Pub Date : 2024-04-15DOI: 10.1107/s1600576724002243
Lu, Y., Duman, R., Beilsten-Edmands, J., Winter, G., Basham, M., Evans, G., Kamps, J.J.A.G., Orville, A.M., Kwong, H.-S., Beis, K., Armour, W., Wagner, A.
{"title":"Ray-tracing analytical absorption correction for X-ray crystallography based on tomographic reconstructions","authors":"Lu, Y., Duman, R., Beilsten-Edmands, J., Winter, G., Basham, M., Evans, G., Kamps, J.J.A.G., Orville, A.M., Kwong, H.-S., Beis, K., Armour, W., Wagner, A.","doi":"10.1107/s1600576724002243","DOIUrl":"https://doi.org/10.1107/s1600576724002243","url":null,"abstract":"","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140564542","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}
Pub Date : 2024-04-15DOI: 10.1107/s1600576724002140
Khakurel, K.P., Nemergut, M., Džupponová, V., Kropielnicki, K., Savko, M., Žoldák, G., Andreasson, J.
{"title":"Design and fabrication of 3D-printed in situ crystallization plates for probing microcrystals in an external electric field","authors":"Khakurel, K.P., Nemergut, M., Džupponová, V., Kropielnicki, K., Savko, M., Žoldák, G., Andreasson, J.","doi":"10.1107/s1600576724002140","DOIUrl":"https://doi.org/10.1107/s1600576724002140","url":null,"abstract":"","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140603294","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}
Pub Date : 2024-04-15DOI: 10.1107/s160057672400219x
De Graef, M.
{"title":"Applications of the Clifford torus to material textures","authors":"De Graef, M.","doi":"10.1107/s160057672400219x","DOIUrl":"https://doi.org/10.1107/s160057672400219x","url":null,"abstract":"","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140564798","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}
Pub Date : 2024-03-31DOI: 10.1107/s1600576724001730
A. Tiwari, Matteo Monai, Ksenia Matveevskii, Sergey N. Yakunin, L. Mandemaker, Martina Tsvetanova, Melissa J. Goodwin, M. Ackermann, Florian Meirer, I. Makhotkin
The strong metal–support interaction (SMSI) is a phenomenon observed in supported metal catalyst systems in which reducible metal oxide supports can form overlayers over the surface of active metal nanoparticles (NPs) under a hydrogen (H2) environment at elevated temperatures. SMSI has been shown to affect catalyst performance in many reactions by changing the type and number of active sites on the catalyst surface. Laboratory methods for the analysis of SMSI at the nanoparticle-ensemble level are lacking and mostly based on indirect evidence, such as gas chemisorption. Here, we demonstrate the possibility to detect and characterize SMSIs in Co/TiO x model catalysts using the laboratory X-ray standing wave (XSW) technique for a large ensemble of NPs at the bulk scale. We designed a thermally stable MoN x /SiN x periodic multilayer to retain XSW generation after reduction with H2 gas at 600°C. The model catalyst system was synthesized here by deposition of a thin TiO x layer on top of the periodic multilayer, followed by Co NP deposition via spare ablation. A partial encapsulation of Co NPs by TiO x was identified by analyzing the change in Ti atomic distribution. This novel methodological approach can be extended to observe surface restructuring of model catalysts in situ at high temperature (up to 1000°C) and pressure (≤3 mbar), and can also be relevant for fundamental studies in the thermal stability of membranes, as well as metallurgy.
