• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2002.05a
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• pp.138-138
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• 2002

Oxidative stress has been associated with a number of diseases in human. Among the sources that can generate oxidative stress, it has been reported that iron can generate reactive oxygen species (ROS)with thiol. In iron overload state, increased thiol levels in plasma appeared to be associated with human mortality. In this study we examined whether iron could interact with thiols in plasma, generating ROS. In human plasma, unlike with Fe(III), Fe(II) increased lucigenin-enhanced chemiluminescence in concentration-dependent manner, and this was inhibited by SOD. Boiling of plasma did not affect chemiluminescence induced by Fe(II). Hovever, thiol depletion in plasma by pretreatment with N-ethylmaleimide (NEM)decreased Fe(II)-induced chemiluminescence significantly, suggesting that Fe(II) generated superoxide anion by the nonenzymatic reaction with plasma thiol. Consistent with this findings, albumin, the major thiol contributor in plasma, also generated ROS with Fe(II) and this generation was inhibited by pretreatment with NEM. Treatment with Fe(II) to plasma resulted un significant reduction of oxygen radical absorbance capacity (ORAC) value, suggest that total antioxidant capacity could diminished in iron overload state. In conclusion, In iron overload state, plasma may be affected by oxidative stress mediated by nonenzymatic reaction of Fe (II)with plasma thiol.

• Corrosion Science and Technology
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• v.22 no.6
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• pp.466-477
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• 2023

The increasing demand for high-performance energy storage systems has highlighted the limitations of conventional Li-ion batteries (LIBs), particularly regarding safety and energy density. All-solid-state batteries (ASSBs) have emerged as a promising next-generation energy storage system, offering the potential to address these issues. By employing nonflammable solid electrolytes and utilizing high-capacity electrode materials, ASSBs have demonstrated improved safety and energy density. Automotive and energy storage industries, in particular, have recognized the significance of advancing ASSB technology. Although the use of Li metal as ASSB anode is promising due to its high theoretical capacity and the expectation that Li dendrites will not form in solid electrolytes, persistent problems with Li dendrite formation during cycling remain. Therefore, the exploration of novel high-performance anode materials for ASSBs is highly important. Recent research has focused extensively on alloy-based anodes for ASSBs, owing to their advantages of no dendrite formation and high-energy density. This study provides a comprehensive review of the latest advancements and challenges associated with alloy-based anodes for ASSBs.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.995-1004
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• 1998

This paper presents an implementation of model checking tool for LTS process specification, which checks deadlock, livelock and reachability for the state and action. The implemented formal checker using modal mu-calculus is able to verify whether properties expressed in modal logic are true on specifications. We prove experimentally that it is powerful to check, safety and liveness for the state and action on LTS. The tool is implemented by $C^{++}$ language and runs on IBM PC under Windows NT.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.125-131
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• 2011

TSI(Technical Specification for Interoperability) is the highest technical specification in the Europe Railway and is composed by assessment items and essential requirements included by safety, reliability, availability, health, environment protection and technical compatibility. It is used on the research and development in the next generation railway technical. Currently, TSI procedures have been asked to bid for high speed rail business in Europe and Brazil. Also, all the railway systems such as infrastructure, signaling, electric and rolling stock system corresponding with standard of TSI procedures are exported and imported. Recently, Safety Critical System which has been studied on future railway R&D business in Korea is the state of the art train control system. And it is needed for system assessment of TSI procedures before system test and operation. In this paper, basic research is performed for analyzing TSI procedures suitable for the state of the art train control system in Korean railway.

• Smart Structures and Systems
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• v.20 no.3
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• pp.263-272
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• 2017

This paper presents the time response of a mixed vibration system with the viscous damping and the hysteretic damping. There are two ways to derive the time response of such a vibration system. One is an analytical method, using the contour integral of complex functions to compute the inverse Fourier transforms. The other is an approximate method in which the analytic functions derived by Hilbert transform are expressed in the state space representation, and only the effective eigenvalues are used to efficiently compute the transient response. The unit impulse responses of the two methods are compared and the change in the damping properties which depend on the viscous and hysteretic damping values is investigated. The results showed that the damping properties of a mixed damping vibration system do not present themselves as a linear combination of damping properties.

• Journal of the Korea Safety Management & Science
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• v.11 no.4
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• pp.311-317
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• 2009

In this paper deals with behavior of the magnetic abrasive using Ba-Ferrite on polishing characteristics in a new internal finishing of STS304 pipe applying magnetic abrasive polishing. The magnetic abrasive using Ba-Ferrite grain WA used to resin bond fabricated low temperature. And Ba-Ferrite of magnetic abrasive powder fabricated that Ba-Ferrite was crused into 200 mesh. The previous research have made an experiment in the static state the movement of magnetic abrasive grain is nevertheless in the dynamic state. In this paper, We could have investigated into the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.18-25
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• 2005

This study performed finite element analysis on the pipe bend with various bend angles under loading conditions of internal pressure and combined pressure and bending, to investigate the effect of bend angle on the collapse behavior of pipe bend and on the stress state in the bend region. In the analysis, the pipe bends with bend angle of $5\~90^{\circ}$ were considered, and the bending moment was applied as in-plane closing and opening modes. From the results of analysis, it was found that the collapse moment of pipe bend increases with decreasing bend angle. As the bend angle decreases, also, the equivalent stress at intrados region increases regardless of bending mode. Under closing mode bending especially, the increase in stress at intrados is significant so that the maximum stress region moves from crown to intrados with decreasing bend angle.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1995.04a
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• pp.59-64
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• 1995

The impediment in enhancing the ship safety and combating vessel-source marine pollution depends on the combination of the immediate and mediate factors. The former is mainly caused by human errors and failure in compliance with the international convention standards in operation of compliance with the international convention standards in operation of vessel. The latter by the attitudes and activities of some of the flay states taking little responsibilities with appropriate seriousness in policing their fleets due to the lack of implementing capability of adminstrations. So long as there exists a large size of variation in implementing capability of administration between flag states a globally remarked progress cannot expect to be made in assuring the ship safety and preventing the vessel-source pollution Therefore a new regulatory regime is suggested to be adopted by IMO to maintain high standard flag state adminstrations by recommending standard paradigm to member states so that the development of a implementing culture is encouraged and supported.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.351-359
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• 2007

In this study, a hierarchical switching control scheme based on robust control theory is proposed for tracking control of vehicle longitudinal acceleration in the presence of large uncertainties. A model set consisting of four multiplicative-uncertainty models is set up, and its corresponding controller set is designed by the LMI approach, which can ensures the robust performance of the closed loop system under arbitray switching. Based on the model set and the controller set, a switching index function by estimating the system gain of the uncertainties between the plant and the nominal model is designed to determine when and which controller should be switched into the closed loop. After theoretical analyses, experiments have also been carried out to validate the proposed control algorithm. The results show that the control system has good performance of robust stability and tracking ability in the presence of large uncertainties. The response time is smaller than 1.5s and the max tracking error is about $0.05\;m/S^2$ with the step input.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1967-1977
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• 2014

In this paper, for the development of a safe and reliable DC home appliance suitable for DC home power supply system, we classified a number of inherent problems with help of the comparative analysis of existing AC and new DC home appliance. Several new technical problems of DC home appliances are mainly linked to the DC transient state. Among them, this paper concentrates on start-up inrush current problem, uni-polarity problem, and heavy DC load control problem. And to address these problems, we herein present an implementation of robust safety circuits for DC home appliances. Specifically, we investigate several multi-circuit countermeasures and select the best among them through comparative evaluation, based on theoretical, simulational, and experimental results.