• 한국산업융합학회 논문집
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• 제26권5호
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• pp.915-923
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• 2023

As environmental regulations on carbon emissions are strengthened worldwide, the existing internal combustion engine-centered automobile industry is being reformed. In particular, large buses and large cargo trucks are pointed out as one of the main causes of environmental destruction due to excessive carbon emissions. The E-Highway power collection system, which has recently been proposed as a solution, uses the vehicle's battery as a backup power source or regenerative braking, depending on whether the pan head of the pentograph installed in the vehicle is in contact with the overhead line. It is used to store the excess energy generated. However, wear through contact due to continuous contact reduces the current collection effect and causes failure. In this paper, by using the current difference, the horizontal position information of the panhead in contact with the overhead line is acquired, thereby reducing the abrasion of the conductor and the panhead Make it possible to follow the overhead line. The position estimation method proposed in this paper simply configures a device that can detect the position of the overhead line of the pantograph by the difference in resistance. It is economical and has the advantage of reducing the volume. The characteristics of the pantograph estimating the location of overhead lines were analyzed using the difference between the two currents of the current collector, the feasibility of the positioning estimation system was verified through simulations and experiments.

• 한국전기전자재료학회논문지
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• 제23권3호
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• pp.190-193
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• 2010

Various power semiconductor devices have been developed and evolved since 1950s. Among them, IGBT is the most developed power semiconductor device which has high breakdown voltage, high current conduction and suitable switching speed which perform trade-offs between each other. In other words, there are trade-offs between a breakdown voltage and on-state voltage drop, and between on-state voltage drop and turn-off time. In this paper, the new structure is proposed to improve a trade-off between a breakdown voltage and on-state voltage drop. The proposed structure has a trench collector and this trench collector induces an accumulation layer at the bottom of an n-drift region during off-state. And this accumulation layer prevents expansion of depletion layer so that trapezoidal electric field distribution is performed in the n-drift region. As a result of this, breakdown voltage is increased without increasing on-state voltage drop. The electrical characteristics of the proposed IGBT is analyzed and optimized by using representative device simulator, TSUPREM4 and MEDICI. After optimization, the electrical characteristics of the proposed IGBT is compared with NPT IGBT which have the same device thickness. As a result of this, it can be confirmed that the proposed structure increases the breakdown voltage of 800 V than that of the conventional NPT IGBT without increasing the on-state voltage drop.

• 한국입자에어로졸학회지
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• 제12권4호
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• pp.115-126
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• 2016

Numerical analysis was done to evaluate the movement of the particles and the fluid inside of the cyclone-bag hybrid dust collector. Flow discharged from the cyclone in the hybrid particle collector has swirl pattern, and it results in the biased flow to the bag filters and deteriorates the collection performance of the bag filter. The current study is to evaluate the effect of the duct lengths and the baffle arrays in the connection duct by the computational methods. Main concerns of the analysis are how to improve the uniformity of the internal flow between the cyclone and the bag filter. Numerical analysis was done to check the particle removal efficiencies of the system with respect to the flow characteristics which is expressed in RMS values of the upward flow inside of the connection duct. The flow pattern inside of the connection duct is evaluated under different the duct lengths and the baffle arrays. In case of the reference geometry the RMS value of inside flow was 56.7%, and the value was decreased to 30.1% by controlling the lengths of duct. The effects of baffle was also evaluated, the RMS value of flow could be decreased 55.2% and so on. But the pressure drop across the baffles becomes high and the system efficiency becomes lower.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.2067_2068
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• 2009

Resistivity changes and intermetallic growth after thermal aging of Matter tin-plated copper sheet for current collector in fuel cell were investigated to survey the diffusion of Cu into Sn in interface and surface. The results show that the intermetallic growth and resistivity depended on thermal aging temperature and dwell time. In Sn plate on a Cu substrate, $Cu_6Sn_5({\mu})$ and $Cu_3Sn({\varepsilon})$ intermetallics layer were formed at plate/substrate interface. $Cu_6Sn_5({\mu})$ intermetallics layer gradually changed $Cu_3Sn({\varepsilon})$. Moreover Cu get through Sn layer and it was diffused in the surface at $200^{\circ}C$. On the other hand, only $Cu_3Sn({\varepsilon})$ intermetallics layer were formed at plate/substrate interface at $300^{\circ}C$. Consequently, the intermetallics formation, thermal condition and oxidation of surface, causes increase in the resistivity of Tin-plated copper sheet.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권3호
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• pp.18-26
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• 2017

The increasing frequency of droughts has been increasing the necessity of utilizing subsurface dams as reliable groundwater resources in areas where it is difficult to supply adequate agricultural water using only surface water. In this study, we analyzed the current status and actual conditions of five agricultural subsurface dams as well as the effect of obtaining additional groundwater from subsurface dams operated as one aspect of the sustainable integrated water management system. Based on the construction methods and functions of each subsurface dam, the five subsurface dams are classified into three types such as those that derive water from rivers, those that prevent seawater intrusion, and those that link to a main irrigation canal. The classification is based on various conditions including topography, reservoir location, irrigation facilities, and river and alluvial deposit distributions. Agricultural groundwater upstream of subsurface dams is obtained from four to five radial collector wells. From the study, the total amount of groundwater recovered from the subsurface dam is turned out to be about 29~44% of the total irrigation water demand, which is higher than that of general agricultural groundwater of about 4.6%.

