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arXiv 2019年

作者： Yan, Da-Cheng Liu, Xin Xiao, Zhen-Jun Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China School of Physics and Electronic Engineering Jiangsu Normal University Xuzhou221116 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

By employing the perturbative QCD (PQCD) factorization approach, we made a systematic investigation for the CP-averaged branching ratios and the CP-violating asymmetries of the thirteen B¯s0 → P P decays (here P = (π, K, η, η′)) with the inclusion of all currently known next-to-leading order (NLO) contributions, and compared our results with the measured values or the theoretical predictions from other different approaches. We focused on the examination of the effects of the NLO contributions and found the following points: (a) for B¯s0 → (K0K¯ 0, K+K−, η′η′, π−K+) decays, the NLO contributions can provide a (40 − 150)% enhancement or a 20% reduction to the corresponding leading order (LO) PQCD predictions for their decay rates and result in a much better agreement between the PQCD predictions and the experimental measurements;(b) for the pure annihilation decay B¯s0 → π+π−, the PQCD prediction still remain consistent with the data after the inclusion of the small NLO reduction;(c) the PQCD predictions for the ratio (fs/fd) · B(Bs0 → π+π−)/B(B0 → K+π−) and (fs/fd) · B(Bs0 → π+K−)/B(B0 → K+π−) become agree very well with the measured ones after the inclusion of a 40% NLO reduction;(d) for B¯s0 → K+K− and B¯s0 → π−K+ decays, the NLO PQCD predictions for their CP-violating asymmetries do agree very well with the measured values in both the sign and the magnitude;and (e) for all B¯s0 → P P decays, we also compared our results with those obtained in the QCD factorization approach and soft-collinear effective theory and discussed their similarities and differences. Copyright © 2019, The Authors. All rights reserved.

关键词： Forecasting

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Anatomy of Bs → P V decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

arXiv

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arXiv 2017年

作者： Yan, Da-Cheng Yang, Ping Liu, Xin Xiao, Zhen-Jun Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China School of Physics and Electronic Engineering Jiangsu Normal University Xuzhou221116 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one B¯s0 → P V decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide ∼ 40% enhancement to the LO PQCD predictions for B(B¯s0 → K0K¯ ∗0) and B(B¯s0 → K±K∗), or a ∼ 37% reduction to B(B¯s0 → π−K∗+);and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements;(b) the total effects on the PQCD predictions for the relevant B → P transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than 10% enhancement respect to the leading order result;(c) for the "tree" dominated decay B¯s0 → K+ρ− and the "color-suppressed-tree" decay B¯s0 → π0K∗0, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude AT,C and AP: constructive for the first decay but destructive for the second one;and (d) for B¯s0 → V (η, η′) decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude A(V ηq) and A(V ηs) due to the η − η′ mixing. Copyright © 2017, The Authors. All rights reserved.

关键词： Forecasting

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Fragmentation of faceted crystalline wires

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Physical Review Materials 2022年第10期6卷 106002-106002页

作者： Nan Wang Alain Karma Department of Materials Science and Engineering Guangdong Technion - Israel Institute of Technology Shantou Guangdong 515063 China Physics Department and Center for Interdisciplinary Research on Complex Systems Northeastern University Boston Massachusetts 02115 USA Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion Guangdong Technion - Israel Institute of Technology Shantou Guangdong 515063 China Technion - Israel Institute of Technology Haifa 32000 Israel

The reduction of surface energy is a well-known driving force for the fragmentation of nanowires. Fragmentation can limit the service life of those small low-dimensional building blocks or can be controlled to induce beneficial shape changes. For isotropic surface energy, fragmentation is analogous to the classic Rayleigh-Plateau instability of liquid jets. However, commonly synthesized crystalline nanowires have strongly anisotropic surface energies and exhibit facets coinciding with cusps in the Wulff plot. Depending on growth orientation, different fragmentation behaviors have been seen in nanowires. Using phase-field simulations, we show that fragmentation of faceted nanowires with cubic crystal symmetry may occur by a finite-amplitude nonlinear instability, as opposed to a Rayleigh-Plateau-like linear instability, depending on nanowire growth orientation. We carry out a weakly nonlinear analysis based on sharp interface theory to characterize the faceted nanowire shape corresponding to a surface-energy saddle point. The analysis predicts that the minimum amplitude of a periodic shape perturbation to trigger fragmentation increases with cusp strength but decreases inversely proportionally to the perturbation wavelength for long wavelengths, in good quantitative agreement with phase-field predictions. The results provide the theoretical foundation to predict nanowire stability as a function of length and surface energy in diverse applications.

