Development of a Method for Measuring the Ozone Concentration in the Atmosphere Using Passive Method
1. Introduction Passive method is widely used for measuring air pollutant for one day to several weeks. This method can be used easily and doesn’t need electricity, but expensive devices are needed for measuring substances, so this is not suitable for high school students for measuring or investigating. Then, we focused on the reaction, in which Indigo, the blue pigment, is discolored by ozone, and we built up a hypothesis, that indigo is suitable for measuring ozone concentration. 2. Experimental Section We soaked a 10 mm×20 mm filter paper in an indigo solution, including hosphoric acid. Then, they were dried in an automatic oven. 5.5 cm×10 cm PTFE sheet was fold in two and five sheets of indigo filters were fixed inside (passive sampler). The passive samplers were fixed on a stand and exposed to ozone in the atmosphere. After a few days, we collected the samplers and put each indigo filter and 4.0 mL of ion-exchange water into sample tubes. Then we shook this and extracted the color pigment. We had the average value of 600 nm from the five sheets as a measure value. 3. Results and Discussion The total amount of ozone for one to seven days measured in the experiment was directly proportional to the amount of ozone measured by Osaka Prefecture. We found that we can measure ozone in atmosphere using our method. Passive method has an advantage: it can be carried out easily. We employed this trait and measured ozone concentration at 23 points simultaneously in the north of Osaka for 48 hours. We made the map of ozone concentration by marking on a blank map. The map we made was just like the map published by Osaka Prefecture. We expect that this method will be useful in measuring ozone, where measuring devices are not available. 4. Conclusion We succeeded developing new method for measuring ozone in the atmosphere by passive method using indigo, the blue pigment.
Artificial Photosynthesis -Formic Acid Generated from Carbon Dioxide by Using Photocatalyst-
Reduction of carbon dioxide is desired as an environmental problem of global warming. The study of generation of formic acid from carbon dioxide was performed under irradiation of ultra violet to photocatalyst. Ta2O5 could reduce carbon dioxide, but the band gap of Ta2O5 was 4.0 voltage. In this research, it was found that tantalum oxide / tantalum plate responds to visible radiation. Therefore, the reason of visible light response was examined. It was studied to make efficient tantalum oxide / tantalum plate.
在Sapphire 基材上以電化學沉積YAG 螢光薄膜
A novel method of electrolytic Y3Al5O12 (YAG:X, X=Ce, Eu, Tb) phosphor thin-film coating on sapphire was investigated in yttrium, aluminum, cerium, europium and terbium nitrate solution. By means of X-ray diffraction (XRD), scanning electronic microscopy (SEM) observation, and cathodic polarization tests, the most efficient potential of deposition was found in the region between -1.2 V~-1.5 V. The YAG phosphor thin-film was successfully synthesized by the cathodic deposits were heat-treated at 1200 ℃ for 4 hours. The excitation photoluminescence (PL) spectra of Ce3+ in YAG consists of a strong maximum at about λ＝520~530 nm that show yellow emission peak, and a red emission was observed at about λ＝595~700 nm by additional Eu3+. The excitation PL spectra monitored inλ＝480~500 nm with the amount of Tb3+ and that show green emission peak. The fabrication of YAG phosphor thin-film will be useful to improve the emission intensity of the white LEDs in the future.由電解沈積陰極的電位—電流關係圖、Ｘ光繞射分析、SEM 觀察及實驗反應的經驗式我們可以知道要在導電的sapphire（氧化鋁單晶）基材上電解沈積合成燒結YAG 螢光薄膜所需之各類氫氧化金屬，其合適的電解沈積電位為-1.2 Ｖ~-1.5 V，我們利用電化學沈積法可以成功地合成欲燒結成YAG 螢光薄膜所需之氫氧化金屬，將所合成之氫氧化金屬放入高溫爐以1200 ℃高溫燒結4 小時後，依據我們目前以光螢光激發(PL)這些YAG 薄膜的光譜結果，可以成功地得到YAG:Ce(λ=520~530nm)黃光螢光薄膜、YAG:Eu(λ=595~700nm)紅光螢光薄膜及YAG:Tb(λ=480~500nm) 綠光螢光薄膜，證明以新的電化學方法可以成功製備YAG 螢光薄膜，相信這些研究成果未來應用在研發提昇白光LED 發光效能上有極大之助益。