• 제목/요약/키워드: (2,M)-filters

검색결과 388건 처리시간 0.025초

The Effect of Vacuum Pressure in Membrane Filtration Systems for the Efficient Detection of Bacteria from Natural Mineral Water

  • LEE, KI-YONG;CHANG-JAE WOO;TAE-RYEON HEO
    • Journal of Microbiology and Biotechnology
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    • 제8권2호
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    • pp.124-128
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    • 1998
  • The procedures currently used for determining microbiological quality of natural mineral water recommend filtration through membrane filters. In this study, we evaluated the effect of vacuum pressure for the accurate detection of bacteria from water samples seeded with Escherichia coli. We observed that the number of E. coli detected increased with increasing vacuum pressure. In order to examine the retention rate of bacteria in the holes of the membranes under the different pressures, the membrane filters were removed after filtration, washed with sterile water by vortexing, and placed on m-Endo agar plates. With all the filters tested, the number of E. coli retained within the filters at negative 600 mmHg was approximately 10 to $20\%$ higher than that obtained with 100 mmHg. These results demonstrate that the vacuum pressure exerted during the filtration procedure may affect the fixation of bacteria into some portions of openings in the membrane filter.

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A note on ordered filters of implicative semigroups

  • Jun, Young-Bae
    • Bulletin of the Korean Mathematical Society
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    • 제34권2호
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    • pp.185-191
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    • 1997
  • The notions of implicative semigroup and ordered filter were introduced by M. W. Chan and K. pp. Shum [3]. The first is a generalization of implicative semilattice (see W. C. Nemitz [6] and T. S. Blyth [2]) and has a close relation with the implication in mathematical logic and set theoretic difference (see G. Birkhoff [1] and H. B. Curry [4]). For the general development of implicative semilattice theory the ordered filters play an important role, which is shown by W. C. Nemitz [6].

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Some Fundamental Concepts in (2, L)-Fuzzy Topology Based on Complete Residuated Lattice-Valued Logic

  • Zeyada, Fathei M.;Zahran, A.M.;El-Baki, S.A.Abd;Mousa, A.K.
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제10권3호
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    • pp.230-241
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    • 2010
  • In the present paper we introduce and study fundamental concepts in the framework of L-fuzzifying topology(so called(2,L)-fuzzy topology)as L-concepts where L is a complete residuated lattice. The concepts of (2,L)-derived, (2,L)-closure, (2,L)-interior, (2,L)-exterior and (2,L)-boundary operators are studied and some results on above concepts are obtained. Also, the concepts of an L-convergence of nets and an L-convergence of filters are introduced and some important results are obtained. Furthermore, we introduce and study bases and subbases in (2,L)-topology. As applications of our work the corresponding results(see[10-11]) are generalized and new consequences are obtained.

A Study on the Removal of SOx and NOx Using Catalytic Ceramic Filters (촉매담지 세라믹 필터를 이용한 황산화물과 질소산화물의 제거에 관한 연구)

  • 홍민선;이동섭
    • Journal of Korean Society for Atmospheric Environment
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    • 제14권5호
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    • pp.455-464
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    • 1998
  • Removal teals of Soxmox were performed using low density ceramic filters doped with various catalysts. Disc type (50 mmO.Dx10 mmt) low density ceramic filters were doped with three different catalysts such as Cu to remove SOx and NOx, and Mn and Co to remove NOx. The air permeabilities and specific surface areas were 40~50cc/min.cm2.cmH2O and 4.1~8.88 m2/g, respectively. Also, the peak pore sizes of catalyst support were 3~5nm. Tests were focused to search optimum operating temperatures for different catalysts. It was found that as the CuO content increases, SOx removal efficiency was increased. NOx removal efficiencies for Mn, Cu and Co, were 85% at 30$0^{\circ}C$, 90% at 40$0^{\circ}C$ and 90% at 45$0^{\circ}C$, respectively.

