$\alpha$-Fe$_2$O$_3$의 가스감지특성에 미치는 황산이온의 영향

양천희 한국안전학회 1989 한국안전학회지 Vol.4 No.1

The $\alpha$-Fe$_2$O$_3$ gas sensor, prepared by the precipitation of Fe(OH)$_3$ from a solution of iron(III) sulfate and tin (IV) chloride, was composed of fine particles and was superior in sensitivity to other $\alpha$-Fe$_2$O$_3$. The gas sensitivity was found to depend on the amounts of remaining sulfate ion the microstructure and a small amount of iron(II) species generated through the reduction of $\alpha$-Fe$_2$O$_3$. The sensing mechanism of $\alpha$-Fe$_2$O$_3$gas sensor was confirmed to be due to the reduction of $\alpha$-Fe$_2$O$_3$ to the low resistive Fe$_3$-xO$_4$ by combustible gas and to depend on the crystral structure.

원자가 조절에 의한 Cr_2O_3센서의 Trimethylamine 감지특성

양천희 한밭대학교 산업과학기술연구소 1993 논문집 Vol.1 No.-

To develop a new type of semiconductor gas sensors capable of testing freshness of fish, attempts were made enhance the sensitivity to trimethylamine(TMA) by modifying the carrier concentration of metal oxides by means of the valency control method. The TMA sensitivity of Cr_2O_3 was markedly improved by partial substitution with 5mol% Ti^4+ ions for the Cr^3+ sites. These facts suggest that the sensitivity can be enhanced by reducing the carrier concentration of the oxides.

공정변수를 조절한 폴리에틸렌 산화왁스 합성에 관한 연구

양천희 ( Chun Hoe Yang ) 한국유화학회 2003 한국응용과학기술학회지 Vol.20 No.2

N/A Oxidised polyethylene wax is obtained by oxidation of polyethylene wax and it is composed of various chemicals, e,g., fatty acid, alcohol, ketone and ester. The application of oxidized polyethylene wax is determined by the composition of these chemical substances. In this basic study we observed the basic reaction parameters of time, temperature, oxugen concentration and catalysts on the oxidation reaction of low molecular weight polyethlene(PE wax) by analyzing the acid value, physical and hemical properties of oxidized PE wax to develop a new oxidation process. Acid values are increased with temperature increase in the rage of 150℃~180℃, but decreased beyond 190℃ Acid values are also increased with oxygen concentration As the oxidation reaction proceeds the molecular weight and softening points of oxidation products are decreased by cracking reaction, but the viscosities are increased To observe the crystallinity of oxidation products SEM experiment was performed. To obtan a high acid-value product in a mild condition, we adopted free radical catalysts and the acid value of the product using catalyst was higher than the product obtained without catalyst in the same reaction condition. The effective initiators were dicumyl peroxide(DCPO), t-butylperoxy-2-ethyl hexanoate(HOPO) and benzoyl peroxide(BPO) having long half-life.

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.

2001 춘계 학술발표회 논문집 : 졸 - 겔법으로 제조된 TiO2 촉매에 의한 합성세제의 광분해 효과

최윤석,양천희 한국안전학회(구-한국산업안전학회) 2001 2001년 춘계 학술발표회 논문집 Vol.- No.-

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.

석탄회를 이용한 제올라이트의 합성과 중금속 흡착 특성

류완호,이원묵,홍필선,양천희,안재영,백일현,이병노 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.5

석탄회를 이용, 중금속 제거용 흡착제 제조를 목적으로 NaOH를 반응물로 한 수열합성 반응으로 제올라이트를 합성하였으며, 이에 대한 성능특성 및 중금속 흡착실험을 수행하였다. SiO₂와 Al₂O₃를 주성분으로 한 석탄회를 NaOH에 의한 수열합성 반응으로 폐수 중에 포함되어 있는 중금속에 대한 제거능력이 높은 제올라이트를 합성하고자 하였다. 따라서 NaOH 농도, 시간을 변화시키면서 제올라이트를 합성하여 실험한 결과 4 M-NaOH, 4시간에서 최적의 조업조건을 얻을 수 있었다. 산에 의한 전처리 과정을 거친 합성 제올라이트는 pH 7-9.5로 중성을 나타내었다. 또한 산처리 합성 제올라이트를 이용하여 중금속인 P, Pb, Cd, Cr, Mn등의 흡착능을 비교한 결과 P, Pb, Cd 등은 비교적 흡착능이 우수하게 나타났지만 Cr과 Mn 등은 pH가 너무 높기 때문에 거의 흡착이 이루어지지 않았다. Zeolite was synthesized from coal fly ash produced by a domestic power plant and has applications in the removal of heavy metal from waste water. Zeolite was synthesized using a hydrothermal method involving an alkaline reaction with NaOH. The NaOH concentration and reaction times were varied in order to synthesize zeolite showing the maximum removal efficiency of heavy metal from waste water. The synthesis conditions were optimized at the concentration of 4M-NaOH and the reaction time of 4hn. The synthesized zeolite needed washing with HCI solution to improve the removal efficiency of P, Pb. Cd. Cr. Mn and it was maximized at pH 7-9.5 in leaching solution of synthesized zeolite.

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.

재생 염화 철 에칭액에 잔류하고 있는 유기첨가물 모니터링방법

심환보,조영근,김인홍,박광호,박종무,양천희 한국공업화학회 2005 응용화학 Vol.9 No.1

In this study, the method analyzing and monitoring organic additives within the recycled ferric chloride etching solution was proposed. Generally, Gas Chromatography, Raman and Infra--Red spectroscopy have been used as the quantitative analysis method of organic compounds. Of them, InfraRed spectroscopy was respected as the most competitive tool in the reason of easy-maintenance, lower installation cost , lower analytical error and so on. And it can be used as the monitoring tool in process lines for production. So, we investigated the basic points of extract(pre-treating agent), sample container and conditions considering IR spectroscopy.

졸-겔법에 의한 TiO2 분체 합성 및 주방용 합성세제의 광분해 효과

정용준(Chung YoungJoon),류완호(Roo WanHo),양천희(Yang ChunHoe) 한국유화학회 2004 한국응용과학기술학회지 Vol.21 No.2

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^{circ}C. 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 TiO2 catalysts. 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 initial value.