• Journal of the Korean Electrochemical Society
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• v.14 no.4
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• pp.214-218
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• 2011

The electrochemical characteristics and performance of redox flow battery using the soluble lead has been evaluated. Cyclic voltammetry was performed on the materials to evaluate deposition and dissolution of lead and lead dioxide. In the negative region, a reduction peak is not observed, and on the reverse scan, on-set voltage is observed at -0.47 V(vs SCE). In the positive region, the distinct peak is observed on the forward and reverse scan. The charge/discharge experiments were carried out graphite electrode in the beaker cell. The charging(deposition) of lead occurs at around 0.5 V(vs SCE) and discharging(dissolution) of lead occur at around 0.25 V(vs SCE). The potential difference is about 0.25 V. The charging(deposition) of dioxide lead is at 1.77 V(vs SCE) and discharging(dissolution) is at around 0.95 V(vs SCE) during first cycle. On subsequent cycles, the charging of dioxide lead starts at below 1.5 V(vs SCE), after a period the voltage increase to 1.7 V(vs SCE). The voltage of discharging is stable at around 1.0 V(vs SCE).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1935-1946
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• 2013

In this study, the behavior characteristics of bent pile structures with varying cross-section was examined through the measured results of field load test. A framework for determining the bending stress is calculated based on the stresses in the circumference of the pile using 3D finite element analysis. It is found that the bending stress near the pile-column joint changes rapidly and fracture zones occurs easily at variable cross-sections in bent pile structures. Also, the optimized column-pile diameter ratio was analyzed through the relationship between the column-pile diameter ratio and lateral crack load ratio. Based on this study, the optimized column-pile diameter ratio can be obtained near the inflection point of the curve between the column-pile diameter ratio and lateral crack load ratio. Therefore, a present study by considering the optimized variable cross-section condition would be improved bent pile structures design.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.277-291
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• 2003

This study was designed to examine the kinematic factors in the phase during the marche fente motion. For this study, the subjects were 5 elite male fencing players. The direct linear transformation (DLT) method was used in calculating 3-D coordinate of the digitized body parts. The cubic spline function was used for smoothing and the kinematic data for displacement, velocity, angle variables were calculated for Kwon3d ver 2.1. And the following conclusions were drawn; 1. It show that the marche phase appeared to longer time than the pante phase In the performance time. For the fast attack, it showed that the subjects should be moving in a short stride width. 2. For a fast and stable movement posture in the marche phase, the vertical change of COG must be maintain the same position as possible, but all subjects appeared to decrease the COG because of a excessive the knee flection. 3. In the COG velocity change, all the subjects showed to the same change in both the marche and the fente phase. However in the attack extremity velocity, it increased velocity in order of upper arm, fore arm, and hand in the marche phase, but it showed different velocity among each subjects at the moment of stabbing. So that in order to do effective stabbing, they have to extend their upper extremity max and do faster the distal segment than the proximal segment. 4. It showed to take a fast and stable movement, because some subjects showed the big anteroposterior angle of the trunk flexed max shoulder angle and elbow angle of their attack arm and the other upper extremity.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.349-356
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• 2010

In this study, a new design method of pile bent structure considering plastic hinge was proposed on the basis of the beam-column model. Based on the analysis results, it is found that the positioning of plastic hinge on the pile bent structure was influenced by nonlinear behavior of material and p-$\Delta$ effect. Moreover, concrete cracking began to occur at the joint section between the pile and column in case of pile bent structure with different cross-sections. The plastic hinge can be developed on the pile bent structure when large displacement was occurred, and pile bent structures can be maintained well only if it is developed on the column part. Therefore, in this study, the optimized cross-section ratio between column and pile was analyzed to induce the plastic hinge at the joint section between the pile and column. Based on this, the optimized diameter ratio of pile and column can be obtained below the inflection point of the bi-linear curve depending on the relations between column-pile diameter ratio($D_c/D_p$) and normalized lateral cracking load ratio($F/F_{Dc=Dp}$). And through this study, it is founded that in-depth limit($L_{As}$=0.4%) normalized by the pile length($L_P$) are proportionally decreased as the pile length($L_P/D_P$) increases up to $L_P/D_P$=17.5, and beyond that in-depth limit converges to a constant value. Finally, it is found that the proposed limit depth by taking into account the minimum concrete-steel ratio would be more economical design of the pile bent structure.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.346-349
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• 2007

