• Journal of fish pathology
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• v.4 no.1
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• pp.1-11
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• 1991

Histopathological changes and methemoglobinemia of the eels (Anguilla japonica) reared at six culture farms in the vicinity of Y$\check{o}$su city were investigated under the conditions of $22.0{\sim}29^{\circ}C$, 4.33~7.33ppm of D.O., pH 6.1~8.2 and 0.03~10.1ppm of nitrite from December, 1989 to June, 1990. All of the eels showed no any abnormal state in action, color and blood, but the eels reared in pH 6.0 had planty of mucus and stickiness on their body surface. Methemoglobin levels were 1.03~9.86% of total erythrocyes in Dec. and 5.05~25.69% in June, and poikilocyte levels were 5.8~30.17% in Dec. and 8.67~74.45% in June. These results indicate the fact that the water management of the culture farms was worse in summer than in winter, even though not good in winter. Hypertrophy was found in the gill, hepatic and kidney tissue of the eels in all the culture farms. In March and June, Fish of all culture farms appeared the detachment of gill lamella epithelium cells, pyknosis and sinusoids of nucleus in the hepatic tissue and hemosiderosis in the kidney tissue. The trend of increase in methemoglobin levels appeared in the fish of culture farms with high nitrite concentration, which didn't appear equally in all the culture farms. However, in the culture farms of pH 6.0, methemoglobin and poikilocyte levels were increased independently of concentration of nitrite, and degeneration in the tissue of the gill, liver and kidney was also appeared.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.11a
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• pp.42-42
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• 2000

패선/구부림 가공은 백판지의 후가공의 일부분으로서 통상적으로 고평량인 백판지를 소비 자에게 맞는 형태로 가공하는 한 공정으로서 접는 공정을 용이하게 하기 위하여 종이 표면 에 패선을 넣어 구부려 접게 되는데 이때 구부리는 면의 표면적의 증가와 내부에서 외부로 향하는 Stress 에 의하여 종이의 표면층이 터지는 현상이 발생하기도 한다.이러한 터짐을 방지하면서 구부립 가공을 하기 위하여 백판지에 요구되는 특성은 여러 가지가 있으며 특히 고평량인 경우에는 종이가 구부러지면서 변형이 크게되는 만큼 외부로 밀리는 힘이 더욱크 게 작용하게 되고 이 힘을 충분히 수용할 수 있는 종이 자체의 강도가 펼요하게 되는데 본 연구에서는 다층판지의 원료특성과 판지특성등이 패션/구부림 가공적성과 연관성을 밝혀내 어 향후 연구방향의 기초를 삼고자 한다. 본 실험에서는 실험실적 결과와 실제 제품에서와의 차이를 최소화 하기 위하여 현장에서 생산되는 백판지를 사용하였으며 백판지의 각층을 구성하는 원료특성과의 상관관계까지 고 려하여 대전공장에서 생산되는 원료의 특성을 분석하고 같은 시간대의 제품과 비교펑가하는 방법을 취하였다. 각각의 원료 특성과 제품특성 (구부러짐 특성) . 공정조건등의 자료를 일정기간 취합하여 S Statisca 를 사용한 통계분석을 하였으며 1차 분석 결과 종이무성에 미치는 영향이 큰 수분 함량과 표면층의 원료구성 (Softwood 함량) 이 일차적으로 영향을 크게 미치며 종이 특성 으로는 CD 방향 터짐과 관련하여 MD 방향 인장, 내절, CD방향 강성등이 상관관계지수 0 0.7 이상으로 비교적 관계가 깊은 것으로 나타나며 인장과 신장율의 곱인 Toughness는 상 대적으로 낮아 터짐 지수로 활용하기는 어려울 것으로 판단되며 또한 신장율도 0.5 수준으 로 나타나며 패선구부러짐에 따른 층간구조변화에 따른 층간결합력이 영향이 있을 것으로 추측은 되었으나 분석결과 0.5 수준인 것으로 나타났다. 또한 CD 방향과 MD 방향의 터짐 성 상관관계도 0.5 이상인 것으로 나타나 섬유배향성도 패선/구부림 가공적성과 관련이 있 는 것으로 나타남으로서 패선/구부림 적성향상은 원료뿐만 아니라 초지공정조건에서도 향상 될 수 있는 것으로 나타났다. 향후 보다 세분화한 분석 및 도공층의 역할이 펼요할 것으로 판단되며 또한 지층구조분석 을 통한 Modeling 도 필요한 것으로 판단된다.

• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.111-117
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• 2000

There were observed the histomorphological alterations such as chloride cell hyperplasia, branchial lamellar epithelial separation, the increased cellular turnover of chloride cells, glomerular shrinkage and blood congestion in rainbow trout (Oncorhynchus mykiss) during the seawater adaptation. The ultrastructure by scanning electron microscope (SEM) indicated that the gill secondary lamella of rainbow trout exposed to seawater, were characterized by rough convoluted surfaces during the adaptation. There were observed a large number of mitochondria with the elongate and well-developed cristae in chloride cells exposed to seawater by transmission electron microscope (TEM). The presence of two mitochondria- rich cell types is discussed with regard to their possible role in the hypoosmoregulatory changes which occur during seawater-adaptation. Glomerulus shrinkage and blood congestion were occurred higher in nephrons of seawater-adapted fish than those living in freshwater. Our findings demonstrated that rainbow trout tolerated moderately saline environment and the increased body weight living in seawater was relatively higher than that living in freshwater in spite of histopathological changes.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.55-63
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• 2000

Studies for tube spin forming have been implemented restrictively compared to spinning process, because of the complex of deformation mechanism. Especially there were not many studies by using FEM(Finite Element Method) for overcoming restriction of upper bound method. In this paper, the tube spinning process is analyzed to produce cylindrical body made by titanium alloy. In analysis, processing parameters was obtained by using upper bound method to consider material properties of titanium alloy and finite element analysis was implemented to investigate the flatness and the elongation of the titanium alloy workpiece by using ABAQUS code. The independent variables are ; material properties of workpiece, angles of roller, reduction of diameter. Three variables, two angles of roller and reduction of diameter are optimized by using the upper bound method. In this method, we can estimate the workable power, working force and reduction of diameter, and also the flatness and the elongation of workpiece by the finite elements analysis using ABAQUS/standard. The results indicates that these variables play a critical factors of spinning process for the titanium alloy and the optimum values of these variables.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.351-363
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• 2009

Two orthogonal joint sets develop well only in sandstone beds in the sandstone-mudstone sequences of Gumi and Dasa outcrops within Cretaceous Gyeongsang Basin. And various joint data are similar in the beds of the same thickness in both outcrops, meaning that the joint sets were homogeneously produced by extensional deformation in the same regional stress field. Most of joints in the sandstone beds are orthogonal to, and confined by bed boundaries, which are believed to be formed by hydrofracturing during consolidation after burial. Two orthogonal joint sets are considered to be almost coeval on the basis of mutual abutting relationship which makes up fracture grid-lock and a product of rapid switching of ${\sigma}_2$ and ${\sigma}_3$ axes with constant ${\sigma}_1$ direction oriented to vertical. The joint sets in the sandstone beds show planar surfaces, parallel orientations and regular spacing, with joint spacing linearly proportional to bed thickness. The spacing distributions of the joints seem to correspond to log-normal to almost normal distribution in most of the beds. But multilayer joints do not display regular spacing and dominant size. Either joint set in this study is characterized by a high level of joint density and a saturated spacing distribution as indicated by the mode/mean ratio values and the Cv(coefficient of variance) values. Joint aperture tends to increase with the vertical length of the joints controlled by bed thickness.

• Applied Microscopy
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• v.30 no.3
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• pp.273-283
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• 2000

To investigate the defensive effect of green tea against the lead toxicity, Sprague-Dewley rats (150 gm) were divided into 5 groups; the control group (A), the group treated with lead for 4 weeks (Group B-1), the group treated with lead and green tea for 4 weeks (Group B-2), the group treated with lead for 8 weeks (Group C-1), and the group treated with lead and green tea for 8 weeks (Group C-2). The lead acetate (500 ppm) was injected two times for one week into the abdomen and green tea solution (3 g/100 ml distilled water) offered freely. The results of histological and biocheical study are as follows; 1. Blood Urea Nitrogen (BUN) were increased in all the tested groups. The Group B-1 was more increased than the Group B-2, and the Group C-1 more than the Group C-2. The values of Alkaline phosphatase (ALP) were also decreased in all the tested groups, as such the former phenomenon. 2 In the Group B-1, some microvilli, mitochondria and rER were modificated on epithelial cell of proximal renal tubules. The cristae of mitochondria were enlarged, microvilli and nucleus were observed normally on the Group B-2. The number of Microvilli, mitochodria and rER were decreased, many lysosomes and irregular nucleus observed in the Group C-1. In the Group C-2, microvilli were modificated slightly and other organelles were observed similary with the Group B-2.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.731-742
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• 2010

