• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.144-152
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• 1998

Changes of biological components in haemolymph of Helicoverpa assulta Guenee were investigated during the development and pupae of cold-stress periods. Protein content was the highest in the larval stage, whereas it showed somewhat lower level at the cold-stressed pupae. The level of free amino acids was high in the larval and adult stages. Althougth decresed in pupal stage, the level of free amino acid remarkably increased at the cold-stressed pupae. Total lipids were a little increased at the pupal stage, after small quantity decreased in I-day old adults, and then remarkably decreased at the cold-stressed pupae. Glycogen was increased at the pupal stage, and somewhat decreased in the stage of adult, but remarkably decreased at the cold-stressed pupae. From thin layer chromatographic analysis, glucose was detected in small quantity at 1-day old pupae, one-day old adults, and cold-stressed pupae, respectively. Each .activity of acid and alkaline phosphatases was the highest in the 1 and 7-day old pupae, respectively, and both enzyme activities were increased about two-fold compared to the activity in the cold-stressed pupae. A total of 2 phosphatase isozymes were observed in throughout the developmental stage, and a new isozyme specific to cold-stressed pupae was identified.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.74-79
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• 2003

When workability at the a certain bulk deformation process is defined as the maximum plastic deformation capability that the workpiece can sustain without causing any cracks or fracture, the workability is dependent on the microstructure, initial workpiece shape, stress state developed during the deformation process, strain rata and presence of the interfacial friction between workpiece and tool. For a review purpose, the workability definition and test methods are summarized depending on the applied stress state at bulk deformation process in Table 1 at the text. In this study, the cold workabilities of as-cast A16061 bulk material have been measured and comparatively analyzed at the primary tensile stress state by using tensile specimens, the primary compressive stress state by using cylindrical specimens, and the forming limit diagram by ductile fracture.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.51-60
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• 2004

The stress analysis of cold-formed channel section steel beams under transverse load was conducted. The local buckling effect was included in the analysis using effective area concept. The proposed analytical model is capable of predicting accurate normal stress in the beam due to various behaviors including biaxial bending and warping. It was found to be appropriate for predicting stresses as well as deflection in the beam. A finite element model was developed to solve the analytical model.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.74-79
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• 2004

The shape of cold rolled steel sheets is the degree of flatness, and the flatter, the better. Because undesirable strip shapes of cold rolled steel sheets can affect not only visible problem but also automatic working process in customer's lines, the requirement of the customers is more and more stringent. So we usually used the tension leveler to make high quality of strip flatness. For the improvement of the quality of strip flatness, this report developed three-dimensional FEM (Finite Element Method) simulation model, and analysis about the strain and stress distribution of strip in the tension leveling process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.418-422
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• 2005

In this study, the die design and die series on the surface residual stress of cold drawn eutectoid steel wire has been investigated. Test pieces were fabricated using die series with different mean and final reduction ratio. Surface residual stresses in the axial direction were measured by X-ray diffraction, Broker's 2-dimensional GADDS system. Results were compared with stress profiles which were calculated by 3D and 2D finite element simulation, Hibbitt's ABAQUS 6.4 program in Finite Element Analysis. By means of FEA method, optimal die shape considering delta-parameter were induced and applied in order to determine die sequence designs. Balance of the drawing stresses was also introduced to optimize die sequence.

• Transactions of Materials Processing
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• v.15 no.2 s.83
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• pp.153-157
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• 2006

In this study, the die design and die series on the surface residual stress of cold drawn eutectoid steel wire have been investigated. Test pieces were fabricated using die series with different mean and final reduction ratios. Surface residual stresses in the axial direction were measured by X-ray diffraction, Bruker's 2-dimensional GADDS system. The results were compared with stress profiles that were calculated by 3D and 2D finite element simulations, ABAQUS 6.4 program in finite element analysis(FEA). By means of the FEA method, optimal die shape considering delta-parameter were induced and applied in order to determine die sequence designs. Balance of the drawing stresses was also introduced to optimize die sequence.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.165-171
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• 2003

In a structure, many components are fastened together using bolts, nuts and rivets through drilled holes. Not only do these fastened joints enable easy assembly and dismantling, they are also able to transfer as well as to distribute loads applied onto the structures. The major drawback of such connections, however, is that the fatigue life of the components is reduced by the presence of the hole since the stress concentration around the hole is increased. In addition, the hole drilling process itself may introduce defects or roughness at the surfaces of the hole that may cause further decrease in fatigue performance of the components. For applications where fatigue loadings are important, one way to compensate the decrease in fatigue life of the components is by introduction of beneficial compressive residual stress around the hole using cold working. The material used for this research were A12024-T351 and A17050-T7451 using the primary member of aircraft. We present, In this paper, the characteristics of coldworking by evaluation of the hole expansion ratio, residual stress distribution, and fatigue properties.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.13-13
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• 2022

