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المؤلفون: Jiameng Wang, Xingye Chen, Meng Ge, Yanhong Xu, Lihong Zhang, Yanyong Li
المصدر: Reaction Kinetics, Mechanisms and Catalysis. 130:241-256
مصطلحات موضوعية: Materials science, 010405 organic chemistry, Oxide, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Propene, chemistry.chemical_compound, chemistry, Chemical engineering, Propane, Dehydrogenation, Physical and Theoretical Chemistry, Cobalt, Cobalt oxide, Incipient wetness impregnation
الوصف: This paper describes the synthesis and application of γ-Al2O3 supported SmCoO3 perovskite-type oxide in the catalytic propane dehydrogenation to propene. Various techniques including X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), transmission electron microscopy (TEM), thermogravimetric analysis (TG) and X-ray photoelectron spectra (XPS) were used to characterize the physico-chemical properties of SmCoO3/Al2O3 and derived Co-based catalyst. The characterization results reveal that the perovskite lattice confinement can lead to better dispersed cobalt oxide and restrain the reduction to metallic Co species. Under the high weight hourly space velocity (3 h−1), the propane conversion and propene selectivity of the reduced SmCoO3/Al2O3 catalyst were 25% and 94%, respectively, and obviously higher than those of the reduced SmCoO/Al2O3 catalyst used as a referential sample prepared by an incipient wetness impregnation method. A large amount of coke was formed over the used SmCoO/Al2O3 catalyst. Instead, the SmCoO3/Al2O3-derived Co-based catalyst can greatly reduce the amount of coke deposition. The superior catalytic performance and anti-coking ability of SmCoO3/Al2O3 catalyst are attributed to the formation of a large amount of well-dispersed surface Co2+ species, especially small CoO nanoparticles, and the absence of metallic Co species.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::6ebb75b07aace858fba5b98a9015afaa
https://doi.org/10.1007/s11144-020-01779-8 -
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المؤلفون: Juntao Gao, Xingye Chen, Miaoyan Wang, Xusan Yang, Long Chen, Peng Xi, Chao He
المصدر: Computational and Structural Biotechnology Journal
Computational and Structural Biotechnology Journal, Vol 18, Iss, Pp 2209-2216 (2020)مصطلحات موضوعية: Diffraction, Materials science, lcsh:Biotechnology, Biophysics, Review Article, Biochemistry, Molecular organization, 03 medical and health sciences, 0302 clinical medicine, Optics, Dipole orientation, Structural Biology, lcsh:TP248.13-248.65, Microscopy, Genetics, Molecule, 030304 developmental biology, 0303 health sciences, business.industry, Biomolecule interactions, Polarization (waves), Superresolution, Fluorescence, Computer Science Applications, Dipole, Super-resolution, 030220 oncology & carcinogenesis, business, Fluorescence anisotropy, Fluorescence polarization microscopy, Biotechnology
الوصف: Fluorescence polarization microscopy (FPM) analyzes both intensity and orientation of fluorescence dipole, and reflects the structural specificity of target molecules. It has become an important tool for studying protein organization, orientational order, and structural changes in cells. However, suffering from optical diffraction limit, conventional FPM has low orientation resolution and observation accuracy, as the polarization information is averaged by multiple fluorescent molecules within a diffraction-limited volume. Recently, novel super-resolution FPMs have been developed to break the diffraction barrier. In this review, we will introduce the recent progress to achieve sub-diffraction determination of dipole orientation. Biological applications, based on polarization analysis of fluorescence dipole, are also summarized, with focus on chromophore-target molecule interaction and molecular organization.
