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Highly Oxygen Non-Stoichiometric BaSc0.25Co0.75O3-δas a High-Performance Cathode for Intermediate-Temperature Solid Oxide Fuel Cells

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ChemElectroChem 2018年第5期5卷 785-792页

作者： Bo Liu Jaka Sunarso Yuan Zhang Guangming Yang Dr. Wei Zhou Zongping Shao Jiangsu National Synergetic Innovation Center for Advanced Materials State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing Tech University Nanjing 210009 China College of Chemical Engineering Nanjing Tech University Nanjing 210009 China Research Centre for Sustainable Technologies Faculty of Engineering Computing and Science Swinburne University of Technology Kuching 93350 Malaysia Department of Chemical Engineering Curtin University Western Australia 6845 Australia

Lowering the operating temperature of solid oxide fuel cells (SOFCs) is highly desirable to reduce the cost and increase the lifetime, which relies upon the development of a cathode component with high oxygen reduction reaction (ORR) activity at a lower temperature. Herein, we report the characterization of high-performance BaSc x Co 1- x O 3- δ ( x =0, 0.125, 0.25, and 0.375) perovskite SOFC cathodes. Unlike BaCoO 3- δ , which adopts 2H-hexagonal perovskite structure, the replacement of 25 mol % of Co with Sc stabilizes the cubic structure, which also leads to the significant reduction in area specific resistances and their activation energies between 650 and 500 °C (for BaSc 0.25 Co 0.75 O 3- δ ) relative to the non-doped BaCoO 3- δ . In this temperature range, BaSc 0.25 Co 0.75 O 3- δ displayed a remarkably high ORR activity compared to Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF), the current cathode benchmark. We attribute such superior ORR performance to the higher oxygen non-stoichiometries of BaSc 0.25 Co 0.75 O 3 -δ relative to BSCF, which also translates to the higher oxygen bulk diffusion and surface exchange coefficients for the former compared to the latter. As a result, a single fuel cell based on an anode-supported 20 μm thick samarium-doped ceria electrolyte and BaSc 0.25 Co 0.75 O 3- δ cathode achieved a very high peak power density of 1723 mW cm −2 at 650 °C. We also demonstrated the possibility to increase the ORR activity of the BaSc 0.25 Co 0.75 O 3-δ cathode by impregnation of a low amount of silver.

关键词： solid oxide fuel cells perovskites cathode high oxygen non-stoichiometry

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MCSMGS:Malware Classification Model Based on Deep Learning

MCSMGS:Malware Classification Model Based on Deep Learning

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第九届网络分布式计算与知识发现国际会议( 2017 International Conference on Cyber-enabled distributed computing and knowledge discovery)

作者： Zhen Shan Jing Wang Fudong Liu Bingling Zhao Xi Meng Jin Han Hongyan Wang State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou China Division of Information Theory Aviation University of Air Force Changchun China

As a major threat to cyber security,malware has been increasingly damaging national *** paper proposes a malware classification model,*** model(Malware Classification Based on Static Malware Gene Sequences),that combines the static malware genes with deep learning *** model extracts the malware gene sequences that have both material attribute and informational *** it makes distributed representation for each malware gene to represent the intrinsic correlation and ***,the SMGS_CNN(Static Malware Gene Sequences--Convolution Neural Network)module is used to construct the neural network to analyze the malware gene sequences and realize malware *** experimental results show that the classification accuracy is greatly improved and up to 98%with the MCSMGS *** model is more effective than the traditional SVM model.

关键词： malware gene sequence intrinsic correlation similarity neural network classification

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Observation of a Dynamical Sliding Phase Superfluid with P-Band Bosons

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Physical Review Letters 2018年第26期121卷 265301-265301页

作者： Linxiao Niu Shengjie Jin Xuzong Chen Xiaopeng Li Xiaoji Zhou School of Electronics Engineering and Computer Science Peking University Beijing 100871 China State Key Laboratory of Surface Physics Institute of Nanoelectronics and Quantum Computing and Department of Physics Fudan University Shanghai 200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 China

