物理

An orbital angular momentum (OAM) sorter concept was designed for high-speed data transfer. The OAM of a light beam known as an optical vortex can exist in one of an infinite number of states and may be used to carry information. The augmented alphabet of states carries the potential to increase date transfer speeds over conventional binary (0 and 1) methods. A vortex generator, or OAM encoder , was constructed from a slit cover slip functioning as an adjustable spiral phase plate, and a vortex analyzer, or OAM measurer, was created using a transparent print of a computer-generated hologram. The two components were then incorporated in an OAM sorter concept that that employs a novel combinatoric method for sorting data. The vortex generator and analyzer created were inexpensive simpli-fications of previous devices and have the potential to increase the alphabet of transmission states several thousand times over binary methods if implemented in the OAM sorter concept.

Our traditional bow is a kind of horn bow which appeared at the side wall in the sepulcher\r around A.D 600. A lot of traits of the horn bow have been handed down to us in an\r unwritten form. This is the reason why I would like to research and investigate the several\r potential capacities in the field of Physics, such as structures, materials and efficiency.

One afternoon, a photography enthusiast, Mr. Cheung was holding some photos, completely absorbed in the fond (but ancient) memories of his honeymoon in Cairo. The badly-yellowed photo prints reminded him of every sweet and romantic moment of the “good old days”. He was soon rudely awakened when Mrs. Cheung shouted, “Honey dear! I was told that high-tech is ‘in’, and the single-lens reflex camera is totally out! So stop hugging the old out-dated pictures.” Mr. Cheung fired back, “Oh, you know nothing. This is something you cannot replace at all, and my camera is a classic.” Smiling at him, Mrs. Cheung took out a new gadget, “Right, right, now calm down. It never hurts to have both worlds. Look what I’ve got you. This is called ‘Stereoscopic Camera Lens’. Its little coloured spectacles can capture everything, say, the sensational Great Pyramid, in three dimensions!” As we are asking for and relying more on technological advances, the Stereoscopic Camera lens and the Stereoscopic Magic Box are surely innovations that promise to add a new dimension to our lives. Surprisingly, the working of these two gadgets involve only some simple scientific theories such as polarization, doping and anaglyph; and employs the special property of Liquid Crystal Layer (LCD) under electric current. Stereoscopic photos can now be easily available to us. Both of our designs, the Stereoscopic Camera Lens and the Stereoscopic Magic Box, can turn something ordinary into extraordinary by making plain, 2-dimensional things ‘stand out’ before your eyes. The Lens itself is crafted with such precision that it can capture any image both faithfully and flawlessly. The Magic Box uses electric current to catalyze and enhance the 3-dimensional transformation. So each picture is vibrant and true-to-life. The Lens and the Magic Box will certainly revolutionize our vision of things around us. To enable you to have a good understanding of the theories behind the making of the Stereoscopic Camera Lens and the Stereoscopic Magic Box, we have made simple models of them with prisms, and they are in display at our booth. Anyone who is interested in these fancy gadgets should definitely come to our booth to experience a new view of the world!

溶液和溶劑置於同一容器中，當溶質向上擴散時，會形成濃度梯度及\r 折射率梯度dn/dy，且dn/dy 對高度y 的關係圖會呈現隨著高度改變的現\r 象。\r 半徑r 的Ｄ形容器，下方置溶液，上方置溶劑，以雷射光照射容器的\r 平面部份時，雷射光沿著法線出射，受折射率梯度的作用而向下偏Ζ距\r 離，a 為容器至屏的距離，得到dn/dy=Z/ar 的關係式；改變雷射光的高\r 度y 可得dn/dy 圖。\r 以硫代硫酸那作實驗，其dn/dy-y 圖為以原始界面為對稱軸，因其擴\r 散係數不隨濃度改變；甘游水溶液的dn/dy-y 圖呈現不對稱，圖形的極\r 大值往甘油方偏，主要係因為甘油的擴散係數隨濃度的增大而減少。\r 我們成功第把不同時間對同一溶液的實驗結果予以模型化，得到的\r dn/dy-y 曲線隨時間改變，並發現該曲線所涵蓋的面積為定值。\r \r The mixing in a vertical column between a pure liquid and a solution produced a concentration gradient, which in turn produced the refractive index gradient. As the solute particles diffused upward into the pure liquid, the gradient was generated by the varying solute concentration. The plot of the refractive index gradient versus vertical position y (dn/dy vs y) is found to be varied with time. A D-shape container of radius r is partly filled with denser solution, and partly filled with solvent which is on the top of solution. When laser beam enters perpendicularly to the flat surface of the container, the outgoing beam strikes the container at normal incidence, and deflected down a vertical distance Z by the refractive index gradient. We can get dn/dy=Z/ar, where a is the distance between the container and the screen,. By changing the vertical position (y) of laser beam, we can get the plot of dn/dy vs y. For a sodium thiosulfate-water solution, the trace of dn/dy vs y is symmetric with respect to the position of original boundary. Since the diffusion coefficient of sodium thiosulfate is independent of concentration. For the trace of dn/dy vs y of a glycerol-water solution, it will no longer be symmetric. A skewed curve which reaches its maximum position is displaced to the glycerol side, because the diffusion coefficient of glycerol is decreased with concentration. We have successfully modeled the time-dependent experimental gradient curves on the same solution. The trace of dn/dy vs. y at different time is found to keep the area constant.

