Two-Dimensional Diffraction Pattern by a Silk Cloth

2020 ◽  
Vol 58 (1) ◽  
pp. 46-47
Author(s):  
Ravi Kant Avvari
Keyword(s):  
Diffraction Pattern ◽  
Two Dimensional ◽  
Silk Cloth

scholarly journals Crystallinity fitting using cellulose crystallite models

2014 ◽  
Vol 70 (a1) ◽  
pp. C1135-C1135
Author(s):  
Patrik Ahvenainen ◽  
Ritva Serimaa
Keyword(s):  
Diffraction Pattern ◽  
Cell Structure ◽  
Unit Cell ◽  
Scattering Data ◽  
Crystalline Cellulose ◽  
Two Dimensional ◽  
Cellulose Crystallite ◽  
Cellulose Iβ ◽  
Diffraction Peaks ◽  
Unit Cell Structure

Cellulose is the most abundant biopolymer on Earth and hence it has enormous potential as a source of renewable energy. The nanoscale properties of cellulose are also import for the wood and papermaking industries. The atomic level structure of naturally occurring cellulose Iβ allomorph is well known [1] and this atomistic model is employed in this study for the cellulose unit cell structure. The cellulose crystallinity cannot be measured directly with scattering methods, but the crystallinity of the sample can be estimated by fitting models of crystalline and amorphous contributions to the sample intensity profile. The crystallinity fitting can be enhanced by improving the cellulose fitting model or the amorphous model. We focus on the cellulose crystallite model. The nanoscale level organization of crystalline cellulose in different plant materials is less well established that the unit cell structure of cellulose Iβ. Information on the texture of the sample is obtained efficiently by measuring the sample with a two-dimensional detector. The two-dimensional diffraction pattern can be used to obtain a wealth of information in one measurement, including the crystallite size, crystallite orientation and the crystallinity of the sample. The small size of cellulose crystallites in the wood cell wall limits the information obtainable from the diffraction pattern as the diffraction peaks widen and overlap. The overlapping of certain diffraction peaks can be studied at least qualitatively by computing the diffraction patterns from crystallite models of varying dimensions. Different models for cellulose crystallite have been suggested in the literature, such as the 36 chain model [2]. We investigate how the crystallinity fitting is influenced by the selected cellulose crystallite model and evaluate the suitability of different models to experimental X-ray scattering data of plant material, wood and highly crystalline cellulose.

An optical method of studying the diffraction from imperfect crystals I. Modulated structures

1957 ◽  
Vol 239 (1217) ◽  
pp. 184-191 ◽  
Keyword(s):  
Diffraction Pattern ◽  
Optical Method ◽  
Photographic Plate ◽  
Flat Glass ◽  
Lattice Parameter ◽  
Optical Diffraction ◽  
Age Hardening ◽  
Two Dimensional ◽  
Structure Amplitude ◽  
Modulated Structures

The correspondence between the X-ray diffraction pattern of a crystal and the optical diffraction pattern of a two-dimensional grating has been used to determine the nature of the diffraction from imperfect crystals. A two-dimensional grating representing the structure of the imperfect crystal is prepared on a very fine-grained photographic plate by a technique which gives an error of less than 1 μ in the positions of the elements of the grating. The grating is placed in a bath of cedar-wood oil between optically flat glass plates, and its Fraunhofer diffraction pattern is observed in a modified Lipson diffractometer. Illustrations are given of the application of the optical method to the study of the diffraction from modulated structures, such as the alloy Cu 4 FeNi 3 with a periodic variation of lattice parameter, and the age-hardening aluminium-copper alloy with a variation of both lattice parameter and structure amplitude.

scholarly journals Comment on ‘Multilayered Stable 2D Nano-Sheets of Ti2NTx MXene: Synthesis, Characterization, and Anticancer Activity’

2020 ◽  
Author(s):  
Yitong Guo ◽  
Qianku Hu ◽  
Libo Wang ◽  
Aiguo Zhou
Keyword(s):  
Anticancer Activity ◽  
Diffraction Pattern ◽  
Hydrofluoric Acid ◽  
Recent Article ◽  
Room Temperature ◽  
Max Phase ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray

