• 한국수산과학회지
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• 제46권4호
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• pp.467-487
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• 2013

Long-term and systematic monitoring of phytoplankton is important, as phytoplankton serve as indicators of water quality status in aquatic environments. In the present study, the plankton community structure of the Nakdong River estuary over the past 30 years was investigated by literature survey to provide references for the occurrence of planktonic species. A total of 876 species from 18 taxonomic lineages were reported and, among them, 569 species were identified to occur seasonally at the Mulgeum, Seonam and Eulsukdo sites. Diatoms and chlorophytes were dominant in the microscopic studies. The 54 species at the Mulgeum and the 96 species at the Eulsukdo sites have not been reported since the river barrage construction in 1987. The majority of reports speculate that there has been a change in the aquatic environment, particularly the plankton community structure, due to operation of a river barrage since 1987.

• 한국결정성장학회지
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• 제6권3호
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• pp.368-376
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• 1996

균일한 조성과 doping 효과를 얻을 수 있는 floating zone(FZ)법으로 조화용융조성의 undoped $LiNbO_{3}$ 및 5 mol%의 MgO 또는 ZnO를 각각 첨가한 $LiNbO_{3}$ 단결정을 육성하였다. 결정성장시 최적성장조건을 실험적으로 확립하였으며, 결정내에 존재하는 domain 구조, 전위구조, slip band, 미세쌍정등의 결함구조를 조사 및 분석하였다.

• Coupled systems mechanics
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• 제5권4호
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• pp.355-369
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• 2016

Changes in chemical structure have profound effects on the physical properties of epoxy-based materials, and eventually affect the durability of the entire system. Microscopic structural voids generally existing in the epoxy cross-linked networks have a detrimental influence on the epoxy mechanical properties, but the relation remains elusive, which is hindered by the complex structure of epoxy-based materials. In this paper, we investigate the effect of structural voids on the epoxy-based materials by using our developed mesoscale model equipped with the concept of multiscale modeling, and SU-8 photoresist is used as a representative of epoxy-based materials. Developed from the results of full atomistic simulations, the mesoscopic model is validated against experimental measurements, which is suitable to describe the elastic deformation of epoxy-based materials over several orders of magnitude in time- and length scales. After that, a certain quantity of the structure voids is incorporated in the mesoscale model. It is found that the existence of structural voids reduces the tensile stiffness of the mesoscale epoxy network, when compared with the case without any voids in the model. In addition, it is noticed that a certain number of the structural voids have an insignificant effect on the epoxy elastic properties, and the mesoscale model containing structural voids is close to those found in real systems.

• 미생물학회지
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• 제17권1호
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• pp.1-15
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• 1979

Mycoplasma pneumoniae strain CL-s attached to broth-covered surfaces was examined sequentially during growth from single cells for morphologic and ultrastructural changes using several different electron microscopic techniques. Changes in morphology revealed both round and spindle shapes and observation of cell transitions suggested some type of morphological cycle. The round to-ovoid cells observed in the early stages of growth appeared to be viable, and morphologically and ultrastructurally different from the spherical fors which were produced during the latter stage of growth. The spindle segments were detected appeared to be structurally the same as the terminal cored structure seen in thin sections and may be a growing point or an attachment site of the cell. A tubular structure was observed in the core of the terminal structure and a microtubule-like element appeared to bridge between some spindle segments. A matrix sunstance was observed around single cells as well in the intercellular space of the colonies prepared by critical point metrical triple-layered cytoplasmic mermbranes, surfaces, of which appeared to be structurally different each other, were observed in young cells, whereas symmetrical and thicker membranes were seen in older cells. Small bodies were found in 4d or older cultures and did not appear to contain any internal structures or an easily detectable unit membrane.

• Journal of the Korean Wood Science and Technology
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• 제47권5호
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• pp.617-632
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• 2019

This study aimed to investigate the anatomical structure and fiber quality of four lesser-used wood species namely Benuang (O. sumatrana), Duabanga (D. moluccana), Pisang Merah (H. hellwigii), and Terap (A. odoratissimus). This study evaluated its suitability for raw material in pulp and paper manufacturing. The anatomical structure was observed macro- and microscopically. Macroscopic structures were observed directly to the wood samples, while microscopic characteristics were observed through microtome specimens. Fiber dimension was measured through macerated specimens and fiber quality was analyzed following the Rachman and Siagian's method. Results showed that these four timber species have similarity in the indistinct growth ring, diffuse porous in a radial pattern, rounded solitary vessel outline, 1 to 3 cells of ray width, deposits within the rays, fiber length, and cell wall thickness. Differences were found on vessel diameter, vessel grouping, vessel frequency, tyloses existence, type of axial parenchyma, and ray height. Based on fiber length and its derived values, the wood fibers of all species studied are suitable for pulp and paper manufacturing. They belong to the II quality class. The produced pulp and paper would have good quality, especially in tensile, folding, and tear strength. To promote their utilization, silviculture aspect of these four species has to be well understood.

• Applied Microscopy
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• 제52권
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• pp.13.1-13.6
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• 2022

Microscopic structure of skin in two amphibious mudskipper fish; Boleophthalmus dussumieri Valenciennes, 1837 (B. dussumeri) and Periophthalmus waltoni Koumans, 1941 (P. waltoni) were investigated in relation to their lifestyle. The general structure of skin is the same among the two species. Epidermis in B. dussumeri was thicker significantly than P. waltoni. The dermal bulges were only well developed in the skin of B. dussumeri. Mucous cells were absent in the epidermis of P. waltoni but present in B. dussumeri. Both B. dussumeri and P. waltoni have well-developed swollen middle cells as a shared epidermal feature. The thickness of the middle cell layer of the epidermis in B. dussumeri was significantly greater than in P. waltoni. Capillaries in the dorsal and ventral parts of the body are more closely distributed to the epidermal surface in P. waltoni than in B. dussumeri. The diffusion distance in the dorsal epidermis of P. waltoni was less than that in the ventral epidermis of B. dussumeri. A comparative examination of the skin of mudskipper species suggests that, due to the more terrestrial lifestyle adopted by P. waltoni, the skin contributes more to respiration.

