• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.897-903
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• 2011

This paper presents a highly linear power amplifier MMIC, having an output power level of about 1 watt, based on InGaP/GaAs hetero-junction bipolar transistor(HBT) technology for the 900 MHz band. The active bias circuit is applied to minimize the effect of temperature variation. Ballast resistors are optimized to prevent a current collapse and a thermal runaway. The fabricated power amplifier exhibited a gain of 17.6 dB, an output P1dB of 30 dBm, and a PAE of 44.9 % at an output P1dB from the one-tone excitation. It also showed a very high OIP3 of 47.3 dBm at an average output power of 20 dBm from the two-tone excitation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.873-879
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• 2007

We have implemented a highly efficient 2.14-GHz class-F amplifier using Freescale 4-W peak envelope power(PEP) RF Si lateral diffusion metal-oxide-semiconductor field effect transistor(LDMOSFET). Because the control of the all harmonic contents is very difficult, we have managed only the $2^{nd}\;and\;3^{rd}$ harmonics to obtain the high efficiency with simple harmonic control circuit. In order to design the harmonic control circuit accurately, we extracted the bonding wire inductance and drain-source capacitance which are dominant parasitic and package effect components of the device. And then, we have fabricated the class-F amplifier. The measured drain and power-added efficiency are 65.1 % and 60,3 %, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2697-2702
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• 2014

In this paper, we demonstrated a Ku-band 2W MMIC power amplifier for satellite communication applications. The device technology used relies on $0.25{\mu}m$ GaAs pseudomorphic high electron mobility transistor (PHEMT) of Wireless Information Networking (WIN) Semiconductor foundry. The 2W MMIC power amplifier has gain of over 29 dB and saturation output power of over 33.4 dBm in the frequency range of 13.75 ~ 14.5 GHz. Power added efficiency (PAE) is a 29 %. To our knowledge, this is the highest power added efficiency reported for any commercial GaAs-based 2W MMIC power amplifier in the Ku-band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.805-808
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• 2011

This paper presents a design of high-efficiency and high-power class E power transmitter. The transmitter is composed of 300 Watt class E power amplifier and AC-DC converter. The AC-DC converter converts 220 V and 60 Hz AC to a 290 V DC. The generated DC voltage is directly applied to a bias of the class E power amplifier. Because the converter does not have DC-DC converter unit, it has very high conversion efficiency of about 98.03 %. To minimize the loss at the output of the power amplifier, high-Q inductor was implemented and deployed to the output resonant circuit. As a result, the 13.56 MHz class E power amplifier has a high power-added efficiency of 84.2 % at the peak output power of 323.6 W. The overall efficiency of class E power transmitter, including the AC-DC converter, is as high as 82.87 %.

• 한국해양학회지
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• v.26 no.1
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• pp.67-76
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• 1991

Masan Bay is infamous for its severe eutrophication, exemplified by frequent red tide incidences and anoxic conditions. We carried out daily observations for 16 days at one site immediately after the summer rainy season in 1988 on the basis that shorter observation intervals be necessary to observe a process with high turnover rate. in spite of the relatively short survey period, we could observe dramatic changes in abundance and composition of the phytoplankton populations. Cell densities and chlorophyll concentrations changed in the magnitude of 70 and 10 times, respectively, Skeletonema costatum, a diatom species, dominated the first peak of phytoplankton biomass and was followed by Prorocentrum minimum, a dinoflagellate species, which occurred dominantly in the second peak after about a week, form the viewpoint of time scale, we suggest that at least a weekly sampling might be appropriate in complex coastal environments as Masan Bay. While stratification enabled high production in the surface layer, it hindered the transport of silicate from bottom to the surface, which in turn limited the prolonged growth of diatoms. Ensued second peaks of silicate and diatom abundance in the surface layer suggest periodic flux of silicate from bottom across the discontinuity driven by tidal currents.

• Journal of Advanced Navigation Technology
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• v.12 no.3
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• pp.220-226
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• 2008

This paper proposes the Reconfigurable Doherty Amplifier(RDA) with asymmetric structure which has ${\lambda}/4$ impedance transformer for modulating the load impedance in peaking amplifier path. This structure is possible to implement a compact size for N-stage multi Doherty amplifier and to get almost same characteristics that is compared to conventional Doherty amplifier. To realize the high efficiency amplifier, we were implemented 45 Watts power amplifier at transmitter band of Wideband Code Division Multiple Access(WCDMA) base-station. As a result, in case of WCDMA 1 Frequency Allocation(FA) input signals, this amplifier has obtained a 26.3% Power Added Efficiency(PAE) at 8 dB back-off point from P1dB and an Adjacent Channel Leakage Power(ACLR) is -40.4 dBc at center frequency ${\pm}5MHz$ deviation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.422-427
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• 2005

