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arXiv 2020年

作者： Lu, Zhen-Yan Du, Meng-Lin Guo, Feng-Kun Meißner, Ulf-G Vonk, Thomas School of Physics and Electronic Science Hunan University of Science and Technology Xiangtan411201 China CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China Helmholtz-Institut für Strahlen- und Kernphysik Bethe Center for Theoretical Physics Universität Bonn BonnD-53115 Germany School of Physical Sciences University of Chinese Academy of Sciences Beijing100049 China Institute for Advanced Simulation Institut für Kernphysik Jülich Center for Hadron Physics Forschungszentrum Jülich JülichD-52425 Germany Tbilisi State University Tbilisi0186 Georgia

At low energies, the strong interaction is governed by the Goldstone bosons associated with the spontaneous chiral symmetry breaking, which can be systematically described by chiral perturbation theory. In this paper, we apply this theory to study the θvacuum energy density and hence the QCD axion potential up to next-to-leading order with N non-degenerate quark masses. By setting N = 3, we then derive the axion mass, self-coupling, topological susceptibility and the normalized fourth cumulant both analytically and numerically, taking the strong isospin breaking effects into account. In addition, the model-independent part of the axion-photon coupling, which is important for axion search experiments, is also extracted from the chiral Lagrangian supplemented with the anomalous terms up to O(p6). Copyright © 2020, The Authors. All rights reserved.

关键词： Perturbation techniques

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SVM-based deep stacking networks

arXiv

引用

arXiv 2019年

作者： Wang, Jingyuan Feng, Kai Wu, Junjie MOE Engineering Research Center of Advanced Computer Application Technology School of Computer Science Engineering Beihang University Beijing100191 China Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operations School of Economics and Management Beihang University Beijing100191 China Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing100191 China

The deep network model, with the majority built on neural networks, has been proved to be a powerful framework to represent complex data for high performance machine learning. In recent years, more and more studies turn to nonneural network approaches to build diverse deep structures, and the Deep Stacking Network (DSN) model is one of such approaches that uses stacked easy-to-learn blocks to build a parameter-training-parallelizable deep network. In this paper, we propose a novel SVM-based Deep Stacking Network (SVM-DSN), which uses the DSN architecture to organize linear SVM classifiers for deep learning. A BP-like layer tuning scheme is also proposed to ensure holistic and local optimizations of stacked SVMs simultaneously. Some good math properties of SVM, such as the convex optimization, is introduced into the DSN framework by our model. From a global view, SVM-DSN can iteratively extract data representations layer by layer as a deep neural network but with parallelizability, and from a local view, each stacked SVM can converge to its optimal solution and obtain the support vectors, which compared with neural networks could lead to interesting improvements in anti-saturation and interpretability. Experimental results on both image and text data sets demonstrate the excellent performances of SVM-DSN compared with some competitive benchmark models. Copyright © 2019, The Authors. All rights reserved.

关键词： Convex optimization

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Improving hazard analysis of integrated modular avionics system based on system-theoretic process analysis 18th

Improving hazard analysis of integrated modular avionics sys...

引用

18th AIAA aviation technology, Integration, and Operations Conference, 2018

作者： Rong, Hao Gu, Qingfan Chen, Zhixiong Xu, Desheng China National Aeronautical Radio Electronics Research Institute Civil Aviation Department No.432 Zi Yue Road Shanghai China Science and Technology on Avionics Integration Laboratory Civil Aviation Department No.432 Zi Yue Road Shanghai China State Key Laboratory for Civil Aircraft Flight Simulation Commercial Aircraft Corporation of China Ltd. No.5188 Jin Ke Road Shanghai China

