Advanced Structural and Chemical Imaging最新文献_第5页

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Advanced Structural and Chemical Imaging Pub Date : 2016-12-01 DOI: 10.1186/s40679-016-0029-7

Zdeněk Matěj, Rajmund Mokso, Krister Larsson, Vincent Hardion, Darren Spruce

引用次数: 2

Automatic software correction of residual aberrations in reconstructed HRTEM exit waves of crystalline samples 晶体样品HRTEM出口重构波残差的自动软件校正

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-11-30 DOI: 10.1186/s40679-016-0030-1

Colin Ophus, Haider I Rasool, Martin Linck, Alex Zettl, Jim Ciston

引用次数: 16

Identifying local structural states in atomic imaging by computer vision 利用计算机视觉识别原子成像中的局部结构状态

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-11-02 DOI: 10.1186/s40679-016-0028-8

Nouamane Laanait, Maxim Ziatdinov, Qian He, Albina Borisevich

{"title":"Identifying local structural states in atomic imaging by computer vision","authors":"Nouamane Laanait, Maxim Ziatdinov, Qian He, Albina Borisevich","doi":"10.1186/s40679-016-0028-8","DOIUrl":"https://doi.org/10.1186/s40679-016-0028-8","url":null,"abstract":"The availability of atomically resolved imaging modalities enables an unprecedented view into the local structural states of materials, which manifest themselves by deviations from the fundamental assumptions of periodicity and symmetry. Consequently, approaches that aim to extract these local structural states from atomic imaging data with minimal assumptions regarding the average crystallographic configuration of a material are indispensable to advances in structural and chemical investigations of materials. Here, we present an approach to identify and classify local structural states that is rooted in computer vision. This approach introduces a definition of a structural state that is composed of both local and nonlocal information extracted from atomically resolved images, and is wholly untethered from the familiar concepts of symmetry and periodicity. Instead, this approach relies on computer vision techniques such as feature detection, and concepts such as scale invariance. We present the fundamental aspects of local structural state extraction and classification by application to simulated scanning transmission electron microscopy images, and analyze the robustness of this approach in the presence of common instrumental factors such as noise, limited spatial resolution, and weak contrast. Finally, we apply this computer vision-based approach for the unsupervised detection and classification of local structural states in an experimental electron micrograph of a complex oxides interface, and a scanning tunneling micrograph of a defect-engineered multilayer graphene surface.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0028-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4099396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Detecting structural variances of Co3O4 catalysts by controlling beam-induced sample alterations in the vacuum of a transmission electron microscope 通过在真空透射电子显微镜下控制光束诱导的样品变化来检测Co3O4催化剂的结构差异

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-11-02 DOI: 10.1186/s40679-016-0027-9

C. Kisielowski, H. Frei, P. Specht, I. D. Sharp, J. A. Haber, S. Helveg

{"title":"Detecting structural variances of Co3O4 catalysts by controlling beam-induced sample alterations in the vacuum of a transmission electron microscope","authors":"C. Kisielowski, H. Frei, P. Specht, I. D. Sharp, J. A. Haber, S. Helveg","doi":"10.1186/s40679-016-0027-9","DOIUrl":"https://doi.org/10.1186/s40679-016-0027-9","url":null,"abstract":"This article summarizes core aspects of beam-sample interactions in research that aims at exploiting the ability to detect single atoms at atomic resolution by mid-voltage transmission electron microscopy. Investigating the atomic structure of catalytic Co3O4 nanocrystals underscores how indispensable it is to rigorously control electron dose rates and total doses to understand native material properties on this scale. We apply in-line holography with variable dose rates to achieve this goal. Genuine object structures can be maintained if dose rates below?~100 e/?2s are used and the contrast required for detection of single atoms is generated by capturing large image series. Threshold doses for the detection of single atoms are estimated. An increase of electron dose rates and total doses to common values for high resolution imaging of solids stimulates object excitations that restructure surfaces, interfaces, and defects and cause grain reorientation or growth. We observe a variety of previously unknown atom configurations in surface proximity of the Co3O4 spinel structure. These are hidden behind broadened diffraction patterns in reciprocal space but become visible in real space by solving the phase problem. An exposure of the Co3O4 spinel structure to water vapor or other gases induces drastic structure alterations that can be captured in this manner.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0027-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4099698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Structural damage reduction in protected gold clusters by electron diffraction methods 用电子衍射方法降低受保护金团簇的结构损伤