Recently, stable crop production is threatened by the effects of climate change. In particular, it is difficult to consistently maintain agricultural policies due to large price fluctuations depending on the difference in total domestic rice production from year to year. For stable rice production amid changes in the crop growing environment, development of varieties with improved disease resistance and abiotic stress stability is becoming more important. In here, drought and cold tolerant trait have been studied. First, for the development of drought tolerant varieties, we analyzed which agricultural traits are mainly affected by domestic drought conditions. As a result, it was observed that drought caused by the lack of water during transplanting season inhibits the development of the number of tiller and reduces the yield. 'Samgang' was selected as a useful genetic resource with strong drought tolerant and stable tiller number development even under drought conditions by phenotype screening. Three of drought tolerant QTLs were identified using doubled haploid (DH) population derived from a cross between Nacdong and Samgang, a drought sensitive and a tolerant, respectively. Among these QTLs, when qVDT2 and qVDTl1 were integrated, it was investigated that the tiller number development was relatively stable in the rainfed paddy field conditions. It is known that the high-yielding Tongil-type cultivars are severely affected by cold stress throughout the entire growth stage. In this study, we established conditions that can test the cold tolerance phenotype with alternate temperature to treat low temperatures in indoor growth conditions similar to those in field conditions at seedling stage. Three cold tolerant QTLs were explored using population derived from a cross between Hanareum2 (cold sensitive variety, Tongil-type) and Unkwang (cold tolerant variety, Japonica). Among these QTLs, qSCT12 showed strong cold tolerant phenotype, and when all of three QTLs were integrated, it was investigated that cold tolerant score was relatively similar to its donor parent, Unkwang, in our experimental conditions. We are performing that development of new variety with improved cold tolerant through the introduction of these QTLs.

• Journal of Oral Medicine and Pain
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• v.23 no.4
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• pp.309-326
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• 1998

In general, the major causative factor of halitosis is thought to be a sulfated compounds. Clusterin, a sulfated glycoprotein-2(SGP-2), is frequently found in diabetic conditions and cold stress conditions. The same result is werum glucose level to diabeteic and cold stress conditions that founded Clusterin. Therefore, this study was performed to examine Clusterin in the slivary glands under stress conditions before insulin injection I.M. Fourty rats were diveded into 3 groups ; 1) 10 rats of gorup I were selected as a control 2) 15 rats beloning to group II were bathed in cold water for 30 seconds twice a day 3) 15 rats in group III received cold stress and injected I.M. with insulin. The rats were sacrifeced at day 0, 3, 5, 7 and 10 of the experiment and the submandibular glands and parotid galnds were removed. RNAs were purified from the salivary of the salivary glands were subjected to Hematoxillin-Eosin stainings and examined under the light microscope. The obtained results were as follows : 1. With immunohistochemistric method, in normal control goup, Clusterin was moderately stained in the intercalated ductal cell of the submandibualr glands, mild stained in the striated ductal cell of the submandibular glands, heavily stained on the cytoplasm of the intercalated ductal cell in the mucous submandibular glands nad slightrly stained in the intercalated ductal cell of the paroted gland, expressed negativity in the acina cell. 2. With immunohistochemistric method, Clusterin slightly increased in the acina cell of the submandibular glands under stress condition at 3 days after experement, moderately stained at 5 days after experiment so revealed positive response. And hearily in the intercalated ductal cell and mildly lin the acina celluar eytoplasm of the parotid glands under stress condition at 3 days experiment. 3. With immunohistochemistric method, no remarkable differences are found between the normal control group and stress conditioned group that insulin administration was performed before. 4. In the stressor-giving group, Clusterin mRNA was porminently expressed in submandibular gland after 5 days after experiment, in parotid gland after 3 days after experiment, performed in immunoelectrophoresis method. 5. In the insulin-injected nad stressor-giving group, Clusterin mRNA was not observed in all experimental submandibular and parotid gland, performed in immunoelectrophoresis method.

• Herbal Formula Science
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• v.10 no.2
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• pp.97-112
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• 2002

In order to investigate the effect of Sagoonja-Tang, Samool-Tang and Yookmijihwang-Tang against the cold, heat and immobilization stress, each formula was injected intragastically to mice exposed to forced cold water swimming($4^{\circ}C$), forced hot water swimming($42^{\circ}C$) and immobilization stress before measuring the change of plasma corticosterone level of mice. The results were as follows: 1. One hour after each Sagoonja-Tang, Samool-Tang, Yookmijihwang-Tang with the dose of 1g／kg, 3g／kg each were administered to mice, we put cold stress($4^{\circ}C$) on mice for 3min. Then those prescriptions didn't show any significant effect on plasma corticosterone level. however, Yookmijihwang-Tang(1g/kg) showed a significant increase(p〈0.05), and Samool-Tang(3g/kg) showed a small increase. 2. One hour after Samool-Tang, Sagoonja-Tang and Yookmijihwang-Tang with the dose of 1g／kg, 3g／kg each were administerd, mice exposed to heat stress($42^{\circ}C$) for 3 min. Samool-Tang(1g/kg) and Yookmijihwang-Tang(lg/kg) showed significant decrease of corticosterone level(p〈0.01, p〈0.05) but Sagoonja-Tang didn't change it. In the case of the dose of 3g/kg, only Samool-Tang decreased corticosterone level(P〈0.01), but Sagoonja-Tang, Yookmijihwang-Tang didn't make significant effect on plasma corticosterone level of the mice exposed to heat stress($42^{\circ}C$ ). 3. Those mice which exposed to immobilization stress one hour after Sagoonja-Tang, Samool-Tang, Yookmijihwang-Tang with the dose of 1g/kg and 3g/kg didn't show effective decrease of corticosterone level. However, Sagoonja-Tang(3g/kg), Samool-Tang(lg/kg, 3g/kg) showed the effect of mild increase of corticosterone level rather than decrease. These data revealed that the effect-variation of prescriptions depended on the kinds of stress and the dose of prescriptions had a different effect on therapy.