• 전기학회논문지
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• 제61권2호
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• pp.339-341
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• 2012

The high Tc superconductor of YBCO system with the nominal composition of precursor was prepared from mixed powders of $Y_2O_3$, $BaCO_3$, CuO and $TiO_2$ by the thermal pyrolysis method. The effect of $TiO_2$ doping to Y based ceramics superconductors fabricated by the thermal pyrolysis reaction, to investigate the effect of the dopant on the superconductivity. The voltage appearing across the field-cooled HTS sample increased with external magnetic field. The improvement of critical current property as well as the mechanical property is important for the application. The improvement of the critical current can be achieved by forming the nano size defect working as a flux pining center inside the superconductor. We simply added $TiO_2$ to starting materials to dope $TiO_2$ and observed an increase in the trapped field and the critical current density up to at least 5 wt % $TiO_2$. The $TiO_2$ was converted to fine $BaTiO_3$ particles which were trapped in YBCO matrix during the sintering process. We observed a peak effect of Jc that can be attributed to $TiO_2$ doping and results suggest that introducing a proper amount of pinning centers can significantly enhance current density.

• 분석과학
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• 제5권4호
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• pp.373-379
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• 1992

피난의 열 이성화반응 생성물에 관한 연구를 위하여 열분해 조건을 가스크로마토그래피와 질량분석기에 장치된 전기로형 및 curie-point 열분해기를 이용하여 실험을 행하였다. 그 결과, 최적 조건하에서 전기로형보다는 curie-point 열분해기에 의해서 피난으로부터 주 이성화 생성물인 citronellen (70%)을 얻었다. 본 연구에서 열분해 최적 조건은 $590^{\circ}C$, 4 Sec이고, 확인된 열분해 주 생성물은 citronellene, m-Menth-6-ene, m-Menth-1-ene, 1-Methyl-4(1-methyl-ethylidene) cyclohexane이었다.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.547-552
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• 2007

This study examined the thermal reactions of 2,4-dibromophenol (diBP), 2,6-diBP and 2,4,6-triBP. The products obtained under pyrolytic conditions were analyzed by gas chromatography/mass spectrometry (GC/MS). 2,7-dibromodibenzo-p-dioxin (diBDD) was the major compound produced from the thermal reaction of 2,4-diBP. In addition, monoBDD and triBDDs were obtained through a process of debromination and bromination, respectively. The pyrolysis of 2,6-diBP and 2,4,6-triBP produced two major brominated dioxin isomers through direct condensation and a Smiles rearrangement. The two ortho-Brs in 2,6-diBP and 2,4,6-triBP mainly led to the production of dioxins, whereas in addition to 2,7-diBDD, 2,4-diBP produced two furans as minor products, 2,8-dibromodibenzofuran (diBDF) and 2,4,8-triBDF, through the intermediate dihydroxybiphenyl (DOHB). The maximum yield of the major dioxins was obtained at 400 oC, and decomposition by debromination at 500 oC resulted in less substituted bromodioxins.

• 한국세라믹학회지
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• 제49권4호
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• pp.279-286
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• 2012

Microstructure tailoring of filler loaded preceramic polymer systems offers a high potential for property improvement of Si-based ceramics and composites. Advancements in manufacturing of bulk materials by controlling microstructure evolution during thermal induced polymer-ceramic transforma-tion and polymer-filler reactions will be presented. Rate controlled pyrolysis, multilayer gradient laminate design and surface modification by gas solid reaction are demonstrated to yield ceramic components of high fractional density and superior mechanical properties. Emerging fields of applications are presented.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1499-1502
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• 2005

Dense $BaMgAl_{10}O_{17}:Eu^{2+}$ phosphor particles with a spherical shape have been synthesized through spray pyrolysis method using basic aluminum nitrate precursor as a spray solution. This $BaMgAl_{10}O_{17}:Eu^{2+}$ particles prepared by the spray pyrolysis have shown the stronger emission intensity compared to the commercially-available $BaMgAl_{10}O_{17}:Eu^{2+}$. However, thermal stability of the BAM:Eu b lue phosphor is very poor due to changing from $Eu^{2+}$ to $Eu^{3+}$ at the thermal process, so brightness of the phosphor decreases. To improve the thermal stability of the dense BAM:Eu phosphor, the spherical BAM:Eu particles were coated with pure $BaMgAl_{10}O_{17}$ layer using the hydrolysis reaction in a solution system. The synthesized powders were characterized by XRD, SEM and PL. On the other hand, the emission properties of the BAM:Eu phosphors coated with $BaMgAl_{10}O_{17}$ layer before and after thermal treatment at $500^{\circ}C$ for 30 min were estimated under VUV excitation. The brightness of the coated phosphor was higher than that of the uncoated phosphor. Also, the coating thickness of BAM layer in the BAM:Eu particles was optimized.

• 한국기후변화학회지
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• 제8권3호
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• pp.231-237
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• 2017

In this study, the $N_2O$ emission factor of the facility was developed by measuring the kiln type pyrolysis melting facility. This used PAS (Photoacoustic Spectroscopy) method and measured the $N_2O$ emission concentration. From March 2016 to April 2016, it was measured over a total of two times and $N_2O$ concentrations were measured continuously for 24 hours using a 24 hour continuous measuring instrument (LSE-4405). The measured $N_2O$ emission concentration of the pyrolysis melting facility was 0.263 ppm on average and the emission concentration distribution in the range of 0.013~0.733 ppm was obtained. Therefore, the $N_2O$ emission factor of the kiln-type pyrolysis melting facility was estimated to be $0.829gN_2O/ton$-Waste. As a result of comparing the $N_2O$ emission factor of the thermal kiln type pyrolysis melting facility and the previous study, previous studies were about 18 times higher. It is estimated that this is due to the difference of furnace temperature, oxygen concentration and denitrification facilities. It is considered that the study of the emission factor of pyrolysis melting facility is an important factor in improving the credibility of greenhouse gas inventory in waste incineration sector.

