Article
Chemistry, Physical
Chengwu Qiu, Yaroslav Odarchenko, Ines Lezcano-Gonzalez, Qingwei Meng, Tom Slater, Shaojun Xu, Andrew M. Beale
Summary: HAADF-STEM imaging and electron energy loss spectroscopy (EELS) were used to show that the presence of residual C12E4 surfactant on the surface of a TiO2 rutile support prevents the formation and migration of Ti3+/Ti2+ oxides and therefore TiO2-x. Additionally, the surfactant residues prevent the coalescence and aggregation of CoNPs during catalyst preparation, maintaining their dispersion and leading to a greater number of active Co species in the Co/TiO2 catalyst.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Lipeng Ding, Lv Zhao, Yaoyao Weng, Dominique Schryvers, Qing Liu, Hosni Idrissi
Summary: The heterogeneous precipitation of the eta phase on the E dispersoids of the 7075 aluminum alloy was investigated, revealing that the B particles are heterogeneously precipitated at the E particle interface, stabilizing the E/Al interface and increasing the drive force of heterogeneous precipitation.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Metallurgy & Metallurgical Engineering
Zhiwei Du, Yonggang Peng, Hang Teng, Zhong Cao, Kui Zhang, Minglong Ma, Xiaolei Han, Ting Li, Cong Che, Yongjun Li
Summary: Crystal structures, growth characteristics, and transformation of the precipitates in a Mg-7Gd-5Y-1Nd-2Zn-0.5Zr (wt.%) alloy aged at 200 degrees C were investigated. The study revealed the formation and development of solute clusters and various precipitates during aging, providing valuable insights into the aging behavior and performance of the alloy.
JOURNAL OF MAGNESIUM AND ALLOYS
(2023)
Article
Materials Science, Multidisciplinary
Shuai Dai, Huawei Zhang, Zeyu Bian, Jiwei Geng, Zhe Chen, Lei Wang, Mingliang Wang, Haowei Wang
Summary: The study provides insights into the recrystallized behavior and precipitation reaction of the in-situ nano TiB2/Al-Cu-Mg composite during heat treatment. Coefficient thermal expansion difference between TiB2 particles and Al matrix promotes the recrystallized behavior, while the strong pinning effect at recrystallized grain boundary induced by TiB2 is observed. The study also highlights the enhancement of precipitation kinetics by trace Mg and the continuous transformation of theta '' into theta' via atomic Cu rearrangement.
MATERIALS CHARACTERIZATION
(2021)
Article
Engineering, Electrical & Electronic
Huan Liu, Lei Xu, Lei Xiao, Chenchen Wu, Jing Wang, Junjie Qi
Summary: Determining the concentration and distribution of trace impurity is crucial in the manufacturing of advanced semiconductor materials and plays a significant role in the development of sophisticated electronics. This study utilized atomic resolution scanning transmission electron microscopy combined with EDS mapping to determine the two-dimensional distribution of Si-doped impurity in GaN. Furthermore, STEM image simulation was used to estimate the impurity distribution in the depth direction. This method has the potential to be helpful in determining trace impurity concentration and distribution in semiconductor materials.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Chemistry, Physical
Liliana P. L. Goncalves, Maria Meledina, Alexander Meledin, Dmitri Y. Petrovykh, Juliana P. S. Sousa, O. Salome G. P. Soares, Yury Kolen'ko, M. Fernando R. Pereira
Summary: N-doping is crucial for enhancing the catalytic performance of carbon nanotube-supported Ni catalysts for CO2 methanation. The N-doping improves the dispersion of Ni on the CNT support, leading to higher CO2 conversion and methane selectivity.
Article
Materials Science, Multidisciplinary
Zhiqiao Li, Xujun Su, Jingjing Chen, Lu Lu, Jun Huang, Lin Shi, Houwen Chen, Jinping Zhang, Jian-Feng Nie, Ke Xu
Summary: This study utilizes atomic-resolution scanning transmission electron microscopy and first-principles calculations to observe unconventional nano-sized hexagonal-shaped domains in AlN films. These domains consist of parallel stacking faults and exhibit unique assembled structures. The study also identifies the presence of partial dislocations at the corners of the domains and proposes a mechanism for their formation. The findings contribute to understanding the growth mechanism of the observed domains.
