• Nuclear Engineering and Technology
• /
• v.52 no.4
• /
• pp.856-862
• /
• 2020

Defect inspection system for industrial applications takes the important portion. Non-destructive inspection method has been significantly improved. Infrared thermography, as one of method for non-destructive inspection, can provide relatively precise data and quick inspection time. This study, it was performed to measure defect according to the measurement limit of the non-visible areas such as the back surface of the pipe using reflection plate using reflection plate based on Infrared thermography. The materials of the reflection plate were determined in consideration of the space limitation and the thermal characteristics, and defects were detected by the manufactured reflection plate. Detection of defect in non-visible area using the candidate materials for reflection plate was conducted.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.448-451
• /
• 2002

The possibility of using polypyrrole as a drug delivery system(DDS) has been studied using indicate (Phenol red) and substance with therapeutic activity(Sodium salicylate). In aqueous solution, negative potential is applied to polypyrrole then anion(with therapeutic activity) of sodium salicylate is released by redox processes of polypyrrole. The release amount of anionic drugs from polypyrrole is measured by UV-visible spectrometer which can measure UV-absorbance of materials. Electrode area that use for release amount measurement is$50mm^{2}(5{\times}10mm)$,and thickness of polypyrrole membrane is $15{\mu}m$. DC 1V applied in saline solution, the release amount according to time increased gradually. In various electrode area, release amount of anionic drug is directly to electrode area.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.1015-1017
• /
• 2003

Recently, DGPS or RTK-GPS techniques enable us to use satellite based positioning systems with high accuracy. But in urban area, navigation systems suffer from problems such as signal blockage by high-rise buildings, multi-path problems, and so on. So we have to know numbers of visible satellites and quality of signals received at the ground level in urban area as accurate as possible. In this paper, we developed a simulation system called LoQAS [Location service Quality Assessment System, 2002, the University of Tokyo] which can simulate numbers of visible satellites and DOP values using accurate satellite orbital data and 3-D digital map. In this time, we evaluated this system and extended it to deal with reflected signals to assess multi-path problems.

• Korean Journal of Materials Research
• /
• v.20 no.5
• /
• pp.246-251
• /
• 2010

The composite photocatalysts of a Fe-modified carbon nanotube (CNT)-$TiO_2$ were synthesized by a two-step sol-gel method at high temperature. Its chemical composition and surface properties were investigated by BET surface area, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectroscopy. The results showed that the BET surface area was improved by modification of Fe, which was related to the adsorption capacity for each composite. Interesting thin layer aggregates of nanosized $TiO_2$ were observed from TEM images, probably stabilized by the presence of CNT, and the surface and structural characterization of the samples was carried out. The XRD results showed that the Fe/CNT-$TiO_2$ composites contained a mix of anatase and rutile forms of $TiO_2$ particles when the precursor is $TiOSO_4{\cdot}xH_2O$ (TOS). An excellent photocatalytic activity of Fe/CNT-$TiO_2$ was obtained for the degradation of methylene blue (MB) under visible light irradiation. It was considered that Fe cation could be doped into the matrix of $TiO_2$, which could hinder the recombination rate of the excited electrons/holes. The photocatalytic activity of the composites was also found to depend on the presence of CNT. The synergistic effects among the Fe, CNT and $TiO_2$ components were responsible for improving the visible light photocatalytic activity.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.12
• /
• pp.1203-1209
• /
• 2011

In this paper, the degradation evaluation method of VLC (Visible Light Communication) wireless module after high dose rate gamma-ray irradiation using the thermal infrared camera is proposed. First, the heating characteristics of the active devices embedded in the VLC wireless module during the condition of normal operation is monitored by thermal infrared camera. By the image processing technique, the trends of the intensity of the heat emitted by the active devices are calculated and stored. The feature of the blob area including the area of the active devices in the thermal infrared image is extracted and stored. The feature used in this paper is the mean value of the gray levels in the blob area. The same VLC module has been gamma irradiated at the dose rate of about 4.0 kGy/h during 72 hours up to a total dose of 288 kGy. And then, the heating characteristics of the active devices embedded in the VLC wireless module after high dose gamma ray irradiation is observed by thermal infrared camera. The high dose gamma-ray induced degradation of the active devices embedded in the VLC module was evaluated by comparing the mean value of the blob area to the one of the same blob area of the VLC module before the gamma ray irradiation.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.464-467
• /
• 2002

We propose the use of visible scintillation light for monitoring the X-ray CT in the gantry of a diagnostic CT for its performance test and maintenance works. We placed a disk of bare plastic scintillator disk in the gantry opening area of a helical X-ray CT. When we operated the CT, we could observe the emission of blue scintillation light from the scintillator in a dark room. Visible light was identified under all scanning conditions of diagnostic uses. As a result, we observed the direction and the spread of the incident X-ray in the scintillator. We also observed the change of the part of the scintillator where visible light was generated, and the move that took place associating with the rotation of the X-ray tube during one CT scan. On the basis of the observation, we examined the usefulness of the visible scintillation light as a convenient performance-evaluating tool as well as a maintenance tool of the CT.

