• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.602-605
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• 2008

The anode sheath structure in the hollow anode of an anode-layer type Hall thruster was numerically computed using a fully kinetic 2D3V Particle-in-Cell and Direct Simulation Monte Carlo(PIC-DSMC) code. By treating both ions and electrons as particles, anode surface region, which is electrically non-neutral, was analyzed. In order to analyze in detail, the calculation code was parallelized using Message Passing Interface (MPI). The code successfully simulated the discharge current oscillation. In the low magnetic induction case, ion sheath appears in the anode surface because ionization is enough to maintain the plasma occurs in the anode hollow. As the magnetic induction increases, main ionization region move to outside of the anode. At the same time, anode sheath voltage decreases. In the high magnetic induction case, electron sheath appears on the anode surface periodically because the ionization occurs mainly in the discharge channel. This anode sheath condition shift can be explained using the simple sheath model.

• 전자공학회논문지A
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• 제32A권7호
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• pp.69-76
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• 1995

A new device structure has been developed for p-i-n switches. In this structure, the phosphorus-diffused n$^{+}$ layter adjacent to the boron-doped anode is used to short the p$^{+}$ anode-channel(i-region). This change in the anode electrode structure results in a significant improvement in the threshold voltage-to-holding voltage($V_{Th}/V_{h}$) ratio, which is due to the suppression of the hold injection from the anode by the n$^{+}$ layer. The shorted anode p-i-n devices of a 100 .mu.m channel length show an extremely high threshold voltage in the 250~300 V range and a low holding voltage in the 5~9 V range. These features of the device are expected to acdelerate their practical application to power switching circuits.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.245-250
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• 2004

The discharge current oscillation has been measured for various hollow anode widths and its axial positions using a 1㎾-class anode layer hall thruster. As a result, there were thresholds of magnetic flux density for stable discharge. The plasma structure inside the hollow anode was numerically analyzed using the fully kinetic 2D3V Particle-in-Cell (PIC) and Direct Simulation Monte Carlo (DSMC) methods. The results reproduced both stable and unstable operation modes. In the stable operation case, which corresponds to the case with low magnetic flux, the plasma penetrated into the hollow anode deeper than the case with higher magnetic flux density case. This suggests that comparably large substantial anode area should contribute to stable operation.

• 전자공학회논문지D
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• 제34D권6호
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• pp.33-42
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• 1997

In this paper, a new structure for a dC plasma display pane(PDP) with a wall-catode and a wall-auxilizry anode has been suggested. The wall-cathode with a sufficient discharge area maximizes the discharge volume. The auxiliary anode surrounding the discharge region makes the effective control of the charged particles possible. We have investigated the cahracteristics of the new cell structure with a 2-dimensional computer simulation and a micro gap discharge system, and compared experimentally with those of previous cell structure. The new cell structure with the wall-cathode and auxiliary wall-anode turned out to have improved luminance, discharge forming time and sustain voltage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1469-1471
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• 1994

This paper describes the structure and electrical characteristics of a shorted anode p-i-n switch. The device showed a significant improvement in the threshold voltage-to-holding voltage ratio, which is due to the suppression of the hole injection from the anode and to the gold gettering at the anode side. The shorted anode devices with a $100{\mu}m$ channel length have a threshold voltage of 300 volts and a holding voltage of 5.5 volts.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.31.2-31.2
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• 2011

We studied a method of manufacturing an anode to restrict contraction in reducing NiO/YSZ by uniformly mixing. In order to mix Ni and YSZ, a sub-micron Ni core surface was coated at high-speed by a mixture of nano-sized YSZ and a spherical core-shell was subsequently formed. The micron-sized core-shell anode powder was then heat treated at $400{\sim}1,450^{\circ}C$ in an air atmosphere and Ni was extruded and synthesized in nano-size. Subsequently, when the nano-sized mixture of the anode was heat treated and maintained at a temperature of $1,450^{\circ}C$, the anode was manufactured, where Ni and YSZ were uniformly distributed with the nano-structure. According to the nano-sized anode powder synthesis process, Ni particles were oxidized at $400{\sim}500^{\circ}C$ and became spherical by surface tension. In the case of the spherical core Ni powder, the heat treatment temperature rose to $1,250^{\circ}C$ and then a gap between the internal and external pressures occurred due to thermal and tensile stresses. A crack subsequently appeared on the surface, and the heat treatment temperature was increased continuously to increase the pressure gap and then the core Ni extruded as a nano-sized powder, Ni and YSZ uniformly distributed. It was found that the anode of 50~200 nm with a consistent structure obtained in this study has electric conductivity that is approximately 3 times larger than that of a commercial anode.

