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大地的海棉寶寶--腐植土與山坡地的吸收能力之關係探討
長久以來,颱風總是令台灣的民眾苦惱不已。過去我們都認為開墾山坡地,造成沒有樹根能抓土壤,以致於土石流的發生。但經實地觀察後發現,許多土石流發生地,上方的樹木依然存在!所以我覺得除了樹根之外,或許土壤本身也是個重大的因素。經實驗後發現,土表上的腐植土擁有較一般土壤高的吸水量和滲透能力;再進一步實驗,發現腐植土在過乾的情形下,有吸收不佳的情況。這代表種植作物前的整地行為,似乎也是土石流的一大原因。即使有樹木,但整地的行為,使經年累月所囤積的腐植土被剷除殆盡,導致沒有東西能保護土壤的情況。所以,適度留下樹木、少些開發、避免多次反覆種植,才是遠離土石流、維護台灣水土保持的不二法門。
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『液』想不到的對流胞-瑞利貝納爾對流胞之探討
我們發現味噌湯靜置時會呈現特殊的圖形,經研究發現可能與熱對流有關,便針對與其形成之圖案展開研究。我們的研究主要在探討各種環境上的變因(例如:流體的「濃度」、「厚度」與「溫度」)對對流胞的形狀、大小與溫度分布的影響。此外,我們也針對「不同溫度之液體混合」,以及「外加不同溫度之固體」對對流胞形成的影響。之後,我們改變液體的「黏滯性」,將實驗流體換成的組合,分析討論其對流胞與矽油所產生的對流胞之間的差異。希望能對「對流胞」的形成有進一步的認識,以便將來從事相關研究(如大氣、地球地函的活動等)時能有更深入的了解。
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在高二學數學的時候,老師曾提到共軸圓系有所謂極限點的名稱 ,但當時對於極限點的求法並未詳細介紹,我們為了進一步了解,便在蔡安華、郭茂雄兩位老師的指導下,根據共軸圓系極限點的定義,導出一般共軸圓系極限點的求法公式,同時也探討有關極限點的一些性質,更將這種方法推廣以達三度空間共根面球系時,發現也有相同關係,雖然這項結果也許不是新的,但是在探討的過程中,卻也提供了我們學習方法的一項模式。
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蚵(即牡蠣)在各類海鮮食物中,因為味道鮮美,營養豐富,被稱為「海中之牛乳」,已逐漸為大家所喜好,可惜近年來,產量大減,不僅嚴重的影響到蚵民的生計,而且因為市價奇昂,消費奢的負担增加,使原來物美價廉的海產食物成為家庭主婦們裹足不前的對象。
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近日颱風頻繁,家家戶戶常停電,手電筒成了必須之品。有時找到了手電筒,卻忘了放電池,又要摸半天,加上電池放久了,又容易沒電,且電池的電能終將會用完,那時又該怎麼辦?有鑒於諸如此類的狀況,我們利用國中理化第三冊十二章與十四章裡,所學到的磁場改變可以使得線圈產生感應電流,在此我們利用整流器把感應出電流變為直流電,又由於磁鐵及線圈的運動速率不同,使得所產生感應電流值不均勻,磁鐵運動至線圈每一個地方感應出來的電流值不一樣,所以我們利用加上電容器將電能儲存再慢慢放電;在此電容有充電作用及兼具有濾波作用。再者我們使用發光二極體當成電光源,因此加上 1.5k 歐姆,1/2W 電阻及齊納二極體是穩壓作用,使負載工作電壓穩定,不使負載燒壞。另加上 2.2K 歐姆 1/2W 電阻是限流作用,保護發光二極體。於是我們做出了非常實用的不用電的手電筒,甚至做出了有趣的洋娃娃玩具,成功的收集並利用電磁感應所產生的電流成為一種不耗費資源的環保能源。
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印度莕菜由沉水型轉為浮水型的支撐機制探討
The special life cycle of the Nymphoides indica: The veins and petioles of the pleustonic leaves can asexually reproduce adventitious buds. Pleustonic adventitious buds will change the density of the plants and sink into water. When the root of submersible plants attaches to the bottom of the pool, they will extend stems to the water surface and resume the life cycle. Reticulate sigmons and astral sclerenchyma appears in the process of transformation. Astral sclerenchyma merely appear in the species of which its leaves float above the water surface, and Nymphoides sp. are the most obvious. The cell wall thickness of astral sclerenchyma is even. The cells are hollow and full of water, and they will utilize water to change turgor between axes and spines. This is also proved in imitating experiments. The reticulate sigmons are frequently seen among aguatic plants, and the horizontal structures prevent air space from collapsing. These two structures make the thin stems of Nymphoides indica sustain the leaves instead of being crushed by the floating water. 印度莕菜 ( Nymphoides indica )獨特的生長週期:浮水型葉的葉脈和葉柄可以無性繁殖不定芽,浮水型的不定芽會改變植株的密度而沉入水中,當沉水型植株的根系在池底固著後,便會以莖延伸出水面,再次展開浮水型葉的成長週期。轉變過程中會出現網狀的橫膈和星狀厚壁細胞。星狀厚壁細胞僅出現於葉片需由水中浮出水面生長的植物種類,而莕菜屬植物更明顯。星狀厚壁細胞其細胞壁厚度均勻,細胞中空且充滿水分,會利用水分在中軸與突起的棘間移動來改變膨壓變化,在模擬的實驗中也得到證實。網狀的橫膈在水生植物中是較常見到的構造,水平方向的支撐可以讓氣室不會塌陷,兩種構造的作用下使得印度莕菜細長的莖能夠支撐葉片,不會被流水沖斷。
