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Manipulation of Coherent Optical Propagation Based on Monolayer MoS2 Resonator

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Photonic Sensors 2019年第4期9卷 317-326页

作者： Huajun Chen School of Mechanics and Photoelectric Physics Anhui University of Science and TechnologyHuainan 232001China

Atomically thin two-dimensional semiconductor nanomaterials have attained considerable attention currently.We here theoretically investigate the phenomena of slow and superluminal light based on the MoS2 resonator system driven by two-tone fields.Superluminal and ultraslow probe light without absorption can be obtained via manipulating the pump laser on-and off-resonant with the exciton frequency under different parameters regimes,respectively,of which the magnitude is larger than that in a carbon nanotube resonator.The bandwidth of the probe spectrum determined by the quality factor Q of MoS2 resonator is also presented.Furthermore,we also demonstrate the phenomenon of phonon induced transparency and show an optical transistor in the system.The all-optical device based on MoS2 resonator may indicate potential chip-scale applications in quantum information with the currently popular pump-probe technology.

关键词： MoS2 nanomechanical resonator fast and slow light optical transistor

An Analytical Study on Bistability of Fabry-Perot Semiconductor Optical Amplifiers

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Photonic Sensors 2016年第3期6卷 268-273页

作者： Gang WANG Shuqiang chen huajun YANG School of Physical Electronics University of Electronic Science and Technology of China Chengdu 610054 China

光 bistabilities 被认为为传感器应用程序有用。作为一台典型非线性的设备， Fabry-Perot 半导体在某些条件下面的光放大器(FPSOA ) 展览 bistability。在这篇论文，在 FPSOA 的双稳态的特征理论上被调查。把光紧张基于在这个事件之间... 详细信息

光 bistabilities 被认为为传感器应用程序有用。作为一台典型非线性的设备， Fabry-Perot 半导体在某些条件下面的光放大器(FPSOA ) 展览 bistability。在这篇论文，在 FPSOA 的双稳态的特征理论上被调查。把光紧张基于在这个事件之间的亚当斯关系我在和 z 独立的平均 intracavity 紧张我 av , 在 SOA 的双稳态的循环宽度的一个分析表达式被导出。数字模拟证实分析结果的精确性。

关键词：半导体光放大器稳态分析入射光强度光学双稳性非线性器件解析表达式稳态特性数值模拟

An energy consumption prediction approach of die casting machines driven by product parameters

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Frontiers of Mechanical Engineering 2021年第4期16卷 868-886页

作者： Erheng chen Hongcheng LI huajun CAO Xuanhao WEN State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China School of Advanced Manufacturing Engineering Chongqing University of Posts and TelecommunicationChongqing 400065China

Die casting machines,which are the core equipment of the machinery manufacturing industry,consume great amounts of energy.The energy consumption prediction of die casting machines can support energy consumption quota,process parameter energy-saving optimization,energy-saving design,and energy efficiency evaluation;thus,it is of great significance for Industry 4.0 and green manufacturing.Nevertheless,due to the uncertainty and complexity of the energy consumption in die casting machines,there is still a lack of an approach for energy consumption prediction that can provide support for process parameter optimization and product design taking energy efficiency into consideration.To fill this gap,this paper proposes an energy consumption prediction approach for die casting machines driven by product parameters.Firstly,the system boundary of energy consumption prediction is defined,and subsequently,based on the energy consumption characteristics analysis,a theoretical energy consumption model is established.Consequently,a systematic energy consumption prediction approach for die casting machines,involving product,die,equipment,and process parameters,is proposed.Finally,the feasibility and reliability of the proposed energy consumption prediction approach are verified with the help of three die casting machines and six types of products.The results show that the prediction accuracy of production time and energy consumption reached 91.64%and 85.55%,respectively.Overall,the proposed approach can be used for the energy consumption prediction of different die casting machines with different products.

关键词： die casting machine energy consumption prediction product parameters

OpenKG Chain:A Blockchain Infrastructure for Open Knowledge Graphs

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Data Intelligence 2021年第2期3卷 205-227页

作者： Huajun Chen Ning Hu Guilin Qi Haofen Wang Zhen Bi Jie Li Fan Yang College of Computer Science&AZFT Knowledge Engine Lab Zhejiang UniversityHangzhou 310058China Ontology Foundation Venture Drive#11-31Vision ExchangeSingapore 608526Singapore School of Computer Science and Engineering Southeast UniversityNanjing 211189China Intelligent Big Data Visualization Lab Tongji UniversityShanghai 200092China

