全國中小學科展

依國際科展年度查詢

工程學

電離轉輪

This research primarily aims to observe how does the electric work, why does it work and the relationship between the surrounding circumstance and the repulsive torque. The electric whirl is made of an enameled wire bent into right angle with sharpened ends. When an AC high voltage is applied, the electric field intensity around the whirl ends is strong due to the small curvature radius of the ends. The molecules in air at both ends are ionized. This cause the phenomenon of point discharge. The positive and negative ions produced by alternating current forms AC ion wind, and produce a torque to make the whirl rotate. The object of this experiment is to observe the relationship between the surrounding circumstance and the torque repulsion. We design an apparatus to measure the angular velocity of the rotating whirl. We also calculated the kinetic energy of the whirl and the work done by the torque. The repulsive torque can be obtained by Work energy theorem. Result: (1)The angular velocity of the electric whirl is direct ratio to repulsive torque. When we want to find out the relationship between the manipulate reason and the repulsive torque, we can just compare the angular velocity with the manipulate reason. (2)The angular velocity of the electric whirl is only related to the peak voltage, and it does not make difference whether we apply AC high voltage and DC high voltage. (3)When the humidity is over 68%, the electric whirl cannot function normally. (4)Under the low-pressure circumstance, the electric whirl will rotate with glow discharge and the angular velocity will decrease to zero gradually.本實驗是探討電離轉輪的性質、原理與周圍環境的關係。「電離轉輪」為漆包線兩端折成直角並磨尖而成,接上交流高壓電源時,其尖端曲率半徑小,電場強度相對大,會游離尖端附近的空氣分子,產生尖端放電的現象,而交流電交替產生的正、負離子會形成交流離子風,並產生轉動力矩,使轉輪轉動。我們設計一個裝置,使其能偵測轉輪轉動的狀況,運用測得數據計算出轉動時的動能和作功狀況,套用功能定理便可求得轉輪通電時產生的斥力矩。實驗結果顯示(1)轉輪的角速度和尖端斥力矩成正相關,所以當我們想得知尖端斥力矩和實驗操縱變因的關係時,只要比較角速度和操縱變因就可以了,這簡化了原本繁複的計算和冗長的數據處理過程。(2)轉輪的角速度只和峰值電壓有關,和直流或交流沒有直接關係。(3)轉輪在超過溼度68%之後,就不會正常運作。(4)在低壓條件下,轉輪轉動時會伴隨淡紫色的輝光放電(glow discharge)現象,而抽氣塔中與轉輪尖端最接近的一點,也就是電場最強的一點,會和尖端同時產生光芒,相互輝映。

奈米科技材料新發現-氮化鉻

利用陰極電弧蒸鍍各種薄膜,如:類鑽膜(DLC)、氮化鈦膜(TiN)、氮化鉻膜(CrN)、氮化鋁鈦膜(TiAlN)以及先披覆上一層氮化鋁鈦膜(TiAlN)再加上類鑽膜(DLC)的合成膜等。這些薄膜現在已經被廣泛的應用於各種刀具、模具的表面處理之中。本研究主要在探討高速鋼鍍上氮化鉻膜(CrN)之後,對於硬度、磨耗性質的改變,以及觀察氮化鉻膜(CrN)表面結構之組織。 在研究中我們運用陰極電弧蒸鍍系統蒸鍍氮化鉻薄膜,分析上運用SEM來觀察薄膜表面結構組織,以及運用洛氏微硬度機來觀察試片的硬度,另外還有使用磨耗試驗機來進行磨耗測試。以上這些測試總括來說都是在得知性質有無實際上的改變,而這些實際上的改變對於蒸鍍之後的模具或刀具都能夠大幅的提高使用的壽命。 We evaporated different kinds of thin films by using the anode of the electronic arc, such as DLC (Diamond-Like Carbon), TiN (Titanium Nitride), CrN (Chromium Nitride), TiAlN (Titanium Aluminum Nitride), and synthetic films of covering TiAlN and DLC. These thin films have been used widely in processing the surface of a variety of cutters and moulds. The purposes of this research were to investigate changes of hardness and abrasion and to observe the organization of the surface structure of CrN after High-speed steel evaporates CrN. In this study, we use the system of the anode of electronic arc to evaporate CrN. Besides, SEM is used to observe the organization of the surface structure of the thin films and Rockwell Micro-hardness Test Machine is used to investigate hardness of testing samples. Moreover, we use Abrasion Tester to test abrasion. These tests are taken to lead to a better understanding whether the quality really changed. These changes of evaporated moulds or cutters would extend their frequency of using.

