• Journal of the Korean Electrochemical Society
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• v.16 no.4
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• pp.191-197
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• 2013

The one of the cathode material, $Li(Ni_{0.5}Co_{0.2}Mn_{0.3})O_2$, was synthesized by the precursor, $Ni_{0.5}Co_{0.2}Mn_{0.3}(OH)_2$, from the co-precipitation method and the morphologies of the primary particle of precursors were flake and needle-shape by controlling the precipitation parameters. Identical powder properties, such as particle size, tap density, chemical composition, were obtained by same process of lithiation and heat-treatment. The relation between electrochemical performances of $Li(Ni_{0.5}Co_{0.2}Mn_{0.3})O_2$ and the primary particle morphology of precursors was analyzed by SEM, XRD and EELS. In the $Li(Ni_{0.5}Co_{0.2}Mn_{0.3})O_2$ cathode from the needle-shape precursor, the primary particle size was smaller than that from flake-shape precursor and high Li concentration at grain edge comparing grain center. The cycle and rate performances of the cathode from needle-shape precursor shows superior to those from flake-shape precursor, which might be attributed to low charge-transfer resistance by impedance measurement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.724-729
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• 2010

We have proposed a new configuration on the cathode structure to improve a neutron yield without the application of external ion sources in an inertial electrostatic confinement (IEC) device. A neutron yield in the IEC device is closely related to the potential well structure generated inside the cathode and is proportional to the ion current. Therefore, the application of a double grid cathode structure to the IEC device is expected to produce a higher ion current and neutron yield than at a single grid cathode due to a high electric field strength generated around the cathode. These possibilities were verified as compared with the ion current calculated from both shape of the single and double grid cathode. Additionally from the results of ion's lives and trajectories examined at various outer cathode voltages and grid cathode configurations by using particle simulations, the validity of the double grid cathode was confirmed.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.367-370
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• 2002

CRTs can be improved by means of magnetic quadrupoles. Areas of improvement are convergence, spot shape, image-flatness and space charge compensation.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.69-76
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• 2011

PEMFC (polymer electrolyte membrane fuel cell) is device that generates electricity from hydrogen. It is one of the subjects related to renewable energy and various research has been conducted on the PEMFC. PEMFC has low operating temperature and high efficiency among fuel cells, and is given attention as means for automobile and domestic use. Analysis of flow field pattern in supplying hydrogen and oxygen is part of the research to increase PEMFC efficiency. In this study, separation plate currently used in PEMFC is transformed to wave shape and mass transfer characteristics in the channel is examined through numerical and experimental analysis. Wave shape separation plate yielded 18% increase of efficiency compared to separation plate used in normal channel. And improvements in mass transfer characteristics were verified.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.3
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• pp.1-5
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• 2000

This paper described about variance of optical and electrical characteristics on a fluorescent lamp according to tube shape by measuring electric field of positive column, temperature and luminance of tube w- all. Electric field calculation of several amps shows that the characteristics was not changed in positive column, though cathode fall length, and the values of temperature and luminance of tube wall, changes mush in cathode region.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.868-871
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• 2002

In this paper, we introduce an efficient three-dimensional magnetic field mapping system for a Deflection Yoke (DY) in Cathode-Ray Tube (CRT). A three-axis Hall probe mounted in a small cylindrical bar and three stepping motors placed in a nonmagnetic frame are utilized for the mapping. Prior to the mapping starts, the inner contour of DY is measured by a laser sensor to make a look-up table for inner shape of DY. Three-axis magnetic fields are then digitized by a three-dimensional Hall probe. The results of the mapping can be transformed to various output formats such as multipole harmonics of magnetic fields. Field shape in one, two and three-dimensional spaces can also be displayed. In this paper, we present the features of this mapping device and show some analysis results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.2
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• pp.26-32
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• 2010

This paper reports some experimental result in grinding and polishing of silicon cathodes used in semiconductor manufacturing process. Cup shape diamond core wheels were used in experiments and the radial and tangential grinding forces were measured with surface roughness. In polishing experiments, flat type and donut type wool polishing tools were tested. The experimental results indicate that the grinding forces are proportional to the material removal rates and the surface roughness are inversely proportional to the spindle speed. The surface roughness of polished Si decreases with polishing time and higher spindle speed.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.2
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• pp.231-238
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• 2006

The performance of free-breathing polymer electrolyte membrane fuel cell (PEMFC) was studied experimentally and the effect of cathode separator structure on the cell performance was investigated. Cathode separators were used for the cell with $18cm^2$ active area. In channel type, the contact resistance is low, and the nature convection. which is strongly affected by the cross-sectional shape of cathode separator channel, is dominant in a cell performance. The maximum power density with $18cm^2$ active area is $105mW/cm^2$ using the 10mm depth and 2mm width channel. A computational analysis was optimum structure of free-breathing channel type PEMFC for robotic application.

• Journal of the Korean institute of surface engineering
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• v.30 no.4
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• pp.239-247
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• 1997

The electrochemical machining of carbon steel was carried in various electrolytes which contain NACl and $NaCIO_3$. Though electrolyte containg NaCl yields fast machining rate, dimensional control is rather difficult. In the case of electrolyte with $NaCIO_3$, dimensional control of anode shape can be obtained through modification of cathode design. Mathematical modeling is also performed for these systems and agreements are good compared with experimental date. The constant gap experiment butween two electrode yielded faster machining rate than constant cathode moving rate experiment.

• Journal of the Korean Ceramic Society
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• v.53 no.4
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• pp.406-410
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• 2016

Carbon-coated sodium iron pyrophosphate ($Na_2FeP_2O_7$) was prepared by a simple and low-cost pyro-synthesis route for further use as the cathode for Na-ion batteries. The X-ray diffraction (XRD) pattern of the sample annealed at $650^{\circ}C$ confirmed the pure triclinic phase of $Na_2FeP_2O_7$. Electron microscopy studies revealed a cross linked plate shape morphology of the $Na_2FeP_2O_7$ sample. When tested for application in Na-ion battery, the $Na_2FeP_2O_7$ cathode showed two redox pairs in the potential window of 2.0-4.0 V. The cathode registered initial discharge and charge capacities of 80.85 and 90 mAh/g, respectively, with good cycling performance.