• 한국세라믹학회지
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• 제42권1호
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• pp.7-10
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• 2005

[ $TiO_{2}-ZrO_{2}$ ] powders were successfully synthesized by the sol-gel process using titanium iso-propoxide as a precursor. The amorphous $TiO_{2}$ particles, 70 nm in size, homogenously adhered to the surface of $ZrO_{2}$ the powders. After calcination at $450^{circ}C$, most of the $TiO_{2}$ powders appeared as an anatase type, whereas they changed to a rutile phase at $750^{circ}C$. For comparison of photocata­lytic activity, $TiO_{2}-ZrO_{2}$ nano-sized powders calcined at $450^{circ}C,\;600^{circ}C,\;and\;750^{circ}C$ were used. In the $TiO_{2}-20wt\%$ $ZrO_{2}$ powders cal­cined at $450^{circ}C$, there was excellent removal efficiency of Methyl Orange (MO). For the calcination temperature increased, $TiO_{2}­ZrO_{2}$ nano-sized powders increased $ZrO_{2}$ contents showed the good photoactivity for the photooxidation of MO.

• Journal of Ginseng Research
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• 제11권2호
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• pp.91-100
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• 1987

인삼(Panax ginseng C.A. Meyer) 엽소병에 대한 고사원인을 현상학적 측면에서 관찰, 분석한 결과 chlorohphyll의 bleaching현상은 적색광(660~700nm)에서 일어났으며, 청색광(400~500nm)에서는 광산화에 의한 bleaching현상이 일어나지 않았다. 엽소병에 의한 고사원인으로 대두되었던 환경요인 "온도"는 chlorohphyll의 bleaching현상에 전혀 영향을 미치지 않았다. 따라서 단순연소(simple burning)설은 본 실험을 통해 배재되었으며, 낮은 pH는 chlorohphyll의 bleaching속도를 가속화시켜 주었다. 엽소병에서 chlorohphyll의 bleaching현상을 유발시키는 1차적요인은 인삼잎의 독특한 구조적 차이에 의한 것이었다.

• Journal of Photoscience
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• 제9권3호
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• pp.65-70
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• 2002

In the rice leaves treated with methyl viologen (MV), the photochemical efficiency of PSII (or $F_{v/}$F $m_{m}$) was significantly decreased, and significant portion of the photoinactivation process was reversible during the dark-recovery. The dark-reactivation process was relatively slow, reaching its plateau after 2-2.5 h of dark incubation. The damaged portion of functional PSII was 13％, based on the value of I/ $F_{o}$- I/ $F_{m}$ after this dark-recovery period. The reversible photoinactivation process of PSII function in the MV-treated leaves consisted of a xanthophyll cycle-dependent development of NPQ and a xanthophyll cycle-independent process. The latter process was reversible in the presence of nigericin. As well as the increase in the values of Chl fluorescence parameters, the epoxidation process during the dark-recovery after the MV-induced photooxidation was very slow. These results suggest that the photooxidative effect of MV is partly protected by the down-regulation of PSII before inducing physical damages in core proteins of PSII.I.I.I.I.

• 한국환경과학회지
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• 제15권6호
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• pp.533-538
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• 2006

Removal of $NO_x$ on $CaO/TiO_2$ photocatalyst manufactured by the addition of $Ca(OH)_2$ was measured in relation with the amount of $Ca(OH)_2$ and calcination temperature. In case of pure $TiO_2$, the $NO_x$ removal decreased greatly with the increase of calcination temperature from $500^{\circ}C\;to\;700^{\circ}C$, whereas in the photocatalyst added with $Ca(OH)_2$, the removed amount of $NO_x$ was high and constant regardless of calcination temperature. Considering $NO_x$ removal patterns depending on the amount of $Ca(OH)_2$ added(50, 30, 10wt%), high removal rate showed at the photocatalysts containing less than 30wt% of $Ca(OH)_2$, and it was about 30% higher than that of pure $TiO_2$. From the XRD patterns, it is seen that the addition of $Ca(OH)_2$ contributes to maintaining the anatase structure that is favourable to photocatalysis. It also indicates that the possibility of the formation of calcium titanate($CaTiO_3$) by reacting with $TiO_2$ above $700^{\circ}C$. Apart from the favourable crystalline structure, the addition of $Ca(OH)_2$ helped increase the alkalinity of photocatalyst surface, thus promoting the photooxidation reaction of $NO_x$.

• Rapid Communication in Photoscience
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• 제3권4호
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• pp.70-72
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• 2014

Visible-light irradiation of MeCN solution containing di(hydroxo)metallo(tetraphenyl)porphyrin complex $(tppM(OH)_2$: 1a; $M=Sb(V)^+Br^-$, 1b; $M=P(V)^+Cl^-$, 1c; M=Ge(IV)) and 2-mercaptoethanol (2-ME) as a substrate under aerated condition gave bis(2-hydroxyethyl)disulfide (2-HEDS) as an oxidative product of 2-ME. It is indicated that the oxidation of 2-ME should proceed with a photocatalytic process by 1, because the turn over number (TON) for the formation of 2-HEDS was over unit. The TON was determined to be 642 as a maximum value when 1a was used as a sensitizer. The formation of 2-HDES was extremely slow under argon atmosphere. The fluorescence of 1 was not quenched by 2-ME at all, and the free energy change (${\Delta}G$) with electron transfer (ET) from 2-ME to excited triplet state of $1(^31^*)$ was estimated as a negative value. The quenching rate constant ($k_r$) of $^31^*$ by 2-ME, obtained by the kinetics for the formation of 2-HEDS, strongly depends on ${\Delta}G$. These findings indicate that 1-sensitized oxidation was initiated by photoinduced ET from 2-ME to $^31^*$ to generate both radical cation of 2-ME ($2-ME^{+\bulle}$) and porphyrin radical anion ($1^{-\bulle}$), resulting that the formation of 2-HEDS can be proceeded by the dimerization of $2-ME^{+\bulle}$, and through a catalytic cycle due to returning to 1 by the ET from $1^{-\bulle}$ to molecular oxygen.

