• 전기화학회지
• /
• 제16권4호
• /
• pp.191-197
• /
• 2013

리튬2차전지용 양극소재인 $Li(Ni_{0.5}Co_{0.2}Mn_{0.3})O_2$를 공침법을 이용해 $Ni_{0.5}Co_{0.2}Mn_{0.3}(OH)_2$ 전구체로부터 합성하였고, 공침조건을 조절하여 전구체의 1차 입자 형상을 Flake형상과 Needle형상으로 제어하였다. 동일한 공정으로 리튬과 혼합하고 열처리하여, 입도, 탭밀도, 화학적 성분 등이 동일한 분체물성의 양극 소재를 합성하였다. 전구체의 1차입자 형상에 따른 $Li(Ni_{0.5}Co_{0.2}Mn_{0.3})O_2$의 전기화학적 특성을 평가하고, 이 특성의 변화를 SEM, XRD, EELS로 이용하여 분석하여 연관성을 고찰하였다. Needle형상 전구체로 합성한 $Li(Ni_{0.5}Co_{0.2}Mn_{0.3})O_2$ 양극의 1차입자는 Flake형상 전구체로 합성한 경우보다 작고, EELS결과로는 입자표면의 Li농도가 내부보다 상대적으로 높았다. 전기화학적인 수명과 출력특성에서 Needle형상 전구체로 합성한 양극이 Flake형상 전구체의 경우보다 우수한 특성을 보였는데, 임피던스 측정으로부터 낮은 전하이동저항에 연관되어 있을 것으로 생각된다.

• 한국전기전자재료학회논문지
• /
• 제23권9호
• /
• pp.724-729
• /
• 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
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.367-370
• /
• 2002

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

• 한국수소및신에너지학회논문집
• /
• 제22권1호
• /
• pp.69-76
• /
• 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.

• 조명전기설비학회논문지
• /
• 제14권3호
• /
• pp.1-5
• /
• 2000

본 논문은 양광주의 전계, 관벅온도, 관벽휘도를 측정하여 관의 형태에 따른 형광램프의 광학적, 전기적 특성 변화를 측정한 것이다. 각 램프의 전계 계산 결과, 그 지수들은 양광주부분에서 거의 변화되지 않았지만 음극 강하의 길이는 크게 변화하였으며, 관벽온도와 휘도는 음극부분에서 크게 변화되었다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.868-871
• /
• 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.

• 한국기계가공학회지
• /
• 제9권2호
• /
• pp.26-32
• /
• 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
• /
• 제30권2호
• /
• pp.231-238
• /
• 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.

• 한국표면공학회지
• /
• 제30권4호
• /
• pp.239-247
• /
• 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.

• 한국세라믹학회지
• /
• 제53권4호
• /
• pp.406-410
• /
• 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.