• 제목/요약/키워드: Al concentration

검색결과 1,828건 처리시간 0.031초

Cosputtering법으로 증착한 ZnO박막의 Al도핑농도가 미세구조 및 물리적 특성에 끼치는 효과 (Effects of Al Doping Concentration on the Microstructure and Physical Properties of ZnO Thin Films Deposited by Cosputtering)

  • 임근빈;이종무
    • 한국재료학회지
    • /
    • 제15권9호
    • /
    • pp.604-607
    • /
    • 2005
  • Dependence of the crystallinity, surface roughness, carrier concentration, carrier mobility, electrical resistivity and transmittance of Al-doped ZnO films deposited on glass substrates by RF-magnetron sputtering on effects of the ratio of the RF power for AlZnO to that for ZnO (R) have been investigated. X-ray diffraction spectra show strong preferred orientation along the c-axis. The full width at half maximum (FWHM) of the ZnO (002) peak decreases slightly as R increases in the range of R<1.0, whereas it increases substantially in the range of R>1.0. Scanning electron micrographs (SEM) show that the ZnO film surface becomes coarse as R increases. The carrier concentration and the carrier mobility in the ZnO thin film are maximal for R=1.5 and 1.0, respectively. The electrical resistivity is minimal for R=1.0 The transmittance of the ZnO:Al film tends to increase, but to decrease slightly in the range of R>0.5. It may be concluded that the optimum R value is 1.0, considering all these analysis results. The cause of the changes in the structure and physical properties of ZnO thin films with R are also discussed.

Alcaligens eutrohus 고농도 배양액으로부터 알루미늄(Al)계 응집제를 이용한 세포분리 (Cell separation from high density culture broths of Alcaligenes eutrophus by using Al-based coagulants)

  • 조경숙;류희욱;정현우;곽종운;장용근
    • KSBB Journal
    • /
    • 제13권3호
    • /
    • pp.272-278
    • /
    • 1998
  • Cell recovery from high cell density broths of Alcaligenes eutrophus by pretreatment with aluminum-based coagulants such as aluminum sulfate, polyaluminum hydrooxide chloride silicate (PACS), and polyaluminum hydrooxide chloride (Hi-PAX) was carried out. Cells coagulated with coagulants could be successfully recovered above 95-99% by centrifugation or filtration. The optimum initial pH of fermentation broths for cell recovery was in the range of 10 to 12. Optimum coagulants dosage for cell recovery increased with increasing of cell concentrations (21-160 g/L). The optimum coagulant dosages to recover cells with more than 95% cell recovery by centrifugation for the cell concentrations ranged 21-160 g/L were as follows: aluminum sulfate, 416-1708 mg Al/L; PACS, 211-826 mg Al/L; Hi-PAX, 320-960 mg Al/L. At optimum conditions for the coagulation of cells, centrifugal forces for 95% of cell recovery were dependent on the cell concentration. The centrifugal forces at 82 g/L and 160 g/L of cell concentration were only 45${\times}$g and 1600${\times}$g, respectively.

  • PDF

AlN 반도체와 Cu의 도핑 농도에 대한 자성 (Magnetic Properties of Cu-doped AlN Semiconductor)

  • 강병섭;이행기
    • 반도체디스플레이기술학회지
    • /
    • 제9권3호
    • /
    • pp.1-4
    • /
    • 2010
  • First-principles calculations based on spin density functional theory are performed to study the spin-resolved electronic properties of AlN doped with a Cu concentration of 6.25%-18.75%. The ferromagnetic state is more energetically favorable state than the antiferromagnetic state or the nonmagnetic state. For $Al_{0.9375}Cu_{0.0625}N$, a global magnetic moment of 1.26 mB per supercell, with a localized magnetic moment of 0.75 $m_B$ per Cu atom is found. The magnetic moment is reduced due to an increase in the number of Cu atoms occupying adjacent cation lattice position. For $Al_{0.8125}Cu_{0.1875}N$, the magnetism of the supercell disappears by the interaction of the neighboring Cu atoms. The nonmagnetic to ferromagnetic phase transition is found to occur at this Cu concentration. The range of concentrations that are spin-polarized should be restricted within very narrow.