强金属-载体相互作用（SMSI）是在载体金属催化剂体系中观察到的一种现象，即在高温氢气（H2）环境下，可还原金属氧化物载体可在活性金属纳米粒子（NPs）表面形成覆盖层。事实证明，SMSI 会改变催化剂表面活性位点的类型和数量，从而影响催化剂在许多反应中的性能。目前还缺乏在纳米粒子组合水平上分析 SMSI 的实验室方法，这些方法大多基于间接证据，如气体化学吸附。在此，我们展示了利用实验室 X 射线驻波 (XSW) 技术检测和表征 Co/TiO x 模型催化剂中大量 NPs 的 SMSI 的可能性。我们设计了一种热稳定的 MoN x /SiN x 周期性多层膜，以便在 600°C 下用 H2 气体还原后保持 XSW 的产生。这里合成的催化剂体系模型是在周期性多层膜上沉积一层薄的 TiO x，然后通过备用烧蚀沉积 Co NP。通过分析 Ti 原子分布的变化，确定了 TiO x 对 Co NPs 的部分封装。这种新颖的方法可扩展到在高温（高达 1000°C）和高压（≤3 毫巴）下原位观察模型催化剂的表面重组，也可用于膜热稳定性和冶金学的基础研究。
{"title":"X-ray standing wave characterization of the strong metal–support interaction in Co/TiO\u0000 x\u0000 model catalysts","authors":"A. Tiwari, Matteo Monai, Ksenia Matveevskii, Sergey N. Yakunin, L. Mandemaker, Martina Tsvetanova, Melissa J. Goodwin, M. Ackermann, Florian Meirer, I. Makhotkin","doi":"10.1107/s1600576724001730","DOIUrl":"https://doi.org/10.1107/s1600576724001730","url":null,"abstract":"The strong metal–support interaction (SMSI) is a phenomenon observed in supported metal catalyst systems in which reducible metal oxide supports can form overlayers over the surface of active metal nanoparticles (NPs) under a hydrogen (H2) environment at elevated temperatures. SMSI has been shown to affect catalyst performance in many reactions by changing the type and number of active sites on the catalyst surface. Laboratory methods for the analysis of SMSI at the nanoparticle-ensemble level are lacking and mostly based on indirect evidence, such as gas chemisorption. Here, we demonstrate the possibility to detect and characterize SMSIs in Co/TiO\u0000 x\u0000 model catalysts using the laboratory X-ray standing wave (XSW) technique for a large ensemble of NPs at the bulk scale. We designed a thermally stable MoN\u0000 x\u0000 /SiN\u0000 x\u0000 periodic multilayer to retain XSW generation after reduction with H2 gas at 600°C. The model catalyst system was synthesized here by deposition of a thin TiO\u0000 x\u0000 layer on top of the periodic multilayer, followed by Co NP deposition via spare ablation. A partial encapsulation of Co NPs by TiO\u0000 x\u0000 was identified by analyzing the change in Ti atomic distribution. This novel methodological approach can be extended to observe surface restructuring of model catalysts in situ at high temperature (up to 1000°C) and pressure (≤3 mbar), and can also be relevant for fundamental studies in the thermal stability of membranes, as well as metallurgy.","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140360464","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}
Pub Date : 2024-03-31DOI: 10.1107/s1600576724002115
Valentin Munteanu, V. Starostin, Alessandro Greco, L. Pithan, A. Gerlach, A. Hinderhofer, Stefan Kowarik, Frank Schreiber
Due to the ambiguity related to the lack of phase information, determining the physical parameters of multilayer thin films from measured neutron and X-ray reflectivity curves is, on a fundamental level, an underdetermined inverse problem. This ambiguity poses limitations on standard neural networks, constraining the range and number of considered parameters in previous machine learning solutions. To overcome this challenge, a novel training procedure has been designed which incorporates dynamic prior boundaries for each physical parameter as additional inputs to the neural network. In this manner, the neural network can be trained simultaneously on all well-posed subintervals of a larger parameter space in which the inverse problem is underdetermined. During inference, users can flexibly input their own prior knowledge about the physical system to constrain the neural network prediction to distinct target subintervals in the parameter space. The effectiveness of the method is demonstrated in various scenarios, including multilayer structures with a box model parameterization and a physics-inspired special parameterization of the scattering length density profile for a multilayer structure. In contrast to previous methods, this approach scales favourably when increasing the complexity of the inverse problem, working properly even for a five-layer multilayer model and a periodic multilayer model with up to 17 open parameters.
