翻訳と辞書 Words near each other ・ Product market ・ Product marketing ・ Product measure ・ Product metric ・ Product Miniature Company ・ Product naming ・ Product naming convention ・ Product numerical range ・ Product of experts ・ Product of group subsets ・ Product of groups ・ Product of Imagination ・ Product of rings ・ Product of Society ・ Product of the 80's ・ Product operator formalism ・ Product optimization ・ Product order ・ Product Perfect ・ Product pipeline ・ Product placement ・ Product Placement (album) ・ Product planning ・ Product proliferation ・ Product quality risk in supply chain ・ Product Recall ・ Product recall ・ Product Red ・ Product requirements document ・ Product rule Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Product operator formalism ： ウィキペディア英語版 Product operator formalism In NMR spectroscopy, the product operator formalism is a method used to determine the outcome of pulse sequences in a rigorous but straightforward way. With this method it is possible to predict how the bulk magnetization evolves with time under the action of pulses applied in different directions. It is a net improvement from the semi-classical vector model which is not able to predict many of the results in NMR spectroscopy and is a simplification of the complete density matrix formalism. In this model, for a single spin, four base operators exist: $I\_x$, $I\_y$, $I\_z$ and $E/2$ which represent respectively polarization (population difference between the two spin states), single quantum coherence (magnetization on the xy plane) and the unit operator. Many other, non-classical operators exist for coupled systems. Using this approach, the evolution of the magnetization under free precession is represented by $I\_z$ and corresponds to a rotation about the z-axis with a phase angle proportional to the chemical shift of the spin in question: $I\_x\; \backslash xrightarrow\; \backslash cos\; (\backslash omega\; \backslash tau)I\_x\; -\; \backslash sin\; (\backslash omega\; \backslash tau)I\_y$ Pulses about the x and y axis can be represented by $I\_x$ and $I\_y$ respectively; these allow to interconvert the magnetization between planes and ultimately to observe it at the end of a sequence. Since every spin will evolve differently depending on its shift, with this formalism it is possible to calculate exactly where the magnetization will end up and hence devise pulse sequences to measure the desired signal while excluding others. The product operator formalism is particularly useful in describing experiments in two-dimensions like COSY, HSQC and HMBC. == References == * * 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Product operator formalism」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.