Article
Optics
Jake M. Charsley, Marius Rutkauskas, Yoann Altmann, Valentina Risdonne, Michela Botticelli, Margaret J. Smith, Christina R. T. Young, Derryck T. Reid
Summary: Spectrally-resolved imaging allows for the mapping of chemical composition by correlating spectroscopic features with specific molecular groups. We demonstrate a compressive hyperspectral imaging strategy that improves acquisition rate by acquiring data at 15% of the Nyquist rate. Experimental results show the potential of this method for non-destructive classification of cultural heritage.
Article
Chemistry, Multidisciplinary
Wei Wang, Wei Cai
Summary: A modern aberration-corrected STEM was used to study the motion of individual gold atoms on an amorphous carbon film. The tracked trajectories provided direct visualization of individual atoms' movements and quantified the number of tracked atoms in each frame. The observed behaviors of atoms were mainly dominated by the beam-induced motion.
Article
Nanoscience & Nanotechnology
Abhinandan Gangopadhyay, Chaomin Zhang, Aymeric Maros, Nikolai Faleev, Richard R. King, Christiana B. Honsberg, David J. Smith
Summary: The atomic-scale structure of extended defects in GaAs/GaAs1-xSbx/GaAs (001) heterostructures has been investigated using aberration-corrected scanning transmission electron microscopy. Two types of defects were identified: a dissociated screw dislocation or a partial dislocation dipole at the tensile-strained GaAs(cap)/GaAs0.34Sb0.66 interface, and a dissociated 90 degrees dislocation at the compressively-strained GaAs0.91Sb0.09/GaAs(substrate) interface. The intrinsic stacking faults associated with these defects were bounded by Shockley partial dislocations.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
S. L. Yang, X. J. Zhao, H. W. Chen, N. Wilson, J. F. Nie
Summary: The precipitates in an aged Al-Cu-Mg-Ag alloy were characterized using atomic-resolution EDXS STEM and HAADF STEM. A metastable precursor phase, Omega', with a hexagonal structure and a thickness of 0.915 nm, was found. The presence of Omega' reduces the energy barrier for the nucleation of Omega.
Article
Nanoscience & Nanotechnology
Zijian Yu, Yuanding Huang, Bin Peng, Ke Liu, Shubo Li, Wenbo Du
Summary: In-situ and ex-situ observations using high-angle annular dark-field scanning transmission electron microscopy reveal the formation mechanism of beta(1) phase in age-hardenable magnesium-rare earth alloys. The beta(1) phase is transformed from beta(F)' phase through short-range solute diffusion, atomic shuffle, and shear mechanism. This study provides direct evidence and resolves the long-standing controversy.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Yanhui Wang, Jianrong Gao, Lunhua He
Summary: Ni77Ga23 alloys were rapidly solidified and undercooled using glass fluxing treatment. The study indicates that rapid solidification leads to the formation of a disordered solid solution, and high undercoolings result in the formation of an equiaxed microstructure. Within the equiaxed grains, coherent cuboidal precipitates of Ni3Ga phase are dispersed, and HRTEM study reveals the presence of disordered nano-domains in the lattice of Ni3Ga phase.
SCRIPTA MATERIALIA
(2024)
Article
Nanoscience & Nanotechnology
Shiwei Pan, Chunan Li, Feng Qian, Longlong Hao, Yanjun Li
Summary: The detailed atomic structures of conservative {100} APBs within L12-Al3Zr particles forming at the early-stage of L12-D023 transition in an Al-Zr alloy were systematically studied by high angle annual dark-field scanning transmission electron microscope (HAADF-STEM). It is suggested that L12-D023 phase transition has been achieved through a diffusion mechanism, instead of shearing mechanism while the formation of APB is an intermediate stage of the phase transition process. First principles density functional theory (DFT) reveals that the formation of APBs and subsequent phase transition are energetically favorable, which provide the driving force for diffusion.
SCRIPTA MATERIALIA
(2023)
Article
Chemistry, Physical
Xin Hu, Lin Qi, Chaoqiang Liu, Houwen Chen, Xiaoyong Zhang, Hongge Yan, Kechao Zhou, Min Song
Summary: In this study, stacking faults within alpha '' martensite plates were investigated using advanced transmission electron microscopy and first-principles calculations. Two kinds of stacking faults were detected, and their formation mechanism was explained. These findings provide important insights into the martensitic transformation process from bcc-beta to orthorhombic-alpha '' phase.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Microscopy
C. Gao, C. Hofer, T. J. Pennycook
Summary: Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, contrast reversals can occur when the projected potential becomes strong. Recent research has shown that these reversals can be counteracted by adapting the focus. This study explains why the best contrast is often found with the probe focused to the middle of the sample and highlights the importance of convergence angle in thin samples to remove contrast reversals.