Door Security

奈米使你變美了!-奈米二氧化鈦在化妝品上的應用

奈米的科學與技術將是21 世紀所要探討的方向。在了解奈米粒子的表面效應、小尺寸效應、量子尺寸效應、宏觀量子隧道效應後,發現其應用甚廣,諸如再生物、醫學、環境、國防、工業產品等方面,都將佔有很重要的地位。我們主要是利用溶膠-凝膠法來製造二氧化鈦奈米粒子,並了解二氧化鈦奈米粒子可吸收紫外線及光催化反應,將廣泛應用電子、紡織、塑膠、橡膠,空氣淨化及廢水處理方面。本實驗將利用二氧化鈦的吸收紫外線特性,來研究其應用在化妝品上面。The science and technology of nanomater will be the direction we will explore in the 21st century. After understanding surface area effect of nanometer particle, Small size effect, Quantum effect, and Macroscopic quantum tunnel effect, we can diswver the application is very far-fluing. For example:biochemistry, medical science,eneironment,national defense and industrial products,will devine a very important position.We mainly use sol-gel method to produce U-TiO?,and understand the absorption of UV and photocatalysis,plastics,mbber,purging air,and dealing with effluents.This experiment will use characteristic of absorbing UV of U-TiO? for researching the application of cosmstics.

Fast Fabulous Flush

Water is very vital in our lives as we cannot live without it. However our world is now facing a serious problem. Owing to the increasing population, water resources are scarce. In recent years, we can see that droughts have been affecting millions of people around the globe. In the meantime, people in developed countries have been wasting huge amount of water for flushing the toilet. According to the US Environmental Protection Agency, 30% of household water goes toward flushing the toilet. Countries like China, US, Canada and UK are still using fresh water in flushing, consuming 190 million L of fresh water every day, not to mention the energy needed in pumping the water. In fact, it is not necessary to use so much water to flush away substances like tissue, hair, urine etc. The water we used is far more than we need. However, as we cannot control how much water is used when we flush, all water in the cistern is flushed away. Realizing the seriousness of water shortage and wastage in flushing, we tried to invent a device to conserve water by controlling the amount of flushing water used. Firstly, we study the principle of normal flushing system so as to understand why flushing cannot be controlled. Then, we tried to think of ways to control flushing. We have tried various methods and materials. After the 6-month testing and modification, we successfully invented Fast Fabulous Flush. It is a device which can be fit into existing cistern to conserve water. With our invention, users can control the amount of water flushed according to needs, so as not to waste unnecessary water. Our invention costs a low price which is no more than 2 US dollar. Also, it can be fit into existing cistern within 3 minutes with simple installation process. Most importantly, flushing water can be conserved effectively. It is estimated that around 200L of water can be saved per household every day.

讓瓶塞隨心所欲

這是一種可在膨脹狀態及未膨脹狀態間轉換的膨脹收縮瓶塞。本設計之瓶塞包含一彈性橡膠之塞座及一剛性塑膠之旋轉控座。該瓶塞在未膨脹狀態,可將瓶塞置於平口內將瓶塞順時針方向旋轉90度使瓶塞由未膨脹狀態轉換至膨脹狀態將瓶子密封;欲開瓶時將瓶塞逆時針方向旋轉約90度使瓶塞由膨脹狀態轉換至未膨脹狀態,可輕易將瓶塞從瓶子內拉出。根據顧客之需求設計瓶塞並選定適當之塑膠材料以製作旋轉控座及適當之衛生橡膠以製作塞座,依廠商提供塑膠及衛生橡膠之特性資料做有限元素分析預測橡膠元件受撐大之變形量,進行加工與製造印證分析之結果,與預期目標有相當的差異,故製作簡易之試件進行探求塞座內縮量與瓶塞膨脹量之關係, 探求瓶塞膨脹量與瓶子所能承受的壓力之關係,進而逆向設計瓶塞之塞座內縮量。 This is a kind of bottle plug that can change at the situation of swell or unswell.The design of this bottle plug includes a rubber plug and a rigid plastic controller that can revolve around. We can put the bottle plug at the top of the bottle and rotate it 90° c.w., the bottle pug will be at the situation of swell and then seal up the bottle. If we want to open the bottle, we just rotate 90° c.c.w., and the bottle plug will be at the situation of unswell and then we can pull the bottle plug out easily. I design this bottle plug according to the need of the customers; choose the certain plastic material to make the rigid plastic controller, and the properly rubber to make the plug; analyze and predict the amount of deformation by Finite Element Method in accordance with the characteristics of rubber and plastic supplied by the factories. However, the result and the expected result are quite different. In order to solve the problem, I make an easy sample to search for the relationship between the contraction of the rubber plug and the swells of the plastic controller and also the relationship between the swells of the plastic controller and the pressure that the bottle can endures. Then I design the contraction of the rubber plug on the base of the result of the experiment I made above.