• 한국동물학회지
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• 제35권2호
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• pp.149-160
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• 1992

Using the protein A-gold complex, the mvoabrillogenesis and actin localization of cultured myoblast were invastisated. In the superstructural changes of mvogenic cell during differentiation, pectoral myoblasts contained large nucleus and numerous ribosomes but no myofibrils during the first 24 hr of cultures. Mvoblast initiated to differentiate at 3-day of culture contained the primitive myofibrillar structure. At 96 hr of culture, the mvofibrillar structure showed reletively discernable Z band but pools defined A, H and M bands. The feature of sarcomeric structure showed more defined form at cultur 5 day. In the aspect of actin localization, actin wvas diffusely detected throughout the cytoplasm of myogenic cell and nucleus during the proliferating stage. At 72 hr of culture, with the appearantc oi primitive mvofibrils, gold particles were observed in surrounding of myofibrils but still presented in overall of cytoplasm, especially in the surface and lumen of endoplasmic reticulum. With the gradual increase of culture time, local distribution of actin was readily detected within cytoplasm. In the 5-day specimen of cultures, gold particles precisely indicate the sites of actin localifation within the sarcomere. These results indicate the time of onset of myofibrill appearance and the biosynthetic and incorporation pathway of actin molecules into sarcomeric structure during myofibrillogenesis. Thus, in the present study, the first mvoabrillar structure was detected at culture 3 day, and the initiation of assembly into a typical sarcmeric structure was observed at culture 5 day. It seems, however, that the course of events on myofibrillogenesis of cultured myoblasts can be changed with great dependence of culture conditions including the number and groluth rate of mononucleated mvoblasts after seeding although the fundamental process shows identical appearances.

• 한국지능시스템학회논문지
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• 제24권4호
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• pp.355-359
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• 2014

본 논문은 단순한 후반부 구조를 가진 퍼지 모델을 계층적 구조로 결합한 퍼지 패턴 분류기를 제안한다. 계층적 구조를 가진 퍼지 패턴 분류기의 기본 구조는 단순한 후반부 구조를 가진 퍼지 모델을 사용하여 전체 패턴 분류기의 구조적 복잡성을 높이지 않도록 설계 하였다. 입력공간을 계층적으로 분할하기 위하여 대표적인 퍼지 클러스터링 알고리즘인 Fuzzy C-Means clustering 기법을 이용하였다. 분할된 퍼지 입력 공간의 하위 구조를 분석하기 위하여 conditional Fuzzy C-Means 클러스터링 기법을 이용하였다. 계층적으로 분할된 퍼지 입력공간에 간단한 구조를 가진 퍼지 패턴 분류기를 적용하여 계층적 구조를 가진 패턴 분류기를 설계한다. 계층적으로 퍼지 모델들을 결합함으로써 입력 공간의 정보 분석을 거시적인 관점에서 시작하여 세부적으로 분석이 가능하게 되었다. 제안된 퍼지 패턴 분류기의 성능을 평가하기 위하여 다양한 기계 학습 데이터를 사용하였다.

• 대한의생명과학회지
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• 제12권3호
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• pp.281-287
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• 2006

Cigarette smoke causes atypical structure of pulmonary and oxidative damage. Therefore, we carried out to determine if exposure to cigarette smoke alters pulmonary structure and anti-oxidant related enzyme in a animal model, when natural product extracts using by Nebulizer. The rat were divided into four groups: $H_2O-treated$ (Control), natural product (Camellia sinensis) extracts-treated (CS), natural product extracts-treated with cigarette smoke-exposed (CS+SM) and cigarette smoke-expose (SM). All groups are similar to Control group in weight, but SM group is lower than the other groups. Microscopic image of the pulmonary structure in SM group showed deleterious alterations in the morphology, but the other groups are maintained in normal structure. In anti-oxidant related enzymes, SOD (superoxide dismutase) and catalase, SM group represents the lowest enzyme activity among all groups. But G6PD (glucose-6-phosphate dehydrogenase) and LPO (lipid peroxidation) is SM group represents the highest enzyme activity among all groups. These result indicate that the natural product extracts is an efficient tissue protective substance against smoke-induced lung injury.

• 대한수의학회지
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• 제12권2호
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• pp.153-164
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• 1972

With an effort to clarify the nature of the azurphil granules which occasionally occur in the circulating lymphocytes, these granules were investigated by examining smear of the peripheral blood of the chikens in various stage of the individual growth and after injection of methylene blue and gentian violet. In addition, the fine structure of these granules were also investigated. The results were: 1. These granules were first occurred in the lymphocytes just after their hatching (0.004%). The proportion of lymphocytes containing these granules were increased with their growth and in adult chicken its occurrence was higher than mammals. 2. Marked variations in its fine structure, particularly in its size and cotents, were noted but they were believed to belong to categories of lysosome of de Duve. 3. Lymphocytes containing azurophil granule were increased after injection of the non-immunogenic substances, such as gentian violet and methylene blue. 4. From the above results, chicken is bettor animal to study theme granules because of its higher occurrence. They are believed to have intimate relationship with bodily cellular reaction against the foreign materials because they are increased after non-immunogenic stimuli.