• 제목/요약/키워드: 막저항

검색결과 853건 처리시간 0.023초

Properties of Al-doped ZnO Transparent Conducting Oxide Films Deposited with Ar Flow Rate by RF Magnetron Sputtering (RF 마그네트론 스퍼터링법으로 증착된 Al 도핑된 ZnO 투명 전도 산화막의 Ar 유량에 따른 특성)

  • Yi, I.H.;Kim, D.K.;Kim, H.B.
    • Journal of the Korean Vacuum Society
    • /
    • 제19권3호
    • /
    • pp.206-210
    • /
    • 2010
  • Al-doped ZnO thin films were deposited with various Ar flow rate by RF magnetron sputtering, and theire properties were studied. A high-quality thin film was obtained by controlling the Ar flow rate, and the influence of the Ar flow rate on the Al-doped ZnO thin film was confirmed. In all Al-doped ZnO thin films, light transmittance had above 80%. Through Hall measurement and X-ray photoelectron spectrometer, the sample of 60 sccm, which had the lowest resistivity, showed the lower Al concentration. This result was attributed to oxygen vacancy rather than Al concentration.

A study on the highly sensitive metal nanowire sensor for detecting hydrogen (수소감지를 위한 고감도의 금속 나노선 센서에 관한 연구)

  • An, Ho-Myoung;Seo, Young-Ho;Yang, Won-Jae;Kim, Byungcheul
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • 제18권9호
    • /
    • pp.2197-2202
    • /
    • 2014
  • In this paper, we report on an investigation of highly sensitive sensing performance of a hydrogen sensor composed of palladium (Pd) nanowires. The Pd nanowires have been grown by electrodeposition into nanochannels and liberated from the anodic aluminum oxide (AAO) template by dissolving in an aqueous solution of NaOH. A combination of photo-lithography, electron beam lithography and a lift-off process has been utilized to fabricate the sensor using the Pd nanowire. The hydrogen concentrations for 2% and 0.1% were obtained from the sensitivities (${\Delta}R/R$) for 1.92% and 0.18%, respectively. The resistance of the Pd nanowires depends on absorption and desorption of hydrogen. Therefore, we expect that the Pd nanowires can be applicable for detecting highly sensitive hydrogen gas at room temperature.

A study on Synthesis and Radiation Detector Fabrication of Thin Films by MW Plasma CVD (MWPECVD에 의한 박막의 합성과 방사선 검출 특성에 관한 연구)

  • Koo, Hyo-Geun;Lee, Duck-Kyu;Song, Jae-Heung;Noh, Kyung-Suk;Park, Sang-Hyun
    • Journal of radiological science and technology
    • /
    • 제27권2호
    • /
    • pp.45-50
    • /
    • 2004
  • Synthesis diamond films have been deposited on the molybdenum substrates using an microwave plasma enhanced chemical vapor deposition method. The effects of deposition time, surface morphology, infrared transmittance and Raman scattering have been studied. Diamond deposited on molybdenum substrate for 100 hours by MW plasma CVD from $CH_4-H_2-O_2$ gas mixture had good crystallity with $100[{\mu}m]$ thickness needed for radiation detector. Diamond radiation detector of M-I-M type was made and the current of radiation detector was increased by increasing X-ray dose.

  • PDF

Biofilm Formation of Food-borne Pathogens under Stresses of Food Preservation (식품 보존 스트레스에서의 식중독세균의 생체막 생성)

  • Lee, No-A;Noh, Bong-Soo;Park, Jong-Hyun
    • Korean Journal of Food Science and Technology
    • /
    • 제38권1호
    • /
    • pp.135-139
    • /
    • 2006
  • Most bacteria form biofilm as self-defence system, making efficient food sanitization, preservation, and instrument washing more difficult. Biofilm formation of Salmonella, E. coli, B. cereus, and S. aureus was observed during 24 hr food preservations by performing microtiter plate and glass wool assays. Most cells formed biofilm and attached onto glass wool. When biofilm formation and injury were analyzed on the microtiter plate, 10 and 20% acid-injured E. coli and S. aureus, respectively, 30-50% cold temperature $(4^{\circ}C)-injured$ B. cereus and E. coli, and 30-55% 6% sodium chloride solution-injured Salmonella showed significant biofilm formation. Results indicate biofilm formation level differed within species depending on type of stress.

