• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.188-190
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• 2006

본 논문에서는 국내최초로 개발에 성공한 단일용량의120kW급 계통연계형 태양광발전용 PCS에 관한 내용을 설명하고 있다. 120kW급 계통연계형 태양광발전시스템은 22.9kV의 특고압 계통전원에 연계되도록 설계되었으며, 삼상 380V를 22.9kV로 승압 연계하는 2단 절연방식을 채택하였다. 120kW급 PCS는 상용주파수 변압기 절연방식으로 3상4선식 380v 60H2 출력을 가지고 있으며, PCS 내부에 120kVA급 변압기와 리액터를 포함하고 있다. 최대출력점추종(MPPT)제어 기법으로 P&O 알고리즘을 적용하였으며, 3상 IGBT 인버터를 DSP로 제어하였다. 본 논문에서는 120kW급 단일용량 PC를 개발함에 있어, 계통연계 시험, 유,무효 전류제어 시험, 단독운전 검출 및 방지시험, 출력전류의 THD 측정 등의 결과를 보이고 있다.

• Journal of Integrative Natural Science
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• v.9 no.1
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• pp.16-22
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• 2016

The optical and physical and characteristics of hydrogel ophthalmic lens polymerized with addition of 2,6-difluoropyridine, SiPc(silicon 2,9,16,23-tetra-tert-butyl-29H31H-phthalocyanine dihydroxide) and nanodiamond in the basic hydrogel material were evaluated. In particular, the utility of 2,6-difluoropyridine, SiPc and nanodiamond as a hydrogel ophthalmic lens material was investigated. 2,6-difluoropyridine, SiPc and nanodiamond were used as additives. And also, 2-hydroxyethyl methacrylate, acrylic acid, methyl methacrylate and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The refractive index of 1.4348~1.4361, water content of 33.30~34.02%, UV-B transmittance of 4.77~67.50%, UV-A transmittance of 1.45~89.19% and visible transmittance of 32.12~92.21% were obtained. The results of hydrogel lens containing 2,6-difluoropyridine (add 5%) showed antibiosis for staphylococcus aureus. The produced copolymer is suitable for hydrogel soft ophthalmic lenses with antibiotic and anti-UV effect.

• Resources Recycling
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• v.27 no.3
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• pp.8-15
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• 2018

Solvent extraction behavior of light rare earth elements (Pr, Nd) and medium rare erath elements (Tb, Dy) in the HCl-PC88A-kerosene extraction system was investigated in order to separate high-purity light rare earths (Pr, Nd) and medium rare earths (Tb, Dy) in the mixed rare earth chloride solution. In the batch test step, it was confirmed that the separation efficiency was good when the extractant concentration (PC88A) was 0.5 M, the equilibrium pH after extraction was 0.8 to 1.0 (initial pH 1.3 of the feed), the concentrations of hydrochloric acid in scrubbing solution was set as 0.1 M, the concentrations of hydrochloric acid in stripping solution was set as 2.0 M or more. Based on the experimental data obtained from the batch test, the mixer-settler was composed as follows; 4 stages of extraction, 8 stages of scrubbing, 4 stages of stripping, and 3 stages of pickling organic solution. The Mixer-settler was operated for 180 hours, and the operating conditions were continuously adjusted to obtain the high-purity light/medium rare earths. Finally, the purity of light (Pr, Nd) and medium rare earth elements (Tb, Dy) was reached as 3 N class.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.169-180
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• 2020