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Filter wheel design for CQUEAN II

  • Kim, Sanghyuk;Pak, Soojong;Lee, Hye-In;Im, Myunshin;Shin, Sang-Kyo
    • The Bulletin of The Korean Astronomical Society
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    • 제39권1호
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    • pp.51.2-51.2
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    • 2014
  • CQUEAN(Camera for QUasars in EArly uNiverse) has been used at the 2.1 m Otto Struve Telescope of the McDonald Observatory since 2010. This camera is optimized at 0.7 - 1.1 um for the survey of Lyman break of high redshift (z > 5) quasars in the early universe. The current system has a filter wheel consist of seven (g', r', I', z', Y, Iz and Is) broad-band filters. We are upgrading this filter wheel to have 20 narrow band filters, with which we can take spectral energy distributions of targets. The new filter wheel consists of interchangeable cartridges for 50 mm square filters, a speed reducer unit, and a step motor. This new design of the large size filter wheel can be applied to other large format CCD cameras.

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MORE GENERAL FORMS OF (∈, ∈ VQk) FUZZY FILTERS OF ORDERED SEMIGROUPS

  • Khan, Asghar;Muhammad, Shakoor;Khalaf, Mohammed M.
    • Honam Mathematical Journal
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    • 제39권2호
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    • pp.199-216
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    • 2017
  • In the paper [Y. B. Jun, B. Davvaz and A. Khan, Filters of ordered semigroups based on the fuzzy points, JIFS 24 (2013) 619-630]. Jun et al. discussed the notion of (${\in},{\in}{\vee}q_k$)-fuzzy left (resp., right) filters as a generalization of the notion of (${\in},{\in}{\vee}q$)-fuzzy left (resp., right) filters of ordered semigroups. In this article, we try to obtain a more general form that (${\in},{\in}{\vee}q_k$)-fuzzy left (resp., right) filters in ordered semigroups. The notion of (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp., right) filters is discussed, and several properties are investigated. Characterizations of an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp., right) filter are established. A condition for an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp., right) filter to be a fuzzy left (resp., right) filter is provided. The important achievement of the study with an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (right) filter is that the notion of an (${\in},{\in}{\vee}q_k$)-fuzzy left ( right) filter and hence an (${\in},{\in}{\vee}q$)-fuzzy left (resp. right) filter are special cases of an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp. right) filter, and thus several results in published papers are becoming corollaries of our results obtained in this paper.

Fabrication of Superconducting Narrow Bandpass Filters with Parallel Microstrip Line (마이크로스트립 평행결합선을 이용한 초전도 협대역 필터의 제작)

  • Park, Joo-Hyung;Lee, Sang-Yeol;Yoon, Hyung-Kuk;Yoon, Young-Joong
    • Proceedings of the KIEE Conference
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    • 대한전기학회 1998년도 하계학술대회 논문집 D
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    • pp.1549-1551
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    • 1998
  • We have designed and developed narrow bandpass multipole filters for satellite communication using $YBa_2Cu_3O_{7-x}$(YBCO) thin films on MgO substrates. The superconducting film used in this study was prepared by laser ablation on one side polished MgO (100) substrates. A Nd:YAG laser was used to fabricate YBCO thin films. The wave length of the laser was 355 nm. The laser beam was focused onto a YBCO target rotating linearly to avoid deep craters that may eject macroscopic YBCO particles. The YBCO films were grown at $750^{\circ}C$ in the oxygen partial pressure of 200 mTorr. The deposited YBCO thin films were patterned by conventional wet-etching method. The transition temperatures of YBCO thin films were 85 - 88 K and the film thicknesses were about 5,000 $\AA$. By comparing the performances of normal-metal filters and YBCO filters, we observed that superconducting YBCO multipole filters have been showed superior performances at 77 K.