치밀한 $CuInSe_{2}$ (CIS) 태양전지용 광흡수층을 제조하기 위해 상용되는 출발물질을 이용하여 비진공방식인 paste coating 법으로 CIS 막을 제조하였다. 먼저 치밀한 CIS 막 제조를 위해 $Cu_{2}Se$의 액상 거동을 관찰하였다. 이러한 $Cu_{2}Se_{2}$의 액상거동을 위해 Se 분위기에서 Se 증발온도, 기판온도, 열처리시간 등을 다양하게 변화 시켰으며, Se 증발온도 $450^{\circ}C$, 기판온도 $550^{\circ}C$, 열처리시간 30분 그리고 수송가스 ($N_{2}$)를 20 sccm으로 최적조건을 형성하였다. 이러한 최적조건을 바탕으로 치밀한 CIS막을 위해 two-zone RIP (rapid temperature process) 방법으로 Se 분위기 안에서 셀렌화를 위한 열처리를 행하였다. 셀렌화를 위해 다양한 열처리시간에 따라 형성된 CIS 막은 CIS 광흡수층과 Mo 박막 사이에서 $MoSe_{2}$ 층이 형성되었지만, 균일한 CIS 막을 얻었으며 업자성장과 치밀화 거동을 관찰 하였다. 또한, CIS 막의 치밀화를 위해 Se 증발온도와 열처리시간을 고정하고 기판온도를 $600^{\circ}C$로 증가시켜 $Cu_{2}Se$의 액상거동을 관찰하였다. $600^{\circ}C$에서 형성된 CIS 막은 기판온도 $500^{\circ}C$의 시편보다 입자성장과 치밀화가 되었으나 기판으로 사용하는 soda-lime glass의 휨 현상이 발생하였다.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.3
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• pp.42-52
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• 2010

The purpose of this study is to produce digital elevation model (DEM) in the Jebu tidal flat, one of the west coast of the Korean Peninsula, by means of photogrammetric techniques from aerial digital stereo-images. Produced DEM would be become the fundamental data for change detection of the sediment and erosion. To do so, epipolar line is established by relative orientation. Area-based matching is then carried out based on this line and matching size according to surface property of tidal flat after a classified image is produced from reflectance and texture of the surface. As the results, DEM generated by the proposed method showed subtle changes in height more precisely than DEM using the fixed matching size and DEM by the commercial S/W in the region, such as tidal flats having few level differences.

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.33-36
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• 2008

In the present study, impedance spectrometry has been used for predicting State-of-Charge (SoC) of gel type, Valve Regulated Lead Acid (VRLA), battery. The impedance measurements of VRLA battery (2V/1.2 Ah) at various SoC were made over the frequency range from 100kHz to 10mHz with an amplitude 10 mV. The impedance parameters have been evaluated by the analysis of the data using an equivalent circuit and a complex non-linear least squares (CNLS) fitting method. The charge transfer resistance values and double layer capacitance values of the positive electrode were higher than those of the negative electrode. The gel resistance values increased with decreasing in SoC. This indicates that the gel resistance is an important parameter for predicting SoC of VRLA battery.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.133-142
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• 2008

AGV systems are widely used to increase the flexibility and the efficiency of the material handling systems. AGV systems are one of critical factors which determine the overall performance of the manufacturing systems. To this end, the optimal design for AGV systems is essential. Commercial simulation software is often used as an analysis tool during the design of AGV systems, however a series of procedures are desirable to simplify the analysis processes. In this paper, we present and develop the architecture for unidirectional AGV systems simulator which is able to consider approximate optimal unidirectional flow path and various operational parameters. The designed AGV systems simulator is based on JAVA, and it is developed to support designing approximate optimal unidirectional network by using Tabu search method. In addition, it enables users to design and evaluate AGV systems and to analyze alternative solutions easily. Simulation engine is consists of layout designer, AGV operation plan designer, and integrated AGVS layout designer. Users enter their system design/operation information into input window, then the entered information is automatically utilized for modeling and simulating AGV systems in simulation engine. By this series of procedures, users can get the feed back quickly.

• Journal of the Korean Electrochemical Society
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• v.13 no.2
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• pp.128-131
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• 2010

Graphite sheet electro-deposited with lead was evaluated as a possible candidate for current collectors of lead acid batteries. Cyclic voltammetry was performed on the materials to evaluate the electrochemical properties. The graphite sheet electro-deposited with lead is electrochemically stable in the cathodic potential sweep. However, in the anodic potential sweep, the graphite sheet electro-deposited with lead is electrochemically unstable due to the oxygen evolution and the intercalation of sulfuric acid. Lead acid batteries were prepared by using a graphite sheet and a cast grid as current collectors for anode and performance test using those batteries was carried out. A lead acid battery with graphite sheets showed higher capacity and energy density than a conventional lead acid battery with cast grid.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.211-218
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• 2008

The performance of positive plates depends on the structure of the lead dioxide active mass. The positive active materials (PAM) consists of a skeleton, built up of agglomerates and macropores. Agglomerates, in their turn, comprise particles and micropores. This paper described a study conducted to determine the effects of different soaking times between the acid fill and formation stages of the tubular plate production. For the positive plates a lead oxide were filled into tubular bag with a red lead. After filling the positive plates were soaked in $H_2SO_4$ solution. X-ray diffraction(XRD), scanning electron microscopy(SEM) and electrical testing had been used to study the compositional and morphological aspects of the positive active material(PAM) just prior and after formation. Results indicate that PAM compositions were effected by the soaking time and acid density of $H_2SO_4$ solution. It can be seen that as the soaking time duration increases, $\alpha$-PbO, $Pb_3O_4$, and Pb were all gradually sulphating. Composition of 3BS reached a maximum at around 3 h duration and $H_2SO_4$ of sp. gr. 1.10 on soaking. This results would suggest that the most beneficial conditions for soaking were the $H_2SO_4$ of sp. gr. 1.10 and 2 to 6 h of soaking.