• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.678-680
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• 2002

Vertically aligned carbon nanotubes(CNTs) have been grown on Ni-coated TiN/Si substrate by microwave plasma chemical vapor deposition using $H_2/CH_4$ mixture gas. We have investigated the Effect of process parameters on the growth of CNT. During the growth, microwave power, pressure, and growth temperature were varied from 300 W to 700 W, 10 Torr to 30 Torr, and 300 $^{\circ}C$ to 700 $^{\circ}C$. respectively. Then we controlled the size of CNTs. The structure of CNT was sensitively dependent on the process parameters.

• Journal of the Korean institute of surface engineering
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• v.46 no.2
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• pp.55-60
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• 2013

Superhard TiN coatings were fabricated by DC and ICP (inductively coupled plasma) assisted magnetron sputtering techniques. The effect of ICP power, ranging from 0 to 300 W, on coating microstructure, preferred orientation mechanical properties were systematically investigated with HR-XRD, SEM, AFM and nanoindentation. The results show that ICP power has a significant influence on coating microstructure and mechanical properties of TiN coatings. With the increasing of ICP power, coating microstructure evolves from the columnar structure of DC process to a highly dense one. Grain sizes of TiN coatings were decreased from 12.6 nm to 8.7 nm with increase of ICP power. The maximum nanohardness of 67.6 GPa was obtained for the coatings deposited at ICP power of 300 W. Preferred orientation in TiN coatings also vary with ICP power, exerting an effective influence on film nanohardness.

• Korean Journal of Materials Research
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• v.14 no.4
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• pp.300-306
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• 2004

A laser welding has been made between sintered tip of Fe-Co-W and low carbon steel shank for the diamond saw blade. The welding characteristics and formation of defect has been investigated carefully for the weld fusion zone in different welding condition. Full penetration has been observed for the whole range of heat input investigated in the present work. Bead width and under-fill have been increased with the increase of heat input. With increasing of heat input small cavities were decreased while large cavities were increased. The ratio of total cavity area to the entire weld bead area was not changed significantly with change of heat input. Most of cavities were found near the tip, and supposed to be formed from the pore in the tip.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.129-133
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• 2005

대기압 글로우 플라즈마를 이용하여 반도체 리드프레임(Alloy 42) 도금 전처리 습식 공정을 건식으로 대체하였다. 13.56 MHz의 RF 전원을 사용하여 300 W 파워에서 안정적인 대기압 글로우 플라즈마를 발생시켰으며, 금속 리드프레임에 플라즈마가 직접 접촉해도 아크나 스트리머 발생이 없었다. 플라즈마 소스 가스로는 알곤(Ar)을 사용하였으며, 활성가스로 산소($O_2$)를 첨가하였다. 300 W 파워에서 산소를 50 sccm 공급하고 100 mm/sec 속도로 리드프레임을 처리한 결과, 처리 전 접촉각이 $82^{\circ}$에서 처리 후 $10^{\circ}$ 이하로 낮아졌다. 플라즈마 처리 후 리드프레임 표면 거칠기 변화를 AFM으로 측정하였다.

• JOURNAL OF ELECTRICAL WORLD
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• s.335
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• pp.22-27
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• 2004

Microturbine geneator is the system generating electric power under 300kW using a gas turbine, and the combined heat and power generating system is recycling exhausted gas to increase thermal efficiency. Microturbine system is featured as small, efficient

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.397-405
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• 2009

Nowadays, power supplies for LCD TV of larger and slimmer screen size are required to have high power density and high efficient characteristics. In order to meet these requirements, Multi-phase interleaved LLC resonant converter is applied for increasing power density and reducing the current rating in the used devices. In this paper, gain characteristics and the experimental results of the proposed two-phase LLC resonant converter which implemented by the simple control circuit are verified based on the theoretical analysis and the 300W experimental prototype.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.406-414
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• 2009

To cope with the high power density and low cost in switching power supply, LLC resonant converters with the two resonant tank circuits composed of resonance capacitors and two transformers are proposed in this paper. Each transformers used for the proposed resonant circuits are parallel connected in the primary and series connected in the secondary to reduce the current unbalance. The proposed LLC resonant converters are described and verified on 300W experimental prototype.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.923-924
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• 2007

due to the modification of ventilation system for variable speed high efficiency PMSM, the ventilation structure is analyzed in this part. First, a cooling structure was proposed for the variable speed PMSM. Through the contrast result of whole stress and speed distribution in the cooling channel by fluid field, the fans setting fashion is confirmed. By the studying of cooling structure for improved PMSM, the position of the cooling hole in the rotor is optimized by the finite element method. At last, the thermal field distribution of the motor is calculated by FEM. The calculated thermal rise is in accord with measured value, which provides effective basement for the design and safety operation of PMSM.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.219-223
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• 1981

Experiments on methane gas digestion were conducted to prevent livestock pollution and develop substitute energy. When about 30(w/w)% of sludge was added to cow feces, pig feces, and poultry feces and digested at 37$^{\circ}C$ for 20 days, methane gas produced per Kg of organic matter for cow feces, pig feces, poultry feces was 131, 248 and 235 l, respectively. pH decreased slightly at first but increased gradually afterwards during digestion period. When 20, 30, and 40(w/w)% of sludge were added to the mixture of cow feces (300g) and water (200g), the volumes of gas produced were 6.1, 14.5 and 13.4 l, respectively. Volume of methane gas produced from the mixture of cow feces and saw dust was much more than that from the mixture of cow feces and rice polishings. The contents of N, K, P for digestion residues were sufficient to be utilized as a fertilizer. When methane gas digestion was carried out with cow feces in a submersible pump digester the volume of methane gas produced per Kg of organic matter was 188 l. The price of total methane gas produced at this digestion was similar to that of the electric power consumed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.6
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• pp.297-303
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• 2003

Mn-Ni-Co type thin films were prepared at various conditions by a rf magnetron sputtering system. At the condition. or substrate temperature of $300^{\circ}C$ and $Ar/O_2$= 10/0, a cubic spinel phase was obtained. When oxygen was included in process gas, a cubic spinel phase was not formed even after the thermal annealing at $900^{\circ}C$. The thermistor thin film had no other elements except Mn, Ni and Co. The infrared reflection spectra of the thermistor thin films showed that the films had somewhat high reflectance for incoming infrared ray with some angle. The etch rate of the thermistor thin films was about 63nm/min at a condition of DI water : $HNO_3$: HCl = 60 : 30 : 10 vol%. The B constant and temperature coefficient of resistance of the thermistor thin films were 3500 K and -3.95 %/K, respectively. The voltage responsivity of the thermistor thin film infrared sensor was 108.5 V/W and its noise equivalent power and specific detectivity were $5.1\times 10^{-7}$ W/$Hz^{-1/2}$ and $0.2\times 10^6$cm $Hz^{1/2}$/W, respectively.