作業中の電荷転向:擬似対称性の事例
Gábor Oszlányi1, András Süto, Mátyás Czugler
1Research Institute for Solid State Physics and Optics, H-1525 Budapest POB. 49, Hungary. go@szfki.hu
Journal of the American Chemical Society
|June 29, 2006
まとめ
チャージ・フリッピング (CF) は,X線微分法を用いた新型の結晶構造溶液法である. このアビニシオテクニックは,事前の情報なしに,擬似対称性のあるものであっても,複雑な構造を素早く解くことができます.
科学分野:
- クリスタログラフィーです.
- マテリアルサイエンス 材料科学
- コンピューティング・ケミストリー
背景:
- 伝統的な結晶構造溶液法では時間がかかり,専門家の介入が必要になります.
- 擬似対称性または曖昧な空間群を持つ複雑な構造は,従来のアプローチに重大な課題をもたらす.
研究 の 目的:
- 結晶構造溶液のチャージ・フリッピング (CF) アルゴリズムの実用的な応用と有効性を実証する.
- CFが困難な構造を素早く,人間の関与なしに解決する能力を示します.
主な方法:
- チャージ・フリッピング (CF) アルゴリズムは,単結晶X線微分データを用いた反復的なab initio方法である.
- リアル空間と相互空間を交互に変えて,電子密度の徴候を修正し,観察された構造因子モジュリを強制する.
主要な成果:
- CFアルゴリズムは,偽対称性の大きな,軽原子の非中心対称構造を数秒で成功裏に解きました.
- 100%の成功率を達成し,すべての出発点は正しい解決策につながり,堅実性を実証しました.
- CFは,結晶学における一般的な課題である翻訳的擬似対称性を効果的に処理しました.
結論:
- チャージ・フリッピング (CF) メソッドは,結晶構造溶液のための非常にシンプルで効率的なアビニシオアプローチを提供します.
- CFは,速度と自動化において,特に複雑な構造物に対して,従来の方法よりもはるかに優れています.
- CFは,標準的な結晶学ソフトウェア,特に擬似対称性や曖昧な空間群を持つ構造のための貴重な補完ツールです.
関連する概念動画
Transformers
A device that transforms voltages from one value to another using induction is called a transformer. A transformer consists of two separate coils, or windings, wrapped around the same soft iron core. However, they are electrically insulated from each other.
The iron core has a substantial relative permeability. Therefore, the magnetic field lines generated due to the current in one winding are almost entirely confined within the core, such that the same magnetic flux permeates each turn of both...
The iron core has a substantial relative permeability. Therefore, the magnetic field lines generated due to the current in one winding are almost entirely confined within the core, such that the same magnetic flux permeates each turn of both...
Source Transformation
Source transformation is a fundamental technique employed in circuit analysis, offering a valuable tool for simplifying complex electrical circuits. This technique involves the replacement of either a voltage source in series with a resistor by a current source in parallel with a resistor, or vice versa. The key concept here is that when the original sources are deactivated (turned off), the equivalent resistance at the circuit's end terminals remains the same.
It is essential to note that when...
It is essential to note that when...
Three-Phase Voltages
A three-phase generator produces three voltages that are equal in magnitude but have a phase difference of 120 degrees. This identical magnitude and equal phase separated voltages are known as the balanced voltages and help to minimize power loss while ensuring a steady delivery of energy to connected loads. As voltage sources in a three-phase system can be configured in a wye or a delta formation, the loads connected to these systems can also be arranged in either configuration. This...
The Delta-to-Delta Circuit
In a delta-delta configuration, the source and the load are connected in a delta manner, forming a closed loop that divides the network into three distinct phases. This configuration makes the phase voltages identical to line voltages. Assuming the sources are in positive sequence, the phase voltages can be expressed directly without having a neutral wire.
The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
Shunt Admittances
Shunt admittances play a crucial role in the analysis of transmission lines, particularly for three-phase systems with neutral conductors. When a uniformly charged conductor is positioned above the Earth, it induces an equal but opposite charge on its surface. This interaction creates electric field lines between the conductor and the Earth.
To model this effect, the method of images is employed. This method involves replacing the Earth with an image conductor that mirrors the original...
To model this effect, the method of images is employed. This method involves replacing the Earth with an image conductor that mirrors the original...