• 상하수도학회지
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• 제18권3호
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• pp.377-384
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• 2004

In the present study, a feasibility of an advanced oxidation process using UV/Hydrogen peroxide($H_2O_2$) system equipped with a medium pressure lamp for secondary effluent reclamation was investigated. Initial concentration of $H_2O_2$ and pH were changed to determine the optimum operation condition for the system. The removal efficiency of color was than 80% with 14.3mg/L of initial $H_2O_2$ and 5 minute of contact time in the UV/$H_2O_2$ system. The color removal was analyzed using first-order reaction equation. The dependence of rate constant (k) on initial $H_2O_2$ represented the rational relationship with maximum value. Residual $H_2O_2$ caused increase of effluent COD, since analyzing agent, dichromate, reacted with $H_2O_2$ in the sample. Therefore, excess initial concentration of $H_2O_2$ would significantly affect effluent COD measurement. At pH variation experiment, both residual $H_2O_2$ and color showed peak in the neutral pH range with the same pattern. Effect of $H_2O_2$ dose also enhanced color removal but raised residual $H_2O_2$ problem in the continuous operation UV system. In conclusion, these results indicated that medium pressure UV/$H_2O_2$ system could be used to control color in the secondary effluent for reclamation and reuse.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3351-3355
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• 2013

Photodynamic therapy (PDT) is a promising cancer treatment modality that uses dye-sensitized photooxidation of biologic matter in target tissue. This study explored effects of the photosensitizer BCPD-17 during PDT for osteosarcoma. LM-8 osteosarcoma cells were treated with BCPD-17 and cell viability after laser irradiation was assessed in vitro with the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The effects of BCPD-17 during PDT recurrence were then examined on tumor-bearing mice in vivo. BCPD-17 had dosedependent cytotoxic effects on LM-8 osteosarcoma cells after laser irradiation which also had energy-dependent effects on the cells. The rate of local recurrence was reduced when marginal resection of mice tumors was followed by BCPD-17-mediated PDT. Our results indicated BCPD-17-mediated PDT in combination with marginal resection of tumors is a potentially new effective treatment for osteosarcoma.

• 한국식품과학회지
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• 제43권3호
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• pp.255-262
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• 2011

본 연구에서는 비발아들깨와 12, 36, 48시간 발아시킨 들깨로 부터 유지를 추출한 후 $60^{\circ}C$의 빛이 차단된 상태 또는 빛의 존재 하에 4일 동안 저장하면서 가속조건에서의 유지 산화 및 토코페롤 안정성을 평가하였다. 들깨유의 과산화물값과 공액이중산 값은 저장기간이 증가함에 따라 유의하게 증가하였으며, 비발아 들깨유에 비해 발아들깨유에서 낮은 경향을 보였다. 또한 빛이 차단된 조건에 비해 빛 존재 하에서 들깨유의 산화와 토코페롤 분해가 더 많이, 더 빨리 진행되었다. 들깨유 중 12시간 발아시킨 들깨로부터 추출한 들깨유는 유의하게 낮은 공액이중산값과 토코페롤의 낮은 분해속도 등에 기인하여 가장 높은 자동산화, 광산화 안정성을 보여주었다.

• 상하수도학회지
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• 제17권4호
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• pp.542-549
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• 2003

In the present study, the feasibility of $UV/H_2O_2$ systems was investigated using low and medium-pressure lamps on biologically treated wastewater effluents for secondary effluent reclamation. Two types of UV lamps were used as the light sources (a 39-W low-pressure mercury lamp and a 350-W medium-pressure mercury lamp). The results from these UV systems showed that the removal of organic compounds could be achieved in the contact time of longer than 30min (i.e., low UV doses). Efficiencies of color removal and disinfection were far better than those of organic matters measured as TOC, DOC and $TCOD_{cr}$. In the low-pressure lamp UV system, it has been found that DOC and color removals were 60.9 and 86.2% with 50mg/L of $H_2O_2$ and contact times of 30 minute, respectively. Whereas, with the medium-pressure lamp UV system, TOC, DOC and color removal were 27.1, 5.6 and 95% with 14.3mg/L of $H_2O_2$ and 14 minute of contact times, respectively. Both systems could be applied for the reclamation of secondary effluent treated with biological treatment processes.

• Applied Biological Chemistry
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• 제38권3호
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• pp.259-262
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• 1995

DHA(cis-4,7,10,13,16,19-docosahexaenoic acid)가 첨가된 분유와 보통분유의 저장중 지방의 산화안정성을 thiobarbituric acid법에 의해 살펴보았다. 두 종류의 분유는 지역의 슈퍼마켓에서 구입하여 시료병에 $2{\pm}0.05\;g$씩 넣어 암소와 빛의 존재하에서 저장하였다. DHA가 첨가된 분유 지방 산화는 보통 분유보다 증가되었고 특히 빛의 존재하에서 산화는 더욱 촉진되었다. 빛과 DHA를 포함한 불포화지방산은 분유지방을 산화시킴에 있어 상호 역할을 강화시키고 있었다. DABCO (diazabicyclooctane)를 분유에 첨가하면 빛에 노출된 분유의 지방 산화를 줄였는데 이는 분유에서도 일중항산소에 의한 광산화가 발생함을 암시한다. DABCO에 의한 유지방의 산화 억제 정도는 DHA가 첨가된 분유에서 높게 나타났다.