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-09-26 DOI: 10.1186/s40679-016-0026-x

Eduardo Ortega, Arturo Ponce, Ulises Santiago, Diego Alducin, Alfredo Benitez-Lara, Germán Plascencia-Villa, Miguel José-Yacamán

{"title":"Structural damage reduction in protected gold clusters by electron diffraction methods","authors":"Eduardo Ortega, Arturo Ponce, Ulises Santiago, Diego Alducin, Alfredo Benitez-Lara, Germán Plascencia-Villa, Miguel José-Yacamán","doi":"10.1186/s40679-016-0026-x","DOIUrl":"https://doi.org/10.1186/s40679-016-0026-x","url":null,"abstract":"The present work explores electron diffraction methods for studying the structure of metallic clusters stabilized with thiol groups, which are susceptible to structural damage caused by electron beam irradiation. There is a compromise between the electron dose used and the size of the clusters since they have small interaction volume with electrons and as a consequence weak reflections in the diffraction patterns. The common approach of recording individual clusters using nanobeam diffraction has the problem of an increased current density. Dosage can be reduced with the use of a smaller condenser aperture and a higher condenser lens excitation, but even with those set ups collection times tend to be high. For that reason, the methods reported herein collects in a faster way diffraction patterns through the scanning across the clusters under nanobeam diffraction mode. In this way, we are able to collect a map of diffraction patterns, in areas with dispersed clusters, with short exposure times (milliseconds) using a high sensitive CMOS camera. When these maps are compared with their theoretical counterparts, oscillations of the clusters can be observed. The stability of the patterns acquired demonstrates that our methods provide a systematic and precise way to unveil the structure of atomic clusters without extensive detrimental damage of their crystallinity.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0026-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5022131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images 利用级偏置电位对探测光束进行减速，提高了连续块面扫描电镜图像的分辨率

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-09-15 DOI: 10.1186/s40679-016-0025-y

James C. Bouwer, Thomas J. Deerinck, Eric Bushong, Vadim Astakhov, Ranjan Ramachandra, Steven T. Peltier, Mark H. Ellisman

{"title":"Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images","authors":"James C. Bouwer, Thomas J. Deerinck, Eric Bushong, Vadim Astakhov, Ranjan Ramachandra, Steven T. Peltier, Mark H. Ellisman","doi":"10.1186/s40679-016-0025-y","DOIUrl":"https://doi.org/10.1186/s40679-016-0025-y","url":null,"abstract":"Serial block-face scanning electron microscopy (SBEM) is quickly becoming an important imaging tool to explore three-dimensional biological structure across spatial scales. At probe-beam-electron energies of 2.0?keV or lower, the axial resolution should improve, because there is less primary electron penetration into the block face. More specifically, at these lower energies, the interaction volume is much smaller, and therefore, surface detail is more highly resolved. However, the backscattered electron yield for metal contrast agents and the backscattered electron detector sensitivity are both sub-optimal at these lower energies, thus negating the gain in axial resolution. We found that the application of a negative voltage (reversal potential) applied to a modified SBEM stage creates a tunable electric field at the sample. This field can be used to decrease the probe-beam-landing energy and, at the same time, alter the trajectory of the signal to increase the signal collected by the detector. With decelerated low landing-energy electrons, we observed that the probe-beam-electron-penetration depth was reduced to less than 30?nm in epoxy-embedded biological specimens. Concurrently, a large increase in recorded signal occurred due to the re-acceleration of BSEs in the bias field towards the objective pole piece where the detector is located. By tuning the bias field, we were able to manipulate the trajectories of the ?primary and secondary electrons, enabling the spatial discrimination of these signals using an advanced?ring-type BSE detector configuration or a standard monolithic BSE detector coupled with a blocking aperture.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0025-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4631528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 26

