scholarly journals Diffraction pattern simulation of cellulose fibrils using distributed and quantized pair distances

2016 ◽  
Vol 49 (6) ◽  
pp. 2244-2248 ◽  
Author(s):  
Yan Zhang ◽  
Hideyo Inouye ◽  
Michael Crowley ◽  
Leiming Yu ◽  
David Kaeli ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
Computation Time ◽  
Atom Type ◽  
Data Set ◽  
X Ray ◽  
Short Period ◽  
Diffraction Patterns ◽  
Physical Treatments ◽  
The Impact ◽  
Pattern Simulation

Intensity simulation of X-ray scattering from large twisted cellulose molecular fibrils is important in understanding the impact of chemical or physical treatments on structural properties such as twisting or coiling. This paper describes a highly efficient method for the simulation of X-ray diffraction patterns from complex fibrils using atom-type-specific pair-distance quantization. Pair distances are sorted into arrays which are labelled by atom type. Histograms of pair distances in each array are computed and binned and the resulting population distributions are used to represent the whole pair-distance data set. These quantized pair-distance arrays are used with a modified and vectorized Debye formula to simulate diffraction patterns. This approach utilizes fewer pair distances in each iteration, and atomic scattering factors are moved outside the iteration since the arrays are labelled by atom type. This algorithm significantly reduces the computation time while maintaining the accuracy of diffraction pattern simulation, making possible the simulation of diffraction patterns from large twisted fibrils in a relatively short period of time, as is required for model testing and refinement.

scholarly journals The 3D structure of fibrous material is fully restorable from its X-ray diffraction pattern

IUCrJ ◽  
2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Hiroyuki Iwamoto
Keyword(s):  
Diffraction Pattern ◽  
Fibrous Material ◽  
3D Structure ◽  
Wide Field ◽  
Fibrous Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fiber Diffraction ◽  
Puzzle Solving ◽  
Diffraction Patterns

X-ray fiber diffraction is potentially a powerful technique to study the structure of fibrous materials, such as DNA and synthetic polymers. However, only rotationally averaged diffraction patterns can be recorded and it is difficult to correctly interpret them without the knowledge of esoteric diffraction theories. Here we demonstrate that, in principle, the non-rotationally averaged 3D structure of a fibrous material can be restored from its fiber diffraction pattern. The method is a simple puzzle-solving process and in ideal cases it does not require any prior knowledge about the structure, such as helical symmetry. We believe that the proposed method has a potential to transform the fiber diffraction to a 3D imaging technique, and will be useful for a wide field of life and materials sciences.

Simulation of the powder diffraction pattern of randomly restacked Ca2Nb3O10nanosheets

2009 ◽  
Vol 42 (6) ◽  
pp. 1062-1067 ◽  
Author(s):  
Mitsuko Onoda ◽  
Yasuo Ebina ◽  
Takayoshi Sasaki
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Matrix Method ◽  
Powder Pattern ◽  
X Ray ◽  
The Matrix ◽  
Pattern Simulation

From X-ray powder diffraction pattern features, layered KCa2Nb3O10·nH2O synthesized through flocculation of delaminated Ca2Nb3O10nanosheets with K ions appeared to be composed of randomly stacked nanosheets. Powder pattern simulation was conducted based on the matrix method using a random stacking model. When seven sheets were used as the coherent thickness, agreement in pattern fitting between the experimental and calculated intensities was satisfactory, and information about textures and atomic positions was obtained.

Powder X-Ray Data for Synthetic Anhydrous Sodium Zirconium Silicates

1987 ◽  
Vol 2 (3) ◽  
pp. 176-179 ◽  
Author(s):  
G. Wilson ◽  
F. P. Glasser
Keyword(s):  
Solid State ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
The Other ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Sodium Zirconium ◽  
Diffraction Patterns

AbstractA systematic survey of phase formation in the Na2O-ZrO2-SiO2 system has revealed inconsistencies in the number and identity of ternary phases, and of their X-ray powder data. The phases Na2ZrSiO5, Na4Zr2Si3O12, Na2ZrSi2O7 and Na2ZrSi4O11 were prepared by solid-state reaction and their experimental X-ray diffraction patterns measured. Calculated X-ray diffraction patterns were generated by computer, using published crystallographic data, and critically compared with the experimentally observed values. The unit-cell constants were redefined to a greater accuracy than the presently accepted values published in the Powder Diffraction File. Only Na4Zr2Si3O12 produced an X-ray diffraction pattern which agreed with that previously published; those from the other phases were significantly different in both the intensities and positions of the reflections. Data for synthetic Na2ZrSi4O11 identical to the mineral vlasovite are reported.

Study of diffraction data sets using factor analysis: a new technique for comparing mineralogical and geochemical data and rapid diagnostics of the mineral composition of large collections of rock samples

2019 ◽  
Vol 34 (S1) ◽  
pp. S59-S70 ◽  
Author(s):  
Ekaterina Fomina ◽  
Evgeniy Kozlov ◽  
Svetlana Ivashevskaja
Keyword(s):  
Geochemical Data ◽  
Chemical Compositions ◽  
Data Sets ◽  
Rapid Diagnostics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Short Period ◽  
Diffraction Patterns ◽  
A New Technique

This paper presents an example of comparing geochemical and mineralogical data by means of the statistical analysis of the X-ray diffraction patterns and the chemical compositions of bulk samples. The proposed methodology was tested on samples of metasomatic rocks from two geologically different objects. Its application allows us to mathematically identify all the main, secondary and some accessory minerals, to qualitatively estimate the contents of these minerals, as well as to assess their effect on the distribution of all petrogenic and investigated trace elements in a short period of time at the earliest stages of the research. We found that the interpretation of the results is significantly influenced by the number of samples studied and the quality of diffractograms.

