• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.306-313
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• 2015

In this study, the change of optical characteristics was studied according to the micro optical pattern provided by photo lithography followed by thermal reflow process. The shape and luminance variation with micro pattern was evaluated by SEM and spectrometers. Also, we analyzed the luminance characteristics using the 3D-optical simulation (Optis works) program. As a result, we found that the radius of curvature(R) in micro pattern is decreased up to 77%($150^{\circ}C$) compared to the radius of curvature at the condition $100^{\circ}C$, which is caused by efficient reflow of organic material without chemical changes. The highest enhancement of brightness with optimum micro pattern was obtained at the condition of $120^{\circ}C$ reflow process. The brightness gain with optical micro patterns is more than 15% at the condition of R=16.95 um, ${\Theta}=77.14^{\circ}$ compared to original optical source. The results of light simulation with various radius of curvature and side angle of pattern shows the similar result of experiment evaluation of light behavior on optical micro patterns. It is regarded that the more effect on light enhancement was contributed by side angle which is effective factor on light reflection, rather than the curvature of micro-patterns.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.112-119
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• 2000

A die-casting junction method is usually used to manufacture the tub of an IH(induction heating) jar. If there is a very small air bubble in the junction area, the thermal conductivity is deteriorated and local overheat occurs. Such problem brings serious inferiority of the IH jar. In this paper, we propose a new method to detect such defect with simply measured thermal data. Thermal distribution of preheated tubs is obtained by scanning with infrared thermal sensors and analyzed with the statistic pattern recognition method. By defining the characteristic feature as the temperature difference between sensors and using ellipsoid function as decision boundary, a supervised learning method of genetic algorithm is proposed to obtain the required parpameters. After applying the proposed method to experiment, we have proved that the rate of recognition is high even for a small number of data set.

• Advances in nano research
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• v.10 no.5
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• pp.423-435
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• 2021

This paper examines the thermal post-buckling behaviors of graphene-reinforced metal matrix composite (GRMMC) laminated cylindrical panels which possess in-plane negative Poisson's ratio (NPR) and rest on an elastic foundation. A panel consists of GRMMC layers of piece-wise varying graphene volume fractions to obtain functionally graded (FG) patterns. Based on the MD simulation results, the GRMMCs exhibit in-plane NPR as well as temperature-dependent material properties. The governing equations for the thermal post-buckling of panels are based on the Reddy's third order shear deformation shell theory. The von Karman nonlinear strain-displacement relationship and the elastic foundation are also included. The nonlinear partial differential equations for GRMMC laminated cylindrical panels are solved by means of a singular perturbation technique in associate with a two-step perturbation approach and in the solution process the boundary layer effect is considered. The results of numerical investigations reveal that the thermal post-buckling strength for (0/90)_5T GRMMC laminated cylindrical panels can be enhanced with an FG-X pattern. The thermal post-buckling load-deflection curve of 6-layer (0/90/0)_S and (0/90)_3T panels of FG-X pattern are higher than those of 10-layer (0/90/0/90/0)_S and (0/90)_5T panels of FG-X pattern.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.307-314
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• 2009

Large area micro pattern replication has promising application potential in many areas. Rolling imprint process has been demonstrated as one of the most competitive processes for such micro pattern replication, because it has advantages in low cost, high throughput and high efficiency. In this paper, we developed a prototype of roll-to-flat(R2F) thermal imprint system for large area micro pattern replication process, which is one of the key processes in the fabrication of flexible displays. Experimental tests were conducted to evaluate the feasibility of system and the parameters' effect on the process, such as flat mold temperature, loading pressure and rolling speed. 100mm $\times$ 100mm stainless steel flat mold and commercially available polycarbonate sheets were used for the tests. The experimental results showed that the developed R2F system is suitable for fabrication of various micro devices with micro pattern over large area.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.3
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• pp.431-436
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• 2014

