• Toxicological Research
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• v.19 no.4
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• pp.285-291
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• 2003

The use of skin whitening agents has been recently increased in various kinds of cosmetic products, although there were some reports that whitening agents might cause allergic contact dermatitis. A murine local lymph node assay (LLNA) has been developed as an alternative to guinea pigs for contact sensitization potential. This study was carried out to investigate the skin sensitization potential of three whitening agents, arbutin, azelaic acid, and kojic acid, by LLNA using a non-radiois-topic endpoint. Female Balb/c mice were exposed topically to a weak allergen, $\alpha$-hexylcinnamalde-hyde (HCA), and three whitening agents following LLNA protocol. Lymph node (LN) weight and cell proliferation in ears and auricular lymph node using bromodeoxyuridine (BrdU) immunohistochemistry were evaluated. LN weights were significantly increased at the HCA group compared to the vehicle control. A weak allergen, HCA elicited 3-fold or greater increase in cell proliferation of lymph nodes as well as increase in cell proliferation of ear as measured by BrdU immunohistochemistry. However, in the case of skin whitening agent groups, there were no significant changes in LN weight and cell proliferation in the ear and lymph node of mice treated with 5, 10 and 20% of three whitening agents compared to the vehicle control. These results show that these three skin whitening agents may not have contact sensitization potentials at tested concentrations in Balb/c mice by LLNA.

• World Technopolis Review
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• v.3 no.3
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• pp.139-152
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• 2014

The current transportation regime is largely based on two alternatives: (1) fixed route public transit, and (2) private ownership of internal combustion engine (ICE) powered vehicles per households. This paper analyzes one possible transportation alternative, Micro Electric Vehicles or MEVs, and compares with the ICE vehicles in terms of social, economic and environmental benefits, especially emphasizing its environmental advantage over ICE vehicles for future sustainability. While some representative models of MEVs exist in a limited market capacity, but global technical standards are generally insufficient and non-homogenous across nations, which restricts the development of the proposed transportation sector. The focus of this paper is to analyze the characteristics and potential benefits of MEVs in economical and environmental perspectives, including development status and technical standards, with a particular focus in the E.U., the U.S., Japan, and Korea. Based on the data of analysis, this paper aims to derive and propose a cooperative and adaptive global policy framework designed to speed up adoption and expansion of the global MEV market, including passenger and utility vehicles. We propose MEV to be a new mobility segment in the global transportation market because of their advantage in environmental impact, sustainability, overall cost of ownership, and safety.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.87-90
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• 2007

Fuel cell power system was developed for high-endurance unmanned aerial vehicle (UAV). Liquid chemical hydride was selected as a fuel due to its high energy density. Liquid storage of the fuel is an ideal alternative solution of the existing compressed hydrogen storage. The fueling system that extracts hydrogen from chemical hydride consists of catalytic reactor, micro-pump, fuel cartridge, separator, and controller. The fuel cell power system including the fueling system and the fuel cell that generates electricity was integrated into a proposed UAV. The performance verification of the fuel cell power system was performed to use as a power plant of the UAV.

• Smart Structures and Systems
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• v.1 no.3
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• pp.235-256
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• 2005

The non-linear behaviour of electrorheological (ER) and magnetorheological (MR) dampers makes it difficult to design effective control strategies, and as a consequence a wide range of control systems have been proposed in the literature. These previous studies have not always compared the performance to equivalent passive systems, alternative control designs, or idealised active systems. As a result it is often impossible to compare the performance of different smart damper control strategies. This article provides some insight into the relative performance of two MR damper control strategies: on/off control and feedback linearisation. The performance of both strategies is benchmarked against ideal passive, semi-active and fully active damping. The study relies upon a previously developed model of an MR damper, which in this work is validated experimentally under closed-loop conditions with a broadband mechanical excitation. Two vibration isolation case studies are investigated: a single-degree-of-freedom mass-isolator, and a two-degree-of-freedom system that represents a vehicle suspension system. In both cases, a variety of broadband mechanical excitations are used and the results analysed in the frequency domain. It is shown that although on/off control is more straightforward to implement, its performance is worse than the feedback linearisation strategy, and can be extremely sensitive to the excitation conditions.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.819-826
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• 2011

The proton exchange membrane fuel cell (PEMFC) is regarded as the most promising alternative power sources for unmanned aerial vehicle (UAV) due to its high energy density and silent operation. Since there are many load changes during UAV flight, thermal management is one of the important factor for the performance of PEMFC. In order to reduce the UAV weight for the stable operation of UAV, thermal management system (TMS) studied in this work does not use the fan but use the air flowing into UAV by UAV flight. In order to develop the passive type heat exchanger (HEX) for 1kW PEMFC, four types of HEXs are fabricated and their cooling performances are compared. The parametric study on the cooling performance of HEXs has performed with the variation of operating parameters such as mass flow rates and inlet temperature of air and coolant. Type 4 has the best performance in every case. This study can be helpful to achieve the optimal design of HEX for PEMFC powered UAV.