HRTEM low dose: the unfold of the morphed graphene, from amorphous carbon to morphed graphenes 低剂量HRTEM:变形石墨烯的展开，从无定形碳到变形石墨烯

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-08-22 DOI: 10.1186/s40679-016-0024-z

H. A. Calderon, A. Okonkwo, I. Estrada-Guel, V. G. Hadjiev, F. Alvarez-Ramírez, F. C. Robles Hernández

{"title":"HRTEM low dose: the unfold of the morphed graphene, from amorphous carbon to morphed graphenes","authors":"H. A. Calderon, A. Okonkwo, I. Estrada-Guel, V. G. Hadjiev, F. Alvarez-Ramírez, F. C. Robles Hernández","doi":"10.1186/s40679-016-0024-z","DOIUrl":"https://doi.org/10.1186/s40679-016-0024-z","url":null,"abstract":"We present experimental evidence under low-dose conditions transmission electron microscopy for the unfolding of the evolving changes in carbon soot during mechanical milling. The\u0000 milled soot shows evolving changes as a function of the milling severity or time. Those changes are responsible for the transformation from amorphous carbon to graphenes, graphitic carbon, and highly ordered structures such as morphed graphenes, namely Rh6 and Rh6-II. The morphed graphenes are corrugated layers of carbon with cross-linked covalently nature and sp2- or sp3-type allotropes. Electron microscopy and numerical simulations are excellent complementary tools to identify those phases. Furthermore, the TEAM 05 microscope is an outstanding tool to resolve the microstructure and prevent any damage to the sample. Other characterization techniques such as XRD, Raman, and XPS fade to convey a true identification of those phases because the samples are usually blends or mixes of the mentioned phases.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0024-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4847776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 31

Growth of dendritic nanostructures by liquid-cell transmission electron microscopy: a reflection of the electron-irradiation history 液相细胞透射电子显微镜生长树枝状纳米结构：电子辐照历史的反映

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-06-30 DOI: 10.1186/s40679-016-0023-0

Nabeel Ahmad, Yann Le Bouar, Christian Ricolleau, Damien Alloyeau

{"title":"Growth of dendritic nanostructures by liquid-cell transmission electron microscopy: a reflection of the electron-irradiation history","authors":"Nabeel Ahmad, Yann Le Bouar, Christian Ricolleau, Damien Alloyeau","doi":"10.1186/s40679-016-0023-0","DOIUrl":"https://doi.org/10.1186/s40679-016-0023-0","url":null,"abstract":"Studying dynamical processes by transmission electron microscopy (TEM) requires considering the electron-irradiation history, including the instantaneous dose rate and the cumulative dose delivered to the sample. Here, we have exploited liquid-cell TEM to study the effects of the electron-irradiation history on the radiochemical growth of dendritic Au nanostructures. Besides the well-established direct link between the dose rate and the growth rate of the nanostructures, we demonstrate that the cumulative dose in the irradiated area can also induce important transitions in the growth mode of the nanostructures. By comparing in situ observations with an extended diffusion-limited aggregation model, we reveal how the shape of the nanostructures is severely affected by the local lack of metal precursors and the resulting restricted accessibility of gold atoms to the nanostructures. This study highlights the effects of electron irradiation on the solution chemistry in the irradiated area and in the whole liquid cell that are of primary importance to extract quantitative information on nanoscale processes.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0023-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5156416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19

