• Korean Journal of Microbiology
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• v.32 no.3
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• pp.202-207
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• 1994

A mutant strain PRM1 defective in light-activated heterotrophic growth was isolated from Synechocystis sp. PCC 6803. PRM1 could be grown at growth rate equivalent to Synechocystis 6803 under mixotrophic growth conditions. However, PRM1 could not be grown under light-activated heterotrophic conditions, in which a daily pulse of light for 5 min was given. These results suggest that PRM1 is not defective in heterotrophic metabolism, but in the transduction pathway of light signal essential to the growth. Plasmid patterns, absorption spectra of whole cells, and the exterior and interior structures of PRM1 were similar to those of Synechocystis 6803, except that PRM1 could not produce amorphous slime holding cells together.

• Korean Journal of Ichthyology
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• v.28 no.2
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• pp.67-71
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• 2016

Two Korean Rhodeus bittering fishes are known as having a unique reproduction system that the female deposits its egg inside freshwater mussels. Among them, R. ocellatus and R. uyekii show an ecological difference in feeding items and micro-habitat. Through a light microscope, the visual cells of the retina in the two species were investigated to get information between vision and environment related with habitat. The two fishes' eyes are spherical and R. ocellatus has relatively larger eyes. For the two species, the visual cells of the retina consisted of long single cones, short single cones, unequal double cones and rods. In the cones, all show a row mosaic pattern. Although the two species have a different micro-habitat in the wild, the component of the visual cells was very similar to each other.

• Parasites, Hosts and Diseases
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• v.31 no.4
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• pp.347-352
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• 1993

Six early third-stage larvae of Gnnthostoma nipponicum were recovered from the muscle of 376 loaches, Misgurnw anguiILicnudatus, imported from China. They were 614 × 114㎛ in average size, almost colorless except brownish intestine, and encircled by about 229 transverse rows of minute cuticular spines. Their head bulbs provided with 3 rows of hooklets, of which average number were 34.5 on the first, 36.7 on the second and 39.7 on the third. According1y, it is revealed that the Chinese loach is a natural second intermediate host of G. nipponicum and G. nipponicum has been distributed somewhere in China. This parasite may infect human when the imported loaches are consumed raw.

• Parasites, Hosts and Diseases
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• v.26 no.3
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• pp.179-188
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• 1988

The life cycle of Fibricola seoulensis was studied in the laboratory and in the field, with special interests in the larval developments within the eggs and in the intermediate hosts. The first emergence of miracidia after incubation of eggs in 26C water began on the ninth day. The miracidia, elongate and cylindrical shape, had epidermal plates in the formula of 6, 9, 4 and 3, with two pairs of flame cells and lateral processes. A kind of fresh water snail, Hippeutis (H.) cantori, was found to shed furcocercous cercariae from the 13th day after experimental challenge with miracidia while Physa acute failed to shed. The same kind of snail collected from the field also shed the same cercariae. The cercariae were equipped with 2 pairs of penetration glands and 5 pairs of fame cells. The tadpoles of Rana nigromaculata were found susceptible to experimental infection with the cercariae. The same kind of tadpoles collected from various areas were also found naturally infected. The metacercariae in the tadpoles which were infected experimentally became infective to the definitive host in 21 days. The metacercariae were located free in the body cavity of tadpoles, and attained sexual maturity in rats in 7 days. The present study successfully followed the complete life cycle of F. seoulensis and found that it is possible to maintain the life cycle in the laboratory.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.161-164
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• 1999

본 논문에서는 표적 추적 시스템에서 센서 어레이에 입사되는 표적신호에 대한 센서 출력 신호간의 지연시간 추정(TDE:Time Delay Estimation)을 위해 백색상호 상관법(CSP:Cross-Power Spectrum Phase Analysis)을 이용한다. 그러나 음파의 다중경로 전달특성 및 배경잡음의 영향으로 인해 CSP계수는 많은 클러터(Clutter)를 포함하게 되고 결국 방위 추정 오차의 요인이 된다. 따라서 센서 어레이 중심좌표를 기준으로 대칭 배열된 센서쌍(Pair)에 대한 CSP계수를 동기가산 하여 실제 표적 방향 이외의 방향정보를 제거하는 방법을 제안한다. 시간에 따라 각도를 변침하는 표적에 대한 표적기동분석 (BOTMA:Bearings Only Target Motion Analysis)을 위해 매 관측시간마다 동기가산을 행한 CSP결과를 누적하여 방위각 궤적을 형성하였을 때 시간 Window에 따라 약간의 차이는 있지만 약 10dB의 궤적 추적 성능을 확인하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1131-1140
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• 2004

