• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3C
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• pp.302-313
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• 2010

In this paper, we propose an enhanced AGC (Automatic Gain Control) structure and P-SCH detection method for initial cell search in 3GPP (3rdGenerationPartnershipProject) LTE (Long Term Evolution) FDD(Frequency Division Duplex) / TDD (Time Division Duplex) dual mode system. Since TDD frame structure consists of uplink subframe and downlink subframe, conventional AGC structure causes P-SCH detection performance degradation by increase of AGC variation due to signal power difference between uplink and downlink subframe. Also, P-SCH detection performance is degraded by distortion of P-SCH correlation characteristic in frequency offset and multipath fading channel environments. Therefore, we propose an AGC structure which can minimize P-SCH detection performance degradation with stable operation in 3GPP LTE TDD mode as well as FDD mode. Also we propose a P-SCH detection method which can reduce distortion of correlation chareteristics in frequency offset and multipath fading environments and obtain good P-SCH detection performance. Simulation results show that the proposed AGC structure and P-SCH detection method have stable AGC operation and excellent P-SCH detection performance for 3GPP LTE TDD / FDD dual mode downlink receiver in various channel environments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1327-1336
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• 2012

In this paper, the dual-faced monopole antenna, which is arranged by numerous rectangular ring patches in sequence for the multi-bands is proposed. The ring type structure of the patch can be increased the bandwidth. Therefore the bandwidth and beam width are improved by using multiple arrayed patches. When the ring type patches are inserted serially, the resonance frequencies are occurred by the current flow from the first ring patch. It is possible because the gap between the patches is very narrow. In addition, if the patches are composed on the same plane as the feed-line, fabrication could be very difficult because the gap between the patches is extremely narrow. The thickness and permittivity of the antenna, moreover, are very important parameters because both sides of the substrate are used. We finally found the optimal thickness and permittivity to generate the coupling effect by simulation. All patches are consisted of 4-steps which the patch size was decreased 85 % by each step. In conclusion, the resonant frequency bands are 1.75~2.6 GHz(850 MHz), 3.24~3.46 GHz(220 MHz), 3.8~4.0 GHz(200 MHz), and 4.4~4.9 GHz(500 MHz).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.892-899
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• 2016

In this paper, an X-band 50 W internally matched power amplifier is designed and fabricated using an $80{\times}150{\mu}m$ GaN HEMT that is developed by the $0.25{\mu}m$ GaN HEMT process of ETRI. The optimum source and load impedances are experimentally extracted from the loadpull measurement using impedance-transform-prematching circuits, and the transistor performance is predicted. The power performance of the internally matched power amplifier, whose matching circuits are fabricated on a substrate with ${\varepsilon}_r$ of 10.2, is measured under the pulsed mode of $100{\mu}s$ pulse period and 10 % duty cycle, and the best output power of 47.46 dBm(55.5 W) and the power-added efficiency of 46.6 % are obtained at 9.2 GHz. The output power of 47~47.46 dBm(50~55.7 W) is measured in 9.0~9.5 GHz, and the power-added efficiency is measured to be greater than 43 % in 9.0~9.3 GHz and above 36 % in 9.4~9.5 GHz.

• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.528-533
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• 2010

Cage plots were established in 2008 to find the relationship between combination of tended Japanese red pine sapling and the habitation of Monochamus alternatus, a vector for pine wood nematode. Japanese red pine sapling tended at different times were successively put into the cage, and then the adult of Monochamus alternatus was put in June. Presence or absence of the larva was determined November. Sapling tendings were done at seven successive times in 2009, mid- and late February and March, mid-April, May and June. Some saplings were also tended in mid-October of 2008, the previous year of this experiment. The larva was found in all the saplings tended later than mid-March in 2009. No larva was found in the saplings tended in mid-October of 2008 and those in February of 2009. In case of the combination the by-products of mid-February and late March of 2009 and mid-October of 2008, the larva was found in the by-product of mid-February and late March of 2009, but those in mid-October of 2008 was not. When the saplings tended in mid-October of 2008 and mid- and late February of 2009 were put into the cage singly, the larva was found in all the saplings. Results indicated the mixture of the saplings tended at different times affected the habitation of Monochamus alternatus differently.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.5
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• pp.574-579
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• 2009

Physicochemical properties of flowering cherry (Prunus yedoensis, Prunus sargentii, Prunus lannesiana, Prunus cerasus) fruits were evaluated. The moisture contents were the highest in fruits of Prunus cerasus; crude protein ranged from $0.19{\sim}1.49%$ and crude fat ranged from $1.00{\sim}2.66%$. The fruits of Prunus lannesiana included higher contents of crude ash compared with those of other cultivars. The mineral contents of Prunus lannesiana fruits were the highest in Ca, K, Mg, Fe, and Mn. The amino acid contents of only methionine was the highest in fruits of Prunus sargentii (1.64 mg/L). Other amino acids were the highest in fruits of Prunus cerasus. The Brix value was the highest in fruits of Prunus yedoensis, followed by fruits of Prunus sargentii, Prunus lannesiana, and Prunus cerasus. Organic acid contents ranged from $3.42{\sim}4.18%$. Anthocyanin contents were the highest in fruits of Prunus sargentii in methanol extract. Therefore oriental cherry commensurates with development of nature pigment and functional foods. Especially, Prunus cerasus was greater than other cultivars.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1425-1432
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• 2010

