Refinement of hexamethylenetetramine based on diffractometer and imaging-plate data

1994 ◽  
Vol 27 (5) ◽  
pp. 722-726 ◽  
Author(s):  
J. Grochowski ◽  
P. Serda ◽  
K. S. Wilson ◽  
Z. Dauter
Keyword(s):  
Data Structure ◽  
Single Crystals ◽  
Imaging Plate ◽  
Data Sets ◽  
Two Dimensional ◽  
High Quality ◽  
Data Set ◽  
X Ray ◽  
Rotation Method ◽  
Comparable Accuracy

Two data sets were collected on single crystals of hexamethylenetetramine (urotropin) using a four-circle diffractometer with Cu Kα radiation and an imaging-plate two-dimensional detector with Mo Kα source using the rotation method. Both data sets extend to the same limit of sin θ/λ = 0.62 Å−1, corresponding to a resolution of 0.81 Å. Different processing protocols were employed for the two sets of data. Structure refinements carried out separately with each data set led to equivalent results of comparable accuracy. The imaging-plate scanner was able to provide X-ray data of high quality in a significantly shorter time than the diffractometer.

scholarly journals Use of Imaging Plates in X-Ray Analysis

1997 ◽  
Vol 29 (1-2) ◽  
pp. 89-101 ◽  
Author(s):  
M. Ermrich ◽  
F. Hahn ◽  
E. R. Wölfel
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Powder Diffraction ◽  
Polycrystalline Materials ◽  
Imaging Plate ◽  
Two Dimensional ◽  
X Ray ◽  
Working Principle ◽  
Imaging Plates

Two-dimensional detectors have opened a new area for the investigation of both single crystals and polycrystalline materials. The working principle of Imaging Plates is described. Some characteristics and the advantages of an Imaging Plate are discussed using the STOE Imaging Plate Diffraction System for different kinds of X-ray analysis: (i) single crystal diffractometry, (ii) powder diffraction and (iii) stress and texture investigations.

A double-radius Gandolfi X-ray camera for the generation of powder-like diffractograms of small single crystals, using an imaging plate detector

2002 ◽  
Vol 35 (1) ◽  
pp. 13-16 ◽  
Author(s):  
H. H. Otto ◽  
W. Hofmann ◽  
K. Schröder
Keyword(s):  
Single Crystals ◽  
Dynamic Imaging ◽  
Short Exposure ◽  
Imaging Plate ◽  
Data Sets ◽  
Short Exposure Time ◽  
X Ray ◽  
Diffraction Patterns ◽  
Non Destructive ◽  
Plate System

This is a report on the construction and the main features of an X-ray camera following the Debye–Scherrer geometry, combined with a sample mounting and rotation device for single crystals as first suggested by Gandolfi. Doubling of the camera radius and replacing of the wet-film technology by a highly dynamic imaging plate system allows well resolved digital diffraction patterns to be recorded within a short exposure time. Sophisticated calibration, correction and evaluation possibilities are supported by suitable software. Further optional improvements, such as the evacuation of the camera, the adaptation of totally reflecting collimators for an almost parallel primary X-ray beam and a built-in instead of an external imaging plate readout device, will further improve the resolution and peak to background ratio. The simple and versatile apparatus is indispensable for the fast and non-destructive identification of unique mineralogical or technical micro-samples in the form of single-crystal pieces. Initial representative data sets attest to the accuracy, efficiency and sensitivity of the method presented.

A batch-wise non-linear fitting and analysis tool for treating large X-ray diffraction data sets

2006 ◽  
Vol 39 (2) ◽  
pp. 262-266 ◽  
Author(s):  
R. J. Davies
Keyword(s):  
Diffraction Data ◽  
Operation Mode ◽  
Large Data ◽  
Scattering Data ◽  
Data Sets ◽  
Analysis Tool ◽  
Data Set ◽  
X Ray ◽  
Linear Fitting ◽  
Non Linear