• Current Optics and Photonics
• /
• v.1 no.2
• /
• pp.90-94
• /
• 2017

Visible light identification (VLID) is a user identification system for a door lock application using smartphone that adopts visible light communication (VLC) technology with the objective of high security, small form factor, and cost effectiveness. The user is verified by the identification application program of a smartphone via fingerprint recognition or password entry. If the authentication succeeds, the corresponding encoded visible light signals are transmitted by a light emitting diode (LED) camera flash. Then, only a small size and low cost photodiode as an outdoor interface converts the light signal to the digital data along with a comparator, and runs the authentication process, and releases the lock. VLID can utilize powerful state-of-the-art hardware and software of smartphones. Furthermore, the door lock system is allowed to be easily upgraded with advanced technologies without its modification and replacement. It can be upgraded by just update the software of smartphone application or replacing the smartphone with the latest one. Additionally, wireless connection between a smartphone and a smart home hub is established automatically via Bluetooth for updating the password and controlling the home devices. In this paper, we demonstrate a prototype VLID door lock system that is built up with LEGO blocks, a photodiode, a comparator circuit, Bluetooth module, and FPGA board.

• Korean Journal of Environment and Ecology
• /
• v.28 no.2
• /
• pp.253-262
• /
• 2014

This study was conducted to find methods of qualitative landscape assessment for vegetational landscapes using ecological analysis. The study site was Seoraksan National Park in Korea. For this study, differing unique landscape resources were categorized and identified according to ecosystems. After identifying the study areas, the relationship between trail visitor preference and the amount of visible overexposure caused by people to the resources was examined. Landscape resources chosen for ecological analysis at Seoraksan National Park were subalpine vegetation community, high mountain rocks, ombrogenous deciduous broadleaf forest in the valley area, edaphic climax community, big tree community, flowering tree dominant community, autumnal tree dominant community and needle-leaf forest in the subalpine area. As a result of the study, it was found that the landscape resources with the highest correlation to visitor trail preference were big tree community area, flowering tree dominant community area, and needle-leaf forest in the subalpine area. As a result of overlapping the analysis of the amount of visible overexposure to the landscape resources and the analysis of preferential use of trails by visitors, guidance for the appropriate season for each trail can be provided. Since a positive correlation exists between certain sections of the natural landscapes and visitor preference, ecological impact on landscape resource ecosystems did not appear to cover wide areas of the trails, but was limited to certain areas preferred by visitors.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.5
• /
• pp.1128-1134
• /
• 2010

Nanocarbon supported Fe/$TiO_2$ composite catalysts were prepared using CNTs (carbon nanotubes) and $C_{60}$ (fullerene) as nanocarbon sources by a modified sol-gel method. The Fe/$TiO_2$-nanocarbon composites were characterized by the BET surface area, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and UV-vis spectra. In comparison with non-nanocarbon doped Fe/$TiO_2$ composites, the nanocarbon supported Fe/$TiO_2$ composites had higher absorption ability with a larger specific surface area, and showed higher photocatalytic activity during the degradation of methylene blue (MB) under visible light. The reasons for the obvious increase of photocatalytic activity indicated that the photoactivity not only benefits from nanocarbon introduced, but also relates to the cooperative effect of the Fe as a dopant.

• Journal of Biosystems Engineering
• /
• v.40 no.1
• /
• pp.47-60
• /
• 2015

Purpose: The purpose of this study was to non-destructively and quickly predict the capsaicinoid content of domestic red pepper powders from various areas of Korea using a pungency measurement system in combination with visible and near-infrared (VNIR) spectroscopic techniques. Methods: The reflectance spectra of 149 red pepper powder samples from 14 areas of Korea were obtained in the wavelength range of 450-950 nm and partial least squares regression (PLSR) models for the prediction of capsaicinoid content were developed using area models. Results: The determination coefficient of validation (RV2), standard error of prediction (SEP), and residual prediction deviation (RPD) for the capsaicinoid content prediction model for the Namyoungyang area were 0.985, ${\pm}2.17mg/100g$, and 7.94, respectively. Conclusions: These results show the possibility of VNIR spectroscopy combined with PLSR models in the non-destructive and facile prediction of capsaicinoid content of red pepper powders from Korea.