Article
Microscopy
J. Lindner, U. Ross, T. Meyer, V. Boureau, M. Seibt, Ch. Jooss
Summary: Phase-shifting electron holography is an excellent method with high phase sensitivity to reveal electron wave phase information. An advanced drift correction scheme is proposed in this study, which exploits the interface of the TEM specimen and the vacuum area in the hologram. This method allows for obtaining reliable phase information.
Article
Microscopy
Ali Jaberi, Nicolas Brodusch, Jun Song, Raynald Gauvin
Summary: This study investigates knock-on damage in lithium-ion batteries (LIBs) by computing threshold displacement energies (TDEs) and performing Monte Carlo simulation. The results indicate that Li is most sensitive to knock-on damage at moderate electron energies, and TDE is the principal parameter for assessing Li sensitivity to knock-on damage across similar structures.
Article
Microscopy
Alexander Schroeder, Christopher Rathje, Leon van Velzen, Maurits Kelder, Sascha Schaefer
Summary: This study utilizes novel event-based electron detector platforms to extend the temporal resolution of electron microscopy. By training a neural network to predict electron arrival time, the researchers were able to improve the timing accuracy and achieve a promising solution for enhancing electron timing precision in various electron microscopy applications.
Article
Microscopy
Avi Auslender, Nivedita Pandey, Amit Kohn, Oswaldo Dieguez
Summary: This article describes a faster implementation based on DFT for computing the mean inner potential of crystals, providing quantum-mechanical calculations beyond the independent-atom approximation. The study also reveals the dependence of the mean inner potential on sample boundary conditions, mass density, and magnetic susceptibility, highlighting its correlation with various material properties.
Article
Microscopy
Zhidong Yang, Dawei Zang, Hongjia Li, Zhao Zhang, Fa Zhang, Renmin Han
Summary: In this work, we propose a self-supervised deep learning model for cryo-ET volumetric image denoising based on noise modeling and sparsity guidance. Experimental results demonstrate that our method can achieve reliable denoising by training on single noisy volume and outperform existing methods.
Article
Microscopy
J. Kuttruff, J. Holder, Y. Meng, P. Baum
Summary: In this study, a robust clustering algorithm is proposed that can find clusters in a continuous stream of raw data in real time. This algorithm converts pixel hits measured by hybrid pixel detectors to real single-electron events. By continuously comparing with previous hits, the algorithm efficiently identifies the merging of new and old events.
Article
Microscopy
D. G. Senturk, C. P. Yu, A. De Backer, S. Van Aert
Summary: This article presents a statistics-based method for accurately counting the number of atoms in nanostructures, especially for images acquired with low electron doses and multiple element structures.
Article
Microscopy
Mauricio J. Prieto, Lucas de Souza Caldas, Liviu C. Tanase, Thomas Schmidt, Oscar Rodriguez de la Fuente
Summary: This study presents a synchrotron-based investigation of the synthesis process of a magnetite/hematite bilayer. Ion bombardment gradually transforms hematite into magnetite, and the growth of magnetite leads to the formation of stable boundaries. These findings are significant for understanding novel oxide heterostructures.
Article
Microscopy
Emre Yoruk, Holger Klein, Stephanie Kodjikian
Summary: Beam sensitive nanomaterials pose challenges for crystallographic structure determination. A dose symmetric electron diffraction tomography (DS-EDT) method is developed to reduce beam damage and obtain complete data sets by merging individual datasets from multiple crystals.
Article
Microscopy
A. Pofelski, Y. Zhu, G. A. Botton
Summary: The precision and sensitivity of the GPA method for strain characterization is a widely discussed topic. This study introduces the concept of phase noise and analyzes the parameter of sampling to improve the precision of GPA. Experimental and theoretical results demonstrate that using a larger pixel spacing in STEM can enhance the precision and sensitivity of the GPA method.
Article
Microscopy
Sangjun Kang, Di Wang, Christian Kuebel, Xiaoke Mu
Summary: Transmission electron microscopy is a valuable tool for assessing strain fields within materials. However, using thin specimens in TEM analysis can affect atomic configuration and deformation structure.