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High-Throughput Electron Diffraction Reveals a Hidden Novel Metal–Organic Framework for Electrocatalysis

Angewandte Chemie 2021年第20期133卷

作者： Meng Ge Yanzhi Wang Francesco Carraro Weibin Liang Morteza Roostaeinia Samira Siahrostami Davide M. Proserpio Christian Doonan Paolo Falcaro Haoquan Zheng Xiaodong Zou Zhehao Huang Department of Materials and Environmental Chemistry Stockholm University 10691 Stockholm Sweden Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China Institute of Physical and Theoretical Chemistry Graz University of Technology Stremayrgasse 9 8010 Graz Austria Department of Chemistry and the Centre for Advanced Nanomaterials The University of Adelaide Adelaide 5005 South Australia Australia Department of Chemistry University of Calgary 2500 University Drive NW Calgary Alberta T2N1N4 Canada Dipartimento di Chimica Università degli Studi di Milano 20133 Milano Italy Samara Center for Theoretical Materials Science (SCTMS) Samara State Technical University Samara 443100 Russia

Metal-organic frameworks (MOFs) are known for their versatile combination of inorganic building units and organic linkers, which offers immense opportunities in a wide range of applications. However, many MOFs are typically synthesized as multiphasic polycrystalline powders, which are challenging for studies by X-ray diffraction. Therefore, developing new structural characterization techniques is highly desired in order to accelerate discoveries of new materials. Here, we report a high-throughput approach for structural analysis of MOF nano- and sub-microcrystals by three-dimensional electron diffraction (3DED). A new zeolitic-imidazolate framework (ZIF), denoted ZIF-EC1, was first discovered in a trace amount during the study of a known ZIF-CO 3 -1 material by 3DED. The structures of both ZIFs were solved and refined using 3DED data. ZIF-EC1 has a dense 3D framework structure, which is built by linking mono- and bi-nuclear Zn clusters and 2-methylimidazolates (mIm − ). With a composition of Zn 3 (mIm) 5 (OH), ZIF-EC1 exhibits high N and Zn densities. We show that the N-doped carbon material derived from ZIF-EC1 is a promising electrocatalyst for oxygen reduction reaction (ORR). The discovery of this new MOF and its conversion to an efficient electrocatalyst highlights the power of 3DED in developing new materials and their applications.

关键词： continuous rotation electron diffraction electrocatalysis high throughput structural analysis metal–organic frameworks three-dimensional electron diffraction

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Optimal verification and fidelity estimation of maximally entangled states

arXiv

引用

arXiv 2019年

作者： Zhu, Huangjun Hayashi, Masahito Department of Physics Center for Field Theory and Particle Physics Fudan University Shanghai200433 China State Key Laboratory of Surface Physics Fudan University Shanghai200433 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China Graduate School of Mathematics Nagoya University Nagoya464-8602 Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 Singapore117542 Singapore

We study the verification of maximally entangled states by virtue of the simplest measurement settings: local projective measurements without adaption. We show that optimal protocols are in one-to-one correspondence with complex projective 2-designs constructed from orthonormal bases. Optimal protocols with minimal measurement settings are in one-to-one correspondence with complete sets of mutually unbiased bases. Based on this observation, optimal protocols are constructed explicitly for any local dimension, which can also be applied to estimating the fidelity with the target state and to detecting entanglement. In addition, we show that incomplete sets of mutually unbiased bases are optimal for verifying maximally entangled states when the number of measurement settings is restricted. Moreover, we construct optimal protocols for the adversarial scenario in which state preparation is not trusted. The number of tests has the same scaling behavior as the counterpart for the nonadversarial scenario;the overhead is no more than three times. We also show that the entanglement of the maximally entangled state can be certified with any given significance level using only one test as long as the local dimension is large enough. Copyright © 2019, The Authors. All rights reserved.

关键词： Quantum entanglement

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Efficient Verification of Pure Quantum States in the Adversarial Scenario

arXiv

引用

arXiv 2019年

Efficient verification of pure quantum states in the adversarial scenario is crucial to many applications in quantum information processing, such as blind measurement-based quantum computation and quantum networks. However, little is known about this subject so far. Here we establish a general framework for verifying pure quantum states in the adversarial scenario and clarify the resource cost. Moreover, we propose a simple and general recipe to constructing efficient verification protocols for the adversarial scenario from protocols for the nonadversarial scenario. With this recipe, arbitrary pure states can be verified in the adversarial scenario with almost the same efficiency as in the nonadversarial scenario. Many important quantum states in quantum information processing can be verified in the adversarial scenario with unprecedented high efficiencies. Copyright © 2019, The Authors. All rights reserved.