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المؤلفون: Jiameng Wang, Xingye Chen, Meng Ge, Yatian Liu, Lihong Zhang, Yanyong Li
المصدر: Applied Surface Science. 490:611-621
مصطلحات موضوعية: Materials science, General Physics and Astronomy, Nanoparticle, 02 engineering and technology, Surfaces and Interfaces, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Catalysis, Propene, chemistry.chemical_compound, chemistry, Chemical engineering, X-ray photoelectron spectroscopy, Propane, Interstitial defect, Dehydrogenation, 0210 nano-technology, Bimetallic strip
الوصف: A series of novel γ-Al2O3 supported Pt In bimetallic catalysts were prepared by perovskite (PTO) lattice interstitial confined reduction and compared with industrial catalyst PtIn/γ-Al2O3 in the propane dehydrogenation to propene. The physics-chemistry properties of all catalysts and precursors were characterized by BET, NH3-TPD, TPR, XRD, TEM, STEM-EDS, XPS, TG and O2-TPO techniques. The results show that the metal ions of Pt4+ and In3+ confined in PTO lattice interstitial sites were more easily reduced than those confined in PTO lattice. The lattice interstitial confinement was beneficial for the formation of small and highly dispersed Pt In bimetallic species on the surface of γ-Al2O3 supported PTO Nano islands. It is just the confinement of PTO lattice interstitial sites for appropriate In3+/In0 ratio and weak Pt In interaction and the sharing Al O bond for anchoring PTO nanoparticles and weakening the surface acid sites result in the high activity and superior stability of PtIn/LaAlO3/γ-Al2O3 in propane dehydrogenation. The initial propane conversion of PtIn/LaAlO3/γ-Al2O3 was 47%, and can be maintained at 25% after 16 h, while its propene selectivity only decreased from 96% to 90%.
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المؤلفون: Meiqi Li, Sha Luo, Dayong Jin, Karl Zhanghao, Hao Xie, Yiming Wang, Xiao Wang, Juntao Gao, Peng Xi, Qionghai Dai, Chunyan Shan, Xiangdong Li, Yiqiong Liu, Wenhui Liu, Xiaowei Chen, Xingye Chen, Yan Zhang
المصدر: Nature Communications
Nature Communications, Vol 10, Iss 1, Pp 1-10 (2019)مصطلحات موضوعية: 0301 basic medicine, Materials science, Science, General Physics and Astronomy, Myosins, Kidney, Hippocampus, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Quantitative Biology::Cell Behavior, law.invention, Quantitative Biology::Subcellular Processes, 010309 optics, Mice, 03 medical and health sciences, Optics, Live cell imaging, law, Cell Line, Tumor, 0103 physical sciences, Microscopy, Animals, Humans, Super-resolution microscopy, lcsh:Science, Cytoskeleton, Neurons, Multidisciplinary, business.industry, Resolution (electron density), Polarization Microscopy, DNA, General Chemistry, Laser, Bacteriophage lambda, Fluorescence, Actins, Dipole, 030104 developmental biology, Microscopy, Fluorescence, Polarization microscopy, lcsh:Q, Microscopy, Polarization, business
الوصف: Fluorescence polarization microscopy images both the intensity and orientation of fluorescent dipoles and plays a vital role in studying molecular structures and dynamics of bio-complexes. However, current techniques remain difficult to resolve the dipole assemblies on subcellular structures and their dynamics in living cells at super-resolution level. Here we report polarized structured illumination microscopy (pSIM), which achieves super-resolution imaging of dipoles by interpreting the dipoles in spatio-angular hyperspace. We demonstrate the application of pSIM on a series of biological filamentous systems, such as cytoskeleton networks and λ-DNA, and report the dynamics of short actin sliding across a myosin-coated surface. Further, pSIM reveals the side-by-side organization of the actin ring structures in the membrane-associated periodic skeleton of hippocampal neurons and images the dipole dynamics of green fluorescent protein-labeled microtubules in live U2OS cells. pSIM applies directly to a large variety of commercial and home-built SIM systems with various imaging modality.
