• 한국산업보건학회지
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• 제3권1호
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• pp.37-53
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• 1993

The polynuclear hydrocarbons (PAHs) emitted from coke oven standpipe were sampled using three sampling systems, including glass fiber filter+silver membrane filter, glass fiber filter+silver membrane filter+XAD-2 adsorbent tube, PTFE membrane filter+XAD-2 adsorbent tube, extracted by methylene chloride and analysed by gas chromathography using flame ionization detector. The results of this study were as follows. 1. Because the amounts of coke oven emissions(COE) were large, the analyses of PAHs were simple and possible without evaporation and concentration. Although the generation of COE was high during early stage of coking, the airborne concentration of PAHs was low and increased during late coking. 2. The contents of PAHs in COE were 1.35-2.81%. 3. The index components of PAHs were fluoranthene and pyrene. Their correlation coefficient to total PAHs were 0.96, 0.95, respectively. 4. The particulate PAHs were sampled by filter and gaseous PAHs by adsorbent tube. The collection efficiency of glass fiber filter+silver membrane filter was 20% of total amount sampled by filters+adsorbent and PTFE membrane filter 50%. Adsorbent tube must be attached to the filter to collect light and small PAH components. 5. The generation of acenaphthene and indeno (1,2,3-cd) pyrene were low and concentrations of fluorene and anthracene were $20-40ug/m^3$ throughout coking time. Other PAH eoncentrations were sometimes high. The generation of PAHs was low at 4-6 hours of coking time. The gaseous PAHs were generated earlier than particulate PAHs.

• 한국정밀공학회지
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• 제21권9호
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• pp.111-118
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• 2004

The automatic assembly system of micro optical filter is a key technology in the development of optical modules with high functionality. In order to develop an automatic assembly system of optical fiber and filter, we have firstly developed the system and program capable of characterization of 30${\mu}m$-thick film filters as well as conventional optical filters. Moreover, we have carried out the characterization of optical filter using the developed system and program, and compared experimental results with by conventional handwork. The measurement of optical filters using the present system is faster, more precise and more reliable than those based on the conventional handwork.

• Journal of Animal Science and Technology
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• 제46권5호
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• pp.763-772
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• 2004

Neocallimastix frontalis SA에게 에너지원으로 filter paper 또는 볏짚만을 공급하여 반추위 곰팡이를 배양하는 동안 섬유소 분해 양상을 현미경으로 관찰하고 cellulase와 xylanase 생산에 미치는 영향을 비교하였다. 혐기성 반추위 곰팡이를 접종한 후 filter paper를 광학 현미경으로 관찰하였을 때 filter paper의 표면과 모서리에 유주자의 부착, 포자낭의 발달 그리고 복잡한 그물망의 균사 엽상체의 형성이 관찰되었으며, 배양 7일 후에는 filter paper의 소화 그리고 섬유사의 결착성 및 견고성의 감소 현상이 나타났다. 또한 분쇄한 볏짚 표면에서도 미성숙 및 성숙한 포자낭들이 관찰되었으며, 일반적으로 이들 균사들은 볏짚의 부스러진 부분이나 잘리어진 모서리에서 많이 발견되었다. cellulase와 xylanase는 배양기간 동안 filter paper와 볏짚 기질 모두에서 빠르게 그 농도가 증가하였으며, 볏짚 첨가시에 비해 filter paper 첨가시가 더 높은 경향을 보였다. 특히 두 가질간의 cellulase와 xylanase 효소 활성은 각각 48 그리고 96시간 배양 이후에 큰 차이를 보였다(P<0.05). 따라서 filter paper는 복합 구조를 갖는 볏짚에 비하여 cellulase와 xylanase 생산을 위한 더 좋은 유도 물질임을 발견하였다. 이상의 결과들을 N. frontalis에 대한 에너지원으로서 단일 복합체인 filter paper가 복합 구조의 볏짚에 비해 더 우수하였으며, 물리적 및 화학적으로 섬유소를 분해하는 혐기성 반추위 곰팡이라 할 지라도, 리그닌화된 견고한 섬유소 구조를 파괴시킬 수 있는 물리적 처리는 반추위 곰팡이의 분해 작용 및 성장에 도움을 줄 수 있음을 시사한다.

• 상하수도학회지
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• 제31권2호
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• pp.125-139
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• 2017

In this paper, the performance of a synthetic fiber filter aimed at high-speed operation and dosed with different coagulants or filter aids was investigated. Without a coagulant, the filter efficiency was about 62% which was greatly enhanced when three types of coagulants namely PAC, Alum, and $FeCl_3$ were used. Among the coagulants tested, PAC was the most effective, giving 91% filter efficiency, followed by Alum with 90%, and $FeCl_3$ with 78%. PAC worked effectively at a very small range of dose, but Alum was relatively effective in a wide range of concentration. Compared with PAC and Alum, $FeCl_3$ provided more or less contant efficiency regardless of its dose but gave the poorest filter efficiency. Moreover, as the inflow turbidity increased, headloss increased and the efficiency decreased at any dose and type of coagulant. The headloss recorded in this particular synthetic fiber filter is not significant as compared to that observed in typical granular filters. The recovery of solids estimated after filter cleaning was about 80% for both PAC and Alum, but poorer at 72% in the case of $FeCl_3$ due to the heavy and large floc characteristics. The recurrence of filter efficiency verified through repetitive filter runs was found to be satisfactory.

