Jiaming Kang, Mingke Tan, Zhenling Huang, Tai Li, Xiang Zhou, Guoqiang Lv, Xingwei Yang, Wenhui Ma
{"title":"Effect of gap design of a double-layer heater on melt flow behavior in a single-crystal furnace","authors":"Jiaming Kang, Mingke Tan, Zhenling Huang, Tai Li, Xiang Zhou, Guoqiang Lv, Xingwei Yang, Wenhui Ma","doi":"10.1107/S1600576725002699","DOIUrl":"https://doi.org/10.1107/S1600576725002699","url":null,"abstract":"<p>The application of double-layer heaters in single-crystal furnaces holds great promise for single-crystal silicon rod production, but the absence of sufficient supporting research literature has hindered rapid progress in practical applications. In the current work, the relationship between the design of the double-layer heater and the flow behavior in the melt was obtained by investigating the lengths of the upper and lower layers of the double-layer heater and the gap position. The <i>FEMAG</i> single-crystal growth simulation platform (https://www.femagsoft.com) was adopted to simulate the growth model of M10 large-sized <i>n</i>-type single crystals. The mechanism of influence of the double-layer heater gap design on the melt flow behavior was obtained by taking the melt heating and heater radiation characteristics as the entry point and finally adopting the oxygen content in the crystal as a quality criterion. The results indicate that movement of the gap position can alter the heat-transfer conditions, thereby changing the intensity or volume of the three main vortices in the melt, which in turn affect the oxygen transport capacity.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 3","pages":"832-844"},"PeriodicalIF":5.2,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Artem S. Borisov, Veronika R. Abdulina, Oleg I. Siidra, Victoria A. Ginga, Alexander A. Tsirlin, Astrid Holzheid, Annika Zapfe, Yurii Skourski, Annette Setzer
{"title":"Thermal behavior of römerite over a Mars surface relevant temperature range: single-crystal and powder X-ray crystallography and magnetic properties","authors":"Artem S. Borisov, Veronika R. Abdulina, Oleg I. Siidra, Victoria A. Ginga, Alexander A. Tsirlin, Astrid Holzheid, Annika Zapfe, Yurii Skourski, Annette Setzer","doi":"10.1107/S1600576725002572","DOIUrl":"https://doi.org/10.1107/S1600576725002572","url":null,"abstract":"<p>A number of hydrous iron sulfate minerals have been detected on the surface of Mars under extraterrestrial conditions. Nonetheless, certain inquiries regarding the properties and phase evolution of hydrous iron sulfate minerals remain unresolved and subject to debate at present. In our research, the behavior of römerite, Fe<sup>2+</sup>Fe<sup>3+</sup><sub>2</sub>(SO<sub>4</sub>)<sub>4</sub>(H<sub>2</sub>O)<sub>14</sub>, was examined by utilizing <i>in situ</i> single-crystal and powder X-ray diffraction while simultaneously acquiring data upon heating. Römerite is stable under low-vacuum conditions. It exhibits a significant negative thermal expansion in the α<sub>33</sub> direction throughout the entire temperature range from −173 to 77°C and on up to decomposition. There is a cooperative interaction between the rotation of the sulfate tetrahedra in the [Fe<sup>3+</sup>(SO<sub>4</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]<sup>−</sup> clusters and the features of the hydrogen-bond system that determines the thermal expansion of römerite. The structure of römerite shows that the sulfate tetrahedra are the most rigid complexes, followed by the Fe2<sup>3+</sup>O<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub> octahedra, and the Fe1<sup>2+</sup>(H<sub>2</sub>O)<sub>6</sub> octahedra are the most flexible. High-temperature powder X-ray diffraction, thermogravimetry and differential scanning calorimetry were used to determine the phase transformations and the eventual decomposition of römerite at higher temperatures up to 740°C. The decomposition of römerite at 60°C is followed by an amorphization, a transformation into a mikasaite-like phase at ∼275°C and a further decomposition into a hematite-like phase above 550°C, associated with the high-temperature form of magnetite, Fe<sub>3</sub>O<sub>4</sub>, above 575°C. The magnetic behavior of römerite reveals weak interactions between the Fe<sup>2+</sup> and Fe<sup>3+</sup> centers, in line with the large spatial separation between these ions.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 3","pages":"822-831"},"PeriodicalIF":5.2,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A global optimization approach to automated indexing of fiber diffraction patterns","authors":"Tianyi Ma, Wenxian Hu, Dujin Wang, Guoming Liu","doi":"10.1107/S1600576725001906","DOIUrl":"https://doi.org/10.1107/S1600576725001906","url":null,"abstract":"<p>Accurate determination of cell parameters from two-dimensional wide-angle X-ray diffraction patterns of oriented polymer crystals is critical for structural analysis. This process, known as indexing, can be challenging due to the complexity of the diffraction patterns. Here, we introduce a method that synergistically combines genetic algorithms with gradient-based optimization techniques to progressively refine diffraction pattern matching. This approach is implemented in an automated computational tool named <i>PolymCrystIndex</i>. The method's versatility allows it to be applied to various crystal systems, including orthorhombic, monoclinic and triclinic, as demonstrated by its successful testing on experimental data from different polymers. <i>PolymCrystIndex</i> will provide a fast and reliable solution for indexing fiber patterns and obtaining accurate cell parameters, advancing the field of polymer crystallography.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 3","pages":"759-767"},"PeriodicalIF":5.2,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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