금속염을 함침한 TiO₂ 소결체의 전기 비저항 - 온도 특성

홍필선(Hong Phil Sun),양천희(Cheon Hoi Yang) 대한공업교육학회 1985 대한공업교육학회지 Vol.10 No.1

Titanium oxide sintered in air at 1000℃ for 2 hours was impregnated with several kinds of metallic salts in aqueous solution. The electrical resistivity of sintered bodies was measured as a function of the temperature by electrical multimeter. When the resistivity of specimen doped antimony was measured in air during the heating, two step extrema was observed. The first extrema in the low temperature was explained in terms of the desorption of the chemisorbed oxygen and oxidation, and the second extrema in the high temperature was by the precipitation of Sb₂O₃. In case of specimen doped Aluminum, the extrema was not appeared but the thermal hysteresis was done. These phenomena were explained in terms of the principle of controlled valency.

스피넬상 마그네타이트를 이용한 $CO_2$ 분해의 최적조건

류대선,홍필선,이풍헌,김순태,Ryu, Dae-Sun,Hong, Phil-Sun,Lee, Poong-Hun,Kim, Soon-Tae 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.10

이산화탄소($CO_2$)분해를 위해 $0.2M-FeSO_4{\cdot}7H_{2}O$와 0.5 M-NaOH를 사용하여 공기산화법으로 magnetite를 합성하였다. 합성한 magnetite를 2시간 동안 수소($H_2$)로 환원하여 325, 350, 375, 400, $425^{\circ}C$에서 이산화탄소의 분해반응을 실시하였다. 실험결과 $350^{\circ}C$에서 이산화탄소의 분해율이 88%로 가장 우수한 것으로 나타났으며, magnetite를 이용한 이산화탄소의 분해에 대한 활성화에너지는 30.96 kJ/mol이였다. 이산화탄소의 분해 후 촉매 표면의 탄소와 수소가 반응하여 메탄을 생성하였다. Magnetite was synthesized using $0.2M-FeSO_4{\cdot}7H_{2}O$ and 0.5 M-NaOH by air oxidation method for carbon dioxide decomposition to carbon. The carbon dioxide decomposition was successfully carried out after reduction of ${Fe_3}{O_4}$ for 2 hrs using hydrogen gas. The carbon dioxide decomposition at 325, 350, 375, 400, $425^{\circ}C$, 88% was the highest at $350^{\circ}C$ and the activation energy of ${Fe_3}{O_4}$ in carbon dioxide decomposition was 30.96 kJ/mol. After $CO_2$ decomposition, the carbon of surface of catalyst reacted with hydrogen produced methane.

석탄회를 충전한 불포화폴리에스테르 수지에 관한 연구

이학용(Hak Yong Lee),홍필선(Phil Sun Hong),이성구(Sung Goo Lee) 대한환경공학회 1997 대한환경공학회 학술발표논문집 Vol.1997 No.12

xTiO2 - y SiO2 광촉매에 의한 유기물의 광분해

양천희(Chun Hoi Yang),이철우(Chul Woo Lee),홍필선(Phil Sun Hong),이원묵(Won Mook Lee) 한국물환경학회 2000 한국물환경학회지 Vol.16 No.1

TiO₂ and x TiO₂- y SiO₂ system photocatalysts were developed by sol-gel method based on the change of production parameters, and their structure of crystallization and the specific surface area were measured. Considering the efficiency of the ethanol and phenol degradation using the catalyst, the conclusions were obtained as follows: ①. By means of X-ray analysis of TiO₂ powder that is obtained from water and Titanium alkoxide with various molar ratios, it is shown that crystal structure of anatase type is a dominating structure and, on the other hand, the structure of rutile also partly exists. The specific surface area is at its maximum value at R=6, which is the molar ratio of water vs. alkoxide, whereas its value goes down as the molar ratio increases. ②. xTiO₂- y SiO₂ system photocatalysts were developed from Titanium and Silicon alkoxide by a hetero-condensation process. The increase of SiO₂ contents causes the decrease of the degree of crystallization of the gel, whereas the specific surface area preferentially increases. It is shown that more than 90% of ethanol and phenol are degraded when reaction time is about three and an hours, and the maximum degradation rate of ethanol and phenol is shown in 60TiO₂-40SiO₂ catalyst.

