• 한국정밀공학회지
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• 제17권4호
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• pp.38-47
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• 2000

Recently, finite element method has been used as an effective tool in the design process of sheet metal forming. In the present study, an implicit method and an explicit method have been developed for 2D analysis and 3D analysis, respectively, and applied to several processes including plane strain draw bending and TWB sqaure cup drawing. Also, commercial codes are used for geometrically complex problems, such as tube hydroforming, "L" cup deep drawing and side frame forming. In this paper, basic formulations used in the methods are introduced and results obtained from the applications are discussed.discussed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.159-162
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• 2000

Wrinkles and shape distortions are generated during the forming of B-pillar(or center pillar) which is a component of the automobile side-frame. The stretch flanging modes at the joining part of the B-pillar and the roof-rail or the side-still give rise to forming problems when taior-welded blanks are applied to the side-frames. The authors simplified B-pillar lower part to T shaped section to investigate the forming behaviors. Three of die step locations and two of blank types were tested to show the effects of weld line locations and edge conditions on he forming of tailor welded blanks. The heights of body wrinkles and the strain distribution in the stretch flanged area were measured and compared.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.57-61
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• 1999

Springback after forming is the critical factor affecting the product quality. It is very difficult to predict the amount of springback not only because of complex geometry and material characteristics of the stamping product but because the methodology has not been established. In this study springback mechanism is introduced and experimental tryout and computer simulation are carried out for die design of automotive rear side frame. Futher springback was verified by comparing the result of computer simulation with the measured tryout result.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1105-1106
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• 2010

• 한국자동차공학회논문집
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• 제18권5호
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• pp.45-49
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• 2010

The automotive industry has shown a growing interest in tube hydroforming during the past years. The advantages of hydroforming (less thinning, a more efficient manufacturing process, etc.) can, for instance, be combined with the high strength of extra high strength steels, which are usually less formable, to produce structural automotive components which exhibit lower weight and improved service performance. Design and production of tubular components require knowledge about tube material and forming behavior during hydroforming and how the hydroforming operation itself should be controlled. These issues are studied analytically in the present paper. In this study, the whole process of rear sub-frame parts development by tube hydroforming using AA6061 material is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Engineering) to confirm hydroformability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive rear sub-frame by hydroforming process were carefully investigated. Overall possibility of hydroformable rear sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending and hydroforming. In addition, all the components of prototyping tool are designed and interference with press is examined from the point of geometry and thinning.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 제5회 박판성형 SYMPOSIUM
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• pp.93-98
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• 2006

Warm forming technology was classified into hot gas forming of using compressible fluid as a nitrogen gas and warm hydroforming of using the incompressible fluid as a thermal oil by using medium fluid. In this study, the aluminum side-rail part was developed with warm hydroforming technology. For the warm hydroforming system, top and bottom die was designed to insert heating cartridge in die cavity and special indirect fluid heating system was designed to heat the thermal oil. As increase the temperature, hydroformability was increased linearly. Aluminum side-rail center part was formed 90% at the internal pressure of 100bar and perfectly formed at 300bar within a moderate temperature. The tube material used for warm hydroforming was a aluminum 6000 series alloy with the diameter of 120mm, thickness of 5mm, length of 1,300mm. Warm hydroformed side-rail center part had 20% of maximum expansion ratio and below 20% of maximum thinning ratio at corner radius. This results were provided to show warm hydroforming possibility for aluminum automotive components.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.132-137
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• 2004

In order to reduce automobile parts weight, TWB(Tailored welded blank) forming is widely used in the forming of car panel, such as door inner, side outer panels. In this study, one of the current problems of TWB forming was analyzed, especially for the try-out process of TWB door inner panel without frame. A comparison was made between actual panel measurements and results of forming analysis for formability and springback.

• 한국공간구조학회논문집
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• 제19권2호
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• pp.35-42
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• 2019

The purpose of this paper is to evaluate the structural performance of joints between modules with steel plate press forming type non-symmetric cross section. The main experimental variables are direction of load, whether vertical bolts are fastened, and whether the concrete inside the column is filled. A total of three experiments were performed for each variable. Experimental results show that the behavior of the joints dominated by the local buckling deformation of the upper and lower beam flanges of the module joints, and the final failure was the fracture of the column-beam welds. In case of short side direction, it is possible to secure the performance of intermediate moment frame (0.02 rad). In case of long side direction, it is evaluated that the performance of special moment frame (0.04 rad) is secured regardless of whether or not concrete is infilled in the column.

• 대한한방내과학회지
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• 제30권3호
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• pp.465-480
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• 2009

Objective : Lonicerae Flos has detoxifying properties and been used as antipyretic, antibacterial and antitumor. Fermentation of herbal medicine is known to increase the absorption, enhance effectiveness, decrease herbal toxicity and reduce side-effects. This study was performed to measure the effects of fermented Lonicerae Flos on influenza A/WSN (H1N1) virus replication. Material and Methods : Lonicerae Flos was fermented by Lactobacillus casei PM1. Fermented Lonicerae Flos was treated for 12 hours to MDCK (Mardin Darby canine kidney) cells, then cell-virulence was observed by MTT assay for 12 hours, 24 hours, and 36 hours after treatment. Following cases were conducted for 0, 10, 100, and $1000{\mu}g/ml$ concentrations of fermented Lonicerae Flos under the same time-frame; the fermented Lonicerae Flos was treated to MDCK cells before and after contamination by A-type influenza virus. The fermented Lonicerae Flos and the virus were mixed directly. The influence was observed by MTT assay and plaque assay. Results : These findings suggest that the fermented Lonicerae Flos inhibited the virulence of influenza A virus in MDCK cells and suppressed the plaque forming colonies induced by influenza A virus. Furthermore, pretreatment with fermented Lonicerae Flos was more effective than post-treatment. The titer of influenza virus was reduced for all before and after influenza A virus inoculation.

• Journal of Microbiology and Biotechnology
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• 제10권2호
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• pp.161-168
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• 2000

Plasmid pLEX3 isolated from the recombinant cosmid library of Zoogloea ramigera 115 was found to be responsible for the restoration of the rugose colony phenotype. To confirm the essential region responsible for the complementation, subclones were constructed from plasmid pLEX3 and transformed into mutant strain Z. ramigera 115SLR. The recombinant plasmids pLEX10 and pLEX11 were shown to complement the slime-forming property of Z. ramigera 115SLR. In a compositional analysis of the exopolysaccharides from Z. ramigera 115, Z. ramigera 115SLR, and Z. ramigera 115SLR harboring plasmid pLEX11, the exopolysaccharides showed a similar composition with glucose, galactose, and side chain groups. The complete nucleotide sequence of the 3.25kb genocim DNA insert in plasmid pLEX11 was determined and its analysis identified two open reading frames which could encode two proteins. The gene products derived form the two open reading frames were confirmed by and in vivo transcription using a T7-RNA polymerase. The ORF1 produced a 30 kDa protein, whereas the ORF2 was found responsible for the complementation of the morphological mutation and produced a 14 kDa protein. An in vivo gene expression of plasmid pTEX10 showed another open reading frame encoding a 50 kDa protein. The gene products form ORF1 and ORF2 are regarded as novel proteins which do not show any homology with other proteins.