• 한국해양공학회지
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• 제14권2호
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• pp.106-111
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• 2000

Recently it was reported that the life of Al Sacrifical anode is being used in port piers has been significantly shortened compared with the original design life (e.g. average life shortened from 20 years to 13-15 year) Those factors involving these problems mentioned above were seemed to be a quality of anode material and diverse environmental factors such as pH flow rate temperature Dissolved oxygen Chemical oxygen demand and resistivity etcm In this study flow rate and contamination degree(pH) of sea water affecting to sacrificial anode life hve been investigated in terms of electrochemical characteristics of Al alloy sacrificial anode It was known that the lifetime of Al alloy anode was shortened not only by increasing of self-corrosion quantity by varying flow rate of sea water but also by increasing corrosion current density due to the potential difference increment between Al anode and steel structure cathode by varying contamination degree of sea water. Especially when anode current density is from 1mA/cm2 to 3mA/cm2 and flow rate of sea water is under 2m/s anode current efficiency is 90% above However flow rate is over 2m/s anode current efficiency fell down sharply due to erosion corrosion as well as galvanic corrosion.

• 한국분말재료학회지
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• 제24권1호
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• pp.24-28
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• 2017

Silicon alloys are considered promising anode active materials to replace Li-ion batteries by graphite powder, because they have a relatively high capacity of up to 4200 mAh/g, and are environmentally friendly and inexpensive ECO-materials. However, its poor charge/discharge properties, induced by cracking during cycles, constitute their most serious problem as anode electrode. In order to solve these problems, Si-Ge-Al alloys with porous structure are designed as anode alloy powders, to improve cycling stability. The alloys are melt-spun to obtain the rapidly solidified ribbons, and then ball-milled to make fine powders. The powders are etched using 1 M HCl solution, which gives the powders a porous structure by removing the element Al. Subsequently, in this study, the microstructures and the characteristics of the etched powders are evaluated for application as anode materials. As a result, the etched porous powder shows better electrochemical properties than as-milled Si-Ge-Al powder.

• 한국재료학회지
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• 제20권11호
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• pp.592-599
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• 2010

A porous nickel-tin nano-dendritic electrode, for use as the anode in a rechargeable lithium battery, has been prepared by using an electrochemical deposition process. The adjustment of the complexing agent content in the deposition bath enabled the nickel-tin alloys to have specific stoichiometries while the amount of acid, as a dynamic template for micro-porous structure, was limited to a certain amount to prevent its undesirable side reaction with the complexing agent. The ratios of nickel to tin in the electro-deposits were nearly identical to the ratios of nickel ion to tin ion in the deposition bath; the particle changed from spherical to dendritic shape according to the tin content in the deposits. The nickel to tin ratio and the dendritic structure were quite uniform throughout the thickness of the deposits. The resulting nickel-tin alloy was reversibly lithiated and delithiated as an anode in rechargeable lithium battery. Furthermore, the resulting anode showed much more stable cycling performance up to 50 cycles, as compared to that resulting from dense electro-deposit with the same atomic composition and from tin electrodeposit with a similar porous structure. From the results, it is expected that highly-porous nickel-tin alloys presented in this work could provide a promising option for the high performance anode materials for rechargeable lithium batteries.

• 공업화학
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• 제33권6호
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• pp.646-652
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• 2022

Dead ended anode (DEA) 시스템은 수소극(anode) 출구를 막고 압력으로 연료를 공급하는 방식이다. DEA 방식은 시스템 단순화를 통해 연료이용효율과 전력 효율을 향상시킬 수 있다. 하지만 DEA 운전 중 공기극(cathode)에서 수소극으로 질소와 물의 역확산으로 인한 범람(flooding)이 발생한다. 이러한 범람 현상은 연료전지 성능 저하와 전극 열화의 주요 요인이 된다. 따라서 DEA 운전 시 범람을 방지하기 위하여 연료전지 구조와 구성요소가 최적화되어야 한다. 본 연구에서는 DEA 시스템에서 연료전지의 성능과 연료이용효율 향상을 위해 발포 금속을 적용한 다공성 유로에 대한 영향을 조사하였다. 그 결과, 공기극에 다공성 유로를 사용한 경우 효과적인 물 관리로 연료전지 성능과 배출 간격(purge interval)이 개선되었고, 이를 통하여 공기극 유로 구조가 물 역확산에 영향을 미치는 것을 확인하였다. 이에 반해 수소극의 다공성 유로가 연료전지 성능에 미치는 영향은 미미하였다. DEA 시스템에서는 발포 금속 물성이 배출 간격에 영향을 미치며 cell 크기가 큰 발포 금속에서 안정적인 성능을 나타내었다.