跳到主要內容

臺灣博碩士論文加值系統

(35.173.42.124) 您好!臺灣時間:2021/07/24 10:29
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

我願授權國圖
: 
twitterline
研究生:余福芝
研究生(外文):Yu, Fu-Chih
論文名稱:La3CaBa3Cu3Oy超導體與水溶液的反應
論文名稱(外文):The reaction of La3CaBa3Cu7Oy superconductor with water
指導教授:高惠春, 王啟銘
指導教授(外文):Kao Huey-Chuen I., Wang Chi-Ming
學位類別:碩士
校院名稱:淡江大學
系所名稱:化學學系
學門:自然科學學門
學類:化學學類
論文種類:學術論文
論文出版年:1996
畢業學年度:84
語文別:中文
論文頁數:117
中文關鍵詞:超導體與水反應磁化率導電性反應方程式動力學
外文關鍵詞:superconductorwatersusceptibilityconductivityequationkinetic
相關次數:
  • 被引用被引用:1
  • 點閱點閱:224
  • 評分評分:
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
錠狀La-3137樣品在浸泡20分鐘後,其Tc(zero)隨浸泡水溫上升而下降,
而295K電阻率則隨水溫上升而增加.在80C水溫下,10K磁化率及XRD圖相對
強度皆隨浸泡時間增加而減小.若將樣品表面磨掉後,其Tc(onset)與未泡
前相同,證明樣品內部並未被侵蝕,僅表面生成非超導相.導電量測結果,包
含Tc(zero)降低率,及250K電阻增加率,都顯示La-3137比Y-123反應性小.
粉末La-3137樣品與水反應,生成大量Ba2+及Ca2+離子,並產生OH-,使開放
系統中溶液pH值增至9,隨後又因與空氣中CO2反應生成BaCO3及CaCO3,使溶
液pH值逐漸下降.推測La-3137與水反應方程式為:La1.29Ca0.43Ba1.29Cu3
O6.64(s)+1.72H2O=0.43Ca(OH)2(aq)+1.29Ba(OH)2(aq)+0.65La2CuO4(
s)+2.36CuO(s)+xO2(g),反應動力學研究顯示,La-3137和Y-123的起始反應
速率定率式為R=k[A]o[H]o,其中La-3137的a=1.0,b=0.5,Y-123則是a=1.0,
b=0.3,此二種超導體皆是與粉末表面積有關的一級反應.La-3137與Y-123
之活化能及pre-exponential factor 分別為83.6kJ/mole,2*10^11M0.5
min-1cm-2與49.9kJ/mole,1.33*10^6M0.7min-1cm-2.在pH=4-9及溫
度=10-40C之條件下,La-3137的反應性皆比Y-123慢.La-3137在水中的安定
性高於Y-123與其所含之鹼土金屬離子比例有關.
On reaction of La-3137 pelletwith water for 20 min.,its Tc(zero)
was decreased,but the others were increased with increasing
water temperature. when the sample was soaked in 80C water,
magnetic susceptibility at 10K and the relative inetnsity of
the XRD pattern were decreased with increasing soaking period.
If the reacted surface was removed, Tc(zero) of the residual
sample was not changed, suggesting that during the reaction,
nonsuperconducting compounds were only formed on the surface,but
the inside of the sample remained intact. Conductivity
meaurements showed that reaction rate of La-3137 was slower than
that ofthat of Y-123. On reacting the La-3137 powder with water,
Ba2+,Ca2+ and OH- ions were obtained and pH of the solution was
increased repidly to 9.In the open system, Ba2+ and Ca2+ ions
would further react with the atmosphericCO2 forming unsoluble
BaCO3 and CaCO3 and the pH of the solution was slowly decreased.
The equation of formula for one unit-cell of of La-3137 reacted
withwater was deduced as follow:La1.29Ca0.43Ba1.29Cu6.64(s)+1.72
H2O=0.43Ca(OH)2(aq)+1.29Ba(OH)2(aq)+0.65La2CuO4(s)+2.36CuO(s)+
xO2(g), Kinetic studies showed that the initial rate could be
expressed as R0=k[A]o[H]o,where a=1.0,b=0.5 for Y-123.Both
superconductors had first order reaction with respect to the
surface area.Activation energy and pre-expential factor of
La-3137 and Y-123 was 83.6kJ/mole,2*10^11M0.5min-1cm-2 and
49.9kJ/mole,1.33*10^6M0.7min-1cm-2,respectively. Under pH=4-9
and temp=10-40C,the reactivity of La-3137 with water was less
than that of Y-123. Stability of these superconductors was
related to the mole fractionof Y-123.Stability of these
superconductors was related to the mole fraction of the alkaline
earth elements in these samples.
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top