Category Archives: Review
Comments on Deschamps, 2011 and A clarification on Guinier for Polydisperse systems
After browsing through a recent Journal of Applied Crystallography, I came across a paper by Deschamps. It indicates to me that there is a slight lack of information communication in some aspects of SAXS. Firstly, it mentions in the introduction that the advanced (Fourier-transform-based) SAXS analysis methods cannot “extract simultaneously the precipitate form factor and [...]
Book review: Ben Goldacre’s “Bad Science”
Hi all. Last week-end, while visiting friends nearby, a copy of the book “bad science” by Ben Goldacre was dropped in my lap. Having read the occasional post on his weblog (http://www.badscience.net/), I had already planned to get it. So I started reading the book with rather high expectations. (This copy, if I did not misunderstand [...]
Notes on Guinier
…well, his famous SAXS analysis method. This documentGuinier_short, copyright Brian Pauw gives a short description and review of the applicability of the Guinier method to polydisperse systems. It also shows, through analysis of simulated data, what q-range should be measured for the Guinier method to be valid. In short, the rule of qmax=1.3/Rg still holds, [...]
Read Ruland and more free reading (textbooks!)
Catching up to current affairs, I stumbled across this beauty. Now, I find this paper starts a little bit chaotic, but very quickly we come across some very useful equations indeed, and a link between the used equation for their analysis of phase transitions in fluids, and various other equations such as the Ornstein-Zernike structure [...]
Holiday reading, watching and writing.
Hi all, I found some interesting papers for you, and a talk. Let me start with the talk. It is a TED talk (naturally) concerning TED talks. This nice introspective talk is actually of interest for all of us as it gives a few pointers to the set-up of excellent (and terrible) talks, with a [...]
Bayesian Inverse Fourier Transforms
Although I cannot say I completely grasp the underlying theory, the Bayesian approach to the Inverse Fourier Transformation of (isotropic) small-angle scattering patterns certainly appeals to me. The idea is that the small-angle scattering pattern can be transformed (back) into real-space, resulting in either a distance distribution function p(r), a correlation function gamma(r) (=r^2 p(r) [...]
Particle size distribution: review of “Small-Angle X-ray and Neutron Scattering of Polydisperse Systems: Determination of the Scattering-Particle-Size Distribution”
The determination of the particle size distribution from small-angle scattering curves is usually achieved by assuming a certain statistical size distribution model (f.ex. a Schultz distribution, a Gaussian distribution or a log-normal distribution), and fitting this to the data using a non-linear least-squares optimisation method. Fitting multimodal distributions then implies the addition of multiple contributions, [...]
SASFIT software
The famous question of the uninitiated in small-angle scattering is: “Do you have a bit of software which will give me an answer from my data?”. After a lengthy explanation (coloured with some anecdotes) about why small-angle scattering is not a uniquely defined problem with an often unique answer such as wide-angle diffraction might be, the [...]
Book review: X-Ray Scattering of Soft Matter by Norbert Stribeck
I’ve borrowed a copy of the book “X-Ray Scattering of Soft Matter” by Norbert Stribeck (published by Springer) from one of my supervisors, and I’ve taken some time to browse through it. I must admit, I haven’t read it cover-to-cover, but have tried to use it as a reference book, just like ye olde “Small [...]
Interesting stuff
Ok, so I’ve been on holiday and haven’t updated the site in a while. My apologies for that.. I’ve been looking at some presentations from other groups and other organisations, and I see some very inspiring stuff there. Here’s what I’ve stumbled across in general: The TED talks are a collection of talks on a broad range of [...]