• International journal of advanced smart convergence
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• v.8 no.4
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• pp.161-168
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• 2019

Traffic accidents in tunnel can lead to large traffic accidents due to narrow and dark road characteristics. Therefore, special care of the driver is required when is driving in a tunnel. However, accidents can happen at any time. In the event of an accident, a narrow road structure may lead to a second accident. Therefore, all facilities installed inside the tunnel should be allowed to minimize damage in the event of an accident. We confirmed the safety of the collision target through the action of the sedan, Sport Utility Vehicle (SUV) and truck when the vehicle crashed into a stairway installed on the tunnel emergency escape route, and when a concrete barrier or guard rail was installed in front of the stairway. The behavior of the vehicle has resulted in a total of three results: rollover or rollover, change of speed and angle of the vehicle after collision. The sedan and SUV were the most secure when colliding with the guardrail, but considering the truck as a whole, concrete barriers were judged to be the most suitable for minimizing damage from the first accident and reducing the risk of the second accident.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.497-500
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• 2011

The experimental study of thermal stress in the solid rocket engine nozzle with two different materials, SCM-440 and STS-630, was evaluated. SCM-440 has lager temperature increasing rate and higher temperature at the nozzle expansion region than STS-630. Thermal barrier efficiency and endurance of Zirconia coating were evaluated after making two more nozzles coated by Zirconica. Both coated materials showed about 70 percent higher thermal barrier efficiency than uncoated nozzles. Therefore, Zirconia coating using plasma spray method was useful in thermal safety at supersonic nozzle.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.725-732
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• 2006

This study has been started for the development of a refined live load distribution formula that has safety and precision toward I type prestressed concrete girder bridge. This type of bridge is mainly applied to short span bridges that are $25{\sim}40m$ in length. Based on various structure analysis models that are currently being applied as preceding studies for the development of live load distribution method. an analysis of flexural stiffness ratio for barrier and diaphragm has been performed. As the result of parametric analysis for the changes in flexural stiffness ratio, the effect of barrier on load distribution showed as insignificant in all structural analysis models while analyzing the deflection distribution. Also. the deflection distribution of the models with stiffness of 25% in which the diaphragm eccentricity is accounted for as same as the models with stiffness of 100% in which the diaphragm eccentricity is unaccounted for. This results are verified through the comparison with a experimental data.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.952-957
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• 2015

Recently, the interior permanent magnet (IPM) motors for electric vehicle (EV) traction motor are being extensively researched because of its high energy density and high efficiency. The traction motor for EV requires high power and high efficiency at the wide driving region. Therefore, it is essential to fully consider the characteristics of the motor from low speed to high-speed driving regions. Especially, when the motor is driven at high speed, a significant centrifugal force is applied to the rotor. Thus, the rotor must be stably structured and be fully endured at the critical speed. In this paper, aims to examine the characteristics of the IPM motor by adjusting the width of air-barrier according to the permanent magnet position which is critical in designing an IPM motor for EV traction motors and to conduct a centrifugal force analysis for grasping mechanical safety.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.1
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• pp.23-34
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• 2004

To validate the previous conceptual design of cover system, construction of the engineered barrier test facility is completed and the performance tests of the disposal cover system are conducted. The disposal test facility is composed of the multi-purpose working space, the six test cells and the disposal information space for the PR center. The dedicated detection system measures the water content, the temperature, the matric potential of each cover layer and the accumulated water volume of lateral drainage. Short-term experiments on the disposal cover layer using the artificial rainfall system are implemented. The sand drainage layer shows the satisfactory performance as intended in the design stage. The artificial rainfall does not affect the temperature of cover layers. It is investigated that high water infiltration of the artificial rainfall changes the matric potential in each cover layer. This facility is expected to increase the public information about the national radioactive waste disposal program and the effort for the safety of the planned disposal facility.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.57-66
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• 2016

