• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1042-1047
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• 2004

Urethane is a high polymeric and elastic material useful in designing mechanic parts that cannot be molded in rubber or plastic material. Especially, urethane is high in mechanical strength and anti-abrasive. Hereby, an urethane coated aluminum wheel is used for supporting of OHT vehicle moving back and forth to transport products. For the sake of verifying the safety of the vehicle, structural safety for applied maximum dynamic load on a urethane wheel needs to be carefully examined while driving. Therefore, we have performed the dynamic simulation on the OHT vehicle model. Although the area definition of applied load can be obtained from the previous study of Hertzian and Non-Hertzian contact force model when having exact properties of contact material, static analysis is simulated, since the proper material properties of urethane have not been guaranteed, after we have performed the actual contact area test for each load. In case of this study, the method of distributing load for each node is included. Finally, in comparison with result of analysis and load-displacement curve obtained from the compression test, we have defined the material properties of urethane. In the analysis, we have verified the safety of the wheel. After all, we have performed a mode analysis using the obtained material properties. With the result, we have the reliable finite element model.

• 펄프종이기술
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• 제46권3호
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• pp.11-19
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• 2014

Reliability of the novel automatic system capable of measuring both St$\ddot{o}$ckigt sizing degree and contact angle at a time was evaluated through the calculation of its repeatability and reproducibility based on TAPPI Standard Method T 1200. As the basis weight of paper specimen increased, the repeatability and reproducibility of the automatic system became more improved than those from Hercules sizing test and contact angle test designated on TAPPI Standard Method T 530 and T 558. The more improved repeatability and reproducibility implies that a single tester can obtain the similar results under similar test conditions in spite of repetitive testing using the automatic system, and likewise that multiple testers can respectively reproduce similar data without big variation from the same paper specimen using the automatic system. In conclusion, this study is greatly meaningful in having developed the world's first automatic system to measure both St$\ddot{o}$ckigt sizing degree and contact angle simultaneously with excellent repeatability and reproducibility.

• 한국정밀공학회지
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• 제22권10호
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• pp.114-120
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• 2005

Urethane is a high polymeric and elastic material useful in designing mechanic parts that cannot be molded with rubber or plastic material. In particular, urethane is high in mechanical strength and anti-abrasive. Hereby, a urethane coated aluminum wheel is used to support of the OHT vehicle moving back and forth to transport products. For the sake of verifying the safety of the vehicle, structural safety fur applied maximum dynamic load on a urethane wheel must be examined carefully while driving. Therefore, we performed a dynamic simulation on the OHT vehicle model and we determined the driving load. The area definition of applied load may be obtained from the previous study of Hertzian and Non-Hertzian contact force model having exact properties of contact material. But the static analysis is simulated after we have performed the actual contact area test for each load since the proper material properties of urethane have not been guaranteed. In this study, the method of distributing loads for each node is included. Finally, in coMParison with the results of analysis and load-displacement curve obtained from the compression test, we have defined the material properties of urethane. In the analysis, we verified the safety of the wheel. Finally, we performed a mode analysis using the obtained material properties. With these results, we presented a reliable finite element model.

• Tribology and Lubricants
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• 제34권3호
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• pp.115-122
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• 2018

Chemical mechanical polishing (CMP) is a hybrid processing method in which the surface of a wafer is planarized by chemical and mechanical material removal. Since mechanical material removal in CMP is caused by the rolling or sliding of abrasive particles, interfacial friction during processing greatly influences the CMP results. In this paper, the trend of tribology research on CMP process is discussed. First, various friction force monitoring methods are introduced, and three elements in the CMP tribo-system are defined based on the material removal mechanism of the CMP process. Tribological studies on the CMP process include studies of interfacial friction due to changes in consumables such as slurry and polishing pad, modeling of material removal rate using contact mechanics, and stick-slip friction and scratches. The real area of contact (RCA) between the polishing pad and wafer also has a significant influence on the polishing result in the CMP process, and many researchers have studied RCA control and prediction. Despite the fact that the CMP process is a hybrid process using chemical reactions and mechanical material removal, tribological studies to date have yet to clarify the effects of chemical reactions on interfacial friction. In addition, it is necessary to clarify the relationship between the interface friction phenomenon and physical surface defects in CMP, and the cause of their occurrence.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.561-565
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• 2007

