多重電極並聯情況下交、直流電解水的比較研究
The temperature of the water was commonly higher and both of electrodes were oxidized during electrolysis by using alternating current, but the above happenings were only found at the positive electrode by using direct current. It can be explained by the principle of the microwave stove. The exchange of the current causes the water molecules to release heat. The strength and weakness of electrolytes, the length and width of the electrodes, and the frequency of the alternating current can affect the rate of electrolysis of water. Commonly speaking, the stronger the electrolyte is, the faster the rate of electrolysis will be. NaOH and HNO3 are strong electrolytes, but the amount of the gas is zero during electrolysis by using alternating current. Maybe both of electrolytes react with stainless-steel electrodes to form some kinds of protective layers to affect the conduction of current. When copper bars, carbon bars, and iron nails are used as electrodes, either the alternating current or direct current is used, the amount of the gas is very small. Maybe these electrodes react with oxygen produced during electrolysis to form oxidized layers to block the conduction of current. Long and wide electrodes produce more amount of the gas. The amount of the gas increases when the frequency of the alternating current increases. The longer the distance between electrodes is, the smaller the amount of the gas will be. The smaller the angle between electrodes is, the smaller the amount of the gas will be, too. When the number of multiple electrodes in parallel increases, the total amount of the gas almost increases. The amount of the gas is smaller at the farther electrode. The amount of the gas at the electrode at the same distance becomes smaller when the number of multiple electrodes in parallel increases. At the same voltage, the effective current of the alternating current is about 0.707 of that of direct current. So we can predict that the total amount of the gas elect rolyzed by alternating current must be about 0.707 of the total amount of the gas electrolyzed by direct current. When we used stainless-steel electrodes and the electrolyte- H2SO4, we found the ratio was about 0.4286. Maybe the system of the electrolysis of water doesn’t obey the ideal linear system of Ohm’s Law and some part of electrical energy is wasted by increasing the temperature of the water and the oxidization of electrodes.
交流電解普遍水溫較高且兩極都有被氧化現象，直流電解則只有正極有上述現象，可能是交流電有類似微波爐的原理，電流交替時造成水分子震盪發熱。電解質強弱、電極種類、電極長短粗細、交流電頻率會影響電解水速率：強電解質較快，但NaOH 、KNO3 雖是強電解質，在交流電解時，氣體產生量幾乎是零，這可能是他們與不銹鋼電極反應形成某種保護層而影響導電；以銅棒、碳棒、鐵釘為電極時，不管是交流電或直流電，氣體體積都很小，這可能是這些電極和產生的氧氣反應，形成氧化層阻礙了導電；長的和粗的電極氣體產生量較多；交流電頻率越大，則電解所產生的氣體量也隨之增加；電極之間的距離越大兩極的氣體體積越小；兩電極之間的角度越小，兩極的氣體體積越少；多重電極並聯的個數越多，總氣體體積約略越大，距離越遠的氣體體積越小，同距離的氣體體積隨並聯的個數越多氣體體積越小。在相同電壓下，交流電輸出的均方根電壓(電流)為直流電電壓(電流)的0.707 倍(1/√2)，所以推測交、直電解水的氣體總體積比值也應為0.707，但我們以不銹鋼為電極、H2SO4 為電解液下比值為0.4286，這可能是本電解水系統並非為遵守歐姆定律的理想線性系統，且電解水時部分電能被消耗在水溫的升高及電極的氧化上。
吸管笛的諧音之研究與發展
吹長笛時，按同一按鍵，以大小不同的力量去吹，會引發不同頻率的泛音，而通常越用力吹，引發泛音的頻率越高，所以我們想了解為什麼越用力，泛音的頻率會高，其間的關係究竟是什麼？風經過管口會產生各種頻率的噪音，其中某些特定頻率的聲音會因為會在管內形成駐波而放大，所以我們只能聽到某些特定頻率的聲音。當風速增加時，會在管口形成渦漩逸放的紊流現象。其渦漩頻率與流速成正比（註一）。我們以塑膠管實驗。發現以特定的風速引發該基音後，繼續增加風速，當風速達某一定強度時，才會躍遷為下一個泛音的頻率。這個現象告訴我們：在一封閉管下，風速與泛音的關係並非「線性遞增」，而是越「躍遷遞增」的關係。另一個實驗測量不同管長、其諧音之頻率的關係，我們可以得知，越短的管子，因為相鄰兩泛音間頻率差較大，越不易激發更高階泛音。經由這些實驗結果，我們能夠推論：當管子越長、基音頻率越低時，諧音間頻率的差距相對越小，繪出的風速－頻率關係圖應更加顯示了風速與頻率呈正比關係。未來我們可以以閃頻器觀測紊流渦漩的產生，再變化至不同吹入角度，及各式管口造形，這些實驗能協助我們更進一步了解樂器的發聲原理，甚至開發一個以聲音頻率測量風速的儀器。註一：林婉如、張?文2006 國際科工程組佳作作品。When we press the same key and blow a flute using different strengths, we can get different overtones. Usually, the harder we blow the flute, the high the frequency we get. We want to understand why we get a higher frequency when we blow harder into the flute and to understand the relationship between them. When wind passes through the mouthpiece, many kinds of noises will be produced. Some of the frequencies will expand because they will form standing waves in the tube. Therefore, we can only hear certain frequencies. As wind speed increases, a turbulence of the vortex shedding will be formed. The frequency of the vortex shedding and wind speed will be in a direct ratio. We experiment with plastic tubes. When we increase the wind speed and get certain magnitudes, the frequency will jump to the next overtone. The phenomenon shows that the relation, in a closed tube, between wind speed and harmonics is not a linear increase but a transition increase. In another experiment, we measured the relationship between wind speed and different lengths of tubes. We can infer that the shorter the tube, the higher high-frequency harmonics can be produced. Through these experiments, we come to the conclusion that the longer the tube, the lower frequency of the fundamental tone we get and the discrepancy in frequency between harmonics is smaller. Then we make a diagram between wind speed and frequency that indicates that there is a direct ratio between wind speed and frequency. In the future, we can use “” to observe the production of turbulence. Then we can switch to different angles when we blow into flutes. Otherwise, we can experiment with different shapes of mouthpieces. These experiments can assist us to understand more how the instrument sounds. We can develop a device measuring wind speed with frequency.
