全國中小學科展

2021年

An Easy Method to Discuss Properties of Simplified Solid-state Tesla Coil

Wireless transmission products are widely used in our daily life. In this research, we focus on knowing how solid-state tesla coil works in different conditions and finding the best parameters through an easy way. In our work, a commercial electroscope was used as detector for measuring the strength of radio wave created by our simplified tesla coils. In fact, many factors would lead to experimental erorrs such as detectors, selected types of NPN BJT components, applied voltage and measuring position of height. Therefore, all of the factors were under control to make sure of accuracy and precision for our designed measuring method. In our experiment, graphics of radio wave distribution around tesla coils were drew by mathemetic software of GeoGebra. It shows the BJT types of 2n2222 had good performance for wireless transmisstion efficiency. To our surprised, we found the extended wires (called antenna) from the top of tesla coil also had an ability to transfer electromagnetic energy, and had good retention if the extended wires were within the length of main coil’s height. Finally, the shape’s and size’s effect was determined by our testing work. The result shows that pipe’s length, pipe’s diameter and turns ratio of two coils had great influence on tesla coil’s transmission efficiency. It was found that the tesla’s performance would be more efficient if wire was used to make the length twice rather than make the diameter twice. However, the turns ratio of secondary coil to primary coil would change while making the length twice. To avoid that, we fixed the length and decrease the turns of primary coil. At last, we found tesla coil must work at the turns of primary coil higher than two. Furthermore, the frequency of radio wave not only had less relationship with their length or diameter but also had less relationship with types of BJT In our study, our handmade tesla coil was succesfully applied for wireless charging and we find that the induced voltage decrease in propotion to cube root of distance between tesla coil and induced coil.

重金對抗-重金屬對水蘊草抗氧化活性之研究

本研究採用水蘊草做為水生植物材料,以0.1%、0.5%的鎂離子、鈣離子與銅離子為培養液,於一般光照、全光照與全黑暗的環境下,分析溶氧量、葉綠素a、總抗氧化活性與CAT活性的分析。 所得結果發現低濃度、高濃度的鎂離子、鈣離子在光照的環境下都可以提高溶氧量、提高葉綠素a含量、提高總體抗氧化活性與CAT活性;而銅離子對於水蘊草而言可能是種傷害,都會降低溶氧量、降低葉綠素a含量、降低總體抗氧化活性與CAT活性。

高鐵行經嘉南地區之高鐵低頻震動波

當高鐵行經地層下陷明顯區域、或土壤液化中高潛勢的沖積層時,行車的車身震動會更劇烈嗎?本研究基於這樣的動機,經由測量高鐵沿線不同區段的震動訊號,了解各段的震動特徵。 本次研究使用微機電加速計(MEMS sensor)來量測高鐵行經左營至台北路線上車廂內之震動,並利用QCN Live軟體分析波形,分析行經各站間之頻率與振幅特徵,結果發現,行經台南到嘉義、嘉義至雲林、雲林至彰化三段路線的震動,在濾波0.5-4.0 Hz之平均振幅大於其他非地層下陷與土壤液化地段,同時我們也發現低頻振動的最大振幅在列車行經土壤液化區時有顯著的增加。

Maximum Isosceles Sets

An isosceles set is a collection of points in which any subset of three points forms an isosceles triangle. We want to find the upper bound for the size of isosceles sets in any n-dimensional Euclidean space. Kido has already completed the study of isosceles sets in 3 and 4-dimensional space. We study the upper bound of spherical two-distance sets, a special type of isosceles sets, to help us find the upper bound of isosceles sets. More specifically, Musin’s Linear Programming technique on spherical two-distance sets could be used to study isosceles sets if a consistent relationship between isosceles sets and two-distance sets can be characterized. We offer a conjecture of this relationship. We also offer non-trivial lower bounds of isosceles sets in dimension 5 with 17 points and dimension 7 with 30 points as examples.

水流曲面與初始物理量值關係之研究

在理想狀態下,由一個圓形且開口面平行於地面的水龍頭開口中流出的水柱會呈現一以 z 軸對稱、切面積往 z 軸負向遞減的圓形疊合曲面。此曲面形狀受到下列三種物理量值影響: 一、水流在水龍頭開口瞬間速度(在此稱之為初速度) v0 二、水龍頭圓形開口半徑(在此稱為初半徑) r0 三、重力加速度 g 為了更清楚瞭解此曲面性質及在不同狀況下(三種物理量值改變情況下對曲面的影響),故提出下列問題在研究中探討: 一、這三種物理量值,對曲面形狀的影響為何? 二、這三種物理量值,對曲面曲率影響為何?

Solar Powering Day and Night with Boxed Micro-Biosphere

本研究在生物光伏電池(Bio-photovoltaics, BPV)的陽極添加能氧化含氮廢物放出電子的硝化菌,並在陰極添加能吸收電子還原硝酸鹽與硫酸鹽產生氮氣與硫化氫的厭氧菌,建立不需外部供給物質,能夠自我維持且不斷發電的微型生態圈(Boxed Micro-Biosphere, BMB)。實驗結果顯示在陽極加入硝化菌後,能使含小球藻與共生菌Sym1的BMB功率提升38倍至99.46±9.31μW · m-2,而在陰極加入厭氧菌能讓功率再提升至262.51±37.30 μW · m-2,且此電池截至目前為止已運轉超過4272小時,發電功率仍保有67.4%(176.98 μW · m-2)。若將Sym1與Sym2同時加入陽極則可使功率密度提高至463.19±25.50 (μW · m-2),夜間功率可達白天的93.1%,但在野外實驗環境下一週內就失去發電能力。若將BMB中小球藻換成來自高溫與強酸環境的溫泉藻(H),其野外平均功率為388.80±14.87 μW · m-2,夜間發電量為白天97.9%,其功率與壽命(目前尚在運作中)遠高於小球藻BMB。 未來我們將篩選能加強溫泉藻發電能力的共生菌使其更具實用性。

