• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.160-169
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• 2018

Background: This study aims to develop an integrated optical system that can simultaneously or selectively measure the signals obtained from radioluminescence (RL), thermoluminescence (TL), and optically stimulated luminescence (OSL), which are luminescence phenomena of materials stimulated by radioactivity, heat, and light, respectively. The luminescence mechanism of various materials could be investigated using the glow curves of the luminescence materials. Materials and Methods: RL/TL/OSL integrated measuring system was equipped with a X-ray tube (50 kV, $200{\mu}A$) as an ionizing radiation source to irradiate the sample. The sample substrate was used as a heating source and was also designed to optically stimulate the sample material using various light sources, such as high luminous blue light emitting diode (LED) or laser. The system measured the luminescence intensity versus the amount of irradiation/stimulation on the sample for the purpose of measuring RL, TL and OSL sequentially or by selectively combining them. Optical filters were combined to minimize the interference of the stimulation light in the OSL signal. A long-pass filter (420 nm) was used for 470 nm LED, an ultraviolet-pass filter (260-390 nm) was used for detecting the luminescence of the sample by PM tube. Results and Discussion: The reliability of the system was evaluated using the RL/OSL characteristics of $Al_2O_3:C$ and the RL/TL characteristics of LiF:Mg,Cu,Si, which were used as dosimetry materials. The RL/OSL characteristics of $Al_2O_3:C$ showed relatively linear dose-response characteristics. The glow curve of LiF:Mg,Cu,Si also showed typical RL/OSL characteristics. Conclusion: The reliability of the proposed system was verified by sequentially measuring the RL characteristics of radiation as well as the TL and OSL characteristics by concurrent thermal and optical stimulations. In this study, we developed an integrated measurement system that measures the glow curves of RL/TL/OSL using universal USB-DAQs and the control program.

• Journal of Acupuncture Research
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• v.36 no.3
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• pp.147-153
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• 2019

Background: The aim of this study was to investigate the safety and analgesic effects of Datura Flos pharmacopuncture (DFP). Methods: The analgesic effects of DFP were assessed using mechanical (hot plate), chemical (formalin test), and thermal (von Frey filament test) pain tests. Forty male Sprague Dawley rats were assigned randomly into DFP (75 mg/kg, 150 mg/kg), lidocaine 0.5%, or normal saline group for treatment on Kl3. Gross pathology, histopathology, biochemistry and hematology were performed. Results: In the hot plate test, DFP at a high dose (HDDFP; 150 mg/kg) produced a significant analgesic effect, at 10 and 20-minutes post injection (p < 0.01). Low dose DFP (LDDFP; 75 mg/kg) also showed an analgesic effect at 10 minutes post injection (p < 0.01). In the formalin test, HDDFP produced an analgesic effect, for 0-10 and 10-20 minutes (p < 0.01) post treatment, whereas LDDFP showed analgesic effects between 10-20 minutes (p < 0.05). In the von Frey filament test, DF-H produced an analgesic effect, 10 (p < 0.01) and 20 minutes post treatment (p < 0.05). LDDFP showed analgesic effect at 10 minutes (p < 0.05). In the acupuncture response test, HDDFP produced an analgesic effect at 10 minutes post treatment (p < 0.05). DF-H did not cause any anatomical changes to the liver or kidney and there were no abnormalities in biochemistry or hematology. Conclusion: DF-H was not toxic and provided short term analgesia, suggesting it may be useful in the management of pain.