地震波會以橫波和縱波的方式傳遞能量，學校的教學大樓中地下具有蓄水池者搖晃的持續性感覺比較短暫，於是利用彈簧波模擬地震波測試不同質量的台車接收到的能量會較空車為多。並利用自製模型測試不同容器形狀和水量的阻尼作用，結果發現搖擺時，時間球形＞錐形台≒方形台；球形台裝有不同水量時擺動時間裝滿裝滿時＞未裝水＞裝1500mL 時；平行移動時則是球形台裝水2000mL 後鉛錘移動距離最短。整個實驗過程中由於未裝滿水的模型內部重心改變不規律，而且模型內所裝的水量因為不規則擾動經吸收的能量轉換成水溫上升的熱能，因此導致擺動能量的消耗造成擺動時間縮短，如果新式大樓興建時考慮消防蓄水池和水塔的造型和裝水容量，應可以減少地震時的搖晃時間，降低心理的緊張和物體因震動而產生的移動傷害。Seismic wave can transmit energy with transverse and longitudinal wave. The shaking of these buildings with reservoirs underground in our school for a shorter time, so we use spring wave to simulate seismic wave, and test the proportion of transmissible energy received from different mass of objects. The energy gets from wave motion passing on is bigger when cars carrying capacity than empty cars. And we use homemade models to test damped effect of different forms and water. At last we discover the time is Sphere ＞ Taper ≒ Square while they swing with different amounts of water, the time it cost is Full ＞ Non ＞ 1500 mL. When they move horizontally, the plummet moved shortest, when the water of the sphere is 2000 mL. During the whole experiment, the center of gravity in the models, which are not full of water changes irregularly, and the water in the models can absorb heat energy from energy disturbing, so the swing of energy consuming makes the time of the swing shorter. If the fire controls reservoirs, the shapes and dress up water volume of the water towers, are taken into consideration, the duration of the shaking of earthquake will be shortened so that our fear and nervousness will be lessened, and the damage causer from the shaking will be reduced.

Table tennis the fastest ball sport in the world has become so fast that rallies have become\r very short. My investigation this year is a further study into slowing the game down. Last\r year I studied the effects the newly introduced 2mm larger ball had on the game. I\r concluded an average increase in rally length from 2.93 to 3.47 balls per rally passing the\r net. Although a 16% increase sounds large, it was an average of less than 1 ball per rally\r difference. I came up with another way to slow the game down my aim was to find out if\r increasing a table tennis net height will decrease spin, speed and increase control i.e. rally\r length and to find out what percentage extent each height level has on these factors. I\r wanted to be able to present a finding as to the optimum net height for the percentage\r increase in rally length that is desired.

本文所探討的議題為電解質溶滿通以電流後所產生的效應與機制。本實驗所採用的方法為電解與電鍍，運用這兩種方法，來比較電解液在不同狀況下所產生的結果；經過多次的實驗，累積了許多實驗結果，使我們可以得到更精確的數據 · 在此次實驗中，我們發現電解液在相同的電壓下，通以電流後的穩定性與金屬的活性有關，活性越大越不穩定；反之，活性越小越穩定。另一個發現為，只有單一極性離子移動的情形，可通過的電流，比陰陽離 r 同時移動時為大；但因通過的電流大使電解液反應劇烈，產物時時覆蓋電極使電流下降。所以就穩定性來說，是以陰陽離子同時移動為佳 · 在展望方面，希望可以發展到液態磁屏避的設備，可減少設備過重之問題 ·This is a study of how electric current effects the electrolyte solution. The experiment was conducted through two methods: electrolysis and electroplating, the results of which were compared. The experiment of the same designs hi been conducted repeatedly and, as a result, accurate data were collected and accumulated.One of the two major findings from the experiments was that, when under the same voltage, stability of the electric current varied with the change of activity of the metals; the greater the activity of the metals, the less stability of the current, and vice versa. The other major finding was that, with the movement of dipole-ion, a greater amount of current would go through the solution than that which would go through with the movement of cathode and anode; however, the greater amount of current would cause intense reaction of electrolyte solution, hence merging the electrode and reducing the current. So as long as stability is concerned, the movement of cathode and anode is preferable.It is hoped that more sophisticated experiments designed on the basis of the similar principles will eventually lead to the construction of equipment of liquid-magnetic shielding of smaller weight and size.

