"原子結晶核形成における反転可能な乱雑・秩序の移行"に関するコメント

Cheng-Long Yu¹, Hang Cheng¹, Yong Qi²

¹School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.

Science (New York, N.Y.)

|March 24, 2022

まとめ

この研究は,物質核の可逆変動の解釈に異議を唱え",マジックナンバー"とシグモイド関数が誤解を招く可能性があると主張している. また,理論的な分析では結晶の形状効果が無視されていることが判明しました.

科学分野:

材料科学
クリスタルグラフィー
化学物理学

背景:

核形成中に無秩序状態と結晶状態の間の可逆的な変動が報告されています.
これらの変動の解釈は,特にサイズに依存する現象に関して,核化のプロセスを理解するために重要である.

研究の目的:

Jeon et al が提示した方法論と結論を批判的に評価する. 原子核のダイナミクスについて
核化データを分析する際の"マジックナンバー"とシグモイド関数の使用から生じる誤った解釈に対処する.
結晶の形状効果を理論的な核化モデルで考慮する重要性を強調する.

主な方法:

核化に関するデータと理論モデルの再分析
サイズ範囲分離のための"マジックナンバー"とシグモイド関数の適用を批判する.
結晶形態が核化現象に及ぼす影響の検討.

主要な成果:

シグモイド関数を持つパーティションサイズ範囲に"マジックナンバー"を使用することは,潜在的に誤解を招くものである.
参考研究における図3Bは誤って示されているようです.
原稿の理論的な分析では,結晶の形が重要な影響を与えるのを無視した.

結論:

核形成中の可逆変動の現在の理解は,これらの発見に基づいて改訂を必要とするかもしれません.
正確な核化分析には,結晶の形を含むより厳格な理論的枠組みが必要である.
核形成におけるサイズ依存現象と形態学の役割を明らかにするために,さらなる調査が必要である.

さらに関連する動画

08:55

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Published on: June 7, 2018

8.6K

09:52

Optimizing the Growth of Endothiapepsin Crystals for Serial Crystallography Experiments

Published on: February 4, 2021

2.4K

関連する概念動画

01:10

Recrystallization: Solid–Solution Equilibria

1.2K

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...

1.2K

01:25

Crystal Growth: Principles of Crystallization

2.9K

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...

2.9K

02:33

Phase Transitions: Sublimation and Deposition

18.3K

Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...

18.3K

01:21

Polymer Classification: Crystallinity

3.2K

Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...

3.2K

01:34

Woodward–Hoffmann Selection Rules and Microscopic Reversibility

3.3K

Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...

3.3K

02:39

Phase Transitions: Melting and Freezing

13.4K

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...