Effects of Aluminium on Vitellogenin and Its mRNA Induction by Estradiol-17$\beta$ in the Primary Culture of Hepatocytes in the Rainbow Trout Oncorhynchus mykiss

  • Hwang, Un-Gl;Park, Jin-Il;Shim, Jung-Min;Jung, Chang-Soo;Park, Sung-Yoon
    • 한국환경과학회:학술대회논문집
    • /
    • 한국환경과학회 2003년도 International Symposium on Clean Environment
    • /
    • pp.159-164
    • /
    • 2003
  • Effects of Al on vitellogenin (VTG) and VTG mRNA induction by estradiol-17 $\beta$($E_2$) were examined in primary hepatocyte culture of rainbow trout. Hepatocytes were precultured for 2 days and then E2 ($2{\times}10^{-6}$M) and Al ($10^{-6}-10^{-4}$M) were simultaneously added to the incubation medium. Hepatocytes were cultured for 5 more days. Media and hepatocytes were then analyzed by SDS-PAGE and Northern blotting for VTG and VTG mRNA, respectively. These metal had no appreciable effect on the viability of hepatocytes in culture. However, Al interfered with VTG production and VTG mRNA expression. Al reduced VTG production in a concentration-dependent way and a significant reduction accurred at Al concentrations greater than $5{\times}10^{-5}$M. VTG mRNA expression also decreased with a negative correlation with Al concentration (r=-0.98). These results suggest that Al inhibit VTG production at the transcriptional level to reduce VTG mRNA expression.

  • PDF

PAC 전처리 시 수소이온 농도에 따라 발생 가능한 알루미늄 종에 의한 나노여과막 성능 연구 (Effects of polymeric Al and hydrolysis products of PAC at different pH on performance of nanofiltration with PAC coagulation pretreatment)

  • 최양훈;권지향
    • 상하수도학회지
    • /
    • 제24권1호
    • /
    • pp.15-24
    • /
    • 2010
  • Coagulation can be used for pretreatment of NF membrane filtration. Foulants such as organic matter and particulate can be removed effectively with the process while high flux recovery is maintained. Recently various types of polyaluminium coagulants including polyaluminium chloride(PAC) are commercially available for water treatment. This study examines effects of polymeric Al and hydrolysis products of PAC on nanofiltration membrane performance. Dominant hydrolysis products were polymeric Al, $Al(OH)_3$, and ${Al(OH)_4}^{-1}$ at acidic, neutral, and alkaline pH conditions, respectively. Under acidic pH condition, flux decline was increased with increasing PAC concentrations, possibly due to polymeric Al adsorption on membrane pore and/or surfaces. For neutral and alkaline pH conditions, little flux decline was observed with increasing PAC concentrations except the highest ${Al(OH)_4}^{-1}$ concentration, with which rapid flux decline was shown. Removal of ionic matters was also varied with pH conditions in this study. Especially, conductivity removal was substantially low and $Ca^{2+}$ concentration in the permeate was quite high at neutral pH condition.

나노 다이아몬드 입자를 첨가한 엔진 오일의 알루미늄 6061 합금에 대한 마모 특성 (Wear Characteristics of Lubricant with Nano-diamond Particles on Al-6061 Aluminum Alloy)

  • 황성완
    • 한국기계가공학회지
    • /
    • 제20권12호
    • /
    • pp.16-23
    • /
    • 2021
  • Pin-to-disc wear testing experiments were conducted to investigate the wear characteristics of commercial oil (5W-40) with nano-diamond particles. The upper specimen was a SUJ-2 high-carbon chromium steel ball with a diameter of 4 mm, and the lower specimen was made of the Al-6061 alloy. The applied load was 5 N, and the sliding speed was 0.25 m/s. The wear tests were conducted at a sliding distance of 500 m. The friction coefficients and wear rates of the Al-6061 specimens were tested using commercial oil with different nano-diamond concentrations ranging from 0 to 0.02 wt.%. The addition of nano-diamond particles to commercial oil reduced both the wear rate and coefficient of friction of the Al-6061 alloy. The use of nano-diamond particles as a solid additive in oil lubricants was found to improve the tribological behavior of the Al-6061 alloy. For the Al-6061 alloy, the optimal concentration was found to be 0.005 wt.% in view of the friction coefficient and wear rate. Further investigation is needed to determine the optimal concentration of nano-diamond particles for various loadings, sliding speeds, oil temperatures, and sliding distances.