In this paper, we proposed a flate-plate antenna employing semi-annular slots for satellite broadcast reception. The radiating element of the antenna is dual annular slots fed by a strip dipole, which have a wider bandwidth than the rectangular slot. A $16{\times}16$ array antenna is designed using stripline T-junction power dividers. Measurements of the fabricated antenna show a gain of 28.0$\~$29.5 dB in 11.7$\~$12.8 GHz frequency range.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1607-1613
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• 2008

We investigated the miniaturized free electron laser(FEL) module based on microcolumn. The miniaturized FEL is composed of two parts: electron generation part and radiation emission part. The radiation emission part, called wiggler, consists of a grid plate. While the electrons are passing through the wiggler, electron trajectory shows sinusoidal curve caused by the periodically applied voltage on the grid, and then it give rise to radiation emission. We analyzed the wiggler parameters, grid width, depth, period, applied voltage and the pair wiggler space using 2-D simulation tool.

• Parasites, Hosts and Diseases
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• v.26 no.1
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• pp.33-38
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• 1988

A coiled nematode, which was removed surgically from a Thai woman, was consulted to the authors in July, 1987. She was known to surfer from meningoencephalitis since she was in Thailand. Numerous eosinophils were detected from her CSF. The worm was 12.3mm long and 0.9mm wide. It had a head bulb beset with eight rows of spines, a cervical constriction, esophagus, cervical sacs, dark intestine and testis, Cuticle of anterior half of the worm was covered with numerous spines. The spines at anterior part was stout and had 3∼4 tips, but they became slender, shorter, single tipped and sparser and finally they disappeared posteriorly. Cuticular spines reappeared at tail which had 4 pairs of pedunculated papillae. By above morphological characteristics, the worm was identified as an adult male of Gnathostcma spinigerum. The Present case is the first authentic case of imported intracranial gnathostomiasis in Korea, although clinical informations of the case were obtained limitedly.

• Applied Microscopy
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• v.28 no.1
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• pp.39-48
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• 1998

The spermatozoa of bagrid catfish, Pseudobagrus fulvidraco are approximately $76{\mu}m$ in length, and a relatively simple and elongated cell composed of a spherical head, a short middle piece and a tail. The ultrastructure of spermatozoa of P. fulvidraco is characterized by the following features. The acrosome is absent as in most teleost. The round nucleus measuring about $1.67{\mu}m$ in length and diameter is depressed with a deep nuclear fossa. The nuclear fossa, the length of which is about three-fifths of the nuclear diameter, contains the proximal and distal contrioles. The two centrioles are oriented approximately $160^{\circ}$ to each other. The filamentous materials give rise to satellite appendages arranged tangentially from the triplets of the distal centriole and the doublets of the anterior end of the axoneme toward the nuclear envelope. The mitochondria are not fused and their number is 20 or more. They are arranged in two or three layers and two rings within the cytoplasmic collar and surround the axoneme. They are separated from the axoneme by the cytoplasmic canal. The axoneme is of the 9+2 microtubular pattern and has inner but no outer dynein arms. The two lateral fins are in the same plane with the two central microtubules, the doublets 3 and 8, which are ultrastructural characteristics of the sperm tail unlike other siluroids lacking the lateral fins.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1269-1279
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• 2021

Geostationary Ocean Color Imager II (GOCI-II), which are now operated successfully since its launch in 2020, acquires local area images with 12 Level 1B slot images that are sequentially acquired in a 3×4 grid pattern. The boundary areas between the adjacent slots are prone to discontinuity in radiance, which becomes even more clear in the following Level 2 data, and this warrants the precise analysis and correction before the distribution. This study evaluates the relative radiometric biases between the adjacent slots images, by exploiting the overlapped areas across the images. Although it is ideal to derive the statistics from humongous images, this preliminary analysis uses just the scenes acquired at a specific time to understand its general behavior in terms of bias and variance in radiance. Level 1B images of February 21st, 2021 (UTC03 = noon in local time) were selected for the analysis based on the cloud cover, and the radiance statistics were calculated only with the ocean pixels. The results showed that the relative bias is 0~1% in all bands but Band 1 (380 nm), while Band 1 exhibited a larger bias (1~2%). Except for the Band 1 in slot pairs aligned North-South, biases in all direction and in all bands turned out to have biases in the opposite direction that the sun elevation would have caused.