<p>A recent article entitled “Multilayered stable 2D nano-sheets of Ti<sub>2</sub>NT<sub>x</sub> MXene: synthesis, characterization, and anticancer activity” published in this journal, claimed that two-dimensional Ti<sub>2</sub>NT<sub>x</sub> MXene could be synthesized by selectively etching Ti<sub>2</sub>AlN in concentrated hydrofluoric acid at room temperature. However, the X-ray diffraction pattern of Ti<sub>2</sub>NT<sub>x</sub> MXene reported in that paper is completely different with those of other MXenes. In this comment, it is argued that the samples synthesized in that paper were NOT Ti<sub>2</sub>NT<sub>x</sub> MXene at all. Although carbide MXenes can be made by selectively etching A layers from MAX phase, it is very difficult or impossible to make nitride MXenes (Ti<sub>2</sub>NT<sub>x</sub>) by the same way.</p>

Algorithms of Two-Dimensional X-Ray Diffraction

MRS Advances ◽  
2016 ◽  
Vol 1 (26) ◽  
pp. 1921-1927
Author(s):  
Bob B. He
Keyword(s):  
Diffraction Pattern ◽  
Intensity Distribution ◽  
Structure Refinement ◽  
Azimuthal Angle ◽  
Bragg Angle ◽  
Phase Identification ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Diffraction Vector ◽  
X Ray

ABSTRACTX-ray diffraction pattern collected with two-dimensional detector contains the scattering intensity distribution as a function of two orthogonal angles. One is the Bragg angle 2θ and the other is the azimuthal angle about the incident x-ray beam, denoted by γ. A 2D diffraction pattern can be integrated to a conventional diffraction pattern and evaluated by most exiting software and algorithms for conventional applications, such as, phase identification, structure refinement and 2θ-profile analysis. However, the materials structure information associated to the intensity distribution along γ direction is lost through the integration. The diffraction vector approach has been approved to be the genuine theory in 2D data analysis. The unit diffraction vector used for 2D analysis is a function of both 2θ and γ. The unit diffraction vector for all the pixels in the 2D pattern can be expressed either in the laboratory coordinates or in the sample coordinates. The vector components can then be used to derive fundamental equations for many applications, including stress, texture, crystal orientation and crystal size evaluation.

Recent Advances in Texture Measurement Using Two-Dimensional Detector

2011 ◽  
Vol 702-703 ◽  
pp. 507-510
Author(s):  
Bob B. He
Keyword(s):  
Diffraction Pattern ◽  
Texture Analysis ◽  
Intensity Variation ◽  
High Sensitivity ◽  
Low Noise ◽  
Sample Space ◽  
Two Dimensional ◽  
High Count ◽  
Texture Measurement ◽  
Diffraction Patterns

The two most important advances in two-dimensional x-ray diffraction (XRD2) are area detectors for collecting 2D diffraction patterns and algorithms in analyzing 2D diffraction patterns. The VÅNTEC-500 area detector represents the innovation in detector technology. The combination of its large active area, high sensitivity, high count rate, high resolution and low noise, makes it the technology of choice for many applications, including texture analysis. A 2D diffraction pattern contains information in a large solid angle which can be described by the diffraction intensity distribution in both 2θ and g directions. The texture information appears in a 2D diffraction pattern as intensity variation in g direction. The intensity variation represents the orientation distribution of the crystallites in a polycrystalline material. The diffraction vector orientation regarding to the sample orientation can be obtained by vector transformation from the laboratory space to the sample space. The fundamental equations for texture analysis are derived from the unit vector expression in the sample space.

scholarly journals Comment on ‘Multilayered Stable 2D Nano-Sheets of Ti2NTx MXene: Synthesis, Characterization, and Anticancer Activity’

2020 ◽  
Author(s):  
Yitong Guo ◽  
Qianku Hu ◽  
Libo Wang ◽  
Aiguo Zhou
Keyword(s):  
Anticancer Activity ◽  
Diffraction Pattern ◽  
Hydrofluoric Acid ◽  
Recent Article ◽  
Room Temperature ◽  
Max Phase ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray

<p>A recent article entitled “Multilayered stable 2D nano-sheets of Ti<sub>2</sub>NT<sub>x</sub> MXene: synthesis, characterization, and anticancer activity” published in this journal, claimed that two-dimensional Ti<sub>2</sub>NT<sub>x</sub> MXene could be synthesized by selectively etching Ti<sub>2</sub>AlN in concentrated hydrofluoric acid at room temperature. However, the X-ray diffraction pattern of Ti<sub>2</sub>NT<sub>x</sub> MXene reported in that paper is completely different with those of other MXenes. In this comment, it is argued that the samples synthesized in that paper were NOT Ti<sub>2</sub>NT<sub>x</sub> MXene at all. Although carbide MXenes can be made by selectively etching A layers from MAX phase, it is very difficult or impossible to make nitride MXenes (Ti<sub>2</sub>NT<sub>x</sub>) by the same way.</p>

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