在高中光學裡，介紹了許多有關光波之特性，而聲波與光波皆具有波動性，因此聲波應具有如干涉、反射、聚焦等特性，但在物理課本上並未詳加敘述，所以我們開始了本項的研究，希望可以籍由改變聲源及邊界的各項條件，而探討其發生之現象。在本研究中，我們利用聲波之基本原理在電腦上進行聲場的模擬並加以改變其變因（頻率、相位、聲源數、聲源間距、強度、邊界反射），進而明瞭聲場之各項特性及應用與控制方式。經電腦模擬聲場圖中，我們觀察到，兩聲源干涉所形成之圖形為多組雙曲線所組成，近似於光學之雙狹縫干涉，增加聲音頻率與聲源間距離皆可使腹(節)線數目增加。如同現實世界中所知的，隨著頻率的增加，將會具有指向性的產生並且在聲源數目越多時越明顯，但發現頻率增加至一定值之後，指向性反而會降低而形成冠狀面。在延遲了多點聲源間相位之後，聲場分佈有偏轉之現象，利用相位延遲的方法，在多聲源中，將兩旁之聲音偏向中央將可造成聲音的聚焦。在兩聲源干涉中，調整其中一聲源之強度，將可完全消除兩音源連線間一點之聲音，可適當的應用在工業上消除噪音。聲場分佈在具有邊界的環境下，我們試著找出聲源位置及邊界條件對聲場分佈的影響與關係以模擬室內聲場，但在簡化的數學模式下，即無法有我們所希望之最均勻聲場分佈產生。最後我們將實驗中的結果與文獻上的實驗數據加以比較，以探討其誤差。 The optical course in senior high school , which introduced many characteristics of optical wave. However, both of sound and light have the characters of wave; therefore, sound wave should have the characteristics, such as interference, reflection and focalizing. Nevertheless, there are not many details of sound wave in the section of acoustic on our textbook. So we began this research, and discuss the different phenomena by changing many kinds of variables. In our research, we simulated the sound field on the computer, based on sound wave’s principle, furthermore we change many variables, which like frequency, phase, source number, distance, intensity and reflection. It helps us understand the characteristics of\r sound, how to control sound and how to apply these findings. According to the result of computer simulation, we discovered that the graph of two acoustic source’s interference comprised by many pairs of hyperbola, just like optical double slit interference. As the frequency or the sound source distance increased, acoustic direction became more and more obvious. But when the frequency was high enough to over the extreme, instead increasing, the acoustic direction would lower down like a crown. After we make phase differences on one of the two sound sources, sound field generated\r deviation. So if we use this method in multiple sound source, and delay the middle source, the sound field might be converged. In such two-sound-source interference pattern, when we control the intensity of one, a certainly point on the line of the two sources disappeared When the sound field enclose by borderline, the standing wave appear, and we discovered many funny phenomena. We put large amount of source in a narrow slit, the phenomenon of diffraction appeared. Finally, we discussed the discrepancies between interference pattern previously done by others experiments and the simulated one conducted by us.

溶液和溶劑置於同一容器中，當溶質向上擴散時，會形成濃度梯度及折射率梯度 dn/dy，且dn/dy 對高度y 的關係圖會呈現隨著高度改變的現象。 半徑r 的Ｄ形容器，下方置溶液，上方置溶劑，以雷射光照射容器的平面部份時， 雷射光沿著法線出射，受折射率梯度的作用而向下偏Ζ距離，a 為容器至屏的距離， 得到dn/dy=Z/ar 的關係式；改變雷射光的高度y 可得dn/dy 圖。 以硫代硫酸那作實驗，其dn/dy-y 圖為以原始界面為對稱軸，因其擴散係數不隨濃 度改變；甘游水溶液的dn/dy-y 圖呈現不對稱，圖形的極大值往甘油方偏，主要係因 為甘油的擴散係數隨濃度的增大而減少。 我們成功第把不同時間對同一溶液的實驗結果予以模型化，得到的dn/dy-y 曲線隨 時間改變，並發現該曲線所涵蓋的面積為定值。 雷射光經光柵再照射半圓筒，可直接測出各高度的折射率，量出y、 dn/dy、n、及濃度可算出擴散係數。The mixing between a pure liquid and a solutionin a vertical column produced a concentration gradient , which in turn produced the refractive index gradient . As the solute particles diffused upward into the pure liquid , a gradient was generated because of the varying solute concentration . The plot of the refractive index gradient versus vertical position y (dn/dy vs y) is found to vary with time . A D-shape container of radius r is partly filled with a dense solution , and partly filled with solvent which is on the top of the solution. When laser beam pendicularly enters the flat surface of the container, the outgoing beam strikes the container at a normal incidence , and is deflected down a vertical distance Z by the refractive index gradient . We can get dn/dy=Z/ar , where a is the distance between the container and the screen . By changing the vertical position (y)of laser beam , we can get the plot of dn/dy vs y . We have successfully modeled the time dependent experimental gradient curves on the same solution . The area beneath the trace of dn/dy vs y at different time is found to be constant . Additionally, with a grating at the center of the semicircle, we can measure the index of refraction n and get the plot of n vs y. The diffusion coefficient D of the solute can be calculated using the plot of dn/dy,y,and time t.

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.