关键词： Quantum optics

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General framework for verifying pure quantum states in the adversarial scenario

arXiv

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arXiv 2019年

Bipartite and multipartite entangled states are of central interest in quantum information processing and foundational studies. Efficient verification of these states, especially in the adversarial scenario, is a key to various applications, including quantum computation, quantum simulation, and quantum networks. However, little is know about this topic in the adversarial scenario. Here we initiate a systematic study of pure-state verification in the adversarial scenario. In particular, we introduce a general method for determining the minimal number of tests required by a given strategy to achieve a given precision. In the case of homogeneous strategies, we can even derive an analytical formula. Furthermore, we propose a general recipe to verifying pure quantum states in the adversarial scenario by virtue of protocols for the nonadversarial scenario. Thanks to this recipe, the resource cost for verifying an arbitrary pure state in the adversarial scenario is comparable to the counterpart for the nonadversarial scenario, and the overhead is at most three times for high-precision verification. Our recipe can readily be applied to efficiently verify bipartite pure states, stabilizer states, hypergraph states, weighted graph states, and Dicke states in the adversarial scenario. This paper is an extended version of the companion paper [1]. Copyright © 2019, The Authors. All rights reserved.

关键词： Quantum chemistry

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Plastic deformation analysis and forming quality prediction of tube N C bending

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Chinese Journal of Aeronautics 2016年第5期29卷 1436-1444页

作者： Lu Shiqiang Fang Jun Wang Kelu National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology School of Aeronautical Manufacturing Engineering Nanchang Hangkong University Nanchang 330063 China Jiangxi Key Laboratory of Surface Engineering Jiangxi Science and Technology Normal University Nanchang 330013 China

Plane strain assumption and exponent hardening law are used to investigate the plastic deformation in tube bending. Some theoretical formulae including stress, curvature radius of neutral layer, angle of neutral layer deviation, bending moment, wall thickness variation and crosssection distortion, are developed to explain the phenomena in tube bending and their magnitudes are also determined. During unloading process, the springback angle is deduced using the virtual work principle, and springback radius is also given according to the length of the neutral layer which remains unchanged before and after springback. The theoretical formulae are validated by the experimental results or the validated simulation results in literature, which can be used to auicklv predict the forming aualitv of tube numerical control （NC） bending.

关键词： Forming quality Plane strain Tube NC bending Theoretical analysis Virtual work principle

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Front Cover: Hollow Structure VS2@Reduced Graphene Oxide (RGO) Architecture for Enhanced Sodium-Ion Battery Performance (ChemElectroChem 1/2020)

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ChemElectroChem 2019年第1期7卷

作者： Haimei Qi Lina Wang Tiantian Zuo Shunlan Deng Prof. Qi Li Prof. Zong-Huai Liu Prof. Peng Hu Prof. Xuexia He Key Laboratory of Applied Surface and Colloid Chemistry Shaanxi Normal University) Ministry of Education Xi'an 710062 China Shaanxi Engineering Lab for Advanced Energy Technology School of Materials Science and Engineering Shaanxi Normal University Xi' an 710119 China School of Physics Northwest University Xi'an 710069 China

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Coexistence of Ferromagnetic and Stripe-Type Antiferromagnetic Spin Fluctuations in YFe2Ge2

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Physical Review Letters 2019年第21期122卷 217003-217003页

作者： Hongliang Wo Qisi Wang Yao Shen Xiaowen Zhang Yiqing Hao Yu Feng Shoudong Shen Zheng He Bingying Pan Wenbin Wang K. Nakajima S. Ohira-Kawamura P. Steffens M. Boehm K. Schmalzl T. R. Forrest M. Matsuda Yang Zhao J. W. Lynn Zhiping Yin Jun Zhao State Key Laboratory of Surface Physics and Department of Physics Fudan University Shanghai 200433 China Institute of Nanoelectronic Devices and Quantum Computing Fudan University Shanghai 200433 China Materials and Life Science Division J-PARC Center Tokai Ibaraki 319-1195 Japan Institut Laue-Langevin 71 Avenue des Martyrs 38042 Grenoble Cedex 9 France Forschungszentrum Jülich GmbH. Jülich Centre for Neutron Science at ILL 71 Avenue des Martyrs 38000 Grenoble France Diamond Light Source Harwell Campus Didcot OX11 0DE United Kingdom Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA NIST Center for Neutron Research National Institute of Standards and Technology Gaithersburg Maryland 20899 USA Department of Materials Science and Engineering University of Maryland College Park Maryland 20742 USA Department of Physics and Center for Advanced Quantum Studies Beijing Normal University Beijing 100875 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 China

We report neutron scattering measurements of single-crystalline YFe2Ge2 in the normal state, which has the same crystal structure as the 122 family of iron pnictide superconductors. YFe2Ge2 does not exhibit long-range magnetic order but exhibits strong spin fluctuations. Like the iron pnictides, YFe2Ge2 displays anisotropic stripe-type antiferromagnetic spin fluctuations at (π, 0, π). More interesting, however, is the observation of strong spin fluctuations at the in-plane ferromagnetic wave vector (0, 0, π). These ferromagnetic spin fluctuations are isotropic in the (H, K) plane, whose intensity exceeds that of stripe spin fluctuations. Both the ferromagnetic and stripe spin fluctuations remain gapless down to the lowest measured energies. Our results naturally explain the absence of magnetic order in YFe2Ge2 and also imply that the ferromagnetic correlations may be a key ingredient for iron-based materials.

