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溶液和溶劑置於同一容器中,當溶質向上擴散時,會形成濃度梯度及\r 折射率梯度dn/dy,且dn/dy 對高度y 的關係圖會呈現隨著高度改變的現\r 象。\r 半徑r 的D形容器,下方置溶液,上方置溶劑,以雷射光照射容器的\r 平面部份時,雷射光沿著法線出射,受折射率梯度的作用而向下偏Ζ距\r 離,a 為容器至屏的距離,得到dn/dy=Z/ar 的關係式;改變雷射光的高\r 度y 可得dn/dy 圖。\r 以硫代硫酸那作實驗,其dn/dy-y 圖為以原始界面為對稱軸,因其擴\r 散係數不隨濃度改變;甘游水溶液的dn/dy-y 圖呈現不對稱,圖形的極\r 大值往甘油方偏,主要係因為甘油的擴散係數隨濃度的增大而減少。\r 我們成功第把不同時間對同一溶液的實驗結果予以模型化,得到的\r dn/dy-y 曲線隨時間改變,並發現該曲線所涵蓋的面積為定值。\r \r The mixing in a vertical column between a pure liquid and a solution produced a concentration gradient, which in turn produced the refractive index gradient. As the solute particles diffused upward into the pure liquid, the gradient was generated by the varying solute concentration. The plot of the refractive index gradient versus vertical position y (dn/dy vs y) is found to be varied with time. A D-shape container of radius r is partly filled with denser solution, and partly filled with solvent which is on the top of solution. When laser beam enters perpendicularly to the flat surface of the container, the outgoing beam strikes the container at normal incidence, and deflected down a vertical distance Z by the refractive index gradient. We can get dn/dy=Z/ar, where a is the distance between the container and the screen,. By changing the vertical position (y) of laser beam, we can get the plot of dn/dy vs y. For a sodium thiosulfate-water solution, the trace of dn/dy vs y is symmetric with respect to the position of original boundary. Since the diffusion coefficient of sodium thiosulfate is independent of concentration. For the trace of dn/dy vs y of a glycerol-water solution, it will no longer be symmetric. A skewed curve which reaches its maximum position is displaced to the glycerol side, because the diffusion coefficient of glycerol is decreased with concentration. We have successfully modeled the time-dependent experimental gradient curves on the same solution. The trace of dn/dy vs. y at different time is found to keep the area constant.
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近年來,溫室效應的話題引起全界的關注,如何節能減碳,幫地球降溫,是許多政治人物、科學家在努力方向。華視電視台曾播放了一個「正負二度C」,看了這個影片,我們更覺得減少溫室氣體排放,找出綠色替代能源的重要。我們居住的馬祖,雖然人少地小,較無舉足輕重的地位,但每一個人若有環境保護的素養,並確實的做法才行,地球一定會降溫的,生物也會快樂活著,沒有物種會消失。 根據維基百科資料,每天的太陽能會有百分之三左右轉成風能,如何有效利用風能是各國努力的目標,我們決定效仿風力發電,期望能喚起世人對綠色能源的關注。本項研究是利用「磁電感應」的原理,研究如何利用風力帶動風車葉片旋轉,產生足夠感應電流,讓LED燈泡發亮。
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Titania Nanotubes for Solar Energy and Catalysis
Introduction The discovery of titania (TiO2) nanotubes suggests vast improvements over extant titania properties. Titania nanotubes are aligned in highly-ordered arrays with a large geometric surface area, making them the ideal material for many applications. However, the mechanism responsible for the growth rates of highly-ordered nanotubes with optimal adhesive properties is not fully explained or understood. Purpose of Research The aims of this project were threefold: to explore the effects of different anodizing parameters on the fabrication of titania nanotubes; to study the photocatalytic activity of the nanotubes; and to deposit gold nanoparticles into the nanotubes. Methodology Nanotube Fabrication: Titanium foil was subjected to potentiostatic anodization with the use of various fluorinebased electrolytes, anodization voltage and duration to compare the effects of different parameters. Scanning electron microscopy (SEM) was used to characterize the nanotube diameter and length of the anodized samples. Photo-electrochemica1 Water-splitting: A PEC cell was assembled using the nanotubes as the photoanode and the samples were anodically polarized in a 1M KOH electrolyte. A potentiostat was employed to control the applied bias and to measure the photocurrent response under light irradiation. Overall photoconversion efficiency (ηc) of the