由于缺乏相位信息，从测量的中子和 X 射线反射率曲线确定多层薄膜的物理参数从根本上说是一个未确定的逆问题。这种模糊性对标准神经网络造成了限制，制约了以往机器学习解决方案中考虑的参数范围和数量。为了克服这一挑战，我们设计了一种新颖的训练程序，将每个物理参数的动态先验边界作为神经网络的附加输入。通过这种方式，神经网络可以同时在逆问题未确定的更大参数空间的所有条件良好的子区间上进行训练。在推理过程中，用户可以灵活地输入自己关于物理系统的先验知识，将神经网络的预测限制在参数空间中不同的目标子区间。该方法在各种情况下都证明了其有效性，包括采用盒式模型参数化的多层结构，以及由物理学启发的多层结构散射长度密度剖面的特殊参数化。与以前的方法相比，这种方法在增加逆问题的复杂性时具有良好的扩展性，即使在五层多层模型和多达 17 个开放参数的周期性多层模型中也能正常工作。
{"title":"Neural network analysis of neutron and X-ray reflectivity data incorporating prior knowledge","authors":"Valentin Munteanu, V. Starostin, Alessandro Greco, L. Pithan, A. Gerlach, A. Hinderhofer, Stefan Kowarik, Frank Schreiber","doi":"10.1107/s1600576724002115","DOIUrl":"https://doi.org/10.1107/s1600576724002115","url":null,"abstract":"Due to the ambiguity related to the lack of phase information, determining the physical parameters of multilayer thin films from measured neutron and X-ray reflectivity curves is, on a fundamental level, an underdetermined inverse problem. This ambiguity poses limitations on standard neural networks, constraining the range and number of considered parameters in previous machine learning solutions. To overcome this challenge, a novel training procedure has been designed which incorporates dynamic prior boundaries for each physical parameter as additional inputs to the neural network. In this manner, the neural network can be trained simultaneously on all well-posed subintervals of a larger parameter space in which the inverse problem is underdetermined. During inference, users can flexibly input their own prior knowledge about the physical system to constrain the neural network prediction to distinct target subintervals in the parameter space. The effectiveness of the method is demonstrated in various scenarios, including multilayer structures with a box model parameterization and a physics-inspired special parameterization of the scattering length density profile for a multilayer structure. In contrast to previous methods, this approach scales favourably when increasing the complexity of the inverse problem, working properly even for a five-layer multilayer model and a periodic multilayer model with up to 17 open parameters.","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140358052","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}
Pub Date : 2024-03-31DOI: 10.1107/s1600576724001821
Ravi Raj Purohit Purushottam Raj Purohit, D. Fowan, Stephan Arnaud, Nils Blanc, J. Micha, René Guinebretière, O. Castelnau
X-ray Laue microdiffraction aims to characterize microstructural and mechanical fields in polycrystalline specimens at the sub-micrometre scale with a strain resolution of ∼10−4. Here, a new and unique Laue microdiffraction setup and alignment procedure is presented, allowing measurements at temperatures as high as 1500 K, with the objective to extend the technique for the study of crystalline phase transitions and associated strain-field evolution that occur at high temperatures. A method is provided to measure the real temperature encountered by the specimen, which can be critical for precise phase-transition studies, as well as a strategy to calibrate the setup geometry to account for the sample and furnace dilation using a standard α-alumina single crystal. A first application to phase transitions in a polycrystalline specimen of pure zirconia is provided as an illustrative example.
