X-ray absorption intensity at high-energy region

XAFS (X-ray absorption fine-structure) spectra were measured near K-absorption edges of Ce (40.5 keV), Dy (53.8 keV), Ta (67.4 keV) and Pt (78.4 keV). The blunt K-edge jump due to the finite lifetime of the core hole was observed. This makes it difficult to extract EXAFS (extended X-ray absorption fine-structure) functions at low k values. Local structure parameters can be evaluated from the EXAFS spectra above K-absorption edges in the high-energy region as well as from those above L III-edges. It was found that the finite-lifetime effect of the core hole is effectively taken into the photoelectron mean-free-path term, as predicted theoretically.

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An empirical derivation of the X-ray optic transmission profile used in calibrating the Planetary Instrument for X-ray Lithochemistry (PIXL) for Mars 2020

Powder Diffraction ◽

10.1017/s0885715618000416 ◽

2018 ◽

Vol 33 (2) ◽

pp. 162-165 ◽

Cited By ~ 1

Author(s):

C. M. Heirwegh ◽

W. T. Elam ◽

D. T. Flannery ◽

A. C. Allwood

Keyword(s):

Energy Region ◽

High Energy ◽

Conventional Approach ◽

Smoothing Algorithm ◽

Correction Factors ◽

High Energy Region ◽

X Ray ◽

Straightforward Method ◽

Specific Correction ◽

Energy Portion

Calibration of the prototype Planetary Instrument for X-ray Lithochemistry (PIXL) selected for Mars 2020 has commenced with an empirical derivation of the X-ray optic transmission profile. Through a straightforward method of dividing a measured “blank” spectrum over one calculated assuming no optic influence, a rudimentary profile was formed. A simple boxcar-smoothing algorithm was implemented to approximate the complete profile that was incorporated into PIQUANT. Use of this form of smoothing differs from the more conventional approach of using a parameter-based function to complete the profile. Comparison of element-specific correction factors, taken from a measurement of NIST SRM 610, was used to assess the accuracy of the new profile. Improvement in the low- to mid-energy portion of the data was apparent though the high-energy region diverged from unity, and thus, requires further refinement.

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Energy determination of synchrotron X-ray beam energy in the high energy region of 38–50keV using powder diffraction patterns of the standard powder Si640b

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2009.10.124 ◽

2010 ◽

Vol 619 (1-3) ◽

pp. 147-149 ◽

Cited By ~ 3

Author(s):

Nicholas A. Rae ◽

M. Tauhidul Islam ◽

Christopher T. Chantler ◽

Martin D. de Jonge

Keyword(s):

Powder Diffraction ◽

Energy Region ◽

Beam Energy ◽

High Energy ◽

High Energy Region ◽

X Ray ◽

Standard Powder ◽

Diffraction Patterns ◽

Energy Determination

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Conformational properties of N',N'-dimethylamides of N-acetyldehydroalanine and N-acetyl-(Z)-dehydrophenylalanine.

Acta Biochimica Polonica ◽

10.18388/abp.2001_3888 ◽

2001 ◽

Vol 48 (4) ◽

pp. 1179-1183 ◽

Cited By ~ 5

Author(s):

D Siodłak ◽

M A Broda ◽

B Rzeszotarska ◽

A E Kozioł ◽

I Dybała

Keyword(s):

Energy Region ◽

High Energy ◽

High Energy Region ◽

Energy Calculations ◽

X Ray ◽

Ramachandran Map ◽

Conformational Preferences ◽

Conformational Properties

Conformational preferences of Ac-deltaAla-NMe2 and Ac-(Z)-deltaPhe-NMe2 were studied and compared with those of their monomethyl counterparts as well as with those of their saturated analogues. X-Ray data and energy calculations revealed a highly conservative conformation of the dehydro dimethylamides, which is located in a high-energy region of the Ramachandran map.

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Analysis of Shielding Performance of Radiation-Shielding Materials According to Particle Size and Clustering Effects

Applied Sciences ◽

10.3390/app11094010 ◽

2021 ◽

Vol 11 (9) ◽

pp. 4010

Author(s):

Seon-Chil Kim

Keyword(s):

Particle Size ◽

Polymer Material ◽

Energy Region ◽

High Energy ◽

Radiation Shielding ◽

High Energy Region ◽

Particle Structure ◽

Effect Of Particle Size ◽

Extensive Body ◽

Shielding Material

In the field of medical radiation shielding, there is an extensive body of research on process technologies for ecofriendly shielding materials that could replace lead. In particular, the particle size and arrangement of the shielding material when blended with a polymer material affect shielding performance. In this study, we observed how the particle size of the shielding material affects shielding performance. Performance and particle structure were observed for every shielding sheet, which were fabricated by mixing microparticles and nanoparticles with a polymer material using the same process. We observed that the smaller the particle size was, the higher both the clustering and shielding effects in the high-energy region. Thus, shielding performance can be improved. In the low-dose region, the effect of particle size on shielding performance was insignificant. Moreover, the shielding sheet in which nanoparticles and microsized particles were mixed showed similar performance to that of the shielding sheet containing only microsized particles. Findings indicate that, when fabricating a shielding sheet using a polymer material, the smaller the particles in the high-energy region are, the better the shielding performance is. However, in the low-energy region, the effect of the particles is insignificant.

