• 제목/요약/키워드: $\Delta$L

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ON A GENERALIZED DIFFERENCE SEQUENCE SPACES OVER NON-ARCHIMEDIAN FIELDS AND RELATED MATRIX TRANSFORMATIONS

  • BATAINEH AHMAD H. A.;AL-ZA'AREER HAMZA B.
    • 대한수학회논문집
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    • 제20권4호
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    • pp.723-729
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    • 2005
  • Let F be a non-trivial non-Archimedian field. The sequence spaces $\Gamma\;(F)\;and\;{\Gamma}^{\ast}(F)$ were defined and studied by Soma-sundaram[4], where these spaces denote the spaces of entire and analytic sequences defined over F, respectively. In 1997, these spaces were generalized by Mursaleen and Qamaruddin[1] by considering an arbitrary sequence $U\;=\;(U_k),\;U_k\;{\neq}\;0 \;(\;k\;=\;1,2,3,{\cdots})$. They characterized some classes of infinite matrices considering these new classes of sequences. In this paper, we further generalize the above mentioned spaces and define the spaces $\Gamma(u,\;F,\;{\Delta}),\;{\Gamma}^{\ast}(u,\;F,\;{\Delta}),\;l_p(u,\;F,\;{\Delta})$), and $b_v(u,\;F,\;{\Delta}$). We also study some matrix transformations on these new spaces.

불균일 벽면 온도를 갖는 Rayleigh-Benard 문제에서의 유동의 다수성 (Multiplicity of Flows in a Rayleigh-Benard Problem with Non-Uniform Wall Temperatures)

  • 유주식;김용진
    • 대한공업교육학회지
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    • 제30권2호
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    • pp.123-129
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    • 2005
  • A Rayleigh-Benard problem with non-uniform wall temperatures of the form, $T_L=T_1+{\delta}{\Delta}T{\sin}kx$ and $T_U=T_2-{\delta}{\Delta}{\sin (kx)$, is numerically investigated. In the conduction-dominated regime with small a Rayleigh number, a two-tier structure appears with two counter-rotating rolls stacked on the top of each other. The flow becomes unstable with increase of the Rayleigh number, and multicellular convection occurs above a critical Rayleigh number. The multicellular flows at high Rayleigh numbers consist of approximetely square-shape cells. Four multiple flows and dual flows classified by the number of cells are found at k=0.5 and k=1, respectively.

$YBaCo_2O_{5+{\delta}}$ 세라믹 분리막의 산소투과 특성 (Characteristics of Oxygen Permeation on $YBaCo_2O_{5+{\delta}}$ Ceramic Membrane)

  • 표대웅;김종표;박정훈
    • 멤브레인
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    • 제22권2호
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    • pp.113-119
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    • 2012
  • $YBaCo_2O_{5+{\delta}}$조성의 산화물을 고상반응법을 이용하여 합성하였으며, 합성된 분말은 압축 성형 후 $1,180^{\circ}C$에서 소결하여 치밀한 분리막을 제조하였다. $YBaCo_2O_{5+{\delta}}$ 분리막은 X-선 회절분석기(XRD)와 전자 주사 현미경(SEM)을 이용하여 분석하였다. XRD 분석결과 $1,150^{\circ}C$ 이상에서 다른 불순물 없이 이중층 페롭스카이트 구조가 얻어졌다. 산소투과량은 분리막 양면에 산소분압 차이에 따라 $750{\sim}950^{\circ}C$ 온도범위에서 측정하였다. 산소투과량은 온도와 산소분압이 증가할수록 증가하였고, 두께 1.0 mm의 $YBaCo_2O_{5+{\delta}}$ 분리막은 $950^{\circ}C$, $PO_2$ = 0.42 atm에서 약 0.15 mL/$cm^2{\cdot}min$의 최대 투과량을 보였다. 산소투과에 대한 활성화 에너지는 산소 분압이 감소할수록 감소하였고 $PO_2$ = 0.21 atm의 조건에서 76.0 kJ/mol이었다.

공급 측과 투과 측 조건에 따른 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) 관형 분리막의 산소투과 특성 (Oxygen Permeation Properties of Tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) Membranes under Different Condition of Feed Side and Permeate Side)

  • 김종표;박정훈;이용택;최영종
    • 멤브레인
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    • 제21권2호
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    • pp.155-162
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    • 2011
  • $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) 조성을 갖는 치밀한 관형 분리막은 압출 성형 방법으로 제조하였다. $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 구조적 특성은 x-선 회절분석기 (XRD)와 전자 주사 현미경 (SEM)을 이용하여 분석하였으며, 상대밀도는 94.10%를 보였다. 산소투과량 분석은 700~$950^{\circ}C$ 범위에서 공급 측과 투과 측의 운전조건에 따라 측정되었다. 공급 측과 투과 측에서 대기 중 공기와 진공펌프를 사용할 경우, $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 산소투과량은 $900^{\circ}C$에서 1.37 mL/$min{\cdot}cm^2$로 높게 나타났다.

