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Topic: X-ray diffraction

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X-ray crystallography - Wikipedia, the free encyclopedia X-ray diffraction is commonly carried out using single crystals of a material, but if these are not available, microcrystalline powdered samples may also be used, although this requires different equipment and is much less straightforward. X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of X-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. X-ray diffraction finds frequent use in materials science because sample preparation is relatively easy, and the test itself is often rapid and non-destructive. en.wikipedia.org /wiki/X-ray_diffraction   (720 words)

MSN Encarta - Search Results - X-ray diffraction X-Ray Diffraction, method of determining atomic and molecular structures by measuring patterns of scattered X rays after they pass through a... X Ray : Properties of X Rays : X-Ray Diffraction MSN Encarta - Search Results - X-ray diffraction encarta.msn.com /X-ray+diffraction.html   (143 words)

X-ray diffraction --  Encyclopædia Britannica Diffraction takes place with sound; with electromagnetic radiation, such as light, X-rays, and gamma rays; and with very small moving particles such as atoms, neutrons, and electrons, which show wavelike properties. In this technique X rays are allowed to strike the crystal; the X rays are diffracted by the crystal and impinge on a photographic plate, forming a pattern of spots. When a thin, pencil-like beam of X rays is allowed to impinge on a crystal, those of certain wavelengths will be oriented at just the proper angle to a group of atomic planes so that they will combine in phase to... www.britannica.com /eb/article?eu=79745   (902 words)

NREL: Measurements and Characterization - X-Ray Diffraction X-ray diffraction is a versatile, non-destructive technique used for identifying the crystalline phases present in solid materials and powders and for analyzing structural properties (such as stress, grain size, phase composition, crystal orientation, and defects) of the phases. This XRD is used for identifying the crystalline phases in solid materials and powders. By varying the angle of incidence, a diffraction pattern emerges that is characteristic of the sample. www.nrel.gov /measurements/xray.html   (363 words)

Monitoring the Solidification of Single-Crystal Castings Using High-Energy X-Ray Diffraction The measured gray level of a transmission diffraction spot from a typical experiment where the x-ray beam was scanned vertically in the casting is plotted in Figure 11 along with a model (Lever) prediction of the fraction of solid versus temperature for N5 alloy. The XRD intensity of an unpolarized x-ray beam from a small crystal when the Bragg condition is satisfied may be calculated from the kinematical theory of diffraction. The x-ray method was capable of sensing changes in the physical state of the casting (liquid or solid) and measuring the fraction of solid in the region of dendritic solidification. www.tms.org /pubs/journals/JOM/9907/Fitting/Fitting-9907.html   (6736 words)

X-Ray Diffraction Diffraction of an x-ray beam striking a crystal occurs because the It is these reinforced (diffracted) x-rays that produce the characteristic x-ray diffraction patterns that used for mineral ID. The diffracted x-rays are detected electronically and recorded on a inked strip chart. www.csam.montclair.edu /earth/eesweb/gorring/geos443/443notes/xray.html   (771 words)

Re: X-ray diffraction X ray diffraction means X rays could be diffracted by passing them through crystals. X -ray diffraction has two types which are powder crystal and single crystal. In the other words, X rays will be most efficiently diffracted by a crystal when the X-ray wavelength and distance between the crystal atoms are known. vclass.mtsac.edu:920 /chem1a/_disc11/00000064.htm   (208 words)

X-ray diffraction - Hutchinson encyclopedia article about X-ray diffraction X-rays directed at such substances spread out as they pass through the crystals owing to diffraction (the slight spreading of waves around the edge of an opaque object) of the rays around the atoms. Method of studying the atomic and molecular structure of crystalline substances by using X-rays. By using measurements of the position and intensity of the diffracted waves, it is possible to calculate the shape and size of the atoms in the crystal. encyclopedia.farlex.com /X-ray%20diffraction   (161 words)

CrystalDiffract: Introduction This includes the ability to visualize multiple diffraction patterns in the same window, simulate multi-phase mixtures, time-of-flight and energy-dispersive diffraction, compare observed experimental data with simulated data, and much more... You can also edit site occupancies - perhaps to investigate the effects of structural disorder on a diffraction pattern - and even exclude selected sites from the diffraction calculation. Diffraction patterns can be displayed as traditional greyscale "films", or as diffractometer traces (graphs of intensity versus two-theta, d-spacing, 1/d, time-of-flight or energy). www.crystalmaker.co.uk /crystaldiffract   (404 words)

research center ocean margins - X-ray diffraction XRD measurements are frequently used in paleoceanograhy to distinquish terrigenous and marine components of the sediment and use single or groups of minerals as tracer of riverine input. More information on research and expertise of the people at our XRD laboratory can by found on the webpages of the geoscience department. Mineralogical investigations can also be utilized for research on diagenesis or authigenic materials at mid ocean ridges, as well as redox potentials of the sediment. www.rcom-bremen.de /English/X-ray_diffraction.html?Mode=91   (152 words)

