調幅超聲波解調高指向可聽音之研究
可聽聲有向四周擴散繞射特性，而超聲波具有指向性，改以超聲波載送可聽音訊號後，其載波與旁頻帶均在超聲波範圍，實驗中人耳卻可聽到高度指向性聲音，且調幅解調後的可聽聲衰減率比純超聲波來的低。那為什麼超聲波會解調可聽音？我們以非線性的數學轉換概念，成功以數學推導解釋實驗中所聽到的可聽聲，是由旁頻經由非線性轉換而來的。為了證實空氣中的超聲波有非線性現象，以發射40KHz單頻訊號，除了接收到40KHz訊號外還可接收80KHz訊號，而80KHz訊號振幅，會隨著發射強度而遞增，也會隨著傳輸距離增加至穩定狀態，這所我們從文獻中的非線性理論所吻合。接下來進行調幅超聲波實驗，我們經理論計算旁頻帶強度為頻率響應與調變率乘積的一半，而解調可聽聲的強度為調變率、頻率響應與非線性係數三者乘積，我們也由實驗數據證實理論計算結果，在實驗中，換能器在40KHz有最佳的頻率響應，其非線性係數與所載送可聽聲頻率高低約略成正相關，並且與換能器距離遞增而越遠而增加。此外在提高高指向可聽音輸出功率方面，除製作專屬的放大器、運用方波取代正弦波來載波、配合陣列換能器輸出；在改善音質方面，利用等化器調整訊源頻譜分佈，降低低頻振幅，增強高頻振幅，讓各頻率的原始訊號都能有適當的調變，達到最佳音質。The audible sound has the characteristics of spreading and diffracting. And ultrasonic is directive. We modulate sound into ultrasonic signal. The carrier and sideband are ultrasonic frequency bands. But in the experiment, human can hear highly directive sound. In terms of attenuation rate, AM demodulation sound is lower than pure ultrasonic wave. Why can human hear the directive sound? By using the nonlinear mathematical transform, we managed to explain the audible sound which is transformed from sideband with nonlinear effect in the experiment. In order to confirm that nonlinear phenomena in the air ultrasonic, we launch 40KHz single tone ultrasonic signal. Besides the 40KHz signal, we also received 80KHz signal. The amplitude of 80KHz signal will increase with the emission intensity, and also with the transmission distance to increase its stability. These are consistent with nonlinear theory in the literature. Next we began AM ultrasonic experiment. We calculated the sideband intensity that is the product of frequency response and modulation index. The demodulation sound intensity is the product of modulation index, frequency response, and nonlinear coefficient. We also proved the calculated consequence through the experiment. In the experiment, the ultrasonic transducer has a best frequency response in 40KHz. The nonlinear coefficient has positive correlation with the modulation frequency, and increases transmission distance. To boost the power of directive audible sound, we made an amplifier, using square wave to replace sine wave of carrier, and in conjunction with array transducer output. To improve the sound quality, We use the spectrum-Equalizer to adjust the frequency distribution of the origin signal. The EQ reduces the low-frequency amplitude, and boost high-frequency amplitude, which enables every frequency of the original signal to be properly modulated, achieving the best sound quality.
自由基VS抗氧化物
自由基會產生在神經系統、免疫系統、血液循環系統等等，進而影響到人體各器官的運作,甚至於近年來許多醫生學者提出自由基病理:自由基是百病之源。本次實驗筆者挑選葡萄子、維生素C、綠茶來抑制清氧自由基(OH.)所採用的方法是將10%雙氧水製入注射筒並加亞鐵離子催化,,使其與抗氧化物反應,由於雙氧水分解會產生氫氣自由基與氧氣,因此筆者用倍率放大器(OPA)放大生成氧氣造成的電壓,並用Data Studio測量記錄,最後可由氧氣體積對電壓的趨勢圖看出抑制氫氣自由基的效果;Free radicals will be produced in our nerves system blood circulation immunization system etc. and they able to influene the operaion for our organs many medical scholars have even come up with "free radical pathology"-free radicals are sourse of all he diseases in recent years.In this study, I chose rape stone vitaminC and green tea to restrain hydroxide radicals(OH.) Here is summary of the experimental process. First,I put 10%hydrogen peroxide into an injector and then added ferrous ion to hydrogen peroxide to catalyze it. Second I let it reaact with the sample. Because hydrogen peroxide can produce hydroxide radicals and oxygen, I used the mutiplier(OPA) to amplify the pressure caused with the prducion of oxygen, measuring and recording resuls by the software"Data Studio"Finally, we can tell which antioxidant is more effective in restraining hydrode radicals from volume-voltage gragh.
