水滴奇遇記-蓮花效應的真面目
Lotus self-cleaning effect arises because the leaves have the superhydrophobic surfaces. When rain falls onto a lotus leaf, water beads up as a result of surface tension. The water drops promptly roll off the surface, taking every dirt with them. This phenomenon is called the lotus effect. With the aid of a light microscope and an Environmental Scanning Electron Microscope, we observe and describe the morphology of the leaves of Nelumbo nucifera in detail. We successfully observe the real interface between air, water droplets and the papillae of a lotus leaf, and find the evidence of a composite surface that is formed by epicuticular wax crystals and air. These observations improve our understanding of the two-level composite surfaces that are formed by micro-scale papillae, nano-scale epicuticular wax crystals and air. We try the method of using the critical angle of a static drop beginning to roll on inclined surface to evaluate the self-cleaning ability. We then find out that it may be a more precise criterion compared to using the static contact angle for the evaluation of the lotus effect. Literature review shows that the earlier investigation lacks the height(H) and interval(I) of the projections on the lotus leaf surface. A close relationship between the self-cleaning property and the H/I ratio is found. In this study, we present the experimental data of the height and interval of the projections on four different species of plant leaves that all have lotus effect, which may be of great help to technological applications. 蓮花效應是指蓮葉表面具有超疏水性與自我潔淨的能力,當雨水落在葉面,因為表面張力的作用形成水珠,水滴迅速滾離葉面,把灰塵一起帶走。本實驗以光學顯微鏡和環境式掃描式電子顯微鏡觀察蓮葉,詳細描述其表面形態,成功的發現空氣、水滴和蓮葉乳突真實的接觸界面以及表面蠟和空氣構成複合表面的證據。實驗結果可以使乳突、奈米表面臘質和空氣構成的雙層次複合表面更容易被了解。我們嘗試以水滴傾斜滾動臨界角來評估自潔能力強弱,實驗結果比傳統使用靜止接觸角更為準確。表面高度和間距的比值與蓮花效應有很大的關係,查閱文獻顯示蓮葉缺乏這些資料,本研究提出四種有自潔能力的葉子的實驗數據,這些數據應該對科技應用有很大的幫助。
Self Assembly Mechanism of Water Droplets
這是一系列關於水蒸氣冷凝為極細微水珠的實驗。其中可以歸納為三大部分,第一部分是基礎實驗,將水蒸氣導引至親水性介面上,觀察冷凝水珠的結構。雖然看似簡單平常,但是卻發現:不同溫度的水蒸氣,其冷凝最初始的細微珠粒,尺寸相同;爾後溫度高者,堆疊速率較大,以至於最後同時呈現的水珠大小不一,尺寸不同!
第二部分,是針對冷凝水珠自我組裝機制的探討。實驗是將水蒸氣導引至密度小於1的高分子溶液上,並藉由揮發性溶劑快速揮發,將水珠粒「分層保留」以便更深入了解「解構」後的水珠群聚機制。在這組實驗中得到兩張有趣的圖片:
在討論時,我是從對流機制切入,嘗試解構上面兩張圖。
第三部分的實驗,是將水蒸氣導引到磁場及靜電場上,觀察冷凝的機構。這部分呈現出來的結果,推翻了一般「水分子為電中性應該在電場與磁場中不受影響?」刻板觀念,實驗呈現水分子:不但在電磁場上不易長大同時也有固定的散佈模式(assembly pattern)。同時也觀察到:水分子在正電場形成的凝結水珠較為均勻,在負電場則表現出較大親水性特質。這部分的實驗對日後研究細胞膜上水分子通道應有助益。
I have tried to ask a famous math professor if he can create a formula describing the ordered array of water droplets. “Then, I should study Physics first!” He said. Condensation is the thing we live with, being found everywhere, passing without notice. But we never know when it dose start? By coalescence, water droplets grow bigger, but are not round again. We used the polymer film as template and designed the solution lighter than water, so the minute droplets will sink to the bottom and layer by layer. After seconds we may have multilayers of ordered array. This experiment presented here is actually the diary of the growth of water droplets through condensation, upon volatile fluid, magnetic field and electric field. Through convection, it discusses the self assembly mechanism of water droplets and peep into the uniformity of the size of water droplets. In this experiment, convection and magneto-electric force did play important roles in the self assembly mechanism of water droplets. The topic is mostly concerned as we are surrounded by magneto-electric waves in today’s world. This is the first step in discovering the homogeneous state of water droplets, providing insights into the self assembly mechanism of water droplets with nano sizes.