samples was then calculated. Catalyst Support: A gold precursor solution was prepared with HAuC14‧3H2O. Using a novel depositionprecipitation (DP) protocol, gold nanoparticles were deposited on the nanotubes. SEM was used to scan for traces of gold and their locations. Energy-Dispersive X-ray (EDX) spectroscopy was used to confirm the identity of the gold nanoparticles. Data and Discussion Nanotube Fabrication: Preliminary studies found the glycerol/water and glycerol/formamide combinations to be the most promising. In glycerol/water-based electrolytes, higher water content corresponded to a decrease in nanotube length while higher anodization voltage resulted in a significant increase in tube diameter and length. In glycerol/formamide-based electrolytes, higher water content corresponded to a decrease in nanotube diameter while higher fluorine concentration resulted in an increase in inter-tubular spacing. The effects of various fabrication parameters were better understood, contributing to greater control over array dimensions. Photo-electrochemical Water-splitting: A higher anodizaion voltage resulted in a significant improvement in photoconversion efficiency. However, this trend was reversed in chlorine-doped samples, where a longer anodization duration corresponded with better photoconversion efficiency. Doping was found to enhance the photoresponse of the samples, with 6.32 % photoconversion efficiency obtained, suggesting new strategies for light harvesting and a step closer towards commercially-viable solar energy. Catalyst Support: Gold nanoparticles (5-10 nm) were successfully deposited onto the titania nanotube samples. Based on current literature, this was the first successful attempt at depositing gold nanoparticles into titania nanotubes. An EDX spectrum confirmed the identity of the gold nanoparticles. Compared to current catalytic converters, the gold/titania nanotube structure offered a larger catalytic surface area for reactants and the ability to function at low temperatures. Conclusion: By understanding the effects of various parameters on titania nanotube fabrication, the anodization process can be optimized to enable more precise control over array dimensions. High photocatalytic efficiency has also been achieved. In addition, doping is found to improve the photoresponse of titania nanotubes. Gold nanoparticles have been deposited, to our knowledge for the first time, onto the surface and inner walls of titania nanotubes.
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科展作品檢索
?親愛的,誰讓你長高了??(如何證明空氣中氧氣的含量)
經過多次親自實驗發現與文獻資料中利用「悶熄蠟燭」實驗證明「氧氣約占空氣的21﹪(約1/4.76)」有所出入,因為從「悶熄蠟燭」的多次實驗中顯示水位會急速上升,發現利用蠟燭使「水位上升體積」與「空氣中消耗氧氣體積」誤差頗大,更遑論「悶熄蠟燭」可支持「氧氣約占空氣21﹪(約1/4.76)」理論!所以針對:蠟燭數量多寡、火焰大小、空氣膨脹…等因素一一探討,抽絲剝繭找出「悶熄蠟燭」的誤差究竟在那兒?有鑒於「悶熄蠟燭」實驗方式是不準確,因此我們更進一步研發另一新方式,顯示出「水位上升體積=空氣中消耗氧氣體積」,證明「氧氣約占空氣的21﹪」理論。
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貢丸是國人非常喜愛消費的肉製品之一,貢丸製品是以一種畜禽肌肉作為原料,加入鹽和其他配料,利用擂潰機或攪拌缸在低溫環境下萃取出鹽溶性蛋白,做為乳化劑,再與脂肪煉製成一個安定的乳化物,再經加熱使蛋白質凝固製成。為因應國人對健康的需求又能享受傳統美食,便希望能以植物油脂代替傳統貢丸中的豬背脂,經多次的試做,終於成功的做出植物油『健康貢丸』。且經針對本科學生、本校教職員工及社區大眾的品評結果顯示健康貢丸在外觀、脆度、彈性、口味與口感都與豬油貢丸差異性不大,表示利用植物性油脂取代豬背脂所製作的『健康貢丸』在官能品評並不比傳統貢丸差,在總接受度方面較能接受健康貢丸的總人數有 61%,傳統貢丸有 32%,且在喜愛度方面也呈現健康貢丸 59:27 的結果,此結果顯示能接受及喜愛『健康貢丸』的人數比傳統貢丸高。健康貢丸以葵花油製作時最佳且在產品中不會產生令人不快的味道,在貢丸亦可添加蛋白取代油脂,可製成低脂的健康貢丸。
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科展作品檢索
螞蟻也討厭塞車?~探討螞蟻覓食的交通量分佈情形
我們在2004 年7 月號的牛頓雜誌裡,偶然看到螞蟻會分配牠們的交通量這個訊息,但卻沒有多加說明,於是我們決定深入研究。我們設計了較簡單但不影響實驗結果的裝置,在公園蟻窩旁及室內各選定一個放置位置,並確認三種不同種類的螞蟻後便開始進行觀察。我們先選擇了三個地點來觀察螞蟻的生態,再著手設計了適當的實驗,開始進行研究。實驗內容包括:探討吸管(通道)顏色、粗細、易達性對螞蟻覓食交通量分布的影響。持續兩個月的研究,每天定時到三個地方統計及記錄,發現螞蟻會大略遵循著一定的規則分配交通量,例如在一條通道過於擁擠時,螞蟻會大略平均分布在兩條通道中;另一方面,螞蟻會較集中於易達的路徑等。而我們也發現此次的實驗設計,很適合當「捕蟻器」來使用,這可再深入研究。
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線上教學資源
電視上的恐龍化石好炫喔!請問我可以將骨頭埋在土裡,幾十年之後再把它挖出來,以這樣的方法製作化石嗎?
