• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.49-54
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• 1999

In this paper. we studied cut off characteristics and fire hazard of residual current protective devices(RCD or ELB) for low voltage. The operative time of RCD with grounding resistance was analyzed by using RCD operating tester. The surface structure and composition of insulator were analyzed by using scanning electron microscope(SEM) and energy dispersive x-ray spectroscopy(EDX). The surface of phenol resin showed network structure and void. The spectra shown in EDX analysis are composed not only of the corresponding elements but also of several new spectra, as CK. OK$\alpha$. MgK, SiK. and CaK, which were absent in original material.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.2
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• pp.38-43
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• 2019

Electrochemical etching is a popular process to apply metal patterning in various industries. In this study, the electrochemical etching using a patterned copper layer was proposed to fabricate multilayered structures. The process consists of electrodeposition, laser patterning, and electrochemical etching, and a repetition of this process enables the production of multilayered structures. In the fabrication of a multilayered structure, an etch factor that reflects the etched depth and pattern size should be considered. Hence, the etch factor in the electrochemical etching process using the copper layer was calculated. After the repetition process of electrochemical etching using copper layers, the surface characteristics of the workpiece were analyzed by EDS analysis and surface profilometer. As a result, multilayered structures with various shapes were successfully fabricated via electrochemical etching using copper layers.

• Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.111-121
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• 2024

Particulate matter (PM) is a mixture of microscopic solid inhalable particles including airborne liquid droplets, and it is implicated with several diseases. The eye does not have a protective barrier among the human organs, consequently it get directly exposed to environmental substances such as PM. The scarcity of treatments for damage to the eyesight and the vision and eye structure being closely related to the structure and function of the central nervous system highlights the cruciality of novel therapeutics. In this study was conducted using in vivo zebrafish vertebrate model which is a useful model due to the conserved genes between human. We found that protective effect of Octopus minor extract against particulate matter-induced adverse effects on eye development in zebrafish (Danio rerio) embryos by regulating antioxidant and anti-inflammatory mRNA expression.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2902-2904
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• 1999

Protective relay in power system play a prominent part, Simulators for the relay test were introduced in early 1980's, A number of open loop designs have been developed and Recently, several developments of real-time simulators have been reported. But they are very high cost. And then they are difficult to apply for relay testing in small business. This paper presents the structure and performance of a new pc based simulator for digital protective relay testing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.2
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• pp.155-162
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• 2005

This paper presents an invetigation into the cause of deterioration of wet surrounding RC structures subjected to checmical attacks such as sewage. The antibacterial-reforming agent is developed after determining the permeability of the RC structure. After application of the anitbacterial-reforming agent through SEM, the permeability, compressive strength properties and the micro-structure of the concrete were evaluated for durability. In addition, the antibacterial-reforming agent was combined with a protective coating for the wet surrounding RC structure and evaluated for durability. The combined effect of the antibacterial-reforming agent and the protective coating were evaluated in field tests in both sewer system and tunnel sites.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.297-304
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• 2016

A numerical simulation has been performed for the penetration of a long-rod penetrator into a metal block (ceramic-tile-inserted 4340-steel plate). The impact velocity is 1.5km/s at a normal incidence angle. The first two validations are conducted for a semi-infinite block measuring the depth of penetration (DOP). The material model of ceramic is the JH-2 (Johnson-Holmquist) model. The predicted DOP values are in close agreement with the experimental data. Then, the primary simulation is performed by varying the position of the confined ceramic tile for three types of thickness of ceramic tile. The residual velocity, residual mass and residual kinetic energy of the long-rod are obtained from the simulation. Based on these predicted values, the trend of the ballistic performance of the protective structure is estimated. In addition, the mass efficiency is calculated in order to determine the performance of the ceramic-tile-inserted metal block. Finally, the optimum protective structure is identified.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.255-255
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• 2011