以彈性體模型評估心血管疾病之新方法初探

我們根據物理學的彈性體振動模型發現:主動脈硬化程度可由測量主動脈相對於心臟運動的延遲時間分析得知。我們除了由樣品之超音波影像分析驗證此一觀念之外,還用一自製模型進行實驗,模擬血管厚度對延遲時間的影響,實驗結果與理論相吻合,證實了彈性體模型之可靠性。在診斷方面,此方法可用目前臨床使用的心臟超音波儀直接進行測量,使得它具有方便、普遍的優點;而且可由體外的胸前超音波掃描(TTE)進行觀測,具有非侵入性、免除受測者的不適及避免副作用,此外,能定量分析、早期診斷、鑑別度高也是此方法重要的優點。According to the elastic oscillation model of physics, we found that the aorta stiffness could be obtained by measuring the delay time of the aorta relative to the cardiac motion. The idea was confirmed by an analysis of the echocardiograph images of several samples. A home-made mechanical model was also employed to simulate the effect of cardiovascular thickness. The experimental results fitted the theory very well, verifying the feasibility of the elastic oscillation model. This measurement could be carried out with the conventional echocardiography instruments, making it convenient and common. Furthermore, the delay time could be measured with TaransThoracic Echo (TTE) instead of TransEsophadeal Echo (TEE). This non-invasion can avoid patients’ discomfort and side effect during medical process. The quantitative measurement also enables that the diagnostics can be progressed in advance.

以珊瑚蛋白及光頻轉換分子改善太陽能電池效率之研究

能源危機日益嚴重,開發再生能源成為當務之急。在諸多的再生能源之中,太陽能最易於使用,且可源源不絕的不斷取得利用。但目前太陽能電池的效率始終不高。其中重要的原因是太陽本身的頻譜多為短波長,並不適合絕大部分頻譜響應較佳,多為長波長的太陽能電池。目前改善效率方式,多為改變太陽能電池的頻譜響應以配合太陽之頻譜。本研究提出反向思考的概念,藉由頻譜轉換的方法,改變照射在太陽能電池上的太陽光頻譜,以提升太陽能電池的效率。本研究利用一種珊瑚礁的螢光蛋白質(DsRed)以及人工合成的螢光染料(Cy-5)最為本研究的頻譜轉換的材料,加於低成本,目前市場佔有率較大的單晶矽太陽能電池上,經由理論與實驗的結果顯示,增加的發電效率約為3~5%,證實利用頻譜轉換的概念確實可以提升太陽能電池的效率。Energy crisis has become more and more serious in recent years, which makes recycled-energy development is a must. Among different recycled energies, solar power has two advantages, that is, easy-to-use and endless supply. However, the conventional solar cell makes poor use of the solar spectrum because the solar spectrum is mainly composed of short-wavelength, which can’t fit to most of solar cells which is more sensitive to long-wavelength. Currently, the major method to improve the efficiency is change the function of spectral response, such as concentration lens, tracking devices, and antireflection coating. Up to now, no one notices the possibility of changing solar spectrum yet. This research provides an insight into this issue. Instead of changing the function of spectral response, I changed the solar spectrum, which irradiates solar cells through spectrum conversion to improve solar cells’ efficiency. This research uses one kind of coral fluorescence proteins (DsRed) and one kind of artificial fluorescence dyes (Cy-5) as the materials of spectrum conversion. Then coat them on the low-cost and high-market-share mono-crystal-Si. According to the theories I researched and my experiments, the improvement of the efficiency is about 3~5%, which proves it is actually useful to elevate the efficiency of solar cells through spectrum conversion.

Pulse Jets

I made this jet engine to demonstrate how a pulse jet works and to show were the fundamentals of powered aviation all began. I also made this project to gain more knowledge, due to my interests in engineering and turbines. I would also like to measure the thrust of this model in the future. And hopefully this might inspire other people to use this type of engine in their model aircraft.

Waste Not,Want Not

Many people in South Africa still use open fires for cooking. There is a\r large amount of wasted heat lost by four methods of heat transfer:-\r radiation, convection, conduction and evaporation.\r I constructed a vessel that would reduce heat loss, and focus the heat\r emitted from a fire onto the bottom of a pot. I used materials that were\r cheap and easy to obtain, so that those using open fires would be able to\r construct similar vessels to save energy and reduce pollution.\r The vessels were made up of a standard wire mesh frame that was\r surround by trial coverings, namely tin foil, asbestos rope, industrial foil,\r papier mache, ceramic, and 2 ceiling insulators.\r 5 mls of methylated spirits was burned in each vessel. The temperature\r gain of 100mls of water in a standard pot was recorded. 5 trials on each\r vessel were performed. 2 groups of vessel were found. Those that\r produced high temperature gains, burned quickly, and produced a large\r amount of soot deposits on the pot, and a second group that did the\r opposite.\r I compared the rate of heating from my best vessel to that of a stove as\r well as a microwave oven. Heating from the vessel was faster than that of\r the stove, and slightly slower than the microwave.\r I measured the heat emitted from a fire in a three-dimensional pattern and\r found that the maximal heat was some distance above the flame.\r From these results I devised 12 guidelines that would minimize the\r energy need, and pollution produced, when cooking on an open fire