• 항공우주시스템공학회지
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• 제1권2호
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• pp.37-42
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• 2007

This paper proposes a numerical modeling approach to simulate the hybrid combustion phenomena. From the physical understandings of hybrid combustion, the computational domain was separated into three regions: the solid fuel, gas phase reactive flow, and the interface between solid and fluid. Moreover, for the accurate calculation, computational grids for these regions was generated at every time step considering the instantaneous moving interface which are governed by the balance equations using thermal pyrolysis. In the domain of reactive flow, by virtue of diffusion flame structure, turbulent combustion modeling was introduced using either mixture fraction approach or mean reaction rate approach.

• 환경위생공학
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• 제15권4호
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• pp.98-104
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• 2000

Commercial rubber(IR, NR, BR), SBR, and tire were degraded by thermal degradation process. The oil yield of rubbers and tire ranges about 37~86%, it was increased with increase of operation temperature in pyrolysis. And the yield of pyrolytic oil was increased with increase of heating rate. The maximum oil yields of IR, NR, BR, SBR, and tire were 80, 73, 83, 86 and 55% each at $700^{\circ}C$ with a heating rate of $20^{\circ}C$/min, respectively. The pyrolytic oil components were consisted of about 50 aromatic compounds. The calorific value of purolytic oil of commercial rubber, SBR, and tire was measured by calorimeter, it was 39~40 kJ/g. The BET surface area of pyroblack was $47~63m^2/g$. The optimum condition of pyrolysis was operating temperature of $700^{\circ}C$ with heating rate of $20^{\circ}C$. Therefore, the pyrolytic oil and pyroblack are possible to alternative fuel and carbon black.

• Korean Chemical Engineering Research
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• 제47권3호
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• pp.303-309
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• 2009

폐 농업용 비닐을 이용한 연료유 생산 공정을 위한 저밀도폴리에틸렌(LDPE)과 에틸렌비닐아세테이트(EVA) 수지에 대한 열분해 반응 실험을 하였다. 질소 분위기에서 상온에서 $650^{\circ}C$까지의 비등온 조건에서의 열분석기(열중량분석기, 시차주사열량계)와 $420^{\circ}C$의 배치형 반응기에서 무촉매 반응과 천연제올라이트, FCC 촉매, 폐 FCC 촉매, 중국 촉매(촉매 A) 등의 제올라이트계 촉매를 사용한 열분해가 행하여졌다. TGA 실험에서 무적제가 첨가된 EVA 수지는 열분해 개시 온도가 $250^{\circ}C$ 근처로 매우 낮아졌으나, 황토와 장수제 첨가는 열분해를 다소 지연시켰다. LDPE에서 제올라이트 계열 촉매는 촉매 A>폐 FCC 촉매>천연제올라이트>LDPE의 순으로 열분해 반응속도를 높이는데 유효하였다. EVA에서 제올라이트 계열 촉매 첨가 시는 폐 FCC 촉매>천연제올라이트>촉매 A>EVA 수지의 순으로 열분해 반응을 촉진시켰다. DSC 실험에서 제올라이트 계열 촉매 첨가 시 촉매 A>폐 FCC 촉매>천연제올라이트>LDPE의 순으로 융해개시 온도와 열분해열이 낮아졌다. 회분식 실험에서 천연제올라이트 첨가 시 시료 중 가장 높은 액상의 연료유 생성수율을 얻었다.

• 한국응용과학기술학회지
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• 제33권4호
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• pp.676-685
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• 2016

본 연구는 폴리스타렌(PS) 수지의 유화공정 효율성 향상을 위해 저온열분해 회분식 반응기를 이용하여, 단일 PS 수지와 Co 및 Mo 촉매를 각각 첨가한 PS 수지를 반응온도(425, 450, $475^{\circ}C$), 반응시간(20~80분, 15분 간격), 촉매 농도변화에 따른 PS수지의 액화생성물 전환율을 측정하였다. 최적의 열분해 조건은 반응온도 $450^{\circ}C$, 반응시간 35분으로 판단되며, 전환된 액화생성물의 주요 성분은 GC/MS 분석결과 스타이렌 및 벤젠유도체가 대부분으로 나타났다. 생성물은 산업통상자원부에서 고시한 증류성상 온도에 따라 가스, 가솔린, 등유, 경유, 중유로 분류하여 그 수율을 측정하였다. 그리고 $450^{\circ}C$ 반응온도에서 촉매 사용에 따른 전환율은 Co 촉매 > Mo 촉매 > 무촉매 순이었으며, 생성물 중 가스, 등유, 경유수율은 Mo 촉매, 가솔린은 무촉매, 중유는 Co 촉매에서 우수한 것으로 나타났다. Co 및 Mo 촉매 혼합 농도별 전환율 및 열분해 생성물 수율은 Co 촉매 100% 사용 시 가장 우수한 것으로 판단된다.