Sliding phases have been long sought after in the context of coupled XY models, as they are of relevance to various many-body systems such as layered superconductors, freestanding liquid-crystal films, and cationic lipid-DNA complexes. Here we report an observation of a dynamical sliding phase superfluid that emerges in a nonequilibrium setting from the quantum dynamics of a three-dimensional ultracold atomic gas loaded into the P band of a one-dimensional optical lattice. A shortcut loading method is used to transfer atoms into the P band at zero quasimomentum within a very short time duration. The system can be viewed as a series of “pancake”-shaped atomic samples. For this far-out-of-equilibrium system, we find an intermediate time window with a lifetime around tens of milliseconds, where the atomic ensemble exhibits robust superfluid phase coherence in the pancake directions, but no coherence in the lattice direction, which implies a dynamical sliding phase superfluid. The emergence of the sliding phase is attributed to a mechanism of cross-dimensional energy transfer in our proposed phenomenological theory, which is consistent with experimental measurements. This experiment potentially opens up a novel venue to search for exotic dynamical phases by creating high-band excitations in optical lattices.

关键词： Bose-Einstein condensates Cold gases in optical lattices Decoherence in quantum gases Superfluidity

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Amplitude death in globally coupled oscillators with time-scale diversity

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Physical Review E 2018年第6期98卷 062209-062209页

作者： Wei Zou Meng Zhan Jürgen Kurths School of Mathematical Sciences South China Normal University Guangzhou 510631 People's Republic of China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China Potsdam Institute for Climate Impact Research Telegraphenberg Potsdam D-14415 Germany Institute of Physics Humboldt University Berlin Berlin D-12489 Germany Saratov State University 4410012 Saratov Russia

We analyze amplitude death (AD) in large systems of globally coupled oscillators with randomly distributed time scales. We show that the distribution of characteristic eigenvalues of a large but finite system is well approximated by the continuous and discrete spectra of the system in the thermodynamic limit. The stability analysis from the continuous and discrete spectra of the infinite system provides a fairly accurate prediction for the onset of AD in the large finite system. We prove the argument by examining the stability of AD in a paradigmatic system of coupled Stuart-Landau limit cycles with mismatched time scales. The proposed technique is extended to systems of globally coupled nonlinear oscillators of a general form with time-scale diversity, which is verified in coupled chaotic Rössler oscillators. Our study provides analytical insight into the understanding of the emergence of AD in populations of globally coupled dynamical systems.

关键词： Coupled oscillators

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Joint adaptive neighbours and metric learning for multi-view subspace clustering

arXiv

引用

arXiv 2017年

作者： Xu, Nan Guo, Yanqing Wang, Jiujun Luo, Xiangyang He, Ran School of Information and Communication Engineering Dalian University of Technology State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou Science and Technology Institute National Laboratory of Pattern Recognition CASIA

Due to the existence of various views or representations in many real-world data, multi-view learning has drawn much attention recently. Multi-view spectral clustering methods based on similarity matrixes or graphs are pretty popular. Generally, these algorithms learn informative graphs by directly utilizing original data. However, in the real-world applications, original data often contain noises and outliers that lead to unreliable graphs. In addition, different views may have different contributions to data clustering. In this paper, a novel Multi-view Subspace Clustering method unifying Adaptive neighbours and Metric learning (MSCAM), is proposed to address the above problems. In this method, we use the subspace representations of different views to adaptively learn a consensus similarity matrix, uncovering the subspace structure and avoiding noisy nature of original data. For all views, we also learn different Mahalanobis matrixes that parameterize the squared distances and consider the contributions of different views. Further, we constrain the graph constructed by the similarity matrix to have exact c (c is the number of clusters) connected components. An iterative algorithm is developed to solve this optimization problem. Moreover, experiments on a synthetic dataset and different real-world datasets demonstrate the effectiveness of MSCAM. Copyright © 2017, The Authors. All rights reserved.