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本研究探討正方形、正三角形、正六邊形正則鑲嵌格子,無論其是否被塗色,與其相鄰的鑲嵌格子最多僅允許一至數格被塗色的條件,其存在最多塗色格子的數量及存在塗色方式的問題。本研究利用塗色格子位於邊線角落、非角落的邊線、或鑲嵌內部的共用邊數差異、及與塗色格子總數間的限制條件,採用賦值法解析最大塗色格數的上界。接著,利用塗色建構符合解析上界的塗色方式,以數學歸納法推導最大塗色格數的通式,並求證其與解析上界的塗色數量相同,證得確實存在該最多塗色格子數量。研究推廣至n→∞時,各正則鑲嵌塗色面積比率的極限值均收斂至特定數值,且發現當外框邊線效應消失時,以特定週期(鑲嵌層數)累計最大塗色格子數均可表示成數列g(l)=f((l)-f(l-1), h(l+1)=g(l+1)-g(l)≡C2, l∈N, f(0)=C1的形式。
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流行病的傳染過程如同一個無尺度網路,但較一般無尺度網路有著更多的變數而明顯差異,因此無法直接應用一般的無尺度網路模式來描述其傳染途徑。我建立一個新模式「無尺度流行病模式」,經由比較模擬結果與疾病管制局的數據,證實此「無尺度流行病模式」是正確與確切可用,且適用於短期暴發性傳染病與長期流行病。SARS案例研究結果,顯示影響SARS疾病傳染因子的大小是:ψ>m>γ。其中降低ψ值可使SARS確定病例至5月31日止降為143人(減少確定病例190人,相當於減少死亡21人);僅提高防疫使5=γ,亦可使確定病例減至307人(減少確定病例26人,相當於減少死亡3人)。因此強化隔離措施以減少傳染天數最為重要,且可以有效控制每日SARS新增病例,避免發生高侵襲率的現象。HIV/AIDS案例研究結果,獲知採用ψ值來進行月份模擬,則至 2005年12月HIV(+)與AIDS分別為可減少2,715與285人。而進行年度模擬結果,則至 2014年底HIV(+)與AIDS分別為可減少41,936與5,328人。無尺度流行病模式可以協助所需警戒的程度與政策決定的計畫結果。因此無尺度流行病模式在幫助政府評估社會經濟成本與健康憂慮上的有用之工具。當面臨一個全然無知的新病毒的侵襲時,如何減少死亡與傷害人數?是本研究之最終目的。因此,本研究結合了流行病、無尺度網路與灰預測,建立面對病毒侵襲,一個確切可行的對抗無尺度流行病傳染新方法,並詳細說明運作流程。\r \r \r The course of epidemic infections resembles a scale-free network. However, they are different due to more variables in the epidemic infection. Therefore, the model of scale-free networks is not enough to satisfy the reality epidemic infections. In this study, I propose a new the Scale-Free Epidemic Model. Comparison of the simulation results with Taiwan CDC report data for SARS and HIV/AIDS cases show that the Scale-Free Epidemic Model is accurate and useful. This model can be used in the short-term outbreak of infectious diseases and for the longer-term epidemics. In the SARS case study, the results show that the sequence of effect of the epidemic factors was: ψ>m>γ. The SARS confirmed cases would decrease to 143 cases (reduced 190 confirmed cases or 3 death cases) calculated to May 31, 2003, if the average infection time was reduced to two days (an optimum value of ψ). Therefore, vigorous action in isolation quarantine and treatment for SARS cases is most effective policy; the number of new cases and the attack rate would also decrease. In the HIV/AIDS case study, the simulation results of the Scale-Free Model indicates that the reduced numbers of HIV(+) and AIDS in the monthly simulation calculated to December 2005 are 2,310 and 361 and the annual simulation by December 2014 are 27,161 and 3,710. The Scale-Free Epidemic model can help determine the level of caution needed and the projected results of policy decisions. Therefore it is a useful tool in assisting the government to balance socio-economic and health concerns. The fight against a new epidemic and how to reduce the number of deaths is the main purpose of this study. So, a new method to fight against epidemics is proposed. Detailed procedures of this method are explained.