The Hinckley index for kaolinites

Clay Minerals ◽  
1988 ◽  
Vol 23 (3) ◽  
pp. 249-260 ◽  
Author(s):  
A. Plançon ◽  
R. F. Giese ◽  
R. Snyder
Keyword(s):  
Diffraction Pattern ◽  
Defect Structure ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Linear Fashion ◽  
Non Linear ◽  
Diffraction Patterns ◽  
Good Agreement

AbstractThe (02,11) X-ray diffraction band from a low-defect kaolinite from Cornwall (Hinckley index HI = 1·22) was examined to determine the defect structure. No combination of interlayer translations and admixing of dickite layers accurately modelled the observed diffraction pattern. Calculated diffraction patterns which gave a good agreement with the shape, position, and intensity of the observed peaks, uniformly had inter-peak intensities which were too weak. By treating the kaolinite as a mixture of low-defect (HI = 1·76) and moderate-defect (HI = 0·29) kaolinites, the agreement between the observed and calculated patterns was improved substantially. The existence of a mixture of two kaolinites was also found for a number of low-defect samples (HI > 0·4) from Georgia and Cornwall, and may be of even wider occurrence. The HI, which is very sensitive to the inner-peak intensities, does not estimate the types or abundances of various structural defects (the classical “crystallinity”), but is related directly, in a non-linear fashion, to the proportions of the two kinds of kaolinite which are present in the sample.

Low-Angle X-Ray Diffraction and Electron-Microscope Studies of Isolated Cell Membranes

1966 ◽  
Vol 1 (3) ◽  
pp. 287-296
Author(s):  
J. B. FINEAN ◽  
R. COLEMAN ◽  
W. G. GREEN ◽  
A. R. LIMBRICK
Keyword(s):  
Diffraction Pattern ◽  
Close Packing ◽  
Hexagonal Structure ◽  
Erythrocyte Membranes ◽  
Multiphase System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Guinea Pig Brain ◽  
Isolated Cell

A sequence of low-angle X-ray diffraction patterns obtained during the controlled drying of a preparation of rat erythrocyte ghosts has been interpreted with the aid of corresponding electron micrographs and of a parallel study of myelin isolated from guinea-pig brain. A diffraction pattern that persists down to a level of 10-20% hydration of the sample is believed to arise from the close packing of native erythrocyte membranes. Each membrane is about 100 Å thick and it is suggested that it consists of a predominantly continuous bimolecular layer of lipid, with non-lipid components associated with both surfaces. Further changes in diffraction pattern which accompany continued drying could be interpreted either as a change from a lamellar to a hexagonal structure or as the formation of a multiphase system. Evidence is put forward to support the latter interpretation.

A New Position Sensitive Detector for X-Ray Diffractometry

1992 ◽  
Vol 36 ◽  
pp. 617-622
Author(s):  
J. L. Radtke ◽  
D. W. Beard
Keyword(s):  
Position Sensitive Detector ◽  
Data Sets ◽  
X Rays ◽  
Sensitive Detector ◽  
Detector Performance ◽  
X Ray ◽  
Time Quantum ◽  
Position Sensitive ◽  
Diffraction Patterns ◽  
The Impact

AbstractPosition sensitive detectors provide efficient X-ray detection over large solid angles; this capability has revolutionized X-ray diffractometry by reducing data collection time. This paper describes testing of a new single-axis position sensitive detector designed to locate 0.6-2 Angstrom X-rays. Dead time, quantum efficiency, energy resolution, and spatial resolution were measured. Standard powder diffraction patterns were observed with the detector, and data sets are presented. The impact of detector performance parameters on diffraction experiments is discussed.

X-ray powder diffraction studies of fibrillar zinc trimolybdates ZnMo3O10·nH2O (n=3.75,5,10)

1999 ◽  
Vol 14 (4) ◽  
pp. 276-279
Author(s):  
Wiesław Łasocha ◽  
Wiesław Surga ◽  
Alicja Rafalska-Łasocha
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Lattice Parameters ◽  
Fiber Axis ◽  
Powder Diffraction Data ◽  
Parallel Fibers ◽  
X Ray ◽  
Space Groups ◽  
Diffraction Patterns

The X-ray powder diffraction data of polycrystalline fibrillar zinc trimolybdates ZnMo3O10·3.75H2O, ZnMo3O10·5H2O, and ZnMo3O10·10H2O, are reported. An uncommon diffraction pattern was recorded in the case of the “wet fibers” of ZnMo3O10·10H2O, which could be indexed assuming a model of parallel fibers with translation disorder along the fiber axis. The powder diffraction patterns, lattice parameters, space groups, and other data describing these compounds are presented in this paper.© 1999 International Centre for Diffraction Data.

Sign in / Sign up

Export Citation Format

Share Document