Acta Crystallographica Section A: Foundations and Advances最新文献_第3页

On geometric tubular polyhedra of types 2₀₁ and 2₁. 201型和21型几何管状多面体的研究。

IF 1.8 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-05-01 Epub Date: 2026-04-28 DOI: 10.1107/S2053273326003025

Daniel Pellicer, Gordon Williams

引用次数: 0

X-ray dynamical diffraction wavefront division interferometer (double-slit diffraction) with an asymmetric monochromator. Corrigendum. 非对称单色x射线动态衍射波前分割干涉仪（双缝衍射）。应改正的错误。

IF 1.8 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-05-01 Epub Date: 2026-03-26 DOI: 10.1107/S2053273326002287

Vahram Mkrtchyan, Minas Balyan, Sargis Petrosyan, Ashot Aivazyan

引用次数: 0

Glass bead games: enumeration of possible polytypes based on two stacking vectors and applications to the iron-ore sinter phases SFCA and SFCA-I. 玻璃珠游戏：基于两个堆叠向量的可能多型枚举及其在铁矿石烧结相SFCA和SFCA- 1中的应用。

IF 2.1 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-05-01 Epub Date: 2026-04-23 DOI: 10.1107/S2053273326003505

Michael Francesco Salzmann, Volker Kahlenberg, Hannes Krüger, Tim Netzer

{"title":"Glass bead games: enumeration of possible polytypes based on two stacking vectors and applications to the iron-ore sinter phases SFCA and SFCA-I.","authors":"Michael Francesco Salzmann, Volker Kahlenberg, Hannes Krüger, Tim Netzer","doi":"10.1107/S2053273326003505","DOIUrl":"10.1107/S2053273326003505","url":null,"abstract":"Polytypes can occur in many inorganic and organic compounds alike. In the most basic scenario, different polytypes of a compound are based on translationally equivalent layers and two equivalent arrangements of adjacent layers. This means there are only two distinct stacking vectors, t1 and t2. For this particular situation, we have enumerated the number of principally different polytypes for a given number m of layers in the stacking sequence, under the assumption of the validity of four constraints: (i) periodicity, (ii) exchangeability, (iii) reversibility and (iv) simplicity. Different results are obtained when the reversibility constraint is overturned, a factor that depends on the polar or non-polar character of the underlying layers. The results of this theoretical study have been applied to derive the existing polytypes up to m = 6 for two different polysomes of the family of so-called silico-ferrites of calcium and aluminium (SFCA and SFCA-I, respectively). These phases are of considerable interest to the steel industry, as they represent the primary constituents of the matrix in iron-ore sinters. Finally, the impact of polytypism on the powder diffraction patterns of the SFCAs was investigated and the influence of stacking disorder on the diffractograms was analysed. The resulting collection of simulated powder diffraction patterns may serve as a reference database for the identification of polytype effects in industrial sinters.","PeriodicalId":106,"journal":{"name":"Acta Crystallographica Section A: Foundations and Advances","volume":"82 Pt 3","pages":"145-162"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131315/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147757887","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

The growth and structural characterization of a La_0.67Sr_0.33MnO₃/BaTiO₃ superstructure (superlattice). La0.67Sr0.33MnO3/BaTiO3超结构（超晶格）的生长与结构表征

IF 1.8 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-05-01 Epub Date: 2026-04-16 DOI: 10.1107/S205327332600313X

Łukasz Kokosza, Jakub Pawlak, Marianna Marciszko-Wiąckowska, Grzegorz Cios, Piotr Jabłoński, Andrii Naumov, Marek Przybylski, Zbigniew Mitura

引用次数: 0

Revisiting Becker-Coppens (1974): updated recipes for estimating extinction factors in spherical crystallites. 贝克尔-科本斯（1974）：估算球形晶体中消光因子的更新配方。

IF 1.8 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-05-01 Epub Date: 2026-03-16 DOI: 10.1107/S2053273326001245

Thomas Kittelmann, Douglas D DiJulio, Shuqi Xu, J I Márquez Damián

{"title":"Revisiting Becker-Coppens (1974): updated recipes for estimating extinction factors in spherical crystallites.","authors":"Thomas Kittelmann, Douglas D DiJulio, Shuqi Xu, J I Márquez Damián","doi":"10.1107/S2053273326001245","DOIUrl":"10.1107/S2053273326001245","url":null,"abstract":"A technical correction and update of the widely used recipes by Becker & Coppens [Acta Cryst. (1974), A30, 129-147], for the estimation of primary and secondary extinction factors in perfect spherical crystallites or grains, is presented. In the original work, these extinction factors were evaluated numerically from a complicated integral, and simplified analytical approximations to these evaluations constituted the provided recipes. However, these original recipes are plagued by issues of numerical precision in general, and even suffer from complete numerical breakdown in the case of strong extinction effects, especially in backwards scattering. Using modern computing capabilities, the numerical evaluations of the integrals are revisited, and improved recipes are provided with consistent precision guarantees for all Bragg angles and levels of extinction. The new recipes are provided both in a `standard' version, believed to be of suitable precision for any actual analysis of diffraction or transmission data, and a `luxury' reference version with even higher precision. The performance of the new recipes is compared with that of the original work, and in order to facilitate easy adoption by the community, reference implementations are provided for C, C++ and Python languages.","PeriodicalId":106,"journal":{"name":"Acta Crystallographica Section A: Foundations and Advances","volume":" ","pages":"163-178"},"PeriodicalIF":1.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147466223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Structural investigation and C₆₀ adsorption on the (100) surface of a 1/1 pseudo-Tsai-type Au-Si-Ho quasicrystalline approximant. 1/1伪tsai型Au-Si-Ho准晶近似物的结构研究及C60在（100）表面的吸附。

