• Carbon letters
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• v.16 no.1
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• pp.45-50
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• 2015

High crystallinity coke-based activated carbon (hc-AC) is prepared using a potassium hydroxide solution to adsorb carbon dioxide ($CO_2$). The $CO_2$ adsorption characteristics of the prepared hc-AC are investigated at different temperatures. The X-ray diffraction patterns indicate that pitch-based cokes prepared under high temperature and pressure have a high crystal structure. The textural properties of hc-AC indicate that it consists mainly of slit-like pores. Compared to other textural forms of AC that have higher pore volumes, this slit-pore-shaped hc-AC exhibits higher $CO_2$ adsorption due to the similar shape between its pores and $CO_2$ molecules. Additionally, in these high-crystallinity cokes, the main factor affecting $CO_2$ adsorption at lower temperature is the pore structure, whereas the presence of oxygen functional groups on the surface has a greater impact on $CO_2$ adsorption at higher temperature.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.319-321
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• 1998

Some design technologies of AC traction motor for rolling stocks are presented. AC Traction motors for rolling stocks are operated in worst conditions such as frequent mechanical vibrations, compact design with limited mounting space, severe thermal stress at outside, driven with nonsinusoidal voltage waveform inverters, and so on. Therefore, design procedures must be carefully investigated in the viewpoint of theoritically and practical use. Design procedure contains, the motor size determination, electromagnetic circuit design, insulation system design, vibrations and thermal expansion of rotor bars, temperature rise, as well as output characteristics.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.335-342
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• 2015

This research was conducted to examine the changes in growth and production of Oryza sativa L. cv. Ilmi, which was developed to cultivate high yielding rice variety in the Southern plains of Korea. The seedlings of the rice were cultivated from May to October in 2012 under three different conditions: control, AC-AT, ambient $CO_2$ + ambient temperature; AC-ET, ambient $CO_2$ + elevated temperature; EC-ET, elevated $CO_2$ + elevated temperature. The aboveground biomass, belowground biomass, the total biomass of the rice, and panicle weight per individual were the heaviest in the EC-ET. But, the number of grains per panicle and the weight of one grain was higher at the condition of AC-ET and EC-ET than that of AC-AT. The number of tiller was higher at the condition of AC-AT and AC-ET than that of EC-ET. However, there was no significant difference in the number of panicles per individual and the ripened grain rate among the control and global warming treatments. Crop yield was the highest in the EC-ET. This result means that the global warming condition should be considered in the selection of suitable paddy field for the limibyeo in the future.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.1
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• pp.68-76
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• 2014

The present study has evaluated the $CO_2$ adsorption amount of activated carbon pellets (AC). Coconut shell based test AC were modified with surface impregnation of glycine, glycine metal salts and monoethanolamine for low level $CO_2$ (3000 ppm) adsorption. Physical and chemical properties of prepared adsorbents were analyzed and the adsorbed amount of $CO_2$ was investigated by using pure and 3,000 ppm $CO_2$ levels. The impregnation of nitrogen functionalities was verified by XPS analysis. The adsorption capacity for pure $CO_2$ gas was found to reach upto 3.08 mmol/g by AC-LiG (Activated carbon-Lithium glycinate), which has the largest specific surface area ($1026.9m^2/g$). As for low level $CO_2$ flow the primary amine impregnated adsorbent showed 0.26 mmol/g of adsorption amount, indicating the highest selectivity. An adsorbent with potassium-glycine salts (AC-KG, Activated carbon-Potassium glycinate) instead of amine presented with 0.12 mmol/g of adsorption capacity, which was higher than that of raw activated carbon granules (0.016 mmol/g).

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.35-45
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• 2006

Cobalt catalysts for gas mask loaded on various supports such as $Al_{2}O_{3},\;TiO_{2}$, AC(activated carbon) and $SiO_{2}$ were used to examine influences of calcination temperatures and reaction temperatures for CO oxidation. $Co(NO_{3})_2{\cdot}6H_{2}O$ was used as cobalt precursor and the catalysts were prepared by incipient wetness impregnation. The catalysts were characterized using XRD, TGA/DTA, TEM, $N_{2}$ sorption, and XPS. For the catalytic activity, support was in the order of ${\gamma}-Al_{2}O_{3}>TiO_{2}>SiO_{2}>AC\;and\;Al_{2}O_{3}$. The catalytic activity at lower temperature than $80^{\circ}C$ showed that with the increase of reaction temperature, cobalt catalysts on ${\gamma}-Al_{2}O_{3},\;TiO_{2},\;AC\$ has the negative activation energy but that of $SiO_{2}$ was positive.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.663-667
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• 1998

This paper describes for reducing harmonic distortion on CO2 welding machine with nonlinear load characteristic using single-switch three-phase AC/DC converter. The low-order harmonic component amplitude of the phase current of single-switch three-phase discontinuous mode is calculated. Experimental results show that CO2 welding machine with single-switch three-phase AC/DC converter is effectively controlled with power factor correction for phase current during welding time.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.155-156
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• 1996

The intercommissural(AC-PC) line is automatically detected for HR and PET images. With the detected AC-PC lines from MR and PET images, fully non-iterative automatic co- registration is accomplished. It provides a new automated method for image co-registration.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.484-488
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• 2001

The grid voltage of commercial utility power source hi Japan and USA is 100rms, but in China and European countries, it is 200rms. In recent years, In Japan 200Vrms out putted single phase three wire system begins to be used for high power applications. In 100Vrms utility AC power applications and systems, an active voltage clamped quasi-resonant Inverter circuit topology using IGBTs has been effectively used so far for the consumer microwave oven. In this paper, presented is a half bridge type voltage-clamped high-frequency Inverter type AC-DC converter using which is designed for consumer magnetron drive used as the consumer microwave oven in 200V utility AC power system. This zero voltage soft switching Inverter can use the same power rated switching semiconductor devices and three-winding high frequency transformer as those of the active voltage clamped quasi-resonant Inverter using the IGBTs that has already been used for 100V utility AC power source. The operating performances of the voltage source single ended push pull type Inverter are evaluated and discussed for consumer microwave oven. The harmonic line current components In the utility AC power side of the AC-DC power converter operating at ZVS­PWM strategy reduced and improved on the basis of sine wave like pulse frequency modulation and sine wave like pulse width modulation for the utility AC voltage source.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.401-406
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• 2003

New planar discharge structured AC-PDP has been developed by using TFCS (Thick Film Ceramic Sheet) technology. By applying TFCS to AC-PDP, a sustaining electrode and scanning electrodes are embedded in the TFCS. It is shown that panel performances such as electrical and optical characteristics are superior to commercialized coplanar AC-PDP as well as cost reduction. Moreover the experimental result shows panel performances can be improved drastically by continuous development.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.185-186
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• 2000

For the quantitative investigation of the erosion of MgO layers in real ac-PDP cells, we constructed a microscopic spectrophotometer which is capable of measuring transmission spectra from the area as small as 20 ${\times}$ 20 ${\mu}m^2$. In the test on the sputtered MgO films with a thickness gradient, we were able to probe the thickness variation of 1000 nm over $1000-{\mu}m$ distance. Using this instrument, we were able to determine not only the erosion rate at the particular position of ac-PDP cells but also the relative erosion rate at different positions in a single ac-PDP cell.