X- Ray Diffraction X- ray powder diffraction is a useful technique for qualitative analysis and for the determination of major and minor phases. In X-ray diffraction analysis, X-rays are used to determine crystalline compound in a given sample. The analysis is based on that X-ray will be diffracted by crystal planed and minerals can be identified by measuring this diffraction at different angles. www.squ.edu.om /sci/Earth/facilities/xrd.html   (134 words)

X-RAY DIFFRACTION - Definition [n] the scattering of X rays by the atoms of a crystal; the diffraction pattern shows structure of the crystal www.hyperdictionary.com /dictionary/X-ray+diffraction   (20 words)

xray.doc This is a standard technique in materials science; typically one knows the wavelength of the x rays and uses the diffraction pattern to figure out the location and orientation of the atoms in the crystal. “X rays” are electromagnetic radiation with very short wavelength, on the order of 0.1nm (to be compared with visible light, with a wavelength of the order of 500nm). This wavelength is comparable to the spacing of atoms in a solid, which means that it is possible to use a crystal to diffract x rays. www.sussex.ac.uk /physics/teaching/bes/xray.doc   (428 words)

Rigor-Force Producing Cross-Bridges in Skeletal Muscle Fibers Activated by a Substoichiometric Amount of ATP -- Yamada et al. 85 (3): 1741 -- Biophysical Journal X-ray diffraction evidence for the extensibility of actin and myosin filaments during muscle contraction. X-ray diffraction studies on the structural changes of rigor muscles induced by binding of phosphate analogs in the presence of MgADP. X-ray diffraction measurements of the extensibility of actin and myosin filaments in contracting muscle. www.biophysj.org /cgi/content/full/85/3/1741   (7222 words)

Elements of X-Ray Diffraction X- Ray diffraction is a tool for the investigation of the fine structure of matter. This technique had its beginning in von Laue's' discovery in 1912 that crystals diffract x-rays, the manner of the diffraction revealing the structure of the crystal. The purpose of this book is to acquaint the reader who has no previous knowledge of the subject with the theory of x-ray diffraction, the experimental methods involved, and the main applications. www.allbookstores.com /book/0201011743   (107 words)

low angle X ray diffraction analysis study of matter by analysis of the diffraction of X rays with diffraction angles smaller than a few degrees. crisp.cit.nih.gov /Thesaurus/00004726.htm   (19 words)

X-Ray Diffraction Simulator The X-Ray Diffraction Simulator is a program developed at Carnegie Mellon using the cT programming language as an aid to teaching undergraduate courses involving crystallography. It is possible to specify one of the ordinary wavelengths of x-rays used in practice to be used in calculating the diffraction pattern. Finally, the program will calculate the diffraction pattern produced by the unit cell. neon.mems.cmu.edu /degraef/xray   (271 words)

The British Museum, Department of Scientific Research: X-ray diffraction X-ray diffraction analysis is particularly useful in the study of museum objects because it is almost non-destructive. The British Museum, Department of Scientific Research: X-ray diffraction Unlike techniques such as X-ray fluorescence (XRF), atomic absorption spectrometry (AAS), inductively-coupled plasma/mass spectrometry (ICP/MS) and other methods of chemical analysis that provide information on elemental composition, XRD allows a particular mineral to be identified. www.thebritishmuseum.ac.uk /science/techniques/sr-tech-xrd.html   (235 words)

Bruker AXS - X-ray diffraction X-ray diffraction is the analytical technique which links the nanometer length scale with the real world. A wide variety of samples of micrometer up to meter size can be investigated by x-ray diffraction or x-ray scattering instrumentation. X-rays having the same dimension as intercrystalline spacings are the ideal probe to non-destructively investigate fluid or solid matter. www.x-ray-diffraction.net /index.html   (73 words)

MS&E 448: Crystallography and X-Ray Diffraction The theory of diffraction of X-rays, including the determination of both the direction and intensities of diffracted beams; calculation of the structure factor and using it in diffraction problems. The reciprocal lattice, including an introduction to the concept of reciprocal space and the reciprocal lattice and the expression of diffraction phenomena in terms of the reciprocal lattice. Introduce concepts regarding the physics of diffraction so that the students will be able to understand the strengths and weaknesses of diffraction methods as a materials characterization technique. www.engr.wisc.edu /mse/courses/mse448.html   (474 words)

X Ray Diffraction Procedures For Polycrystalline and Amorphous Materials 2nd Edition Even today, over 25 years after the release of the lasest edition, "X-ray Diffraction Procedures" is because of it's thoroughness, attention to detail, number and depth of subjects dealt with still a must for anybody working with X-Ray Diffraction. Klug & Alexanders book on X-ray diffraction has since it's release, of the first edition in 1954, been and still is the ultimate book on X-ray diffraction procedures. X Ray Diffraction Procedures For Polycrystalline and Amorphous Materials 2nd Edition www.hallscience.com /store/books_0471493694_X-Ray-Diffraction-Procedures-For-Polycrystalline-and-Amorphous-Materials-2nd-Edition.html   (179 words)

