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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society for Atmospheric Environment
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Korean Society for Atmospheric Environment
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Volume & Issues
Volume 17, Issue 5 - Oct 2001
Volume 17, Issue 4 - Aug 2001
Volume 17, Issue E1 - Apr 2001
Volume 17, Issue 3 - Mar 2001
Volume 17, Issue 2 - Feb 2001
Volume 17, Issue 6 - Jan 2001
Volume 17, Issue 1 - Jan 2001
Volume 7, Issue 6 - 00 2001
Volume 7, Issue 5 - 00 2001
Volume 7, Issue 4 - 00 2001
Volume 17, Issue E4 - 00 2001
Volume 17, Issue E3 - 00 2001
Volume 17, Issue E2 - 00 2001
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Catalytic Partial Oxidation of Methane to Methanol
최우진 ; 박지영 ; 김명수 ; 박홍수 ; 엄현식 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 187~187
The partial oxidation of methane to produce methanol was investigated with various oxide catalysts. The reaction was carried out using a pyrex-lined fixed bed reactor at 450 ~ 480 ℃ and 20 ~ 46 bar, while changing the flow rate and feed gas ratio. The adsorption and desorption characteristics of oxygen were examined with an O2-TPD experiment. Bi-Cs-Mg-Cu-Mo catalyst was found to be the most suitable for methanol synthesis. It appeared that a catalyst that can easily provide lattice oxygen is more suitable for methanol synthesis. The methane conversion and methanol selectivity increased with the temperature. The methane conversion increased with the oxygen concentration, while the methanol selectivity decreased with increasing oxygen concentration. The feed flow rate did not exhibit any significant effects on methane conversion and methanol selectivity.
Selective Catalytic Oxidation of Volatile Organic Solvent Mixtures
이성범 ; 정기원 ; 홍인권 ; 김형진 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 193~193
The selective catalytic oxidation of volatile organic solvents (benzene, toluene, ethylbenzene, xylene, and styrene) and their mixtures was studied on a 0.5% Pt / γ-Al2O3 catalyst at temperatures ranging from 160 ~ 350 ℃. An approach based on the two-stage redox model was used to analyze the results. The deep conversion of the aromatic solvents increased as the inlet concentration decreased and the reaction temperature increased. The reactivity increased in order benzene > toluene > ethylbenzene > xylene > styrene. The kinetic parameters of the multicomponent model were independently evaluated from single compound oxidation experiments. In a mixture, remarkable effects on the reaction rate and selectivity were observed; the strongest inhibition effect was shown by styrene and increased in the reverse to that of reactivity. The inhibition effect increased in order styrene > toluene > benzene. The selective oxidation revealed that there was a competition between the two reactants for the oxidized catalyst. Therefore, proper operating conditions in a commercial process must take account of the inhibition effect.
The Effect of Carbon Black on PTC Characteristics of Conductive Polyethlene/Carbon Black Composite
강필현 ; 노영창 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 199~199
The effect of the carbon black structure on the PTC(positive temperature coefficient) characteristics of a conductive high density polyethylene/carbon black (HDPE/CB) composite was investigated. The HDPE/CB composite was irradiated with gamma rays to a dosage of 50 kGy, 100 kGy and 150 kGy for the purpose of reducing the NTC (negative temperature coefficient) of the conductive composite. It was found that the PTC intensity depended on the particle size, surface area and loading of the carbon black. The PTC intensity of HDPE/CB increased as the loading and surface area of the carbon black decreased. The electrical reproducibility of HDPE/CB was improved by radiation crosslinking compared with the unirradiated compound. The absence of the NTC effect in the crosslinked CB-filled polymer composites was related to an increase in the viscosity of the polymer matrix, thereby leading to a significant reduction in the mobility of the CB particles in the composites.
Mini-Pilot Scale Production of Homopolymer and Block Copolymer by Anionic Polymerization
이형우 ; 박용호 ; 강신춘 ; 노시태 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 204~204
In order to obtain a large amount of polymer samples with a well-controlled molecular weight and polydispersity index, a bench scale reactor system for anionic polymerization was built instead of the traditional break-seal method. Homopolymers were successfully prepared from non-polar monomers in amounts of 40 ~ 350 g with well-defined structures. The major process variables were found to be the type of initiator, monomer concentration. and the volume of the reaction mixture. When a higher monomer concentration or larger reaction mixture volume was used, the removal of reaction heat became critical. In the case of a polar monomer, close control of the anionic polymerization was required to obtain a lower PDI. In the preparation of a diene-acryl block copolymer, it was found that the thorough removal of any impurities from the second monomer was critical for suppressing the generation of a homopolymer.
Cure Characteristics and Dynamic Mechanical Properties of Acrylic Rubber and Epoxidized Natural Rubber Blend
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 212~212
With employment of ACM (acrylic rubber) and ENR (epoxidized natural rubber), the rubber and chemical additives were Compounded by mechanical method using a Banbury mixer and an open 2 roll mill. Then rubber vulcanizates were prepared by compression mold, and cure characteristics (cure behavior, scorch time, and optimum cure time), maximum torque value, Mooney viscosity, and dynamic mechanical properties of the test specimens were measured. The torque value of rubber mix was obtained with a maximum at ACM/ENR (=25/75) blend. Results determined from a Rheovibron showed two glass transitions (T(g)) for ACM/ENR (=75/25) indicative of the immiscible nature of the blend. However, in ACM/ENR (=25/75) blend, a single T(g) indicating miscibility was obtained.
