• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.102-112
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• 2005

In this work, we developed fully integrated broadband MMIC chip set employing CSP(Chip Size Package) for K/Ka band applications. By utilizing an ACF for the RF-CSP, the fabrication process for the packaged amplifier MMIC could be simplified and made cost effective. $STO(SrTi_{3})$ capacitors were employed to integrate the DC biasing components on the MMIC, and LC parallel circuits were employed for DC feed and ESD protection. A pre-matching technique and RC parallel circuit were used to achieve a broadband matching and good stability fer the amplifier MMIC in K/Ka band. The amplifier CSP MMIC exhibited good RF performance over a wide frequency range in K/Ka band. This work is the first report of a fully integrated CSP amplifier MMIC successfully operating in the K/Ka band.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.95-95
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• 1995

뇌신경 변성 / 퇴행과 관련된 중요한 병인론 중의 하나는 변성 과정에서 형성된 유리기(free radical)로 인한 항산화계의 평형 소실로 알려져 있다. Aspalatone (APT)의 예상되는 항산화 효능을 검정하기 위하여 본 실험에서는 Kainic acid (KA) 유발 뇌변성 모델을 적용하였다. KA 모델은 변연계의 간질성 경련과 신경세포 변성에 대하여 재현성 있는 병변 모델을 제공해 주며, 이와 같은 신경세포의 병독 기전에 산소 유리기가 관여함이 강력히 시사되고 있기 때문이다. KA 투여로 인하여 지속적이고도 전형적인 간질성 경련이 관찰되고 1일 이내에 높은 치사율을 보였으나 APT으로 인하여 그 간질성 경련 행위와 비율이 억제되고 KA 유발 치사율도 억제되었다. 최종 KA 투여 3일 후에 얻어진 흰쥐 해마 및 대뇌 피질에서 항산화 효소인 Superoxide dismutase (SOD), Catalase (Cat.), Glutathione peroxidase (GSH-PX) 및 과산화지질의 지표인 Malondialdehyde (MDA)를 검정하였다. 대조군에 비하여 KA는 뇌조직의 SOD-1을 유도하였으나, Cat.와 GSH-PX의 활성은 현저히 유도되지 않았고, 반면에 MDA 치는 현저히 증가하였다. 즉, Cat., GSH-PX와 같은 $H_2O$$_2$중화제가 동반 유도하지 않는 SOD의 유도는 세포내 축적되는 $H_2O$$_2$로 인하여 Fenton/Haber-Weiss 반응을 가속화하여 과산화지질화를 촉진함을 시사한다. APT 병용 투여로 SOD는 현저히 유도되지 않았으나 특히 Cat.가 현저히 유도되어지고 MDA는 억제되었다. 이와 같은 생화학적인 결과는 다음의 형태학적인 소견과 일치한다. Fos 관련 항원 (FRA)와 SOD-1을 면역세포화학 (Immunocytochemistry)적 방법으로 이중 표식 (double-labelling) 하였다. FRA는 KA로 인한 신경세포의 자극에 대한 지표로 응용하였고, SOD-1은 퇴행성 뇌질환에서 산화적 손상의 지표로 사용하였다. KA 투여로 해마의 dentate gyrus (DG) 내에 강한 면역환성 (immunoreactivity)이 나타났고 pyramidal cell layer (PCL)와 glia에 SOD-1이 강하게 염색되었다. APT 병용 투여로 상당수의 경련이 일어나지 않은 흰쥐는 해마의 DG에 FRA가 경미하게 염색되었고, PCL에 SOD-1도 경미하게 나타났으나, 경련이 나타난 쥐에서는 KA만을 투여한 흰쥐와 구별되지 않았다. 이상의 APT의 항산화 효과는 KA로 인한 뇌세포 변성 개선에 중요한 인자로 작용할 것으로 사료되나, 보다 명확한 APT의 기전을 검색하고 직접 임상에 응응하기 위하여는 보다 다양한 실험 조건이 보완되어야 찰 것으로 생각된다.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.115-115
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• 2014

First, We will briefly introduce early science results of AGN observations with KVN and KaVA. KaVA is the combined array of the Korean VLBI network (KVN) and VLBI Exploration of Radio Astronomy (VERA). These include KaVA monitoring of M87, Sgr A* and a few bright blazars and KVN Search for circular polarized Blazars. Furthermore, we will present our future plan of monitoring observation of Sgr A* and M87 with KaVA and Low Radio Power AGN multi frequency polarization survey with KVN. Because of the largeness of their centralsuper-massive black holes, we select them as top-priority sources of our key science program (KSP). The main science goals of the KaVA KSP are (1) mapping the velocity field of the M87 jet and testing magnetically-driven-jet paradigm, and (2) obtaining tightest constraints on physical properties of radio emitting region in Sgr A. High sensitivity achieved through simultaneous multifrequency phase referencing technique of KVN will allow us to explore Low Radio Power AGN cores which build majority of AGNs and therefore are important for undestanding the evolution of AGNs and of their hosts.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.1
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• pp.65-68
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• 2004

The performances of millimeter wave Power amplifier have been improved by using PBG (photonic bandgap structure) in this paper. The PBG structure has been optimized to obtain the lowpass characteristics in Ka band and employed at output port of Ka band power amplifier. The harmonics of the power amplifier have been suppressed by the PBG of output port and the proposed PBG has suppressed the second harmonic to 40dBc around 50 GHz. The improvements of IMD and PAE of the amplifier employing the PBG structure are obtained $15\%$ and $25\%$, compared with those of the conventional Ka band power amplifier, respectively.

