• Economic and Environmental Geology
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• v.54 no.1
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• pp.1-19
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• 2021

This study reports the Ar-Ar dating results for the volcanic rocks from small volcanoes(oreum) of the Hallasan Nature Reserve. According to the age of 40Ar/39Ar, the volcanic activity of the Hallasan Natural Reserve was started from about 192 ka ago. The basaltic trachyandesite and trachyte located in the Y valley near the Eorimok in the western part of the Hallasan Natural Reserve represent an age of about 191~192 ka, showing the oldest record of volcanic activity in the Hallasan Natural Reserve. In the Hallasan Natural Reserve, the small volcanoes older than 100 ka are Y Valley in Eorimok area (192±5 and 191±5 ka), Dongsu-Ak (184±19 ka), Mansedongsan (153±5 ka), Janggumok-Orum (135±6 ka), Eoseungsaengak (123±9 ka), Samgagbong (105±2 ka). And the small volcanoes younger than 100 ka are Witbangae-Oreum, Seongneol-Oreum, Muljangol, Yeongsil, Bori-Ak, Witsenueun-Oreum, Witsejokeun-Oreum, Heugbuleun-Oreum, Bangae-Oreum, Albangae-Oreum, Witsebuleun-Oreum, Baengnokdam, Nongo-Ak. According to the eruption of trachytes, the Hallasan Natural Reserve can be interpreted as having about 8 volcanic activities. Among them, 4 volcanic activities are related with the formation of trachyte dome, such as Wanggwanneung, Samgakbong, Yeongsil, and Baengnokdam, and 4 volcanic activities are related with flow or dyke of trachyte. The volcanic activity at the Hallasan Natural Reserve was started from northwest area, to in the southern area, and in the eastern area, and finally volcanic activity related to the formation of Baengnokdam.

• Parasites, Hosts and Diseases
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• v.39 no.2
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• pp.161-170
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• 2001

We conducted both the small subunit ribosomal DNA (SSU rDNA) polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and mitochondrial (mt) DNA RFLP analyses for a genetic characterization of Acanthamoeba isolates from contact lens storage cases of students in Seoul, Korea. Twenty-three strains of Acanthamoeba from the American Type Culture Collection and twelve clinical isolates from Korean patients were used as reference strains. Thirty-nine isolates from contact lens storage cases were classified into seven types (KA/LS1 , KA/LS2, KA/LS4, KA/LS5, KA/LS7 KA/LS18, KA/LS31). Four types (KA/LS1 , KA/LS2, KA/LS5, KA/LS18) including 33 isolates were regarded as A. castellanii complex by riboprints. KA/LS1 type was the most predominant (51.3%) in the present survey area, followed by KA/LS2 (20.9%), and KA/LSS (7.7%) types. Amoebae of KA/LS1 type had the same mtDNA RFLP and riboprint patterns as KA/E2 and KA/E12 strains, clinical isolates from Korean keratitis patients. Amoebae of KA/LS2 type had the identical mtDNA RFLP patterns with A. castellanii Ma strain, a corneal isolate from an American patient as amoebae of KA/LS5 type, with KA/E3 and KA/E8 strains from other Korean keratitis patients. Amoebae of KA/LS 18 type had identical patterns with JAC/E1, an ocular isolate from a Japanese patient. Three types , which remain unidentified at species level, were not corresponded with any clinical isolate in their mtDNA RFLP and riboprint patterns. Out of 39 isolates analyzed in this study, mtDNA RFLP and riboprint patterns of 33 isolates (84.6%) were identical to already known clinical isolates, and therefore, they may be regarded as potentially keratopathogenic. These results suggest that contact lens wearers in Seoul should pay more attention to hygienic maintenance of contact lens storage cases for the prevention of Acanthamoeba keratitis.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.456-460
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• 2011