This study examined the effects of a probiotic complex (PC) containing Lactobacillus plantarum, Bacillus subtilis, and Saccharomyces cerevisiae on growth performance, organ weight, immune parameters, fecal microbial count, and noxious odor in broiler chicks. A total of 216 birds (4-day-old) were fed a basal diet (CON) and a diet supplemented with 0.25% (PC1) and 0.5% (PC2) of PC until 35 days of age. No difference in body weight, feed intake, and FCR was observed among the groups. The intestinal mucosal weight of the PC1 group was greater than that of the CON group without affecting weights of the other organs. Intestinal secretory immunoglobulin A (sIgA) levels in the PC2 group increased significantly (P<0.05) compared with that in the CON group. The PC2 group also had a strong tendency for elevated blood sIgA levels. Dietary PC did not affect the level of interleukin-1β in the blood and mucosal tissues or alter maltase, sucrase, and leucine aminopeptidase activities in the intestinal mucosa. The PC2 group had higher colony-forming units (cfu) for L. plantarum and S. cerevisiae, but lower cfu for E. coli than those in the CON group. Compared to the CON diet, the PC2 diet resulted in a decreased H₂S concentration and a tendency toward decreased CH₃SH concentration. In conclusion, a 0.5% PC diet showed increased sIgA and desirable microbial population, and decreased noxious odor in the feces, suggesting that PC could be applied as an environmentally friendly feed additive in broiler chicks.

• Resources Recycling
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• v.29 no.4
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• pp.51-57
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• 2020

Separation of Co and Ni over Mg from the sulfuric acid solutions using Cyanex272, PC88A and Versatic acid 10 as an extractant was carried out. From the comparative studies about the extraction behavior of Co, Ni and Mg, Versatic acid 10 was superior to Cyanex272 and PC88A for the selective extraction of cobalt and nickel from the mixed solutions. About 98% of Ni and Co were extracted at equilibrium pH 7.0 and less than 5% of Mg was co-extracted by Versatic acid 10. McCabe-Thiele diagram indicated two stages requirement for Co and Ni extraction by 10% Versatic acid 10 at pH 7.0 and phase ratio (A/O) of 2.0. The loaded Co and Ni in organic phase was stripped effectively the sulfuric acid concentration above 70 g/L. 99.78% of cobalt and 98.42% of nickel were stripped.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.54.2-54.2
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• 2011

We present a study of HII regions in M51 using HST/ACS images taken as part of the Hubble Heritage Program. We found about 19,600 HII regions in M51 with $H_{\alpha}$ luminosity in the range of $L=10^{35.5}-10^{39.0}\;erg\;s^{-1}$. The $H_{\alpha}$ luminosity function of HII regions (HII LF) in M51 is well represented by a double power law with its index ${\alpha}=-2.25{\pm}0.02$ for the bright part and ${\alpha}=-1.42{\pm}0.01$ for the faint part, separated at a break point $L=10^{37.1}\;erg\;s^{-1}$. Comparison with simulated HII LFs suggests that this break is caused by the transition of HII region ionizing sources, from low-mass clusters (including several OB stars) to more massive clusters (including several tens of OB stars). The HII LFs with L < $10^{37.1}\;erg\;s^{-1}$ are found to have different slopes for different parts in M51: the HII LF for the interarm region is steeper than those for the arm and the nuclear regions. This observed difference in HII LFs can be explained by evolutionary effects: HII regions in the interarm region are relatively older than those in the other parts of M51. The size distribution of the HII regions is fitted by a double power law with a break at D = 30 pc. The power law index for the small HII regions with 15 pc < D < 30 pc is ${\alpha}=-1.78{\pm}0.04$, whereas ${\alpha}=-5.04{\pm}0.08$ for the large HII region with 30 pc < D < 110 pc. The power law indices of the size distribution are related with those of HII LF, and the relation between the luminosities and sizes of HII regions is fitted well by $L{\propto}D^{3.04{\pm}}$.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.8
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• pp.1120-1127
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• 2011