Stable Desalination of Hardness Substances through Charge Control in a Capacitive Deionization System (축전식 탈염 시스템에서 전하량 제어를 통한 경도물질의 안정적인 탈염)

  • Kim, Yoon-Tae;Choi, Jae-Hwan
    • Applied Chemistry for Engineering
    • /
    • 제30권4호
    • /
    • pp.472-478
    • /
    • 2019
  • A stable desalination method of the hardness substance such as $Ca^{2+}$ by controlling the total charge (TC) supplied to the membrane capacitive deionization (MCDI) cell was studied. The adsorption (1.5 V) and desorption (0.0 V) were repeated 30 times while varying the TC in the adsorption process. The concentration and pH of effluent, adsorption and desorption amounts, current densities and cell potentials were analyzed in the desalination process. The maximum allowable charge (MAC) of the carbon electrode used in MCDI cell was measured to be 46 C/g. As a result of operation at TC (40 C/g) below the MAC value, electrode reactions did not occur, resulted in the stable desalination characteristics for a long-term operation. When operating at TCs (50, 60 C/g) above the MAC value, however, the concentration and pH of effluent varied greatly. Also, the scale was formed on the electrode surface due to electrode reactions, and the electric resistance of the cell gradually increased. It was thus concluded that it is possible to remove stably the hardness substance without any electrode reactions by controlling the charge supplied to MCDI cell during the adsorption process.

Optimization of Ar Reshape Process for 4H-SiC Trench MOSFET (4H-SiC Trench MOSFET 응용을 위한 Ar Reshape 공정 최적화)

  • Sung, Min-Je;Kang, Min-Jae;Kim, Hong-Ki;Kim, Seong-jun;Lee, Jung-Yoon;Lee, Wonbeom;Lee, Nam-suk;Shin, Hoon-Kyu
    • Journal of IKEEE
    • /
    • 제22권4호
    • /
    • pp.1234-1237
    • /
    • 2018
  • For 4H-SiC trench MOSFET which can reduce on-resistance and switching losses compared to 4H-SiC planar MOSFET, the optimization study for decrease of sub-trench was carried out. In order to decrease sub-trench, Ar reshape process was used and trench shapes were observed as a function of temperature and process time. As a result, it was confirmed that the process conditions for $1500^{\circ}C$ and 20 min were most effective for the suitable trench profiles. In addition, dry/wet oxidation was performed at the Ar reshaped-samples to observe the oxidation thickness with different crystal orientations.

식물추출물에 의한 벼 도열병균(Magnaprothe oryzae)의 ABC transporter발현 억제 및 포장에서의 방제

  • Ju, Myeong-Ho;Yeo, Yu-Mi;Choe, Pil-Seon;;Yang, Gwang-Yeol;Lee, Yeong-Jin
    • Proceedings of the Plant Resources Society of Korea Conference
    • /
    • 한국자원식물학회 2019년도 춘계학술대회
    • /
    • pp.37-37
    • /
    • 2019
  • 벼 재배포장에서 화학약제의 반복적인 사용으로 인한 병원균의 약제내성과 환경오염은 커다란 문제가 되고 있다. 이러한 약제내성을 극복하기 위한 노력의 하나로 유전자수준의 약제내성기작의 규명과 대체물질의 발굴이 필요하다고 사료된다. 이에 본 연구에서는 식물종이 지니는 광범위한 다양성에 주목하였고, 700여 종의 식물추출물을 벼 도열병균에 처리해 균사성장억제효과를 조사하는 선별실험을 실시하였고, 영릉향과 지모추출물이 높은 균사성장억제효과를 보이는 것을 확인했다. 영릉향과 지모 추출물이 화학약제를 대체하는 대안물질로서 가능성을 조사하기위해 균사성장억제능력 확인실험, 분획, HPLC (High Performance Liquid Chromatography), 포자발아 및 부착기 형성확인검정, ABC transporter의 발현조사, 환경독성실험등을 실시했다. 실험 결과, 영릉향과 지모 추출물을 벼 도열병균에 처리하였을 때 약제저항성유전자 ABC transporter의 기능이 저하되고 화학약제에 대한 내성이 감소를 확인했으며, 분획과 HPLC분석을 통해 영릉향과 지모의 유효성분을 확인했다. 또한, 실제 포장에서 영릉향 추출물과 지모 추출물을 사용하여 벼 도열병 방제가를 확인하는 포장시험을 실시한 결과, 각각 63%와 62%의 목 도열병 방제가를 확인 하였으며, 인축환경에 대한 유해성을 조사하기 위해 어류, 설치류, 중치류, 곤충을 대상으로 영릉향 추출물을 처리해 급성독성시험 실시한 결과, 고농도의 투여량에서도 독성이 없는 것을 확인했다. 위의 실험 결과를 토대로, 영릉향과 지모추출물이 화학농약에 의한 환경오염을 막을 수 있고, 인축과 환경에 피해를 입히지 않는 친환경자재로 친환경적인 생물농약의 신소재로서 가능성을 나타냈다고 사료된다.