利用海冰體積與北極震盪指數預測聖嬰現象發生之可能性

本研究利用海冰覆蓋面積的變化、北極震盪指數(Arctic Oscillation index, AOI)和南方震盪指數(Southern Oscillation index, SOI)的相關性,希望可以探討與聖嬰現象的關聯。 取用1950年到2020年的海冰覆蓋面積資料及195!年到2020年的SOI及AOI資料。我們將AOI和SOI做折線圖、X-Y圖,數據分成平常年、聖嬰前、聖嬰時、聖嬰後、反聖嬰前、反聖嬰時、反聖嬰後,試圖找出一些規則。利用區間分析來觀察區間範圍大小及上下界的數值隨不同事件發生的次序,探討各個事件的特徵。 聖嬰年時,區間縮小,反聖嬰年則區間略為放大且數值上升。最後將1997年聖嬰年的數據和區間做疊圖,並以2018年底到2020年的聖嬰轉反聖嬰來做驗證。若AOI的區間縮小、或海冰覆蓋面積下降後上升,表示可能是聖嬰現象要來的前兆。此外,本研究也發現,無法單獨區隔聖嬰年和反聖嬰年,兩者間會相互影響,應該要把聖嬰跟反聖嬰合併為一個氣候變化週期,才能做準確的預測。

探討果蠅腦部神經突導向的基因調控

本研究利用RNA干擾與基因過度表現兩種方法,觀察基因表現對果蠅蕈狀體神經突導向的影響。我們以RNA干擾方式降低基因表現,標定dally、octβ2r、sifr與frazzled基因;而基因過度表現則選定frazzled基因。利用果蠅GAL4-UAS系統使神經細胞表現的綠色螢光蛋白,觀察神經突導向情形。由干擾果蠅腦部蕈狀體PPL1-α′2α2神經細胞上述基因,觀察到dally、octβ2r基因在降低表現後,此細胞分別呈現失去神經支配與異常神經支配。sifr基因在兩種不同RNA干擾序列下,表現出不同之結果,一是和wild type的神經突型態相似、另一則是失去神經支配。frazzled基因干擾後,細胞在蕈狀體α2區失去神經支配。frazzled基因在過度表現下,神經突和wild type相比,出現異常導向。綜言之,由我們研究發現透過操控基因表現,果蠅腦部神經突會產生異常的導向與神經支配,顯示果蠅腦部神經系統在分化或發育上,基因扮演極為重要的角色。

利用SLC13A3基因於果蠅體內建構代謝疾病模型

隨著慢性代謝疾病日益普及,藥物的研發及測藥用的生物模型也越來越被重視,因此我們欲建立一個模擬代謝疾病的生物模型,以供藥物測試對象。有研究發現,當果蠅身上發生I'm not dead yet (Indy)基因突變時,會使果蠅在高熱量飲食狀態下延長壽命、降低體重增長,且影響果蠅體內脂質的代謝功能,目前認為這些現象與養分運輸進入細胞的減少有相關。本實驗中我們將存在於人類身上且為Indy基因的哺乳類同源基因Solute carrier family 13, member 3 (SLC13A3)轉殖入果蠅體內,並分別在全身、頭部脂肪體、腹部脂肪體及神經細胞中過度表達後,觀察果蠅的生長與代謝變化。實驗結果發現SLC13A3基因於果蠅的頭部脂肪體及神經細胞表達確實會出現與代謝疾病患者類似的生理現象,如壽命縮短、體重及三酸甘油脂增加等,且此作用機制與AMPK 訊息傳遞路徑相關。因此我們認為SLC13A3基因於果蠅體內過量表達適合做為代謝疾病的生物模型,對於往後藥物開發極具潛力。

五苯荑衍生物的多重螢光響應行為

本研究探討兩種五苯荑氟鏈取代衍生物(簡稱F5及F9)的刺激響應之特性及應用。F5及F9化合物粉末受到外力研磨以及蒸氣薰致時會產生力致螢光變色(Mechanochromism)及薰致螢光變色(Vapochromism)反應,我們選擇使用F5,利用放光光譜及PXRD對這兩種反應的機制進行探討。 再者,我們利用揮發法把F5及F9粉末製成晶體,以螢光顯微鏡照射340–390nm的紫外光,觀察F5及F9晶體的光致機械螢光變色(Photomechanofluorochromism)及F9晶體的光機械運動(Photomechanical effect),並利用放光光譜對其機制進行研究。 另外,我們將F5粉末長時間照射紫外光製備光二聚體(Photodimer),接著透過加熱使光二聚體熱回復回單體。再利用NMR測得各加熱時間下光二聚體與單體的比例,並由此推算出光二聚體熱回復性的反應速率常數。 此外,我們將F5混摻PEDOT:PSS,用drop-casting製成薄膜,觀察螢光變化,並討論其機制。 最後,我們結合力致螢光變色、薰致螢光變色和光致機械螢光變色,應用於多彩螢光繪圖。