• 한국세라믹학회지
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• 제29권9호
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• pp.750-756
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• 1992

Reaction bonded si-SiC composites were prepared by silicon infiltration technique at temperature of 1$600^{\circ}C$ for 30 minutes in vaccum atmosphere. The microstructure and mechanical properties of Si-SiC composites were investigated and characterized. UF-15 and SE-10 as SiC powders, phenolic resin and carbon black as carbon source, and metallic silicon powder as molten Si source were used as starting materials. New SiC crystallines nucleatd and grown by reaction of Si and C were detected by TEM and SEM-EDS. The bonding between new and original SiC was found to be strong. But the wetting of SiC by unreacted metallic Si and the rapid grain growth of new SiC decreased density and fracture toughness. Fracture toughness and modulus of rupture of Si-SiC composite were about 3.2 MPa.m1/2 and 480 MPa, respectively.

• 한국세라믹학회지
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• 제34권5호
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• pp.544-551
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• 1997

We tried to improve the coating capability of the coating material using an additive(hexagonal cystalline graphite) of 2%, 3%, 4% and 6% under various pouring temperature for the easy isolation of sand and coating material from the final product. As a result in case of using a 2% and 3% additive generally no burning state has been occurred under the low pouring temperature, but it has been gradually increased with the pouring temperature. On the other hand in case of using a 4% and 6% additive there has been no burning state through out the whole pouring temperature. From this result we could see that the best state of the final product without sand and coating material could generally be obtained if 4% and/or 6% of the crystalline graphite and the pouring temperature of 140$0^{\circ}C$$\pm$5$^{\circ}C$ would be used.

• 동력기계공학회지
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• 제15권6호
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• pp.16-21
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• 2011

Over the past years, many research works have been carried out to investigate the factors which govern the performance of diesel engine. The air pollutant emission from the diesel engine is still a significant environmental concern in many countries. In the present study, new system of smoke filtration of diesel engine is proposed. This new system is using vacuum equipment and filter for capture smoke. To verification new system experiments are performed at diesel vehicle and engine dynamometer. As a result it is founded that smoke is decreased of 67% at vehicle test and decrease of 45.2% at full load condition of engine dynamometer test.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.84-89
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• 1992

The polycrystalline $CuInS_2$ thin films are prepared by vacuum heat treatment of layer, which is deposited by vaccum evaporation in order. The electrical and optical properties of the films are investigated at various sulfur deposition mole rate, substrate temperature, heat treatment temperature and time. From data, n type-$CuInS_2$ exhibits resistivity, transmittance and energy band gap with 142[${\Omega}{\cdot}cm$], 73[%], and 1.5[eV] respectively at optimum fabrication condition. Finally, the films are fabricated with chalcoprite structure.

• 대한기계학회논문집
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• 제17권7호
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• pp.1751-1760
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• 1993

The squeeze casting process is considered as an attractive way to form the primary product of near net shape metal matrix composites for wide use in automobile industry. To understand for infiltration limit in squeeze casting processes, the SAFFIL short fiber preform of volume fraction $10%{\sim}23%$ were fabricated by vaccum pumping and speed control press, and the optimal condition for fiber preform fabrication had been experimentally obtained. The composite materials were fabricated by forced infiltration of molten metals such as Al6061, Al7075, pure Al, AC8A, and Al2024. The infiltration distance and deformation of fiber preform are observed, and tensile strength were measured from at the room temperature.

• Journal of Advanced Marine Engineering and Technology
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• 제34권6호
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• pp.833-839
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• 2010

오랫동안 디젤엔진의 성능에 지배적인 요인에 대하여 많은 연구들이 있었으며 디젤엔진의 오염 문제는 아직도 중요한 환경문제이다. 본 연구에서는 디젤엔진의 매연저감장치에 대한 새로운 제안을 한다. 새로운 제안은 진공압을 이용하여 매연을 포집한다. 새로운 제안을 확인하기 위해 엔진 다이나모시험을 수행하였다. 그 결과 매연을 줄일 수 있었다.

• 대한화학회지
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• 제19권6호
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• pp.420-422
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• 1975

백금 백금-텅스텐 증착막에 의한 수소, 일산화탄소의 화학흡착과 화학흡착시킨 산소의 수소 titration을 $110^{\circ}$C에서 실험해본 결과, $H_2/O_2$ titration 방법에 의한 백금-텅스텐 증착막에서의 백금 표면적 측정이 가능한 것 같다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.770-772
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• 2002

A new dry-processing method of organic gate dielectric film in field-effect transistors (FETs) was proposed. The method use vapor deposition polymerization (VDP) that is continuous and low temperature process. It has the advantages of shadow mask patterning and dry processing in flexible low-cost large area applications. Here, 80 nm-thick Al as a gate electrode was evaporated through shadow mask. Gate insulators used two different polyimides. The one material was 4,4'-oxydiphtahlic anhydride (ODPA) and 4,4'-oxydianiline (ODA). Another was 2,2-bis(3,4-dicarboxyphenyl) Hexafluoropropane Dianhydride (6FDA) and 4,4' -oxydianiline (ODA). These were co-deposited by high-vaccum thermal-evapora and cured at 150 $^{\circ}C$ for 1 hour, respectively. Pentacene as a semiconductor and 100 nm-thick Au as a source and drain electrode were evaporated through shadow mask.

• 한국진공학회지
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• 제1권1호
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• pp.153-161
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• 1992

A plasma has been used in a high vaccum, cold wall reactor for low temperature deposition of C54 TiSi2 and for in-situ surface cleaning prior to silicide deposition. SiH4 and TiCl4 were used as the silicon and titanium sources, respectively. The deposited films had low resistivities in the range of 15~25 uohm-cm. The investigation of the experimental variables' effects on the growth of silicide and its concomitant silicon consumption revealed that and were the dominant species for silicide formation and the primary factors in silicon consumption were gas composition ratio and temperature. Increasing silane flow rate from 6 to 9 sccm decreased silicon consumption from 1500 A/min to less than 30 A/min. Furthermore, decreasing the temperature from 650 to $590^{\circ}C$ achieved blanket silicide deposition with no silicon consumption. A kinetic model of silicon consumption is proposed to understand the fundamental mechanism responsible for the dependence of silicon consumption on SiH4 flow rate.

• 한국자동차공학회논문집
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• 제2권4호
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• pp.100-111
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• 1994

Observations on the near-nozzle behavior of an unsteady fuel spray through single cylindrical hole nozzle were made by phase Doopler anemometer and microphotographs. At the edge of the spray, droplet velocity peaked during needle opening and closing. Droplet sizes tended to be small on the edge of spray. The near-nozzle spray angle taken from the microphotographs was time-dependent, even though it increased with gas-to-liquid density ratio as expected. The near-nozzle spray angle was the greatest on the initial stage and decreased to a relatively constant value after about one third of the total injection duration regardless of the ambient gas conditions, even in the near-vaccum condition. The wider near-nozzle spray angle in the early stage is due to the flow characteristics inside the nozzle rather than aerodynamic interactions. However, once the spray was established, aerodynamic interactions are essential in the near-nozzle atomization.