A feeding trial was conducted to investigate the effect of dietary supplementation of Bacillus subtilis LS 1-2 grown on citrus-juice waste and corn-soybean substrate on growth performance, nutrient retention, caecal microbial population and intestinal morphology in broilers. Three hundred twenty d-old Ross chicks were randomly allotted to 4 treatments on the basis of BW in a randomized complete block design. Each treatment had 4 replicates of 20 chicks in each. Experimental diets were fed in 2 phases, starter (d 0 to 21) and finisher (d 21 to 35). Dietary treatments were; negative control (NC: basal diet without any antimicrobial), positive control (PC: basal diet added with 20 mg/kg Avilamycin), basal diet added with 0.30% Bacillus subtilis LS 1-2 grown on corn-soybean substrate (P1), and basal diet added with 0.30% Bacillus subtilis LS 1-2 grown on citrus-juice waste substrate (P2). Overall BW gain, feed intake and FCR were better (p<0.05) in PC, P1 and P2 treatments as compared to NC. Moreover, overall BW gain and FCR in PC and P2 treatments were greater than P1. Retention of CP, GE (d 21, d 35) and DM (d 35) were increased (p<0.05) in treatments PC, P1 and P2 compared with NC. At d 35, caecal Clostridium and Coliform counts were lower (p<0.05) in treatments PC, P1 and P2 than NC. Moreover, Clostridium and Coliform counts in treatment PC was lower (p<0.05) than P1. Villus height and villus height to crypt depth ratio in both duodenum and ileum were increased (p<0.05) in treatments PC, P1, P2 as compared to NC. However, retention of nutrients, caecal microbial population and intestinal morphology remained comparable among treatments P1 and P2. It is concluded that Bacillus subtilis LS 1-2 inclusion at 0.30% level had beneficial effects on broilers' growth performance, nutrient retention, caecal microflora and intestinal morphology. Additionally, citrus-juice waste can be used as substrate for growth of probiotic Bacillus subtilis LS 1-2.

• Journal of Plant Biology
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• v.36 no.4
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• pp.321-326
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• 1993

Sugar uptake is accompanied with H+-substrate-symport generally. Both H+/sugar-and H+/K+ stoichiometries during the sugar-uptake have been reported to be exactly 1 : 1. This paper reports that the stoichiometries were enhanced dramatically by the addition of CaCl2 into the medium and by the high cell density of 200 $\mu$L pc/mL. The concentration of free Ca2+ ions in the cells increased significantly with cell density. It is suggested that the free Ca2+ ions are responsible for the change of stoichiometry of sugar transport system by regulation of H+ ion level of biomembrane.

• Journal of Mushroom
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• v.16 no.3
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• pp.213-217
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• 2018

This study was carried out to identify medicinal mushrooms with protective effects against oxidative stress in PC12 neuronal cell line, followed by evaluation of their antioxidant property. Extracts of medicinal mushrooms, including Ganoderma lucidum extract (GLE), antler-shaped Ganoderma lingzhi extract (AGLE), Hericium erinaceus extract (HEE), and Sanghuangporus baumii extract (SBE), were screened for cytotoxicity using MTT assay. None of the extracts up to $10{\mu}g/ml$ concentration affected cell viability. These extracts were further checked for their protective effect against oxidative stress-induced reactive oxygen species (ROS) production. Exposure to $50{\mu}M$ $H_2O_2$ induced ROS generation in PC12 cells, which was inhibited only by treatment with AGLE. In addition, inhibition of $H_2O_2-induced$ ROS generation by AGLE was found to be in a dose-dependent manner (2.5, 5, and $10{\mu}g/ml$). Microscopic examination of DCF fluorescence for detection of ROS showed a similar pattern. Further, antioxidant activity of AGLE was determined by ABTS radical cation assay, and its $IC_{50}$ was found to be $46.90{\pm}0.31{\mu}g/ml$. Taken together, these results suggest that AGLE may help to alleviate oxidative stress in PC12 neuronal cells.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.211-214
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• 1988

As a muscular contraction is sustained, the power spectrum of the myoelectric signal is compressed into lower frequencies. The median frequency appears to be the prefered parameters to monitor this compression. This paper describes a technique and a device which provide an estimate of the median frequency using a TMS32020 DSP chip and IBM PC for tracking of this parameter. Results obtained from myoelectric signal are presented and discussed.