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asked in 科學及數學化學 · 1 decade ago

咩叫aerogel ?

咩叫aerogel ? 唔好只係答我氣凝膠

要詳細少少

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  • 1 decade ago
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    Aerogel is a low-density solid-state material derived from gel in which the liquid component of the gel has been replaced with gas. The result is an extremely low density solid with several remarkable properties, most notably its effectiveness as an insulator.

    Aerogel was first created by Steven Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid inside a jam (jelly) jar with gas without causing shrinkage.[2][3]

    Aerogel is not like conventional foams, but is a special porous material with extreme microporosity on a micron scale. It is composed of individual features only a few nanometers in size. These are linked in a highly porous dendritic-like structure.

    Unusual Properties : low thermal conductivity, refractive index and sound speed - in addition to its exceptional ability to capture fast moving dust.

    Aerogel is made by high temperature and pressure-critical-point drying of a gel composed of colloidal silica structural units filled with solvents. Aerogel was prepared and flight qualified at the Jet Propulsion Laboratory (JPL). JPL also produced aerogel for the Mars Pathfinder and Stardust missions, which possesses well-controlled properties and purity.

    2008-03-15 16:13:02 補充:

    氣凝膠的密度爲每立方厘米3毫克,相當于玻璃的千分之一。氣凝膠看上去呈雲霧狀,淡藍色。

    氣凝膠的兩個特點:輕,固態。

    看似脆弱不堪,其實非常堅固耐用,能承受烈性炸藥的爆炸沖擊波,還能隔絕1300℃的高溫。

      盡管氣凝膠被歸類爲固體,但其中99%的物質都是氣體。科學家說,由于材料上有上百萬個小孔和皺褶,如果把1立方厘米的氣凝膠全部展開的話,它可以覆蓋一個足球場。

      氣凝膠是從一種矽膠中抽去水分,然後注入二氧化碳等氣體制成的。其實,早在1931年,一位美國化學家就發明了這種材料,但早期制成的材料非常脆弱,而且成本很高,因此使用只局限在實驗室中。

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