• Korean Journal of Materials Research
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• v.16 no.5
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• pp.297-301
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• 2006

Si/Mo multilayer anode consisting of active/inactive material was prepared using rf/dc magnetron sputtering. Molybdenum acts as a buffer against the volume change of the Silicon. Multilayer deposited on RT (reversible treatment) copper foil current collector to enhance adhesion between Silicon and copper foil. Deposited Silicon was identified as an amorphous. Amorphous has a relatively open structure than crystal structure, thus prevents the lattice expansion and has many diffusion paths of Li ion. When deposited time of Silicon and Molybdenum is 30 second and 2 second respectably, electrode has more capacity and good cycle stability. A 3000 nm thick multilayer was maintained 99% of the initial capacity (1624 $mAhg^{-1}$) after 100 cycles. As the increase of the multilayer thickness (4500 nm, 6000 nm), Si/Mo mutilayer anodes show aggravation cycle stability.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.301-302
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• 2006

초고주파 전력 증폭기의 바이어스 전압을 조절하여 온도 변화에 따른 드레인(Drain) 전류의 변화를 억제하기 위한 저가의 능동 바이어스 모듈을 개발한다. 능동 바이어스 모듈을 5 W급 초고주파 전력증폭기에 적용하였을 경우, $0{\sim}60^{\circ}C$까지의 온도변화에 대하여 소모전류 변화량은 0.1 A 이하로 되어야 한다. 본 기술 개발 대상인 능동 바이어스 모듈의 성능 시험을 위한 대상 전력증폭기는 $2.11{\sim}2.17GHz$ 주파수 대역에서 32 dB 이상의 이득과 ${\pm}0.1\;dB$ 이하의 이득 평탄도, -15 dB 이하의 입.출력 반사손실을 가진다.

• Journal of Advanced Navigation Technology
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• v.2 no.1
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• pp.11-21
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• 1998

There have been active research efforts in the development of a dual-use millimeter-wave radiometer as an aircraft landing aid in low visibility conditions. In this paper, we constructed a radiometer operating at the Ka-band where it is relatively easy to build RF components. The radiometer is used to collect radiometric signatures of some vehicles and land surfaces. Measured signatures suggest that vehicles with metallic surfaces yield signatures markedly different from nearby land surfaces so that they can easily be detected by a simple radiometer.

• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.195-199
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• 1997

For the purpose of isolation and screening of tyrosinase inhibitory activity from edible mushrooms, Pleurotus ostreatus, Auricularia auricula-Judae, Umbilicaria esculenta, Agaricus bisporus, Flammuline velutipes, Lentinus edodes, Ganoderma lucidum, and Coriouls versicolor were examined by tracing inhibitory activities against tyrosinase, utilizing L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate. Among the eight edible mushrooms tested, Umbilicaria esculenta showed potent enzyme inhibitory activities above 7804% against tyrosinase in ethylacetate (EtOAc) extracts. Ganoderma lucidum and Agaricus bisporus showed inhibitory activities of 67.3% and 51.5% in water extracts. EtOAc extracts of Umbilicaria esculenta was fractionated from silicagel column chromatography and one fraction showed the most inhibitory activity of 60.9%. The three bands (Rf=0.38, 0.27, 0.19) were isolated from preparative TLC of the fraction for purification and identified as mixtures of orsellinate, methyl orsellinate, methyl lecanorate, and methyl gyrophorate by high pressure liquid chromatography (HPLC), ultravisible spectrophotometer (UV), mass spectrophotometer (Mass), nuclear magnetic resonance spectrometer (NMR).

