Self Assembly Mechanism of Water Drotlets
這是一系列關於水蒸氣冷凝為極細微小水珠的長程實驗。其中可以分為下列三個階段:第一階段是基礎實驗。將水氣導入至潔淨的光滑表面上(蓋玻片),觀察水珠冷凝的機制。第二階段是在外加磁場及電場作用下,將水氣導入至潔淨的光滑表面(蓋玻片),觀察水珠冷凝的機制。這部分的實驗推翻了一般「水分子是電中性,在電場或磁場中不受影響 」的刻板觀念!實驗所呈現出來的冷凝水珠,不但有明確的自我組成模式( Self assembly pattern)。並且發現:電場會增速凝結水珠的成長(Aggregation),而磁場則會抑制凝結水珠的成長。第三階段是將水蒸氣導引至超聲波的環境中:我們先將超聲波訊號產生器(變頻、定頻)面向於載台旁,再讓水氣導入至潔淨的光滑表面上(蓋玻片),觀察冷凝水珠的機制。當使用固定頻率超聲波波源,我們發現:在超聲波場中水珠的成長會受到抑制,且成長速率會隨著頻率的升高而逐漸減小。第一階段與第二階段的實驗結果與討論已分別發表於2004 年及2005 年的台灣國際科學展覽報告中,本作品將詳述第三階段。 This experiment explores the basic nature of the condensation of water vapor into droplets on the surfaces of cover glasses. This condensation occurs because of the difference in temperature between the water vapor and the cover glass. The condensation process is observed under a microscope. The growth of the droplets can be described as: nucleation, aggregation (piling up) and coalescence. The growth is irrelevant to surfaces or environments. It is found that the temperature difference of moist air over the cover glass do not affect the nucleation size of the droplets in simple plain surroundings; while the change of flow rate does. In general, the coalescence is speeded up at higher temperatures. Furthermore, the effects of electric fields 、magnetic fields and ultrasonic waves are also studied. It can be observed that the size of water droplets become smaller and grow more uniformly under magnetic fields or imposed ultrasonic waves; also, the aggregation rate is decreased by imposed magnetic fields or ultrasonic waves, and it is increased by imposed electric fields. These effects of magnetic fields 、electric fields and imposed ultrasonic waves might be related to the flow conditions and the vibration of surrounding air in the system. This experiment provides the first step in the understanding of the formation of water droplets and their self assembly mechanism in different environment.
雷射光的研究
這份報告的主題是藉由實驗,來探討雷射光的性質及它的應用,並實際製作利用雷射光原理的小器具。1.證明雷射光是否為單色光:先將雷射光射入不同顏色的玻璃紙,利用光無法穿透不同顏色玻璃紙的性質,以及將雷射光照射三稜鏡,觀察其反射的光線,藉此來證明雷射光是否為單色光。2.雷射光的直進性質:利用彎管或其他不透光物品將光線阻擋,觀察其是否能穿透物品,並且用不透光物質,使我們能夠看出雷射光的軌跡,來證明雷射光的直進性質。3.雷射光的折射與反射:將雷射光射入不同的物質中,觀察其折射角度,來得知雷射光在不同介質中的傳播速率不同,也觀察其是否有反射的現象。4.雷射光的應用:研究運用雷射光製成的物品,如雷射印表機、光碟機等等,並了解其製作原理。5.自行研製雷射小器具:利用雷射光的原理,來製作簡單而獨特、有效率的小器具。The topic of this report is to study the quality and applications of laser by experiments, and actually make a tool by using the principles of laser.1.Prove if laser is a one-color light: By lasing laser through a triangular prism, observe the light it reflected to prove that laser is a one-color light.2.The quality of in-line approach: By using tubes or other lightproof items to block out the light to observe if it can penetrate things, and also let us see the trace of laser to proof the quality of in-line approach.3.The refraction and reflection of laser: Study the differences of refracting angles by lasing laser into different items, to know the speed of laser in different mediums, and also observe if it will have any reflections.4.The applications of laser: Understand how laser products are made by studying them, like laser printers and CD players. 5.DIY laser tools: Make simple but unique and efficient tools by using the principles of laser.
