関連する実験動画
Updated: Feb 19, 2026

16:24
Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
19.3K
氷の核形成における堆積障害の役割
Laura Lupi1, Arpa Hudait1, Baron Peters2
1Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, USA.
Nature
|November 10, 2017
まとめ
クラシックな核形成理論は 氷の核形成率を過大評価しています 新しい発見により 積み重ねられた氷は 六角形の氷よりも安定し 気候や天気予報に影響します
科学分野:
- 物理化学
- 大気科学
- 材料科学
背景:
- 正確な気候と天気予報は 氷の核化率の予測に依存しています
- クラシックな核化理論 (CNT) は,ナノメートルサイズの結晶体について六角形の氷の構造を想定しており,これは現実を反映していない可能性があります.
研究 の 目的:
- 六角氷の安定性を調べるため
- 氷の結晶質構造が核形成率と気候モデルに与える影響を決定する.
主な方法:
- 稀なイベントのサンプリングと自由エネルギー計算を mWの水モデルで利用した.
- 10万個の氷の結晶の 安定性を分析した
主要な成果:
- 積み重ねの乱れた氷は,少なくとも10万個の分子までの結晶体の安定段階です.
- 230 Kでは,積み重ねの乱れを伴う臨界結晶は,六角型よりも14 kJ/mol安定している.
- 積み重ねの乱れによる氷の核化率は,CNTの予測より3倍以上高い.
結論:
- 氷結晶の大きさに依存する安定性を説明するために,古典的な核化理論には修正が必要です.
- この発見は 雲の形成モデリングと 氷の粒子の数の予測に 影響を及ぼします 特に気温が高くなるとです
関連する概念動画
Colloidal precipitates
6.6K
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
6.6K
Recrystallization: Solid–Solution Equilibria
4.1K
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
4.1K
Crystal Growth: Principles of Crystallization
5.3K
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
5.3K
Predicting Products: SN1 vs. SN2
17.4K
Nucleophilic substitution reactions of alkyl halides can proceed via an SN1 or an SN2 mechanism. While in SN2 reactions, the nucleophile attacks the substrate simultaneously as the leaving group departs, in SN1 reactions, the substrate first dissociates to give the carbocation intermediate. Various factors such as the structure of the substrate, the strength of the nucleophile, and the nature of the solvent promote one mechanism over the other.
With increased substitution on the alkyl halide,...
With increased substitution on the alkyl halide,...
17.4K
Ionic Crystal Structures
18.3K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
18.3K
Metallic Solids
21.0K
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
21.0K