关键词： Nanowires Phase-field modeling

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Convective heat transfer of air flow in cold cabinet with two-fluid model

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Huagong Xuebao/CIESC Journal 2012年第SUPPL.1期63卷 138-144页

作者： Wei, Min Wang, Limin State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The convective heat transfer of the cold cabinet was investigated by using two-fluid model after the effectiveness of new model was confirmed. This study includes the influence of wind speeds, wind directions and speeds of air curtain. The results show that the convective heat transfer is improved along with increasing of the wind speed. In a relatively short time, there is a linear relationship between convective heat transfer and time. The wind direction has small effect on heat transfer when it is less than about 15° while has appreciable impact and made an increase of energy consumption by approximately 30% when it reaches 30°. The air curtain, a major constituent of the refrigeration system of cold cabinet, provides a barrier of moving air across a door opening and reduces heat transfer by preventing the penetration of hot air. The simulation shows that there is the minimum speed and the best speed range of air curtain. The air curtain can not be formed when the speed is less than 1.5 m·s-1, while has a large spillover of cold air when it is greater than 3.0 m·s-1. From the above, the best speed of air curtain ranges from 2.6 m·s-1 to 3.0 m·s-1.

关键词： Energy utilization

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A new method for compensating phase-shifting error in phase measuring profilometry

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Dongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Southeast University (Natural Science Edition) 2010年第SUPPL. 1期40卷 302-307页

作者： Zhu, Lin Da, Feipeng Gai, Shaoyan Research Institute of Automation Southeast University Nanjing 210096 China Key Laboratory of Measurement and Control of Complex Systems of Engineering of Ministry of Edu. Southeast University Nanjing 210096 China

A new phase-shifting error compensating algorithm for phase-measuring profilometry is proposed. In this error detecting algorithm, it is supposed that sinusoidal fringe is projected to the plate, thus the phase differences between adjacent pixels are equal. Three adjacent phase points are taken as the research object. Combining the principle of phase compensation measurement, each phase of the point is presented as an equation containing the phase-shifting error. According to the characteristics that the phase differences between adjacent pixels are equal, an equation to calculate the phase-shifting error is constructed. Then the phase shifting error is taken into account in the original algorithm for error compensation. Simulation results show the inhibitory effect of the error compensation by using the novel algorithm. The proposed algorithm is also used for three-dimensional reconstruction. The final result shows that the new compensation algorithm is better than the original one obviously. This error compensating algorithm can effectively improve the accuracy of three-dimensional measurement.

关键词： Error compensation

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Particle swarm optimization and its application in multi-robot systems

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Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) 2013年第SUPPL.2期44卷 126-132页

作者： Ni, Chunbo Kong, Yifei Yang, Yuequan Cao, Zhiqiang Zhang, Tianping College of information Engineering Yangzhou University Yangzhou 225009 China State Key Laboratory of Management and Control for Complex Systems Institute of Automation Chinese Academy of Sciences Beijing 100190 China

Particle swarm optimization is a focus on queue control, path optimization, destination search, and so on in multiple robot systems, of which the main idea is that the optimization solution of swarm behaviors are to be obtained through iteration update of velocities and coordinate positions of particles. Based on analysis of particle swarm principle and of mechanism of its main parameters, comparative researches on particle swarm with genetic algorithm, ant colony algorithm, and neural network are given, respectively. Then a survey on research progresses of particle swarm optimization and relative modified new optimization algorithms applied in robot/multi-robot systems is given. Finally, the outlook of future work on particle swarm optimization applied in multi-robot systems under community perception networks is proposed.