• 한국수소및신에너지학회논문집
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• 제20권2호
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• pp.125-132
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• 2009

Cylinder shaped air-breathing PEMFC has been developed to have small volume, low contact resistance and better air accessibility to the open cathode. This cylinder shaped design consists of an anode cylinder with helical flow channel and a cathode current collector with slits. The pressure distribution measurement according to the shapes was performed. The test result indicated that cylinder shaped fuel cell has better pressure distribution compared with the planar shaped fuel cell. The better pressure distribution was connected to the higher performance. The maximum power density of cylinder shaped fuel cell was about 20% higher than the planar shaped fuel cell. The maximum power density of the developed cylinder shaped air-breathing PEMFC with dry hydrogen was $220\;mW/cm^2$ and with humidified hydrogen was $293\;mW/cm^2$.

• 대한전자공학회논문지SD
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• 제41권7호
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• pp.7-12
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• 2004

본 논문에서는 교류전류 집중현상이 고려된 바이폴라 등가모델에서 내부 베이스-컬렉터 캐패시턴스(C/sub μ/)와 외부 베이스-컬렉터 캐패시턴스(C/sub μx/)를 분리해서 추출하는 개선된 방법을 연구하였다. 먼저, 기존 추출방법들의 문제점들을 파악하고, 교류전류 집중 캐패시턴스가 포함된 차단모드 등가회로로부터 개선된 추출방정식들을 유도하였다. 이렇게 추출된 C/sub μx/와 C/sub μx/를 사용하여 모델 된 전류 및 전력이득 주파수 응답곡선들은 기존 추출방법으로 얻어진 곡선보다 측정 데이터와 훨씬 잘 일치되었으며, 이는 개선된 추출방법의 정확도를 증명한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.598-598
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• 2012

Rechargeable lithium-ion batteries have been considered the most attractive power sources for mobile electronic devices. Although graphite is widely used as the anode material for commercial lithium-ion batteries, it cannot fulfill the requirement for higher storage capacity because of its insufficient theoretical capacity of 372 mAh/g. For the sake of replacing graphite, Sn-based materials have been extensively investigated as anode materials because they can have much higher theoretical capacities (994 mAh/g for Sn, 875 mAh/g for SnO, 783 mAh/g for $SnO_2$). However, these materials generate huge volume expansion and shrinkage during $Li^+$ intercalation and de-intercalation and result in the pulverization and cracking of the contact between anode materials and current collector. Therefore, there have been significant efforts of avoiding these drawbacks by using nanostructures. In this study, we present the CVD growth of SnO branched nanostructures on Cu current collector without any binder, using a combinatorial system of the vapor transport method and resistance heating technique. The growth mechanism of SnO branched nanostructures is introduced. The SnO nanostructures are evaluated as an anode for lithium-ion battery. Remarkably, they exhibited very high discharge capacities, over 520mAh/g and good coulombic efficiency up to 50 cylces.

• 한국세라믹학회지
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• 제45권6호
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• pp.368-373
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• 2008

An electrode for supercapacitor using 3-dimensional porous nickel foam as a current collector and cobalt oxide as an active material was prepared and characterized in terms of morphology observation, crystalline property analysis, and the investigation of electrochemical property. The electrode surface showed that the cobalt oxide was homogeneously coated as the crystalline phase of $Co_3O_4$. Cyclic voltammetry for the $Co_3O_4$/nickel foam electrode exhibited higher specific capacitance values (445 F/g at 10 mV/s and 350 F/g at 200 mV/s) and excellent capacitance retention ratio (99% after $10^4$ cycles). It was proved that the nickel foam substrate played the roles in reducing the interfacial resistance with cobalt oxide and in improving the electrode density by embedding greater amount of cobalt oxide within it.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.371-374
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• 2000

The electrochemical properties of LiM $n_2$ $O_4$as a cathode and an anode for the lithium secondary battery were evaluated. When LiM $n_2$ $O_4$ material was used as the cathode with the current collector of aluminum, the 1st specific capacity and the 1st Ah efficiency in LiM $n_2$ $O_4$/lithium cell were 123 mAh/g and 91.7%, respectively The anodic properties of LiM $n_2$ $O_4$ material was also evaluated in the LiM $n_2$ $O_4$/1ithium cell with the current collector of copper. It showed that the LiM $n_2$ $O_4$ was useful as the anode for the lithium secondary battery. During the 1st discharge, a potential plateau was observed at the potential of 0.3 $V_{Li}$ Li+/. The 1st specific charge capacity and the 1st specific discharge capacity were 790 mAh/s and 362 mAh/g, respectively. Therefore, the 1st Ah efficiency was 46%. The discharge capacity was gradually faded with the charge-discharge cycling to about 50th cycles. Thereafter, the discharge capacity was stabilized to about 110 mAh/g.