• The Journal of the Acoustical Society of Korea
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• v.14 no.6
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• pp.21-26
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• 1995

In this paper integral equations are derived and simulated numerically for the mutual radiation impedance of an acoustic transducer in a Plane array. It is assumed that the pistons are mounted in the rigid infinite baffle. The mutual radiation impedance is separated into resistance and reactance and plotted as a function of ka and kd. Mutual radiation resistance is decreased and perturbed according to increase of ka. Mutual radiation reactance is decreased along to increase of ka. Mutual impedance is decreased when kd is increased. However, when ka is 6, 13, and 19 the interaction effect is decayed. When the relative piston position of the two pistons is 45 degree, the amount of interaction becomes minimized.

• Natural Product Sciences
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• v.16 no.2
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• pp.99-106
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• 2010

This experiment was undertaken to investigate whether methanol extract of fruit peel of Dimocarpus longan Lour. (MEFL) protects against kainic acid (KA)-induced seizure. Oral administration of MEFL (1, 2 and 4 mg/kg) increased KA (50 mg/kg)-induced survival rate and latency of convulsion onset, and deceased seizure scores and weight loss induced by intraperitoneal (i.p) injection of KA in mice. In addition, MEFL protected against cell death in the hippocampus of rat brain after KA-administration as analyzed by using TUNEL assay in rats. MEFL also significantly blocked seizure-form of electroencephalogram (EEG) power spectra induced by KA in rats. MEFL also inhibited elevation of [$Ca^{2+}$]i and increased [$Cl^-$]i induced by KA in cultured neuronal cells. Therefore, it is suggested that MEFL protects against seizure induced by KA, decreasing [$Ca^{2+}$]i.

• Journal of the Korean Society of Clothing and Textiles
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• v.14 no.2
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• pp.85-97
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• 1990

This study investigates, through the Ka-rae-ban-cha-do(가예반차도) in the Ka-rae-do-gam­eui-gue (가예도감의궤), how the system of costume used in ceremony exchanged during the middle, late the Yi dynasty and in the period of introducing Wastern civilization. The procedure of the royal marriage is also studied here. The procedures of Ka-rae were divided into the six traditional etiguettes(륙예) : Nap-che (납채) , Nap-gyng(납징), Go-gi(고기), Chaik-bi(책비), Chin-young(친영), and Dong-roe(동뢰). The change of the general structure and characteristic of the costume used in the ceremony in Ka-rae-ban-cha-do are as follows: The costume in Ka-rae-ban-cha-do can be divided into the Guard costume (호위복식) and the Ceremonial arms costume (의장복식). The most formal attire of the Guard costume, Yangkwan-Chobok (양관-조복) and Samo -Danryeong(사모-단령) with Huygpai(흉배) can be seem only in the Ka-rae of late king's. Of the Ceremonial arms costume, the most outstanding was Hongkun- Hongeui (홍건-홍의), which showed up in almost all Ka-rae-ban-cha-do. Heukkun-Changos$\cdot$Deogrei (흑건-창옷$\cdot$더그레) were worn as well. In the style of costume emphasis convenience and practicality rather than on beauty, because they had to carry the arms used in ceremony with them nevertheless by using primary colors it was very colorful. This costume in Ka-rae-ban-cha-do has little difference, but great changes are shown in Sunjongsunjongbi Ka-rae-ban-cha-do (순종순종비가례반차도). Most costume of the past was replaced with western hat and suit, so the duplicate state of our costume and western costume came into existence during the period of introducing western civilization.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.86-91
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• 2012

This paper described validation results of COMS Ka band antennas beam coverages which were developed by ETRI. After satellite launch, In Orbit Test(IOT) activities are stat to check spacecraft and payloads are still in healthy condition after launch. During IOT phase, ETRI measured radiation patterns of COMS Ka band antennas and compare with ground test(CATR) results. The antenna patterns similarity between IOT results and CATR results show that COMS Ka band antenna withstand launch vibration and in the good healthy condition. After IOT, ETRI performed field test for beam coverage measurements with vehicle to check if Ka band beam coverage are formed well as designed. For the beam coverage measurement, 17 points were selected over the Korean peninsula. The field measurement data were very similar with CATR data and this confirms that beam coverage are formed well over the Korean peninsula as expected.

• The Korean Journal of Quaternary Research
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• v.33 no.1_2
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• pp.49-58
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• 2021

In the Paleoclimate Modeling Intercomparison Project phase 4 (PMIP4), various experiments for quaternary climatic change are being carried out along with the Coupled Model Intercomparison Project phase 6 (CMIP6). With the CMIP6 preindustrial climate experiment (piControl), the equilibrium climate simulations of 6 ka Holocene experiment (midHolocene), 21 ka Last Glacial Maximum experiment (lgm), and 127 ka Last Interglacial experiment (lig127k) experiment, and transient climate simulations of 850-1849 Common Era Last Millennium experiment (past1000), 21-9 ka last deglaciation, and 140-127 ka penultimate deglaciation experiment have been carried out under PMIP4 protocols by several modeling groups. In this technical note, important physical parameters and boundary conditions of these Tier 1 experiments and a list of additional Tier 2 and 3 experiments are summarized.

• Language and Information
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• v.19 no.2
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• pp.19-36
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• 2015

The aim of this paper is to investigate the usage of Korean markers -(n)un and -i/ka in editorial texts focusing on information structure. Noun phrases ending with the markers -(n)un and -i/ka were annotated semi-automatically using a corpus obtained from an online newspaper. Two important factors to determine the choice of markers were examined with the annotated data: referential givenness/newness and position in a sentence. Referential givenness and newness were adopted as indicators of information structure, topic and focus respectively. In addition to quantitative analysis, qualitative analysis was conducted on the selected data. The results suggest that both the marker -(n)un and -i/ka could carry a topic and a focus reading. Sentence position also played a crucial role in determining the marker, and the marker -i/ka was used more frequently in a later position of a sentence than the marker -(n)un.