奈米微粒因為粒徑很小而可能顯現出與巨觀材料性質不同的效應。在大氣中因為天然及人為因素亦產生相當多的奈米微粒，成為大氣氣膠中重要成分。本研究以電噴霧法製備不可溶TiO2 以及可溶甘露糖(D-Mannose)奈米微粒並以流動型雲霧室探討水及正丁醇蒸氣中所引起之非均勻相核凝機構。
TiO2微粒與甘露糖微粒無論在過飽和水或正丁醇蒸氣中，臨界過飽和度皆隨粒徑減小而增大。定性上與理論計算之趨勢相符合，但定量上仍有一段差距。有關電荷效應方面，TiO2和甘露糖微粒在水及正丁醇蒸氣中，不帶電微粒所需之臨界過飽和度皆大於帶電微粒，定性上和理論符合。
在電荷極性效應方面，不可溶TiO2帶單一負電荷微粒在水蒸氣中臨界過飽和度值較帶單一正電荷低；在正丁醇蒸氣中則相反，其結果定性上皆與理論符合。可溶甘露糖微粒帶單一負電荷微粒在正丁醇蒸氣中臨界過飽和度值較帶單一正電荷低，與理論預測矛盾。
至於可溶性微粒與不可溶性微粒比較方面，實驗結果與理論相符，可溶性微粒臨界過飽和度皆小於不可溶性微粒。
實驗值和理論值在定性上有誤差，推測造成差別之原因可能是受表面張力影響所致或是現有之核凝理論尚待進一步修正。

Nanoparticles may have a property different from the bulk due to such a small size. Recently, the subjects concerning their production, properties and applications have received extensively attention and been intensively investigated. On the other hand, nanoparticles are generated due to natural and anthropogenic activities, and become an important component of the atmospheric aerosols. A systematic study on the heterogeneous nucleation of water and n-butanol vapor on neutral and various single-charged nanoparticles of TiO2(6nm-30nm)/Mannose(8nm-25nm) is performed employing an electrospraying device and a flow cloud chamber (FCC).
The results show that the experimental Scr decreases with increasing particle size, at a rate in reasonable agreement with that predicted by Fletcher’s version of Volmer’s theory of heterogeneous nucleation.
The Scr of neutral and charged particles are slightly different. On the other hand, a charged effect on Scr is observed. The condensation on single- charged positive and single-charged negative particles are also examined. N-butanol vapor is more readily to condense on single-charged positive TiO2 particles and water vapor condense on single-charged negative TiO2 particles, at a rate in reasonable agreement with that predicted by Theory.
And N-butanol vapor is more readily to condense on single-charged negative Mannose particles. It is variance with theoretical predicted.
Solube particle Scr is smaller than insoluble particle Scr, in agreement with the theoretical prediction.
To make the theoratical curve agree well with the experimental data, a lower surface tension was required. However, this is inconsistent with the unknown curvature dependency of the surface tension. The discrepancy between the experimental and theoretical critical supersaturation values cannot be fully accounted for by the existing theory concerning the curvature-dependent surface tension yet.

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