Sensor 素材로서 질화 알루미늄에 대한 로듐의 첨가효과

洪弼善 大田開放大學 1986 論文集 Vol.5 No.-

A gas sensor was prepared by calcining rhodium nitrate supported on aluminium nitride at various temperatures in a N_2 stream. The sensitivity of the gas sensor increased linearly with CO gas concentration below 3000 ppm at 180℃ and 220℃, while addition of rhodium nitrate over 3 wt%, was not effective. The sensor calcined at 1000℃ was twice as sensitive as that calcined at 600℃. Rhodium nitrate decomposed to Rh_2O_3 at high temperature. The apparent porosity of the gas sensor was about 50% and this value was kept constant after annealing. It is considered that aluminium nitride is a good material as a support.

상수처리에 있어 이산화염소의 효과에 관한 연구

홍필선,박영구 大田産業大學校 1993 한밭대학교 논문집 Vol.10 No.1

ABSTRACTThe chlorine has been used as one of the drinking water supply system, it be used universally the most economic chemical treatment and effect chemical threatment.But, in chlorine treatment, the residual chlorine in drinking water reacts with organic materials (humic substances), and to produce THMs(trihalomethanes) which is known as carcinogenic substance.In the experiment, sample of drinking water was mixed that chlorine used in the original disinfectants were summaried as be more effect then the above single treatment (chlorine) dissolved oxygen, KMnO4 consume degree, and ferric, phenol, general bacteria, trihalomethanes. The chlorine has been used as one of the drinking water supply system, it be used universally the most economic chemical treatment and effect chemical threatment. But, in chlorine treatment, the residual chlorine in drinking water reacts with organic materials (humic substances), and to produce THMs(trihalomethanes) which is known as carcinogenic substance. In the experiment, sample of drinking water was mixed that chlorine used in the original disinfectants were summaried as be more effect then the above single treatment(chlorine) dissolved oxygen, KMnO_4 consume degree, and ferric, phenol, general bacteria, trihalomethanes.

Perovskite형 La₁-xSrxMnO₃의 합성에 미치는 SrO의 영향

홍필선 大田産業大學校 1995 한밭대학교 논문집 Vol.12 No.1

The La_(1-x)Sr_xMnO_3 was synthesized LaMnO_3 compound by the partial replacement of lantanium with strontium. The analysis of the synthetic compound showed that it was perovskite type to x=0.8. And it also showed that as the amount of strontium increased, the lattice parameter decreased though it was expected to increase. I think that the result was because Mn^3+ was changed Mn^4+ which had smaller ionic radius.

LaMnO₃의 CO가스 감지 특성에 미치는 SrO의 영향

홍필선 大田産業大學校 1995 한밭대학교 논문집 Vol.12 No.1

The La_(1-x)Sr_xMnO_3 compounds wers synthesized from the perovskite-type perovskite-type LaMnO_3 compound by the partial replacement of lantanium with strontium. The sensitivities on carbon monoxide were measured at various temperatures, respecticely. The electrical resistivities and catalytic activties were examined about there having an effect on the gas- sensing in company with the effect of addition of strontium.

졸 - 겔법으로 제조된 TiO2 촉매에 의한 합성세제의 광분해

홍필선,양천희 한국산업안전학회 2000 한국안전학회지 Vol.16 No.3

An aqueous solution of a commercial liquid synthetic detergent for kitchen use was photodecomposed in the presence of titanium dioxides powder under an atmosphere of air at room temperature. Titanium dioxides were prepared by sol-gel method from titanium iso-propoxide at different R ratio(H₂O/titanium iso-propoxide) and calcined at 500℃. All titanium dioxides were characterized by XRD, BET surface area analyzer and UV-VIS spectrometer. The surface area of titanium dioxides prepared at R ratio=6 appeared higher volume about 20% than commercial TiO₂catalysts. XRD patterns of titania particles were observed mixing phase together with rutile and anatase type. Titanium dioxides prepared by sol-gel method show higher activity about 6% than commercial TiO₂ catalysts on the photocatalytic degradation of a commercial liquid synthetic detergent for kitchen. The concentration of the detergent decreased to about 90% of its initial value at illumination times of 2 hour. Illumination for 30 minutes decreased the concentration of oxygen to about one-fifth of the inital value.

K?CO?를 가압수열 반응시킨 ?-Fe?O?의 합성

박영구,홍필선 大田工業大學 1990 한밭대학교 논문집 Vol.7 No.1