This study was carried out to compare the pattern of mutant variation and to evaluate the characteristics of mutants obtained by gamma irradiation in rose 'Kardinal'. Forty four rooted cuttings of 'Kardinal' were irradiated at 70 Gy gamma-ray dose from a $^{60}Co$ source to induce mutants in 2002. The irradiated plants were planted in field, and observed spotting of petal color mutants from 2002 to 2004. Four different kinds of mutant twigs with each different color flower were obtained from the irradiated 'Kardinal' with red petal. After being identified to be a stable mutant from 2004 to 2008, each mutant line propagated by cutting was hydroponic-cultured to evaluate the characteristics in the greenhouse from 2008 to 2009. Four mutant lines obtained from 'Kardinal' with red petal (Red group, 44A, 45B) include KA1 with light pink petal (Red group, 55B-55D), KA2 with pink petal (Red group, 63A-63B), KA3 with deep pink (Red purple, N57A-N57C), and KA4 with orange red (Red group, 43A-43B). Diameters of each flower in four mutant lines were different from 'Kardinal'. The line KA1 was 9.5 cm wide, and it showed the smallest diameter when compared to other mutants. While the line KA2 was the largest one with 12.5 cm 'Kardinal'. Petal number per flower was also variable among the mutants. The line KA2 had 39.8 petals being the largest number among the mutants, while the line KA1 was the lowest one compared to 35.5 petals of 'Kardinal'. Petal color was measured by using colorimeter. Brightness (L) measured at each petal of four mutants increased more than 'Kardinal'. CIE Lab values, a and b decreased more than 'Kardinal' at the petal color of three mutants except the line KA4. Characteristics of shoot, leaf, etc. from four mutants were also different from the ones of 'Kardinal'. The line KA1 was shortest in shoot, node and peduncle length, and lowest in prickle number. The reverse side of leaves was reddish green color in 'Kardinal' as well as the line KA4, but green color in the line KA1, KA2, and KA3.

• Parasites, Hosts and Diseases
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• v.45 no.1 s.141
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• pp.1-9
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• 2007

The endosymbionts of 4 strains of Acanthamoeba(KA/E9, KA/E21, KA/E22, and KA/E23) isolated from the infected corneas of Korean patients were characterized via orcein stain, transmission electron microscopic examination, and 16S rDNA sequence analysis. Double membrane-bound, rod-shaped endosymbionts were distributed randomly throughout both the trophozoites and cysts of each of Acanthamoeba isolates. The endosymbionts of KA/E9, KA/E22, and KA/E23 were surrounded by electron-translucent areas. No lacunae-like structures were observed in the endosymbionts of KA/E21, the bacterial cell walls of which were studded with host ribosomes. Comparative analyses of the 16S rDNA sequences showed that the endosymbionts of KA/E9, KA/E22 and KA/E23 were closely related to Caedibacter caryophilus, whereas the KA/E21 endosymbiont was assigned to the Cytophaga-Flavobacterium-Bacteroides(CFB) phylum. In the 4 strains of Acanthamoeba, the hosts of the endosymbionts were identified as belonging to the Acanthamoeba castellanii complex, which corresponds to the T4 genotype. Acanthamoeba KA/E21 evidenced characteristics almost identical to those of KA/E6, with the exception of the existence of endosymbionts. The discovery of these endosymbionts from Acanthamoeba may prove essential to future studies focusing on interactions between the endosymbionts and the amoebic hosts.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.593-600
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• 2016

The paper presented investigates the effects of kaolinite on strength properties of alkali-activated multi-component cement. The binders of this study was blended of ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF) and kaolinite (KA). In this study, the specimens of combination of 20%~70% GGBFS, 10%~60% FA, 10% SF (constant ratio) and 10%~50% KA binder were used for strength properties tests. The water/binder ratio was 0.5. The binders (GGBFS + FA + SF + KA) was activated by sodium hydroxide (NaOH) and sodium silicate ($Na_2SiO_3$) was 10% by total binder weight (10% NaOH + 10% $Na_2SiO_3$). The research carried out is on the compressive strength, water absorption, ultrasonic pulse velocity (UPV) and X-ray diffraction (XRD). The compressive strength decreased as the contents of KA increase. One of the major reason for this is the low reactivity of KA compared with other raw materials used as precursors such as GGBFS or FA. The presence of remaining KA indicates that the initially used quantity has not fully reacted during hydration. Moreover, the results have indicated that increased of KA contents decreased UPV under all experimental conditions. The drying shrinkage and water absorption increased as the content of KA increase. Test result clearly showed that the strength development of multi-component blended cement were significantly dependent on the content of KA and GGBFS.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.41-47
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• 2007