蜘蛛數
We understood the definition and meaning of spider number by reading〝Wonders of Numbers〞. It interested us so much. So, we took further step to study the situation of extreme value when the gap sometimes lie on the line and sometimes on the circle or even on both. That is to say, we explored the relation between spider number and the gap when the spider number is maximum or minimum. New research for the application of spider number involves several directions. First, we design a new game called〝Stepping Land Mine〞with the rule of spider number. Give you a net with several hidden gaps, trying to find the right positions of gaps. Second is the further result for a different type of net about regular n-polygon. Third is a tactic for a net with destroying of the strategy points. In this situation, the gaps amount on the circle and on the line are fixed. At the same time, consider the situation of circles and lines designing the tactic of placing the gaps to attain the maximum of the destructive effect. 在本文中我們定義一個蜘蛛網上的蜘蛛數,若在蜘蛛網中加入缺口後,會影響蜘蛛數的大小。我們探討蜘蛛網上的缺口,該如何分配才能夠得到蜘蛛數的極值(最大值及最小值)。先觀察一直線和圓上缺口如何放置蜘蛛數有極值,再探討許多條直線及圓上的情況,進而推展至許多同心圓及通過圓心的許多條放射線的缺口,該如何放置,蜘蛛數才會有極值發生。
二次函數上正三角形建構之研究及探討
在拋物線上置掛正三角形看似簡單,其實不然。本篇文章研究在二次函數的各種不同情況下,可做正三角形的分佈以及其個數。
1. 在一條拋物線上時,最多只能作正三角形。
4. 在三條對稱軸相等的拋物線和共頂點開口大小不同之拋物線上,本篇文章證明一定能找出正三角形落在它們之上。但由於最多有四個分界點,要解四次方乘組過於繁複,於是本篇文章對分界點作了一些估計,找出了分界點的極限值。
5. 本篇文章證明了對於給定的正n 邊形,存在一1 元n-1 次方程式可以通過它所有頂點。
Building a regular triangle on a parabolic curve looks easy . In fact , it doesn’t . This Article researches regular triangles distributions and its numbers in different conditions.
1. On one parabolic curve can only build regular triangles , squares and other regular polygons can’t be built.
4. For three parabolic curves which has same symmetrical axis or three concurrent parabolic curves, we prove that it can build at least one regular triangle on them .But because it can have at most 4 boundary points, to solve quartic equation is to complicated. So we do some estimation of boundary points, and find out some limits.
5. This Article prove that for given regular polygons , there exists a one dimension n-1 orders equation can pass all its apexes.
奇妙的三維世界
本實作以光學全像術為基礎,拍攝出三維立體的影像。內容主要為分別製作「穿透式」全像片、「反射式」全像片及「彩虹」全像片等三部份。其中,在反射式全像片中,嘗試以不同數量的光束來拍攝。發現以單光束法拍攝出的全像片比較容易成功,但重建影像的視角與效果都不如雙光束拍攝法來的好。在拍攝彩虹全像片的過程中我們令狹縫為變因,做有加狹縫與未加狹縫的實驗,實驗發現效果不同。並以改變狹縫的角度、方位,來觀察底片的變化。最後,觀察出豐富多樣的彩虹變化型態。全像片可重建拍攝的物光與參考光,並顯現拍攝物的三維狀態。可應用於信用卡、紙鈔防偽,廠商標籤,附加商品(如鑰匙圈、貼紙),廣告看板等,用途廣泛。 The purpose of this project is to construct the 3-dimensional images utilized optical holography. The holograms we made can be categorized into three main types: transmission, reflection and rainbow. In reflection hologram, we have tried to construct the hologram by the use of different number of light beams. It could be found that the reconstructed image of the hologram formed by a single beam is better than those of the hologram formed by two beams. However, the field of view and image quality of the two-beam hologram was better than those of single-beam hologram. In rainbow hologram, we varied the orientation and position of slit to investigate the quality of the reconstructed images. The reconstructed images displayed rainbow image diversity. In application, the holograms can display three-dimensional images by reconstructing the hologram. In addition, the holograms are in widespread applied in security applications of credit card、banknotes、labels、stickers etc.