关键词： Cluster analysis

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Dynamic formation of quasicondensate and spontaneous vortices in a strongly interacting Fermi gas

arXiv

引用

arXiv 2019年

作者： Liu, Xiang-Pei Yao, Xing-Can Deng, Youjin Wang, Yu-Xuan Wang, Xiao-Qiong Li, Xiaopeng Chen, Qijin Chen, Yu-Ao Pan, Jian-Wei Hefei National Laboratory for Physical Sciences at the Microscale Department of Modern Physics University of Science and Technology of China Hefei230026 China Shanghai Branch CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Shanghai201315 China Shanghai Research Center for Quantum Sciences Shanghai201315 China State Key Laboratory of Surface Physics Institute of Nanoelectronics and Quantum Computing Department of Physics Fudan University Shanghai200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China MinJiang Collaborative Center for Theoretical Physics College of Physics and Electronic Information Engineering Minjiang University Fuzhou350108 China

We report an experimental study of quench dynamics across the superfluid transition temperature Tc in a strongly interacting Fermi gas by ramping down the trapping potential. The nonzero quasi-condensate number N0 at temperature significantly above Tc in the unitary and the BEC regimes reveals the pseudogap physics. Below Tc, a rapid growth of N0 is accompanied by spontaneous generation of tens of vortices. We observe a power law scaling of the vortex density versus the quasi-condensate formation time, consistent with the Kibble-Zurek theory. Our work provides an example of studying emerged many-body physics by quench dynamics and paves the way for studying the quantum turbulence in a strongly interacting Fermi gas. Copyright © 2019, The Authors. All rights reserved.

关键词： Electron gas

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Observation of a dynamical sliding phase superfluid with P-band bosons

arXiv

引用

arXiv 2018年

作者： Niu, Linxiao Jin, Shengjie Chen, Xuzong Li, Xiaopeng Zhou, Xiaoji School of Electronics Engineering and Computer Science Peking University Beijing100871 China State Key Laboratory of Surface Physics Institute of Nanoelectronics and Quantum Computing Department of Physics Fudan University Shanghai200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China

Sliding phases have been long sought-after in the context of coupled XY-models, of relevance to various many-body systems such as layered superconductors, free-standing liquid-crystal films, and cationic lipid-DNA complexes. Here we report an observation of a dynamical sliding-phase superfluid that emerges in a nonequilibrium setting from the quantum dynamics of a three-dimensional ultracold atomic gas loaded into the P-band of a one-dimensional optical lattice. A shortcut loading method is used to transfer atoms into the P-band at zero quasi-momentum within a very short time duration. The system can be viewed as a series of "pancake"-shaped atomic samples. For this far-out-of-equilibrium system, we find an intermediate time window with lifetime around tens of milliseconds, where the atomic ensemble exhibits robust superfluid phase coherence in the pancake directions, but no coherence in the lattice direction, which implies a dynamical sliding-phase superfluid. The emergence of the sliding phase is attributed to a mechanism of cross-dimensional energy transfer in our proposed phenomenological theory, which is consistent with experimental measurements. This experiment potentially opens up a novel venue to search for exotic dynamical phases by creating high-band excitations in optical lattices. Copyright © 2018, The Authors. All rights reserved.

关键词： Liquid films

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Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

