Quantitative element analysis with an energy dispersive X‐ray fluorescence instrument equipped with a highly oriented pyrolytic graphite filter

The measurement of the mean-square thermal displacement 〈u 2〉 of carbon atoms in highly oriented pyrolytic graphite (HOPG) in the hexagonal c direction is reported. Energy-dispersive X-ray diffraction (EDXD) has been used to study the integrated intensity of all Bragg reflections 004 through 0′0′14 as a function of temperature. It is demonstrated that the correction of the Bragg intensities due to thermal diffuse scattering contributions is very important for HOPG, when EDXD is used. The Debye temperature ΘD = 554 (30) K is obtained.

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Improvement of the Detection Sensitivity of Edxrf Trace Element Analysis by Means of Efficient X-Ray Focusing Based on Strongly Curved Hopg Crystals

Advances in X-ray Analysis ◽

10.1154/s0376030800022515 ◽

1995 ◽

Vol 39 ◽

pp. 109-117

Author(s):

Burkhard Beckhoff ◽

Birgit Kanngießer

Keyword(s):

High Intensity ◽

Focal Plane ◽

Bragg Reflection ◽

Pyrolytic Graphite ◽

Trace Element Analysis ◽

Detection Sensitivity ◽

Element Analysis ◽

X Ray ◽

Wide Range ◽

Very High

X-ray focusing based on Bragg reflection at curved crystals allows collection of a large solid angle of incident radiation, monochromatization of this radiation, and condensation of the beam reflected at the crystal into a small spatial cross-section in a pre-selected focal plane. Thus, for the Bragg reflected radiation, one can achieve higher intensities than for the radiation passing directly to the same small area in the focal plane. In that case one can profit considerably from X-ray focusing in an EDXRF arrangement. The 00 2 reflection at Highly Oriented Pyrolytic Graphite (HOPG) crystals offers a very high intensity of the Bragg reflected beam for a wide range of photon energies. Furthermore, curvature radii smaller than 10 mm can be achieved for HOPG crystals ensuring efficient X-ray focusing in EDXRF applications. For the trace analysis of very small amounts of specimen material deposited on small areas of thin-filter backings, HOPG based X-ray focusing may be used to achieve a very high intensity of monochromatic excitation radiation.

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STM Analysis of a Chiral Helical Onedimensional Nickel(II) Coordination Polymer

Zeitschrift für Naturforschung B ◽

10.1515/znb-2008-1218 ◽

2008 ◽

Vol 63 (12) ◽

pp. 1443-1446 ◽

Cited By ~ 6

Author(s):

Mohammad Sahabul Alam ◽

Andreas Scheurer ◽

Rolf W. Saalfrank ◽

Paul Müller

Keyword(s):

Coordination Polymer ◽

Single Crystals ◽

Excellent Agreement ◽

Pyrolytic Graphite ◽

Highly Oriented Pyrolytic Graphite ◽

X Ray ◽

X Ray Crystallography ◽

Salen Complexes ◽

Polymeric Chains ◽

Dimeric Aggregates

C2-symmetric nickel(II) salen complexes [NiL] 1 were deposited on a highly oriented pyrolytic graphite (HOPG) surface from their acetone solutions. They aggregate easily to single, segregated, homochiral polymeric chains of (M)-1D- 1n [NiL] (2) on the substrate as also found in single crystals. In STM topography, the single helical 1D structures 2 found on the surface were in excellent agreement with the dimension of aligned dimeric aggregates of 1 obtained from X-ray crystallography. Weak intermolecular NiII...OMe coordinations (dMeO−Ni = 0.35 nm) were found to be responsible for the formation of the chiral, helical and 1D assemblies on the substrate.