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Characteristics of Ionic Components in Size-resolved Particulate Matters in Suwon Area (수원지역 분진의 입경별 이온성분 분포특성에 관한 연구)

  • Oh, Mi-Seok;Lee, Tae-Jung;Kim, Dong-Sool
    • Journal of Korean Society for Atmospheric Environment
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    • 제25권1호
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    • pp.46-56
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    • 2009
  • The main purpose of this study was to investigate air quality trends of ambient aerosol with obtaining size-fractionated information. The suspended particulate matters were continuously collected on membrane filters and glass fiber filters by an 8-stage cascade impactor for 2 years (Sep. 2005 $\sim$ Sep. 2007) in Kyung Hee University-Global Campus. 8 ionic species ($Na^+$, ${NH_4}^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, ${NO_3}^-$, and ${SO_4}^{2-}$) were analyzed by an IC after performing proper pretreatments of each sample filter. The average concentration levels of each ion were $9.24{\mu}g/m^3$ of ${SO_4}^{2-}$, $7.35{\mu}g/m^3$ of ${NO_3}^-$, $2.81{\mu}g/m^3$ of ${NH_4}^+$, $2.11{\mu}g/m^3$ of $Ca^{2+}$, $1.65{\mu}g/m^3$ of $Cl^-$, $1.87{\mu}g/m^3$ of $Na^+$, $0.80{\mu}g/m^3$ of $Mg^{2+}$, and $0.54{\mu}g/m^3$ of $K^+$, respectively. The distribution pattern of $Na^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, and ${NO_3}^-$ was bi-modal and two peaks appeared in the range of $0.4{\sim}0.7{\mu}m$ and $3.3{\sim}4.7{\mu}m$, respectively. On the other hand, ${SO_4}^{2-}$, ${NH_4}^+$, and $K^+$ showed patterns of uni-modal distribution, mostly abounded in the fine mode group.

ON FUZZY ${\beta}-COMPACT^*$ SPACES AND FUZZY $\beta$-FILTERS

  • Uma, M.K.;Roja, E.;Balasubramanian, G.
    • East Asian mathematical journal
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    • 제23권2호
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    • pp.151-158
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    • 2007
  • In this paper we introduce the concept of fuzzy ${\beta}-compact^*$ spaces. Besides giving some interesting properties of fuzzy ${\beta}-compact^*$ spaces we also give a characterization on fuzzy $\beta$-compact spaces by making use of newly introduced concept of fuzzy $\beta$-filters.

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Analysis of UV Filters in Water using Stir Bar Sorptive Extraction (SBSE) and GC/MS-MS (교반막대 추출법과 GC/MS-MS를 이용한 수중의 자외선 차단제 분석)

  • Seo, Chang-Dong;Son, Hee-Jong;Jung, Jong-Moon;Choi, Jin-Taek;Jang, Seong-Ho
    • Journal of Environmental Science International
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    • 제23권6호
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    • pp.1037-1047
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    • 2014
  • A highly sensitive analytical method based on stir bar sorptive extraction (SBSE) technique and gas chromatography/tandem mass spectrometry (GC/MS-MS) has been developed, allowing the simultaneous multi-analyte determination of seven UV filters in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 40 mL of water sample at pH 3 and stirred at 1,100 rpm for 120 min. Other SBSE parameters (salt effect and presence of organic solvent) were optimised. The method shows good linearity (coefficients > 0.990) and reproducibility (RSD < 12.9%). The extraction efficiencies were above 84% for all the compounds. The limits of detections (LOD) and limits of quantification (LOQ) were 2.1~8.6 ng/L and 6.8~27.5 ng/L, respectively. The developed method offers the ability to detect 8 UV filters at ultra-low concentration levels with only 40 mL of sample volume. Matrix effects in tap water, river water, wastewater treatment plant (WWTP) final effluent water and seawater were investigated and it was shown that the method is suitable for the analysis of trace level of 7 UV filters except of benzophenone (BP). The method developed in the present study has the advantage of being rapid, simple, high-sensitive and both user and environmentally friendly.