IF 1.8 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-03-01 Epub Date: 2026-01-09 DOI: 10.1107/S2053273325011040

Wilfried Bajoun Mbajoun, Yu Chin Huang, Girma Hailu Gebresenbut, Cesar Pay Gómez, Vincent Fournée, Julian Ledieu

{"title":"Structural investigation and C60 adsorption on the (100) surface of a 1/1 pseudo-Tsai-type Au-Si-Ho quasicrystalline approximant.","authors":"Wilfried Bajoun Mbajoun, Yu Chin Huang, Girma Hailu Gebresenbut, Cesar Pay Gómez, Vincent Fournée, Julian Ledieu","doi":"10.1107/S2053273325011040","DOIUrl":"10.1107/S2053273325011040","url":null,"abstract":"Tsai-type 1/1 quasicrystalline approximants in the Au-Si-RE (RE = Ho, Tb) system are body-centered cubic phases decorated by clusters having their inner part occupied by either a disordered tetrahedron (IT) or a single rare-earth atom (CC). The system investigated in the present study is the Au-Si-Ho(CC) compound having full occupation of the cluster centers by single Ho atoms. We present a detailed study of the structure and reactivity of its (100) surface using scanning tunneling microscopy and X-ray photoelectron spectroscopy. After annealing Au-Si-Ho(CC) between 725 K and 880 K, the surface exhibits a (2 × 2) surface reconstruction. The surface appears to terminate at specific bulk planes intersecting Tsai-type cluster centers. Adsorption of C60 molecules on this surface leads to a film with a hexagonal structure corresponding to a (111) plane of the C60 bulk structure. Compared with a previous report on the (100) surface of the Au-Si-Ho 1/1 approximant having a mixed IT and CC decoration, it appears that cluster center decoration does not affect the surface plane selection rule in Tsai-type approximants. However, the inner decoration affects the atomic structure within the selected surface termination and the structure of C60 thin films formed on these surfaces.","PeriodicalId":106,"journal":{"name":"Acta Crystallographica Section A: Foundations and Advances","volume":" ","pages":"103-107"},"PeriodicalIF":1.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145931318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exploring oxide quasicrystals in internal space. 探索内部空间中的氧化物准晶体。

IF 2.1 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-03-01 Epub Date: 2026-01-09 DOI: 10.1107/S2053273325011015

Sebastian Schenk, Martin Haller, Stefan Förster, Wolf Widdra

{"title":"Exploring oxide quasicrystals in internal space.","authors":"Sebastian Schenk, Martin Haller, Stefan Förster, Wolf Widdra","doi":"10.1107/S2053273325011015","DOIUrl":"10.1107/S2053273325011015","url":null,"abstract":"Quantitative assessment of the structural quality of quasicrystals is a challenging task. Whereas diffraction techniques are a powerful tool for the coherently scattering regions, only diffuse scattering addresses structural inhomogeneities. Alternatively, local imaging techniques allow for direct inspection of the structures and for statistical evaluation of tiling elements. In both cases, inspecting the internal space characteristic for quasicrystals offers an additional, more sensitive perspective. Here, we analyze atomically resolved scanning tunneling microscopy images for three dodecagonal oxide quasicrystal (OQC) systems. Upon uplifting the 2D coordinates into a 4D hyperspace, the quasicrystal structure can be discussed in the internal space as well as in the physical space. The quasicrystal acceptance domain in internal space of all three OQCs increases logarithmically with the system size. From the acceptance domain expansion we determine the effective phason elastic constants, which reflect phason disorder within their square-triangle-rhombus tiling.","PeriodicalId":106,"journal":{"name":"Acta Crystallographica Section A: Foundations and Advances","volume":" ","pages":"87-95"},"PeriodicalIF":2.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12954487/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145931296","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

Approximate lattice matching in three dimensions. 在三维中近似的点阵匹配。

IF 2.1 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-03-01 Epub Date: 2026-02-19 DOI: 10.1107/S2053273326000781

Lawrence C Andrews, Herbert J Bernstein

引用次数: 0

Primitive icosahedral quasicrystals in ZnMgLi(Dy, Ho, Er, Tm) systems. ZnMgLi（Dy, Ho, Er, Tm）体系中的原始二十面体准晶。

IF 2.1 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-03-01 Epub Date: 2026-01-22 DOI: 10.1107/S205327332501099X

Ireneusz Buganski, Stanislav Vrtnik, Radoslaw Strzalka, Andreja Jelen, Sandra Drev, Janusz Wolny, Nobuhisa Fujita

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Minimal-transitivity finite tangles and catenated polyhedra. 最小传递性有限缠结和链状多面体。

IF 1.8 4区材料科学

Acta Crystallographica Section A: Foundations and Advances Pub Date : 2026-03-01 Epub Date: 2026-01-22 DOI: 10.1107/S2053273326000252

Michael O'Keeffe, Michael M J Treacy

引用次数: 0