Dear Rietvelders,
I am little confused about the term "Anomalous scattering factor" and
"Dispersion coefficients".
"Anomalous scattering factor" can be found here
http://skuld.bmsc.washington.edu/scatter/AS_form.html
"Dispersion coefficients" can be found here
http://www.cxro.lbl.gov/optical_c
ited Kingdom
+44 (0) 20 7679 1004 (laboratory)
j.k.cockcr...@ucl.ac.uk or jeremyk...@gmail.com
http://img.chem.ucl.ac.uk/www/cockcroft/homepage.htm
***
On 11 June 2015 at 15:33, iangie wrote:
Dear Rietvelders,
I am little confused abo
Hi Apu,
Your peak looks super-Lorentzian. Super-Lorentzian peak can be due to bimodal
distribution (Young, R. A. & Sakthivel, A. (1988). J. Appl. Crystallogr.21,
416-425.) or wide Lognormal distribution (Popa, N. C. & Balzar, D. (2002). J.
Appl. Crystallogr.35, 338–346.).
In the latter case, P
Dear Alan,
I have a few patterns of samples in 0.3mm Boron-Rich Glass capillaries but
collected in Debye-Scherrer mode.
What does "Capillary Specimen data collected in reflection mode" mean, high
angle peaks only?
Cheers!
--
Yours Sincerely,
Dr. Xiaodong(Tony) Wang
XRD Application Scientist
Dear Friends,
Below macro was already developed in 10th TOPAS user meeting @ Adelaide:
TOPAS syntax code for the modified intensity correction and flat specimen
asymmetry peak shape convolution
‘Variable_Divergence_Shape_Correction: v = footprint (EDFL); keh = knife edge
height
macro Vari
Echo
reducing tube power just reducing intensity which reduces your peak height
together with the background level. It won't help on the peak to background
ratio.
What you need to improve is the beam path. WhenI was checking the low angle
beam path, I measured the stage/goniometer dimensio
Dear Frantisek,
>I have tried the 0.26 and 0.14° FDS, however a large "beam overflow" has
>occurred. Moreover, the intensities of diffractions at higher angles are very
>low in comparison to the data collected with ADS slits.
[TW] At θ=1° , 0.26 and 0.14° FDS coresponding to ~39 and ~74 mm foot
Hi Jools,
1) Press the icon "Show single peak curves" to have all the calculated peak
profile displayed.
2) Right click the range "*.raw", and choose "save if displayed Yobs, Ycalc,
Diff, Phases, Bkg" from the right-click menu.
--
Yours Sincerely,
Dr. Tony Wang
At 2016-12-12 05:55:09, "Jul
Hi Nelson,
The X-ray atomic form factor has a propotion which changes with wavelegnth.
So do not apply the relative intensities in Cu radiation in the NIST
Certificate on your mearement in Co radiation.
Even you simulate a corundum pattern from a Rietveld code under Co radiation,
it will be dif
Dear David,
Why not upgrade your EVA, if you are talking about DIFFRAC.EVA.
If I am still correct, you should be able to open the latest version of
DIFFRAC.EVA using lower level license.
You will not see the new functions specfic to higher level license, but will
benefit from bug fixes since
Hi Nelson,
The very fact you see these two options means the software you are using does
not provide deserved separated treatments for converting Ka1 and Ka2 lines.
It is, most likely, simply applying Bragg's law to convert the 2theta axis
only, which assumes Ka2 lines are from separate d-spaci
Dear Rietvelders,
Queensland University of Technology is seeking candidates for its recent
openings of X-ray Analysis Coordinator position.
The successful candidate needs to work with experienced XRD/XRF analysis team
and internal/external customers.
Please view details on
https://qut.nga
Dear Rietvelder,
I hope you are doing well.
It is generally acknolwdged that Rietveld refinement should be performed on raw
data, without any data processing.
One of our diffractometer/PSD scans data at its minimal step size (users can
see that the step size during scan is much smaller than w
ing a fit
And then rebinning with various slit widths and then fitting
And then comparing parameters errors and parameter values for all the
refinements should shine light on the area.
I don’t know where but I feeling is that there should be papers on this.
Cheers
Alan
From: rietv
some different step times) to collect a range
of different intensities. The standard deviation of the "raw" counts (not raw
CPS) should approximately the square root of the number of counts. If it is
different, then something squirrelly is going on.
Matthew
On Fri, 27 Sep 2019 at 13:46,
Hi Shay,
>Is it possible that I observed changes of 10-5A+/-10-6A in d-space?
Are you sure you are asking the precision of d-spacing not of the refined
lattice parameters from whole pattern?
The precision of d-spacing depends on which 2Theta angle are you talking about,
according to the deriv
Dear Matthew,
I tried your data and get ~-1% amorphous. My .pro is in below link.
https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0
I normally do not refine Beq, which I believe gives biggest source of error in
QPA...
Cheers!
--
Dr. Xiaodong (Tony) Wang
Senior Research Infrastructu
rption edge correction; I always
>> forget which parameter is which thing and have to rederive my understanding
>> of
>> it everytime...
>>
>>
>> Thanks
>>
>> Matthew
>>
>> On Wed, 13 Apr 2022 at 13:58, iangie > <mailto:ian...@1
Dear Mathew,
Understood these values are from the SRM certificate.
My .pro of the data suggests ~92% alpha, 3% beta, and ~5% Amorphous:
https://www.dropbox.com/s/r2l4y0iq7d4baj7/ROW.pro?dl=0
Can you reproduce those values on the certificate?
Cheers!
--
Dr. Xiaodong (Tony) Wang
Senior Research
can get
> up
> to 8.5 wt% amorphous.
>
> In all of this, corundum is staying as charged atoms, with Al and O beqs fixed
> at 0.334 and 0.278.
>
> I'll have to have a go at applying the absorption edge correction; I always
> forget which parameter is which thing and have to reder
: tony.w...@qut.edu.au | Web: www.qut.edu.au/ife/carf
在 2022-04-30 11:53:46，"Matthew Rowles" 写道：
Hi Tony
I can't reproduce the certificate values. This is the entire point of my
question.
Matthew
On Fri, 29 Apr 2022, 08:31 iangie, wrote:
Dear Mathew,
Understood t
Hi Shay,
Every company will answer that their product is the best.
I suggest you send typical samples you are going to run in the future, to each
potential company and compare the demo data quality.
In your contract state that "demo data need be resonably reproducible before
acceptance", so th
Dear Prof. Chateigner,
I might need to update my knowledge.
Do we need to consider texture effect for powder samples?
Best Regards!
--
Dr. Xiaodong (Tony) Wang
Senior Research Infrastructure Specialist (XRD)
Central Analytical Research Facility (CARF) | Queensland University of
Technology
Dear Matthew,
I have done several QPA for pharmaceutical formulars for QUT Health. One
example is: https://doi.org/10.1016/j.ijpharm.2020.119684
They were all measured using Debye-Scherrer geometry, becasue too much
penetration/absorption error in Bragg-Brentano.
Many APIs have particle si
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