• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.54 no.10
• /
• pp.465-470
• /
• 2005

In this paper. an experimental study, for method of increasing the efficiency of electrostatic precipitator for the collection of submicron-sized particles has been studied. All AC electric field was used to induce agglomeration of bipolory charged Particles. .4 bipolar AC-agglomeration system. consisted with a multineedle-mesh discharge system with a control grid, was proposed and investigated. Systematic experiments were carried out to investigate the agglomeration ratio of the AC-agglomeration system as a function of the different grid spacings and grid resistances for the submicron particles generated from liquid prorhane gas burning. The agglomeration ratios, which indicate the particle numbers before and after agglomeration of the test particles in number concentration base, were found to be 0.87, 1.80, 3.86, 9.50 and, 11.00 times for the particle sizes of 0.3. 0.5, 0.7, 1.0, and 2.0$\mu$m at applied voltage of 3.5kV, respectively which showed that the fine particle numbers were decreased while the larger particle numbers were increase greatly.

• Transactions of the Korean hydrogen and new energy society
• /
• v.23 no.5
• /
• pp.448-454
• /
• 2012

In this paper, a three-dimensional hydrogen absorption model is applied to a thin double-layered annulus ZrCo hydride bed and validated against the temperature evolution data measured by Kang et al. The present model reasonably captures the bed temperature evolution behavior and the 99% hydrogen charging time. The equilibrium pressure expression for hydrogen absorption on ZrCo is derived as a function of temperature and the H/M atomic ratio based on the pressure-composition isotherm data given by Konishi et al. In addition, this present model provides multi-dimensional contours such as temperature and H/M atomic ratio in the thin doublelayered annulus metal hydride region. This numerical study provides fundamental understanding during hydrogen absorption process and indicates that efficient design of the metal hydride bed is critical to achieve rapid hydrogen charging performance. The present three-dimensional hydrogen absorption model is a useful tool for the optimization of bed design and operating conditions.

• Journal of Biosystems Engineering
• /
• v.29 no.1
• /
• pp.21-28
• /
• 2004

Spraying is one of the most efficient methods for pesticide and insecticide control. Generally, orchard sprayers(aircarrier sprayer) are used for such applications. However, when an orchard sprayer is used, only 20% of total amount of spray deposits on the target. The rest of spray are not only wasted but are also potential sources of environmental pollution. The research far the development of electrostatic spraying system for orchard sprayer was conducted to develop the new pesticide application technology for the reduction of environmental pollution and f3r the production of safe agricultural products. The spray characteristics for nozzles with the different charging methods were tested and the effect of electrostatic charge was analyzed, in the laboratory experiments. The results of this study indicate that the capacitive type of electrostatic spraying nozzle exhibits a large current deposition of water sprays on the sample target. The covering area ratio by conventional spraying system was 10.2%, while that of electrostatic sprays with pulse induction charging method gave the increased covering area ratio by 4.3 times.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.352-356
• /
• 2006

As a basic study to develop heating panel, the purpose of this study was to know possibility as a floor heating panel. We investigated working conditions and performance of pulsating heat pipe. Tests were conducted under the next conditions; Working fluid were R-22 and R-134a, charging ratio 40% and 50%, temperature of inlet water $60^{\circ}C$ and $70^{\circ}C$, flow rates $1{\sim}3kg/min$. The experimental results indicate that the pulsating heat pipe charged 50% showed better performance than 40%, R-22 is more suited to the working fluid than R-134a, and it has a possibility which can be applied to floor heating panel using a pulsating heat pipe.

• Tribology and Lubricants
• /
• v.34 no.6
• /
• pp.284-291
• /
• 2018

Ball-milling for reactant powders in advance and using an induction heating system for Ni-Al intermetallic coating process are known to enhance the reactivity of combustion synthesis. In this work, the effects of the charging weight ratio of ball to powder in ball-milling for reactant Ni-Al powders and the synthesizing temperature in induction heating on sliding wear behavior of the coating layers are investigated. Sliding wear behavior of the coating layers is examined against a tool steel using a pin-on-disc type sliding wear machine. As results, wear of the coating layer ball-milled without ball was severely worn out at the sliding speed of 2m/s, regardless of the synthesizing temperature in induction heating. However, the wear rate of the coating layers at the sliding speed was remarkably decreased with increasing the charging weight ratio of ball in ball-milling for reactant powders. This can be explained by the fact that the void in the coating layer is disappeared and the coating layer is densified by the ball-milling. The evidence showed that pitting damages were disappeared on the worn surface of ball-milled coating layer. Consequentially, the Ni-Al intermetallic coating layer could have better wear resistance at all sliding speed ranges with the ball-milling for reactant powders in advance.

• Journal of Power Electronics
• /
• v.15 no.6
• /
• pp.1438-1445
• /
• 2015

A new DC-DC power converter is researched for renewable energy and battery hybrid power supplies systems in this paper. At the charging mode, a renewable energy source provides energy to charge a battery via the proposed converter. The operating principle of the proposed converter is the same as the conventional DC-DC buck converter. At the discharging mode, the battery releases its energy to the DC bus via the proposed converter. The proposed converter is a non-isolated high step-up DC-DC converter. The coupled-inductor technique is used to achieve a high step-up voltage gain by adjusting the turns ratio. Moreover, the leakage-inductor energies of the primary and secondary windings can be recycled. Thus, the conversion efficiency can be improved. Therefore, only one power converter is utilized at the charging or discharging modes. Finally, a prototype circuit is implemented to verify the performance of the proposed converter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.11a
• /
• pp.137-140
• /
• 1998

An active-matrix LCD using thin film transistors (TFT) has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate si후미 distortion and pixel charging capability. which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the gate, data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the resistivity of gate line material on the pixel operations can be effectively analyzed. The gate signal delay, pixel charging ratio and level-shift of the pixel voltage were simulated with varying the parameters. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

• Progress in Superconductivity and Cryogenics
• /
• v.3 no.2
• /
• pp.49-54
• /
• 2001

The purpose of this study is to analyze the characteristics of the linear compressor for Stirling refrigerator. To ensure high performance and long life of the FPFD(Free Piston. Free Displacer) type Stirling refrigerator, the operating parameters of the linear compressor should be optimized. The experimental results show that the operating frequency of the linear compressor has significant effect on the input power characteristics. and that the compressor with higher charging pressure of working fluid has high pressure ratio. For the high performance of the linear compressor. compressor should be operated at the resonance frequency with respect to the given charging pressure.

• 한국전산유체공학회:학술대회논문집
• /
• 2011.05a
• /
• pp.135-140
• /
• 2011

The battery pack, a main component of NEV(Neighborhood Electric Vehicle), needs cooling system when it is charging or discharging to prevent the degradation of the battery charging efficiency. The purpose of this study is to analyse the effects of cooling methods, changing positions of inlet and outlet and changing area ratios of inlet and outlet. It has been observed that in the point of uniform cooling suction from the exit side is more efficient than blowing from the inlet. And there is a suitable inlet/outlet area ratio in maximizing the mass flow rate. The numerical analyse using a commercial code STAR-CCM+ version 4.02 were used for the study.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.264-266
• /
• 2001

We must consider resistance capacitance and their circuit connection condition for cable charging current test by IEC60265-1. According to their values and circuits, the ratio of applied voltage and transient recovery voltage are much different. This paper is convinced of TRV waves and proposes the optical circuit required at the standard via the simulation of all circuit conditions.