超聲波應用之研究
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.
以簡易方法探討奈米銀的化學活性優於非奈米級銀粒子
A novel and simple method was developed to determine the activity of silver in nanometer particles more than in non-nanometer particles. The conductivity of conducting polymer, polyaniline (PANI) doped with different amount of nanometer silver particles was used to evaluated the activity of nanometer silver. In polymerization of polyaniline, hydrogen chloride solution usually used to increase the conductivity of polyaniline. When 1%(w/w) nanometer silver particles doped during the polymerization, the conductivity of polyaniline was down from 2.28 s/cm to 0.65 s/cm, then increased with increasing the amount of nanometer silver doped. The conductivity of polyaniline was changed from 2.28 s/cm to 0.47 s/cm when 3%(w/w) nanometer silver particles doped, but it is increased from 2.28 s/cm to 2.44 s/cm when was doped with 3%(w/w) micrometer silver particles. The conductivity of polyaniline changed due to the formation of silver chloride (AgCl) in doping nanometer silver. Some of the nanometer silver particles were formed to silver ion in hydrogen chloride solution for the high activity property of nanometer silver. This also can be proved from the spectra of XRD and FE-SEM. Therefore; determination the conductivity of conducting polymer by doping nanometer metal particles can be used to determine the activity of the nanometer particles. 本研究為開發一個新穎的檢測奈米金屬粒子化學活性大於非奈米金屬粒子的簡易方法。方法為利用導電高分子聚苯胺,於合成過程中添加不同濃度的奈米銀粒子,並分別偵測其成品的導電度,藉以評估奈米銀粒子的化學活性。由於聚苯胺在合成過程中通常加入鹽酸以提高其導電度,致活性較大的奈米銀粒子於氧化後,隨即與氯離子形成氯化銀的沉澱,而降低聚苯胺的導電度,如添加1﹪(w/w)奈米銀粒子的,其導電度由2.28 s/cm 降至0.65 s/cm,隨後隨著添加量的增加導電度先降後再稍回升。一般非奈米級銀粒子因氧化電位為負值,即化學活性小,而不易被氧化。由實驗結果,我們發現同樣添加3%(w/w)的奈米級銀粒子或微米級銀粒子,添加奈米級銀粒子的導電度由2.28 下降為0.47,添加微米級銀粒子的導電度卻由2.28 上升為2.44,此乃說明本方法確實足以證明奈米級金屬的化學活性的確遠大於微米級金屬,因相同條件下,微米級銀粒子未如同奈米級銀粒子一樣被氧化成銀離子。即奈米級銀粒子可以輕易的被氧化,而非奈米級銀粒子則不易被氧化。尤其也可由X 光繞射儀分析光譜圖和場發射式掃描電子顯微鏡拍攝圖證明。因此,我們可以採用添加3 %(w/w)奈米級金屬銀粒子及微米級金屬銀粒子於導電高分子的方法,並藉導電度的變化,證明奈米金屬粒子的高活潑性。
討論顯微鏡下的化學反應
由於想了解化學反應的微觀形態,我們設計微型化學反應裝置來比較巨觀(傳統型)與微觀(創新型)化學反應間的差異,並探討其實用及環保方面的問題。在顯微鏡底下,我們觀察化學反應的沉澱結晶及電解反應,嘗試以各項變因(溫度、濃度、聲波…等)來觀察其結晶的型態。我們已成功地將實驗藥品用量減少到一滴(約0.04ml),並以微觀的角度觀察化學反應的過程。在實驗中,發現反應進行時,粒子會不斷流動,經查證後為愛因斯坦所提出的布朗運動,並且測得硫顆粒的直徑大小約4.2 ~ 6.7 微米。不同聲波所造成硫粒子的移動速率不同,而不同溫度的部份,我們發現→每增加十度硫粒子移動速率增加約兩倍。在面積4.392×10-4cm2 範圍內大約有250~300 顆硫沉澱的粒子。本實驗成功地將顯微鏡應用在化學領域上,若將此實驗推廣,可達到污染少、觀察實驗的時間短、用量少的目標。此實驗是邁向化學微觀世界,一種值得嘗試且創新的方法。In order to compare the differences between the chemical reactions of macroscopic reactor and microscopic reactor, we have designed a device of chemical reaction and researched into the problems of their environmental protections and practical aspects. Under the microscope, we observed not only their precipitating crystal compound from the chemical reaction and electrolytic reation but their types of crystal. We have successfully reduced the dose to one drop ( about 0.04ml) and observed the process of their chemical reaction from the angle of microscopic reactor. During performing the experiment, we found the particles would keep flowing while the reaction was working. It was proved as "Brown motion" introduced by Einstein. The diameter of these particles were around 4.2~6.7μm. We find that different sound waves and temperatures,the motion speeds are quite different. And the movement rate increases about two times as the sulfer particles increase 10℃ each time .Within the measure of area of 4.392×10-4cm2,there are 250~300 sulfer particles.The experiment has successfully used a microscope in the field of chemistry. If we popularize the experiment, we can reach the goal of less pollution, fewer the dose and time-saving observation. It’s an innovation to step to the world of chemical microscope world.
輸贏一線間-淘汰賽的相關探討
單淘汰賽是一種失敗一次即遭淘汰的賽制;在此假定每位選手都有一相對應的能力數值,本文主要探討在均高的單淘汰賽程表之下,若賽程安排完全依照種子安排原則(亦即最強的選手對最弱的選手、次強隊次弱….),則對於能力越強的選手越有保障,直觀上而言能力最強的選手應有最大的奪冠機率,探討此種賽程安排是否滿足能力較強的選手有較大的勝率?因發現在某些特殊的選手能力數值分佈之下會發生次強選手勝率大於最強選手的情況,令A、B代表最強與次強選手,P(A)、P(B)代表A、B奪冠的機率,故擬定P(B)/ P(A)為參考依據,尋求P(B)/ P(A)的最大值發生處作為最極端的狀況。發現四位選手的情況下,P(B) / P(A)最大值 = 1;八位選手的情況下,P(B) / P(A)最大值=(196+98) / 343=1.0938,當選手數為2n時,P(B)/ P(A)最大值隨n的增加而遞增。
Knockout Tournament is a highly competitive system in which any player losing a game can no longer play in the tournament. Here we suppose that every player has a numerical value that corresponds to his ability. We consider a totally-seeded knockout tournament with 2n players where in the first round, the strongest player matches the weakest player, the second strongest player matches the second weakest player, and so on. We examine whether a stronger player always has a greater probability of winning the tournament. The answer is in the affirmative for n = 2. For a tournament with eight players(n = 3), the situation is much more complicated. In certain cases, the second strongest player has the greatest probability of winning the tournament. Specifically, let A and B denote the strongest and second strongest players, P(A) and P(B) their respective probability of winning the tournament. We find that the maximum value of P(B)/P(A)equals (196+98) / 343 = 1.0938. For n > 3, we have not obtained the maximum value of P(B) / P(A) . However, it can be readily seen that the maximum value of P(B) / P(A) is non-decreasing as n increases.