In this paper, Doherty amplifier is designed by the need of improving the linearity and efficiency of wireless network and repeater for WCDMA. It is designed to maintain the high linearity and efficiency at the low efficiency period of the power amplifier after analyzing Doherty technique using the active load-pull in condition of the high efficiency power amplifier implementation according to the variation of input power. CW 1-tone experimental results at the WCDMA frequency 2.11$\~$2.17 CHz shows that Doherty amplifier, which achieves pore. add efficiency(PAE) 50$\%$ at 6dB back off the point from maximum output power 52.3dBm, obtains higher efficiency of 13.3$\%$ than class AB. finding optimum bias point after adjusted gate voltage, Doherty amplifier shows that IMD3 improves 4dB.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.64-69
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• 2016

This study was conducted to develop a fast and efficient screening method to determine the quantity of fatty acid in peanut oil for high oleate breeding program. A total of 329 peanut samples were used in this study, 227 of which were considered in the calibration equation development and 102 were utilized for validation, using near infrared reflectance spectroscopy (NIRS). The NIRS equations for all the seven fatty acids had low standard error of calibration (SEC) values, while high R2 values of 0.983 and 0.991 were obtained for oleic and linoleic acids, respectively in the calibration equation. Furthermore, the predicted means of the two main fatty acids in the calibration equation were very similar to the means based on gas chromatography (GC) analysis, ranging from 36.7 to 77.1% for oleic acid and 7.1 to 42.7% for linoleic acid. Based on the standard error of prediction (SEP), bias values, and $R^2$ statistics, the NIRS fatty acid equations were accurately predicted the concentrations of oleic and linoleic acids of the validation sample set. These results suggest that NIRS equations of oleic and linoleic acid can be used as a rapid mass screening method for fatty acid content analysis in peanut breeding program.

• Journal of architectural history
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• v.27 no.2
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• pp.51-62
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• 2018

This study examines the site and erection of the Government Complex Seoul which was a project attempted to assemble dispersed government buildings in a certain place. The study focuses on the fact that the project is situated between the 1960s' making of capital Seoul and Seoul urban planning, and the way how the project achieved symbolism in capital Seoul. The project, one of the 1960s' Major Government Buildings, led both plan of capital Seoul and transforming city Seoul. The 1960s' Major Government Building Plan had identical drive with the 1950's Major Government Building Plan, however the 1960s' had additional layer: Seoul urban planning. After restoration of the Capital building, Sejongro the capital street was planned to the site arranging government offices. The Government Complex Seoul was set to be a modern building on a site with historical context according to the plan. Because of the site, the Government Complex Seoul was constructed in aware of other buildings that represented a competitive high-rise atmosphere in the late 1960s, including the Capital building nearby. PAE International's plan was completed through a series of design modification, and it boasted a vertical aspect, unlike the horizontal-looking plan that was already won after the design competition. The Government Complex Seoul tried to acquire the symbolism in the central space of the capital Seoul and high-rised city Seoul. "The new construction method" was a requirement to achieve the height.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.244-251
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• 2002

Introduction: SLE is autoimmune disease to appear systemic pathology in the connective tissue. Perniotic LE is sub-type of chronic dermal LE which causes purple macules on the terminal part of body-nose, ends of fingers, heals, calfs of the legs, elbows and knees. Objective: The purpose of this study was to estimate the efficiency of oriental medical treatment and management on the SLE and perniotic LE. Subject: We studied 2 patients who visited and hospitalized in Daejon University Oriental Hospital Dept. of Dermatology, with SLE and pemiotic LE from April 2002 till May 2002 Method: We treated them with herb medication, acupuncture and in addition to we consulted western medication if they were needed Results: In case of SLE patient, we considered it to be Yeol-Dok-Chi-Seong, so we priscriped Ga-Mi-So-Dok-Eum1, 2 , Yang-Dok-Baek-ho-Tang first. and till 22 days of hospitalization, we considered to be Gi-Eum-Yang-Heo and priscriped Ji-Hwang-Tang-Hab-Cheong-Sim-Yeon- Ja -Eum-Ga-Mi. but it wasn't adjust and high fever was reaccurred. And till 24 days of hospitalization we priscriped Gal-Geon-Hae-Gi-Tang, and becomed to 25 days, high fever was disappeared and the patient discharged and she has remained generally good condition. In case of Perniotic LE, at first we misdiagnosed her disease as a acral lentiginous melanoma, and we considered it to be Gan-Soo-Yeol-Li-Yeol- Jeung and priscriped Cheong-Pae-Sa-Gan-Tang and transferred her to another hospital, but she was diagnosed Perniotic LE Conclusion: Considering the above results, in case of SLE, in acute phase, we could treat her with oriental-western treatment, and in relief phase, we could treat her with only oriental treatment very efficiently. but in case of perniotic LE, we misdiagnosed it as a acral lentiginous melanoma, but we could experienced very rare perniotic LE case. And also further study is needed on the SLE, and perniotic LE, and we have to systematize of dyagnosis and treatment system.