• 한국수소및신에너지학회논문집
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• 제13권2호
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• pp.110-118
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• 2002

The hydrogen storage vessel having a good heat conductivity along with a simple structure and a low cost for these alloys was designed and manufactured, and then its characteristic properties were studied in this study. The various parts in hydrogen storage vessel consisted of copper pipes and stainless steel of 250 mesh reached the setting temperature after 4~5 minutes, which indicated that storage vessel had a good heat conductivity that was required in application. And also the storage vessel had a good property of hydrogen transport considering that the reaction time between hydrogen and rare-earth metal alloys in storage vessel was found to be within 10 min at $18^{\circ}C$ under 10 atmospheric pressure. It showed that the average capacity of discharged hydrogen volume was found to be $120{\ell}$ for $MmNi_{4.5}Mn_{0.5}$ under discharging conditions of $40^{\circ}C{\sim}80^{\circ}C$ at a constant flow rate of $5{\ell}$/min. It was found that the optimum discharging temperature for obtaining an appropriate pressure of 3atm was determined to be $60^{\circ}C$ for $MmNi_{4.5}Mn_{0.5}$ hydrogen storage alloy.

• 정보저장시스템학회논문집
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• 제3권3호
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• pp.139-143
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• 2007

In recent years new recording media and materials for head-disk interface (HDI) have been developed in order to increase the recording density of storage devices and decrease the cost of production. It is well known that HDI in hard disk drive (HDD) needs high durability and stability. The tribological characteristic of commercialized HDI systems is an important indicator of the HDD reliability. In this study, experimental investigation on the wear coefficient of commercialized hard disk slider pads was performed. The slider was placed on top of a hard disk and allowed to slide for a set distance. The wear of the pads was measured after the sliding tests. The result showed that the micro-bumps in commercialized HDD have extremely low wear coefficient of $10^{-11}$. The results of this work may be used for further development of the HDI technology for HDD.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.338-341
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• 2005

This paper proposes a control system for a Galvano meter which can be used in angle multiplexing for a holographic data storage. Due to the small angle multiplexing selectivity and the exposure/delay time of a CCD camera, the system needs to be controlled to satisfy the performance specification. First, the mathematical model is derived by combining the electrical and mechanical dynamic equations. Then, the obtained model was tuned by the experiments. Finally, a PID controller using DSP was designed and was applied the holographic system. From this approach, we successfully meet the performance specification.

• 한국식품조리과학회지
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• 제32권1호
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• pp.44-49
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• 2016

Organic acid fermentation by yeast an important in the flavor and aroma. June 19th brewing each by each of the kinds of yeast (Instaferm, Instaferm red, La parisienne, La parisienne red, Fermivin, Safbrew wb-06, Safele s-04, Song chun) were analyzed organic acid during storage life. All yeast with reduced organic acid on 4 days. On 10 days, Instaferm, Instaferm red, La parisienne, La parisienne red, Fermivin yeast with the increased organic acid but on 19 days these reduced organic acid and maintain to 28 days. However use of Safbrew wb-06, Safele s-04, Song chun yeast the organic acid at storage and maintain organic acid content to 28 days. The variation of each organic acid during storage life characteristic of the yeast.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권1호
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• pp.15-22
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• 2001

In this paper, a VSC(Voltage Sag Corrector) is discussed for the purpose of power quality enhancement. A fast detecting technique of voltage sag is accomplished through the detection of instantaneous value on synchronous reference frame. A robust characteristic against the noise is available by inserting the first order low pass filter in the detection circuit. The formula and the filter design process is described properly with the mathematical equations. Because the VSC system supply the active power to load, it is required to design the proper size of the energy storage system, In this paper, the capacitor bank is used as an energy storage system, and the size of the capacitor is designed from the point of view of input/output energy as the output power rating and the amplitude and duration time of the voltage sag. The simulation is accomplished by PSCAD/EMTDC.

• 대한안전경영과학회지
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• 제8권3호
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• pp.103-114
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• 2006

A cross docking operation involves multiple trucks (known as inbound trucks) that deliver items from suppliers to a distribution center and multiple trucks (known as outbound trucks) that ship items from the distribution center to customers. Based on customer demands, an inbound truck may have its items transferred to multiple outbound trucks. Similarly, an outbound truck can receive its consignments from multiple inbound trucks. A unique characteristic of a cross docking system is the absence or prohibition of long term storage of items at the distribution center. Items delivered to the distribution center from suppliers are shipped to customers as soon as possible without being placed in storage in the distribution center. The objective of this paper is to develop the optimal operational strategy for finding the best truck docking sequence for both inbound and outbound trucks in order to minimize total operation time where a temporary storage area is not available in a cross docking system.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.280-286
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• 2018

A sensorless active damping scheme for LCL filters in grid-connected parallel inverters for battery energy storage systems is proposed. This damping method is superior to the conventional notch filter and virtual damping methods with respect to robustness against the variation of the resonance of the filter and unnecessary additional current sensors. The theoretical analysis of the proposed damping method is explained in detail, along with the characteristic comparison to the conventional active damping methods. The performance verification of the proposed sensorless active damping method shows that its performance is comparable to that of the conventional virtual damping method, even without additional current sensors. Finally, simulation and experimental results are provided to examine the overall characteristics of the proposed method.

• 정보저장시스템학회논문집
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• 제11권2호
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• pp.26-30
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• 2015

Recently, military vehicles are driven with a lot of electronic devices such as radar, antenna, and information storage devices. However, the military vehicles can be exposed to impact easily. Therefore, they have to be designed robustly in order to ensure the stability of the vehicle and the electronic devices. To achieve that, the dynamic behaviors of the military vehicle should be exactly identified. Therefore, in this research, dynamic behaviors of the vehicles were identified by carrying out road tests and we constructed finite element model to analyze the dynamic characteristics of the vehicle.

• 전기학회논문지
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• 제66권6호
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• pp.905-910
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• 2017

As the development of BESS(Battery Energy Storage System), the application of BESS in load frequency control is considered as effective method. So, KEPCO(Korea Electric Power Corporation) have installed about 236MW ESS for GF(Govner Free) function from 2014. In this paper, we implemented Simulink Model for KEPCO GF ESS and analyzed one year historical operation data generated by Simulink model and actually measured frequency data. The operation results were divided into action for maintaining SOC and frequency. In addition, we also analyzed cycle life of GF ESS using two ESS cycle life model. We concluded the ESS cycle life models are not appropriate, because Most of the SOC swing in operation results are below 10%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.539-540
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• 2006

In this paper, We examine that characteristics of formative electret with polymer film and electric charge storage using grid corona discharge. compound polymer of fluorine resin used for material in electret because of high electric charge accumulation, excellent electrical and physical characteristic. All experiments were carried out with circular samples of $Teflon^(R)FEP$ film, 12.5[${\mu}m$] thick. As experiment variables, we used voltage, electrode thickness, discharge electrode gap, and discharge time. According to this variables, we studied on characteristics of formative electret and electric charge storage. Additionally we make a comparative study of the result between the grid corona discharge and needle electrode discharge.