X-ray Diffraction XRD data are sensitive to as many as 35 different factors. The XRD powder method relies on principle that all possible crystallographic orientations are presented to the beam. Diffraction scattering from materials other than the specimen including soller slits, specimen binder, sample mount and air. www.gly.uga.edu /schroeder/geol3010/XRD.html   (2333 words)

X-Ray Diffraction X-ray diffraction is coherent elastic scattering of x-rays by atoms or ions in a crystal. Because the wavelength of photons with energy of order 10 KeV is a little smaller than the spacing of atoms in solids, a crystal will act as a sort of diffraction grating for x-ray. For certain alignments of the crystal and detector relative to the x-ray beam, all atoms in the crystal scatter in phase*. landau1.phys.virginia.edu /classes/318.gbh.spring05/xray/xray.html   (1031 words)

ipedia.com: Crystallography Article X-ray crystallography is the primary method for determining the molecular conformations of proteins and other biological macromolecules (the double-helical structure of DNA, for example, was deduced from X-ray diffraction patterns). This level of order can be sufficient to deduce the structure of simple molecules, or to determine the coarse features of more complicated molecules (the double-helical structure of DNA, for example, was deduced from an X-ray diffraction pattern that had been generated by a fibrous sample). The diffraction patterns from protein crystals can be very complex, and their analysis requires computers and sophisticated techniques. www.ipedia.com /crystallography.html   (869 words)

Bragg's Law and Diffraction Although Bragg's law was used to explain the interference pattern of X-rays scattered by crystals, diffraction has been developed to study the structure of all states of matter with any beam, e.g., ions, electrons, neutrons, and protons, with a wavelength similar to the distance between the atomic or molecular structures of interest. This observation is an example of X-ray wave interference (Roentgenstrahlinterferenzen), commonly known as X-ray diffraction (XRD), and was direct evidence for the periodic atomic structure of crystals postulated for several centuries. The rays of the incident beam are always in phase and parallel up to the point at which the top beam strikes the top layer at atom z (Fig. www.eserc.stonybrook.edu /ProjectJava/Bragg   (847 words)

TS X-ray Diffraction After the discovery of the diffraction of X rays by crystals in 1912, Bragg and his son, William L., derived Bragg's law, which relates the wavelength of X rays to the glancing angle of reflection. None of these would be possible if Watson and Crick had not deduced the structure of DNA using X-ray diffraction. After Wilhelm Roentgen discovered X rays in 1895, Bragg began a lifelong investigation of the nature of radiation, principally X rays but also alpha and beta particles and gamma rays. ep.llnl.gov /bep/science/12/tXray.html   (1139 words)

X – Ray powder diffraction study of leucite crystallisation X – Ray powder diffraction study of leucite crystallisation Crystallisation of leucite was monitored at 800, 900 and 1000°C using X-ray powder diffraction analysis. At high temperatures the stable form of leucite is cubic (high leucite), and as it cools below a temperature of about 630°C there is a displacement phase transformation to tetragonal (low leucite). www.xray.cz /epdic/abstracts/449.htm   (271 words)

X ray crystallization of recombinant membrane proximal structural domain of human GABAA receptor α1 subunit overexpressed in Escherichia coli The recombinant protein crystals appeared, as octahedron in shape, and quality of the crystal is suitable for high-resolution structural data collection under preliminary X ray diffraction studies. X ray crystallization of recombinant membrane proximal structural domain of human GABAA receptor α1 subunit overexpressed in Escherichia coli Hong Xue1,2,ManKit Tse1, DaoWei Zhu3, Hui Zheng1 and ShengXiang Lin3 1Department of Biochemistry, and 2Cooperative Research Center for Soluble Receptor Biology, Hong Kong University of Science and Technology, Clear Water Bay,Hong Kong, China. X ray crystallization of recombinant membrane proximal structural domain of human GABAA receptor α1 subunit overexpressed in Escherichia coli www.iscb.org /ismb2004/posters/hxueATust.hk_960.html   (297 words)

Rigaku -- About X-ray Diffraction The possibility of using powder diffraction methods to study materials was recognized shortly after the discovery of X-ray diffraction by von Laüe and Knipping in 1910. As a consequence, powder diffraction has been transformed into one of the most exciting areas in scientific instrumentation. The power of powder techniques is such that they have had an impact in most of the major developments in the field of new materials during recent years - with solid electrolytes, high-temperature superconductors, fullerenes, zeolites and giant magnetoresistance (GMR) materials being obvious examples. www.msc.com /xrd/about.html   (164 words)

THE DIFFRACTION CONTRAPTION X ray diffraction of DNA can be modeled using a light source with a longer wavelength and a proportionately larger helix. The first x-ray diffraction pictures of DNA were obtained by Astbury and published in 1947, from which the 3.4Å spacing between nucleotides was deduced. Although the next 20 years of research in molecular biology confirmed, indirectly, the DNA structure, it wasn't until the 1980's that a detailed X ray diffraction picture of a crystal DNA structure was obtained. www.rpc.msoe.edu /sepa/preview/sec4/4-a-9.htm   (1255 words)

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