Changeset 30b60d2 in sasmodels for sasmodels/models/rpa.py
- Timestamp:
- Sep 5, 2017 12:39:41 PM (7 years ago)
- Branches:
- master, core_shell_microgels, costrafo411, magnetic_model, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests
- Children:
- 3a45c2c
- Parents:
- 64eecf7
- File:
-
- 1 edited
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sasmodels/models/rpa.py
r4f9e288 r30b60d2 30 30 These case numbers are different from those in the NIST SANS package! 31 31 32 The models are based on the papers by Akcasu et al. [#Akcasu]_and by33 Hammouda [#Hammouda]_assuming the polymer follows Gaussian statistics such32 The models are based on the papers by Akcasu *et al.* and by 33 Hammouda assuming the polymer follows Gaussian statistics such 34 34 that $R_g^2 = n b^2/6$ where $b$ is the statistical segment length and $n$ is 35 35 the number of statistical segment lengths. A nice tutorial on how these are 36 36 constructed and implemented can be found in chapters 28 and 39 of Boualem 37 Hammouda's 'SANS Toolbox' [#toolbox]_.37 Hammouda's 'SANS Toolbox'. 38 38 39 39 In brief the macroscopic cross sections are derived from the general forms … … 49 49 are calculated with respect to component D).** So the scattering contrast 50 50 for a C/D blend = [SLD(component C) - SLD(component D)]\ :sup:`2`. 51 * Depending on which case is being used, the number of fitting parameters can 51 * Depending on which case is being used, the number of fitting parameters can 52 52 vary. 53 53 … … 57 57 component are obtained from other methods and held fixed while The *scale* 58 58 parameter should be held equal to unity. 59 * The variables are normally the segment lengths (b\ :sub:`a`, b\ :sub:`b`, 60 etc) and $\chi$ parameters (K\ :sub:`ab`, K\ :sub:`ac`, etc). 61 59 * The variables are normally the segment lengths ($b_a$, $b_b$, 60 etc.) and $\chi$ parameters ($K_{ab}$, $K_{ac}$, etc). 62 61 63 62 References 64 63 ---------- 65 64 66 .. [#Akcasu] A Z Akcasu, R Klein and B Hammouda, *Macromolecules*, 26 (1993) 67 4136. 68 .. [#Hammouda] B. Hammouda, *Advances in Polymer Science* 106 (1993) 87. 69 .. [#toolbox] https://www.ncnr.nist.gov/staff/hammouda/the_sans_toolbox.pdf 65 A Z Akcasu, R Klein and B Hammouda, *Macromolecules*, 26 (1993) 4136. 66 67 B. Hammouda, *Advances in Polymer Science* 106 (1993) 87. 68 69 B. Hammouda, *SANS Toolbox* 70 https://www.ncnr.nist.gov/staff/hammouda/the_sans_toolbox.pdf. 70 71 71 72 Authorship and Verification
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