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在管的開口端吹氣,不論他端為開啟或為閉塞,管內的空氣即會振動而發出聲音,這現象的解釋如下:如右圖為一端封閉的管,有一縱波由管的開口端進入管內。此縱波若為最簡單的正弦波。當波到達閉端時,即被反射,故管內會有兩方相反方向的進行波重疊。此兩進行波的振幅、頻率及波長均相等,此兩反向而行的波合成一駐波。
因閉端附近的空氣不能往閉端外移動,故其位移為零,即為縱波駐波的波節。而開口端附近的空氣,振動位移最大,故為波腹。由上圖得見,如管的一端封閉,管長為L,在管中形成駐波的條件為, L=λ/4、3λ/4、5λ/4 、、、或L=n λ/4(n=1、3、5、、、、)故閉管所產生的頻率f=V/λ=nV/4L(n=1、3、5、、、n=1 的頻率稱為基頻,n>1 的頻率稱為泛音),式中的V 乃聲波在空氣中的傳播速度(V=331+0.6t),測量L 及t,可得f。
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流量計在實驗室與工業領域裡是重要的儀器,如今已經有數十種依不同物理原理而發展出來的型式,可以配合多變的環境需求與測量條件而使用。然而,各種流量計所適用的範圍備受侷限。本研究主要目的在發展一種熱線式的渦流流量計,供給氣體之流量量測之用。透過自行製作儀器與設備:熱線測速儀(包括探針、探棒及電子處理器)和渦旋產生器(管道中含一三角形截面之鈍體,當流體通過時,在後方尾流產生週期性渦旋逸放)。由於熱線測速儀擁有偵測流體運動時高頻動態變化的能力(約為20000 Hz 以內),因此結合熱線測速儀與渦旋產生器,經適當的設計與調校,可以測得在不同流體流速時渦旋產生器的三角截面鈍體後方渦旋逸放的頻率。由於渦旋產生器的截面面積為固定值,因此可以從而計算出流量與渦旋逸放頻率的關係。經由嚴格的校準與驗證步驟,本研究的結果顯示自製的熱線測速儀擁有極佳的渦旋頻率偵測能力,所量測到的校準曲線顯示渦旋產生器的三角形截面柱所產生的渦旋逸放頻率與流量成線性關係。為了降低誤差,建議在0 ~ 40 CMM 之量測範圍內分成三條方程式來代表不同範圍內的校準曲線,最大誤差僅在5%以下。若需使用在不同的流量範圍時,僅需改變渦流產生器和幾何尺寸,以使渦旋逸放頻率適合於熱線測速儀的動態響應範圍即可。倘若商品化之後,可以實際應用於風扇流量量測、引擎進氣埠流量的測量等等應用。熱線測速儀本身也可作為風速計,適用於各種場合之風速量測。Flow meter is a instrument that is vital to the laboratory as well as the industrial related field. Based on different physical principles, tens of models that work in harmony with the diverse environmental demands and measurement conditions are developed to date. However, the application of varied flow meters is still under severe restriction. The purpose of this study is to develop a hot-wire type of vortex shedding flow meter for the use of flow rate measurement. Through the home-made apparatus and device, the hot-wire anemometer (includes probe, stem and electronic processor) and the vortex generator. (duct that contains triangle’s section of the bluff body. When fluid passes through, the wake behind produces periodical vortex shedding.) The ability of hot-wire anemometer when it detects the fluid moving changes of high-frequent movement is within 2000Hz, after appropriate design and adjustment, the combination of hot-wire anemometer and vortex generator may investigate the frequency of different flow rate that generated from the vortex shedding behind the bluff body of triangle section. The section area of vortex generator is constant value, thus it can calculate the relationship of flow rate and the frequency of vortex shedding. By means of strict calibration and test procedure, the results reveal that home-made hot-wire anemometer has excellent ability to detect the frequency of vortex shedding. The calibration curve indicates a linear relationship between the