天然植物色素與人工染料敏化之太陽能電池
本實驗以吸附染料之二氧化鈦奈米結構電極層為承載基材的太陽能電池為研究對象,旨在增進其光電轉換效率,促使染料有效地吸收光能後造成電荷分離,再經由二氧化鈦傳導帶向外傳出而形成電流,即所謂染料敏化太陽能電池。實驗主軸共分三:1、合成染料N3:觀察吸附度與浸泡時間之關係,發現在18~20 小時電池有最佳吸附;改變電解液濃度,求得最佳電解液濃度範圍;酸化二氧化鈦極板。2、天然植物色素:改變溶劑,得出高極性之丙酮對電池最佳;酸、鹼化植物色素;觀察電池隨著光照時間增加,性質趨於穩定。3、混合色素與染料:此實驗旨在印證不同吸能範圍之染料在極板混合浸泡後,電池吸能帶是否有疊加、擴充的效果,並觀察分開浸泡與混合色素一起浸泡之不同效應,量測IPCE 以玆比較。實驗結果可知,確實對於電池吸光範圍有所增加,且分開浸泡之效果較好。This experiment is mainly about the phtosensitization of Ti02 solar cell, aiming at improving the energy conversion efficiency, promoting the electric charge to separate from TiO2 and spread out through after the dye absorbs light. That is so-called dye-sensitized solar cell. The experiment mainly divides into three parts: 1. Ruthenium(II): Observing the connection between adsorption and dipped-time, find out that solar cell has best to adsorb in 18 to 20 hours; change the concentration of electrolyte; acidification TiO2. 2. Photosynthetic pigments: Change solvent, and get the conclusion that pigment has better adsorption in high polar solvents such as acetone; acidification/basification pigments; observe the changing of energy conversion efficiency while the illumination time increases. 3. Mixed the dye and pigment: This experiment is aim at proofing that the absorption spectrum of soaked-TiO2 may mix after dipped in different dye and pigment. Furthermore, we compares the differences between TiO2 dipped in one mix solution and dipped in several solutions separately, measure its IPCE. According to the experiment, the spectrum of soaked-TiO2 is certainly larger, and dipping in solution separately has better effect to the battery.
台灣珍稀水生蕨類槐葉蘋形態、生活史及生存環境的研究
槐葉蘋(Salvinia natnas)生長於台灣低海拔淡水濕地,目前已列為嚴重瀕臨滅絕的台灣原生物種,為不具有根的植物,是世界珍稀的漂浮型水生蕨類。本研究是探討槐葉蘋形態、生活史及生存環境因子,實驗發現可藉由成熟浮水葉外部形態特徵來區別槐葉蘋與外來種之人厭槐葉蘋(Salvinia molesta);槐葉蘋成熟浮水葉呈橢圓形,葉上毛被物是叢生且分岔,人厭槐葉蘋成熟浮水葉呈雙耳形,葉上毛被物則像打蛋器。當兩物種共存於同一個環境空間時,人厭槐葉蘋以平均11.6 cm2/week 的生長率將槐葉蘋完全取而代之,顯示人厭槐葉蘋之入侵對槐葉蘋生存影響之深遠。經由兩年的槐葉蘋物候觀察,發現3~11 月為抽芽成長期、3~12 月為成熟繁殖期、12 月~隔年2 月為冬枯期及孢子囊果出現期,12 月~隔年5 月為孢子囊果成熟開裂期。其繁衍策略可分為無性繁殖(頂芽及側芽生長)及有性生殖(異配子體交配)。探討環境因子(光照度、氣溫、濕度、水質、水溫、pH 值)分析結果,適合槐葉蘋生存環境的條件為(1)陽光間接照射(半遮蔭,遮蔭度58.33%)、(2)乾淨未受污染的水質(pH 6.5~8)、(3)通風性良好。生長環境符合以上條件即可達到移地保育的目的。Salvinia natans, a floating fern without roots, grows in low elevation fresh water wetlands of Taiwan, and is a critically endangered precious Taiwanese native species. This research investigates the life form, life history, and living environment of Salvinia natans. Our experiments show that we can differentiate Salvinia natans and Salvinia molesta, two easily mixed up species. The shape of matured floating leaves of Salvinia natans is elliptical and smaller, while it is twin-ear shape and larger for Salvinia molesta. Also, they can be distinguished by their leaf hairs. The hairs of Salvinia natans are tufted and separated at the tips, while the hairs of Salvinia molesta form an ‘eggbeater’ shape at the tip. When these two species lived together, Salvinia molesta grew in a rate of 11.6 cm2/week and will replace all Salvinia natans eventually. This shows the profound impact of invasion of Salvinia molesta. From the data of 2-year phenology observation, we concluded that budding took place from Mar. to Nov., growing and reproducing from Mar. to Dec., decaying from Dec. to Feb. (sporocarps were born in this period), and sporocarps matured from Dec. to May. There are two reproduction strategies: sexual reproduction (intergametophytic mating), and asexual propagation (by terminal and axillary growth). After investigating the environment factors (illuminance, air temperature, water temperature, humidity, pH), we found that ex situ conservation for Salvinia natans requires 1) indirect sunshine, 2) unpolluted water (pH 6.5 ~8), and 3) good ventilation.