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π--PInteraction in High Energy Region

Progress of Theoretical Physics ◽

10.1143/ptp.18.264 ◽

1957 ◽

Vol 18 (3) ◽

pp. 264-268 ◽

Cited By ~ 6

Author(s):

Daisuke Ito ◽

Tetsuro Kobayashi ◽

Miwae Yamazaki ◽

Shigeo Minami

Keyword(s):

Energy Region ◽

High Energy ◽

High Energy Region

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High-Energy-Resolution Fluorescence-Detected X-ray Absorption of the Q Intermediate of Soluble Methane Monooxygenase

Journal of the American Chemical Society ◽

10.1021/jacs.7b09560 ◽

2017 ◽

Vol 139 (49) ◽

pp. 18024-18033 ◽

Cited By ~ 50

Author(s):

Rebeca G. Castillo ◽

Rahul Banerjee ◽

Caleb J. Allpress ◽

Gregory T. Rohde ◽

Eckhard Bill ◽

...

Keyword(s):

Energy Resolution ◽

Methane Monooxygenase ◽

High Energy ◽

High Energy Resolution ◽

X Ray ◽

Soluble Methane Monooxygenase ◽

X Ray Absorption

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High-energy resolution X-ray absorption and emission spectroscopy reveals insight into unique selectivity of La-based nanoparticles for CO2

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1516192113 ◽

2015 ◽

Vol 112 (52) ◽

pp. 15803-15808 ◽

Cited By ~ 23

Author(s):

Ofer Hirsch ◽

Kristina O. Kvashnina ◽

Li Luo ◽

Martin J. Süess ◽

Pieter Glatzel ◽

...

Keyword(s):

Energy Resolution ◽

Emission Spectroscopy ◽

High Energy ◽

Unit Cell ◽

High Energy Resolution ◽

Electron Configuration ◽

Edge Structure ◽

X Ray ◽

X Ray Absorption

The lanthanum-based materials, due to their layered structure and f-electron configuration, are relevant for electrochemical application. Particularly, La2O2CO3 shows a prominent chemoresistive response to CO2. However, surprisingly less is known about its atomic and electronic structure and electrochemically significant sites and therefore, its structure–functions relationships have yet to be established. Here we determine the position of the different constituents within the unit cell of monoclinic La2O2CO3 and use this information to interpret in situ high-energy resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) and valence-to-core X-ray emission spectroscopy (vtc XES). Compared with La(OH)3 or previously known hexagonal La2O2CO3 structures, La in the monoclinic unit cell has a much lower number of neighboring oxygen atoms, which is manifested in the whiteline broadening in XANES spectra. Such a superior sensitivity to subtle changes is given by HERFD method, which is essential for in situ studying of the interaction with CO2. Here, we study La2O2CO3-based sensors in real operando conditions at 250 °C in the presence of oxygen and water vapors. We identify that the distribution of unoccupied La d-states and occupied O p- and La d-states changes during CO2 chemoresistive sensing of La2O2CO3. The correlation between these spectroscopic findings with electrical resistance measurements leads to a more comprehensive understanding of the selective adsorption at La site and may enable the design of new materials for CO2 electrochemical applications.

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Structural Evolution in Wet Mechanically Alloyed Co-Fe-(Ta,W)-B Alloys

Metals ◽

10.3390/met11050800 ◽

2021 ◽

Vol 11 (5) ◽

pp. 800

Author(s):

Vladimír Girman ◽

Maksym Lisnichuk ◽

Daria Yudina ◽

Miloš Matvija ◽

Pavol Sovák ◽

...

Keyword(s):

Structural Changes ◽

Magnetic Measurements ◽

Structural Evolution ◽

High Energy ◽

Control Agent ◽

X Ray Diffraction ◽

Mechanically Alloyed ◽

X Ray ◽

Transmission Electron ◽

X Ray Absorption

In the present study, the effect of wet mechanical alloying (MA) on the glass-forming ability (GFA) of Co43Fe20X5.5B31.5 (X = Ta, W) alloys was studied. The structural evolution during MA was investigated using high-energy X-ray diffraction, X-ray absorption spectroscopy, high-resolution transmission electron microscopy and magnetic measurements. Pair distribution function and extended X-ray absorption fine structure spectroscopy were used to characterize local atomic structure at various stages of MA. Besides structural changes, the magnetic properties of both compositions were investigated employing a vibrating sample magnetometer and thermomagnetic measurements. It was shown that using hexane as a process control agent during wet MA resulted in the formation of fully amorphous Co-Fe-Ta-B powder material at a shorter milling time (100 h) as compared to dry MA. It has also been shown that substituting Ta with W effectively suppresses GFA. After 100 h of MA of Co-Fe-W-B mixture, a nanocomposite material consisting of amorphous and nanocrystalline bcc-W phase was synthesized.

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