Synchrotron sources offer high-brilliance X-ray beams which are ideal for spatially and time-resolved studies. Large amounts of wide- and small-angle X-ray scattering data can now be generated rapidly, for example, during routine scanning experiments. Consequently, the analysis of the large data sets produced has become a complex and pressing issue. Even relatively simple analyses become difficult when a single data set can contain many thousands of individual diffraction patterns. This article reports on a new software application for the automated analysis of scattering intensity profiles. It is capable of batch-processing thousands of individual data files without user intervention. Diffraction data can be fitted using a combination of background functions and non-linear peak functions. To compliment the batch-wise operation mode, the software includes several specialist algorithms to ensure that the results obtained are reliable. These include peak-tracking, artefact removal, function elimination and spread-estimate fitting. Furthermore, as well as non-linear fitting, the software can calculate integrated intensities and selected orientation parameters.

Crystal Structure of Eu2PdSi3

2003 ◽  
Vol 58 (10) ◽  
pp. 971-974 ◽  
Author(s):  
U. Ch. Rodewald ◽  
R.-D. Hoffmann ◽  
R. Pöttgen ◽  
E.V. Sampathkumaran
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Two Dimensional ◽  
Silica Tube ◽  
Variable Parameters ◽  
X Ray

Single crystals of Eu2PdSi3 were obtained from an arc-melted sample that was further annealed at 1020 K for seven days in a silica tube. The structure of Eu2PdSi3 was refined from single crystal X-ray diffractometer data: P6/mmm, a = 831.88(12), c = 435.88(9) pm, wR2 = 0.1175, 265 F2 values, and 13 variable parameters. It crystallizes with the U2RuSi3 structure, a superstructure of the AlB2 type. The palladium and silicon atoms form a planar two-dimensional [PdSi3] network. The two crystallographically different europium atoms have hexagonal prismatic coordinations Eu1Si12 and Eu2Pd4Si8. The Pd-Si and Si-Si distances within the [PdSi3] network are 244 and 236 pm, respectively.

Alternative Clustering

2017 ◽  
pp. 1-12 ◽  
Author(s):  
Avinash Navlani ◽  
V. B. Gupta
Keyword(s):  
Research Problem ◽  
Research Community ◽  
Data Sets ◽  
Complex Data ◽  
High Quality ◽  
Data Set ◽  
Alternative Clustering ◽  
Complex Data Sets ◽  
Data Objects ◽  
Community Clustering

In the last couple of decades, clustering has become a very crucial research problem in the data mining research community. Clustering refers to the partitioning of data objects such as records and documents into groups or clusters of similar characteristics. Clustering is unsupervised learning, because of unsupervised nature there is no unique solution for all problems. Most of the time complex data sets require explanation in multiple clustering sets. All the Traditional clustering approaches generate single clustering. There is more than one pattern in a dataset; each of patterns can be interesting in from different perspectives. Alternative clustering intends to find all unlike groupings of the data set such that each grouping has high quality and distinct from each other. This chapter gives you an overall view of alternative clustering; it's various approaches, related work, comparing with various confusing related terms like subspace, multi-view, and ensemble clustering, applications, issues, and challenges.

Two-dimensional (PEA)2PbBr4 perovskite single crystals for a high performance UV-detector

2019 ◽  
Vol 7 (6) ◽  
pp. 1584-1591 ◽  
Author(s):  
Yunxia Zhang ◽  
Yucheng Liu ◽  
Zhuo Xu ◽  
Haochen Ye ◽  
Qingxian Li ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
High Performance ◽  
Two Dimensional ◽  
Uv Detector ◽  
High Quality ◽  
Photo Response ◽  
Response Performance

A centimeter-sized high-quality two-dimensional (PEA)2PbBr4 single crystal was prepared, which exhibited superior UV photo-response performance.