질소 동위원소비를 이용한 관행농업과 유기농업에서의 질산태 질소 오염원 구명 (Investigation of Nitrate Contamination Sources Under the Conventional and Organic Agricultural Systems Using Nitrogen Isotope Ratios)

  • 고한종;최홍림;김기연
    • Journal of Animal Science and Technology
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    • 제47권3호
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    • pp.481-490
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    • 2005
  • Nitrate contamination in water system is a critical environmental problem caused by excessive application of chemical fertilizer and concentration of livestock. In order to prevent further contamination, therefore, it is necessary to understand the origin of nitrate in nitrogen loading sources and manage the very source of contamination. The objective of this study was to examine the nitrate contamination sources in different agricultural system by using nitrogen isotope ratios. Groundwater and runoff water samples were collected on a monthly basis from February 2003 to November 2003 and analyzed for nitrogen isotopes. The nitrate concentrations of groundwater in livestock fanning area were higher than those in conventional and organic fanning area and exceeded the national drinking water standard of 10mg N/ l. The ${\delta}^{15}N$ranges of chemical fertilizer and animal manure were - 3.7${\sim}$+2.3$\textperthousand$ and +12.5${\sim}$26.7$\textperthousand$, respectively. The higher ${\delta}^{15}N$ of animal manure than those of chemical fertilizer reflected isotope fractionation and volatilization of '''N. The different agricultural systems and corresponding average nitrate concentrations and ${\delta}^{15}N$ values were: conventional farming, 5.47mg/e, 8.3$\textperthousand$; organic fanning, 5.88mg/e, 10.1$\textperthousand$; crop-livestock farming, 12.5mg/e, 17.7%0. These data indicated that whether conventional or organic agriculture effected groundwater and runoff water quality. In conclusions, relationship between nitrate concentrations and ${\delta}^{15}N$ value could be used to make a distinction between nitrate derived from chemical fertilizer and from animal manure. Additional investigation is required to monitor long-term impact on water quality in accordance with agricultural systems.

Rhodocyclus gelatinosus KUP-74의 휴지균체를 이용한 ${\delta}-Aminolevulinate$의 생산 (Production of ${\delta}-Aminolevulinate$ by Using the Resting Cells of Rhodocyclus gelatinosus KUP-74)

  • 이소희;안영철;임왕진;황세영
    • Applied Biological Chemistry
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    • 제37권6호
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    • pp.427-432
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    • 1994
  • 광합성세균인 Rhodocyclus gelatinosus KUP-74의 휴지균체에 의한 균체외 ${\delta}-aminolevulinate$(ALA) 생산 효율성에 관하여 검토하였다. 균체외 ALA의 최대 생산치를 위하여 1 ml ALA 생산계는 1.05 mg의 휴지균체로 6시간의 배양을 필요로 하였다. 또한, 이 조건에서 ALA 생산의 유도물질인 levulinate나 L-glutamate 등은 균체외 ALA 생산에 있어서 비교적 낮은 효과를 나타내었다. 반면에, ALA 생산계의 부피와 이에 적합한 균체밀도가 효과적인 ALA 생산을 위하여 중요한 요인으로 나타났다. 휴지균체의 안정한 ALA 생산유지를 위한 수명은 휴지균체를 고정화 시키므로써 크게 연장되었다.

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그라비어 인쇄에서의 G7 Calibration 적용에 관한 연구 (A Study on the G7 Calibration Application in Gravure Printing)

  • 장영엽;오성상;조가람;이재수
    • 한국인쇄학회지
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    • 제31권1호
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    • pp.65-78
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    • 2013
  • In gravure printing ink in printed flexible packaging considering the characteristics of the study more accurate color management options and results were as follows. When applying G7 calibration, P2P of the target GRACol G7 evaluate the delta $L^*$ and delta $F^*$, CMY and K-scale average of the results of delta $L^*$ and the highest tolerance G7 average of 1.5 and 3.0 are included in all the best. In addition, the average delta $F^*$ and super delta $F^*$, G7 tolerance by being included within the scope of color management, G7 calibration was possible. Target IT 8.7/4 CMYK, when applied to the calibration G7, Color gravure printing machine is applied to the average of the previous decreased from 12.4 to 3.6. In addition, if a digital proof is EPSON WT 7900 the average color applied to the previous reduction from 5.24 to 0.74 because of the gravure printing color proofing system was effective in the management. G7 calibration by applying the reference print profile of the Epson WT 7900-G-icc, the average was 0.74 coloration, and gravure-G-icc cases, the average color of the 3.60 per GRACol average of all the five colors below were included within the allowable range. Thus, the flexible packaging gravure printing color management of printed after applying the first G7 calibration, the results refer to the press by the profiling, and where best to take advantage of the profile creation was good.