氧化壓力影響基因轉換表現對脂肪分化之作用
細胞脂肪分化是造成肥胖、骨質疏鬆、和糖尿病的重要前置因素。我們若要維持良好身材又想省去減肥藥的問題，那麼我們必須了解造成脂肪化的原因，才可能擁有好的預防之道。利用人類骨髓間質細胞可以分化成骨質與脂肪等細胞的特性，我們研究氧化壓力對間質細胞\r Ras基因轉換表現後骨質與脂肪分化的影響。結果發現以添加超氧根 (O2-，l5nM)形成氧化壓力，可促進正常Ras基因表現的間質細胞朝骨質分化;相反地，超氧根會促進\r Ras基因突變而不表現的細胞，朝向脂肪分化的現象。進一步研究其作可原理，發現氧化壓力可促進 RaS蛋白質啟動細胞外訊息活化酵素(ERK)，接著驅動骨質轉錄因子(CBFA1)表現，再到骨鈣蛋白質與骨結節形成。而抗氧化酵素(超氧根轉化酵素;SOD,5OOU/ml)的作用，可以抑制正常Ras基因細胞氧化壓力下骨質分化的進行;但不能防止氧化壓力促進Ras基因突變細胞，朝向脂肪分化的作用。總結而言:Ras基因的表現與否，是決定脂肪分化的關鍵切換點;也是影響氧化壓力對間質細胞朝骨質分化的樞紐。這種基因與氧化壓力互動影響骨質與脂肪分化的剖析，將有助於提醒人們:使用抗氧化劑來調節抗衰老、肥胖、和美容時，必須是在不同情況和不同基因體質的人，有所不同。
\r Human\r mesenchymal stem cells are able to differentiate into bone, muscle, cartilage or\r fat tissues. Our preliminary study with human mesenchymal cell line (HS-5) showed\r that HS-5 cells could differentiate to bone, cartilage and muscle but not fat cells\r as determined by histochemical staining of phenotypes. We have further studied the\r influence of oxidative stress on the switch between bone and fat cell differentiation.\r Results showed that oxidative stress started with exogenous superoxide, produced\r by the interaction of xanthine oxidase and hypoxanthine, promoted the differentiation\r of osteogenic lineage showing expression of osteocalcin and bone nodule formations.\r The mechanism was investigated and superoxide was found to induce ERK (extracellular\r regulated signal kinase) activation; and then the expression of osteogenic specific\r transcriptional factor (CBFA1). A plasmid containing ras-mutant (Ser 17 Asn) which\r can inactivate the expression of ERK was transfected into the HS-5 cells for studying\r the influence of oxidative stress on ras-mutated mesenchymal cells. Surprisingly,\r it was found that oxidative stress did not promote osteogenesis but it enhanced\r adipogenesis from the ras-mutated HS-5 cells. Further studies indicated that superoxide\r neither induced ERK activation nor CBFA1 expression, but it did enhance expression\r of adipogenic specific transcriptional factor (C/EBPα) and lipoprotein lipase in\r the ras-mutated mesenchvmal cells. Taken together, the study model to induce the\r bone cell differentiation from human mesenchymal stem cells may be employed to make\r bone cells for tissue engineering.