調幅超聲波解調高指向可聽音之研究
可聽聲有向四周擴散繞射特性,而超聲波具有指向性,改以超聲波載送可聽音訊號後,其載波與旁頻帶均在超聲波範圍,實驗中人耳卻可聽到高度指向性聲音,且調幅解調後的可聽聲衰減率比純超聲波來的低。那為什麼超聲波會解調可聽音?我們以非線性的數學轉換概念,成功以數學推導解釋實驗中所聽到的可聽聲,是由旁頻經由非線性轉換而來的。為了證實空氣中的超聲波有非線性現象,以發射40KHz單頻訊號,除了接收到40KHz訊號外還可接收80KHz訊號,而80KHz訊號振幅,會隨著發射強度而遞增,也會隨著傳輸距離增加至穩定狀態,這所我們從文獻中的非線性理論所吻合。接下來進行調幅超聲波實驗,我們經理論計算旁頻帶強度為頻率響應與調變率乘積的一半,而解調可聽聲的強度為調變率、頻率響應與非線性係數三者乘積,我們也由實驗數據證實理論計算結果,在實驗中,換能器在40KHz有最佳的頻率響應,其非線性係數與所載送可聽聲頻率高低約略成正相關,並且與換能器距離遞增而越遠而增加。此外在提高高指向可聽音輸出功率方面,除製作專屬的放大器、運用方波取代正弦波來載波、配合陣列換能器輸出;在改善音質方面,利用等化器調整訊源頻譜分佈,降低低頻振幅,增強高頻振幅,讓各頻率的原始訊號都能有適當的調變,達到最佳音質。The audible sound has the characteristics of spreading and diffracting. And ultrasonic is directive. We modulate sound into ultrasonic signal. The carrier and sideband are ultrasonic frequency bands. But in the experiment, human can hear highly directive sound. In terms of attenuation rate, AM demodulation sound is lower than pure ultrasonic wave. Why can human hear the directive sound? By using the nonlinear mathematical transform, we managed to explain the audible sound which is transformed from sideband with nonlinear effect in the experiment. In order to confirm that nonlinear phenomena in the air ultrasonic, we launch 40KHz single tone ultrasonic signal. Besides the 40KHz signal, we also received 80KHz signal. The amplitude of 80KHz signal will increase with the emission intensity, and also with the transmission distance to increase its stability. These are consistent with nonlinear theory in the literature. Next we began AM ultrasonic experiment. We calculated the sideband intensity that is the product of frequency response and modulation index. The demodulation sound intensity is the product of modulation index, frequency response, and nonlinear coefficient. We also proved the calculated consequence through the experiment. In the experiment, the ultrasonic transducer has a best frequency response in 40KHz. The nonlinear coefficient has positive correlation with the modulation frequency, and increases transmission distance. To boost the power of directive audible sound, we made an amplifier, using square wave to replace sine wave of carrier, and in conjunction with array transducer output. To improve the sound quality, We use the spectrum-Equalizer to adjust the frequency distribution of the origin signal. The EQ reduces the low-frequency amplitude, and boost high-frequency amplitude, which enables every frequency of the original signal to be properly modulated, achieving the best sound quality.
磁粉探傷原理探討-鐵粉在靜磁場中的受力與運動情形
磁粉探傷過程包含兩個重要的物理現象,其一是磁力線於工作瑕疵處的漏磁現象而形成邊緣磁場,其二是鐵粉顆粒受邊緣磁場的影響而向工作瑕疵處附近聚集現象分別反應出磁場在通過不同介質時所遵循的折射原哩,以及磁場分佈對鐵粉顆粒產生的磁力原理。本研究以電磁通電產生靜磁場,並利用兩電磁鐵間的氣隙來模擬工件瑕疵,因電磁鐵的磁導係數遠大於空氣之磁導係數而造成漏磁場方向機與漏磁面垂直,形成一單純的邊界條件使得邊緣磁通密度的解析解可直接利用馬克斯威爾方程式求得。我們亦導出空氣中的磁通分佈對微小的鐵粉顆粒所產生的磁力公式,發現鐵粉顆粒受靜磁力的大小與該顆粒的體積、磁通密度與磁通密度之梯度成正比,而其方向則與磁通密度之梯度一致,此結論與磁粉探傷過程中,鐵粉向工件瑕疵處聚集的現象吻合。實驗設計採用螢光粉混合鐵粉以獲致明顯的鐵粉顆粒運動軌跡,用數位錄影機紀錄後再擷取影像圖檔判讀其位置與時間之關係,進而反算鐵粉顆粒之位置與所受之靜磁力的關係,以定量的方式證實所推導的邊緣磁場分佈公式以及磁力公式。Two important physical phenomena are observed in the practice of magnetic particle inspection (MPI). The first one is that leakage flux is present in the defect area of the work-piece under inspection. The second one is that magnetic particles aggregate in the vicinity of the defect. These phenomena manifest the theory of flux refraction, which occurs in the intersection area of two different magnetic materials, and the theory of magneto-static force, which is experienced by the iron powder in a magnetic field distribution. Two electromagnets, made of cast steel, are aligned together such that the leakage flux in the air gap forms a fringing field distribution. It is this magnetic field distribution that simulates a defect area in a magnetized magnetic work-piece. Since the permeability of cast steel is far larger than that of air, the direction of the fringing field at the surface of the electromagnets is almost perpendicular to the surface. Such a simple geometry renders an analytical solution to the Maxwell’s equations. The magnetic force of the magneto-static field exerting on the magnetic particle, an iron powder in this case, can be derived by using the principle of virtual displacement. We obtain a formula of magnetic force, whose direction coincides with the gradient of the magnetic flux density and whose magnitude is proportional to the magnitude of the particle volume, the magnetic flux density and its gradient. This formula also agrees with the observation in MPI that the magnetic particles aggregate in the vicinity of the defect.