金奈米粒子的合成與其光譜特性
當世界各國正全力朝奈米科技發展,而奈米微粒對環境及人類健康影響與否未明朗之際,有關奈米微粒對人類健康影響之探討是刻不容緩之事。本研究的近程目標是合成金奈米粒子,遠程目標是擬探討金奈米粒子的生物毒性。此份研究主要是描述金奈米粒子的最大表面電漿吸收光譜特性及其最大吸收波長,而金奈米粒子的合成是利用四氯金酸( HAuCl4 )與還原劑—硼氫化鈉( NaBH4 )、聯胺水合物( N2H5OH )或檸檬酸鈉在陽離子界面活性劑的溶液( CH 3(CH2)15N+(CH3)3Br– ,溴化十六烷基三甲基銨,CTAB ) 當保護劑中,利用氧化還原方法直接生成金奈米粒子,並探討四氯金酸的濃度、還原劑的濃度、界面活性劑的濃度及反應溫度,對金奈米粒子生成之影響,另外也探討金奈米粒子的穩定性。有關金奈米粒子的光譜特性則利用UV/Vis 光譜儀測試。研究結果發現在相同的條件下,利用冰浴,以NaBH4 當還原劑所合成出的金奈米粒子之平均粒徑為11.70 nm ,而以N2H5OH 當還原劑所合成出的金奈米粒子之平均粒徑為20.25 nm, 有關金奈米粒子之結構及大小藉由穿透式電子顯微鏡( TEM ) 拍攝出的影像得以驗證。;This study mainly focused on the properties of the maximum surface plasmon absorption of gold nanoparticles and their wavelengths. The synthesis of gold nanoparticles made use of HAuCl4 aqueous solution and reducing agent, through the oxidation reduction method, with reductant, sodium borohydride ( NaBH4 ), hydrazine ( N2H5OH ) or sodium citrate solution in the presence of the cetytrimethylammonium bomide ( C19H42BrN,CTAB ) aqueous solution as protecting agent. The influence of concentration of HAuCl4, reductant, surfactant, and temperature on the synthesis of gold nanoparticles were explored. In addition, the stability of the gold nanoparticles was also explored. Measurements of spectral properties of gold nanoparticles were done by UV/Vis spectrometer.When NaBH4 was used as a reductant, the average diameter of gold nanoparticles was 11.70 nm. When N2H5OH was used as a reductant, the average diameter of the synthesized gold nanoparticles was 20.25 nm. The structures and sizes could be identified by the transmission of electron micrograph (TEM) images.
鄒之風聲-風笛
「風笛」是台灣原住民鄒族的信號用具及祈雨法器,由一條繩子綁一支竹片構成。轉動風笛時,竹片會繞繩子自轉並拍打空氣而發出聲音,並有上下飛舞的現象。風笛產生聲音的原因,為竹片拍打空氣而造成的渦流共振現象;又由於繩子扭力大小及方向改變,使風笛的音調忽高忽低、響度忽大忽小、且竹片會在兩個平面上公轉,而有週期性變化。施力使風笛公轉轉速加快時,竹片自轉速率也變快,使其音調愈高、響度愈大;而繩愈短、愈粗時,竹片的公轉週期將愈短。The wind whistler was once used by Tsou aborigines as a tool for message transfer. It is composed of a string and a bamboo flapper. When swung around, the flapper spins, beats the air, and makes sounds. Moreover, the flapper flies up and down during the revolution. The spinning flapper beats the air, causes the vortex resonance phenomenon, and thus produces sound. As the twist torque and direction change, there is periodical variation in the sound volume, sound pitch, and the movement of the flapper, which orbits up and down at two planes. If given force to speed up its revolution, the flapper,s spinning frequency also increases, which makes the sound pitch higher and the sound volume greater. Besides, when the string is shorter or thicker, the flapper,s revolution period will be shorter.