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Otospongiosis: Morphologic and Microchemical Investigation after Naf-Treatment

Otolaryngology ◽

10.1177/019459988108900425 ◽

1981 ◽

Vol 89 (4) ◽

pp. 646-650 ◽

Cited By ~ 5

Author(s):

Paul Bretlau ◽

Hans Jørgen Hansen ◽

Jean Causse ◽

Jean-Bernard Causse

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Sodium Fluoride ◽

Energy Dispersive ◽

Blind Study ◽

Element Analysis ◽

X Ray ◽

Scanning Electron

Element analysis of microareas of otospongiotic specimens is described. A total of 36 otospongiotic stapes are ultrasectioned without decalcification and examined using a transmission and a scanning electron microscope (STEM-mode). The latter was equipped with an energy dispersive x-ray analyzer. Twenty of the stapes came from patients who have had sodium fluoride (NaF) treatment (15 to 45 mg/day) for a minimum of 12 months. The otospongiotic stapes are classified as spongiotic and sclerotic according to their pathologic characteristics and state of mineralization. Using the Ca/P ratio as criterion—measured by the characteristic x-ray fluorescence—it was shown in a blind study that the NaF-treated otospongiotic stapes had a statistically higher Ca/P ratio, indicating that the fluoride may stabilize otospongiotic lesions, particularly the spongiotic type with unstable mineralization.

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Protein bodies in Datura stramonium seeds: structure and mineral nutrient composition

Canadian Journal of Botany ◽

10.1139/b91-317 ◽

1991 ◽

Vol 69 (11) ◽

pp. 2545-2554 ◽

Cited By ~ 8

Author(s):

Sara Maldonado ◽

John N. A. Lott

Keyword(s):

Distribution Patterns ◽

Cell Types ◽

Datura Stramonium ◽

Energy Dispersive ◽

Protein Bodies ◽

Mineral Nutrient ◽

Electron Microscopic ◽

Element Analysis ◽

X Ray ◽

Endosperm Protein

The structure of protein bodies in the endosperm and embryo of Datura stramonium was studied with a variety of light-and electron-microscopic techniques. Protein bodies had one to several globoid crystals and one or two protein crystalloids in the proteinaceous matrix. Although the embryo protein bodies rarely had more than two globoid crystals, the endosperm protein bodies had varying sizes and numbers of globoid crystals, even within the same cell. Energy-dispersive X-ray analysis of globoid crystals revealed the presence of P, K, and Mg in all cases. Traces of Fe, Mn, and Zn were also found in globoid crystals of protein bodies from certain cell types. The distribution patterns of these three elements were quite specific; for example, Mn traces were found only in the globoid crystals of the protoderm. Neutron-activation analysis of endosperm and embryo tissues was used to quantitatively measure the concentration of Ca, Cl, Cu, I, K, Mg, Mn, Na, and S. The results from structural studies and the element analysis studies are discussed in the context of solanaceous seeds in particular but also with relation to seeds in general. Key words: protein bodies, Datura stramonium, seed, globoid crystals, energy-dispersive X-ray analysis, Solanaceae.

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X-Ray Diffuse Scattering by Highly Oriented Pyrolytic Graphite

Journal of the Physical Society of Japan ◽

10.1143/jpsj.59.959 ◽

1990 ◽

Vol 59 (3) ◽

pp. 959-964 ◽

Cited By ~ 3

Author(s):

Teruyuki Tamaki ◽

Nobuyoshi Wakabayashi

Keyword(s):

Diffuse Scattering ◽

Pyrolytic Graphite ◽

Highly Oriented Pyrolytic Graphite ◽

X Ray

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Double Bragg scattering observed in small-angle X-ray scattering from highly oriented pyrolytic graphite

Journal of Applied Crystallography ◽

10.1107/s1600576716004568 ◽

2016 ◽

Vol 49 (3) ◽

pp. 835-844 ◽

Cited By ~ 8

Author(s):

Yoshinori Ohmasa ◽

Susumu Shimomura ◽

Ayano Chiba

Keyword(s):

Small Angle ◽

Small Deviation ◽

Pyrolytic Graphite ◽

Bragg Scattering ◽

Highly Oriented Pyrolytic Graphite ◽

Finite Sample ◽

X Ray ◽

Sample Rotation ◽

X Ray Scattering ◽

Ray Scattering

In small-angle X-ray scattering from highly oriented pyrolytic graphite, radial streak patterns are observed. The streaks change their direction with sample rotation and appear and disappear in pairs. This streak pattern can be explained by double Bragg scattering. The directions of the streaks calculated as functions of the rotation angle are in good agreement with experiment. In addition, asymmetry in the intensity of the streaks and a small deviation from the radial pattern are observed, and they can be explained by the finite sample-size effect. The necessity of taking double Bragg scattering into account in small-angle X-ray scattering studies of crystalline materials is emphasized.

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