frequency of vortex shedding and flow rate. In order to reduce inaccuracy, it is suggested to classify three formulas to represent the flow rate that ranges from 0 ~ 40 CMM. The greatest inaccuracy is under 5%. When applied to different flow rate range, it only has to change the size of vortex generator only if the response frequency of hot-wire anemometer suit for the range of frequency of vortex generator. After commercialization, it can be applied to measure the flow rate of fans, flow rate of intake valve of engine, etc. Hot-wire anemometer also served as anemometer, which can be applied to wind velocity measurement in any situation.
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以圓錐套和熱電半導體來改善傳統電風扇效能的研究
電風扇在炙熱的夏日中為冷器以外不可或缺的生活用品。一個典型的電風扇是由架在可調高度鐵柱上的馬達及風扇構成。現行傳統電風扇有幾個缺點,一、馬達風扇(即重心)位置高,有易傾覆的缺點。二、風力分散,風速不高。三、吹出不可調室溫溫度的風。四、外觀呆板,傳統無奇。五、多噪音等。本研究根據這幾點傳統電風扇缺點,試著設計新的電風扇。首先將柱子移除使重心降至接近地面處。接著根據連續方程式(continuity equationρ1A1V1 =ρ2A2V2)製作圓錐狀「號角」裝置套於電風扇上以集中風力並減少噪音。最後企圖使用熱電半導體的致冷器降低輸出風的溫度。研究結果發現號角裝置有效達到預期的集中風力增加範圍目的。不幸發現以熱電半導體降溫的方式效率低且耗損過多能量所以可行性較低。雖然沒有降溫功能,本電風扇仍較傳統電風扇多出許多好處,例如加強的安全性、集中的風和強大擴充性。號角裝置可包含空氣清淨甚至音箱功能充當喇叭。Electric fans are a necessity during summer, especially in a hot and humid place such as Taiwan. A typical electric fan is primarily composed of an electric motor with fans mounted on a strut with user adjustable elevations. This setup presents several problems, including (a) the danger of an accidental tip-over due to the fan's elevated weight center (the heavy motor), (b) high wind dispersal rates, (c) room temperature winds, (d) excessive noise and (e) old, antiquated exterior appearance. This particular study attempts to alleviate all these problems. First the weight center is lowered to ground level by removing the entire strut and placing the motor close to the floor. Next by using calculations from the continuity equation(continuity equationρ1A1V1 =ρ2A2V2)a cone shaped “horn” device is placed over the fan in order to concentrate the wind, effectively increasing its speed while decreasing the audible noise level. Finally, an attempt was made to lower the temperature of the air in the interior of the horn by the placement of a thermoelectric semi-conductor cooling device. Our results were that the horn device worked, significantly lowered the wind dispersal rate and achieved an important objective. However, the thermoelectric cooling solution proved to be highly inefficient unless accompanied by precise wind speeds. Even without the cooling function, this new electric fan still has many distinct advantages over traditional fans such as improved safety, concentrated winds and high expandability. For instance, filters can be integrated to purify air, even an audio speaker can be made into the form of this fan.
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