三個新的鋅的幾何異構物
在本實驗中，我們合成了三個新的鋅的幾何異構物：trans-facial-[Zn(dipica)₂]Cl2.CH3OH(dipica=dipicolylamine，C12H13N3，雙(2吡啶甲基)胺)trans-facial-[Zn(dien)2]Cl2(dien=diethylenetriamine，C4H14N3，二乙基三胺)及反式-[Zn(demn)2Cl2](demn=N,N’-dimethylethylenediamineC4H12N2，N,N'-二甲基乙二胺)。本實驗的特色皆在室溫下反應，採用擴散法培養晶體。trans-facial-[Zn(dipica)22]Cl2.CH3OH晶體為三斜晶系，晶格常數a=8.8269(6)Å, b=8.9908(6)Å, c=10.0292(6)Å,α=76.715(1)。,β=81.232(1)。,γ=67.753(1)。;其空間群為P1，可信度R=0.025,Rw=0.0697。六配位的陽離子，其結構為扭曲八面體，兩個含氮三牙基(dipica)trans-facial配位，赤道面(ZnN(1)N(2)N(1A)N(2A))由兩個含吡啶環之氮(N(1)、N(1A))及兩個飽和胺之氮(N(2)、N(2A))所組成。主軸為兩個吡啶環之氮所組成。兩個含氮三牙基(dipica)與鋅的咬合角皆為84.5。。trans-facial-[Zn(dien)2]Cl2晶體為單斜晶系，晶格常數為a=11.3050(3)Å,b=10.9264(3)Å, c=12.6147(3)Å,β=92.884(1)。;其空間群為P21/c，可信度R=0.0191，Rw=0.0484。六配位的離子，其結構為扭曲八面體，兩個含氮三牙基(dien)與鋅的咬合角為156°、157°。反式-[Zn(dmen)2Cl2]晶體為單斜晶系，晶格常數 a=10.3397(4)Å,b=8.5916(4)Å,c=7.9774(3)Å,β=100.520(1)°;其空間群為C2/m，可信度R=0.0266，Rw=0.0686。其結構為八面體，鋅原子四個氮原子組成赤道面(ZnN(1)N(1A)N(1B)N(1C))，兩個氯原子位於此平面的兩側。兩個含氮雙牙基(dmen)與鋅的咬合角皆為83.0(1)Å。
In this study, we have synthesized three new geometrical isomers of zinc(II)complexes: trans-facial-bis(dipicolylamine)zinc(II)chloride-mathanol(1/2)(trans-fac-[Zn(dipica)2]Cl2.2CH3OH), trans-facial-bis(ethylenetriamine)zinc(II)chloride(trans-fac[Zn(dien)2]Cl2)and trans-bis(N, N'-dimethylethylenetriamine)zinc(II)chloride(trans-[Zn(dmen)2]Cl2). The crystals suitable for X-ray diffraction were obtained by slow diffusion of ether to solution of the products. There molecular strctures determined by X-ray diffraction. The complex trans-fac-[Zn(dipica)2]Cl2.2CH3OH crystallizes in the triclinic space group P 1 with a=8.8269(6)Å, b=8.9908(6)Å, c=10.0292(6)Å,α=76.715(1)。,β=81.232(1)。,γ= 67.753(1)。, for Z=1. The R value is 0.0259 for 3286 significant reflections. In the hexacoordinate cation, the two tridentate dipicolylamine ligands are trans-facially coordinated with two pyridine nitrogens and two secondary amine nitrogens situated on four positions in a basal plane(ZnN(1)N(2)N(1A)N(2A)). The remaining two pyridine nitrogens constitute the axis in a distorted octahedra structure. Colorless trans-fac-[Zn(dien)2]Cl2 crystallizes the monoclinic space group P21/c with a=11.3050(3)Å, b=10.9264(3)Å, c =12.6147(3)Å,β=92.884(1)。,and Z=1. The R value is 0.0191 for 3285 significant reflections. The zinc(II) atom has distorted octahedra coordination, in which the ligands are bound in a trans-facial configuration. Colorless trans-[Zn(dmen)2Cl2] crystallizes the monoclinic space group C2/m with a=10.3397(4)Å, b= 8.5916(4)Å, c=7.9774(3)Å,β=100.520(1)。, and Z=2. The R value is 0.0266 for 856 significant reflections. The zinc(II)atom of trans-[Zn(dmen)2Cl2]is six coordinate with 4 nitrogens of bidentate dmen forming a basal plane(ZnN(1)N(1B)N(1A)N(1C)),and two chlorines on the axial sites completing an octahedra structure.
