Changeset 40a87fa in sasmodels for sasmodels/models/stacked_disks.py
- Timestamp:
- Aug 8, 2016 11:24:11 AM (8 years ago)
- Branches:
- master, core_shell_microgels, costrafo411, magnetic_model, release_v0.94, release_v0.95, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests
- Children:
- 2472141
- Parents:
- 2d65d51
- File:
-
- 1 edited
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sasmodels/models/stacked_disks.py
r42356c8 r40a87fa 14 14 of the q vector which is defined as 15 15 16 .. math:: 17 18 q = \sqrt{q_x^2 + q_y^2} 16 .. math:: q = \sqrt{q_x^2 + q_y^2} 19 17 20 18 Definition … … 28 26 29 27 I(q) = N\int_{0}^{\pi /2}\left[ \Delta \rho_t 30 \left( V_t f_t(q) - V_cf_c(q)\right) + \Delta \rho_cV_cf_c(q)31 \right]^2 S(q)\sin{\alpha d\alpha} + background28 \left( V_t f_t(q) - V_c f_c(q)\right) + \Delta \rho_c V_c f_c(q) 29 \right]^2 S(q)\sin{\alpha}\ d\alpha + \text{background} 32 30 33 31 where the contrast … … 35 33 .. math:: 36 34 37 \Delta \rho_i = \rho_i - \rho_ {solvent}38 39 and *N*is the number of discs per unit volume,40 $\alpha$ is the angle between the axis of the disc and *q*,35 \Delta \rho_i = \rho_i - \rho_\text{solvent} 36 37 and $N$ is the number of discs per unit volume, 38 $\alpha$ is the angle between the axis of the disc and $q$, 41 39 and $V_t$ and $V_c$ are the total volume and the core volume of 42 40 a single disc, respectively. … … 46 44 \left\langle f_{t}^2(q)\right\rangle_{\alpha} = 47 45 \int_{0}^{\pi/2}\left[ 48 \left(\frac{ sin(q(d+h)\cos{\alpha})}{q(d+h)\cos{\alpha}}\right)46 \left(\frac{\sin(q(d+h)\cos{\alpha})}{q(d+h)\cos{\alpha}}\right) 49 47 \left(\frac{2J_1(qR\sin{\alpha})}{qR\sin{\alpha}} \right) 50 \right]^2 \sin{\alpha d\alpha}48 \right]^2 \sin{\alpha}\ d\alpha 51 49 52 50 \left\langle f_{c}^2(q)\right\rangle_{\alpha} = 53 51 \int_{0}^{\pi/2}\left[ 54 \left(\frac{ sin(qh)\cos{\alpha})}{qh\cos{\alpha}}\right)55 \left(\frac{2J_1(qR\sin{\alpha})}{qR\sin{\alpha}} 56 \right]^2 \sin{\alpha d\alpha}57 58 where *d* = thickness of the layer (layer_thick),59 *2h* = core thickness (core_thick), and *R* = radius of the disc (radius).52 \left(\frac{\sin(qh)\cos{\alpha})}{qh\cos{\alpha}}\right) 53 \left(\frac{2J_1(qR\sin{\alpha})}{qR\sin{\alpha}}\right) 54 \right]^2 \sin{\alpha}\ d\alpha 55 56 where $d$ = thickness of the layer (*layer_thick*), 57 $2h$ = core thickness (*core_thick*), and $R$ = radius of the disc (*radius*). 60 58 61 59 .. math:: 62 60 63 61 S(q) = 1 + \frac{1}{2}\sum_{k=1}^n(n-k)\cos{(kDq\cos{\alpha})} 64 exp\left[ -k(q\cos{\alpha})^2\sigma_D/2\right]65 66 where *n* = the total number of the disc stacked (n_stacking),67 *D* = 2*(*d*+*h*)the next neighbor center-to-center distance (d-spacing),68 and $\sigma_D$ = the Gaussian standard deviation of the d-spacing ( sigma_d).62 \exp\left[ -k(q\cos{\alpha})^2\sigma_D/2\right] 63 64 where $n$ is the total number of the disc stacked (*n_stacking*), 65 $D = 2(d+h)$ is the next neighbor center-to-center distance (d-spacing), 66 and $\sigma_D$ = the Gaussian standard deviation of the d-spacing (*sigma_d*). 69 67 70 68 .. note:: 71 Each assmebly in the stack is layer/core/layer, so the spacing of the cores72 is core plus two layers. The 2nd virial coefficient of the cylinder is73 calculated based on the74 *radius* and *length*= *n_stacking* * (*core_thick* + 2 * *layer_thick*)69 Each assmebly in the stack is layer/core/layer, so the spacing of the 70 cores is core plus two layers. The 2nd virial coefficient of the cylinder 71 is calculated based on the *radius* and *length* 72 = *n_stacking* * (*core_thick* + 2 * *layer_thick*) 75 73 values, and used as the effective radius for $S(Q)$ when $P(Q) * S(Q)$ 76 74 is applied. … … 94 92 ---------- 95 93 96 A Guinier and G Fournet, *Small-Angle Scattering of X-Rays*, John Wiley and Sons, New York, 1955 94 A Guinier and G Fournet, *Small-Angle Scattering of X-Rays*, 95 John Wiley and Sons, New York, 1955 97 96 98 97 O Kratky and G Porod, *J. Colloid Science*, 4, (1949) 35 99 98 100 J S Higgins and H C Benoit, *Polymers and Neutron Scattering*, Clarendon, Oxford, 1994 99 J S Higgins and H C Benoit, *Polymers and Neutron Scattering*, 100 Clarendon, Oxford, 1994 101 101 102 102 **Author:** NIST IGOR/DANSE **on:** pre 2010
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