• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.196-203
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• 2015

BACKGROUND: Purpose of this research is HPLC analysis method development of lycopene in tomato. And then, three components of carotenoid in four kinds of tomatoes (general tomato, cherry tomato, red and orange date tomato) were compared with each other. METHODS AND RESULTS: Lycopene in tomato was extracted with hexane likes other carotenoid components using 500 mg of dried powder sample. HPLC analysis conditions were column temperature ($40^{\circ}C$), detection wavelength (454 nm), flow rate (1.0 mL/min) and injection volume ($20.0{\mu}L$). Lycopene was analyzed by the gradient elution ($60{\rightarrow}100%$) of the mobile phase solvents A[water: methanol=25: 75 (v/v)] and B[ethyl acetate]. CONCLUSION: Three components of carotenoids (lutein, ${\beta}$-carotene, lycopene) were observed in tomatoes. The total carotenoid contents was the highest in red date tomato (662.0 mg/kg dry wt.) and the lowest in orange date tomato (111.3 mg/kg dry wt.). Lycopene contents in tomatoes was the highest percentage (93%) among all the carotenoids.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.188-189
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• 2007

The etching characteristics of $Al_2O_3$ films using the inductively coupled plasma (ICP) was investigated. The etch gas was the mixture of $BCl_3$ and He. The effect of ICP source and bias powers on etch rate and etch selectivity to polycrystalline Si was investigated in the etch process of $Al_2O_3$. The etch rate of $Al_2O_3$ film was 23nm/min when the source power and bias power were 600W and 60W, respectively. The results also indicated that the etch selectivity to polycrystalline Si could not be enhanced to be higher than 1.0 by changing the ICP source power and bias power, under the experimental conditions used in the present work. Based on plasma parameters extracted from Langmuir probe data, the etching mechanism of $Al_2O_3$ film was discussed in detail.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.932-938
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• 2007

The structural, optical, and electrical properties of ZnO thin films grown on glass by radio-frequency (rf) magnetron sputtering were investigated. The mixture flow ratio of $O_2$ to Ar, which was operated with sputtering gas, was chosen as a parameter for growing high-qualify ZnO thin films. The structural properties and surface morphologies of the thin films were characterized by the X-ray diffraction and the atomic force microscope, respectively. As for the optical properties of the films, the optical absorbance was measured in the wavelength range of 300-1100 nm by using UV-VIS spectrophotometer. The optical transmittance, absorption coefficient, and optical bandgap energy of ZnO thin films were calculated from the measured data. The crystallinity of the films was improved and the bandgap energy was increased from 3.08 eV to 3.23 eV as the oxygen flow ratio was increased from 0 % to 50 %. Furthermore, The ultraviolet and violet luminescences were observed by using photoluminescence spectroscopy. The hall mobility was decreased with the increase of oxygen flow ratio.

• Korean Journal of Medicinal Crop Science
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• v.18 no.5
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• pp.311-314
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• 2010

The content of luteolin in the different parts of Lithospermum erythrorhizon was determined by high performance liquid chromatography (HPLC). Luteolin was quantified by a reverse-phase column with gradient solvent program (water : ACN = 90 : 10 to 77 : 23 for 60 min). UV detection was conducted at 330 nm. The content of luteolin was measured in the seeds (0.28 mg/g), stems (0.30 mg/g), and roots (0.16 mg/g) of L. erythrorhizon. The presence of luteolin in Lithospermum species is important in agricultural crop production for increasing the amounts of clinically available medicine and health supplements.

• Journal of Welding and Joining
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• v.23 no.5
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• pp.61-68
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• 2005

Dissimilar joining of Al 6013-T4 alloys and austenite stainless steel was carried out using friction stir welding technique. Microstructures near the weld zone and mechanical properties of the joint have been investigated. Microstructures in the stainless steel side were composed of the heat affected zone and the plastically deformed zone, while those in the Al alloy side were composed of the recrystallized zone including stainless steel particles, the thermo-mechanically affected zone and the heat affected zone. TEM micrographs revealed that the interface region was composed of the mixed layers of elongated stainless steel and ultra-fine grained Al alloy with lamella structure and intermetallic compound layer. Thickness of the intermetallic layer was approximately 300nm and was identified as the A14Fe with hexagonal close packed structure. Mechanical properties, such as tensile and fatigue strengths were lower than those of 6013 Al alloy base metal, because tool inserting location was deviated to Al alloy from the butt line, which resulted in the lack of the stirring.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.12-23
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• 2021

This paper proposes a low power radio frequency receiver front-end where, in a single stage, single-balanced mixer and voltage-controlled oscillator are stacked on top of low noise amplifier and re-use the dc current to reduce the power consumption. In the proposed topology, the voltage-controlled oscillator itself plays the dual role of oscillator and mixer by exploiting a series inductor-capacitor network. Using a 65 nm complementary metal oxide semiconductor technology, the proposed radio frequency front-end is designed and simulated. Oscillating at around 2.4 GHz frequency band, the voltage-controlled oscillator of the proposed radio frequency front-end achieves the phase noise of -72 dBc/Hz, -93 dBc/Hz, and -113 dBc/Hz at 10KHz, 100KHz, and 1 MHz offset frequency, respectively. The simulated voltage conversion gain is about 25 dB. The double-side band noise figure is -14.2 dB, -8.8 dB, and -7.3 dB at 100 KHz, 1 MHz and 10 MHz offset. The radio frequency front-end consumes only 96 ㎼ dc power from a 1-V supply.

