翻訳と辞書 Words near each other ・ Differential graded algebra ・ Differential graded category ・ Differential graded Lie algebra ・ Differential graded scheme ・ Differential grasshopper ・ Differential group delay ・ Differential heat treatment ・ Differential ideal ・ Differential inclusion ・ Differential inheritance ・ Differential interference contrast microscopy ・ Differential invariant ・ Differential item functioning ・ Differential Manchester encoding ・ Difference and Repetition ・ Difference density map ・ Difference due to memory ・ Difference engine ・ Difference feminism ・ Difference gel electrophoresis ・ Difference hierarchy ・ Difference in differences ・ Difference in the depth of modulation ・ Difference list ・ Difference of Gaussians ・ Difference of Opinion ・ Difference of two squares ・ Difference polynomials ・ Difference quotient ・ Difference set 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 Difference density map ： ウィキペディア英語版 Difference density map In X-ray crystallography, a difference density map shows the spatial distribution of the difference between the measured electron density of the crystal and the electron density explained by the current model. Conventionally, they are displayed as isosurfaces with positive density—electron density where there's nothing in the model, usually corresponding to some constituent of the crystal that hasn't been modelled, for example a ligand or a crystallisation adjutant -- in green, and negative density—parts of the model not backed up by electron density, indicating either that an atom has been disordered by radiation damage or that it is modelled in the wrong place—in red. Difference density maps are usually calculated using Fourier coefficients which are the differences between the observed structure factor amplitudes from the X-ray diffraction experiment and the calculated structure factor amplitudes from the current model, using the phase from the model for both terms (since no phases are available for the observed data). The two sets of structure factors must be on the same scale. It is now normal to also include weighting terms which take into account the estimated errors in the current model: $C\_\; =\; (\; m\; |F\_|\; -\; D\; |F\_|\; )\; exp(\; 2\backslash pi\; i\; \backslash phi\_\; )$ where ''m'' is a figure of merit which is an estimate of the cosine of the error in the phase, and ''D'' is a scale factor. These coefficients are derived from the gradient of the likelihood function of the observed structure factors on the basis of the current model. 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「Difference density map」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.