• BMB Reports
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• 제37권4호
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• pp.460-465
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• 2004

A 16-residue polypeptide model with the sequence acetyl-YALSLAATLLKEAASL-OH was derived by rational de novo peptide design. The designed sequence consists of amino acid residues with high propensity to adopt an alpha helical conformation, and sequential order was arranged to produce an amphipathic surface. The designed sequence was chemically synthesized using a solid-phase method and the polypeptide was purified by reverse-phase liquid chromatography. Molecular mass analysis by electro-spray ionization mass spectroscopy confirmed the correct designed sequence. Structural characterization by circular dichroism spectroscopy demonstrated that the peptide adopts the expected alpha helical conformation in 50% acetonitrile solution. Liposome binding assay using Small Unilamellar Vesicle (SUV) showed a marked release of entrapped glucose by interaction between the lipid membrane and the tested peptide. The channel-forming activity of the peptide was revealed by a planar lipid bilayer experiment. An analysis of the conducting current at various applied potentials suggested that the peptide forms a cationic ion channel with an intrinsic conductance of 188 pS. These results demonstrate that a simple rational de novo design can be successfully employed to create short peptides with desired structures and functions.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 압출 및 인발 심포지엄
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• pp.20-23
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• 1999

The current three-stage cold extrusion process including upsetting to produce a flange is investigated for the purpose of improvement of manufacturing process. The main goal of this study is to obtain an appropriate process sequence which can produce the required part most economically without overloading of tools and select an appropriate process for reducing manufacturing cost. The current process sequence is simulated and design criteria are examined. Based on the results of simulation of the current three-stage process, a design strategy for improving the process sequence is developed using the thick-wall pipes. Based on the results of simulation of the one-stage processes, the forming processes of a flange for improving the conventional process are proposed.

• 소성∙가공
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• 제6권4호
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• pp.291-299
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• 1997

This paper is concerned with the design of process sequence to form the inner skin of landing gear. The inner skin of landing gear is a part of airplane which is known to be difficult to form its shape. Our study investigates the production method of inner skin and examines the design criteria by three dimensional elastic-plastic finite element method. Based on the results of simulation, design strategy for improving the process sequence is developed using stretch forming process. The final product of inner skin is produced in multi-stage operations with annealing treatment to meet the required capacity of press. The numerical results show that the newly designed process can produce the required part successfully within the design criteria.

• 대한기계학회논문집
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• 제13권1호
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• pp.190-198
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• 1989

본 연구는 PC(personal computer)를 이용한 냉간단조 프레스용 축대칭 1,2단 원형 컵 제품의 공정설계 및 금형설계를 위한 대화식 프로그램인 "CUP- FORMING"과 "CUP-DIE"의 개발에 대하여 설명한다.quot;의 개발에 대하여 설명한다.

• 한국정밀공학회지
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• 제14권5호
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• pp.76-84
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• 1997

A process sequence in precision press forming of electrnic components is investigated by the finite element method. Aperture, a key component of electronic gun, is formed through a sequence of about 15 operation, among which the beading & bending, the first piercing, the first coining, and the second coining operations are expected to be most critical in view of industrial experts opinions. Thus, the analysis per- formed by a commercial code MARC focuses on the three operations, and comparisons are made between the results of the analysis and the measurements of experimental forming of the component.

• 대한기계학회논문집A
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• 제20권11호
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• pp.3387-3397
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• 1996

The Hub is an auto mobile component used as aircon clutch. The important aspects in cold forging of the Hub with complex geometry are the design of an initial shape of the workpiece, the possibility of the forming by one-stage operation and the determination of number of performs, etc. Based on the systematic procedure of process sequence design, in this paper, the forming operation of cold forged part of the Hub is designed by the rigid-plastic finite element method. The two design criterion of geometrical filling without defect and an even distribution of effective strain in final product are investigated in controlling the initial shape of the workpiece and preform configuration. It is noted that one preforming operation is required in order to obtain final product of the Hub.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.3-8
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• 2006

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module optimal design technique and horizontal split of die insert were investigated for determining appropriate dimensions of components of multi-former die set. Results obtained, using the modules, enable the design and manufacture of a die set for a multi-former to be more efficiently performed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1307-1311
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• 2004

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. They can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module an optimal design technique and horizontal split die were investigated for determining appropriate dimensions of components of multi-former die set. It is constructed that the proposed method can be beneficial for improving the tool life of die set at practice.

• 한국정밀공학회지
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• 제17권6호
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• pp.127-134
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• 2000

The current three-stage cold farming process to produce a flange is investigated for the purpose of improvement of manufacturing process. The main goal of this study is to obtain an appropriate process sequence, which can produce the required part with less manufacturing cost. The current process sequence is simulated using finite element method and design criteria are examined. Based on the results of simulation of the current three-stage process. a design strategy for improving the process sequence is analyzed using the thick-walled pipes. Because it has a reduced process-sequence without buckling of the workpiece or overloading of tools, the new process has distinct advantages over the conventional process. Numerical results show that the newly proposed process with selected presses is the most economical way to produce the required part.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.80-85
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• 2002

The progressive die for U-bending production part is a very specific division. This study reveals the Sheet metal forming process with multi-forming die by Center Carrier type feeding system. Through the FEM simulation by DEFORM it was accepted to u-bending process as the first performance to design in strip process layout design. The next process of die development was studied according to sequence of die development.