• Korean Journal of Applied Biomechanics
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• v.31 no.1
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• pp.64-71
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• 2021

Objective: This study investigated the different in isokinetic peak strength of the knee joint, and kinetics and kinematics in drop landing pattern of lower limb between the patellofemoral pain syndrome (PFPS) patients and normal. Method: 30 adult females were divided into the PFPS (age: 23.13±2.77 yrs; height: 160.97±3.79 cm, weight: 51.19±4.86 kg) and normal group (age: 22.80±2.54 yrs, height: 164.40±5.77 cm, weight: 56.14±8.16 kg), with 15 subjects in each group. To examine the knee isokinetic peak strength, kinematics and kinetics in peak vertical ground reaction force during drop landing. Results: The knee peak torque (Nm) and relative strength (%) were significantly weaker PFPS group than normal group. In addition, PFPS group had significantly greater hip flexion angle (°) than normal group. Moreover, normal group had significantly greater moment of hip abduction, hip internal rotation, and left ankle eversion than PFPS group, and PFPS group had significantly greater moment of knee internal rotation. Finally, there was significant differences between the groups at anteroposterior center of pressure. Conclusion: The PFPS patients had weakened knee strength, and which can result in an unstable landing pattern and cause of more stress in the knee joints despite to effort of reduce vertical ground reaction force.

• Korean Journal of Materials Research
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• v.31 no.11
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• pp.635-641
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• 2021

Cr thin films with O added are deposited on sapphire substrate by DC sputtering and are nitrided in NH₃ atmosphere between 300 and 900 ℃ for various times. X-ray diffraction results show that nitridation begins at 500 ℃, forming CrN and Cr₂N. Cr oxides of Cr₂O₃ are formed at 600 ℃. And, at temperatures higher than 900 ℃, the intermediate materials of Cr₂N and Cr₂O₃ disappear and CrN is dominant. The atomic concentration ratios of Cr and O are 77% and 23%, respectively, over the entire thickness of as-deposited Cr thin film. In the sample nitrided at 600 ℃, a CrN layer in which O is substituted with N is formed from the surface to 90 nm, and the concentrations of Cr and N in the layer are 60% and 40%, respectively. For this reason, CrN and Cr₂N are distributed in the CrN region, where O is substituted with N by nitridation, and Cr oxynitrides are formed in the region below this. The nitridation process is controlled by inter-diffusion of O and N and the parabolic growth law, with activation energy of 0.69 eV.

• Advances in nano research
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• v.13 no.5
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• pp.475-485
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• 2022

Crystalline silicon photovoltaic cells have advantages of zero pollution, large scale and high reliability. A major challenge is that sunlight wavelength with photon energy lower than semiconductor band gap is converted into heat and increase its temperature and reduce its conversion efficiency. Traditional cooling PV method is using water flowing below the modules to cool down PV temperature. In this paper, the idea is proposed to reduce the temperature of the module and improve the energy conversion efficiency of the module through the modulation of the solar spectrum. A spectrally selective nanofilm reflector located directly on the surface of PV is designed, which can reflect sunlight wavelength with low photon energy, and even enhance absorption of sunlight wavelength with high photon energy. The results indicate that nanofilm reflector can reduce spectral reflectivity integral from 9.0% to 6.93% in 400~1100 nm wavelength range, and improve spectral reflectivity integral from 23.1% to 78.34% in long wavelength range. The nanofilm reflector can reduce temperature of PV by 4.51℃ and relatively improved energy conversion efficiency of PV by 1.25% when solar irradiance is 1000 W/m². Furthermore, the nanofilm reflector is insensitive in sunlight's angle and polarization state, and be suitable for high irradiance environment.

• Journal of Korean society of Dental Hygiene
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• v.23 no.6
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• pp.459-466
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• 2023

Objectives: The purpose of this study was to evaluate the physical properties and antibacterial activity of denture base resin with added silver sulfadiazine. Methods: Specimens were made from self-curing denture base resin and silver sulfadiazine as an inorganic antibacterial agent. For physical evaluation of the specimens, surface roughness, surface hardness, and contact angle were measured. Bacterial growth was assessed by optical densityat 600 nm (OD600) and colony forming units (CFU) measurements to confirm antibacterial activity. Results: There was no significant difference in surface roughness, surface hardness, and contact angle in the experimental group containing silver sulfadiazine compared to the control group. In contrast, the experimental group showed a significant decrease in antibacterial activity compared to the control group in terms of OD value. Analysis of CFU confirmed a significant decrease in colonies in the experimental group compared to the control group. Conclusions: Denture base resin containing silver sulfadiazine, an inorganic antibacterial agent, exhibited enhanced antibacterial activity without physical changes. In conclusion, the use of denture base resin containing inorganic antibacterial agents may be expected in the future.