X 射线 Laue 微衍射旨在以 10-4 ∼ 10-4 的应变分辨率在亚微米尺度上表征多晶试样的微观结构和机械场。本文介绍了一种新颖独特的 Laue 微衍射装置和配准程序，可在高达 1500 K 的温度下进行测量，目的是将该技术扩展到研究高温下发生的晶体相变和相关应变场演变。该方法提供了一种测量试样遇到的实际温度的方法，这对于精确的相变研究至关重要，同时还提供了一种使用标准 α 氧化铝单晶校准装置几何形状的策略，以考虑试样和熔炉的扩张。作为示例，我们提供了纯氧化锆多晶试样相变的首次应用。
{"title":"Laue microdiffraction on polycrystalline samples above 1500 K achieved with the QMAX-µLaue furnace","authors":"Ravi Raj Purohit Purushottam Raj Purohit, D. Fowan, Stephan Arnaud, Nils Blanc, J. Micha, René Guinebretière, O. Castelnau","doi":"10.1107/s1600576724001821","DOIUrl":"https://doi.org/10.1107/s1600576724001821","url":null,"abstract":"X-ray Laue microdiffraction aims to characterize microstructural and mechanical fields in polycrystalline specimens at the sub-micrometre scale with a strain resolution of ∼10−4. Here, a new and unique Laue microdiffraction setup and alignment procedure is presented, allowing measurements at temperatures as high as 1500 K, with the objective to extend the technique for the study of crystalline phase transitions and associated strain-field evolution that occur at high temperatures. A method is provided to measure the real temperature encountered by the specimen, which can be critical for precise phase-transition studies, as well as a strategy to calibrate the setup geometry to account for the sample and furnace dilation using a standard α-alumina single crystal. A first application to phase transitions in a polycrystalline specimen of pure zirconia is provided as an illustrative example.","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140360802","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}
Pub Date : 2024-03-29DOI: 10.1107/s1600576724001997
William Chèvremont, Theyencheri Narayanan
This article describes a correction procedure for the removal of indirect background contributions to measured small-angle X-ray scattering patterns. The high scattering power of a sample in the ultra-small-angle region may serve as a secondary source for a window placed in front of the detector. The resulting secondary scattering appears as a sample-dependent background in the measured pattern that cannot be directly subtracted. This is an intricate problem in measurements at ultra-low angles, which can significantly reduce the useful dynamic range of detection. Two different procedures are presented to retrieve the real scattering profile of the sample.
本文介绍了一种校正程序，用于消除测量到的小角度 X 射线散射图案的间接背景贡献。样品在超小角区域的高散射能力可作为放置在探测器前的窗口的二次源。由此产生的二次散射在测量图案中显示为无法直接减去的样品相关背景。这是在超低角度测量中的一个复杂问题，会大大降低检测的有用动态范围。本文介绍了两种不同的程序来获取样品的真实散射曲线。
{"title":"A correction procedure for secondary scattering contributions from windows in small-angle X-ray scattering and ultra-small-angle X-ray scattering","authors":"William Chèvremont, Theyencheri Narayanan","doi":"10.1107/s1600576724001997","DOIUrl":"https://doi.org/10.1107/s1600576724001997","url":null,"abstract":"This article describes a correction procedure for the removal of indirect background contributions to measured small-angle X-ray scattering patterns. The high scattering power of a sample in the ultra-small-angle region may serve as a secondary source for a window placed in front of the detector. The resulting secondary scattering appears as a sample-dependent background in the measured pattern that cannot be directly subtracted. This is an intricate problem in measurements at ultra-low angles, which can significantly reduce the useful dynamic range of detection. Two different procedures are presented to retrieve the real scattering profile of the sample.","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140367184","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}
Pub Date : 2024-03-27DOI: 10.1107/s1600576724001523
Stachowski, T.R., Fischer, M.
{"title":"FLEXR GUI: a graphical user interface for multi-conformer modeling of proteins","authors":"Stachowski, T.R., Fischer, M.","doi":"10.1107/s1600576724001523","DOIUrl":"https://doi.org/10.1107/s1600576724001523","url":null,"abstract":"","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315995","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}
Pub Date : 2024-03-26DOI: 10.1107/s1600576724001717
Mueller-Dieckmann, C., Grinzato, A., Effantin, G., Fenel, D., Flot, D., Schoehn, G., Leonard, G., Kandiah, E.
{"title":"From solution to structure: empowering inclusive cryo-EM with a pre-characterization pipeline for biological samples","authors":"Mueller-Dieckmann, C., Grinzato, A., Effantin, G., Fenel, D., Flot, D., Schoehn, G., Leonard, G., Kandiah, E.","doi":"10.1107/s1600576724001717","DOIUrl":"https://doi.org/10.1107/s1600576724001717","url":null,"abstract":"","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315994","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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