• 제목/요약/키워드: (2,M)-filters

검색결과 388건 처리시간 0.029초

Dust Removal Efficiency and Operation Characteristics of Metal Filters for Coal Gasification Fines and Standard Dust Sample (금속필터를 사용한 석탄가스화 분진 및 표준 분진의 집진 효율과 운전특성)

  • Yun, Yongseung;Chung, Seok Woo;Lee, Seung Jong
    • Korean Chemical Engineering Research
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    • 제57권4호
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    • pp.461-468
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    • 2019
  • Demand for improving dust removal efficiency in coal power plants and the dust removal requirement to the level of capturing fine particulate matter and ultrafine particles have been increasing. While bag filter and electrostatic precipitator (ESP) are typically used for dust removal in the processes operating at atmospheric pressure, metal filters or ceramic filters are employed for dust which is produced at high temperature/pressure system as in coal gasification. For dust removal at the high temperature/pressure conditions, two metal filters of five compressed/sintered layers were manufactured and applied to analyze the dust removal characteristics. Manufactured metal filters exhibited more than 99% dust removal efficiency on coal gasification fine particulates in mass basis. To evaluate the fine particulate removal efficiency of less than $2.5{\mu}m$, JIS standard fine sample was used and confirmed the removal efficiencies of 97% and 70~82% on the fine particulates of $1{\sim}2.5{\mu}m$ size range. For the size range of less than $1{\mu}m$, dust removal efficiency of manufactured metal filters significantly degraded with smaller particle size. Improving methods are proposed to overcome the limitations in applying to fine dust of less than $1{\mu}m$.

Fabrication of Film Bulk Acoustic Wave Filters with Ladder and Stacked Crystal Filter Types (Ladder 형과 SCF 형의 구조를 가지는 FBAR 필터의 제작)

  • ;;Mai Linh
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 한국해양정보통신학회 2003년도 추계종합학술대회
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    • pp.630-632
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    • 2003
  • In this paper, we present the fabrication and performance of FBAR filters with ladder and stacked crystal filter (SCF) types. The structure of the unit resonator in our work is the solidly mounted resonator (SMR) with W/SiO$_2$ multi-layer reflectors, the return loss of of which show -24dB at resonant frequency of -2.0GHz. The $K^2$eff, Q$_{s}$, and Q$_{p}$, indicating the performance of resonator were 3.24%, 6,363 and 6,749 and were calculated for the resonator with the resonance area of 21200${\mu}{\textrm}{m}$$^2$. Based on this unit resonator, FBAR filters with ladder and SCF types were fabricated and compared. The sizes of filters were 800$\times$2000(${\mu}{\textrm}{m}$$^2$) for the ladder type and 600$\times$500(${\mu}{\textrm}{m}$$^2$) for the SCF type.e..

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Efficiency of Livestock Farming Wastewater Treatment by Trickling Filters (撒水濾床法에 依한 畜産廢水의 處理效果에 관한 연구)

  • Ahu, Soo Mi
    • Journal of Environmental Health Sciences
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    • 제11권2호
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    • pp.17-27
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    • 1985
  • The objectives of this study is to examine efficiency of swinery wastewater treatment by trickling filters' pilot plant. The results of this study are as follows: 1. The characteristics of sample. The BOD$_5$ was from 2,450 to 2,880mg/l, COD(KMnO$_4$ acid method) was from 910 to 1,064mg/l, and SS was from 920 to 990mg/l. The pH of influent was from 7.3 to 7.6, and the temperature of water was from 17.0$\circ$C to 22.5$\circ$C. 2. For experiment by recirculation, the BODs removal efficiency is 65.2% at recirculation ratio (r)=0, and 70.7% at r=1. The ramoval efficiency of this study is higher than NRC formula of U.S.A.. The recirculation is not significant effect on removal efficiency. 3. For experiment by hydraulic load, the BOD$_5$ removal rate decreased from 73.1% at $3.1m^3/m^2\cdot d$ to 65.3% at $9.2m^3/m^2\cdot d$. The design formula of this study which shows the removal rate of soluble BOD is $Le/Li =10^{-0.24} D/Q^{0.24}$ (Q: hydraulic load, D: depth of filter). 4. For experiment by organic load, the BOD$_5$ removal rate is increased from 70.2% at $0.77kg/m^3\cdot d$ to 75.4% at $4.28kg/m^3\cdot d$. We can obtain the straight line y=0.749 x (y: removed BOD, x :applied BOD) by the least squares method. 5. We can know that trickling filters is strong with the hydraulic load and the organic matter shock load. Here, we can judge that trickling filters is a good method for the treatment of swinery wastewater which containing high concentrated organic matter.