This study was designed to investigate the effects of antioxidant and antibacterial activities of water, ethanol and methanol extracts from root, stem and flower stalk of Hagocho (Prunella vulgaris). The solvent extract yields from root were higher than those from stem and flower stalk, and water extract showed the highest extraction yield against ethanol and methanol extracts. The contents of total phenolic and flavonoid in ethanol extract were significantly higher in stem extract compared with those of root and flower stalk. In the case of water and methanol extracts, however, the contents were the highest in flower stalk. The electron donating ability and reducing power in all test groups were significantly increased in a dose-dependent manner, and antioxidant activities were the highest in methanol extract. In extracts from different parts of Hagocho, the antioxidant activity was the highest in flower stalk followed by stem and root. ABTS radical scavenging ability of water and methanol extracts was above 50% at $100\;{\mu}g/mL$ concentration. Antibacterial activities did not show significant differences depending on parts of Hagocho. However, antibacterial activity of ethanol extract was higher than those of other extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1487-1494
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• 2010

Structured lipid (SL) for cocoa butter alternative was synthesized by interesterification of coconut oil fraction and palm stearin (6:4 and 8:2, by weight) in a shaking water bath at $60^{\circ}C$ and 180 rpm. It was performed for various reaction times (1, 2, 3, and 6 hr). The reaction was catalyzed by sn-1,3 specific Lipozyme TLIM (immobilized lipase from Thermomyces lanuginosus). SL-solid part was obtained from acetone fractionation at $0^{\circ}C$. SL-solid part was blended with other palm oils and fractions for desirable property of cocoa butter alternative (SL-solid part : palm middle fraction : palm stearin solid : palm oil, 70.4:18.4:2.9:8.3, by weight). In reversed-phase HPLC analysis, triacylglycerol species of cocoa butter alternative had partition number of 40 (10.77%), 42 (13.06%), 44~46 (17.38%) and 48 (51.88%). Major fatty acids of cocoa butter alternative were lauric acid (16.5%), myristic acid (12.28%), palmitic acid (46.03%), and linoleic acid (14.75%). Solid fat content (SFC) and polymorphic form (${\beta}'$ form) of cocoa butter alternative prepared were similar to those of commercial cocoa butter replacer (CBR).

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.792-799
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• 2013

This study was designed to develop natural browning inhibitors. The anti-browning effects of distilled water (SBD) and 80% ethanol extracts (SBE) of Scutellaria baicalensis Georgi in apple slices were investigated by L and ${\Delta}E$ values. Both SBD and SBE were effective in reducing the browning of apple slices and were successively fractionated into chloroform ($CHCl_3$), ethyl acetate (EtOAc), and water ($H_2O$) fractions. These extracts were measured for total phenolic content, flavonoid content, anti-oxidative activity (through free radical scavenging activity and the FRAP assay), ferrous ion chelation, and the inhibition of PPO (polyphenol oxidase) activity. Overall, fractions of SBE were better than fractions of SBD in all measurements. The highest total phenolic and flavonoid content were measured in the EtOAc and $CHCl_3$ fractions of SBE. EtOAc and $CHCl_3$ fractions also exhibited the highest anti-oxidative activities (in DPPH and ABTS free radical scavenging and the FRAP assay). Unusually, the highest ferrous ion chelating capacity was found in the $H_2O$ fraction of SBD, but the other fractions showed more than triple the ascorbic acid already in use. Also, $CHCl_3$ fractions showed a stronger inhibition of PPO activity than ascorbic acid. All of these results suggest that EtOAc and $CHCl_3$ fractions from Scutellaria baicalensis can be used as natural anti-browning agents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1414-1418
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• 2017

Inhibition of advanced glycation end product (AGE) formation is a valuable therapeutic strategy for the regulation of diabetic complications. This study was conducted to identify potential therapeutic targets of anti-diabetic complications from irradiated mangiferin using AGE formation assay. Radiolytic degradation of the xanthone glucoside mangiferin by gamma-irradiation resulted in three degraded mangiferin analogues: mangiferdiol (1), mangiferinol (2), and isomangiferinol (3). Structures of the three newly generated compounds were characterized by interpretation of nuclear magnetic resonance ($^1H$, $^{13}C$ NMR, $^1H-^1H$ COSY, HSQC, HMBC, and NOESY) and mass spectroscopic data. The anti-diabetic complication of the generated mangiferin derivatives were tested using in vitro AGE formation method. Among the tested degraded products, mangiferinol (2) and isomangiferinol (3) exhibited significantly improved potency against AGE formation inhibitory activities with $IC_{50}$ values of $5.6{\pm}0.8$ and $7.6{\pm}0.9{\mu}M$, respectively. This result implies that xanthone derivatives generated from gamma-irradiated mangiferin might be beneficial for prevention of diabetic complication and related diseases.

• Journal of Gastric Cancer
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• v.6 no.4
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• pp.221-226
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• 2006

Purpose: Controversy still exists over in the prognostic significance of microscopic tumor cell dissemination in patients with cancer. This study evaluated the prognostic implication of isolated tumor cells in the bone marrow of patients with gastric cancer. Materials and Methods: Four hundred nineteen (419) patients who underwent surgery for gastric cancer between June 1998 and July 2000 were enrolled in the study. Bone marrow aspirate was obtained from the iliac crest before removal of the primary tumor. Mononuclear cells were isolated and stained with AE-1/AE-3 PAN-CYTOKERATIN. Results: Cytokeratin-positive cells were found in the bone marrow of 219 patients (52.3%). The incidence varied significantly with the depth of invasion (P=0.021) and the stage (P=0.026). The five-year survival rate of patients with cytokeratin-positive cells was 74.1% and that of patients without cytokeratin-positive cells was 81.1%(P=0.2481). There were no significant differences in the recurrence rate and the site of recurrence according to whether or not cytokeratin-positive cells were present in the bone marrow. Conclusion: The presence of cytokeratin-positive cells in the bone marrow of patients with gastric cancer did not predict outcome and recurrence. Therefore, it cannot be used as a prognostic factor.