• Advances in nano research
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• v.10 no.2
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• pp.151-163
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• 2021

The main target of this study is to investigate nonlinear transient responses of moving polymer nano-size plates fortified by means of Graphene Platelets (GPLs) and resting on a Winkler-Pasternak foundation under a transverse pressure force and a temperature variation. Two graphene spreading forms dispersed through the plate thickness are studied, and the Halpin-Tsai micro-mechanics model is used to obtain the effective Young's modulus. Furthermore, the rule of mixture is employed to calculate the effective mass density and Poisson's ratio. In accordance with the first order shear deformation and von Karman theory for nonlinear systems, the kinematic equations are derived, and then nonlocal strain gradient scheme is used to reflect the effects of nonlocal and strain gradient parameters on small-size objects. Afterwards, a combined approach, kinetic dynamic relaxation method accompanied by Newmark technique, is hired for solving the time-varying equation sets, and Fortran program is developed to generate the numerical results. The accuracy of the current model is verified by comparative studies with available results in the literature. Finally, a parametric study is carried out to explore the effects of GPL's weight fractions and dispersion patterns, edge conditions, softening and hardening factors, the temperature change, the velocity of moving nanoplate and elastic foundation stiffness on the dynamic response of the structure. The result illustrates that the effects of nonlocality and strain gradient parameters are more remarkable in the higher magnitudes of the nanoplate speed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.2
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• pp.37-47
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• 2022

The Act on the Punishment of Serious Accidents to Prevent Large-scale Disasters, including Ferry Sewol and Taean Thermal Power Plant, passed the National Assembly on January 8, 2021, and has been in effect since January 27, 2022. However, the law, in which the representative of the headquarters is unlimitedly responsible for each worker's accident, is somewhat unreasonable at a time when a company owns dozens to hundreds of construction sites due to the nature of the construction industry. I agree with the purpose of enacting the law to reduce chronic serious accidents at construction sites, but it is necessary to carefully reconsider the implementation of the law in that punishment alone cannot achieve industrial safety. Previous studies focused on revising the Occupational Safety and Health Act, but there are few studies on the impact on the construction industry after the implementation of the Serious Accident Act. Therefore, this study attempts to derive problems related to the application of the Serious Accident Act and present improvement measures. To this end, after analyzing previous studies, SWOT analysis was performed by applying the Delphi method to derive strengths, weaknesses, opportunities, and threats. In addition, the results of two surveys of safety experts such as public institutions, academia, and companies were reflected, and its countermeasures were presented as follows. S/O strategy: establishing on-site execution capabilities of health and safety management system; W/O strategy: expanding legal and system execution checks; S/T strategy: establishing a risk response system; W/T strategy: expanding consulting by external specialized institutions

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.24-29
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• 2021

Recently, owing to the high demand for eco-friendly cars in the automotive industry, noise and vibrations have become major challenges. The use of laminated damping steel is increasing in response to these demands. Laminated damping steel is primarily used in sound insulation plates. The vibration energy is converted into thermal energy due to the viscoelastic resin being located between two steel sheets and being able to damp the vibrations when an external force, such as, noise or vibration is applied to the steel plate. Laminated damping steel is chiefly applied to dash panels in automotive body parts, and because of its structure, junction technology for bonding with other components is necessary. However, there has not been sufficient research conducted on junctions. In this study, regardless of the electrode shape, in the range of 4.0 ~ 8.0 kA welding current, the same welding force and welding time were applied which were 2.8 kN and 200 m/s (12 cycles) and the tensile shear load and nugget size were analyzed after the resistance spot welding between different materials of laminated damping steel with a thickness of 1.035 mm. The results show that in the range of 5 ~ 8 kA welding current, 1.035 mm laminated damping steel meets the MS181-15 standard, which is the technical standard of Hyundai-Kia Motors.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.2
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• pp.119-128
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• 2022

Recent advancement of Internet of Things (IoT) and energy harvesting technology enable realization of flexible thermoelectric energy harvester (f-TEH), with technological prowess for use in biomedical monitoring system integrated applications. To expand a flexible thermoelectric energy harvesting platform, the f-TEH must be required for optimized flexible thermoelectric materials and device structure. In response to these demands related to thermoelectric energy harvesting, many research groups have investigated various f-TEHs applied as a power source for wearable electronics. As a key member of the f-TEH, film-based f-TEHs possess significant applicability in research to realize self-powered wearable electronics, owing to their excellent flexibility, low thermal conductivity, and convenient fabrication process. Thus, based on the rapid growth of thermoelectric film technology, this review aims to overview comprehensively the f-TEH made of various inorganic/organic thermoelectric materials including developed fabrication methods, high thermoelectric performance, and wide-range applications.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.79-84
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• 2022