• Journal of the Ergonomics Society of Korea
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• v.27 no.3
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• pp.23-32
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• 2008

This study attempts to develop improved ingress and egress in vehicle for disabled wheelchair people who driving is available, after investigating the ingress and egress relation demand and the inconvenient factor in the vehicle. An experiment was performed for that disabled wheelchair people to analyze the characteristics of ingress and egress relation operation through the questionnaire survey and the camera photographing. The results suggest various improvements possibilities in inside handlebar as a main factor. Through analysis of disabled wheelchair person's ingress and egress tendency, the alternative shape and position of inside handlebar are suggested. Also, this paper aimed to draw ingress and egress improvement proposal by executing a verification experiment and collecting the preferences from disabled people.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.6
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• pp.422-426
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• 2018

The lithium-ion battery pack of an electric vehicle (EV) deserves to be considered for an alternative use within smart-grid infrastructure. Despite the long automotive service life, EV batteries retain over 70~80% of their initial capacity. These battery packs must be managed for their reliability and safety. Therefore, a battery management system (BMS) should use specific algorithms to measure and estimate the status of the battery. Most importantly, the BMS of a grid-connected energy storage system (ESS) must ensure that the lithium-ion battery does not catch fire or explode due to an internal short from uncontrolled dendrite growth. In other words, the BMS of a lithium-ion battery pack should be capable of detecting the battery's status based on the electrochemical reaction continuously until the end of the battery's lifespan. In this paper, we propose a new protection algorithm for a dendritic lithium battery. The proposed algorithm has applied a parameter from battery pack aging results and has control power managing.

• Journal of Auto-vehicle Safety Association
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• v.13 no.3
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• pp.102-110
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• 2021

As an alternative to solving safety, environments, and aging problems, ADS (Automated driving system) in the global automotive market is actively being developed as a new growth industry. In time for the appearance of ADS, relevant regulations and assessment programs must also be developed. For example, safety standards for the Level 3 automated driving system were promulgated in December 2019 by the Ministry of Land, Infrastructure and Transport of Korean government. However, assessment programs such as KNCAP for autonomous functions of ADS have not yet been introduced in Korea as well as globally. The autonomous driving functions of ADS at Level 3 or higher must be capable to recognize, judge and respond to objects and events in a wide variety of complex situations. In this paper, we examined and studied the complex situations, considerations and assessment items that ADS must respond to in the interest of safety for passengers, pedestrians and other road users. We hope this paper will be helpful to develop an execution program in the future.

• Journal of Drive and Control
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• v.19 no.2
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• pp.36-44
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• 2022

Hydrogen energy as an alternative source of energy has been receiving tremendous support around the world, and research is being actively conducted accordingly. However, most of the studies focus on hydrogen storage tanks and only are few studies on interpreting the hydrogen filling system itself. In this study, with reference to SAE J2601, a hydrogen fueling protocol, a simulation model was developed that can confirm the behavior of the vehicle's internal tank during hydrogen fueling. With respect to factors such as fuel supply temperature, ambient temperature, and pressure increase rate, the developed model can check the change of temperature and pressure in the tank and the state of hydrogen charging during hydrogen fueling. The validity of the developed simulation model was confirmed by comparing the simulation results with the experimental results presented in SAE J2601.

• Journal of Convergence Korean Medicine
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• v.5 no.2
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• pp.11-16
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• 2023

Objectives: The purpose of this study was to investigate the anti-obesity effects of the aqueous extract of Schizandra chinensis (SC) in menopausal mice. Methods: To induce menopausal obesity, female mice were ovariectomized (OVX) and fed a high-fat diet (HFD; 60% fat, 28% carbohydrates, 14% protein) for 12 weeks. The mice were divided into 6 groups (n = 8): NOR (sham-operated and vehicle-treated), HFD+OVX (vehicle-treated), E2 (17-beta estradiol 50 ㎍/kg-treated), SC1 (1 mg/kg SC-treated), SC10 (10 mg/kg SC-treated), and SC100 (100 mg/kg SC-treated). Samples were orally administered for 6 weeks, after which all experimental mice were sacrificed. Body weight, feeding efficiency, white adipose tissue weight, adipocyte diameter, and fat vacuoles in liver were analyzed. Results: By treating with SC extract, the body weight and feeding efficiency of mice were significantly decreased. The weight of visceral fat tissues was decreased in the SC10 and SC100 groups. Histopathology showed that fat cell diameters of white adipose tissue were also decreased in the SC10 and SC100 groups. Additionally, SC extract regenerated the hepatocyte damage and decreased the size and number of follicular adipocytes Conclusion: In summary, these results suggest that SC has inhibitory effects against menopausal obesity. Schizandra chinensis may be a potential alternative for obesity among female menopausal diseases.