• 제목/요약/키워드: Low-Temperature

검색결과 17,506건 처리시간 0.044초

Low temperature deposition of carbon nanofilaments using vacuum-sublimated $Fe(CO)_5$ catalyst with thermal chemical vapor deposition

  • Kim, Nam-Seok;Kim, Kwang-Duk;Kim, Sung-Hoon
    • 한국결정성장학회지
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    • 제17권1호
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    • pp.18-22
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    • 2007
  • Carbon nanofilaments were deposited on silicon oxide substrate by thermal chemical vapor deposition method. We used $Fe(CO)_5$ as the catalyst for the carbon nanofilaments formation. Around $800^{\circ}C$ substrate temperature, the formation density of carbon nanofilaments could be enhanced by the vacuum sublimation technique of $Fe(CO)_5$, compared with the conventional spin coating technique. Finally, we could achieve the low temperature, as low as $350^{\circ}C$, formation of carbon nanofilaments using the sublimated Fe-complex nanograins with thermal chemical vapor deposition. Detailed morphologies and characteristics of the carbon nanofilaments were investigated. Based on these results, the role of the vacuum sublimation technique for the low temperature deposition of carbon nanofilaments was discussed.

가열수 온도에 의한 저온진공건조 열적 특성에 관한 연구 (A Study on the Thermal Characteristics of Low Temperature Vacuum Drying by Hot Water Temperature)

  • 김경근;최순열
    • Journal of Advanced Marine Engineering and Technology
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    • 제25권3호
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    • pp.588-594
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    • 2001
  • The aim of this paper is to develop the low temperature vacuum dryer, with low initial investments and operating costs, easy operating method and trouble-free operation Usally operations just below atmospheric pressure, as with direct dryers, but some are built for vacuum operation with pressure as low 50 mmHg abs. The lowers the boiling point to $39^{\circ}C$ The experimental data of quantitative analysis for using practically were obtained by the constant drying rate period and reducing drying rate period according to the temperature of hot water which is the experimental parameters of present experiment. As the results, it took about 20 hours for material to reach about 18% of the final moisture content is order to store products for a long time about 450% of the early moisture content at the beginning of drying and maximum drying rate comes to about 0.30 kg/m2hr at about 350% of the moisture content.

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저온환경에서 자착형 방수시트의 부착성능에 관한 연구 (A Research on Attachment Strength of Self-Adhesive Waterproofing Sheet in Low-Temperature Environment)

  • 안기원;박완구;허능회;김윤호;박진상;오상근
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2012년도 추계 학술논문 발표대회
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    • pp.27-28
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    • 2012
  • This study is to low-temperature in using self-adhesive waterproofing sheet. Using self-adhesive waterproofing sheet is very comfortable in a waterproofing construction site. However, when self-adhesive waterproofing sheet is constructed from a low-temperature environment, there has been a attachment strength shortage. Therefore, this study on the attachment strength of self-adhesive waterproofing sheet is to investigate the low-temperature in the environment.

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SUS304강의 사이클의존형에서 시간의존형균열성장으로의 천이에 관한 연구 (A Study on Transition From Cycle-dependent to Time-dependent Crack Growth in SUS304 Stainless Steel)

  • 주원식;조석수
    • Journal of Welding and Joining
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    • 제14권1호
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    • pp.38-46
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    • 1996
  • High temperature low cycle fatigue crack growth behavior is investigated over a range of two temperatures and various frequencies in SUS 304 stainless steel. It is found that low frequency and temperature can enhance time-dependent crack growth. With high temperature, low frequency and long crack length, ${\Delta}J_c/{\Delta}J_ f$, the ratio of creep J integral range to fatigue J integral range is increased and time-dependent crack growth is accelerated. Interaction between ${\Delta}J_f$ and ${\Delta}J_c$ is occured at high frequency and low temparature and ${\Delta}J_c$, creep J integral range is fracture mechanical parameter on transition from cycle-dependent to time dependent crack growth in creep temperature region.

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Low temperature-operating NiO-CoO butane gas sensors

  • 정동호;최순돈;민봉기
    • 센서학회지
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    • 제17권4호
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    • pp.303-307
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    • 2008
  • $NiO,\;Cu_2O,\;Mn_2O_3$ and $Cr_2O_3$ as p-type semiconductors were added in CoO with 15 wt.% ethylene glycol binder and measured the butane gas sensing characteristics. The highest sensitivity is obtained for the NiO-CoO sensors. CoO-20 at.% NiO sensor with 15 wt.% ethylene glycol binder sintered at $1100^{\circ}C$ for 24 h exhibits high sensitivity of 90 % to 5000 ppm butane gas at the sensor temperature of $250^{\circ}C$, compared to low sensitivities at the low operating temperature for commercial sensors. Response and recovery times are, respectively, within few seconds and 1min in the static flow system, indicating rapid adsorption and desorption of butane gas on sensor surface even at this low temperature.