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Evaluation of the Relationship between Filter Replacement and Filter Performance Change in Particulate Respirators (방진 마스크 필터 교체와 성능 변화의 상관성 조사)

  • Lee, Heonyung;Park, Jihoon;Yoon, Chungsik
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • 제27권4호
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    • pp.283-290
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    • 2017
  • Objectives: This study aimed to evaluate the relationship between filter replacement and filter performance change in particulate filters used in the workplace. Methods: Three types of particulate respirator filters are mainly used in the workplaces. These were tested against the filter performance safety certification standard for dust masks established by the Ministry of Employment and Labor(MoEL). Used filters were collected to test their performance, such as filter pressure drop, efficiency, and quality factors. All these factors were evaluated by a filter tester. To compare filter performance between used and new ones, the same kinds of new filters were also tested together under the same procedures. Results: A total of 270 used filters were collected for testing. The main reasons to replace the filters were difficulty in breathing(46.2%), dirty/odor influx(19.7%), and a combination of factors(26.7%). The pressure drop for two special class groups was significantly different(new filters: $20.72{\pm}3.33mmH_2O$; used filters: $24.70{\pm}5.26mmH_2O$, p<0.0001). In the case of penetration, new filter groups indicated $0.0032{\pm}0.0040%$, while that of the used filters was $0.0596{\pm}0.1187%$. The quality factor for the used filters($0.34{\pm}0.09$) significantly decreased compared to the new filters($0.53{\pm}0.08$) (p<0.0001). Conclusions: Filter performance including pressure drop, penetration, and the quality factor was evaluated and compared between new and used filters in the workplace. The results showed that general filter performance deteriorated more for change of pressure drop, penetration and the quality factor.

A Study on the High Temperature Filtration Performance Test of Low Density Ceramic Filters (저밀도 세라믹 필터의 고온 여과 성능시험에 관한 연구)

  • 이동섭;홍민선;최종인
    • Journal of Korean Society for Atmospheric Environment
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    • 제17권1호
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    • pp.75-84
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    • 2001
  • Hot gas filtration method via using ceramic filters is an evolving technology applicable to numerous industrial and air pollution control processes. Alumino silicate, organic and inorganic binders were the major raw materials in manufacturing ceramic filters. In this work, disc type ceramic filters(50$\phi$$\times$10t) were manufactured by vacuum forming processes using ceramic raw materials. The porosity and bulk density of disc type ceramic filers ranged from 86 to 89% and from 0.27 to 0.36 g/㎤, respectively. In this work disc type ceramic medium were tested utilizing coupon experimental apparatus. Disc type filters showed high collection efficiencies over 99.96% with Darchs law coefficients of 4.1$\times$10(sup)10~9.63$\times$10(sup)10/$m^2$ depending on mean pore sizes. In addition, filtration and detachment of ceramic filters turned out to be performed effectively using 10 cm/sec face velocity, 5 minutes filtration cycle, 100msec pulse jet valve opening time and 3 bar pulsing pressure.