关键词： Pairing mechanisms Spin dynamics Superconducting phase transition High-temperature superconductors Pnictides Neutron scattering

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Novel type of ferroelectricity in brownmillerite structures: A first-principles study

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Physical Review Materials 2018年第8期2卷 084402-084402页

作者： Hao Tian Xiao-Yu Kuang Ai-Jie Mao Yurong Yang Hongjun Xiang Changsong Xu S. Omid Sayedaghaee Jorge Íñiguez L. Bellaiche Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China Physics Department and Institute for Nanoscience and Engineering University of Arkansas Fayetteville Arkansas 72701 USA National Laboratory of Solid State Microstructures College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China Department of Physics Key Laboratory of Computational Physical Sciences (Ministry of Education) State Key Laboratory of Surface Physics Fudan University Shanghai 200433 China Microelectronics-Photonics Program and Physics Department University of Arkansas Fayetteville Arkansas 72701 USA Materials Research and Technology Department Luxembourg Institute of Science and Technology (LIST) 5 Avenue des Hauts-Fourneaux L-4362 Esch/Alzette Luxembourg

First-principles calculations are conducted on two magnetic brownmillerites, namely, Ca2Co2O5 and Sr2Co2O5. Both systems possess a previously overlooked polar Pmc21 phase that is low in energy. This ferroelectric state is even predicted to be the ground state of Sr2Co2O5, which therefore renders such material multiferroic. Strikingly, the ferroelectricity associated with this Pmc21 phase involves an original energetic coupling that is linear in the polar mode, quadratic in another distortion, and linear in a third mode. Such ferroelectricity is therefore of a novel type, since it differs from previously reported proper, improper, hybrid improper, and triggered kinds of ferroelectricity.

关键词： Defects Ferroelectricity First-principles calculations Crystal structures Multiferroics Oxides Density functional theory

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Revisiting spin cycloids in multiferroic BiFeO3

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Physical Review B 2018年第18期98卷 184420-184420页

作者： Bin Xu Bertrand Dupé Changsong Xu Hongjun Xiang L. Bellaiche School of Physical Science and Technology Soochow University Suzhou Jiangsu 215006 China Physics Department and Institute for Nanoscience and Engineering University of Arkansas Fayetteville Arkansas 72701 USA Institute of Physics INSPIRE Group Johannes Gutenberg-University Mainz 55128 Mainz Germany Key Laboratory of Computational Physical Sciences (Ministry of Education) State Key Laboratory of Surface Physics and Department of Physics Fudan University Shanghai 200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 People's Republic of China

We revisit the inverse spin current model that has been previously used to explain the existence of magnetic cycloids in bulk multiferroic BiFeO3. Using a first-principles-based effective Hamiltonian method, and in combination with Monte Carlo simulations, we predict a magnetic phase diagram as a function of first- and second-nearest-neighbor interaction strength in the spin current model and show that, in contrast with previous understanding, both first and second nearest neighbors have to be taken into account to be in accordance with experimental findings, including the existence of type-1 and type-2 cycloids with, respectively, [11¯0] and [112¯] propagation directions, and the cycloid-to-antiferromagnetic transition under magnetic field. Other previously unknown magnetic arrangements are found in this phase diagram. The microscopic origins of all its magnetic phases are further explained in terms of the coexistence of single solutions of the spin current model having different weights (in magnitude and even sign).

关键词： Electric polarization Ferroelectricity Magnetic interactions Magnetic order Magnetic texture Magnetoelectric effect Multiferroics Monte Carlo methods

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Phase equilibrium of Cd_(1-x)Zn_xS alloys studied by first-principles calculations and Monte Carlo simulations

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Chinese Physics B 2016年第1期25卷 549-555页

作者：张付珍薛红涛汤富领李小康路文江冯煜东 State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Department of Materials Science and EngineeringLanzhou University of TechnologyLanzhou 730050China Science and Technology on Surface Engineering Laboratory Lanzhou Institute of PhysicsLanzhou 730000China

The first-principles calculations based on density functional theory combined with cluster expansion techniques and Monte Carlo （MC） simulations were used to study the phase diagrams of both wurtzite （WZ） and zinc-blende （ZB） Cdl_xZnxS alloys. All formation energies are positive for WZ and ZB Cdl-xZnxS alloys, which means that the Cdl-xZnxS alloys are unstable and have a tendency to phase separation. For WZ and ZB Cdl_xZnxS alloys, the consolute temperatures are 655 K and 604 K, respectively, and they both have an asymmetric miscibility gap. We obtained the spatial distributions of Cd and Zn atoms in WZ and ZB *** alloys at different temperatures by MC simulations. We found that both WZ and ZB phases of *** alloy exhibit phase segregation of Cd and Zn atoms at low temperature, which is consistent with the phase diagrams.

关键词： first-principles calculation Monte Carlo simulations phase separation spatial distribution

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