The gut epithelial barrier, which is composed of the mucosal layer and the intestinal epithelium, has multiple defense mechanisms and interconnected regulatory mechanisms against enteric microbial pathogens. However, many bacterial pathogens have highly evolved infectious stratagems that manipulate mucin production, epithelial cell-cell junctions, cell death, and cell turnover to promote their replication and pathogenicity in the gut epithelial barrier. In this review, we focus on current knowledge about how bacterial pathogens regulate mucin levels to circumvent the epithelial mucus barrier and target cell-cell junctions to invade deeper tissues and increase their colonization. We also describe how bacterial pathogens manipulate various modes of epithelial cell death to facilitate bacterial dissemination and virulence effects. Finally, we discuss recent investigating how bacterial pathogens regulate epithelial cell turnover and intestinal stem cell populations to modulate intestinal epithelium homeostasis.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.105-111
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• 2015

Since 2007, Insurance Institute of Highway Safety(IIHS) has conducted the new bumper test using bumper barrier to estimate the repair cost of impacted vehicle. In this study, for the front body FE model of a medium size passenger car analyzes were carried out to optimize the shape of backbeam center reinforcement bracket. First, overlap effect was examined with changing the overlap magnitude and spot welds were added along the backbeam center line for reducing the section shear deformation. Next, for an overlap model design parameter study was performed for the bracket. Thickness effect was examined and an inner reinforcement was added to the bracket. Also, the lower part of bracket was deleted and additionally the bracket length was extended. The results were discussed in terms of backbeam backward deflection, barrier backstop intrusion and weight. Compared with the current design, the final model showed 44.1% bracket weight reduction with 30.0% decrease of backbeam deflection.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.267-270
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• 2021

Long-term experiments have been conducted on two important safety issues: long-term durability of a concrete barrier with the steel reinforcements and gas generation from low-and intermediate-level wastes in an underground research tunnel of a radioactive waste disposal facility. The gas generation and microbial communities were monitored from waste packages (200 L and 320 L) containing simulated dry active wastes. In the concrete experiment, corrosion sensors were installed on the steel reinforcements which were embedded 10 cm below the surface of concrete in a concrete mock-up, and groundwater was fed into the mock-up at a pressure of 2.1 bars to accelerate groundwater infiltration. No clear evidence was observed with respect to corrosion initiation of the steel reinforcement for 4 years of operation. This is attributed to the high integrity and low hydraulic conductivity of the concrete. In the gas generation experiment, significant levels of gas generation were not measured for 4 years. These experiments are expected to be conducted for a period of more than 10 years.

• Journal of Korean Neurosurgical Society
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• v.66 no.2
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• pp.172-182
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• 2023

Objective : The blood-brain barrier (BBB) is an obstacle for molecules to pass through from blood to the brain. Focused ultrasound is a new method which temporarily opens the BBB, which makes pharmaceutical delivery or removal of neurodegenerative proteins possible. This study was demonstrated to review our BBB opening procedure with magnetic resonance guided images and find specific patterns in the BBB opening. Methods : In this study, we reviewed the procedures and results of two clinical studies on BBB opening using focused ultrasound regarding its safety and clinical efficacy. Magnetic resonance images were also reviewed to discover any specific findings. Results : Two clinical trials showed clinical benefits. All clinical trials demonstrated safe BBB opening, with no specific side effects. Magnetic resonance imaging showed temporary T1 contrast enhancement in the sonication area, verifying the BBB opening. Several low-signal intensity spots were observed in the T2 susceptibility-weighted angiography images, which were also reversible and temporary. Although these spots can be considered as microbleeding, evidence suggests these are not ordinary microbleeding but an indicator for adequate BBB opening. Conclusion : Magnetic resonance images proved safe and efficient BBB opening in humans, using focused ultrasound.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.70-77
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• 2021

As IoT technology develops along with the 4th industrial revolution, gas safety products to which IoT technology is applied are being developed. However, since the gas safety system was not allowed, system improvement and operation reliability test for IoT gas safety products are required. This thesis researches IoT fuse cock and smart multi-function meter among IoT gas safety products, and analyzes the empirical data of IoT fuse cock to secure operational reliability data, thereby becoming a leader in IoT gas safety products. It aims to develop gas barrier technology one step further through various test evaluations and methods in the future.