台北盆地的熱島效應及其對環境的影響
本研究主要是以台北市中心的氣溫觀測站，以及市區外圍東邊的汐止，南邊的屈尺，以及西邊的山佳等三個氣溫觀測站，從1998 年至2004 年的七年期間的氣溫資料中，來探討台北地區的熱島效應現象。這個研究的結果發現，台北市區與周遭鄰近地區確實會因為熱島效應的影響而產生1~2℃的溫差。這個溫差在白天時不甚明顯，在中午過後，便由台北市中心逐漸向郊區遞減，形成類似同心圓狀的分布。溫差最大值發生在夜晚，使得台北地區晚間宛如一座夜晚增溫的城市，同時夏季的熱島效應又較冬季顯著，氣溫又逐年遞升，造成夏季台北市區的高溫屢創新高，將是未來都市發展的危機。This study is focused on the urban heat island effect of Taipei Basin, northern Taiwan. The hourly temperatures of Taipei meteorological station and three rural sites eastern Hsi-Chih, southern Cyu-Chih and western San-Chia, were compared from 1998 through 2004 to illustrate the temperature differences between city center and surrounding country areas. The results show that a difference of 1~2℃ exists between city center and surrounding country areas, indicating the extent of urban heat island effect in the Taipei Basin. The daily temperature contours show a clear high-temperature bull’s eye at the city center during the midnight, implying the high latent heat trapped by the dense and high rise buildings. This phenomenon is not sharp in the high noon due to the reduction of temperature difference between city center and surrounding country areas. The heat island effect is most prominent in the summer than that of the winter. Along with the increasing temperature-difference trend through years, the summer times often experience record-breaking heat waves and pose great risks for the city development in the future.
國王的海市蜃樓
在夏日的午後，在炎熱的柏油路面上很容易可觀察到遠方的 路面上，出現如鏡子般的倒影，看起來彷彿前方有一灘水，但當 我們向前進一些時，倒影卻突然消失了，這個現象，一般稱為海 市蜃樓。 一般解釋海市蜃樓的成因，都是由於在上層的低溫空氣，和 在下層靠近路面的高溫空氣，因密度的不同，以致於折射率的漸 層差異，繼而產生全反射。 但我們觀察發現，地面與上層空氣的溫差，並非柏油路面上 假積水現象及倒影出現的必要條件；反而和入射光的角度、路面 的平坦程度及路面的性質有關。我們提出了粗糙面在入射光的入 射角接近90度時，可發生單向反射的模型。並由實驗來驗證假積 水現象及倒影主要的成因是「柏油路面的單向反射」而非「空氣 的折射與全反射」。 Under the scorching sunshine, we can see the reflection on the tarmac in the distance just like a water puddle on the road. And the water also reflects the people and object nearby. But, in fact, the tarmac road over there is very hot and dry. Therefore we call the phenomenon as the “false water puddle on the tarmac.” According to the textbook , the main reason for “false water puddle on the tarmac” is that the temperature difference leads to the refraction of the light and causes the phenomenon. However, from our observation, the theory still can’t explain some phenomenon, For example, the “false water puddle on the tarmac” remains to appear when the wind blows fiercely. Even with little temperature different at night the phenomenon is still obvious. Therefore, in our opinion, the temperature different of the air is not a necessary condition of “ the false water puddle on the tarmac.” We bring up the model to explain the phenomenon that when the incident angle of the light approach 90 degrees, the light will result in one-way reflection. According to the model, furthermore, we make experiments at midnight and at dawn. The result of the experiment assures us the hypothesis of the model, Consequently, we hold the ideal that the main condition of the “false water puddle on the tarmac.” Is not because of the refraction and the total reflection but because the light reflects off the road and result in the one-way reflection on the tarmac road.
「從害羞到大方需要多少時間」(環境因子對含羞草開葉時間的影響)
含羞草會因為受到各種不同外界刺激(光照、外力等等)，而造成膨壓改變。外 觀上表現出葉片閉合或有葉柄下垂的現象。其中含羞草處在黑暗的環境下一段時 間後，會做出睡眠運動。當它重新暴露於光照之中，將會需要一段時間以恢復原 先葉片張開的樣子。這個實驗是研究不同類型的環境因子(主要是光照和溼度)在打 破睡眠運動之後，對其葉片復原時間所造成的影響。我們針對上述環境因子在不 同狀況時，進行我們的實驗上百次，進一步得到了多項的數據。也在實驗中，為 了精確了解整個恢復的程序，而將恢復程序程序做成書面說明。以下是我們所紀 錄與分析完數據後的結果，以及我們在實驗期間，進行一些不同的實驗嘗試，所 發現不同於表面所見的驚人事實。 The mimosa can accept plenty of stimulation (light, force, etc), which results in the change of turgor pressure, and on outward appearance, it shows the phenomenon that the leaves become closed or that the stalks get pendent. Among the stimulation, the mimosa will undergo nyctinasty when it is left in the dark for a period of time, in order to enable it to be exposed to the light once more, which requires certain time. This experiment is based on how different kinds of elements of the environment (primarily light and hydro level) effects the rehabilitation time after the nyctinasty is broken. A large number of data are gained after experimenting on it for hundreds of times. Steps of habilitation are also made into illustration in writing, so as to understand the whole steps accurately in the experiment. Below are our records and analysis based on the data, including a few special experimental tries during our working time, in which some surprising facts that were discovered are different from what are seen on the surface.