The early concept of knowledge graph originates from the idea of the semantic Web,which aims at using structured graphs to model the knowledge of the world and record the relationships that exist between things.Currently publishing knowledge bases as open data on the Web has gained significant attention.In China,Chinese Information Processing Society of China(CIPS)launched the OpenKG in 2015 to foster the development of Chinese Open Knowledge Graphs.Unlike existing open knowledge-based programs,OpenKG chain is envisioned as a blockchain-based open knowledge infrastructure.This article introduces the first attempt at the implementation of sharing knowledge graphs on OpenKG chain,a blockchain-based trust network.We have completed the test of the underlying blockchain platform,and the on-chain test of OpenKG’s data set and tool set sharing as well as fine-grained knowledge crowdsourcing at the triple level.We have also proposed novel definitions:K-Point and OpenKG Token,which can be considered to be a measurement of knowledge value and user value.1,033 knowledge contributors have been involved in two months of testing on the blockchain,and the cumulative number of on-chain recordings triggered by real knowledge consumers has reached 550,000 with an average daily peak value of more than 10,000.For the first time,we have tested and realized on-chain sharing of knowledge at entity/triple granularity level.At present,all operations on the data sets and tool sets at ***,as well as the triplets at OpenBase,are recorded on the chain,and corresponding value will also be generated and assigned in a trusted mode.Via this effort,OpenKG chain looks forward to providing a more credible and traceable knowledge-sharing platform for the knowledge graph community.

关键词： Open knowledge graph Blockchain Decentralized distributed network Decentralized knowledge graph

Neural symbolic reasoning with knowledge graphs:Knowledge extraction,relational reasoning,and inconsistency checking

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Fundamental Research 2021年第5期1卷 565-573页

作者： Huajun Chen Shumin Deng Wen Zhang Zezhong Xu Juan Li Evgeny Kharlamov College of Computer Science Zhejiang UniversityHangzhou310027China Hangzhou Innovation Center Zhejiang UniversityHangzhou310000China AZFT Joint Lab for Knowledge Engine Hangzhou311121China Bosch Center for Artificial Intelligence Robert Bosch GmbHRenningen70465 StuttgartGermany SIRIUS Research Center University of OsloOsloN-0316Norway

Knowledge graphs(KGs)express relationships between entity pairs,and many real-life problems can be formulated as knowledge graph reasoning(KGR).Conventional approaches to KGR have achieved promising performance but still have some drawbacks.On the one hand,most KGR methods focus only on one phase of the KG lifecycle,such as KG completion or refinement,while ignoring reasoning over other stages,such as KG extraction.On the other hand,traditional KGR methods,broadly categorized as symbolic and neural,are unable to balance both scalability and interpretability.To resolve these two problems,we take a more comprehensive perspective of KGR with regard to the whole KG lifecycle,including KG extraction,completion,and refinement,which correspond to three subtasks:knowledge extraction,relational reasoning,and inconsistency checking.In addition,we propose the implementation of KGR using a novel neural symbolic framework,with regard to both scalability and interpretability.Experimental results demonstrate that our proposed methods outperform traditional neural symbolic models.

关键词： Neural symbolic reasoning Knowledge graph Knowledge extraction Relational reasoning Inconsistency checking

Controllable broadband multicolour single-mode polarized laser in a dye-assembled homoepitaxial MOF microcrystal

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Light(Science & Applications) 2020年第1期9卷 686-695页

作者： huajun He Yuanjing Cui Hongjun Li Kai Shao Banglin chen Guodong Qian State Key Laboratory of Silicon Materials Cyrus Tang Center for Sensor Materials and ApplicationsSchool of Materials Science and EngineeringZhejiang University310027 HangzhouChina Department of Chemistry University of Texas at San AntonioSan AntonioTX 78249USA Present address:Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological University21 Nanyang LinkSingapore 637371Singapore

Multicolour single-mode polarized microlasers with visible to near-infrared output have very important applications in photonic integration and multimodal biochemical sensing/imaging but are very difficult to realize.Here,we demonstrate a single crystal with multiple segments based on the host-guest metal-organic framework ZJU-68 hierarchically hybridized with different dye molecules generating controllable single-mode green,red,and nearinfrared lasing,with the lasing mode mechanism revealed by computational simulation.The segmented and oriented assembly of different dye molecules within the ZJU-68 microcrystal causes it to act as a shortened resonator,enabling us to achieve dynamically controllable multicolour single-mode lasing with a low three-colour-lasing threshold of ~1.72 mJ/cm^(2)(approximately seven times lower than that of state-of-the-art designed heterostructure alloys,as reported by Fan F et al.(Nat.Nanotechnol.10:796-803,2015)considering the single pulse energy density)and degree of polarization>99.9%.Furthermore,the resulting three-colour single-mode lasing possesses the largest wavelength coverage of ~186 nm(ranging from ~534 to ~720 nm)ever reported.These findings may open a new route to the exploitation of multicolour single-mode micro/nanolasers constructed by MOF engineering for photonic and biochemical applications.