Polarization microscopy has been combined with single-molecule localization, but it’s often limited in either speed or resolution. Here the authors present polarized Structured Illumination Microscopy (pSIM), a method that uses polarized laser excitation to measure dye orientation during fast super-resolution live cell imaging. -
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المؤلفون: Haoqian Wang, Chunyan Shan, Meiqi Li, Peng Xi, Wenhui Liu, Xingye Chen, Karl Zhanghao, Qionghai Dai
مصطلحات موضوعية: Dipole, Accuracy and precision, Optics, Materials science, Optical sectioning, business.industry, Confocal, Optical transfer function, Microscopy, business, Polarization (waves), Fluorescence
الوصف: The orientation and wobbling behavior of the fluorescent dipoles are of great significance in revealing the structure and state of cells. Due to the poor optical sectioning capability of wide-field microscopy, the polarization modulation signals are susceptible to the neighboring fluorophores. The missing cone of wide field optical transfer function induces vast out-of-focus background, resulting in biased polarization orientation and decrease polarization factor. Here, we apply polarized structured illumination to achieve polarization modulation imaging with optical sectioning, and simultaneously measure the lipid polarity with two-color ratiometric imaging. Our results demonstrate a significant increase in measurement accuracy of not only the dipole orientations but also the wobbling behavior of the ensemble dipole. Compared to the conventional confocal polarization imaging, our method obtains an order-of-magnitude faster imaging speed, capturing the fast dynamics of subcellular structures in live cells.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::894d6669afc19f62fc6bf303c1020f04
https://doi.org/10.1101/640268 -
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المؤلفون: G. Y. Shi, Yiming Sun, Fangsen Li, Xingye Chen, Jia Zhang, Feng Pan, Yunfeng You, Cheng Song, Xiaofeng Zhou, M. S. Saleem
المصدر: Physical Review Applied. 11
مصطلحات موضوعية: Materials science, Condensed matter physics, Spintronics, General Physics and Astronomy, Heterojunction, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, 0103 physical sciences, Moment (physics), Torque, Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology, Spin (physics), Realization (systems), Single layer
الوصف: Efficient electrical switching of antiferromagnets (AFMs) is key to their use in high-density, ultrafast, nonvolatile spintronic memory. Mn${}_{2}$Au, an AFM with opposite spin sublattices, is a unique metallic material, in that fieldlike spin torque can switch its AFM moments. However, switching induced by antidamping torque remains to be verified in metallic AFMs. Here the authors demonstrate current-induced switching of AFM moment in both a (103)-oriented Mn${}_{2}$Au single layer and a Mn${}_{2}$Au/Pt heterojunction by fieldlike torque and antidamping torque respectively. The simultaneous realization of both torque types in metallic Mn2Au makes it a promising candidate for AFM spintronics.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::3b6cee80b4a4e43f817b8e197d9480cd
https://doi.org/10.1103/physrevapplied.11.054030 -
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المؤلفون: Fangsen Li, Xingye Chen, Xiaofeng Zhou, Cheng Song, Y. Z. Tan, Lichen Yin, Feng Pan, Hua-Kun Liu, Yiming Sun, Yunfeng You
المصدر: Physical Review Applied. 11
مصطلحات موضوعية: Phase transition, Materials science, Condensed matter physics, General Physics and Astronomy, Semiconductor memory, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Non-volatile memory, Matrix (mathematics), Ferromagnetism, Phase (matter), 0103 physical sciences, Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology, Anisotropy
الوصف: Current-driven domain-wall motion has attracted intense attention, due to its rich physics and promising application in ``racetrack'' nonvolatile memory. However, the interplay between antiferromagnetic/ferromagnetic (AFM/FM) phase boundaries and current has remained elusive. To investigate, the authors use pulses of current to induce the formation of anisotropic FM domains in an AFM matrix. The phase boundaries can be reversibly oriented by the applied (writing) current, giving rise to the orthogonal alignment of phase boundaries and current, which could pave the way for multistage digital memory based on AFM/FM boundaries.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::50ee6dee7617d061099c38182a106849
https://doi.org/10.1103/physrevapplied.11.024021 -
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المؤلفون: Xingye Chen, Feng Pan, Y. J. Zhou, Xisong Zhou, Ruyi Chen, Hailin Bai, Cheng Song
المصدر: Journal of Applied Physics. 127:163904
مصطلحات موضوعية: 010302 applied physics, Materials science, Condensed matter physics, Magnetoresistance, Spintronics, Bilayer, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Ferrimagnetism, 0103 physical sciences, Antiferromagnetism, 0210 nano-technology, Spin (physics)
الوصف: Spin Hall magnetoresistance (SMR) provides a unique opportunity for the signal readout of magnetic ordering, especially for magnetic insulators. However, the magnitude of SMR signals is quite small, generally lower than one in a thousand, which is a persistent challenge in the field of spintronics. Here, we investigate SMR at room temperature in α-Fe2O3/Pt and γ-Fe2O3/Pt bilayers as well as the α-Fe2O3/Pt/γ-Fe2O3 trilayer, where α-Fe2O3 and γ-Fe2O3 are antiferromagnetic and ferrimagnetic materials, respectively. In contrast to the positive SMR in the γ-Fe2O3/Pt bilayer, an unprecedentedly large negative SMR with the magnitude of ∼0.35% is observed in the α-Fe2O3/Pt bilayer due to the spin-flop. The α-Fe2O3/Pt/γ-Fe2O3 trilayer shows features of a combination of positive and negative SMR. A comparative study of SMR in the Fe2O3 family not only enriches spin physics, but also makes Fe2O3 a versatile candidate in spintronic devices.