Zinc oxide based thin films have been extensively studied in recent several years because they have very interesting properties and zinc oxide is non-poisonous, abundant and cheap material. ZnO films are employed in different applications like transparent conductive layers in solar cells, protective coatings and so on. Wide industrial application of the ZnO films requires of development of cheap, effective and scalable technology. Typically used technologies don't completely satisfy the industrial requirements. In the present work, we studied effect of the deposition parameters on the structure and properties of ZnO films deposited by DC arc plasmatron. The varied parameters were gas flow rates, precursor composition, substrate temperature and post-deposition annealing temperature. Vapor of Zinc acetylacetone was used as source materials, oxygen was used as working gas and argon was used as the cathode protective gas and a transport gas for the vapor. The plasmatron power was varied in the range of 700-1500 watts. Flow rate of the gases and substrate temperature rate were varied in the wide range to optimize the properties of the deposited coatings. After deposition films were annealed in the hydrogen atmosphere in the wide range of temperatures. Structure of coatings was investigated using XRD and SEM. Chemical composition was analyzed using x-ray photoelectron spectroscopy. Sheet conductivity was measured by 4-point probe method. Optical properties of the transparent ZnO-based coatings were studied by the spectroscopy. It was shown that deposition by a DC Arc plasmatron can be used for low-cost production of zinc oxide films with good optical and electrical properties. Increasing of the oxygen content in the gas mixture during deposition allow to obtain high-resistive protective and insulation coatings with high adhesion to the metallic surface.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.199-206
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• 2021

This paper describes the feasibility and reliability verification of installing a protective structure to protect attack periscopes. The attack periscope is the critical equipment of a submarine to enable the user to monitor surface and air activity, collect navigational data, and detect and identify targets. The attack periscope provides target information acquired through TV, IR camera, and laser range finder to the combat system. In the product improvement program, the upper part of the masts was exposed to the outside of the sail because the existing attack periscope was replaced with a new one. On the other hand, the head sensor can be damaged by floating objects, such as fishing nets, during sea navigation. Therefore, the installation of a protective structure for an attack periscope improved the equipment operation performance. The feasibility and reliability of the installation of the protective structure were verified by examining the influence of URN.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.771-783
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• 2022

In this study, the feasibility of alternative tractor Roll Over Protective Structure (ROPS) designed to evaluate conditions required for testing was confirmed. In accordance with Organization for Economic Cooperation and Development (OECD) code 4, the required load energy of the tractor ROPS was determined. First, the tractor ROPS test was performed and a repeated test was performed using a simplified ROPS as an alternative tractor ROPS. The test procedure is first rearward, second lateral, and last forward based on ROPS. The load test device consists of a load cell that measures force and a LVDT that measures deformation. Precision was confirmed by calculating the relative standard deviation of the simplified ROPS repeated test. Accuracy was analyzed by calculating the mean relative error between the mean measured values in the simplified ROPS test and the tractor ROPS test. As a result, the relative standard deviation was less than 2.5% for force and 3.3% for maximum deformation overall, showed the highest precision in lateral load. The mean relative error value for force measured at the lateral load of simplified ROPS was 0.5%, showing the highest accuracy. In the front load test, the mean relative error of maximum deformation was 20.5%, showing the lowest accuracy. The mean relative error (MRE) was high in the forward load test was because of structural factors of the ROPS. The simplified ROPS model is expected to save money and time spent preparing tractors.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.31-38
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• 2016

In this paper, the deformation-energy curves of the plastic hinges and the vessel bow, which are the major energy dissipation mechanism of a pile protective structures, were estimated, and the parametric study was performed by using those curves to apply the simplified collision model which developed in the previous study. Considered parameters were the mass of slab, the number of piles, the mass of vessel and the collision speed. As results, the difference of energy dissipation mechanism of two pile types (filled and non-filled) were revealed, and the collision behaviors of the protective structures could be tuned by the control of the inertia mass of capping slab. Therefore the simplified collision model can be used in a primary design and optimal design.