关键词： Genetic algorithms

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Real-Time Generative Design of Diverse, "Truly" Optimized Structures With Controllable Structural complexities

SSRN

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SSRN 2024年

作者： Du, Zongliang Ma, Xinyu Hao, Wenyu Liang, Yuan Zhang, Xiaoyu Luo, Hongzhi Guo, Xu State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial Equipment Department of Engineering Mechanics Dalian University of Technology Dalian116023 China Ningbo Institute of Dalian University of Technology Ningbo315016 China Beijing Institute of Spacecraft System Engineering China Academy of Space Technology Beijing100094 China Beijing Institute of Astronautical Systems Engineering Beijing100076 China

Compared with traditional design methods, generative design significantly attracts engineers in various disciplines. In thiswork, howto achieve the real-time generative design of optimized structures with various diversities and controllable structural complexities is investigated. To this end, a modified Moving Morphable Component (MMC) method together with novel strategies are adopted to generate high-quality dataset. The complexity level of optimized structures is categorized by the topological invariant. By improving the cost function, the WGAN is trained to produce optimized designs with the input of loading position and complexity level in real time. It is found that, diverse designs with a clear load transmission path and crisp boundary, even not requiring further optimization and different from any reference in the dataset, can be generated by the proposed model. This method holds great potential for future applications of machine learning enhanced intelligent design. © 2024, The Authors. All rights reserved.

关键词： Cost functions

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Robust Control of Feeding Speed in Coal Seam Drilling Process Considering Borehole Friction

Robust Control of Feeding Speed in Coal Seam Drilling Proces...

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Chinese Automation Congress (CAC)

作者： Xiao Liu Luefeng Chen Chengda Lu Haipeng Fan Min Wu Witold Pedrycz School of Automation China University of Geosciences Wuhan China Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems School of Automation China University of Geosciences Engineering Research Center of Intelligent Technology for Geo-Exploration Ministry of Education Wuhan China Department of Electrical and Computer Engineering University of Alberta Edmonton AB Canada Systems Research Institute Polish Academy of Sciences Warsaw Poland Department of Computer Engineering Istinye University Istanbul Turkey

ISBN: (数字)9798350368604

ISBN: (纸本)9798350368611

During the coal seam drilling process, the drill string is subject to compressive deformation, compounded by unpredictable variations in formation hardness and borehole wall friction, leading to challenges in maintaining a stable feeding speed. This paper presents a novel approach by introducing uncertain parameters to describe the effects of formation hardness and borehole wall friction. Drill string axial movement model is modeled as a polyhedral system based on a lumped parameter representation. To meet industrial performance requirements, we design a robust $H_{\infty}$ controller to achieve consistent feeding speed control. Our simulation results demonstrate the controller's effectiveness in ensuring system stability despite fluctuations in formation hardness and drill string friction.

关键词： Drilling Robust control Friction Simulation Geology Velocity control Stability criteria Process control Coal Output feedback

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Adaptive Iterative Learning Control for Uncertain Delay systems Based on Model Matching Technique

Adaptive Iterative Learning Control for Uncertain Delay Syst...

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2011 American Control Conference (ACC)

作者： Haixia Su Yingmin Jia Junping Du Fashan Yu Seventh Research Division and the Department of Systems and Control Beihang University Beijing China Key Laboratory of Mathematics Informatics and Behavioral Semantics (LMIB) Ministry of Education SMSS Beihang University Beijing China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo Henan China

In this paper, an adaptive iterative learning control (ILC) scheme is proposed for trajectory tracking of uncertain delay systems based on model matching technique. The reference model is a delay system operating over in a finite time interval. An iterative model matching controller is designed and an iteration domain adaptive law is chosen to estimate the unknown parameters. It shows that the model matching technique can be applied in a straightforward method to ILC problem. A simulation example is included to illustrate the designed scheme.

关键词： Adaptation models Polynomials Adaptive systems Delay effects Delay systems

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H_∞ filtering with Diagonal Interacting Multiple Model Algorithm for Maneuvering Target Tracking

H_∞ filtering with Diagonal Interacting Multiple Model Algo...

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American Control Conference

作者： X. Fu Y. Jia J. Du J. Zhang W. Li X. Liu Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Beijing Key Laboratory of Intelligent Telecommunication Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunication school of Electronic and Information Engineering Beihang University (BUAA) Department of Automatic Beijing Information and Science of University

ISBN: (纸本)9781479901777

This paper is devoted to the problem of state estimate of discrete-time stochastic systems with Markov jump parameters. A robust algorithm-diagonal interacting multiple model algorithm based on H_∞ filtering (DIMMH) is presented for maneuvering target tracking when measurement noise is of unknown statistics. Extensive Monte Carlo simulations show the effectiveness and superiority of the proposed algorithm.

关键词： Maneuvering Target Tracking Markov jump parameters effectiveness Target tracking maneuvering target State estimation Filtration tracking Noise measurement Diagonal Monte Carlo technique

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