{"title":"AutoRefl: active learning in neutron reflectometry for fast data acquisition","authors":"David P. Hoogerheide, Frank Heinrich","doi":"10.1107/S1600576724006447","DOIUrl":"https://doi.org/10.1107/S1600576724006447","url":null,"abstract":"<p>Neutron reflectometry (NR) is a powerful technique for interrogating the structure of thin films at interfaces. Because NR measurements are slow and instrument availability is limited, measurement efficiency is paramount. One approach to improving measurement efficiency is active learning (AL), in which the next measurement configurations are selected on the basis of information gained from the partial data collected so far. <i>AutoRefl</i>, a model-based AL algorithm for neutron reflectometry measurements, is presented in this manuscript. <i>AutoRefl</i> uses the existing measurements of a function to choose both the position and the duration of the next measurement. <i>AutoRefl</i> maximizes the information acquisition rate in specific model parameters of interest and uses the well defined signal-to-noise ratio in counting measurements to choose appropriate measurement times. Since continuous measurement is desirable for practical implementation, <i>AutoRefl</i> features forecasting, in which the optimal positions of multiple future measurements are predicted from existing measurements. The performance of <i>AutoRefl</i> is compared with that of well established best practice measurements for supported lipid bilayer samples using realistic digital twins of monochromatic and polychromatic reflectometers. <i>AutoRefl</i> is shown to improve NR measurement speeds in all cases significantly.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 4","pages":"1192-1204"},"PeriodicalIF":5.2,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968405","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":"Modulated crystallographic shear structure in titanium–chromium oxides: their structure and phonon-transport properties","authors":"Shunta Harada, Taiga Hattori, Mai Inden, Shunya Sugimoto, Manaho Ito, Miho Tagawa, Toru Ujihara","doi":"10.1107/S1600576724006381","DOIUrl":"https://doi.org/10.1107/S1600576724006381","url":null,"abstract":"<p>Advancements in phonon engineering have propelled the study of heat conduction within nanostructures, focusing on the wave nature of phonons for thermal conductivity manipulation. This work investigates the annealing-induced structural transformation of titanium–chromium oxide crystals, highlighting a role in modulating thermal conductivity through the regularization of crystallographic shear (CS) plane spacing. Utilizing high-angle annular dark-field scanning transmission electron microscopy and selected-area electron diffraction, a transformation from disordered to ordered arrangements of CS planes was observed through annealing at high temperatures. The thermal conductivity increased following annealing. The variability observed in the spacing of CS planes before annealing implies that phonon Anderson localization might play a role in the changes in thermal conductivity.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 4","pages":"1212-1216"},"PeriodicalIF":5.2,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968292","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}
Richard A. Sykes, Natalie T. Johnson, Christopher J. Kingsbury, Jürgen Harter, Andrew G. P. Maloney, Isaac J. Sugden, Suzanna C. Ward, Ian J. Bruno, Stewart A. Adcock, Peter A. Wood, Patrick McCabe, Alexandru A. Moldovan, Francis Atkinson, Ilenia Giangreco, Jason C. Cole
{"title":"What has scripting ever done for us? The CSD Python application programming interface (API)","authors":"Richard A. Sykes, Natalie T. Johnson, Christopher J. Kingsbury, Jürgen Harter, Andrew G. P. Maloney, Isaac J. Sugden, Suzanna C. Ward, Ian J. Bruno, Stewart A. Adcock, Peter A. Wood, Patrick McCabe, Alexandru A. Moldovan, Francis Atkinson, Ilenia Giangreco, Jason C. Cole","doi":"10.1107/S1600576724005934","DOIUrl":"https://doi.org/10.1107/S1600576724005934","url":null,"abstract":"<p>Since its first release in 2016, the Cambridge Structural Database Python application programming interface (CSD Python API) has seen steady uptake within the community that the Cambridge Crystallographic Data Centre serves. This article reviews the history of scripting interfaces, demonstrating the need, and then briefly outlines the technical structure of the API. It describes the reach of the CSD Python API, provides a selected review of its impact and gives some illustrative examples of what scientists can do with it. The article concludes with speculation as to how such endeavours will evolve over the next decade.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 4","pages":"1235-1250"},"PeriodicalIF":5.2,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968280","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}
Nickolay Arkhipov, Alexander Ganzha, Maria Kniazeva, Alexander Vakulenko, Alexey Filimonov, Roman Burkovsky
{"title":"In situ X-ray diffraction evidence of field-induced transitions in a PbHfO3 single crystal","authors":"Nickolay Arkhipov, Alexander Ganzha, Maria Kniazeva, Alexander Vakulenko, Alexey Filimonov, Roman Burkovsky","doi":"10.1107/S1600576724006393","DOIUrl":"https://doi.org/10.1107/S1600576724006393","url":null,"abstract":"<p>Antiferroelectric (AFE) materials are interesting due to recent discoveries of new prospective applications, although the mechanisms of the phase transitions that are at the heart of these applications remain incompletely understood. This work is devoted to the study of a single crystal of a model AFE, lead hafnate, by X-ray diffraction with <i>in situ</i> application of an electric field to trigger the transition to a polar phase. Two consecutive experiments were carried out on a 35 µm thick plate with [110] surface normal orientation over a field range from 0 to 330 kV cm<sup>−1</sup> and back. A sharp drop in the intensity of <i>R</i>- and Σ-type reflections around 225 kV cm<sup>−1</sup> was registered, with almost complete disappearance after 250 kV cm<sup>−1</sup>. This is compatible with a field-induced phase transition from the AFE to the <i>R</i>3<i>m</i> polar phase, which was suggested earlier on the basis of non-diffraction characterizations. X-ray diffraction reveals that the AFE domains with displacements parallel to the field direction react much more smoothly to the field, gradually reducing the AFE order at very small fields instead of holding it almost constant up to the critical field value, which is naturally expected. This expectation is fulfilled for domains with other orientations, but only for the first switching cycle; in the second switching cycle the AFE order already shows a notable decrease at subcritical fields. It is suggested that these observations could be linked with the antiphase domain wall population being affected by the field, which is consistent with the observation of diffuse rods between the Γ and Σ points. Another remarkable observation is the much smoother recovery of the AFE phase compared with its sharp disappearance at the critical field.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 4","pages":"1184-1191"},"PeriodicalIF":5.2,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968289","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}