• Current Optics and Photonics
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• v.5 no.1
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• pp.72-76
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• 2021

The polarized micro-photoluminescence spectrum was analyzed to investigate the anisotropic localized states in a single GaAs quantum ring. An energy difference of ~0.1 meV was observed from the perpendicularly polarized spectrum measured by a pair of linear analyzers. Spectral dependence of the polarized emission was also characterized in terms of rotation and ellipticity angles using four Stokes parameters. While the rotation angle indicates the symmetric axis of an anisotropic quantum ring with a small variation (± 2°), the ellipticity angle varies from 7.4° down to -2.5°. We conclude that optical anisotropy and birefringence are induced by the crescent-like lateral shape of localized states.

• Current Optics and Photonics
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• v.6 no.1
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• pp.86-91
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• 2022

Two-photon fluorescence microscopy was performed on the enamel-dentin junction area of a human tooth using a femtosecond pulsed laser. We obtained a clear image contrast between the bright dentin and dark tubules with the autofluorescence generated from the endogenous fluorophores in dentin. The autofluorescence shows a broad spectrum due to complex cross links between dentinal collagens, which extend from blue to orange wavelengths (470-590 nm), but a gradual autofluorescence loss in photobleaching was observed for a long-term exposure under strong excitation. For increasing excitation power, we found that two-step decay becomes significant in the spectrally integrated autofluorescence.

• Journal of Engineering Education Research
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• v.8 no.2
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• pp.5-15
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• 2005

This paper describes the development of curriculum for the division of Mechatronics in Samcheok University to meet the requirement of Accreditation Board for Engineering Education of Korea(ABEEK). The curriculum of the department of mechatronics in South Korea and overseas university is analysed and then the curriculum is developed considering the synergistic combination of mechanical engineering, electronic engineering, control engineering and computer engineering. And then the geopolitical condition of university is reflected in the curriculum. ABEEK requirements for major of engineering are also reflected. As a result, interdisciplinary curriculum that provides analytic capability and pragmatic qualification to students is developed.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1289-1293
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• 2009

For the purpose of automatic management and enhancing quality of construction, information technology has been employed in construction field recently. As a consequence, informative construction, which utilizes information technology to reduce construction time and optimize construction sequence, becomes a state-of-art field of construction. Considering this case, construction field should more actively adopt other engineering technologies of rapidly advancing fields, such as electronic, control, and informative engineering, in order to reduce construction cost and to solve environmental problems as well as to enhance construction quality. In this aspect, this paper introduces a novel research field 'Geo-mechatronics', which stands for the convergence of geotechnical engineering and mechatronics (i.e. automation of mechanics using electronic technologies). Since the ground is ubiquitous in every infrastructure construction, the Geo-mechatronics research is crucial for the development of construction technology in the future. Moreover, it is believed to that the Geo-mechatronics research will make our construction industry to be more future-oriented and internationally comparative industry.

• Carbon letters
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• v.18
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• pp.67-70
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• 2016

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.597-598
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.513-514
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• 2006

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.4
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• pp.3-7
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• 2006

Confocal scanning microscopy is a measurement technique used to observe micrometer and sub-micrometer features due to its high resolution, nondestructive properties, and 3D surface profiling capabilities. The design, implementation, and performance test of a confocal scanning microscopy system are presented in this paper. A short-wavelength laser (405 nm) and an objective lens with a high numerical aperture (0.95) were used to achieve the desired high resolution, while the x- and y-axis scans were implemented using an acousto-optic deflector and galvanomirror, respectively. An objective lens with a piezo-actuator was used to scan the z-axis. A spatial resolution of less than 138 nm was achieved, along with successful 3D surface reconstructions.

• Journal of Industrial Technology
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• v.40 no.1
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• pp.19-23
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• 2020

In this paper, we proposed a PC-based CNC control system using EtherCAT-based servo drive and I/O device. The default communication of LinuxCNC is a parallel port, and data processing with high bandwidth is impossible. However, it is possible to apply various bandwidth devices through the application of EtherCAT, one of the industrial Ethernet communications with high bandwidth. Therefore, the hardware control method of LinuxCNC was applied through EtherCAT communication from the existing parallel port. Finally, through HAL configuration, I/O device operation check and 3-axis motion control proved the LinuxCNC system with EtherCAT.

• Journal of Engineering Education Research
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• v.11 no.3
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• pp.33-43
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• 2008

In this paper, mechatronics education in South Korea is analyzed and its improvement is proposed. For this purpose, discussion on the definition and evolution of mechatronics in South Korea, USA and EU is deployed first. It is revealed that most of the mechatronics education in USA and EU is remained in cross-disciplinary stage or curriculum stage, whereas that in South Korea is evolved to curriculum stage or organizational stage. The comparison of mechatronics curriculum between Korea and other countries and the problems of mechatronics education are included. The automation of machinery and factory plays one of major roles in mechatronics education in Korea, while mechatronics curriculum in USA and EU does not emphasize the automation. Mechatronics experiment in South Korea is organized to meet the National Qualification Test on mechatronics, and it is recommended to be more inventive. The way of improving the National Qualification Test of South Korea on mechatronics field is proposed. And, finally, efficient way of linking technical high school and university in mechatronics education is also proposed.