Standing wave approach in the theory of X-ray magnetic reflectivity

An extension of the exact X-ray resonant magnetic reflectivity theory has been developed, taking into account the small value of the magnetic terms in the X-ray susceptibility tensor. It is shown that squared standing waves (fourth power of the total electric field) determine the output of the magnetic addition to the total reflectivity from a magnetic multilayer. The obtained generalized kinematical approach essentially speeds up the calculation of the asymmetry ratio in the magnetic reflectivity. The developed approach easily explains the peculiarities of the angular dependence of the reflectivity with the rotated polarization (such as the peak at the critical angle of the total external reflection). The revealed dependence of the magnetic part of the total reflectivity on the squared standing waves means that the selection of the reflectivity with the rotated polarization ensures higher sensitivity to the depth profiles of magnetization than the secondary radiation at the specular reflection condition.

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X-ray standing waves—a new method of studying the structure of crystals

Uspekhi Fizicheskih Nauk ◽

10.3367/ufnr.0149.198605c.0069 ◽

1986 ◽

Vol 149 (05) ◽

pp. 69-103 ◽

Cited By ~ 60

Author(s):

M.V. Koval'chuk ◽

V.G. Kohn

Keyword(s):

Standing Waves ◽

New Method ◽

X Ray

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Real-time Approximation of Photometric Polygonal Lights

Proceedings of the ACM on Computer Graphics and Interactive Techniques ◽

10.1145/3384537 ◽

2020 ◽

Vol 3 (1) ◽

pp. 1-18

Author(s):

Christian Luksch ◽

Lukas Prost ◽

Michael Wimmer

Keyword(s):

Real Time ◽

Specular Reflection ◽

Near Field ◽

Measurement Data ◽

Data Sets ◽

Photometric Measurement ◽

Integration Technique ◽

Time Approximation ◽

Light Emitter ◽

Selection Of

We present a real-time rendering technique for photometric polygonal lights. Our method uses a numerical integration technique based on a triangulation to calculate noise-free diffuse shading. We include a dynamic point in the triangulation that provides a continuous near-field illumination resembling the shape of the light emitter and its characteristics. We evaluate the accuracy of our approach with a diverse selection of photometric measurement data sets in a comprehensive benchmark framework. Furthermore, we provide an extension for specular reflection on surfaces with arbitrary roughness that facilitates the use of existing real-time shading techniques. Our technique is easy to integrate into real-time rendering systems and extends the range of possible applications with photometric area lights.

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X-ray standing waves reveal lack of OH termination at hydroxylated ZnO(0001) surfaces

Physical Review Materials ◽

10.1103/physrevmaterials.4.020602 ◽

2020 ◽

Vol 4 (2) ◽

Cited By ~ 1

Author(s):

Jens Niederhausen ◽

Antoni Franco-Cañellas ◽

Simon Erker ◽

Thorsten Schultz ◽

Katharina Broch ◽

...

Keyword(s):

Standing Waves ◽

X Ray

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Molecular Dynamics Simulation of the Influence of RDX Internal Defects on Sensitivity

Crystals ◽

10.3390/cryst11040329 ◽

2021 ◽

Vol 11 (4) ◽

pp. 329

Author(s):

Pengmin Yan ◽

Xue Zhao ◽

Jiuhou Rui ◽

Juan Zhao ◽

Min Xu ◽

...

Keyword(s):

Energetic Materials ◽

Low Cost ◽

Relative Sensitivity ◽

Dynamics Simulation ◽

Safety Properties ◽

Internal Defects ◽

X Ray ◽

X Ray Computed ◽

Low Sensitivity ◽

Higher Sensitivity

The internal defect is an important factor that could influence the energy and safety properties of energetic materials. RDX samples of two qualities were characterized and simulated to reveal the influence of different defects on sensitivity. The internal defects were characterized with optical microscopy, Raman spectroscopy and microfocus X-ray computed tomography technology. The results show that high-density RDX has fewer defects and a more uniform distribution. Based on the characterization results, defect models with different defect rates and distribution were established. The simulation results show that the models with fewer internal defects lead to shorter N-NO2 maximum bond lengths and greater cohesive energy density (CED). The maximum bond length and CED can be used as the criterion for the relative sensitivity of RDX, and therefore defect models doped with different solvents are established. The results show that the models doped with propylene carbonate and acetone lead to higher sensitivity. This may help to select the solvent to prepare low-sensitivity RDX. The results reported in this paper are aiming at the development of a more convenient and low-cost method for studying the influence of internal defects on the sensitivity of energetic materials.

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