• Korean Journal of Pharmacognosy
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• v.25 no.1
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• pp.59-69
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• 1994

Polygonum aviculare L. was extracted by methanol and then fractionated systematically with solvents and column chromatographic method in order to isolate ingredients with anti-lipid peroxidation and liver protectective effects. Among these fractions, ethylacetate soluble part(MWE) showed the strongest in the anti-lipid peroxidation. Furthermore, the crude subtraction(MWE 4) with Rf value near 0.42, which is separated from MWE by column chromatography using a solvent system, inhibited the lipid peroxidation of rat liver in vitro. Moreover, MWE 4 decreased GOT, GPT and TBA value compared with control and suggested high protective effects against hepatotoxicity induced by carbon tetrachloride in mice. The active compounds in MWE 4 were assumed to be flavonoid glucosides.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.318-318
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• 2011

Electrosurgery has been widely used in surgical procedures for many years. The surgical procedure using radiofrequency power generated occasionally sparks causing electrical stimulations. According to a paper of commercialized APC (Argon Plasma Coagulation) in the gastrointestinal endoscopy, Patients treated by APC had experienced pain and neuromuscular stimulation. This study aimed to investigate the electrosurgery sparks. In this experiment, current threshold of electrosurgery using rf was investigated. Sparks analogous to surgical situation was generated and measured the I-V figure. Asymmetric current, observed by other researchers, was also measured. This could be explained by difference between positive phase and negative phase. Furthermore, a method was developed to remove asymmetric current and to make safer device for surgical field.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.22-28
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• 1998

A new type of FET source mixer with a single bias voltage has been presented. It is designed to operate at Vds=0 [V] with only one positive supply voltage, which makes mixer circuits simple. The proposed mixer has shown improved stability and less sensitivity to both bias and LO power compared with conventional active mixers. It also shows lower conversion loss than that of diode mixers. The minimum conversion loss measured at RF frequency of 5.6㎓ is 0.6㏈ for a LO frequency of 5.8㎓.

• Journal of electromagnetic engineering and science
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• v.13 no.4
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• pp.208-213
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• 2013

This paper proposes a tag antenna for radio frequency identification (RFID) food system. The RFID tag antenna is designed and fabricated based on the rectangular loop concept used in the UHF band (Korean and Japanese standards, 916.7-923.5MHz). The proposed tag antenna is composed of a radiation patch, sensor tag chip, temperature sensor, oscillator, and battery. We conjugated matching between the tag antenna and the sensor tag using a U-shaped stub. Details of the proposed tag antenna design and the simulated and measured results are presented and discussed.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.117-120
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• 2003

PON (Passive Optical Network) is an emerging local subscriber access architecture that provides more bandwidth and services to subscriber than DSL (Digital Subscriber Line and HFC (Hybrid-Fiber Coaxial) network. A PON is a point-to-multipoint optical network with no active elements in the signals' path from source to destination. Advantages of using PON for a subscriber access network include large coverage area, reduced fiber deployment, multicast and broadcast capabilities, reduced cost of maintenance (due to devices being passive), and ease of upgrades to higher bit rate or additional wavelengths. PON uses WDM (Wavelength Division Multiplexing) technique that transmits the downstream and upstream data at each different wavelength. For transmitting the CATV (Community Antenna television) service through PON network, we give out additional wavelength. This study shows the available TPS (Triple play service) architecture using CATV overlay EPON (Ethernet PON) architecture and analyzes the effects of EPON-based CATV transmission by measuring the power loss fur each wavelength and the power range of the available analog wavelength and RF.

• Journal of Ginseng Research
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• v.20 no.2
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• pp.173-178
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• 1996

Aerobic cells are normally protected from the damage of free radicals by antioxidative on , zymes such as superoxide dismutase (SOD), catalase, glutathione (GSH) peroxidase, GSH S- transferase and GSH reductase which scavenge free radicals as well as nonenzymatic antioxidants such as ceruloplasmin, albumin and nonprotein-SH including GSH. The effects of each component (ginsenoside $Rb_1$, $Rb_2$, Rc, Rd, Re, $Rb_1$, Rf, $Rh_1$ and $Rh_2$) of red ginseng on the antioxidative enzyme activities were investigated in the liver in order to screen antioxidative components of red ginseng. Ginsenoside $Rb_1$ and Rc showed a tendency to increase GSH peroxidase activity, while ginsenoside Rc significantly decreased Cu,Zn-SOD activity. Especially, ginsenoside $Rh_2$ significantly increased catalase activity. These results suggest that ginsenoside $Rh_2$ is an important active component among total saponins of red ginseng.