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Fabrication and Measurement of Tunable Millimeter-wave Filters (주파수 가변형 밀리미터파 필터의 제작 및 측정)

  • Park, Jae-Hyoung;Kim, Hong-Teuk;Kwon, Young-Woo;Kim, Yong-Kweon
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • 제49권11호
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    • pp.627-634
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    • 2000
  • In this paper, new micromachined tunble bandpass filters for multi-band millimeter-wave telecommunication systems are proposed. Two types of mm-wave tunable filters are fabricated using micromachning technology and the responses of the filters are measured. One is two-pole lumped elements filter and the other two-pole resonators filter. Frequency tunability of the filter is achieved by changing the gap between a common CPW ground plate and the movable cantilever beam connected to the transmission line with the controllable renge of 2.5${\mu}m$. The deflection of cantilever beam is measured with the applied DC voltage. With the applied bias voltage from 0 to 50 V, the fabricated filters show 0.6 GHz(2.3%) at 26.6 GHz, and 0.8 GHz(2.5%) at 32 GHz center frequency shift for the lumped elements and resonators filter, respectively. The life time of the fabricated gold cantilever structure are tested.

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THE FILTERS OF THE ORDERED $\Gamma$-SEMIGROUPS

  • Kwon, Young-In
    • The Pure and Applied Mathematics
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    • 제4권2호
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    • pp.131-135
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    • 1997
  • We give the relation between the semilattice congruence N and the set of prime ideals of the ordered $\Gamma$-semigroup M.

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Tunable bragg filter of $Si_3N_4-SiO_2$ waveguide using thermooptic effect (열광학 효과를 이용한 $Si_3N_4-SiO_2$ 도파로 가변 브래그필터)

  • 이형종;정환재
    • Korean Journal of Optics and Photonics
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    • 제3권4호
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    • pp.244-251
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    • 1992
  • Buried Bragg filters of single mode $Si_{3}N_{4}$ rib waveguide with a cover layer of $SiO_{2}$ and grating at the interface of $Si_{3}N_{4}$ and $SiO_{2}$ are designed and fabricated. Etching of the grating on $Si_{3}N_{4}$ waveguide core by buffered HF showed uniform etching with good control up to 1 nm. This buried type of Bragg filters are immune to contamination of the surface of device. The mode index and bandwidth of filters are determined by measurements of the transmission spectrum of Bragg filters and compared with that of calculation. Waveguide Bragg filters loaded with the micro-heater of Cr film and the cladding of silicone rubber are made to control the Brag wavelength of the filter. As a result the filter wavelength of the device moved by 0.41 nm for 10 mA current to the shorter side of wavelength proportional to the square of the current.

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Standard calibration for H-α filter of DOAO 1m telescope

  • Ahn, Hojae;Pak, Soojong;Kang, Wonseok;Kim, Taewoo;Shim, Hyunjin
    • The Bulletin of The Korean Astronomical Society
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    • 제42권2호
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    • pp.89.1-89.1
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    • 2017
  • In this poster, we present standard calibration processes and results for photometry of $H-{\alpha}$ filter using broadband filters. We took data from a night in stable weather condition. And we derived parameters for band pass calibration including color terms. The corrected photometry results from broadband filters like V and R filters showed high correlation enough to replace instrumental $H-{\alpha}$ magnitude. We plan to extend these standardizing processes to another narrowband filters and flux calibration of narrowband filters from photometry of PNe.

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A Design of Lowpass Active Filter for ADLS Tx/Rx Stage (ADSL 송수신단용 저역통과 능동필터 설계)

  • Lee Geun-Ho
    • The Journal of the Acoustical Society of Korea
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    • 제24권1호
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    • pp.38-42
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    • 2005
  • CMOS analog lowpass filters using speech signal bandwidth for a Asymmetrical Digital Subscriver Line(ADSL) modem are presented. Designed active lowpass filters are composed of the CMOS complementary high-swing cascode stage which can increase transconductance of an active element. As a result, their cutoff frequency are 138kHz and 1,100kHz respectively. A low-voltage high-swing cascode integrator which improved on a gain and unit gain frequency used to design the filters. The designed filters are verified by HSPICE simulation with the $0.251{\mu}m\;CMOS\;n-well$ Parameter and a single 2.5V power supply.