物理

在實驗用共振法測量聲音在固體、液體、氣體中的駐波聲場，測量各介質中的聲速。研究超聲波在液體中的空腔效應，鋁箔在不同液體受空腔效應所破損面積與時間略成正比，並發現在水與各濃度的洗潔精水溶液中以水的破損效果最明顯。另外利用1.65MHz 高頻超聲波打入水中，因駐波使水有疏密不同產生狹縫，以雷射通過狹縫有光的繞射花紋產生，由干涉條紋可推估駐波波長。利用閃頻共振法研究光彈材料超聲波場，且發展出以肉眼觀測的裝置，由光彈材料的花紋級數與應力研究中，發現花紋級數與應力成正相關，由聲場中的花紋顏色判斷所受應力大小，並發現超聲波不僅有聲場產生並伴隨熱效應，會影響觀測花紋級數。This project began by studying the fundamental properties of acoustic waves, the relationship between its velocity, frequency and wavelength. Experiments regarding the distribution of sound waves in different mediums, and the induction of resonance in solid, liquid and gaseous materials were conducted. Results from utilizing suspending method to confirm theoretical prediction of sound velocity was accurate, and the sound wave patterns in photo-elastic materials were observed. It was also observed that an aluminum foil would be cut in an ultrasonic cleaning device. The effects of different liquids such as water and detergents on cleaning effectiveness were then experimentally determined, taking into account factors such as viscosity. From reference materials, we learned that ultrasonic waves would create Caritation in liquids. Traditionally, sound waves are expected to exhibit only longitudinal waves, yet in this study it was discovered that the residual\r stresses from resonance in photo-elastic materials also indicate the existence of transverse waves.

All Praise be to Allah and Pray and Peace be upon to the Prophet\r of Allah ( Mohammad peace be upon Him )

There are numerous problems caused by today's railway system. This makes Hong Kong a less attractive place to live in. We have to tackle these problems in order to make Hong Kong a better place. Our model can recycle the energy dissipated in the rail vibration, reuse the sound energy produced by the wheels and the rail by a sound energy conversion system, recycle the wind power in the tunnel by a new type of wind turbine, the Wind Power Generator Underground (WPGU), recycle the thermal energy produced by the air-conditioning system of railway stations by a new system, the Thermal Energy Conversion (TEC). When the rail is bent, the magnets attached to it are also pulled down. When the rail returns to its original position, the magnets attached to it are pulled out of the coils. In both cases, the magnets move against a force. The work done to move the magnets against the force is converted to electrical energy. Also, the bottom of the MTR is designed to be curved. The sound waves produced by the contact point of the wheels and the rail directing towards the bottom of the MTR would be reflected to an elastic material which has a number of magnets attached to it and corresponding number of solenoids are fixed on the ground below the magnets. Sound energy can be converted to electrical energy in this case. When a train approaches or passes through the section that the WPGU is installed, wind is generated. The wind forces the wind turbine to rotate at a certain high speed. The turbine transmits the rotation to the coils in the dynamo, and hence electricity is generated. Heat released from the air-conditioner is absorbed by water. The hot water is then pumped into the system. As the hot water in the pipe flows through the evaporator, liquid ammonia inside will evaporate and flow into the electricity generator. Inside the electricity generator, the gas will push the turbine to rotate and hence electricity is generated. The ammonia gas is then condensed in the condenser and flows back to the evaporator. Hence ammonia is used circularly. In order to explain our principle, we would like to introduce the Lenz's Law, an induced current flows in such a direction as to oppose the movement that started it, the Faraday's Law of electromagnetic induction, the induced electromotive force in a circuit is equal to the rate of change of magnetic flux through that circuit, the Law of Conservation of Energy, energy can neither be created nor destroyed, but can transform from one form to the other.

Nowadays, many people are suffering from eye defects and thus eye-glasses play a vital role in their life. On a sunny day, bright light enters our eyes without any adjustment of light intensity, causing discomfort and harm to our eyes. Therefore, sunglasses are right here to satisfy our needs. However, it is very inconvenient for some people who suffer from eye sight problems to bring two pairs of glasses and change them frequently. In order to solve this problem, our Esglasses are designed to combine both glasses together.\r To show the details of the physics theories behind our displays, we would like to illustrate the various components of a liquid crystal as well as the whole structure briefly. The liquid crystal we use is made up of molecules that have no positional order but tend to point in the same direction.

我利用分光光譜儀量測Ga2O3 奈米帶，發現奈米帶之能隙約為4.6eV。接著，在室溫下對這一系列樣品作微觀拉曼散射實驗，首先，我使用三種不同波長之入射雷射光對Ga2O3奈米帶共振拉曼散射實驗，觀察不同波長的入射光對樣品的影響；其次，比較樣品之Stokes 與anti-Stokes 變化；最後，再對樣品作偏振拉曼散射，並比較其相對強度之消長。

As soon as a drop from the same liquid falls to the surface of the liquid, a crown emerges, which is followed by a Liquid Column shortly afterward. In order to measure the diameter of the short-lived crown and the height of the liquid column, we developed two incredible and useful devices for each one of that. After a series of experiments and discussion, we decided to adopt collision and oscillation to illuminate the phenomenon. And the details are in the reports. 液滴活泉：一種碰撞與振盪的交合，也是表面張力與黏滯力的拉鋸。碰撞的同時與 表面張力交柔展現皇冠；振盪的同時與黏滯力以圓形波動吞噬液滴。 望冠興嘆：激起的液體皇冠徑和隆起的液柱高猶如曇花一現，測量技術就簡單設備 而言是窮則思變的契機。 滴滴入扣：滴落小液滴如質點的碰撞，隨著液面的振盪，而終止於波心；滴落大液 滴如多個小液滴集體行動，如聖誕老公公灑落糖果般，爾後激盪擾動迴旋 不已。

無意間在某大學的科學討論版中，發現有人提問了一個關於旗子的問題，但遲遲無人回應。 \r 經過仔細思考這個問題後，想起許多旗幟在空中隨風飄揚的景象，那些旗子似乎有著一定的律動，而這個律動中，風扮演著一個十分重要的角色，不禁使我感到好奇：「風與旗子的擺動究竟有什麼關係？」，恰好有研究的機會，於是就以『旗海飄揚------旗面波之探討』為題目，展開了一系列的研究。