• 한국재료학회지
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• 제27권5호
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• pp.270-275
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• 2017

Inorganic phosphors based on $ZrO_2:Eu^{3+}$ nanoparticles were synthesized by a salt-assisted ultrasonic spray pyrolysis process that is suitable for industrially-scalable production because of its continuous nature and because it does not require expensive precursors, long reaction time, physical templates or surfactant. This facile process results in the formation of tiny, highly crystalline spherical nanoparticles without hard agglomeration. The powder X-ray diffraction patterns of the $ZrO_2:Eu^{3+}$ (1-20 mol%) confirmed the body centered tetragonal phase. The average particle size, estimated from the Scherrer equation and from TEM images, was found to be approximately 11 nm. Photoluminescence (PL) emission was recorded under 266 nm excitation and shows an intense emission peak at 607 nm, along with other emission peaks at 580, 592 and 632 nm which are indicated in red.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2000년도 추계학술대회
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• pp.39-41
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• 2000

Newly modified spray Pyrolysis system was developed to Produce ultra Pure and fine Powder by spray Pyrolysis Process. In this system, raw material solution was effectively atomized and sprayed into the reaction furnace. Also, thermal decomposition process fully completed in the three zone reaction furnace, and produced powder was effectively collected. A technology to reduce impurities in complex acid solution below 20ppm was also developed. The characteristics of produced powder were studied by changing the reaction conditions such as reaction temperature, the injection velocity of the solution and air, nozzle tip size and concentration of solution. The morphology of powder had spherical shape under the most experimental conditions, and the composition and the particle size distribution were almost uniform. Under the most experimental conditions average particle size of most produced powder was below 100nm.

• 한국추진공학회지
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• 제25권4호
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• pp.36-42
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• 2021

본 연구에서는 리오셀 섬유를 사용하여 연속식 흑연직물을 제조함에 있어, 리오셀 섬유에 phosphoric acid, ammonium phosphate, diammonium hydrogen, triammonium phosphate의 인계난연제를 처리 후 열중량, 푸리에변환적외선분광, C-핵자기공명분광, X-선 회절, 중량 분석을 통해 나타나는 물리적, 화학적 구조 변화에 대하여 고찰하였다. 인계난연제에 의한 열적 거동을 분석을 통해 내염화 공정의 온도, 가스, 처리시간 등에 대한 조건을 설정하였다. 연속식 내염화, 탄화, 흑연화 공정을 통해 인장강도 1,007.19±11.47 N/5 cm와 수율 25.3%의 흑연직물을 제조하였다.

• 한국재료학회지
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• 제14권8호
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• pp.600-606
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• 2004

$Zn_{2}SiO_{4}:Mn$ phosphor particles were prepared by a flame spray pyrolysis method. It has been generally known that the high-temperature flame enables fast drying and decomposition of droplets. In the present investigation, the morphology and luminescent property of $Zn_{2}SiO_{4}:Mn$ phosphor were controlled in a severe flame preparation condition. The particle formation in the flame spray pyrolysis process was achieved by the droplet-to-particle conversion without any evaporation of precursors, which made it possible to obtain spherical $Zn_{2}SiO_{4}:Mn$ particles of a pure phase from a droplet. Using colloidal solutions wherein dispersed nano-sized silica particles were adopted as a silicon precursor. $Zn_{2}SiO_{4}:Mn$ particles with spherical shape and filled morphology were prepared and the spherical morphology was maintained even after the high-temperature heat treatment, which is necessary to increase the photoluminescence intensity. The $Zn_{2}SiO_{4}:Mn$ particles with spherical shape, which were prepared by the flame spray pyrolysis and posttreated at $1150^{\circ}C$, showed good luminescent characteristics under vacuum ultraviolet (VUV) excitation.

• Journal of Biosystems Engineering
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• 제34권1호
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• pp.44-49
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• 2009

This study was conducted to investigate the pyrolysis characteristics of switchgrass using TGA-FTIR instrument. Switchgrass is a high yielding perennial grass that has been designated as a potential energy crop, because of its high energy value. Ground switchgrass were pyrolysed at different heating rates of 10, 20, 30, and $40^{\circ}C/min$ in a TGA-FTIR instrument. The thermal decomposition characteristics of switchgrass were analyzed, and the gases volatilized during the experiment were identified. The thermal decomposition of switchgrass started at approximately $220^{\circ}C$, followed by a major loss of weight, where the main volatilization occurred, and the thermal decomposition was essentially completed by $430^{\circ}C$. The pyrolysis process was found to compose of four stages; moisture evaporation, hemicellulose decomposition, cellulose decomposition, and lignin degradation. The peak temperatures for hemicellulose decomposition ($306^{\circ}C$ to $327^{\circ}C$) and cellulose decomposition ($351^{\circ}C$ to $369^{\circ}C$) were increased with greater heating rates. FTIR analysis showed that the following gases were released during the pyrolysis of switchgrass; $CO_2$, CO, $CH_4$, $NH_3$, COS, $C_{2}H_{4}$, and some acetic acid. The most gas species were released at low temperature from 310 to $380^{\circ}C$, which was corresponding well with the observation of thermal decomposition.