미선나무 잎 추출물을 이용한 음료 개발 및 이화학적 특성 (Beverage Development using Abeliophyllum distichum Leaf Extract and Its Physicochemical Properties)

  • 이호진;권순영;정필문;김은아;이경행
    • 한국식품영양학회지
    • /
    • 제36권2호
    • /
    • pp.122-128
    • /
    • 2023
  • A beverage was developed using the Abeliophyllum distichum leaf (AL). The beverage was prepared by adding it to apple juice by concentration, and physicochemical quality, antioxidant activities, and sensory evaluation were measured. Soluble solid and reducing sugar content of the control were 12.57 °Brix and 11.40%, respectively, and there was no difference from the group with addition of the AL extract. However, pH was slightly increased upon addition of AL extract. Lightness and yellowness increased when AL extract was added. Verbascoside content was not detected in the control, but it increased as the concentration of AL extract increased. The contents of ascorbic acid and flavonoids were 5.38 and 20.42 mg%, respectively, and there was no significant difference between the groups. However, the content of polyphenols increased as the concentration of the AL extract increased. DPPH radical and metal ion scavenging activity were increased by addition of the AL extract, but there was no difference in the ABTS radical scavenging activity. As a result of the sensory evaluation, there was no difference from the control even wihen the AL extract was added; thus, it was considered that there was no problem with the degree of acceptability when added within about 300 ppm.

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

  • 이인환;김덕규;김홍배
    • 한국진공학회지
    • /
    • 제19권3호
    • /
    • pp.206-210
    • /
    • 2010
  • RF 마그네트론 스퍼터링법을 이용하여 Al 도핑된 ZnO 박막을 Ar 유량에 따라 증착하고 박막의 다양한 특성을 연구하였다. ZnO 박막의 Ar 유량 변화를 통해 고품질 박막을 증착할 수 있었고 Al 도핑된 ZnO 박막에 대한 Ar 유량의 영향을 확인하였다. 모든 Al 도핑된 ZnO에서 80% 이상의 좋은 투과도를 보였다. Hall 측정과 X-ray photoelectron spectrometer 측정 결과, 비저항이 가장 작은 60 sccm에서 가장 작은 Al 도핑 농도를 보였다. Ar 유량에 따른 Al 도핑된 ZnO 박막에서의 전기적인 특성은 Al 도핑 농도보다 산소 공공에 의해 더 영향을 받음을 확인하였다.

전기자동차 배터리 하우징용 6061-T6 알루미늄합금의 전식 특성에 미치는 염화물농도 및 인가전류밀도의 영향 (Effects of Chloride Concentration and Applied Current Density on Stray Current Corrosion Characteristics of 6061-T6 Al Alloy for Electric Vehicle Battery Housing)

  • 신동호;김성종
    • Corrosion Science and Technology
    • /
    • 제21권5호
    • /
    • pp.348-359
    • /
    • 2022
  • Interest in electric vehicle is on the rise due to global eco-friendly policies. To improve the efficiency of electric vehicles, it is essential to reduce weights of components. Since electric vehicles have various electronic equipment, the research on stray current corrosion is required. In this research, a galvanostatic corrosion experiment was performed on 6061-T6 Al alloy for electric vehicle battery housing using chloride concentration and applied current density as variables in a solution simulating an acid rain environment. As a result of the experiment, when chloride concentration and applied current density were increased, corrosion damage became larger. In particular, pitting damage was dominant at an applied current density of 0.1 mA/cm2. Pitting damage over the entire surface was found at a current density of 1.0 mA/cm2. In conclusion, chloride concentration had a relatively large effect on localized corrosion. The applied current density had a great effect on uniform corrosion. However, in the case of applied current density, localized corrosion was also greatly affected by interaction with chloride.

Al 2024를 이용한 Conflat Flange Gasket의 특성 (Characteristics of Al 2024 Conflat Flange Gaskets)

  • 이철로;박재홍;홍승수;임재영;신용현;정광화
    • 한국진공학회지
    • /
    • 제1권2호
    • /
    • pp.237-243
    • /
    • 1992
  • Two gaskets of Al 2024-T4 and annealed al 2024-T4 were made. We had acquired 2 $\times$ 10-12torr in a chamber using them. Microstructures, hardness and stress concentration of the gaskets were examined before and after baking. Knife edge damages such as decrease of edge height(H) and increase of edge angle() were found on knife edges when the Al 2024-T4 gasket was used. But no damage was found with the annealed Al 2024 gasket.

  • PDF