  • PDF

Effects of F/M ratio on the EPS production and fouling at MBR (MBR에서 F/M비가 EPS 생성 및 fouling에 미치는 영향)

  • Kim, Yun-Ji;Choi, Yun-Jeong;Hwang, Sun-Jin
    • Journal of Korean Society of Water and Wastewater
    • /
    • 제35권3호
    • /
    • pp.197-204
    • /
    • 2021
  • In MBR, extracellular polymeric substance (EPS) is known as an important factor of fouling; soluble EPS (sEPS) affects internal contamination of membrane, and bound EPS (bEPS) affects the formation of the cake layer. The production of EPS changes according to the composition of influent, which affects fouling characteristics. Therefore, in this study, the effects of the F/M ratio on the sEPS concentration, bEPS content, and fouling were evaluated. The effects of F/M ratio on the amount and composition of EPS were confirmed by setting conditions that were very low or higher than the general F/M ratio of MBR, and the fouling occurrence characteristics were evaluated by filtration resistance distribution. As a result, it was found that the sEPS increased significantly with the increase of the F/M ratio. When the substrate was depleted, bEPS content decreased because bEPS was hydrolyzed into BAP and seemed to be used as a substrate. In contrast, when the substrate is sufficient, UAP (utilization-associated products) was rapidly generated in proportion with the consumption of the substrate. UAP has a relatively higher Protein/Carbohydrate ratio (P/C ratio) than BAP, and this means, it has a higher adhesive force to the membrane surface. As a result, UAP seems like causing fouling rather than BAP (biomass-associated products). Therefore, Rf (Resistance of internal contamination) increased rapidly with the increase of UAP, and Rc (Resistance of cake layer) increased with the accumulation of bEPS in proportion, and as a result, the fouling interval was shortened. According to this study, a high F/M ratio leads to an increment in UAP generation and accumulation of bEPS, and by these UAP and bEPS, membrane fouling is promoted.

Enhanced Electric Conductivity of Cement Composites by Functionalizing Graphene Oxide (산화그래핀 기능화에 의한 시멘트 복합체의 전기전도 특성 개선)

  • Jung-Geun Han;Jae-Hyeon Jeon;Young-Ho Kim;Jin Kim;Jong-Young Lee
    • Journal of the Korean Geosynthetics Society
    • /
    • 제22권1호
    • /
    • pp.1-7
    • /
    • 2023
  • This study has utilized self-assembled monolayers technology to improve electrical property of graphene-oxide, which has been seperated graphine powder through a chemical exfoliation. Aluminum sulfate (Al2(SO4)3) was applied on graphene-oxide as a reactant, and the fundamental research was carried out to apply on the self-sensing of cement-based construction structures. Electric resistance measurement result has shown that cement-composites with GO and Al-GO can be used as a conductor, electric resistance of GO and Al-GO contained composites improved by 10.2% and 15.9% respectively when compared to the standard cement-composite. Microstructure analyzation shown the formation of Al(OH)3 gel when Al-GO was added, which is speculated to result the smooth flow of current by improving the density of cement-composite. This implies that graphene-oxide has a possibility to be utilized as smart building materials and construction structure itself rather than just a structure.

Enhanced Device Performance of IZO-based oxide-TFTs with Co-sputtered $HfO_2-Al_2O_3$ Gate Dielectrics (Co-sputtered $HfO_2-Al_2O_3$을 게이트 절연막으로 적용한 IZO 기반 Oxide-TFT 소자의 성능 향상)

  • Son, Hee-Geon;Yang, Jung-Il;Cho, Dong-Kyu;Woo, Sang-Hyun;Lee, Dong-Hee;Yi, Moon-Suk
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • 제48권6호
    • /
    • pp.1-6
    • /
    • 2011
  • A transparent oxide thin film transistors (Transparent Oxide-TFT) have been fabricated by RF magnetron sputtering at room temperature using amorphous indium zinc oxide (a-IZO) as both of active channel and source/drain, gate electrodes and co-sputtered $HfO_2-Al_2O_3$ (HfAIO) as gate dielectric. In spite of its high dielectric constant > 20), $HfO_2$ has some drawbacks including high leakage current and rough surface morphologies originated from small energy band gap (5.31eV) and microcrystalline structure. In this work, the incorporation of $Al_2O_3$ into $HfO_2$ was obtained by co-sputtering of $HfO_2$ and $Al_2O_3$ without any intentional substrate heating and its structural and electrical properties were investigated by x-ray diffraction (XRD), atomic force microscopy (AFM) and spectroscopic ellipsometer (SE) analyses. The XRD studies confirmed that the microcrystalline structures of $HfO_2$ were transformed to amorphous structures of HfAIO. By AFM analysis, HfAIO films (0.490nm) were considerably smoother than $HfO_2$ films (2.979nm) due to their amorphous structure. The energy band gap ($E_g$) deduced by spectroscopic ellipsometer was increased from 5.17eV ($HfO_2$) to 5.42eV (HfAIO). The electrical performances of TFTs which are made of well-controlled active/electrode IZO materials and co-sputtered HfAIO dielectric material, exhibited a field effect mobility of more than $10cm^2/V{\cdot}s$, a threshold voltage of ~2 V, an $I_{on/off}$ ratio of > $10^5$, and a max on-current of > 2 mA.