Modeling of rubber for design or analysis often requires confusing or complex work because there are a large number of constitutive models to be considered. Some models have few material constants, while others have many. Researchers have to prepare and fit extensive experimental data with caution and discretion. In this paper, we first compared some typical rubber models in which deformation was carried out by stretching up to around eight times the original size. We conclude that continuum-based models and chain molecular models can be used in the study of the small deformation in most engineering applications, but chain molecular models are preferred in the study of the large deformations in most biomaterial applications. As discrimination problems, Treloar's patch and cylindrical balloon stick are tested theoretically and numerically for studying bifurcation. In the case of Treloar's patch, by using the Kearsley's equation, we show that bifurcation exists for continuum-based models but not for chain molecular models. Both models show bifurcation in the cylindrical balloon stick. Therefore, in the analysis of the bifurcation of rubber showed that its existence also depends on the constitutive model selected.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.429-435
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• 2016

Cold stretching(CS) pressure vessels from ASS304 (austenitic stainless steel 304) are used for the transportation and storage of liquefied natural gas(LNG). CS pressure vessels are manufactured by pressurizing the finished vessels to a specific pressure to produce the required stress ${\sigma}_k$. After CS, there is some degree of plastic deformation. Therefore, CS vessels have a higher strength and lighter weight compared to conventional vessels. In this study, we investigate the tensile and fatigue behavior of ASS304 sampled by CS pressure vessels in accordance with the ASME code at cryogenic temperature. From the fatigue test results, we show S-N curves using a statistical method recommended by JSEM-S002. We carried out the fractography of fractured specimens using scanning electron microscopy (SEM).

• The Korean Journal of Petroleum Geology
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• v.1 no.1 s.1
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• pp.15-27
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• 1993

Seismic reflection profiles from the eastern continental margin of Korea delineate three major Neogene sedimentary basins perched on the shelf and slope regions: Pohang-Youngduk, Mukho and Hupo basins. The stratigraphic and structural analyses demonstrate that the formation and filling of these basins were intimately controlled by two phases of regional tectonism: transtensional and subsequent contractional deformations. In the Oligocene to Early Miocene, back-arc opening of the East Sea induced extensional shear deformation with dextral strike-slip movement along right-stepping Hupo and Yangsan faults. During the transtensional deformation, the Pohang-Youngduk Basin was formed by pull-apart opening between two strike-slip faults; in the northern part, block faulting caused to form the Mukho Basin between basement highs. As a result of the back-arc closure, the stress field was inverted into compression at the end of the Middle Miocene. Under the compressive regime, two episodes (Late Miocene and Early Pliocene) of regional deformation led to the destruction and partial uplift of the basin-filling sequences. In particular, during the second episode of compressive deformation, the Hupo fault was reactivated with an oblique-slip sense, which resulted in an opening of the Hupo Basin as a half-graben on the downthrown fault block.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.33-40
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• 1994

Effects of blanching on protein composition and texture in geoduck muscle during frozen storage at $-20^{\circ}C$ were investigated. In frozen muscle, sarcoplasmic protein and myofibrillar protein were decreased, while alkali-soluble protein increased rapidly. During the storage of the blanched muscle(at $95^{\circ}C$ for 2 min.), sarcoplasmic and myofibrilla protein showed slow decreases. The muscle blanched for 2 min(BM) showed the best texture among the samples treated with various blanching times(at $95^{\circ}C$ for 1, 2, 3, and mins). In comparing the textures of BM with raw muscle, hardness of BM was similar raw muscle, and elasticity and stress relaxation of BM revealed lower levels than those of raw muscle, but break elongation and toughness were higher. In the changes of texture of raw muscle and BM during the frozen storage, as the storage time lengthened, hardness and toughness of both muscles were stronger, and both stress relaxations showed greatly decreases during initial storage(7 days), and break elongation level of raw muscle showed rapid increases in 100 days but there were no changes in that of BM, Elasticity of raw muscle gradually reduced during storage while that of BM increased.