Journal of Applied Crystallography最新文献

{"title":"","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141251433","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":"Low-background ultrahigh-purity aluminium window for small-angle neutron scattering using monochromatic cold neutrons","authors":"Takayuki Kumada,&nbsp;Ryuhei Motokawa,&nbsp;Hiroki Iwase","doi":"10.1107/S160057672400373X","DOIUrl":"10.1107/S160057672400373X","url":null,"abstract":"<p>The 500 mm-diameter aluminium alloy neutron window in the SANS diffractometer SANS-J at JRR-3, Tokai, Japan, has been replaced by an ultrahigh-purity aluminium (5N-Al, &gt;99.999%) window. Although the 5N-Al window is three times thicker than the alloy window to compensate for the lower tensile strength, the background intensity in the small-angle neutron scattering (SANS) curve was successfully decreased by a factor of 10 at the maximum. The 5N-Al window is suitable not only for large-diameter neutron windows in SANS diffractometers but also for windows in their environmental apparatus which cannot be made of single-crystal silicon or other ceramics due to their poor availability, fracture strength, processability or affinity with metallic materials.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141126173","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":"","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141251505","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":"Program VUE: analysing distributions of cryo-EM projections using uniform spherical grids","authors":"L. Urzhumtseva, Charles Barchet, B. Klaholz, A. Urzhumtsev","doi":"10.1107/s1600576724002383","DOIUrl":"https://doi.org/10.1107/s1600576724002383","url":null,"abstract":"Three-dimensional cryo electron microscopy reconstructions are obtained by extracting information from a large number of projections of the object. These projections correspond to different `views' or `orientations', i.e. directions in which these projections show the reconstructed object. Uneven distribution of these views and the presence of dominating preferred orientations may distort the reconstructed spatial images. This work describes the program VUE (views on uniform grids for cryo electron microscopy), designed to study such distributions. Its algorithms, based on uniform virtual grids on a sphere, allow an easy calculation and accurate quantitative analysis of the frequency distribution of the views. The key computational element is the Lambert azimuthal equal-area projection of a spherical uniform grid onto a disc. This projection keeps the surface area constant and represents the frequency distribution with no visual bias. Since it has multiple tunable parameters, the program is easily adaptable to individual needs, and to the features of a particular project or of the figure to be produced. It can help identify problems related to an uneven distribution of views. Optionally, it can modify the list of projections, distributing the views more uniformly. The program can also be used as a teaching tool.","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140993611","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":"","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141251507","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":"The tin content of lead inclusions in ancient tin-bronze artifacts: a time-dependent process?","authors":"G. Artioli, A. Fontanari, I. Angelini, Chiara Lucarelli, M. Etter, Henrik Jeppesen, S. Shilstein, S. Shalev","doi":"10.1107/s1600576724002218","DOIUrl":"https://doi.org/10.1107/s1600576724002218","url":null,"abstract":"In antiquity, Pb was a common element added in the production of large bronze artifacts, especially large statues, to impart fluidity to the casting process. As Pb does not form a solid solution with pure Cu or with the Sn–Cu alloy phases, it is normally observed in the metal matrix as globular droplets embedded within or in interstitial positions among the crystals of Sn-bronze (normally the α phase) as the last crystallizing phase during the cooling process of the Cu–Sn–Pb ternary melt. The disequilibrium Sn content of the Pb droplets has recently been suggested as a viable parameter to detect modern materials [Shilstein, Berner, Feldman, Shalev & Rosenberg (2019). STAR Sci. Tech. Archaeol. Res. \u0000 5, 29–35]. The application assumes a time-dependent process, with a timescale of hundreds of years, estimated on the basis of the diffusion coefficient of Sn in Pb over a length of a few micrometres [Oberschmidt, Kim & Gupta (1982). J. Appl. Phys. \u0000 53, 5672–5677]. Therefore, Pb inclusions in recent Sn-bronze artifacts are actually a metastable solid solution of Pb–Sn containing ∼3% atomic Sn. In contrast, in ancient artifacts, unmixing processes and diffusion of Sn from the micro- and nano-inclusions of Pb to the matrix occur, resulting in the Pb inclusions containing a substantially lower or negligible amount of Sn. The Sn content in the Pb inclusions relies on accurate measurement of the lattice parameter of the phase in the Pb–Sn solid solution, since for low Sn values it closely follows Vegard's law. Here, several new measurements on modern and ancient samples are presented and discussed in order to verify the applicability of the method to the detection of modern artwork pretending