Damping Characteristics of Polyaniline-Based Electrorheological Fluid
김지우 ; 최형진 ; 이호균 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 218~218
Polyaniline (PANI) particles were synthesized by the chemical oxidation of aniline in acidic media, then the optimum conductivities in a semiconductive range for electrorheological (ER) application were achieved by adjusting the pH of an aqueous solution containing PANI particles. A semi-active ER damper filled with the PANI-based ER fluid was then investigated under different electric field strengths. The damping forces measured could be controlled by tuning the applied electric field for different piston velocities.
Preparation and Properties of Polyurethane Modified with Polyorganosiloxane Sealant
한미선 ; 강두완 ; 강호종 ; 이상문 ; 김영민 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 223~223
α,ω-Trimethoxysilyl polyurethane modified with polyorganosiloxane JUMPS) sealant was prepared by adding additives, such as plasticizer, crosslinking agent, and viscosity increasing agent, to α,ω-trimethoxysilyl polyurethane modified with polyorganosiloxane hybrid elastomer at room temperature under nitrogen atmosphere. The TUMPS hybrid elastomer was crosslinked by the sol-gel reaction of methoxy group of TUMPS with hydroxyl group in the building stone and moisture of the air. It was found that TUMPS sealant exhibited more stable rheological and sealant properties than those of TUMPS hybrid elastomer. The shrinkage rate of TUMPS sealant was 5.82-6.0%, and skin over time was about 40 min. Alkaline resistance showed good characteristics for 15 days, slump was about 4.0-4.3 min, and oil content, as the diameter soaked oil from wetted filter paper was 1-2 min after 7 days.
Numerical Simulation of Separation of Cobalt and Nickel Using Hollow Fiber Supported Liqiud Membrane (HFSLM)
최정우 ; 조경상 ; 오병곤 ; 윤인주 ; 정진기 ; 박수용 ; 이원홍 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 230~230
The selective separation of cobalt ion from a feed solution containing cobalt and nickel ions using a hollow fiber supported liquid membrane (HFSLM) was analyzed to evaluate the design parameters. A mathematical model for the simultaneous permeation of cobalt and nickel ions was developed and model equations were solved using the orthogonal collocation technique. The prediction by the model was in good agreement with the experimental data obtained using the HFSLM. The effect of various operating conditions, such as pH in the feed phase, carrier composition, module thickness, and module length, was analyzed. The optimum operating conditions with the highest flux and separation factor of cobalt ion were determined based on the simulation results.
Formation of Zeolite A Film on Metal Substrates by Microwave Heating
백동률 ; 왕은연 ; 설용건 ; 구기갑 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 241~241
Microwave heating was applied to the formation of zeolite A films on copper (Cu) and stainless steel (SUS) substrates. It was confirmed that crystallization time by microwave heating was Much smaller than that by conventional heating due to the rapid dissolution of gel, nucleation and growth of zeolite crystals. It was found that the film formation was primarily influenced by surface properties of the metal substrates: a dense film of zeolite A crystals with the size of about 0.3 ~ 1.0 μm was formed on Cu substrates. However, no layer-like zeolite film was formed on the SUS substrate. Nucleation of zeolite A crystals on metal substrates was also found to be strongly affected by the heating method and pretreatment of synthesis solution.
Fouling Steps in the Microfiltration of Kaolin Suspensions
정근영 ; 장규만 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 250~250
Kaolin filtration experiments were carried out using a dead-end Amicon filtration cell with 0.2 μm polytetrafluoroethylene membrane as a function of operating pressure, kaolin concentration and stirring speed. Also, the intrinsic membrane. fouling and cake laver resistances were measured and calculated, respectively. For the system the cake layer resistance was dominant factor on permeate flux decline and increased with operating pressure and kaolin concentration. The experimental data of permeate fluxes were fitted by the constant pressure filtration models in order to investigate fouling steps. The cake filtration model was the most suitable for the stirring speed of higher than 300 rpm or 0.05 wt% kaolin solution. However, in the cases of higher kaolin concentration and lower stirring speed, the cake filtration model superimposed with standard pore blocking model after initial 60 to 90 minutes correlated well with the experimental data.
Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by MCM-41-Supported Ephedrine
김상한 ; 양호준 ; 정성택 ; 진명종 ;
Journal of Korean Society for Atmospheric Environment, volume 7, issue 4, 2001, Pages 259~259
MCM-41 silica-supported ephedrine was prepared and utilized as an asymmetric catalyst for enantioselective addition of diethylzinc reagent to aldehyde. The MCM-supported ephedrine led to much faster reaction and higher asymmetric induction than silica gel-supported ephedrine. Highly ordered MCM-41 silica was found to be better inorganic support for the catalytic system than amorphous silica gel.