這位小朋友的想法真是不錯!不過要製作化石可不是這麼簡單的事呢!我們現在所見到的這些化石,都是經過幾千幾百萬年的時間才形成的,而且並不是所有埋在地層裡的生物遺骸都能變成化石,不然現在不就滿地都是了。 化石的形成過程,主要是生物死亡後的遺體或生活中遺留下來的痕跡,被當時的泥沙等沉積物掩埋起來,在之後漫長的歲月中,遺體中的有機質分解殆盡,堅硬的部分(如外殼、骨骼、枝葉等)與包圍在四周的沉積物一起經過化石化作用變成石頭,但它們原來的形態、結構,甚至一些細微的內部構造都依然保留著;同理,那些生物生活時所留下的痕跡也能因此存留下來,這些石化後的生物遺體、遺跡就稱為化石。
作者:陳怡安 審查:林明聖
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生物上冊第七章恒定性談到血液中血糖的濃度,通常都維持在一定的範圍以內,過高或過低都會引起疾病。其他,如生物體內水分的調節、定溫動物體溫的調節等,都是生物體內維持恒定性的一些現象。 有關生物行呼吸作用時,呼出氣體的測定,在實驗7─3植物的呼吸作用中,就整個實驗裝置來探討,發現在四十分鐘的實驗觀察過程中,裝置中的漏斗及彎形玻璃管始終都是開放的,而且實驗組與對照組間,結果的比較並不很鮮明,甚至沒有差別。 空氣中氧約佔1/5的體積,氮約佔4/5的體積,其組成分可以說是維持在一定的濃度範圍內(恒定性)。是否可以空氣組成分的恒定性觀念,配合生物呼吸作用釋出的氣體(二氧化碳)的特性,找尋出一種更好而有效的實驗裝置,是探討本實驗的主要動機。
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在物理課本十九章提到磁鐵磁力的大小和磁極所含磁量的多寡有密切的關係,然而一個磁鐵磁量到底有多大,無法測出來,雖然課內將磁量單位定為單位磁極,但單位磁極沒有一定的大小,故引起我們研究電磁磁力來定實際磁量的多少的興趣。
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「大指蝦蛄」為夜行性動物,喜歡躲於洞穴中,故具有背光性與向觸性,牠的地域觀念很強,不會任意離開居所。「大指蝦蛄」在有居所、體型差距越大、晚間、饑餓、黑暗、小空間等情境下,其打鬥與爭奪居所行為會較強,而且打鬥行為強弱與爭奪居所成敗,具有高度相關性。
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本研究動機由於在五年級上學期牛頓第九冊第一單元光和顏色課程,曾做過彩虹的實驗,但我們在實驗時始終無法清楚看到彩虹,於是引起了我們對彩虹研究的興趣。研究過程分四個步驟來進行:分別是(1)利用簡易的噴霧器是否能製造彩虹?(2)不同噴水量的噴霧器在太陽光底下觀察彩虹的清晰度?(3)不同顏色的背景,哪一種背景下所看到的彩虹最清晰?(4)如何營造出在教學上最易觀察到彩虹的方法?實驗結果發現,製造出彩虹是容易的,只要具備噴霧器水量、無雲的陽光,在較暗的背景(黑色最佳)的情況下就可以很容易看到彩虹。另外便於實際教學上可以自己準備一個紙箱子,內部貼上黑色壁報紙,將箱子、觀察者與太陽方位以順時針135 度或225 度所觀看的角度最佳。
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