As various flexible display products are released, the demand for high-performance colorless and transparent polyimide (CPI) film is continuously increasing. The primary purpose of this study is to establish a systematic procedure for optimizing the optical performance of CPI films by applying the response surface method. After selecting three key factors (monomer type, stirring time for varnish synthesis, and maximum temperature of vacuum furnace for film production) affecting optical performance based on experiences and references, CPI films were manufactured according to the experimental sequence designed by the central composite design, and then the yellowness index (YI) and optical transmittance (Tr) of the films were measured. When producing a CPI film by pouring varnish into a petri dish, the change in optical properties according to thickness should be considered, and there was a meaningful linear relationship between YI and Tr. The species of monomer and the maximum temperature were the critical factors that had an influence on YI and Tr, respectively. It is expected that the procedure proposed in this study can serve as a starting point for CPI film optimization studies considering the other factors that were not considered and responses such as thermal properties.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3133-3139
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• 2023

Neutron imaging technology as a means of non-destructive detection of materials is complementary to X-ray imaging. Silicon photomultiplier (SiPM), a new type of optical readout device, has overcome some shortcomings of traditional photomultiplier tube (PMT), such as high-power consumption, large volume, high price, uneven gain response, and inability to work in strong magnetic fields. Its application in the field of neutron detection will be an irresistible general trend. In this paper, a thermal neutron imaging detector based on ⁶LiF/ZnS scintillation screen and SiPM array readout was developed. The design of the detector geometry was optimized by geant4 Monte Carlo simulation software. The optimized detector was evaluated with a step wedge sample. The results show that the detector prototype with a 48 mm × 48 mm sensitive area can achieve about 38% detection efficiency and 0.26 mm position resolution when using a 300 ㎛ thick ⁶LiF/ZnS scintillation screen and a 2 mm thick Bk7 optical guide coupled with SiPM array, and has good neutron imaging capability. It provides effective data support for developing high-performance imaging detectors applied to the China Spallation Neutron Source (CSNS).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.214-225
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• 2023

Piezoelectric actuators, which utilize piezoelectric crystals or ceramics, are commonly used in precision positioning applications, offering high-speed response and precise control. However, the use of low-performance ceramics and expensive single crystals is limiting their versatile use in the actuator market, necessitating the development of both high-performance and cost-effective piezoelectric materials capable of delivering higher forces and displacements. The use of textured Pb (lead)-based piezoelectric ceramics formed by so-called templated grain growth method has been identified as a promising strategy to address the performance and cost issue. This review article provides insights into recent advances in texturing Pb-based piezoelectric ceramics for improved performance in actuation applications. We discussed the relevant issues in detail focusing on current challenges and emerging trends in the textured piezoelectric ceramics for their reliability and performance in actuator applications. We discussed in detail focusing on current challenges and emerging trends of textured piezoelectric ceramics for their reliability and performance in actuator applications. In conclusion, the article provides an outlook on the future direction of textured piezoelectric ceramics in actuator applications, highlighting the potential for further success in this field.

• Journal of Marine Life Science
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• v.2 no.1
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• pp.34-38
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• 2017

FK506BP (FK506 binding protein 12) is a small peptide with a single FK506BP domain. It is involved in suppression of immune response, oxidative stress and inflammation. The purpose of this study was to investigate the gene expression of FK506BP in red seabream (Pagrus major) exposure to low water temperature (8℃, 33 psu) and low salinity (20℃, 10 psu). Results showed that, the expression of FK506BP was significantly increased in the experiment groups, such as low water temperature (8℃, 33 psu), and low salinity (20℃, 10 psu). These results suggest that FK506BP was played roles in biomarker gene on the environmental stress such as water temperature and salinity.