Stability of Low Temperature a-Si:H TFT on Stainless Steel Substrate

  • Kim, Sung-Hwan;Kim, Sang-Soo;Park, Yong-In;Peak, Seung-Han;Lee, Kyoung-Mook;Park, Choon-Ho;Lim, Yu-Sok;Kim, Chang-Dong;Kang, In-Byeong
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.247-249
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    • 2008
  • Low Temperature a-Si:H TFT on stainless steel substrate has been developed for the flexible electrophoretic display. Stability of low temperature a-Si:H TFT is more important point than its initial device characteristics. Thus, we have studied device characteristics of low temperature a-Si:H TFT in terms of stability for driving electrophoretic display.

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염화물 및 아질산염을 사용한 저온환경하 모르타르내 철근의 부식특성 (Corrosion Behaviors of Rebar in Low Temperature Mortar with Chloride and Nitrite)

  • 박정훈;기경국
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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    • pp.218-219
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    • 2017
  • In order to examine the possibility of practical at low-temperature environment curable cement mortar with chloride and nitrite as cold resistance admixture for rebar corrosion prevention. As a result, chloride was used using nitrite complex in low temperature environment and corrosion performance of rebar was improved and mortar strength was promoted. The ratio of nitrite than chloride applied more than twice, corrosion of the reinforcing bars will not occur even in low temperature environment, cement hydration reaction will be promoted and mortar will prevent freezing damage.

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비병원성 Bacteriocin 생성 Pseudomonu solonueomm의 저온성 균주를 이용한 담배 세균성마름병 방제효과 (Biological Control Effect of Treating Avirulent Bacteriocin-Producing Strain of Pseudomonas sozanacearum Adapted to Low Temperature on Tobacco Bacterial Wilt)

  • 이영근;손준수
    • 한국연초학회지
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    • 제15권1호
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    • pp.26-33
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    • 1993
  • Effect of an avirulent bacteriocin-producing strain(ABPS) of Pseudomonas solanacearum adapted to low temperature on the control of tobacco bacterial wilt was examined under the natural field conditions. The ABPS of p. solanacearum were succeeding-cultured at gradually low temperature, 3$0^{\circ}C$ to 13$^{\circ}C$. The isolates adapted to low temperature grew faster than the wild type either in artificial media or on the tobacco rhizoplane. The control effect of one of the isolates on bacterial wilt was higher than that of the wild type when the bacterial suspension had been poured onto the tobacco rhizosphere soil on 1 day before and 15 days after transplanting to the field. It was suggested that ABPS of p. solanaceamm adapted to the low temperature, might be more effective biological control agent than the wild type.

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방동제와 경화촉진제를 사용한 저온환경하 모르타르의 초기압축강도에 관한 실험적 연구 (A Experimental Study on Early Age Compressive Strength of Cement Mortar Using Anti Freezer and Hardening Accelerator at low temperature)

  • 김목규;이한승
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2014년도 추계 학술논문 발표대회
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    • pp.135-136
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    • 2014
  • In this study, the experimental study on the early age compressive strength of cement mortar using anti freezer and hardening accelerator at low temperature was conducted. For this study, all of materials for experiment were kept in a low temperature for 24 hours before mortar mixing. After mortar curing at low temperature, compressive strength was measured at the early ages. Furthermore, properties of hardened cement material was analysed using TG-DTA and MIP.

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저온기 콘크리트의 조기압축강도 확보방안에 관한 연구 (A Study on Securing Early Strength of Concrete in a Low Temperature Time)

  • 이도범;최일호
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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    • pp.273-276
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    • 2004
  • Recently. cold weather constructions were popularized because of the importance of construction term. The special method about mix design and curing of concrete was being planned to conduct cold weather constructions, but these method were not considered in a low temperature time. A Strength revelation of concrete is delayed in a curing condition of low temperature. If a construction was loaded in this case, cracks or remaining deformations are generated in a construction. So, a strength revelation characteristic in early age was investigated to secure early strength of concrete in curing condition of a low temperature. In this study, the method about concrete mix design was presented to secure construction safety in a low temperature time.

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