物理與天文學

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。

The phenomenon of pedestrians nowadays is still found. Due to frequent walking, sometimes our legs feel tired and hard to move. This is become the basis for developing tools that are convenient for pedestrians. An easy tool for humans is needed for our activities, especially walking. The Synergy between our hands and feet provides a big and significant contribution to the appliance. Normally, the movement of our hand gets along with its motion with a different side of the foot. When the right foot step, then the left hand is swung forward, and vice versa. The tools can be developed by utilizing a variety of systems. The system includes the tools concentric wheel and axles system, spring system, and pulley system. The concentric wheel and axles system is useful in controlling the rope. Movement on the rope could activate the entire system on the appliance. Wheel that related with the hand is three times bigger than wheel that related with pulley that is applied on foot. Spring system is able to lighten the pressure of the foot with a given upward force, and able to provide downward force when the spring returned to its original position. While the pulley system on the tool used to provide mechanical advantage two times is also useful to lighten the pressure of the foot when walking. The tools can be designed with simple, and able to provide benefits to users. By trial and error, it shows that the tool is able to lighten human’s activity when they walk. The tool can be able to lighten the leg’s load by utilizing arm muscles work. Utilization of the arm muscles which helps to ease the pressure of the foot can provide more benefits. One of them is that it can strengthen the arm strength, so the tool can be used as sport equipment. Utilization of the tool can also be reserved for special people who have difficulty in walking due to an accident or birth with leg defect.

本研究主要探討水滴在高溫鋸齒面上之爬坡現象。實驗中發現在高達四百度的鋸齒面上能形成懸浮水滴，且水滴可持續一段時間而不會立即蒸發，在水平之鋸齒面沿特定方向移動，特別的是，水滴甚至沿著傾斜之鋸齒面向上運動。首先，水滴因受熱在周圍形成一層蒸氣層，阻隔熱的傳遞，使其不會立即蒸發。實驗中改變鋸齒齒廓之兩斜邊的比例，可以驅動水滴往長斜邊所面對的方向運動。進一步實驗顯示，水滴內部的流動趨勢分別為：水滴前端呈順時針方向流動，而水滴後端則呈逆時針方向流動。此外，爬坡中的水滴，其後半部具有較高之蒸發速率，經由設計一個類比的實驗，我們發現，在高溫金屬平面上，透過其平面上的一個凹槽，可以控制水滴前後部位蒸發速率的差異性，也造成水滴向上爬坡的結果。由實驗結果證明，蒸氣壓力與氣體運動對水滴造成的摩擦力為驅動水滴爬坡的力量來源。

人眼所見點光源四週的光芒（我們稱為"星星長角"），夜間瞇眼時所見向上下方向射的特別長的光芒（我們稱之為"炫光萬丈"），這二種視覺中的光學現象無法用相機拍攝，但眼睛卻能夠看見。書上及網路上均無法找到合理的解釋。因此，我們設計了數個實驗來研究這些光學現象的成因。我們發現了星星長角的成因是由光對眼睛表面刮痕的繞射和光對眼睫毛的繞射雙重原因所產生。而炫光萬丈的成因則是光線經過眼球表面淚膜層的部分反射及部分折射所造成。The purpose of the research is to verify possible reasons of some optical phenomenon in human vision, including the star shape of a dot light source and glare upward or downward when one narrowing his/her eyes. These optical phenomenon can be seen by naked eyes but can not be taken photos with a camera. We find no detailed explains which can explain the cause of glare upward or downward on the internet or in books. So we designed several experiments trying to find out the cause of these optical phenomenon . In experiments, we figured out that diffractions by notches on the surface of eyes and eyelashes are both responsible for the star shape of a dot light source. The cause of glare when narrowing eyes is that partial reflection and partial refraction of light take place between boundary of air and tear film and boundary of tear film and cornea. The appearance of glare is closely related to the thickness of the tear film . When we narrow our eyes , the tear film is thicker. The thicker the tear film is ; the longer the glare is .Also, bended extent influence the length of glare. We figured out that the more bended the tear film is ; the longer the glare is.

