• Applied Microscopy
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• 제25권4호
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• pp.115-123
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• 1995

This study was carried out to observe the functional ultrastructures of photoreceptor cells in frog(Rana catesbeiana) retina using transmission electron microscope. The photoreceptor cells are divided into two types-rod and cone cells-consist of outer and inner segment. The long outer segment of rod cell contains dense stacks of membrane and formed vertical and horizontal folds. The outer segment of cone cell is small, and vertical and horizontal folds are not exist. The electron dense cytoplasm of rod cell contains compact mitochondria, Golgi complexes, and endoplasmic reticula. The inner segment of cone cell shows low electron density and contains a large lipid droplet in the upper part of inner segment. In addition, cone cell contains many mitochondria, Golgi complexes. rough endoplasmic reticula, ribosomes and numerous glycogen particles. It is believed that these ultrastructural characteristics are closely associated with photoreceptive function of photoreceptor cells in frog retina.

• Journal of Photoscience
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• 제9권2호
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• pp.284-286
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• 2002

The inverted retina of the Onchidium dorsal eye (DE) is composed only of ciliary-type photoreceptor cells (CC's). The outer segment (OS) of the CC is a concentric lamellar structure consisting of many modified ciliary membranes and stains positively with anti-$\beta$-tubulin antibody. Near the base of the OS there are about 30 basal bodies each connecting individually to a cilium. The cilia are rod-shaped at the base, progressing upwards to a flattened sheet-like shape with increasing surface area. Three-dimensional analysis on serial sections demonstrates the ladle-shape of a modified cilium. Many modified cilia wrap around each other like the leaves of a cabbage. Nine pairs of microtubules (MT's) are located regularly in a ring at the base of the cilium, gradually losing their regular arrangement towards the periphery, where they separate into two subgroups that are contained within two swollen portions of a modified cilium. Within the CC of the Onchidium DE, MT's in the modified cilium exist as two poles extending longitudinally in a thin expanded ciliary membrane. This arrangement may support the photoreceptive OS and serve to maintain its structural integrity.

• Journal of Photoscience
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• 제9권2호
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• pp.275-277
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• 2002

We have recently found that a detergent-resistant raft like membrane (DRM) can be prepared from bovine rod outer segment membranes as a low-density buoyant fraction in sucrose density gradient ultracentrifugation. G protein (transducin) and its effector enzyme (phosphodiesterase: PDE) drastically change their affinities to DRM in the process of phototransduction. We report here that the recruitment of transducin and/or $^2$PDE to DRM has close relationship with their states in signal transduction. Active T$\alpha$/PDE-complex has a high affinity to DRM, whereas inactive transducin, or inactive PDE are excluded from DRM. Active T$\alpha$/PDE-complex seems to bind to a GTPase activating protein (GRS9) in multi- protein complexes localized on DRM. Physiological significance of the multi-protein complex on the raft-like membrane in vertebrate phototransduction would be discussed.

• Plant Resources
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• 제3권3호
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• pp.223-225
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• 2000

A new forma, Cremastra appendiculta Makino f. albiflora B. Kil, f. nov. is described from Naejangsan, Jeollabuk-do, Korea. It is easily distinguished from C. appendiculata by having light white-green flower of outer perianth segment and white color of inner perianth segment of the flower.

• Animal Systematics, Evolution and Diversity
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• 제22권1호
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• pp.1-11
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• 2006

Three new species of Kelleria are described based on the females from the invertebrate burrows in the Port Seogwipo, Jeju Island, Korea. These species possess in common no process on the inner margin of the free segment of leg 5. Kelleria grandisetiger n. sp. possesses a large seta on lateral sides of the genital double-somite and a small thumb-like process near base of the free segment of leg 5. Kelleria undecidentata n. sp. possesses the elongated free segment of leg 5 which is more than four times as long as wide and 11 teeth on the distal margin of the second maxillary segment. Kelleria portiviva n. sp. possesses one seta and one distinct spine on the distal margin of the free segment of leg 5, ten or 11 teeth on the distal margin of the second maxillary segment, and a tuft of spinules on the convex outer comer of mandible.

