• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.460-467
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• 2022

The purpose of this study is to enhance utilization of the waste nutrient solution (WNS) disposed at the hydroponic greenhouse. Several sets of testing were conducted to examine the effects of WNS: (a) a fertilizer effect, (b) soil column leaching, and (c) crop cultivation. The fertilizer effect test was applied in young radish cultivation by examining the growth characteristics of young radish and soil based on inorganic nitrogen according to the soil treatment of the nitrogen fertilizer (NF) and the WNS. The fertilizer effects and crop cultivation test were conducted with five treatments (A-E): A, non-treatment (water); B, 100% of NF; C, 70% of NF + 30% of WNS; D, 50% of NF + 50% of WNS; and E, 30% of NF + 70% of WNS. The soil column leaching test was conducted with three treatments: non-treatment (water), 100% of NF, 50% of WNS + 50% of NF. As a result, the chemical properties of the WNS were pH 6.0, EC 2.4dS·m^-1, total phosphorus (T-P) 28mg·L^-1, ammonium nitrogen (NH₄-N) 5.0mg·L^-1, and nitrate nitrogen (NO₃-N) 301mg·L^-1. The chemical properties of the soil were pH 5.51, EC 0.31dS/m, organic matter 2.08g·kg^-1, NO₃-N 9.64mg·kg^-1, and NH₄-N 3.20mg·kg^-1. The results of fertilizer effects showed that the ratio of 50% or less of NF and 50% or more of WNS was high in young radish growth. There was no statistically significant difference between the soil chemistry in the C-E treatments where WNS was mixed with NF and the B treatment where only NF was applied. As a result of the soil column leaching test, there was no significant difference in the concentrations of NO₃ and NH₄ in the treatment of 100% of NF and 50% of NF + 50% of WNS. The study indicates, if the mixed fertilizer of WNS and NF is applied in the soil cultivation of young radish, it will reduce the use of NF and environmental pollution. This also helps reduce production costs on farmers and increase the yield of young radish.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3880-3884
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• 2010

In this paper, circularly polarized micro-strip GPS antenna has been designed and fabricated. In order to improve of frequency properties, patch size, corner truncated size and feed positions were simulated using HFSS simulation program. Micro-strip GPS antenna was fabricated on the FR4 substrate of dielectric constant 4.4. The fabricated GPS antenna has that center frequency is 1.575GHz and insertion loss is -34.50dB.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.257-261
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• 2001

This paper presents the implementation of wide-band RFIC amplifier operating from near 50MHz to 3GHz using Tachyonics SiGe HBT foundry. Voltage shunt feedback is used for the flat gain and the broad band impedance matching. Initial design parameters are calculated using the low frequency small signal analysis. Since the HBT model was not available at the design time, discrete tuning board was made for fine tuning in the low frequency range. Fabricated amplifier shows 12dB gain with 1dB fluctuation and PldB reaches 15dBm at 850MHz.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.733-734
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• 2006

Granulated powders, prepared from PF-5F($D_{50}=4(\mu}m$), PF-10F($D_{50}=6{\mu}m$) and PF-20F($D_{50}=10{\mu}m$) water atomized powder, were compacted, debound and sintered to evaluate the properties of sintered parts. As a result, the relative sintered density of about 97% at sintering temperature of 1423K was obtained. It can be considered that by using granulated finer particle size powder, mechanical properties of sintered parts were also improved.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.28-31
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• 2008

22.9kV 50MVA HTS power cable has been developed and tested by Korea Electrotechnology Research Institute and LS Cable Company and it was supported by a grant from Center for Applied Superconductivity Technology of the 21st Century Frontier R&D Program. In this paper, DC Ic of 100m HTS cable which is installed at Kochang testing station was measured and analyzed. A measurement technique of DC Ic used by resistance and inductance removal method is established.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.4
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• pp.724-728
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• 2002

Angiotensin-converting enzyme (ACE) gene polymorphism, which consists of presence (insertion, I) or absence (deletion, D) of a 250-bp fragment, is associated with ischemic heart disease, renovascular disease, systemic lupus erythematosus. Subjects with the DD genotype have higher levels of circulating ACE than subjects with the II genotype and show an increased tendency towards vascular wall thickness and contribute to the development of vascular disease. But the association between I/D polymorphism of the ACE gene and cerebrovascular disease is still controversial. The aim of this study was to determine whether the DNA polymorphism of the ACE are associated with cerebrovascular disease in Korean population. The study group comprised 377 Korean patients admitted to Kyunghee Oriental Medical Center in the year of 2000 for the treatment of brain infarction or brain hemorrhage. Magnetic resonance imaging(MRI) was performed for each patient to determine the stroke phenotype, infarction or hemorrhage. The 183 subjects without evidence of brain infarction or brain hemorrhage were selected from the some ethnical population(control group). Venous blood samples were drawn from each subject for the extraction of DNA. Genotypes of ACE were determined by polymerase chain reaction amplification of the genomic DNA. Case and control genotype frequencies were compared by chi-square testing. Both the patients and the controls were classified respectively into 4 groups: age less than forty years, age forty one to fifty, age fifty one to sixty, age greater than sixty years. There were no significant differences in the distributions of ACE genotypes among the patients with infarction, with hemorrhage and controls (Infarction: D/D 15.8%, I/D 46.7%, I/I 37.5%, Hemorrhage: D/D 15.1%, I/D 46.5%, I/I 38.4%, Control: D/D 18.6%, I/D 50.3%, I/I 31.2%). There was a significant difference in the distribution of ACE genotypes between the age greater than sixty year subgroup of patient with brain hemorrhage and the control (Hemorrhage: D/D 0%, I/D 55.6%, I/I 44.4%, Control: D/D 13.0%, I/D 63.0%, I/I 23.9%; Pearson Chi-Square value 5.956, P<0.05). Furthermore, the frequency of the ACE D/D type declined with increasing age both in the patient and control group (Patient group: age < 50 D/D 21.5%, age > 50 D/D 14.42%; Control group: age < 50 D/D 21.0%, age > 50 D/D 14.2%). In conclusion there is no clear association between ACE polymorphism and cerebrovascular disease in Korean population. Although, there was a tendency for the frequency of the ACE D/D type declined with increasing age in both patients and controls.

