「天上掉下來的禮物嗎?」—討論十年來大陸沙塵暴對台灣之影響與變化趨?
In recent years, sandstorms have seriously attacked Taiwan day by day. Combining with the observations of Central Weather Bureau and the satellite images of NASA, the study has been collected the data of suspension grain in decades. And the study hopes the sandstorms’ information could be observed in early period. Still it hopes to find out the possible transmission paths in the atmosphere. Then we know how to cope with sandstorms in early time. Sandstorms attack Taiwan frequently in spring, the end of the autumn and the beginning of the winter. Compared with the charts of sandstorms and the satellite images, we could broadly aware that the moving paths of sandstorms are related to the currents and the characteristics of the atmosphere. When El Nino happens, the times of sandstorms attacking Taiwan decrease, and that increase when La Lina happens. According to the results of spectrum analysis, there might be high peaks of a year and six months short period varieties. And low peaks of 2.2 years and 7 months period, tell us that the short period aerosol varieties should be relative with season changes, the long period aerosol varieties may be relative with the El Nino and La Lina period. 近年來,大陸沙塵暴侵襲台灣的情況日趨嚴重影響。本研究中收集了近十年來懸浮顆粒資料,配合環保署空氣品質監測站、中央氣象局所觀測的資料與美國太空總署的衛星影像資料及NASA航空資源實驗室的氣流軌跡回推圖,希望能夠在早期觀測時發現大陸地區沙塵暴訊息,和沙塵暴所帶至大氣中的懸浮顆粒可能傳輸路徑。發生沙塵暴侵臺事件的季節,主要在春季及秋冬兩季交替期間發生的次數為最多。由地面天氣圖表、氣流軌跡回推圖及美國太空總署的衛星影像進行綜合比對之後,可大致瞭解大陸沙塵可能的移動路徑與大氣環流特徵有關。 聖嬰現象(El Nino)發生時,侵襲臺灣的沙塵暴次數會減少。在「反聖嬰現象」(La Lina)發生時,侵襲臺灣的次數相對增加。經由頻譜分析中得知,懸浮顆粒高峰期的變化有1年期及6個月變化趨勢,懸浮顆粒低峰期的週期變化有2.2年與7個月的變化趨勢,顯示短週期大氣懸浮顆粒變化應與季節變化有關,長期性變化或許與聖嬰反聖嬰週期有關連。
鈦鈦相傳-以新穎水熱-化學電池法製備二氧化鈦
In our experiment, the novel hydrothermal-galvanic couple method is used to produce nanostructured TiO2 thin film. Compared with the traditional hydrothermal method, whose process is conducted under high temperature and high pressure, the hydrothermal-galvanic couple method is a thermally and electrochemically driven process. The titanium atom is gradually oxidized on the surface driven by potential difference, and eventually become nanostructured TiO2. The advantages of the hydrothermal-galvanic couple method are numerous: they are simple, environment-friendly and energy-saving. Experimental parameters include time, concentration and types of solution. The hydrothermal method is used for comparison. By the cross-section and surface pictures of Field-emission scanning electron microscopy (FE-SEM), we can clearly observe that there is obvious change on the titanium surface, along with increased thickness and altered surface structure. The film of hydrothermal-galvanic couple method is thicker than that of hydrothermal method. Thickness increases with time and concentration as well. Both the hydrophile and decomposition of methylene blue examination indicate that the product on the surface contains photocatalyst-like feature.我們利用新穎水熱-化學電池法製備奈米級二氧化鈦薄膜。相較於一般傳統水熱法高溫高壓的製程,水熱-化學電池法結合了熱能與化學電能,讓鈦原子在電位差的驅動下於表面逐步氧化,最終形成奈米級二氧化鈦粒子,具備簡易、環保、省能的優點。實驗參數包括時間、濃度、溶液種類,並以水熱法作為對照組。由FE-SEM 橫截面圖及表面圖可清楚看到鈦的表面有明顯變化,膜厚增加、表面結構改變;以水熱-化學電池法所得的薄膜明顯較水熱法厚,而其厚度隨著濃度及時間的增加也有增加的趨勢,由試片親水性測試與亞甲基藍吸光度測試,皆顯示試片的表面產物具有類似光觸媒的性質。
漩渦之美
我們常可以在自然界中發現漩渦的存在,但其存在的形體與性質也不盡相同,為了研究漩渦的結構與形體,筆者分析出多種會對漩渦產生影響的因素:開始放流的水而高度、放流洞口大小、有無破壞漩渦結構的阻礙、單孔落流漩渦與雙孔落流漩渦、還有流體的黏滯度對漩渦的影響, 但漩渦是一個不斷改變的流體,非常難以觀察,且自然界的漩渦也不是說出現就出現,所以必須設計一個簡易實驗器材來觀察,並用數位攝影機紀錄下來,再慢慢分析,而我們也可以在這個實驗中了解漩渦的結構,和體會到漩渦所表現出自然界的力與美的一面。‧We can always find in nature of different swirl’s forms and properties. To study the swirls, we analyzed such factors, as the beginning water level, the size of the hole, the presence of obstruction that will destroy the structure of swirls, differences between single-hole-swirls and twin-hole-swirls, and the viscosity of fluid. Because swirls change all the time, it is very difficult to observe. We designed a device .The procedure was recorded with a digital video camera and analyzed it. The study helps us understand the structure of swirls and admire the beauty of swirls.