関連する実験動画
Updated: Jun 7, 2026

10:56
Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures
Published on: May 21, 2014
閉じ込められた幾何学における超冷却水のダイナミクス
1Department of Experimental Physics, Chalmers University of Technology, Goteborg, Sweden. f5xrb@fy.chalmers.se
Nature
|February 5, 2000
まとめ
研究者は,ダイエレクトリックスペクトロスコーピーを用いて超冷却水の性質を研究した. ヴェルミキュライト粘土に閉じ込められた水は"脆い-強い"移行を明らかにし,水のユニークな行動に関する理論を支持しました.
科学分野:
- 物理化学 物理化学
- マテリアルサイエンス 材料科学
- 凝縮物質物理学 凝縮物質物理学
背景:
- 超冷却により,液体は凍結点以下に存在し,ガラスを形成する可能性があります.
- ガラスを形成する液体は,温度に依存する粘度とリラックス時間 (tau) を表します.
- 超冷却状態での水の振る舞いは議論され,228 K. 周りの"脆い-強い"移行が提案されています.
研究 の 目的:
- 超冷却水のリラクゼーションダイナミクスを広範な温度範囲で調査するために.
- 低温で水の結晶化によって生じる実験的限界を克服するために.
- 提案されている水における脆性から強さの移行に賛成または反対の証拠を提供すること.
主な方法:
- ブロードバンド介電スペクトロスコピーは,リラックス時間を測定するために使用されました.
- 超冷却された水は,層層のヴァルミキュライト粘土のマトリックスの中に閉じ込められました.
- ヴァルミキュライトの幾何学的な閉じ込めとナトリウムイオンが結晶化を阻害した.
主要な成果:
- アレニウス温度に依存したリラックスプロセスが観察されました.
- この振る舞いは",強い"液体の分類と一致しています.
- 発見は,結晶化のために通常アクセスできない温度範囲で観察されました.
結論:
- この研究は,超冷却水における"脆弱から強い"移行の存在を裏付けている.
- 深く超冷却された散布水は,より高い温度で脆弱な行動と対照的に強い特性を示す.
- ヴァルミキュライト粘土に閉じ込めることは,超冷却水の動態を研究するための効果的な方法です.
関連する概念動画
States of Water
Water exists in any one of the three classical states: solid (ice), liquid (water), and gas (steam or water vapor). The state of water depends on i) the intermolecular forces that draw molecules together and ii) the kinetic energy that leads to movements that pull them apart.
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
Phase Transitions: Vaporization and Condensation
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
Newtonian Fluid: Problem Solving
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
Capillarity in Fluid
Capillarity describes the movement of liquid in small spaces without external forces acting on it. The capillarity is driven by surface tension and adhesive interactions between the liquid and surrounding solid surfaces. This effect is often seen in narrow tubes, porous materials, and fine particles.
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
Dimensionless Groups in Fluid Mechanics
Dimensionless groups in fluid mechanics provide simplified ratios that help analyze fluid behavior without relying on specific units. The Reynolds number (Re), which represents the ratio of inertial to viscous forces, distinguishes between laminar and turbulent flows, making it essential in the design of pipelines and aerodynamic surfaces. The Froude number (Fr), the ratio of inertial to gravitational forces, is particularly useful in predicting wave formation and hydraulic jumps in...

