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Quasi-degenerate dark matter for DAMPE excess and 3.5 ke V line

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Science China(Physics,Mechanics & Astronomy) 2018年第10期61卷 30-35页

作者： Pei-hong gu School of Physics and Astronomy Shanghai Jiao Tong University

We propose a quasi-degenerate dark matter scenario to simultaneously explain the 1.4 TeV peak in the high-energy cosmic-ray electron-positron spectrum reported by the DAMPE collaboration very recently and the 3.5 keV X-ray line observed in galaxies clusters and from the Galactic centre and confirmed by the Chandra and NuSTAR satellites. We consider a dark S U（2）′× U（1）′ gauge symmetry under which the dark matter is a Dirac fermion doublet composed of two S U（2）′ doublets with non-trivial U（1 ）′ charges. At the one-loop level the two dark fermion components can have a mass split as a result of the dark gauge symmetry breaking. Through the exchange of a mediator scalar doublet the two quasi-degenerate dark fermdons can mostly annihilate into the electron-positron pairs at the tree level for explaining the 1.4 TeV positron anomaly, meanwhile, the heavy dark fermion can very slowly decay into the light dark fermion with a photon at the one-loop level for explaining the 3.5 keV X-ray line. Our dark fermions can be also verified in the direct detection experiments.

关键词： dark matter DAMPE excess 3.5 ke V line

Dynamical Evolution of Highway Traffic Flow:from Microscopic to Macroscopic

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Chinese Physics Letters 1997年第3期14卷 202-205页

作者： WANG Bing-hong HUI Pak-ming gu guo-qing Department of Modern Physics and The Center of Nonlinear Science University of Science and Technology of ChinaHefei 230026 Department of Physics The Chinese University of Hong KongShatinNTHong Kong Department of System Engineering Shanghai University of Science and TechnologyShanghai 200093

In this paper,a derivation of the macroscopic mean field theory of the cellular automaton(CA)model of highway traffic flow starting from the microscopic dynamical point of view is *** from an equation describing the time evolution of the Boolean state variable at each site of the basic CA model,and using a two-site approximation for the multi-site correlation functions,a dynamical mapping between the macroscopic average speeds v(t+1)and v(t)at different time can be *** field results consistent with the simulation data are obtained by considering the attractors of the mapping and their corresponding basins.

关键词： dynamical macroscopic starting

A Novel Onboard-gateway-based Mechanism to Improve TCP Performance in Aeronautical Satellite Networks

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Chinese Journal of Aeronautics 2007年第3期20卷 260-265页

作者： gu ming ZHANG Jun School of Electronics and lnformation Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

The IP-based networks on aircraft serve to support Intemet services via satellites. However, in aeronautical satellite hybrid networks, the TCP protocol performance often deteriorates due to improper decreases and slow recovery of the congestion window. This paper proposes a window size determination and notification mechanism, onboard-gateway-based mechanism （OGBM）, which is based on the onboard gateway in the networks on aircraft. A cross-layer approach is adopted by the onboard gateway to obtain the satellite link bandwidth information. And then, by the gateway, through changing the receiver＇s advertised window field in ACK packets, TCP sources are notified of the window size of each TCP source calculated on the ground of bandwidth delay product and flow numbers. The mechanism is able to avoid improper changes of TCP window and serve multiple users. Simulation results show that the mechanism with the fairness index close to l improves TCP performance in aeronautical satellite networks.

关键词： congestion control TCP gateway aeronautical satellite network

Coherent Control of Photon Transmission in a Coupled-Resonator Waveguide Embedded in a Semiconductor Quantum Dot

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Chinese Physics Letters 2012年第10期29卷 58-61页

作者： gu Ling-ming School of Electrical Engineering&Information Anhui University of TechnologyMaanshan 243002

We theoretically investigate the single photon transport in a coupled resonator waveguide embedded in a semiconductor quantum dot with a V-type *** transmission and reflection amplitudes are obtained by using a discrete coordinates *** is shown that the photon transport properties can be controlled by the energy detuning between the two excited states of the V-type system,and the coupling strength between the photon and the V-type *** also compare the single photon transport properties in the waveguide with sinusoidal and linear dispersion relations.

关键词： waveguide tuning resonator

NASTCNN: a spatio-temporal convolutional neural network with non-local attention mechanism for image-induced brain activity pattern recognition

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Optoelectronics Letters 2025年

作者： TAN Xiangxin SHAO mingxiong ZENG Ke gu Yue School of Computer Science and Engineering， Tianjin University of Technology Engineering Research Center of Learning-Based Intelligent System (Ministry of Education)， Tianjin University of Technology Krembil Research Institute， University Health Network

Deciphering the brain’s visual processing mechanisms has always been a hot topic. Using neural signal patterns to predict the corresponding external visual stimuli is crucial in understanding the interaction of real visual scenes. There are some challenges in the study of image-induced brain activity pattern recognition based on electroencephalogram (EEG)， e.g. how to fully utilize the effective features of EEG signals to improve the classification， and how the frequency and the length of EEG effect the model performance. We design an experimental paradigm that minimizes the interaction between visual stimuli， and propose a spatio-temporal convolutional neural network with non-local attention mechanism (NASTCNN) for image-induced brain activity pattern recognition. The framework utilizes non-local feature extraction operations to realize global information interaction between EEG signals over long distances and enhance the feature expression of some important information. Our model achieves the best performance on both MNIST-EEG and ImageNet-EEG datasets. The classification results are 24.00% and 50.10% respectively， higher than the random probability. We also analyze the effects of different EEG frequency bands and time subsequences of different lengths on the classification performance and which brain regions are activated over time. The results show that when full frequency band and entire length sequence are selected， the classification result is optimal. The occipital region is essential for processing visual tasks， and the temporal region and some frontal regions also play important role in the later stage of visual decoding. This research can help us better understand the visual processing mechanism of the brain.