In this paper, temperature change properties on the 210kW-class Interior Permanent Magnet Synchronous Motor (IPMSM) are performed with the cooling performance of a water cooling device through the thermal characteristic analysis of the IPMSM considering a real driving pattern of urban railway vehicles. First, the thermal analysis modeling of 210kW-class IPMSM, which is an alternative to the conventional induction motor, and its water cooling device is conducted. Next, the thermal characteristic analysis of the IPMSM considering a real driving pattern of urban railway vehicles is performed using 2-Dimensional FEM tool. Finally, the calculated characteristic results are analyzed. Consequently, it is confirmed that the internal temperature of the 210kW-class IPMSM may be lowered to about 42~52% by maintaining the coolant flow rate of the water cooling device (Cross sectional shape of the pipe has 220mm width and 10mm height) for 0.2kg/s level.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.894-903
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• 2011

In this paper, the capability index is introduced in order to improve the reliability of new concept machine tools and the method to improve the machine accuracy from the analysis of cutting process, statistical methodology and influence factors are proposed. In addition, the rib structure of bed and column in machine tools is analyzed by using the thermal impact method in order to analogize the rib pattern which has the small thermal deformation under thermal boundary condition. In the analysis of column rib structure, thermal boundary condition is separated to heat conduction and heat transfer to appropriate real boundary condition. Finally, performance chart of bed and column rib structure is provided for designer to estimate each rib pattern and select rib structure appropriating to thermal condition.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.2
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• pp.202-211
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• 2006

Objectives : This study is designed to evaluate correlation between the data of D.I.T,I examination in Bell's palsy and the improving period. Methods : This study researched into the clinical statistics for 50 patients who are in Bell's palsy and they are treated with oriental medical care of Dongshin university during 18months from January 1, 2005 to June 1, 2006. The data which examinated by D.I.T.I, are the thermal difference of normal and abnormal site of acupuncture int Gl4 BL2 GB3 S3 S4 S6 TE17 in Bell's palsy. Result : There was statistic significance between thermal difference of normal, abnormal site and the improving period. The period was shorter in normal thermal pattern than hypothermal pattern, hyperthermal pattern. Conclusion : According to the result, there was a statistic significance that more thermal difference and more difficult to recover in Bell's palsy.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.12
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• pp.1419-1424
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• 2011

Nanoimprint lithography is a next generation lithography technology, which enables to fabricate nano to micron-scale patterns through simple and low cost process. Nanoimprint lithography has been applied in various industry fields such as light emitting diodes, solar cells and display. Functional patterns, including anti-reflection moth-eye pattern, photonic crystal pattern, fabricated by nanoimprint lithography are used to improve overall efficiency of devices in that fields. For these reasons, in this study, sub-micron-scaled functional patterns were directly fabricated on Si and glass substrates by thermal imprinting process using ZnO nano-particles dispersion resin. Through the thermal imprinting process, arrays of sub-micron-scaled pillar and hole patterns were successfully fabricated on the Si and glass substrates. And then, the topography, components and optical property of the imprinted ZnO nano-particles/resin patterns are characterized by Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy and UV-vis spectrometer, respectively.

• Journal of Information Display
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• v.10 no.4
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• pp.202-205
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• 2009

An automated circuit repair system was developed for enhancing the yield of nondefective liquid crystal panels, focusing on the resist patterns on the circuit material layer of thin-film transistor (TFT) substrates prior to etching. The developed system has an advantage over the parallel conventional system: In the former, the repair conditions depend on the type of resist whereas in the latter, the repair parameters must be fine-tuned for each circuit material. The developed system consists of a resist pattern defect inspection system and a pattern repair system for short and open defects. The repair system performs fine corrections of abnormal areas of the resist pattern. The open-repair system is equipped with a syringe to dispense resist. To maintain a stable resist diameter, a thermal insulator was installed in the syringe system. As a result, the diameter of the dispensed resist became much more stable than when no thermal insulator was used. The resist diameter was kept within the target of $400{\pm}100{\mu}m$. Furthermore, a prototype system was constructed, and using a dummy pattern, it was confirmed that the system worked automatically and correctly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.3
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• pp.223-226
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• 2004

Injection molding using plastic materials was expected to mass production of structure with nano pattern for low cost phase. The PDMS mold was produced easily and uniformly by using thermal embossing. Quartz master for embossing method was made using electron beam lithography it had 100-500 nm size of line and dot type. The PDMS mold was produced after a brief hardening process and the master removal. The results show that various patterns are successfully fabricated the nano scale.. The replicated mold would be useful a stamper fabrication for injection molding.