to be ancient.","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140993457","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":"","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141251504","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":"","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141251508","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":"Novel high-efficiency 2D position-sensitive ZnS:Ag/6LiF scintillator detector for neutron diffraction","authors":"G. Mauri, G. J. Sykora, E. Schooneveld, S. C. Capelli, M. J. Gutmann, S. Howarth, S. Mann, F. Zuddas, N. J. Rhodes","doi":"10.1107/s1600576724002462","DOIUrl":"https://doi.org/10.1107/s1600576724002462","url":null,"abstract":"Scintillator-based ZnS:Ag/6LiF neutron detectors have been under development at ISIS for more than three decades. Continuous research and development aim to improve detector capabilities, achieve better performance and meet the increasingly demanding requirements set by neutron instruments. As part of this program, a high-efficiency 2D position-sensitive scintillator detector with wavelength-shifting fibres has been developed for neutron-diffraction applications. The detector consists of a double scintillator-fibre layer to improve detection efficiency. Each layer is made up of two orthogonal fibre planes placed between two ZnS:Ag/6LiF scintillator screens. Thin reflective foils are attached to the front and back scintillators of each layer to minimize light cross-talk between layers. The detector has an active area of 192 × 192 mm with a square pixel size of 3 × 3 mm. As part of the development process of the double-layer detector, a single-layer detector was built, together with a prototype detector in which the two layers of the detector could be read out separately. Efficiency calculations and measurements of all three detectors are discussed. The novel double-layer detector has been installed and tested on the SXD diffractometer at ISIS. The detector performance is compared with the current scintillator detectors employed on SXD by studying reference crystal samples. More than a factor of 3 improvement in efficiency is achieved with the double-layer wavelength-shifting-fibre detector. Software routines for further optimizations in spatial resolution and uniformity of response have been implemented and tested for 2D detectors. The methods and results are discussed in this manuscript.","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140990167","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":"High-pressure intrusion of double salt aqueous solution in pure silica chabazite: searching for cation selectivity","authors":"Giorgia Confalonieri,&nbsp;Andrey Ryzhikov,&nbsp;Rossella Arletti,&nbsp;Frederico Alabarse,&nbsp;Habiba Nouali,&nbsp;Riccardo Fantini,&nbsp;Jean Daou","doi":"10.1107/S1600576724002863","DOIUrl":"10.1107/S1600576724002863","url":null,"abstract":"<p>Heterogeneous lyophobic systems (HLSs), <i>i.e.</i> systems composed of a nanoporous solid and a non-wetting liquid, have attracted much attention as promising candidates for innovative mechanical energy storage and dissipation devices. In this work, a new HLS based on a pure silica chabazite (Si-CHA) and a ternary electrolyte solution (KCl + CaCl₂) is studied from porosimetric and crystallographic points of view. The combined approach of this study has been fundamental in unravelling the properties of the system. The porosimetric experiments allowed the determination of the energetic behaviour, while high-pressure <i>in situ</i> crystallographic analyses helped elucidate the mechanism of intrusion. The results are compared with those obtained for systems involving the same zeolite but intruded with solutions containing only single salts (CaCl₂ or KCl). The porosimetric results of the three Si-CHA systems intruded by simple and complex electrolyte solutions (KCl 2 <i>M</i>, CaCl₂ 2 <i>M</i> and the mixture KCl 1 <i>M</i> + CaCl₂ 1 <i>M</i>) suggest that the intrusion pressure is mainly influenced by the nature of the cations. The CaCl₂ 2 <i>M</i> solution shows the highest intrusion pressure and KCl 2 <i>M</i> the lowest, whereas the mixture KCl 1 <i>M</i> + CaCl₂ 1 <i>M</i> is almost in the middle. These differences are probably related to the higher hydration enthalpy and Gibbs energy of Ca²⁺ compared with those of K⁺. It has been demonstrated that partial ion desolvation is needed to promote the penetration of the species, and a higher solvation energy requires higher pressure. The `intermediate' value of intrusion pressure shown by the complex electrolyte solution arises from the fact that, statistically, the second/third solvation cation shells can be assumed to be partially shared between K⁺ and Ca²⁺. The stronger interaction of Ca²⁺ with H₂O molecules thus also influences the desolvation of K⁺, increasing the pressure needed to activate the process compared with the pure KCl 2 <i>M</i> solution. This is confirmed by the structural investigation, which shows that at the beginning of intrusion only K⁺, Cl⁻ and H₂O penetrate the pores, whereas the intrusion of Ca²⁺ requires higher pressure, in agreement with the hydration enthalpies of the two cations.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140993059","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}