磁粉探傷原理探討－鐵粉在靜磁場中的受力與運動情形
磁粉探傷過程包含兩個重要的物理現象，其一是磁力線於工作瑕疵處的漏磁現象而形成邊緣磁場，其二是鐵粉顆粒受邊緣磁場的影響而向工作瑕疵處附近聚集現象分別反應出磁場在通過不同介質時所遵循的折射原哩，以及磁場分佈對鐵粉顆粒產生的磁力原理。本研究以電磁通電產生靜磁場，並利用兩電磁鐵間的氣隙來模擬工件瑕疵，因電磁鐵的磁導係數遠大於空氣之磁導係數而造成漏磁場方向機與漏磁面垂直，形成一單純的邊界條件使得邊緣磁通密度的解析解可直接利用馬克斯威爾方程式求得。我們亦導出空氣中的磁通分佈對微小的鐵粉顆粒所產生的磁力公式，發現鐵粉顆粒受靜磁力的大小與該顆粒的體積、磁通密度與磁通密度之梯度成正比，而其方向則與磁通密度之梯度一致，此結論與磁粉探傷過程中，鐵粉向工件瑕疵處聚集的現象吻合。實驗設計採用螢光粉混合鐵粉以獲致明顯的鐵粉顆粒運動軌跡，用數位錄影機紀錄後再擷取影像圖檔判讀其位置與時間之關係，進而反算鐵粉顆粒之位置與所受之靜磁力的關係，以定量的方式證實所推導的邊緣磁場分佈公式以及磁力公式。Two important physical phenomena are observed in the practice of magnetic particle inspection (MPI). The first one is that leakage flux is present in the defect area of the work-piece under inspection. The second one is that magnetic particles aggregate in the vicinity of the defect. These phenomena manifest the theory of flux refraction, which occurs in the intersection area of two different magnetic materials, and the theory of magneto-static force, which is experienced by the iron powder in a magnetic field distribution. Two electromagnets, made of cast steel, are aligned together such that the leakage flux in the air gap forms a fringing field distribution. It is this magnetic field distribution that simulates a defect area in a magnetized magnetic work-piece. Since the permeability of cast steel is far larger than that of air, the direction of the fringing field at the surface of the electromagnets is almost perpendicular to the surface. Such a simple geometry renders an analytical solution to the Maxwell’s equations. The magnetic force of the magneto-static field exerting on the magnetic particle, an iron powder in this case, can be derived by using the principle of virtual displacement. We obtain a formula of magnetic force, whose direction coincides with the gradient of the magnetic flux density and whose magnitude is proportional to the magnitude of the particle volume, the magnetic flux density and its gradient. This formula also agrees with the observation in MPI that the magnetic particles aggregate in the vicinity of the defect.
奈米溶膠製成蓮花效應及應用
Lotus effect（蓮花效應）是蓮葉表面化學組成（wax）與物理組成（微纖維結構）兩者所造成。本研究是以模擬Lotus effect，採用Sol-Gel 製成，將氟化矽聚合為奈米膠體。實驗結果發現，以異丙醇為溶劑，再依序加入氟化矽、硝酸以製成的Sol-Gel，將其塗覆於玻璃表面，可得到最高的接觸角（114.71°），且少量的氟化矽可製成大量的成品，已具有實用價值又兼顧成本的優點，最重要的是，本研究克服了目前Sol-Gel 製程與應用的四大難題（機械強度、與基材接著問題、透明度、溶膠凝固問題），可說是一大創舉。利用所研發出來的奈米溶膠，我們能成功地將Sol-Gel 附著於布料、玻璃、釉表面、粉體，也能成功地研發出具有自潔透氣的布料、救生衣、雪衣、棉被及自潔功能的玻璃、磁磚與市面上尚未研發出的防水粉體（接觸角＞140°），因此我們研發出的Sol-Gel 應用甚廣，有無限的發展潛力。Chemical composition (wax) and physical characteristics (microstructure) of lotus leaves are both responsible of the so call Lotus Effect. In this study we intend to demonstrate louts effect by applying Sol-Gel method to polymerize fluorosilane into nano-scale colloid. Our experimental results shown that the sol-gel made based on isopropanol solvent with fluorosilane and nitric acid added in order, when coated on glass plate, can achieve highest (liquid-surface) contact angle of 114.7 degrees. In addition, only small quantity of fluorosilane is sufficient to produce large amount of product, making this method feasible and cost-effective. More importantly, this procedure overcome the four major difficulty of sol-gel processing and application, namely mechanical toughness, adhesion with substrate, transparency, and consolidation. Using the nano-sol-gel developed in this study, we have successfully coated the sol-gel onto fabric, glass, ceramic grazing surface, and powder, which allow one to make self-cleaning breathable clothes, life jacket, snow cloth, futon and self-cleaning glass and tiles, as well as water-proof powder (contact angle > 140 degrees) which is brand new on market. We therefore believe that there is a great potential for the application of sol-gel developed in this study.