arXiv

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arXiv 2022年

作者： Cao, Zhen Aharonian, F. An, Q. Axikegu Bai, L.X. Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, J.T. Cao, Zhe Chang, J. Chang, J.F. Chen, E.S. Chen, Liang Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, Y. Cheng, H.L. Cheng, N. Cheng, Y.D. Cui, S.W. Cui, X.H. Cui, Y.D. D'Ettorre Piazzoli, B. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu Della Volpe, D. Duan, K.K. Fan, J.H. Fan, Y.Z. Fan, Z.X. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, X.T. Feng, Y.L. Gao, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, S.L. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S. Hu, S.C. Hu, X.J. Huang, D.H. Huang, W.H. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.C. Ji, X.L. Jia, H.Y. Jia, K. Jiang, K. Jiang, Z.J. Jin, M. Kang, M.M. Ke, T. Kuleshov, D. Levochkin, K. Li, B.B. Li, Cheng Li, Cong Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, Jian Li, Jie Li, K. Li, W.L. Li, X.R. Li, Xin Li, Y.Z. Li, Zhe Li, Zhuo Liang, E.W. Liang, Y.F. Lin, S.J. Liu, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.S. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y.N. Long, W.J. Lu, R. Luo, Q. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Masood, A. Min, Z. Mitthumsiri, W. Nan, Y.C. Ou, Z.W. Pang, B.Y. Pattarakijwanich, P. Pei, Z.Y. Qi, M.Y. Qi, Y.Q. Qiao, B.Q. Qin, J.J. Ruffolo, D. Sáiz, A. Shao, C.Y. Shao, L. Shchegolev, O. Sheng, X.D. Shi, J.Y. Song, H.C. Stenkin, Yu.V. Stepanov, V. Su, Y. Sun, Q.N. Sun, X.N. Sun, Z.B. Tam, P.H.T. Tang, Z.B. Tian, W.W. Wang, B.D. Wang, C. Wang, H. Wang, H.G. Wang, J.C. Wang, J.S. Key Laboratory of Particle Astrophyics Experimental Physics Division Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China Tianfu Cosmic Ray Research Center Sichuan Chengdu China Dublin Institute for Advanced Studies 31 Fitzwilliam Place 2 Dublin Ireland Max-Planck-Institut for Nuclear Physics P.O. Box 103980 Heidelberg69029 Germany State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of China Anhui Hefei230026 China School of Physical Science and Technology School of Information Science and Technology Southwest Jiaotong University Sichuan Chengdu610031 China College of Physics Sichuan University Sichuan Chengdu610065 China School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210023 China Center for Astrophysics Guangzhou University Guangdong Guangzhou510006 China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Ministry of Education Tibet Lhasa850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Hebei Normal University Hebei Shijiazhuang050024 China Zhuhai519000 China Dipartimento di Fisica Dell'Università di Napoli 'Federico II' Complesso Universitario di Monte Sant'Angelo via Cinthia Napoli80126 Italy School of Physics and Astronomy Yunnan University Yunnan Kunming650091 China Département de Physique Nucléaire et Corpusculaire Faculté de Sciences Université de Genève 24 Quai Ernest Ansermet Geneva1211 Switzerland Institute of Frontier and Interdisciplinary Science Shandong University Shandong Qingdao266237 China Department of Engineering Physics Tsinghua University Beijing100084

The kilometer squarearray (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γrays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 105and 109GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission. © 2022, CC BY.

关键词： Gamma rays

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Cu/ZnO Catalysts: Cu/ZnO Catalysts Derived from Bimetallic Metal–Organic Framework for Dimethyl Ether Synthesis from Syngas with Enhanced Selectivity and Stability (Small 14/2020)

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Small 2020年第14期16卷

作者： Fuping Li Min Ao Gia Hung Pham Jaka Sunarso Yanping Chen Jian Liu Kai Wang Shaomin Liu Discipline of Chemical Engineering WA School of Mines: Minerals Energy and Chemical Engineering Curtin University GPO Box U1987 Perth Western Australia 6845 Australia Research Centre for Sustainable Technologies Faculty of Engineering Computing and Science Swinburne University of Technology Jalan Simpang Tiga Kuching 93350 Sarawak Malaysia State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian National Laboratory for Clean Energy 457 Zhongshan Road Dalian 116023 China DICP-Surrey Joint Centre for Future Materials Department of Chemical and Process Engineering University of Surrey Guildford Surrey UK Beijing Advanced Innovation Centre for Soft Matter Science and Engineering College of Chemical Engineering Beijing University of Chemical Technology Beijing 100029 China

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On-line memorry defragmentation for NVM-based persistent heaps 6

On-line memorry defragmentation for NVM-based persistent hea...

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6th IEEE Non-Volatile Memory Systems and Applications Symposium, NVMSA 2017

作者： Li, Lin Jiang, Wei Pan, Rui Zhan, Jinyu Shao, Zili Xiong, Xiankui School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu China School of Information and Software Engineering University of Electronic Science and Technology of China Chengdu China Department of Computing Hong Kong Polytechnic University Hong Kong Hong Kong Zhongxing Telecommunication Equipment Corporation Nanjing China State Key Lab of Mathematical Engineering and Advanced Computing Wuxi China

ISBN: (纸本)9781538617687

Due to the durability of NVM, we are facing the great challenge of performing efficient memory defragmentation on persistent heaps. To address the problem, we propose an Online Persistent Memory Defragmentation (OPMD) method to manage persistent heaps. Employing two segment trees to track memory allocation and deallocation operations, our method can amortize the cost of global scan, and determine the most valuable objects needed to be moved in logarithmic time. OPMD adopts software transactional memory to move objects and updates object references in constant time using object metadata. We conduct extensive experiments to test the impact of OPMD on the throughput of the operations of linked list and hash table. © 2017 IEEE.

关键词： Resource management Metadata Nonvolatile memory Memory management Tracking Throughput Random access memory

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