Because of a good wear resistance and a stable contact resistance, Ag-CdO is widely used as electrical contact material. But, the Cd-oxide mainly exists as a coarse particle and adversely affected to environment. As a reason, $Ag-SnO_2$ alloy has been developed. The Sn-oxide maintains stable and fine particle even at high temperature. In order to investigate the effect of Misch metal (Mm) additional that affects the formation of the oxide and the formation of fine matrix Ag, we studied the microstructures and properties of Ag-Sn-In(-Mm) material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. The Mm addition makes Ag matrix more fine than no Mm addition. The reason is that the addition of Misch metal decreased a latent heat of fusion of alloy, as a result the rapid solidification effect of alloy is increased. The maximum hardness shows at 0.3 wt%Mm. after that the hardness is decreased until 0.4 wt% Mm, but still larger than no Mm addition alloy. At 0.5 wt% Mm alloy, the precipitation of Misch metal causes a decrease of hardness than no Mm addition alloy.

• 한국전기전자재료학회논문지
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• 제24권12호
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• pp.988-991
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• 2011

We fabricated a copper phthalocyanine (CuPc) based field-effect transistor with different device structure as a bottom and top contact FET. Also, we used a $SiO_2$ as a gate insulator and analyzed using a current-voltage (I-V) characteristics of the bottom and top contact CuPc FET device. In order to discuss the channel formation, we were observed the capacitance-gate voltage(C-V) characteristics of the bottom and top contact CuPc FET device.

• 한국전기전자재료학회논문지
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• 제24권12호
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• pp.1010-1017
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• 2011

The use of plated front contact for metallization of silicon solar cell may alternative technologies as a screen printed and silver paste contact. This technologies should allow the formation of contact with low contact resistivity a high line conductivity and also reduction of shading losses. A selective emitter structure with highly dopes regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing. When fabricated Ni/Cu plating metallization cell with a selective emitter structure, it has been shown that efficiencies of up to 18% have been achieved using this technology.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.5-6
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• 2009

In this paper, plasma ion implant is performed with $PH_3$ gas diluted by helium gas on P-type Si wafer (100). Spike Rapid Thermal Processing(RTP) annealing performed for 30~60 sec from $800\;^{\circ}C$ to $1000\;^{\circ}C$ in $N_2+O_2$ ambient. Crystalline defect is analyzed by Transmission Electron Microscope(TEM) and Double crystal X-ray Diffraction(DXRD). Contact resistivity($\rho c$), contact resistance(Rc) and sheet resistance(Rs) are analyzed by measuring Transfer Length Method(TLM) using 4155C analysis. As annealing temperature increase, Rs decrease and ${\rho}c$ and Rc increase at temperature higher than $850\;^{\circ}C$. We achieve low Rs, ${\rho}c$ and Rc with Plasma ion implant and spike RTP.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.145-149
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• 1995

The metallization is the key to determining cell costs, call performance, and cell and system reliabiltiy. The Burled Contact Solar Cell (BCSC) was specifical1y desinged to be compatible tilth low cost, mass production techniques and avoid the conventional metallization problem. By using electroless plating trchniqeu, we performed this metallization inexpensively and reliabley, This paper presents the details of the optimization procedure of metallization schemes on laser grooved cell surface Commercially available Ni ,Cu, and Ag plating solutions were applied for the cell metallization. The application of those solutions on the buried contact front metalization has resulted in an cell efficiency of 18.5% The cell parameters are an open circuit voltage of 651 mV, short circuit current density of 38.6 mA/$\textrm{cm}^2$, and fill factor of 73.5%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.151-154
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• 1998

We have investigated a correlation of the electrical properties of the Pd/Ge/Pd/Ti/Au ohmic contact on n-InGaAs with its microstructures for the high temperature application of compound semiconductor devices. The samples were heat-treated by the rapid thermal annealing at various temperatures. In the contact system, moderately good specific contact resistance was obtained even before annealing because of the low metals-InGaAs barrier height, and better ohmic performances were observed by annealing up to 400˚C. But the ohmic performance was degraded after annealing at 450˚C due to the increment of Pd$_2$Ga$\sub$5/ phases.