將水加入溶液上方會造成溶質向上擴散，而造成濃度和濃度梯度的變化。我們使用簡易的實驗儀器算出不同時間各位置的濃度和梯度變化。書上大多假設濃度梯度成鐘型曲線分佈的簡單模型描述擴散過程，但只能用在擴散係數為定值的情況。從實驗或參考資料顯示，擴散係數會隨濃度而變，因此擴散現象常呈現非高斯之分佈，故我們以自己設計的實驗分析溶液在較高濃度時的「非高斯型擴散」，直接測量並計算不同濃度下的擴散速率、擴散係數。研究分子擴散行為理論未完全建立，擴散目前屬於半實驗的科學，此實驗設計與分析方式可供作擴散理論發展的參考。

Purpose of the research Experiments were performed to determine if the frequencies of the colours of pigment differ from the frequencies of the colours of filtered light. The third experiment was performed to determine whether the different colours of filtered light have an influence on plant growth. Procedures Experiments I and II were performed in sunlight and the temperatures of different colours of paper, as well as a white paper underneath different colours of transparencies, were measured by means of an infrared thermometer. The Stefan-Boltzmann equation was used for calculations. Experiment III was performed by placing ten spinach seedlings under each of the Code 40 red, green, blue and black/white shade nets. The control, 10 spinach seedlings, had no Code 40 shade net covering. All these spinach seedlings were grown under similar conditions and harvested after 4 weeks. Data In Experiment I the yellow paper was the only colour that did not perform according to the sequence of the white light spectrum (ROYGBIV). The temperature of the different colours of paper determined the amount of energy that was re-emitted. In Experiment II it was determined that the primary colours red, green and blue, as well as yellow of the filtered light, performed according to the white light spectrum. In Experiment III the spinach plants underneath the blue shade net have the highest average fresh mass (g), as well as the largest average leaf area (cm2), while the spinach plants underneath the red shade net have the lowest average fresh mass (g), as well as the smallest average leaf area (cm2). Conclusions In Experiment I the primary colours of the white light spectrum are red, green and blue. When red and green are combined, yellow is obtained. Therefore the temperature of the yellow paper was lower than expected, because only blue light was absorbed, while red, green and yellow light were reflected. In Experiment II all the colours of the transparencies performed according to ROYGBIV. By comparing the amount of energy of the colours of pigment to the colours of the filtered white light spectrum, it became apparent that there is a difference between the frequencies of the colours of pigment and the frequencies of the colours of filtered white light spectrum.

In this work, techniques to explore the capabilities of multi-walled carbon nanotubes\r (MWNTs) in sorting nanoparticles (NPs) were presented. A droplet of a solution comprising of quantum dots (QDs) with various sizes was deposited on an aligned array of intertwined MWNTs. Photoluminescence (PL) and fluorescence microscopy (FM) revealed that MWNTs were effective nano-sieves that could effectively sort out QDs with a size difference of ~ 2.1 nm.\r Cadmium Selenide/Zinc Sulfide (CdSe/ZnS)core-shell QDs and Cadmium Sulfide (CdS) QDs were used to explore whether chemical properties of NPs affect the sieving capability of MWNTs. Further investigation on the effects of micro-patterning on the sieving ability of MWNTs was also carried out.PL and FM results suggested that micro-patterning could aid in separation of QDs and thus improve sieving capability of MWNTs. With the above findings, QDs emitting different colors as a result of size difference could efficiently be assembled onto the MWNTs en route to three-dimensional architectures with controlled assembly of NPs.\r Together with controlled laser power to remove desired amounts of QDs decorated MWNTs, a multi-colored display could be achieved. Further experiments were also carried out to determine the feasibility of introducing MWNTs as filters for NPs. Dilute solutions containing NPs such as gold colloid was run through these MWNTs filters by gravity. Field emission scanning electron microscope (FESEM) images of the samples showed that MWNTs were successful in trapping the nanoparticles. Explorations into the length dependent effect of using MWNTs as filters, suggested that 300μm MWNTs are better nano-sieves compared to 50μm MWNTs.