The first geostationary satellite made by Korea, COMS, has the three different payload ; Meteorological sensor, Oceanographic sensor and Ka-band communication payload. There are Meteorological & Ocean Data Communication Subsystem(MODCS) and Telemetry, Command and Ranging Subsystem(TC&R) as other RF radiation sources. MODCS transmits and receives Meteo and Ocean measurement data from/to earth using L-band and TC&R using S-band. The Ka-band communication payload will provide high-speed multimedia services and communication services for natural disaster such as prediction, prevention, and recovery services in the government communications network.Ka-band beacon is for the earth antenna pointing and the experiment of rain fading. This paper gives the analysis results about the mutual radiation effect on Ka-band communication payload, Ka-band beacon, MODCS and TC&R. Up/Down link power and coupling factor including the geometrical position and distance of antenna, filter rejection and degradation factor due to the different polarization are considered. The results show MODCS and TC&R are compatible for Ka-band communication payload and Ka-band beacon does not interfere with MODCS and TC&R normal operation.

• Korean Journal of Acupuncture
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• v.27 no.2
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• pp.49-56
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• 2010

목적 : 뇌의 신경세포 증식은 해마 치상회와 뇌실하영역에서만 나타나는 현상이다. Kainic acid(KA)를 이용한 간질 동물모델을 연구하던 중 침이 해마 치상회의 신경세포증식을 촉진하는 현상을 발견하여 이를 보고하고자 한다. 방법 : 수컷 ICR계 생쥐를 Saline(n=8), KA(n=8), KA+Acu(n=8)의 세 군으로 나누고, 모든 생쥐들에게 KA 주입 3일 전부터 1일 1회씩 5'-bromodeoxyuridine(BrdU)을 3일간 주입하였다. Saline군에는 멸균된 생리식염수를 뇌실 내에 주입하였고, KA군 및 KA+Acu군에는 $0.1{\mu}g$의 KA를 뇌실 내에 주입하였으며, KA+Acu군에 속한 쥐들에게는 KA 주입 2일전, 1일전, 주입 직후에 양쪽 소부(少府)(HT8)에 자침하였다. KA 주입 3시간 후 쥐의 뇌를 적출하고 해마 치상회부위의 BrdU 및 neuropeptide Y (NPY)의 발현을 측정하였다. 결과 : 소부(少府) 자침이 KA의 독성으로 인한 신경세포의 파괴를 줄여주었으며, BrdU 양성 세포 및 NPY를 유의하게 증가시켰다. KA 주입시 세포증식이 일어나긴 하나, 3시간 안에는 거의 일어나지 않는다. 결론 : 소부(少府) 자침이 해마 치상회의 신경세포증식을 촉진하며, 이는 KA의 효과가 아닌 KA 투여 전 소부(少府) 자침으로 인한 것으로 사료된다.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.75-81
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• 2010

COMS (Communication, Ocean and Meteorological Satellite) is the multi-purposed Korean geostationary satellite funded by four Korean government ministries, and is to supply communication services, ocean and weather observation for 7 years. As part of COMS, development of Ka band communication payload composed of microwave switching transponder and multi-horn antenna is sponsored by KCC (Korea Communications Commission) and developed by ETRI (Electronics and Telecommunications Research Institute). The purpose of Ka Payload development is to acquire space proven technology of Ka payload and to exploit advanced multimedia communication services. This paper aims to study development technology of Ka payload system through whole process of ETRI project. Also application of Ka payload will be dealt in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.7
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• pp.1038-1043
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• 2002

The demand for multimedia service using Ka-band satellite communication are growing rapi이y. So, in this paper, we have analyzed rain attenuation with typical model, and proposed prediction model of rain attenuation in high frequency(over 20[GHz]). Path loss model by rain attenuation is based upon rain rate of representative region(6 cities). Proposed prediction model of rain attenuation and parameter of satellite link can be available for the Ka-band satellite communication.

• Language and Information
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• v.19 no.2
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• pp.37-53
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• 2015

It has been widely accepted that Korean -i/ka, known as the nominative marker, can give rise to exhaustivity effect. However, it has been rarely discussed and still remains unclear how and why the particle can convey exhaustivity. The purpose of this paper is to shed light on this issue, based on Kim's (2014) analysis of the function of -i/ka. The main claim is that the exhaustivity expressed by -i/ka is a pragmatic effect derived from the interaction of the function of -i/ka, namely, unique specification, and the existence of alternatives to the denotation of an -i/ka-marked phrase in discourse context. Thus, the nature of the exhaustive implicature induced by -i/ka is not conventional but conversational.