A Ccomparison of sedigraph and pipette methods for soil particle-size analysis

Soil Research ◽  
1993 ◽  
Vol 31 (4) ◽  
pp. 407 ◽  
Author(s):  
GD Buchan ◽  
KS Grewal ◽  
JJ Claydon ◽  
RJ Mcpherson
Keyword(s):  
Particle Size ◽  
New Zealand ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Data Sets ◽  
Regression Equations ◽  
Total Iron Content ◽  
Data Set ◽  
X Ray ◽  
The Difference

The X-ray attenuation (Sedigraph) method for particle-size analysis is known to consistently estimate a finer size distribution than the pipette method. The objectives of this study were to compare the two methods, and to explore the reasons for their divergence. The methods are compared using two data sets from measurements made independently in two New Zealand laboratories, on two different sets of New Zealand soils, covering a range of textures and parent materials. The Sedigraph method gave systematically greater mass percentages at the four measurement diameters (20, 10, 5 and 2 �m). For one data set, the difference between clay (<2 �m) percentages from the two methods is shown to be positively correlated (R2 = 0.625) with total iron content of the sample, for all but one of the soils. This supports a novel hypothesis that the typically greater concentration of Fe (a strong X-ray absorber) in smaller size fractions is the major factor causing the difference. Regression equations are presented for converting the Sedigraph data to their pipette equivalents.

Charge Density of L-Alanyl-glycyl-L-alanine Based on X-Ray Data Collection Periods from 4 to 130 Hours

2007 ◽  
Vol 62 (5) ◽  
pp. 696-704 ◽  
Author(s):  
Diana Förster ◽  
Armin Wagner ◽  
Christian B. Hübschle ◽  
Carsten Paulmann ◽  
Peter Luger
Keyword(s):  
Synchrotron Radiation ◽  
Low Temperature ◽  
Charge Density ◽  
Data Sets ◽  
Data Set ◽  
X Ray ◽  
Atomic Properties ◽  
Multipole Refinement ◽  
Refinement Strategy ◽  
Experimental Charge Density

Abstract The charge density of the tripeptide L-alanyl-glycyl-L-alanine was determined from three X-ray data sets measured at different experimental setups and under different conditions. Two of the data sets were measured with synchrotron radiation (beamline F1 of Hasylab/DESY, Germany and beamline X10SA of SLS, Paul-Scherer-Institute, Switzerland) at temperatures around 100 K while a third data set was measured under home laboratory conditions (MoKα radiation) at a low temperature of 20 K. The multipole refinement strategy to derive the experimental charge density was the same in all cases, so that the obtained charge density properties could directly be compared. While the general analysis of the three data sets suggested a small preference for one of the synchrotron data sets (Hasylab F1), a comparison of topological and atomic properties gave in no case an indication for a preference of any of the three data sets. It follows that even the 4 h data set measured at the SLS performed equally well compared to the data sets of substantially longer exposure time.

In Situ Diffraction Studies: Thermal Decomposition of a Natural Plumbojarosite and the Development of Rietveld-Based Data Analysis Techniques

2010 ◽  
Vol 651 ◽  
pp. 37-64 ◽  
Author(s):  
Ian C. Madsen ◽  
Ian E. Grey ◽  
Stuart J. Mills
Keyword(s):  
Thermal Decomposition ◽  
Amorphous Material ◽  
Data Sets ◽  
X Ray Diffraction ◽  
Data Set ◽  
X Ray ◽  
Analysis Techniques ◽  
Path Lengths ◽  
Instrument Configuration

A study of the thermal decomposition sequence of a sample of natural arsenian plumbojarosite has been undertaken using in situ X-ray diffraction. The sample was heated to 900°C using an Anton-Paar heating stage fitted to an INEL CPS120 diffractometer. The data were analysed using a whole-pattern, Rietveld based approach for the extraction of quantitative phase abundances. The instrument configuration used required the development and application of algorithms to correct for aberrations in the (i) peak intensities due to differing path lengths of incident and diffracted beams in the sample and (ii) peak positions due to sample displacement. Details of the structural models used were refined at selected steps in the pattern and then fixed for subsequent analysis. The data sequence consists of some 110 individual data sets which were analysed sequentially with the output of each run forming the input for analysis of the next data set. The results of the analysis show a complex breakdown and recrystallisation sequence including the formation of a major amount of amorphous material after initial breakdown of the plumbojarosite.

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