Arsenic removal from drinking water by direct contact membrane distillation

  • Zoungrana, Ali;Zengin, Ismail H.;Elcik, Harun;Yesilirmak, Dilara;Karadag, Dogan;Cakmakci, Mehmet
    • Membrane and Water Treatment
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    • 제7권3호
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    • pp.241-255
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    • 2016
  • In this study, the treatability of arsenic (As) contaminated water by direct contact membrane distillation (DCMD) at different delta temperatures (${\Delta}T$) 30, 40 and $50^{\circ}C$ has been investigated. Two different pore sizes ($0.22{\mu}m$ and $0.45{\mu}m$) of hydrophobic membranes made of polyvinylidene fluoride (PVDF) were used. The membrane pore sizes, the operating temperatures, the feed solution As concentration and conductivity have been varied during the experimental tests to follow the removal efficiency and flux behavior. Both membranes tested had high removal efficiency of arsenite (As (III)) and arsenate (As (V)) and all permeates presented As concentration far lower than recommended $10{\mu}g/L$ of world health organization (WHO). As concentration was below detection limit in many permeates. Conductivity reduction efficiency was over 99% and the transmembrane flux (TMF) reached $19L/m^2.h$ at delta temperature (${\Delta}T$) of $50^{\circ}C$ with PVDF $0.45{\mu}m$ membrane. The experimental results also indicated that $0.45{\mu}m$ pore sizes PVDF membranes presented higher flux than $0.22{\mu}m$ pore sizes membranes. Regardless of all operating conditions, highest fluxes were observed at highest ${\Delta}T$ ($50^{\circ}C$).

(Pb,Ba)(Zr,Ti)$O_3$계 세라믹스의 )$Y_2O_3$첨가에 따른 유전 및 전왜 특성 (Dielectric and electrostrictive properties of (Pb,Ba)(Zr,Ti))$O_3$ ceramics with $Y_2O_3$addition)

  • 김규수;윤광희;윤현상;홍재일;유주현;박창엽
    • E2M - 전기 전자와 첨단 소재
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    • 제9권6호
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    • pp.551-557
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    • 1996
  • To decrease the hysteresis of electric field induced strain, $Y_{2}$ $O_{3}$ dopant of which amount is 0-0.8wt% was added to the (P $b_{0.73}$B $a_{0.27}$)(Z $r_{0}$ 75/ $Ti_{0.25}$) $O_{3}$ ceramics. Electromechanical coupling coefficients of the specimen with 0.1 Wt% $Y_{2}$ $O_{3}$ were $k_{p}$=26.9% and $k_{31}$ =20.4%, which exhibited the maximum value at the constant bias electric field of 10 kV/cm. At the same $Y_{2}$ $O_{3}$ addition amount, electric field piezoelectric constant ( $d_{3l}$) and strain(.DELTA.l/l) showed the maximum values of 139.6*10$^{-12}$ [C/N] and 126*10$^{-6}$ .DELTA. l/l respectively at 10 kV/cm electric field. And the hysteresis of strain showed the minimum value of 17.5%. So, we propose that it is possible to apply PBZT system with $Y_{2}$ $O_{3}$ dopant to the electrostrictive actuator.r.r.

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단열 및 등온수평 경계조건을 갖는 직각 밀폐용기내 공기의 자연대류 열전달 (Natural Convection Heat Transfer in Rectangular Air Enclosures With Adiabatic and Isothermal Horizontal Boundary Conditions)

  • 이진호;김무현;모정하
    • 대한기계학회논문집
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    • 제14권1호
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    • pp.207-213
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    • 1990
  • 본 연구에서는 종횡비(aspect ratio` A=H/L)가 1 이하인 직각밀폐용기내 수평 경계면이 자연대류열전달에 미치는 영향을 조사하기 위해 단열조건인 경우와 등온조건 인 경우 { $T_{H}$.simeq. $T_{T}$$T_{C}$.simeq. $T_{B}$, 따라서 온도차의 비, .DELTA. $T_{V/}$ .DELTA. $T_{H}$=( $T_{T}$- $T_{B}$)/( $T_{H}$- $T_{C}$).simeq.1} Mach-Zehnder간섭계 및 수치해석 을 통해 온도장 및 각 면에서의 열전달특성의 차이를 자세히 구명하였다. 특히 등온 수평면조건인 경우 상부수평면온도가 하부수평면온도보다 높을 때 ( $T_{T}$$T_{B}$) 직각용기내는 수직방향으로 안정된 온도구배가 형성되어, 양단온도차(.DELTA. $T_{H}$= $T_{H}$- $T_{C}$)에 의해 기본적으로 존재하는 자연대류흐름을 억제하게 된다. 이때 자연대류흐름의 억제정도를 나타내는 주요 물리적 변수로서 온도차의 비, .DELTA. $T_{V/}$ .DELTA. $T_{H}$가 있다. 이러한 물리적 현상은, 기본적으로 존재하는 유체내 자연대류효 과를 억제함으로써 중력장하에서 양질의 결정을 얻고자 하는 결정성장(growth of cry- stal)등에 관계된다. 본 연구는 실험유체가 공기이고 .DELTA. $T_{V/}$.DELTA. $T_{H}$=1인 경우 를 택하여 일반적인 단열조건의 경우와 열전달특성의 차이를 비교한 것이다.전달특성의 차이를 비교한 것이다.다.전달특성의 차이를 비교한 것이다.