In polymer precursor based activated carbon, the structure of starting material is likely to have profound effect on the surface properties of end product. To investigate this aspect phenolic resins of different types were prepared using phenol, mcresol and formaldehyde as reactants and Et3N and NH4OH as catalyst. Out of these resins two resol resins PFR1 and CFR1 (prepared in excess of formaldehyde using Et3N as catalyst in the basic pH range) were used as raw materials for the preparation of activated carbons by both chemical and physical activation methods. In chemical activation process both the resins gave activated carbons with high surface areas i.e. 2384 and 2895 m2/g, but pore size distribution in PFR1 resin calculated from Horvath-Kawazoe method, contributes mainly in micropore range i.e. 84.1~88.7 volume percent of pores was covered by micropores. Whereas CFR1 resin when activated with KOH for 2h time, a considerable amount (32.8%) of mesopores was introduced in activated carbon prepared. Physical activation with CO2 leads to the formation of activated carbon with a wide range of surface area (503~1119 m2/g) with both of these resins. The maximum pore volume percentage was obtained in 3-20 a region by physical activation method.

Pyrolysis of polypropylene(PP) Was performed to find the effects of the pyrolysis temperature(425, 450, 475 and 500℃) and the pyrolysis time(35, 50 and 65minutes), respectively. Conversion and liquid yield obtained during PP pyrolysis continuously increased with the pyrolysis temperature( up to 500℃) and the pyrolysis time(up to 65minutes), especially these were more sensitive to the pyrolysis time at 425℃ than other pyrolysis temperatures. Each liquid product formed during the pyrolysis was classified into gasoline, kerosene, light oil and wax according to the distillation temperature based on the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. The liquid products of PP pyrolysis up to 450℃ were almost same fractions(26±3wt.% gasoline, 20±2wt.% kerosene and 23±2wt.% light oil) except wax(3~13wt.%). On the other hand, the pyrolysis of PP from 475℃ to 500℃ produced 26±3wt.% wax, 24±1wt.% gasoline, 18±1wt.% kerosene and 16±1wt.% light oil. After all, the main liquid product changed from gasoline to wax with increasing pyrolysis temperature.

Isothermal pyrolysis of high density polyethylene(HDPE), polypropylene(PP) and polystyrene(PS) was performed at 450℃, respectively. The effect of pyrolysis time on yield and product composition was investigated. Conversion and liquid yield obtained during HDPE pyrolysis continuously increased with time up to 80minutes, but those of PP and PS did not largely change after 35minutes. Each liquid product formed during the pyrolysis was classified into gasoline, kerosene, light oil and wax according to the distillation temperature based on the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. The major liquid product of HDPE pyrolysis was light oiH34 wt.% based on the amount of HDPE treated) and the amounts of the other liquid ingredients(gasoline, kerosene and wax) were almost the same. On the other hand, the pyrolysis of PP produced 27 wt.% gasoline, 22 wt.% kerosene, 24 wt.% light oil and 13wt.% wax, and the pyrolysis of PS produced 56 wt.% gasoline, 12 wt.% kerosene, 9 wt.% light oil and 13 wt.% wax.

The polycrystalline CdS of large scale were grown by chemical pyrolysis deposition for Cu2S/CdS heterojunction solar cells. For high quality CdS polycrystalline thin films, the chemical solution was deposited on indium tin oxide(ITO) glasses at the temperature of 500℃ for 15 second and annealed at 350℃ for 20 minute or 500℃ for 30 second. To fabricate high efficiency solar cells, optical and electrical properties, morphology by SEM and x-ray diffraction on polycrystalline CdS thin films were investigated. From the I-V characteristics of Cu2S/CdS heterojunction, the open circuit voltage, Voc was 0.7 V and the short circuit current, Isc was 4.2 mA. We found that the fill factor(FF) was 0.5 and the efficiency was 2.5%.

MgO based nanocomposite powder including ferromagnetic iron particle dispersions, which can be available for the magnetic and catalytic applications, was fabricated by the spray pyrolysis process using ultra-sonic atomizer and reduction processes. Liquid source was prepared from iron (Fe)-nitrate, as a source of Fe nano-dispersion, and magnesium (Mg)-nitrate, as a source of MgO materials, with pure water solvent. After the chamber were heated to given temperatures (500~), the mist of liquid droplets generated by ultrasonic atomizer carried into the chamber by a carrier gas of air, and the ist was decomposed into Fe-oxide and MgO nano-powder. The obtained powders were reduced by hydrogen atmosphere at 600~. The reduction behavior was investigated by thermal gravity and hygrometry. After reduction, the aggregated sub-micron Fe/MgO powders were obtained, and each aggregated powder composed of nano-sized Fe/MgO materials. By the difference of the chamber temperature, the particle size of Fe and MgO was changed in a few 10 nm levels. Also, the nano-porous Fe-MgO sub-micron powders were obtained. Through this preparation process and the evaluation of phase and microstructure, it was concluded that the Fe/MgO nanocomposite powders with high surface area and the higher coercive force were successfully fabricated.

Porous carbons have been prepared from different parts of banana stems using two different routes, viz., by pyrolysing the mass at different temperatures as well as by treating the dried mass with chemicals followed by pyrolysis. The pyrolysis behaviour of all these materials has been studied up to 1000℃. Samples treated with acids exhibit more increase in surface area as compared to those treated with alkalies or salts. Analysis of BET surface area shows that the carbon prepared at low temperature shows mixed porosity, i.e., micro and mesopores. Samples heated to high temperature above 700℃ show decrease in macroporosity and increase in microporosity. Liquid adsorption studies have been made using methylene blue and heavy oil. The activated carbons so prepared exhibit higher oil adsorption mainly in the macro and mesopores.

The formation, microstructure and properties of novel ceramic composite materials manufactured by active-filler-controlled polymer pyrolysis were investigated. In the presence of active filler particles such as transition metals, bulk components of various geometry could be fabricated from siliconorganic polymer. Molybdenum- and tungsten-filled polymer suspensions were prepared and their conversion to ceramic composites by annealing in atmosphere were studied. Dimensional change. porosity and phase distribution (filler network) were analyzed and correlated to the resulting hardness values. Molybdenum and tungsten as active filler were carburized completely to , and WC in atmosphere. Consequently, microcrystalline composites with the filler reaction products embedded in a silicon oxycarbide glass matrix were formed. Hardness was increased with increasing carburization and reached 8.6-9.5 GPa in the specimen pyrolyzed in atmosphere.

태양전지의 앞면전극으로 사용될 SnO2박막을 spray pyrolysis 방법으로 증착하여 증착조건에 따른 박막 특성을 연구하였다. 증착온도가 증가함에 따라 SnO2박막의 우선방위가 (200)면에서 면밀도가 더 높은 (211), (110)면으로 바뀌었고 막의 미세구조도 거칠고 각진 구조에서 평탄한 구조로 변하였다. 또한 더 안정된 결정면 성장과 온도 증가에 의해 CI, F 등의 불순물 흡착이 어려워져 전자 전하농도가 감소하고 비저항 값이 증가하였다. 특히 500˚C 이상에서는 전하농도가 크게 감소하여 비저항이 크게 증가하였다. NH4F/Sn=2.3인 용액으로 400˚C에서 증착된 SnO2박막은 약 90%이상의 광투과도를 갖고 균일한 도핑으로 인해 약 4×10-4Ω .cm의 낮은 비저항 값을 나타내었다. 두께에 따른 판저항과 광투과도의 상반된 효과를 고려한 figure of merit으로부터 투명전극으로써 가장 적절한 두께는 약 500nm이었다.