3D reconstruction of biological structures: automated procedures for alignment and reconstruction of multiple tilt series in electron tomography 生物结构的三维重建:电子断层扫描中多重倾斜序列对齐和重建的自动化程序

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-06-28 DOI: 10.1186/s40679-016-0021-2

Sébastien Phan, Daniela Boassa, Phuong Nguyen, Xiaohua Wan, Jason Lanman, Albert Lawrence, Mark H. Ellisman

{"title":"3D reconstruction of biological structures: automated procedures for alignment and reconstruction of multiple tilt series in electron tomography","authors":"Sébastien Phan, Daniela Boassa, Phuong Nguyen, Xiaohua Wan, Jason Lanman, Albert Lawrence, Mark H. Ellisman","doi":"10.1186/s40679-016-0021-2","DOIUrl":"https://doi.org/10.1186/s40679-016-0021-2","url":null,"abstract":"Transmission electron microscopy allows the collection of multiple views of specimens and their computerized three-dimensional reconstruction and analysis with electron tomography. Here we describe development of methods for automated multi-tilt data acquisition, tilt-series processing, and alignment which allow assembly of electron tomographic data from a greater number of tilt series, yielding enhanced data quality and increasing contrast associated with weakly stained structures. This scheme facilitates visualization of nanometer scale details of fine structure in volumes taken from plastic-embedded samples of biological specimens in all dimensions. As heavy metal-contrasted plastic-embedded samples are less sensitive to the overall dose rather than the electron dose rate, an optimal resampling of the reconstruction space can be achieved by accumulating lower dose electron micrographs of the same area over a wider range of specimen orientations. The computerized multiple tilt series collection scheme is implemented together with automated advanced procedures making collection, image alignment, and processing of multi-tilt tomography data a seamless process. We demonstrate high-quality reconstructions from samples of well-described biological structures. These include the giant Mimivirus and clathrin-coated vesicles, imaged in situ in their normal intracellular contexts. Examples are provided from samples of cultured cells prepared by high-pressure freezing and freeze-substitution as well as by chemical fixation before epoxy resin embedding.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0021-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5085032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 38

Electron beam induced dehydrogenation of MgH2 studied by VEELS 电子束诱导MgH2脱氢的研究

IF 3.56

Advanced Structural and Chemical Imaging Pub Date : 2016-06-23 DOI: 10.1186/s40679-016-0022-1

Alexander Surrey, Ludwig Schultz, Bernd Rellinghaus

{"title":"Electron beam induced dehydrogenation of MgH2 studied by VEELS","authors":"Alexander Surrey, Ludwig Schultz, Bernd Rellinghaus","doi":"10.1186/s40679-016-0022-1","DOIUrl":"https://doi.org/10.1186/s40679-016-0022-1","url":null,"abstract":"Nanosized or nanoconfined hydrides are promising materials for solid-state hydrogen storage. Most of these hydrides, however, degrade fast during the structural characterization utilizing transmission electron microscopy (TEM) upon the irradiation with the imaging electron beam due to radiolysis. We use ball-milled MgH2 as a reference material for in-situ TEM experiments under low-dose conditions to study and quantitatively understand the electron beam-induced dehydrogenation. For this, valence electron energy loss spectroscopy (VEELS) measurements are conducted in a monochromated FEI Titan3 80–300 microscope. From observing the plasmonic absorptions it is found that MgH2 successively converts into Mg upon electron irradiation. The temporal evolution of the spectra is analyzed quantitatively to determine the thickness-dependent, characteristic electron doses for electron energies of both 80 and 300 keV. The measured electron doses can be quantitatively explained by the inelastic scattering of the incident high-energy electrons by the MgH2 plasmon. The obtained insights are also relevant for the TEM characterization of other hydrides.","PeriodicalId":460,"journal":{"name":"Advanced Structural and Chemical Imaging","volume":"2 1","pages":""},"PeriodicalIF":3.56,"publicationDate":"2016-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40679-016-0022-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4901427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10