ISBN: (纸本)9781624105562

Integrated modular avionics systems bring new concepts and benefits for function integration and resource utilization in developing advanced aircraft avionics, as well as a series of challenges related to hazard analysis in components interaction and functions operation. When software applications provided independently by the subsystem developers are integrated onto the IMA hardware platform, it is very difficult for designers to understand and predict how the system will behave and what interaction hazards could occur. Although the ARP 4761-based safety analysis methods have solved a large number of safety problems on the development of civil aircraft and system designs in early times, there are some limitations when analyzing more and more complex integrated modular avionics systems in modern times. To gain a good or better understanding and a comprehensive awareness of applications interaction hazards in today’s more complex, software-intensive IMA systems, it is significant to use a method to consider these new causal factors that are not handled by the older techniques and to provide more guidance to the analyst in performing hazard analysis. System-Theoretic Process Analysis (STPA) is one of typical systemic hazard analysis methods. STPA has its foundation in a new accident causality model called STAMP (System-Theoretic Accident Model and Process). STAMP was proposed based on the cybernetics of systems theory. In STAMP, the dysfunctional interactions and requirements flaws during operation are primary types of inadequate control. The STPA-based hazard analysis method is extended in this paper to account for behavior that emerges when software applications are integrated and make functional interaction. This method will be capable of modeling the new causal factors that contribute to component interaction hazards. The paper illustrates the new method with a case that includes real-world avionics display functions, this application of the proposed method will b

关键词： Hazards

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Influence mechanism of Cu on high temperature oxidation behavior of titanium alloys

Influence mechanism of Cu on high temperature oxidation beha...

引用

Chinese Materials Conference, 2018

作者： Chen, Hang Mi, Guang-Bao Li, Pei-Jie Cao, Chun-Xiao National Center of Novel Materials for International Research Tsinghua University Beijing100084 China Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys Beijing Institute of Aeronautical Materials Beijing100095 China Beijing Engineering Research Center of Graphene and Application Beijing100095 China

ISBN: (纸本)9783035713848

The oxidation behavior and mechanism of Ti-Cu alloys (0≤w(Cu)≤20%) in the temperature range of 1000°C~1300°C were studied by thermogravimetric analysis(TGA) combined with SEM, EDS and XRD analysis methods. The results showed that the oxidation rates of Ti-Cu alloys increased sharply when the temperature rised above 1000 °C. The oxidation products had a three-layer structure, from the outside to the inside, which were dense outer oxide layer of TiO2, porous inner oxide layer of low valence oxide of Ti and Cu-enriched layer. With the increase of the temperature, the thicknesses of oxide layers of Ti-Cu alloy increased and the Cu-enriched phase increased gradually and melts. The melting Cu-enriched phase flowed to the oxidation surface along the grain boundaries of the oxide layer. The high temperature oxidation resistance of Ti-Cu alloys declined with the increase of Cu content. The main reason is that more liquid Cu-enriched phase is formed and flows to the oxidation surface along the oxide grain boundaries in the Ti-Cu alloy, and Ti and O ions can diffuse more easily along the liquid Cu-enriched phase, which increases the oxidation rates. © 2019 Trans Tech Publications, Switzerland.

关键词： Binary alloys

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Bionic Optimization Design of Electronic Nose Chamber for Oil and Gas Detection

引用

Journal of Bionic Engineering 2018年第3期15卷 533-544页

作者： Zhiyong Chang Youhong Sun Yuchen Zhang Yanli Gao Xiaohui Weng Donghui Chen Liewe David Jun Xie Key Lab of Advanced Technologies of Materials Ministry of Education School of Materials Science and Engineering Southwest Jiaotong University Chengdu 610031 China Key Laboratory of Bionic Engineering Ministry of Education Jilin University Changchun 130022 China National-Local Joint Engineering Laboratory of In-situ Conversion Drilling and Exploitation Technology for Oil Shale Jilin University Changchun 130021 China College of Construction Engineering Jilin University Changchun 130022 China Clinical Medicine Bethune First Hospital of Jilin University Changchun 130021China College of Mechanical Science and Engineering Jilin University Changchun 130022 China School of Computing and Technology the University of Gloucestershire The Park Cheltenham GL50 2RH UK Air Combat Service Academy Air Force Aviation University Changchun 130021 China