「膠」流電-黏度及外加電壓對電解質溶液離子暫穩態通道之影響
在本次實驗中,我發現膠狀電解質溶液中的帶電離子,會因為離子團的熱運動,和電偶極的庫倫吸引力 (electric dipole) 的交互作用下,使溶液的I-V curve (電流-電壓曲線),具有類似磁滯曲線(Hysteresis curve) 的效果;而膠狀溶液之濃度越高,電解起始點的對應I-V 值也越大。此外,白金電極與銅箔電極的距離若改變,也會使溶液的I-V curve 變的不一樣。另一方面,我也發現,在給予膠狀電解質溶液一緩慢外加的電壓或衝擊電壓並持續維持此一定額外加電壓時,會因為該溶液的黏度持續增高、帶電離子濃度增高且反應不斷變化下,而使該溶液的對應電壓,形成一重複出現「先降-後升-再降」的震盪現象,且電壓值節節升高。最後,我利用掃描式電子顯微鏡(SEM)及能量分散光譜儀(EDS)觀察銅箔電極之表面變化並分析其上之化學組成,藉此嘗試解釋上述這些有趣的現象。In this experiment, with the interaction of the heating action of ionic atmosphere and electric dipole, I find that ions in the gel make the I-V curve in the colloid electrolyte liquor show up with the effect similar to Hysteresis curve. The higher concentration of the colloidal solution, the bigger value of I-V at the initial electrolysis reaction was found. Furthermore, the shape of I-V curve is dependent on the distance between platinum electrode and cupper electrode. On the other hand, I find that when I apply a gradual extra-voltage or a fast extra-voltage to the colloidal electrolyte solutions and then maintain to a fixed value, this will make a unique ‘two peaks’ state oscillation of corresponding voltage. The reason is owing to the climbing viscosity and ion concentration in the solution. With the methods of scanning electron microscope (SEM) and energy dispersive spectrometer (EDS), I observe the change and analyze the components of chemicals on the surface of the cupper electrodes. Finally, I present the interesting results and try to interpret these phenomena.
A study to find out suitable colour to control pests of chilli plants using a colour trap
Chilli (Capsicum annuum L.) is one of the most important condiment crops in Sri Lanka. The main constrain in chilli cultivation is the Leaf Curl Complex (LCC) which reduces the quality of the pods as well as the yield. Many researches have been proven that the problem can be controlled by Integrated Pest Management (IPM) practices. Colour sticky trap is one of the mechanical methods in the IPM package which reduces the pest population successfully. Mainly three colours, namely blue, yellow and white have been identified as suitable colours for traps all over the world. This study was thus, conducted to find out the most effective colour for sticky traps to control chilli leaf curl complex in the Intermediate Zone of Sri Lanka. Traps were prepared from wooden plates of 30 x 25cm in size and the colours were applied in both sides of the plate. Both colourless and odorless vaseline was used as the sticky substance. These blue, yellow and white sticky wooden plates (traps) were fixed in 1m height from the ground level and they were used as the treatments. Six pots with 2 plants each of the variety ‘KA-2’ were used in a treatment and three replicates were sited for the experiment. All the agronomic practices were equally done for all the treatments. Number of trapped pests associated with the LCC was counted in 4, 6, 9 and 12 weeks after transplanting. The number of leaves affected by the pests in a canopy was counted in 7, 10 and 12 weeks after transplanting. The number of damaged green pods and the pod weight were taken at harvesting. The mean values of the number of pests trapped in white, yellow and blue colour traps were 162, 160 and 38 respectively. The percentages of damaged leaves in a canopy at 7, 10 and 12 weeks after transplanting in the blue trap were 89.07, 98.00 and 100.00 respectively. Those values in the white trap were 87.37, 98.90 and 93.29 and in the yellow trap were 69.03, 87.26 and 82.26. Percentages of damaged green pod weight in the blue, yellow and white treatments were 66.63, 47.06 and 45.65 respectively. These results suggest that yellow and white colours are more effective in sticky traps in pest controlling to control chilli leaf curl complex in the Intermediate Zone of Sri Lanka. Further studies are required to confirm the results.