Acta Crystallographica Section A: Foundations and Advances最新文献

Deconvoluting thermomechanical effects in X-ray diffraction data using machine learning.

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-01-31 DOI: 10.1107/S2053273325000403

Rachel E Lim, Shun Li Shang, Chihpin Chuang, Thien Q Phan, Zi Kui Liu, Darren C Pagan

{"title":"Deconvoluting thermomechanical effects in X-ray diffraction data using machine learning.","authors":"Rachel E Lim, Shun Li Shang, Chihpin Chuang, Thien Q Phan, Zi Kui Liu, Darren C Pagan","doi":"10.1107/S2053273325000403","DOIUrl":"10.1107/S2053273325000403","url":null,"abstract":"X-ray diffraction is ideal for probing the sub-surface state during complex or rapid thermomechanical loading of crystalline materials. However, challenges arise as the size of diffraction volumes increases due to spatial broadening and because of the inability to deconvolute the effects of different lattice deformation mechanisms. Here, we present a novel approach that uses combinations of physics-based modeling and machine learning to deconvolve thermal and mechanical elastic strains for diffraction data analysis. The method builds on a previous effort to extract thermal strain distribution information from diffraction data. The new approach is applied to extract the evolution of the thermomechanical state during laser melting of an Inconel 625 wall specimen which produces significant residual stress upon cooling. A combination of heat transfer and fluid flow, elasto-plasticity and X-ray diffraction simulations is used to generate training data for machine-learning (Gaussian process regression, GPR) models that map diffracted intensity distributions to underlying thermomechanical strain fields. First-principles density functional theory is used to determine accurate temperature-dependent thermal expansion and elastic stiffness used for elasto-plasticity modeling. The trained GPR models are found to be capable of deconvoluting the effects of thermal and mechanical strains, in addition to providing information about underlying strain distributions, even from complex diffraction patterns with irregularly shaped peaks.","PeriodicalId":106,"journal":{"name":"Acta Crystallographica Section A: Foundations and Advances","volume":" ","pages":"137-150"},"PeriodicalIF":1.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11873812/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143062184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unit-cell parameters determination from a set of independent electron diffraction zonal patterns.

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-01-31 DOI: 10.1107/S2053273325000300

Tatiana E Gorelik, Gerhard Miehe, Robert Bücker, Kaname Yoshida

引用次数: 0

Honeycombs - their variety, topology and symmetry.

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-02-14 DOI: 10.1107/S2053273325000889

Zbigniew Dauter, Mariusz Jaskolski

{"title":"Honeycombs - their variety, topology and symmetry.","authors":"Zbigniew Dauter, Mariusz Jaskolski","doi":"10.1107/S2053273325000889","DOIUrl":"10.1107/S2053273325000889","url":null,"abstract":"The double-layer honeycomb with hexagonal cells, three rhombic faces between the two layers and p3m1 layer space-group symmetry, used universally by honeybees, is often considered to be the most efficient (from the point of view of wax economy) and the only honeycomb manufactured by bees. However, another variant of a symmetric and periodic double-layer hexagonal honeycomb with two hexagons and two rhombi between the two layers and slightly better wax economy was discovered theoretically in 1964 by Fejes Tóth and found in nature some years later. The present work shows that there is yet another possibility, with the interface formed by one hexagon and two quadrangles, in addition to the trivial case with flat hexagonal cell bottoms and very poor wax economy. Moreover, we demonstrate that the geometry of the Fejes Tóth honeycomb can be optimized for even better wax economy. All the theoretical honeycomb types are derived using the principle of Dirichlet-domain construction and shown to have more and less symmetric variants. Wax economy is calculated for each case, confirming that indeed the modified Fejes Tóth honeycomb is the most efficient, while the trivial flat-bottom case is the least.","PeriodicalId":106,"journal":{"name":"Acta Crystallographica Section A: Foundations and Advances","volume":" ","pages":"159-166"},"PeriodicalIF":1.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11873813/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A physical optics formulation of Bloch waves and its application to 4D STEM, 3D ED and inelastic scattering simulations.

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-01-30 DOI: 10.1107/S2053273325000142

Budhika G Mendis

{"title":"A physical optics formulation of Bloch waves and its application to 4D STEM, 3D ED and inelastic scattering simulations.","authors":"Budhika G Mendis","doi":"10.1107/S2053273325000142","DOIUrl":"10.1107/S2053273325000142","url":null,"abstract":"Bloch waves are often used in dynamical diffraction calculations, such as simulating electron diffraction intensities for crystal structure refinement. However, this approach relies on matrix diagonalization and is therefore computationally expensive for large unit cell crystals. Here Bloch wave theory is re-formulated using the physical optics concepts underpinning the multislice method. In particular, the multislice phase grating and propagator functions are expressed in matrix form using elements of the Bloch wave structure matrix. The specimen is divided into thin slices, and the evolution of the electron wavefunction through the specimen calculated using the Bloch phase grating and propagator matrices. By decoupling specimen scattering from free space propagation of the electron beam, many computationally demanding simulations, such as 4D STEM imaging modes, 3D ED precession and rotation electron diffraction, phonon and plasmon inelastic scattering, are considerably simplified. The computational cost scales as {cal O}({N^2} ) per slice, compared with {cal O}({N^3} ) for a standard Bloch wave calculation, where N is the number of diffracted beams. For perfect crystals the performance can at times be better than multislice, since only the important Bragg reflections in the otherwise sparse diffraction plane are calculated. The physical optics formulation of Bloch waves is therefore an important step towards more routine dynamical diffraction simulation of large data sets.","PeriodicalId":106,"journal":{"name":"Acta Crystallographica Section A: Foundations and Advances","volume":" ","pages":"113-123"},"PeriodicalIF":1.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11873815/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143062165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Isogonal 1-periodic polycatenanes (chains). Transitivity and intransitivity of links.

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-02-14 DOI: 10.1107/S2053273325001044

Michael O'Keeffe, Michael M J Treacy

引用次数: 0

Symmetric 3-periodic polycatenanes: catenated rings, polyhedra and rods. 对称三周期聚连环烷：连环环、多面体和棒状。

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-01-09 DOI: 10.1107/S2053273324012129

Michael O'Keeffe, Michael M J Treacy

引用次数: 0

Crystallography of quasiperiodic moiré patterns in homophase twisted bilayers.

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-01-30 DOI: 10.1107/S2053273324012087

Marianne Quiquandon, Denis Gratias

引用次数: 0

Homophase bilayers: more than just the sum of their monolayers.

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-03-01 Epub Date: 2025-02-25 DOI: 10.1107/S2053273325001573

M Feuerbacher

引用次数: 0

Small-angle rigid-unit modes requiring linear strain compensation. 需要线性应变补偿的小角刚性单元模式。

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-01-01 DOI: 10.1107/S205327332401163X

Bryce T Eggers, Harold T Stokes, Branton J Campbell

引用次数: 0

Growth functions of periodic space tessellations. 周期空间镶嵌的生长函数。

IF 1.9 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2025-01-01 DOI: 10.1107/S2053273324010763

Bartosz Naskręcki, Jakub Malinowski, Zbigniew Dauter, Mariusz Jaskolski

引用次数: 0