In this paper, a miniaturized bionic electronic nose system is developed in order to solve the problems arising in oil and gas detection for large size and inflexible operation in downhole. The bionic electronic nose chamber is designed by mimicking human nasal turbinate structure, V-groove structure on shark skin surface and flow field distribution around skin surface. The sensitivity of the bionic electronic nose system is investigated through experimentation. Radial Basis Function （RBF） and Support Vector Machines （SVM） of 10-fold cross validation are used to compare the recognition performance of the bionic electronic nose system and common one. The results show that the sensitivity of the bionic electronic nose system with bionic composite chamber （chamber B） is significantly improved compared with that with common chamber （chamber A）. The recognition rate of chamber B is 4.27% higher than that of chamber A for the RBF algorithm, while for the SVM algorithm, the recognition rate of chamber B is 5.69% higher than that of chamber A. The three-dimensional simulation model of the chamber is built and verified by Computational Fluid Dynamics （CFD） simulation analysis. The number of vortices in chamber B is fewer than that in chamber A. The airflow velocity near the sensors inside chamber B is slower than that inside chamber A. The vortex intensity near the sensors in chamber B is 2.27 times as much as that in chamber A, which facilitates gas molecules to fully contact with the sensor surface and increases the intensity of sensor signal, and the contact strength and time between odorant molecules and sensor surface. Based on the theoretical investigation and test validation, it is believed that the proposed bionic electronic nose system with bionic composite chamber has potential for oil and gas detection in downhole.

关键词： electronic nose bionic chamber sensors oil gas detection

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Design and simulation of a Micromechanical Silicon Resonant Accelerometer with Low Temperature Sensitivity

Design and Simulation of a Micromechanical Silicon Resonant ...

引用

International Conference on Instrumentation, Measurement, Computer, Communication and Control (IMCCC)

作者： Yang Gao Hongsheng Li Libin Huang Songli Wang School of Instrument Science and Engineering Southeast University Nanjing China Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology Southeast University Ministry of Education Nanjing China Aviation Key Laboratory of Science and Technology on Inertia FACRI Xi'an China

ISBN: (数字)9781538682463

ISBN: (纸本)9781538682470

Because of the mismatch of material properties between silicon and glass, especially the mismatching thermal expansion coefficients, the Micromechanical Silicon Resonant Accelerometer based on the Deep Dry Silicon On Glass (DDSOG) technique is seriously affected by the temperature during the fabrication, packaging and use processes. Based on the working principle and temperature characteristics of Micromechanical Silicon Resonant Accelerometer, the effect of the mismatching thermal expansion coefficients of silicon and glass is analyzed, and a Single-Anchor-Supported accelerometer structure with low temperature sensitivity is designed. simulation results show that the structure can effectively reduce the effect of mismatching thermal expansion coefficients of silicon and glass.

关键词：

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AlphaStock: A buying-winners-and-selling-losers investment strategy using interpretable deep reinforcement attention networks

arXiv

引用

arXiv 2019年

作者： Wang, Jingyuan Zhang, Yang Tang, Ke Wu, Junjie Xiong, Zhang MOE Engineering Research Center of Advanced Computer Application Technology School of Computer Science Engineering Beihang University Beijing China Institute of Economics School of Social Sciences Tsinghua University Beijing China Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operations School of Economics and Management Beihang University Beijing China Beijing Advanced Innovation Center for BDBC Beihang University Beijing China

Recent years have witnessed the successful marriage of finance innovations and AI techniques in various finance applications including quantitative trading (QT). Despite great research efforts devoted to leveraging deep learning (DL) methods for building better QT strategies, existing studies still face serious challenges especially from the side of finance, such as the balance of risk and return, the resistance to extreme loss, and the interpretability of strategies, which limit the application of DL-based strategies in real-life financial markets. In this work, we propose AlphaStock, a novel reinforcement learning (RL) based investment strategy enhanced by interpretable deep attention networks, to address the above challenges. Our main contributions are summarized as follows: i) We integrate deep attention networks with a Sharpe ratio-oriented reinforcement learning framework to achieve a risk-return balanced investment strategy;ii) We suggest modeling interrelationships among assets to avoid selection bias and develop a cross-asset attention mechanism;iii) To our best knowledge, this work is among the first to offer an interpretable investment strategy using deep reinforcement learning models. The experiments on long-periodic U.S. and Chinese markets demonstrate the effectiveness and robustness of AlphaStock over diverse market states. It turns out that AlphaStock tends to select the stocks as winners with high long-term growth, low volatility, high intrinsic value, and being undervalued recently. Copyright © 2019, The Authors. All rights reserved.