• 조명전기설비학회논문지
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• 제30권2호
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• pp.11-19
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• 2016

By incorporating a polarization-diversity loop configuration, we have demonstrated the inline switching of transmission and reflection spectra of one of two short-period fiber gratings (SPFGs) with different resonance wavelengths without reconfiguring the filter structure. The proposed filtering apparatus consists of a fiber-pigtailed polarization beam splitter, two SPFGs, and three quarter-wave plates (QWPs). The proposed filter can independently choose the transmission or reflection spectrum of each SPFG through the appropriate adjustment of the orientation angles of the QWPs within the filter without additional optical switches and couplers. The average insertion loss, band rejection ratio, and side-mode suppression ratio of the fabricated filter were measured as ~4.59, ~17.88, and ~19.67dB, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.265-265
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• 2010

일반적으로 중금속이나 질산성 질소와 같은 이온성 물질들은 사람의 건강이나 생태계에 좋지 않은 영향을 미칠 수 있다. 이들 오염물질들은 그 종류에 따라 건강에 피해를 주는 정도에 차이가 있지만 안전한 생태환경을 유지하기 위해서는 이들 물질들을 효과적으로 처리할 수 있는 필터가 필요하다. 전극 필터에 최대한 많은 이온들을 흡착시키기 위해서는 전극의 비표면적을 높이는 것이 매우 중요하다. Metal Fiber Filter의 제작과 제작된 Filter의 전기적 특성과 비표면적 향상, 고정성 및 통전성, 축전용량과 전기흡착 및 탈착 경향을 관찰하기 위해 3전극 시스템을 이용하여 Cyclic Voltammetry(CV)와 Chrono-amperometry(CA)를 측정하고 표면의 기공 구조를 관찰하기 위해 주사전자현미경 (SEM;Scanning Electron Microscope)을 이용하여 전극에 생성된 미세 기공의 크기 및 크기 분포를 측정한다. 또한 제작된 Filter 전극을 이용하여 전기장 하에서 수질 속에 있는 질산성이온의 선택적 제거 효율을 측정하여 보고, 측정된 데이터 값을 통해 Metal Fiber Filter의 전기적 특성과 중금속이나 질산성 이온 물질들을 선택적으로 제거할 수 있는 Filter 전극 설계 근거를 제시하고자 한다.

• 상하수도학회지
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• 제20권2호
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• pp.235-244
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• 2006

A PCF(Pore Controllable Fiber Filter) process was applied as a pretreatment of water treatment for reduction of turbidity. The experimental results obtained from the PCF showed that the removal efficiency of turbidity without coagulation was around over 70 percent. However, the removal efficiency of turbidity by the coagulation-PCF process was high as much as over 95%. Thus, the coagulation pretreatment was required for the better operation of the PCF. The SEM (Scanning Electron Microscope) images of fiber before and after filtration showed that the filtration mechanism of PCF filter is both controlling attachment mechanism and Sieving mechanism through fiber pore. For the coagulation-PCF process, optimum dosage of coagulant was needed for the economical operation, and for this, determining the optimum dosage by using a filter column test. Also only 16mg/L of alum was used to obtain high algae removal efficiency over 90%. Therefore, it can be concluded that coagulation-PCF process is very effective pretreatment process for algae removal.

• 전자공학회논문지A
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• 제32A권8호
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• pp.133-139
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• 1995

In this paper, the frequency separation locking and interval stabilization of 4-channel DFB-LDs have been demonstrated using a fiber Fabry-Perot filter with an free spectral range of 100GHz. Frequency fluctuation and locking range of each channel were appeared to be within 15MHz and over 12GHz, respectively. Back-reflection curve from the fiber Fabry-Perot filter was used for the extraction of an error signal in order to increase the number of accomodable channels and extinction ratio.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2000년도 추계학술대회 논문집
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• pp.427-428
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• 2000

공기 여과 장비에 주로 쓰이는 섬유층 여과기(fibrous filter)는 다양한 장비에 널리 쓰이고 있다. 섬유층 여과기는 이를 구성하는 섬유(fiber)의 직경, 표면 조도, 그리고 이들로 해서 나타나는 공극률, 하전여부, 등 여러 가지 필터의 특성에 따라 다양한 포집양상(Deposition Morphology)을 보인다. 제조 공정에 따라 달라지는 특성을 가진 필터는 여과 과정을 거치면서 입자가 퇴적되고 압력강하가 증가하여 필터의 수명이 다하게 된다. (중략)

• 한국수산과학회지
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• 제40권2호
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• pp.73-78
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• 2007

The suitability of a flexible fiber filter for removing suspended solid (SS) in a recirculating aquaculture system was evaluated. This study focused on variation in the performance with a change in filtering time, influent water quality, and filtering mode duration. The particle distribution diagram of the filter effluent showed that the number of particles bigger than $5-8{\mu}m$ decreased dramatically, and the removal efficiency exceeded 80%. Although the removal efficiencies of SS and chemical oxygen demand (COD) were dependent on the quality of the influent, the SS and COD concentrations of the effluent were not affected by the influent concentrations. This was despite the deterioration if water quality after feeding in the rearing tank. The performance of the filter was not affected by the filtering mode duration, feeding conditions, or filtering time. The SS concentration and turbidity of the recirculating-type rearing tank were 30% and 50% lower, respectively, than of the a non-recirculating-type rearing tank under the same operating conditions. The flexible fiber filter was applicable to a recirculating aquaculture system that uses plenty of seawater, based on its low filtering resistance $(2kg_f/cm^2)$, high flux $(330m^3/m^2/hr)$, and high fine particle removal efficiency (80%, $5-8{\mu}m$).