• Journal of Korean Clinical Health Science
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• v.1 no.3
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• pp.33-37
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• 2013

Purpose. In this study, we divided elementary school students into two investigated groups. The A group is the lower graders(boys 9, girls 18), and the B group is the higher graders(boys 10, girls 13). The myopia progression has been compared with to each group and it has been investigated for variable terms. Methods. We have analyzed the refraction inspection record of 50 students(boys 19, girls 31) who visited optical shops and more than two times in one year. Results. The subject of study were 50 students(boys 19, girls 31). 1. The distribution of spherical equivalent power with ages : boys A group -2.42D, girls A group -2.53D, boys B group -2.63D, girls B group -2.78D. boys B group -2.63D, girls B group -2.78D. 2. The monthly variation of spherical equivalent power : -0.055D(A), -0.04D(B) in boys, and -0.065D(A), -0.07D(B) in girls. Conclusions. Considering monthly variations and Supposing that the time of changing spectacles degrees were the time of refracting inspection. The result : 3.8 month for A group, 4.5 month for B group in boys, and 3.5 month for A group, 5.2 month for B group in girls.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.79-86
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• 1999

A simulation of 10 Gbps optical fiber transmission system using DCf(dispersion compensating fiber) for the dispersion compensation is performed. In order to analyze the NRZ pulse propagation in nonlinear, dispersive and lossy fiber, the split-step finite element method that is combination of finite element method and finite difference method is used. Also, we obtained the optical eye diagram and BER characteristics at the receiver of the system that is contained the optical amplifier and system noises. As a result of simulation, we obtain that the dispersion penalty is about 0.8dB after 50km transmission and the receiver sensitivities at $10^{-9}$ BER are -27.4dBm with EDFA pre-amplifier of 12dB gain and -15.6dBm without EDFA.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.3
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• pp.203-208
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• 2009

Doenjang (Korean fermented soybean paste) is a unique fermented food in Korea. It has been traditionally manufactured from soybeans, by Jang Yang process. We focused on the newly formed compound in highly aged Doenjang and its biological activity. One new o-dihydroxyisoflavone, 7,3',4'-trihydroxyisoflavone and two known o-dihydroxyisoflavone derivatives were isolated from 5-year-old Doenjang and evaluated as potent antioxidant and whitening effect by comparing with other known isoflavone. 7,8,4'-Trihydroxyisoflavone (compound 1), 7,3',4'-trihydroxyisoflavone (compound 2) and 6,7,4'-trihydroxyisoflavone (compound 3) inhibited DPPH (diphenyl-1-picrylhydrazyl) formation by 50 % at a concentration of $21.5{\pm}0.2$, $28.7{\pm}0.4$ and $32.6{\pm}0.6$ ($IC_{50}$) respectively, whereas daidzein showed weak DPPH radical scavenging activity. In superoxide scavenging effect were measured in one assay. Compound 1 ($IC_{50}=18.10{\pm}0.2{\mu}M$) and 2 ($IC_{50}=10.54{\pm}0.4{\mu}M$) show significant inhibitory activity and greater effect than L-ascorbic acid. But compound 3 and daidzein showed lower inhibition activity. Also, o-dihydroxyisoflavone derivatives evaluated as potent inhibitors on tyrosinase activity and melanin formation in melan-a cells. Compound 1 ($IC_{50}=11.21{\pm}0.2{\mu}M$), compound 2 ($IC_{50}=5.23{\pm}0.6{\mu}M$) exhibited significant inhibitory effect on tyrosinase activity. Furthermore, those compounds are significantly suppressed the cellular melanin formation by 50 % at a concentration of $12.23{\pm}0.7{\mu}M$ (1) and $7.83{\pm}0.7{\mu}M$ (2). This result suggests that 7,3',4'-trihydroxyisoflavone from highly aged Doenjang could be used as an active ingredient for cosmetics.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.403-417
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• 2017

This study was done to elucidate effects on organic and chemical fertilizers for growth characteristics, saponin content and antioxidant activity in Platycodin grandiflorum Ridix root. Chemical and mixed organic fertilizers were treated at levels of 50%, 100% and 200% based on nitrogen 3 kg/10a before transplant of Platycodin grandiflorum Ridix. As a result, when 50% mixed organic and chemical fertilizer plots were treated to P. grandiflorum Ridix root, the root length showed the highest scores of 26.9 and 26.5 cm, respectively. Root width exhibited the highest scores of 25.6 mm and 25.2 mm in 50% mixed organic and chemical fertilizer plots, respectively. The number of fine-roots and fresh weight presented the highest values in 50% mixed organic fertilizer plot as 26.7 and 50.4 g, respectively. The content of platycodin D3 was ranged in 183.4~321.7 mg/100 g, which the highest value was observed in 100% mixed organic fertilizer plot. The content of saponin except for deapioplatycodin D presented higher amount in the mixed organic fertilizer plots. Treatment of 200% chemical fertilizer presented to be withered in transplant cultivation of 3 year-old roots.