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المؤلفون: Youdi Gu, G. Y. Shi, H. Q. Wu, M. S. Saleem, Fangsen Li, Xiaofeng Zhou, Cheng Song, Feng Pan, Y. Z. Tan, Jia Zhang, Xingye Chen
المصدر: Physical Review Applied. 9
مصطلحات موضوعية: Materials science, Magnetic moment, Spintronics, Condensed matter physics, Alloy, General Physics and Astronomy, 02 engineering and technology, engineering.material, 021001 nanoscience & nanotechnology, 01 natural sciences, Condensed Matter::Materials Science, 0103 physical sciences, Moment (physics), engineering, Antiferromagnetism, Torque, Condensed Matter::Strongly Correlated Electrons, Strong orientation, Thin film, 010306 general physics, 0210 nano-technology
الوصف: With zero net magnetic moment for ultrafast switching and high resistance to interference, antiferromagnets are of keen interest for next-generation data storage. This study demonstrates and analyzes current-induced switching of antiferromagnetic moment in Mn${}_{2}$Au films at room temperature, with different film orientations exhibiting various switching characteristics. This strong orientation dependence of switching adds another dimension to our thinking about spin-orbit torque, and makes this alloy a versatile basis for antiferromagnetic spintronics.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::04bf5102ab1d138d12b8ff595079cf3e
https://doi.org/10.1103/physrevapplied.9.054028 -
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المؤلفون: G. Y. Shi, Can-Li Song, Xingye Chen, Feng Pan, Pengxiang Zhang, Xuesi Zhou
المصدر: 2018 IEEE International Magnetics Conference (INTERMAG).
مصطلحات موضوعية: Switching time, Magnetization, Magnetic anisotropy, Materials science, Condensed matter physics, Ferromagnetism, Magnetic moment, Demagnetizing field, Antiferromagnetism, Magnetocrystalline anisotropy
الوصف: Antiferromagnets with zero net magnetic moment, strong anti-interference and ultrafast switching speed have potential competitiveness in high-density information storage [1], [2]. Electrical switching of antiferromagnets is at the heart of device application [3]. We will present our recent progress in the current-driven magnetization switching through spin-orbit torque (SOT) in three antiferromagnetic systems, including Mn 2 Au, and [Co/Pd]/Ru/[Co/Pd] synthetic antiferromagnets (SAF). Body centered tetragonal antiferromagnet Mn 2 Au with opposite spin sub-lattices is a unique metallic material for Neelorder spin-orbit torque (SOT) switching. The SOT switching in quasi-epitaxial (103), (101) and (204) Mn 2 Au films prepared by a simple magnetron sputtering method will be discussed. We demonstrate current induced antiferromagnetic moment switching in all the prepared Mn 2 Au films by a short current pulse at room temperature, whereas different orientated films exhibit distinguished switching characters. A direction-independent reversible switching is attained in Mn 2 Au (103) films due to negligible magnetocrystalline anisotropy energy, while for Mn 2 Au (101) and (204) films, the switching is invertible with the current applied along the in-plane easy axis and its vertical axis, but becomes attenuated seriously during initially switching circles when the current is applied along hard axis, because of the existence of magnetocrystalline anisotropy energy [4]. SAF were proposed to replace ferromagnets in magnetic memory devices to reduce the stray field, increase the storage density and improve the thermal stability. We will discuss the SOT in a perpendicularly magnetized Pt/[Co/Pd]/Ru/[Co/ Pd] SAF structure, which exhibits completely compensated magnetization and a high exchange coupling field of 2200 Oe. The magnetizations of two Co/Pd layers can be switched by spin-orbit torque between two antiparallel states simultaneously. The magnetization switching can be read out due to much stronger spin-orbit coupling at bottom Pt/[Co/Pd] interface compared to its upper counterpart without Pt. Both experimental and theoretical analyses unravel that the torque efficiency of antiferromagnetic coupled stacks is significantly higher than the ferromagnetic counterpart, which conquers the exchange coupling field, leading to the critical switching current of SAF comparable to the ferromagnetic coupled one [5], [6]. Besides the fundamental significance, the efficient switching of antiferromagnets by current would advance magnetic memory devices with high density, high speed and low power consumption.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::0944ec6948e160dfe01e030d9e1a8dda
https://doi.org/10.1109/intmag.2018.8508149
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