• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.97-100
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• 2007

Fuel Cell Stack performance, which is influenced by the maintenance of a constant internal environment, requires high levels of air tightness. Used for analysis, gasket for fuel cell is made of elastic rubber materials and placed over separator, and shape of deformation of a gasket affects the transformation separator and airtightness while fastening structure. Separator as made of steel sheet isn't broken under pressure but can affect gas and cool water flow by the plastic deformation process. Therefore， it is understood that assembly process is well developed in case distribution of stress and shape of deformation is shown uniformly. This study is conducted on the assumption that a fuel cell maintenance is advantageous in that conditions. In this paper, analyses of unit cell and partial model were performed and distribution of stress and shape of deformation of Gasket and separator were analyzed to evaluate the airtightness while fastening structure.

• The Journal of the Acoustical Society of Korea
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• 제29권1E호
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• pp.28-37
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• 2010

This article reviews recent developments in the emerging field of cellular-level biomedical ultrasonics with the specific focus on the mechanics of ultrasound-cell interaction. Due to the nature of the field at its relative infancy, the review poses more questions than it provides answers. Discussed are topics such as the basic structure of a biological cell, the origin of cell's elasticity, a theoretical framework for ultrasound-cell interaction, and shape deformation of cells and its measurement, Some interesting problems for future study are proposed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.207-210
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• 2004

The deformation behavior of copper during equal channel angular pressing (ECAP) was calculated using a three-dimensional version of a constitutive model based on the dislocation density evolution. Finite element simulations of the variation of the dislocation density and the dislocation cell size with the number of ECAP passes are reported. The calculated stress, strain and cell size are compared with the experimental data for Cu deformed by ECAP in a modified Route C regime. The results of FEM analysis were found to be in good agreement with the experiments. After a rapid initial decrease down to about 200 nm in the first ECAP pass, the average cell size was found to change little with further passes. Similarly, the strength increased steeply after the first pass, but tended to saturate with further pressings. The FEM simulations also showed strain non-uniformities and the dependence of the resulting strength on the location within the workpiece.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1663-1666
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• 2007

The finite element method is applied to analyze the deformation mechanisms in the closed-cell Al foam under the compression. The modeling of the real cellular structure proceeds with the concept of the reverse engineering. First of all, the small, $10{\times}\;10{\times}\;10mm^3$ sized specimens of the closed-cell Al foam are prepared. The micro focus X-ray CTsystem of SHIMADZU Corp. is used to scan the full structures of the specimens. The scanned structures are converted to the geometric surfaces and solids through the software for 3-D scan data processing, RapidFormTMof INUS Tech. Inc. Then the solid meshes are directly generated on the converted geometric solids for the finite element analysis. The large elastic-plastic deformation and 3-D contact problems for the Al cellular material are considered. The clear and successful analysis for the deformation mechanisms in the closed-cell Al foam is carried out through the comparison of the numerical results in this research with the referred experimental ones.

• 소성∙가공
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• 제15권6호
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• pp.441-444
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• 2006

The deformation behavior of copper during equal channel angular pressing(ECAP) was calculated using a three-dimensional version of a constitutive model based on the dislocation density evolution. Finite element simulations of the variation of the dislocation density and the dislocation cell size with the number of ECAP passes are reported. The calculated stress, strain and cell size are compared with the experimental data for Cu deformed by ECAP in a modified Route C regime. The results of FEM analysis were found to be in good agreement with the experiments. After a rapid initial decrease down to about 200nm in the first ECAP pass, the average cell size was found to change little with further passes. Similarly, the strength increased steeply after the first pass, but tended to saturate with further pressings. The FEM simulations also showed strain non-uniformities and the dependence of the resulting strength on the location within the workpiece.

• 한국전기전자재료학회논문지
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• 제15권10호
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• pp.902-908
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• 2002

Homogeneously aligned nematic liquid crystal displays (LCDs) driven by in-plane or fringe field were known to exhibit wide viewing angle and appeared to be black in the off state. However, the existence of spacers inside the cell causes the deformation of the liquid crystal molecules. Such a deformation of the liquid crystal causes light-leakage in the dark state, which lowers contrast ratio of the display. We found that the light-leakage due to deformation of the LC director near the spacer mainly depends on the dielectric anisotropy and the ratio of elastic constants of the LC. In this paper, the mechanism on deformation of the LC near spacer is investigated by optical polarizing microscopy.

• 한국산학기술학회논문지
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• 제15권7호
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• pp.4065-4071
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• 2014

PV셀과 리본의 솔더링 공정에서 열풍온도에 따른 $200{\mu}m$ 두께의 PV셀의 온도분포와 변형량의 해석 결과는 실험 측정치와 거의 일치함을 알 수 있었다. 또한 전기효율은 설정온도 $390^{\circ}C$로 PV셀을 솔더링한 모듈에서 가장 좋은 결과가 나타났다. 열풍온도를 $350^{\circ}C$로 설정하고 $150{\mu}m$ 두께의 PV셀을 솔더링 해석한 결과, 최대 변형량이 약 5.9mm로서 상당히 큰 값임을 확인할 수 있었으며, 열풍온도를 보다 낮은 온도로 설정해야 변형량이 감소하고 전기효율이 향상될 것을 예측하였다.

• 대한기계학회논문집A
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• 제28권7호
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• pp.877-884
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• 2004

In this paper, structural analysis is performed to investigate the deformation of porous media in a proton exchange membrane fuel cell (PEMFC). Structural deformation of air plate of the fuel cell causes the change in configuration and cross sectional area of the channel. The distributions of mass flow rate and pressure are major factors to decide the performance of a PEMFC. These factors are affected by channel configuration of air plate. Two kinds of numerical air plate models are suggested for flow analyses. Deformed porous media and undeformed porous media are considered for the two models. The Numerical flow analysis results between deformed porous media and undeformed porous media have some discrepancy in pressure distribution. The pressure and velocity distribution under a working condition are numerically calculated to predict the performance of the air plates. Pressure and velocity distributions are compared for two models. It is shown that structural deformation makes difference in flow analysis results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.72-72
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• 2010

The PV module company use variable process step and type. Especially soldering process is important, because crystalline cell can be bow by beating temperature. Most PV module company use hot air soldering type in the tabbing & string process. Although hot air type is used widely but this type is bound to influence on cell damage. So recently new way is introducing like a high current way. In this paper, we compare with characteristics of each soldering type and then conform a method to minimize solar cell deformation. Actually solar cell deformation show many difference by fix position and cooling time after soldering step.

• Advances in nano research
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• 제13권3호
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• pp.297-312
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• 2022

Coughing and breath shortness are common symptoms of nano (small) cell lung cancer. Smoking is main factor in causing such cancers. The cancer cells form on the soft tissues of lung. Deformation behavior and wave vibration of lung affected when cancer cells exist. Therefore, in the current work, phase velocity behavior of the small cell lung cancer as a main part of the body via an exact size-dependent theory is presented. Regarding this problem, displacement fields of small cell lung cancer are obtained using first-order shear deformation theory with five parameters. Besides, the size-dependent small cell lung cancer is modeled via nonlocal stress/strain gradient theory (NSGT). An analytical method is applied for solving the governing equations of the small cell lung cancer structure. The novelty of the current study is the consideration of the five-parameter of displacement for curved panel, and porosity as well as NSGT are employed and solved using the analytical method. For more verification, the outcomes of this reports are compared with the predictions of deep neural network (DNN) with adaptive optimization method. A thorough parametric investigation is conducted on the effect of NSGT parameters, porosity and geometry on the phase velocity behavior of the small cell lung cancer structure.