关键词： polarization resonator mode

Explicit Multi-Symplectic Splitting Methods for the Nonlinear Dirac Equation

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Advances in Applied Mathematics and Mechanics 2014年第4期6卷 494-514页

作者： Yaming chen Songhe Song huajun Zhu Department of Mathematics and System Science and State Key Laboratory of High Performance Computing National University of Defense TechnologyChangsha 410073China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China

In this paper,we propose two new explicit multi-symplectic splitting methods for the nonlinear Dirac(NLD)equation.Based on its multi-symplectic formulation,the NLD equation is split into one linear multi-symplectic system and one nonlinear infinite Hamiltonian system.Then multi-symplectic Fourier pseudospectral method and multi-symplectic Preissmann scheme are employed to discretize the linear subproblem,respectively.And the nonlinear subsystem is solved by a symplectic scheme.Finally,a composition method is applied to obtain the final schemes for the NLD equation.We find that the two proposed schemes preserve the total symplecticity and can be solved explicitly.Numerical experiments are presented to show the effectiveness of the proposed methods.

关键词： Nonlinear Dirac equation multi-symplectic method splitting method explicit method

Thermoelectric enhancement of p-type Si_(80)Ge_(20) alloy via co-compositing of dual oxides:Respective regulation for power factor and thermal conductivity byβ-Ga_(2)O_(3) and SiO_(2) aerogel powders

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Journal of Advanced Ceramics 2023年第2期12卷 228-241页

作者： huajun LAI Ying PENG Mengfei WANG Runze SHI Junliang chen chengyan LIU Yifeng WANG Lei MIAO Haiqiao WEI Key Laboratory of Information Material Ministry of EducationGuangxi Key Laboratory of Information MaterialSchool of Materials Science and EngineeringGuilin University of Electronic TechnologyGuilin 541004China Guangxi Key Laboratory of Precision Navigation Technology and Application School of Information and CommunicationGuilin University of Electronic TechnologyGuilin 541004China School of Physical Science and Technology Guangxi UniversityNanning 530004China College of Materials Science and Engineering Nanjing Tech UniversityNanjing 210009China State Key Laboratory of Engines Tianjin UniversityTianjin 300072China

Si-based thermoelectric(TE)materials are exhibiting remarkable perspectives in self-energized applications with their special advantages.However,the relatively high total thermal conductivity(κ)prevents their TE enhancement.Here,a strategy of co-compositing dual oxides was implemented for enhancing the TE properties of p-type Si_(80)Ge_(20) bulks.Composited Ga2O_(3) was demonstrated to enhance the power factor(PF)due to the crystallization-induced effect of produced Ga by decomposition on SiGe matrix.Associating with compositing SiO_(2) aerogel(a-SiO_(2))powder,not only introduced the fine amorphous inclusions and decreased the grain size of host matrix,but also various nano morphologies were formed,i.e.,nano inclusions,precipitations,twin boundaries(TBs),and faults.Combining with the eutectic Ge,hierarchical scattering centers impeded the phonon transport comprehensively(decreasing the phonon group velocity(a v)and relaxation time)for reducing the lattice-induced thermal conductivity(lκ).As a result,a minimumκof 2.38 W·m^(−1)·K^(−1) was achieved,which is significantly dropped by 32.6%in contrast with that of the pristine counterpart.Ultimately,a maximal dimensionless figure of merit(ZT)of 0.9 was achieved at 600℃,which is better than those of most corresponding oxide-composited Si-based bulks.

关键词： thermoelectric(TE)materials SiGe Ga_(2)O_(3) SiO_(2)aerogel(a-SiO_(2)) average velocity of sound hierarchical scattering

Multi-SymplecticWavelet Collocation Method for Maxwell’s Equations

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Advances in Applied Mathematics and Mechanics 2011年第6期3卷 663-688页

作者： huajun Zhu Songhe Song Yaming chen Department of Mathematics and System Science School of ScienceNational University of Defense TechnologyChangsha 410073China

In this paper,we develop a multi-symplectic wavelet collocation method for three-dimensional(3-D)Maxwell’s equations.For the multi-symplectic formulation of the equations,wavelet collocation method based on autocorrelation functions is applied for spatial discretization and appropriate symplectic scheme is employed for time integration.Theoretical analysis shows that the proposed method is multi-symplectic,unconditionally stable and energy-preserving under periodic boundary conditions.The numerical dispersion relation is investigated.Combined with splitting scheme,an explicit splitting symplectic wavelet collocation method is also constructed.Numerical experiments illustrate that the proposed methods are efficient,have high spatial accuracy and can preserve energy conservation laws exactly.

关键词： Multi-symplectic wavelet collocation method Maxwell’s equations symplectic conservation laws