• Animal cells and systems
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• 제14권4호
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• pp.351-360
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• 2010

A new species of the Cletopsyllidae belonging to the genus Isocletopsyllus Huys and Lee, 1999 is described from the materials collected from subtidal sandy bottoms at Jeju Island and Ulleung Island, Korea. So far, only two species of the genus Isocletopsyllus, viz. I. tertius (Por, 1964) from Israel and I. quartus (Soyer, 1966) from Banyuls-sur-Mer (France) are recorded, both from the Mediterranean Ocean. The new species can be clearly distinguished from its congeners by the combination of the following characters: (1) female antennule with a large process on the outer margin of first segment, (2) caudal rami with a bulbous proximal inner expansion, and shorter than those of other species (about four times long as wide in the new species), (3) second segment of P1 exopod with a short rod-like inner seta, (4) sexual dimorphism presented in the second endopodal segment of male P2, not in exopod of P4, and (6) female P5 with a very long exopod with very short second outer seta. A table comparing the modifications of swimming legs in the family Cletopsyllidae Huys and Lee, 1999 is presented. This is the first record of this family from Korea.

• Animal Systematics, Evolution and Diversity
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• 제35권3호
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• pp.114-122
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• 2019

A new species belonging to the genus Cyclopinopsis Smirnov, 1935 (Cyclopinidae) is described from Korea, as the third species of the genus. Specimens were collected by washing the subtidal sediments off Dokdo Island in the East Sea and the intertidal sands at Baegripo beach, Taean Peninsula on the Yellow Sea coast. Cyclopinopsis deformata n. sp. is characteristic and distinguished from its two congeneric species currently recognized, C. curticauda Smirnov, 1935 and C. brasiliensis Herbst, 1955 in having a deformed seta at the outer distal corner of the third exopodal segment of leg 4. The seta is supposed to be deformed from an outer spine on the third exopodal segment of leg 4, which has been known as completely lost in the genus until now. A character comparison table of the three species and a key to species of the genus Cyclopinopsis are provided herein.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1100-1103
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• 1987

In this paper, we report a method for the primitive segments extraction from printed Korean characters without thinning as a preliminary stage to design an efficient recognition system. The primitive segments are defined by fundamental subpatterns which are vertical(I), right sloping(/), left. sloping(\). horizontal(-), and circular segment(o). The circular segment among the five kinds of segment is different from the others in geometrical properties. Therefore, at first, the circular segment is extracted by using the closed circle of the inner boundary and the geometrical characteristics of its outer. Next, linear segments are separated from the character pattern by means of a directional coding method. Finally, primitive segments are extracted from each set of linear segments by using a projection profile which involves the fact whether the segment has branches or not. The experimental results show that this method reduces computation time and storage space in comparision with the existing methods.

• Journal of Magnetics
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• 제21권1호
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• pp.110-114
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• 2016

Magnetic couplings are widely used in various industrial applications because they can transmit magnetic force without any mechanical contact. In addition, linear couplings have many advantages. For example, they do not need to convert rotary motion to linear motion. This paper shows an analytical analysis of tubular type linear magnetic couplings (TLMCs) with a Halbach array magnetized permanent magnet (PM). An analytical method for magnetic fields owing to PMs is performed by using magnetic vector potential as well as Poisson and Laplace equations. Then, the magnetic force is calculated by using the Maxwell stress tensor. The analytical analysis results were compared with finite element method (FEM) results. In addition, we predicted the magnetic force characteristic according to design parameters such as the iron core thickness, inner PM thickness to -outer PM thickness ratio, PM segment ratio of the axial magnetized PM segment and radial magnetized PM segment, and various pole numbers.

• 한국수산과학회지
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• 제29권3호
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• pp.409-413
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• 1996

한국 연안에서 Paracalanus parvus로 분류되어졌던 종에 대한 분류학적인 재검토를 하였다. 그 결과 한국연안에서 Paracalanus parvus로 분류되어져 왔던 종은 Paracalanus parvus와 Paracalanus indicus, 2종인 것으로 밝혀졌다. 이 두 종의 형태학적 특징 중 가장 뚜렷한 차이는 제$2\~4$유영지였다. Paracalanuss parvus는 제$2\~4$유영지 외지 세번째 마디절 외연 말단부에 거치가 없으며, 제1기절에는 극침이 있다. P. indicus는 제2, 3유영지의 외지 세번째 마디절 외연 말단부에는 거치가 있으나, 제4유영지에는 없다. 또한, 제1기절에 극침이 있다.