关键词： Strategic planning

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Detection of Picric Acid by Terpy-Based Metallo- Supramolecular Fluorescent Coordination Polymers in Aqueous Media

引用

Chinese Journal of Chemistry 2017年第4期35卷 447-456页

作者： Zhongyu Ding Hongqing Li Wanqing Gao Yiquan Zhang Chunhua Liu Yuanyuan Zhu School of Chemistry and Chemical Engineering Hefei University of Technology and Anhui Key Laboratory of Advanced Functional Materials and Devices Hefei Anhui 230009 China Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems (NSLSCS) School of Physical Science and Technology Nanjing Normal University Nanjing Jiangsu 210023 China

The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1 ： 1 complexation of Zn^2＋ and Cd^2＋ ions with ditopic terpyridine ligand was reported. The dispersibility of P1 and P2 was significantly improved in organic solvent and water through the introduction of hydrophilic oligo-ethyoxy side chain. Two polymers displayed yellow light emission both in solution and the solid state due to the intra-ligand charge transfer （ILCT） between the d^10 metal ions and the conjugated spacer unit. These coordination polymers were explored as fluorescent chemosensors for detecting picric acid in aqueous media, displaying high sensitivity and good selectivity. In addition, test strips were prepared from these polymers and exhibited the practical potential of detecting the NACs pollutants in the outdoor water for public safety and security.

关键词： coordination polymer fluorescent chemosensors nitroaromatic explosives picric acid aqueous media

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Rotation sensing in two coupled whispering-gallery-mode resonators with loss and gain

arXiv

引用

arXiv 2019年

作者： Tian, T. Wang, Zhihai Song, L.J. School of Science Changchun University Changchun130022 China Key Laboratory of Materials Design and Quantum Simulation Changchun University Changchun130022 China Center for Quantum Sciences School of Physics Northeast Normal University Changchun130024 China Center for Advanced Optoelectronic Functional Materials Research Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education Northeast Normal University Changchun130024 China Jilin Engineering Normal University Changchun130052 China

We theoretically propose a scheme to realize the rotation sensing based on two coupled whispering-gallery-mode resonators system with the active resonantor being rotated while the passive one being stationary. We show that the rotation induced Sagnac effect will shift the eigen-frequency of the supermodes. We can measure the average photon number in the steady state or the fluctuation spectrum of the output field to detect the angular velocity of the rotation. We hope that our investigation will be useful in the designing of quantum gyroscope based on spinning resonators. Copyright © 2019, The Authors. All rights reserved.

关键词： Rotation

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Control of Stray Currents in Pipeline System based on Melnikov Theory 36

Control of Stray Currents in Pipeline System based on Melnik...

引用

第36届中国控制会议

作者： Peng Wang Bohu Li Guoqiang Shi Junhua Zhou School of Automation Science and Electrical Engineering BeiHang University Beijing Complex Product Advanced Manufacturing Engineering Research Center Beijing Simulation Center State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System Science and Technology on Space System Simulation Laboratory Beijing Simulation Center

ISBN: (纸本)9781538629185

The pipeline network interfered by the stray currents has been verified to be a complex nonlinear dynamical *** paper shows that the chaotic characteristic could be utilized in the stray currents *** prove this,this paper establishes an equivalent chaotic control *** we analyze this model by using Melnikov method and find out the condition under which the chaotic phenomenon will be *** order to get a sufficient proof for identifying the conclusion,simulation experiments are used to verify the validity of the control method.

关键词： stray currents chaos control Melnikov

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