl$ was the selective oxidizing agent of benzyl, allyl and primary alcohol in the presence of secondary ones. In the presence of DMF with an acidic catalyst, such as $H_2SO_4$, $C_9H_7NHCrO_3Cl$ oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, and $m-NO_2$). Electron donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. The Hammett reaction constant (${\rho}$) was -0.69 (308K). The observed experimental data were used to rationalize hydride ion transfer in the rate-determining step.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.325-331
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• 2015

Skin is exposed to sunlight or artificial indoor light on a daily. The reached solar light on the earth surface consist of 50% visible light and 45% infrared (IR) except for ultra violet (UV). The negative effects of UV including UVB and UVA have been steadily investigated within the last decades. However, little is known about the effects of visible or IR light. In this study, we irradiated human dermal fibroblasts using light emitting diode (LED) to investigate the optimal parameter for enhancing cell growth and collagen synthesis. We found that red of 630 nm and green of 520 nm enhance the cell proliferation, but irradiation with purple and blue light exerts toxic effects. To examine the response of irradiation time and light intensity on the fibroblasts, cells were exposed to red or green light with intensities from 0.05 to $0.75mW/cm^2$. Procollagen secretion was increased of 1.4 fold by 10 min irradiation, while 30 min treatment decreased the collagen synthesis of dermal fibroblasts. Treatment with red of $0.3mW/cm^2$ and green of 0.15 and $0.3mW/cm^2$ resulted in enhancement of collagen mRNA. Lastly, we investigated the combinatorial effect of red and green light on dermal fibroblasts. The sequential irradiation of red and green light is an efficient way for the purpose of the increase in the number of fibroblasts than single light treatment. On the other hand, the exposure of red light alone was more effective method for enhancing of collagen secretion. Our study showed that specific light parameters accelerated cell proliferation, gene expression and collagen secretion on human dermal fibroblasts. In conclusion, we demonstrate that light exposure with specific parameter has beneficial effects on the function of dermal fibroblasts, and suggests the possibility of its cosmetically and clinical application.