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Interference effects of two and three super-tall buildings under wind action

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Acta Mechanica Sinica 2011年第5期27卷 687-696页

作者： ming gu Zhuang-Ning Xie State Key Lab for Disaster Reduction in Civil Engineering Tongji University 200092 Shanghai China Department of Civil Engineering South China University of Technology 510641 Guangzhou China

Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data *** this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure ***,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors.

关键词： Super-tall building · Wind force and response · Interference effect · Wind tunnel test

Facile method to synthesize oleic acid-capped magnetite nanoparticles

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Chinese Chemical Letters 2010年第2期21卷 179-182页

作者： Wang, Chun Yu hong, Jian ming Chen, Gong Zhang, Yu gu, Ning Southeast Univ State Key Lab Bioelect Nanjing 210096 Peoples R China Southeast Univ Jiangsu Key Lab Biomat & Devices Nanjing 210096 Peoples R China Southeast Univ Sch Chem & Chem Engn Nanjing 210096 Peoples R China Nanjing Univ Ctr Mat Anal Nanjing 210096 Peoples R China Nanjing Univ TCM Affiliated Hosp Nanjing 210029 Peoples R China

We described a simple one-step process for the synthesis of oleic acid-capped magnetite nanoparticles using the dimethyl sulfoxide(DMSO) to oxidize the precursor Fe^(2+) at 140℃.By adjusting the alkalinity of the reaction system,magnetite nanoparticles with two sizes of 4 and 7 nm could be easily *** the magnetite nanoparticles coated by oleate were well-monodispersed in organic solvent.

关键词： Magnetite nanoparticles Monodisperse Synthesis

Across-wind loads and effects of super-tall buildings and structures

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Science China(Technological Sciences) 2011年第10期54卷 2531-2541页

作者： gu ming QUAN Yong State Key Laboratory of Disaster Reduction in Civil Engineering Tongji University Shanghai 200092 China

Across-wind loads and effects have become increasingly important factors in the structural design of super-tall buildings and structures with increasing height. Across-wind loads and effects of tall buildings and structures are believed to be excited by inflow turbulence, wake, and inflow-structure interaction, which are very complicated. Although researchers have been focusing on the problem for over 30 years, the database of across-wind loads and effects and the computation methods of equivalent static wind loads have not yet been developed, most countries having no related rules in the load codes. Research results on the across-wind effects of tall buildings and structures mainly involve the determination of across-wind aerodynamic forces and across-wind aerodynamic damping, development of their databases, theoretical methods of equivalent static wind loads, and so on. In this paper we first review the current research on across-wind loads and effects of super-tall buildings and structures both at home and abroad. Then we present the results of our study. Finally, we illustrate a case study in which our research results are applied to a typical super-tall structure.

关键词： super-tall building and structure across-wind aerodynamic force across-wind aerodynamic damping across-wind effects across-wind quivalent static wind loads case study

Design and fabrication of a new fluorescence enhancement system of silver nanoparticles-decorated aligned silver nanowires

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Rare Metals 2019年第12期38卷 1178-1186页

作者： Jian-Chao Wang hong-Sheng Luo ming-Hai Zhang Xi-hong Zu Jie Zhang Yu-Xin gu guo-Bin Yi School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China guangdong Provincial Key Laboratory of Advanced Coatings Research and Development China National Electric Apparatus Research Institute Co.Ltd.Guangzhou 510300China

A new substrate,aligned Ag nanowires decorated with silver nanoparticle composite structure(AgNWs@AgNPs),was fabricated to investigate metalenhanced fluorescence(MEF) and its *** new composite structure was fabricated via a three-phase interface assembly method followed by SnCl2 sensitization and AgNO3 reduction *** size and distribution of the nanoparticles on silver nanowires increased with the sensitization and reduction *** formation of AgNPs on the surfaces of AgNWs was confirmed by multiple characterization methods including scanning electron microscopy(SEM),transmission electron microscope(TEM),atomic force microscopy(AFM) and X-ray diffraction(XRD).The results show that the fluorescence intensity of the poly(3-hexylthiophene)(P3HT) on the composite structure was greatly enhanced compared with that on bare glass substrate,and the intensity increased with the increase in particle sizes and *** mechanism was basedo n the increase in excitation rate and the radiation decay *** new type of substrate could serve as a good and efficient MEF substrate for high-performance fluorescence-based devices.

关键词： Fluorescence enhancement Aligned Ag nanowires Self-assembly Mechanism