• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.130-130
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• 2012

Axial bindings of diatomic molecules to metalloporphyrins involve in the dynamic processes of biological functions such as respiration, neurotransmission, and photosynthesis. The binding reactions are also useful in sensor applications and in control of molecular spins in metalloporphyrins for spintronic applications. Here, we present the binding structures of diatomic molecules to surface- supported Co-porphyrins studied using scanning tunneling microscopy. Upon gasexposure, three-lobed structures of Co-porphyrins transformed to bright ring shapes on Au(111), whereas H2-porphyrins of dark rings remained intact. The bright rings are explained by the structures of reaction complexes where a diatomic ligand, tilted away from the axis normal to the porphyrin plane, is under precession. Our results are consistent with previous bulk experiments using X-ray diffraction and nuclear magnetic resonance spectroscopy.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.967-968
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• 2007

This report is the study for laser scanning. Scanning control of $CO_2$ laser, He-Ne laser, used for the treatment of body skin, has relatively low band about hundered Hz. It could be used as a substitiute for expensive galvanometer that is the established scan method, which operates the number of KHz movement by using step motor when it operates low speed. To increase the accuracy of step motor's the angle of rotation, We could materialize 100Hz low band by using open loop, closed loop method with microprocessor. This causes it to be stable even direction by attaching electric capacity sensor. Therefore, We could expect to reduce the cost by manufacturing low band scanner rather than costly feedback galvanometer.

• Current Optics and Photonics
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• v.5 no.6
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• pp.680-685
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• 2021

We propose a technique that reconstructs a hologram whose pixel number is greater than the pixel numbers of a conventional image sensor. The pixel numbers of the hologram recorded by optical scanning holography (OSH) increases as the scan area becomes larger. The reconstruction time also increases drastically as the size of the hologram increases. The holographic information of a three-dimensional (3D) scene is distributed throughout the recorded hologram; this makes the simple divide-and-stitch approach fail. We propose a technique that reconstructs the hologram without loss of holographic information. First, we record the hologram of a 3D scene using OSH. Second, we segment the hologram into sub-holograms that contain complete holographic information. Third, we reconstruct the sub-holograms simultaneously. Finally, we rearrange the reconstructions of the sub-holograms.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.8
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• pp.27-33
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• 2001

The performance of the ordinary Fiber Bragg Grating(FBG) sensor strain measurement system, which uses Fabry-Perot filter for scanning wavelength, has limitation for application because of hysteresis characteristics of PZT element in the filter, slow scan rate of the filter and the high cost of system. We proposed and experimented a multiple FBG sensor system using light emitting diode(LED) as a light source and adapting Code Division Multiplexing(CDM) method to separating out individual sensor signal. Output signals for a applied static and dynamic strain and crosstalk levels between sensor signals were measured. The price of the system is very loss and the response speed is very fast. Crosstalk levels between sensor signals below - 30 dB were demonstrated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.2
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• pp.91-95
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• 2012

ZnO thin films were deposited on p-type 4H-SiC substrate by pulsed laser deposition. ZnO nanowires were formed on p-type 4H-SiC substrate by furnace. Ti/Au electrodes were deposited on ZnO thin film/SiC and ZnO nanowire/SiC structures, respectively. Structural and crystallographical properties of the fabricated ZnO thin film/SiC and ZnO nanowire/SiC structures were investigated by field emission scanning electron microscope and X-ray diffraction. In this work, resistance and sensitivity of ZnO thin film/SiC gas sensor and ZnO nanowire/SiC gas sensor were measured at $300^{\circ}C$ with various CO gas concentrations (0%, 90%, 70%, and 50%). Resistance of gas sensor decreases at CO gas atmosphere. Sensitivity of ZnO nanowire/SiC gas sensor is twice as big as sensitivity of ZnO thin film/SiC gas sensor.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.69-74
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• 2020

In this study, we proposed a method for surface profiling aspheric lens molds using a precision displacement sensor with a spatial scanning mechanism. The precision displacement sensor is based on the confocal principle using a broadband light source, providing a 10 nm resolution over a 0.3 mm measurable range. The precision of the sensor, depending on surface slope, was evaluated via Allan deviation analysis. We then developed an automatic surface profiling system by measuring the cross-sectional profile of a lens mold. The precision of the sensor at the flat surface was 10 nm at 10 ms averaging time, while 200 ms averaging time was needed for identical precision at the steepest slope at 25 deg. When we compared the measurement result of the lens mold to a commercial surface profiler, we found that the accuracy of the developed system was less than 90 nm (in terms of 3 sigmas of error) between the two results.

• Korean Journal of Geomatics
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• v.2 no.2
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• pp.139-143
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• 2002

The rational polynomial coefficients (RPC) model is a generalized sensor model that is used as an alternative solution for the physical sensor model for IKONOS of the Space Imaging. As the number of sensors increases along with greater complexity, and the standard sensor model is needed, the applicability of the RPC model is increasing. The RPC model has the advantages in being able to substitute for all sensor models, such as the projective, the linear pushbroom and the SAR. This report aimed to generate a RPC model from the physical sensor model of the KOMPSAT-1(Korean Multi-Purpose Satellite) and aerial photography. The KOMPSAT-1 collects 510~730 nm panchromatic imagery with a ground sample distance (GSD) of 6.6 m and a swath width of 17 km by pushbroom scanning. The least square solution was used to estimate the RPC. In addition, data normalization and regularization were applied to improve the accuracy and minimize noise. This study found that the RPC model is suitable for both KOMPSAT-1 and aerial photography.

• Journal of Surface Science and Engineering
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• v.48 no.6
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• pp.309-314
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• 2015

Multiwall carbon nanotubes are synthesized by using VLS mechanism for the application to $H_2$ gas sensor. MWCNT is not suitable for hydrogen gas sensor due to its low response to the gas. To enhance the gas sensing performance, multiwall carbon nanotubes are coated with $TiO_2$ nanoparticles. Scanning electron microscopy and Transmission electron microscopy showed that the synthesized MWCNT were well dispersed with the diameter and wall thickness of approximately 10-30nm and 5nm, respectively. The MWCNT sensor showed the sensitivities of 1.33-9.5% for the $H_2$ concentration of 100-5000ppm at room temperature. These sensitivities are significantly improved to 6.64-46.65% by coating $TiO_2$ nanoparticles to the MWCNT sensor. The mechanisms of $H_2$ gas sensing improvement of the MWCNT sensor coated with $TiO_2$ nanoparticles are discussed.

• Journal of Sensor Science and Technology
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• v.28 no.3
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• pp.157-163
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• 2019

The LiDAR sensor, which is widely regarded as one of the most important sensors, has recently undergone active commercialization owing to the significant growth in the production of ADAS and autonomous vehicle components. The LiDAR sensor technology involves radiating a laser beam at a particular angle and acquiring a three-dimensional image by measuring the lapsed time of the laser beam that has returned after being reflected. The LiDAR sensor has been incorporated and utilized in various devices such as drones and robots. This study focuses on object detection and recognition by employing sensor fusion. Object detection and recognition can be executed as a single function by incorporating sensors capable of recognition, such as image sensors, optical sensors, and propagation sensors. However, a single sensor has limitations with respect to object detection and recognition, and such limitations can be overcome by employing multiple sensors. In this paper, the performance of an eight-channel scanning LiDAR was evaluated and an object detection algorithm based on it was implemented. Furthermore, object detection characteristics during daytime and nighttime in a real road environment were verified. Obtained experimental results corroborate that an excellent detection performance of 92.87% can be achieved.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.163-164
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• 2009