• 자원리싸이클링
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• 제13권1호
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• pp.3-13
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• 2004

바이오매스의 이용은 과거부터 지속되어 왔지만 최근 들어 새로운 대체에너지로의 활용이라는 측면에서 집중적인 연구가 시도되고 있다. 바이오매스를 이용하는 방법으로서의 fast pyrolysis는 다른 방법들보다 고부가가치의 화학물질을 생성할 수 있다는 점에서 크게 주목을 받고 있다. 이 리뷰 논문은 현재 fast pyrolysis를 바이오매스 전환 공정으로 이용하고 있는 실례를 선보이고 그 공정에서 생산되는 생성물인 bio-oil의 특성을 소개하고 있다.

• 대한환경공학회지
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• 제22권1호
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• pp.133-139
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• 2000

리그닌의 열분해반응 후 발생하는 잔류고형물을 활용해보고자 $ZnCl_2$로 활성화하여 활성탄을 제조하였다. 공정변수로 설정한 활성화 온도, 활성화 시간 및 활성화제의 첨가량 등이 활성탄의 세공구조와 비표면적에 미치는 영향을 조사하여 최적 활성화 조건을 구하였다. 리그닌의 열분해 잔류고형물에 활성화제인 염화아연을 300wt% 첨가한 것을 질소분위기에서 $1000^{\circ}C$로 1시간 동안 활성화시켰을 때 비교적 높은 비표면적과 흡착능을 가지면서 세공구조가 잘 발달된 활성탄을 제조할 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권2호
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• pp.41-49
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• 2022

To abate the environmental burdens arising from CO₂ emissions, biochar offers a strategic means to sequester carbons due to its recalcitrant nature. Also, biochar has a great potential for the use as carbon-based adsorbent because it is a porous material. As such, developing the surface properties of biochar increases a chance to produce biochar with great adsorption performance. Given that biochar is a byproduct in biomass pyrolysis, characteristics of biochar are contingent on pyrolysis operating parameters. In this respect, this work focused on the investigation of surface properties of biochar by controlling temperature and reaction medium in pyrolysis of pine sawdust as case study. In particular, CO₂ was used as reaction medium in pyrolysis process. According to pyrolytic temperature, the surface properties of biochar were indeed developed by CO₂. The biochar engineered by CO₂ showed the improved capability on CO₂ sorption. In addition, CO₂ has an effect on energy recovery by enhancing syngas production. Thus, this study offers the functionality of CO₂ for converting biomass into engineered biochar as carbon-based adsorbent for CO₂ sorption while recovering energy as syngas.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.409-412
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• 2001

The high purity manganese oxides were made from the dust, generated in AOD process that produces a medium-low carbon ferromanganese and collected in the bag filter. Manganese oxide content in the dust was about 90%, and its phase was confirmed as Mn₃O₄. In the extraction of manganese, because of remaining amorphous MnO₂, the dust was reduced to MnO by roasting with charcoal. The pulp density of the reduced dust can control pH of the solution more than 4 and then Fe ion is precipitated to a ferric hydroxide. Because a ferric hydroxide co precipitates with Si ion etc, Fe, Si ion was removed f개m the solution. Heating made water to be volatized and nitrates was left in reactor Then nitrates were a liquid state and stirring was possible. Among the nitrates in reactor, only the manganese nitrate which have the lowest pyrolysis temperature pyrolyzed into β-MnO₂powder and NO₂(g) at the temperature less than 200℃. When the pyrolysis of manganese nitrate has been completed about 90%, injection of water stopped the pyrolysis. Nitrates of impurity dissolved and the spherical high purity β-MnO₂powders were obtained by filtering and washing. Mn₂O₃or Mn₃O₄ powder could be manufactured from β-MnO₂powder by controlling the heating temperature. Lastly, a manufactured manganese oxide particle has 99.97% purity.

• 청정기술
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• 제26권1호
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• pp.79-87
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• 2020

The bio-oil produced from the fast pyrolysis of lignocellulosic biomass contains a high amount of oxygenates, causing variation in the properties of bio-oil, such as instability, high acidity, and low heating value, reducing the quality of the bio-oil. Consequently, an upgrading process should be recommended ensuring that these bio-oils are widely used as fuel sources. Catalytic fast pyrolysis has attracted a great deal of attention as a promising method for producing upgraded bio-oil from biomass feedstock. In this study, the fast pyrolysis of tulip tree was performed in a bubbling fluidized-bed reactor under different reaction temperatures, with and without catalysts, to investigate the effects of pyrolysis temperature and catalysts on product yield and bio-oil quality. The system used silica sand, ferric oxides (Fe₂O₃ and Fe₃O₄), and H-ZSM-5 as the fluidized-bed material and nitrogen as the fluidizing medium. The liquid yield reached the highest value of 49.96 wt% at 450 ℃, using Fe₂O₃ catalyst, compared to 48.45 wt% for H-ZSM-5, 47.57 wt% for Fe₃O₄ and 49.03 wt% with sand. Catalysts rejected oxygen mostly as water and produced a lower amount of CO and CO₂, but a higher amount of H₂ and hydrocarbon gases. The catalytic fast pyrolysis showed a high ratio of H₂/CO than sand as a bed material.