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Chinese Physics B 2021年第10期30卷 470-475页

作者： bin liu Hong Zhou School of Physics and Electronics Hunan UniversityChangsha 410082China

We present a controlled,stepwise formation of layered semiconductor Bi_(2)O_(2)Se thin films prepared via the vapour process by annealing topological insulator Bi_(2)Se3 thin films in low oxygen atmosphere for different *** based on Bi_(2)O_(2)Se thin film show a responsivity of 1.7×10^(4) A/W at a wavelength of 980 ***-effect transistors based on Bi_(2)O_(2)Se thin film exhibit n-type behavior and present a high electron mobility of 17 cm^(2)/V·*** addition,the electrical properties of the devices after 4 months keeping in the air shows little change,implying outstanding air-stability of our Bi_(2)O_(2)Se thin *** the obtained results,it is evident that low oxygen annealing is a surprisingly effective method to fabricate Bi_(2)O_(2)Se thin films for integrated optoelectronic applications.

关键词： thin films Bi_(2)Se_(3) vapor-phase deposition photodetector Bi_(2)O_(2)Se

Making fully printed perovskite solar cells stable outdoor with inorganic superhydrophobic coating

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Journal of Energy Chemistry 2020年第11期29卷 332-338页

作者： Jianqiang Luo Hong bin Yang Mingxiang Zhuang Shujuan liu Liang Wang bin liu State Key Laboratory of Nuclear Resources and Environment.East China University of Technology.Nanchang 330013 JiangxiChina School of Chemical&Biomedical Engineering(SCBE) Nanyang Technological University62 Nanyang DriveSingapore 637459Singapore Integrated Computational Materials Research Centre Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China

Outdoor environment including moisture, dust, UV, oxygen and thermal stress(repeated heating-cooling)is devastating to perovskite solar cells(PSCs). Here, we demonstrate a new strategy to make fully printed PSCs stable with maximum power output in outdoor environment by coating them with a porous hydrophobic inorganic layer. After coating, the PSCs can maintain superior stability of more than 150 days of outdoor storage, 240 h of continuous operation at the maximum power output point in ambient air with relative humidity as high as ~80%, and stable operation for more than 10 h under raining condition. ANSYS simulation shows that the thin and porous nature of the inorganic coating layer offers much better heat dissipation than conventional encapsulation methods using glasses attached by photocurable epoxy. A similar thermal expansion coefficient of the inorganic encapsulation material with the solar cell substrate can also prevent it from cracking after repeated heating-cooling cycles. All of these merits resulted from our encapsulation method endow the perovskite solar cells with the real outdoor working capability.

关键词： Perovskite solar cells Inorganic encapsulation Heat dissipation Outdoor stability

Hidden flow structures in compressible mixing layer and a quantitative analysis of entrainment based on Lagrangian method

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Journal of Hydrodynamics 2019年第2期31卷 256-265页

作者： Geng Liang bin Yu bin Zhang Hui Xu Hong liu School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

The compressible mixing layer is an important physical model to describe the mixing enhancement in scramjet *** downstream coherent structures are normally regarded as the main contribution of the entrainment in the compressible mixing *** this study,three cases of the compressible mixing layer of convective Mach number Ma=0.4 are numerically simulated through the Lagrangian coherent structure(LCS)method to show that the entrainment process in the compressible mixing layer is closely related to the upstream hidden structures termed as the"cn train me nt fbnnation structures^^.The entrainment fbrmatio n structures consist of a series of inclined control bodies that are identical and nested to one another upstream the compressible mixing *** combination with the separation of the flow properties of coherent structures,the entrainment characteristics in the compressible mixing layer can be evaluated by the inclined control bodies of the upstream entrainment formation structures in the upper and lower ***,with the quantitative analysis of the spatial position of the upstream coherent structure,the entrainment ratio is *** study of the entrainment formation and its characteristics helps the effective control of the entrainment performance in the compressible mixing layer.

关键词： Compressible mixing layer Lagrangian coherent structure(LCS) finite-time Lyapunov exponent(FTLE)

Influence of cross correlation step length on the surface stress of thin laser cladding Fe314 alloy coatings

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International Journal of Minerals,Metallurgy and Materials 2012年第6期19卷 549-554页

作者： bin liu Shi-yun Dong bin-shi Xu Peng He State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin 150001 China National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China

To measure the surface stress of thin laser cladding coatings with Rayleigh waves based on the cross correlation function, this pa- per introduced the influence of cross correlation step length on the stress measurement. Flat-shaped specimens made of laser cladding Fe314 alloy coatings were performed by static tensile tests, and Rayleigh wave signals were collected during the test process with an ultrasonic pulser and receiver instrument combined with two Rayleigh wave transducers. The difference in time of flight between two signals was de- termined based on the cross correlation function. The microstructure was observed by scanning electronic microscopy. The influence of the stress on the propagation velocity of Rayleigh waves and the relationship between the difference in time of flight and tensile stress under dif- ferent cross correlation step lengths were analyzed. The inhomogeneous deformation of the coatings affects the relationship between the dif- ference in time of flight and tensile stress; the stress measurement of the coatings is nearly constant with the increase of cross correlation step length when it attains one cycle.

关键词： iron alloys metal cladding laser cladding surface stress Rayleigh waves

Axial Assembled Correspondence Network for Few-Shot Semantic Segmentation

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IEEE/CAA Journal of Automatica Sinica 2023年第3期10卷 711-721页

作者： Yu liu bin Jiang Jiaming Xu School of Automation Science and Engineering South China University of TechnologyGuangzhou 510640 R&D Center of Precision Electronic Manufacturing Technology Guangzhou Institute of Modern Industrial Technologyand also with the High Performance Motor and Intelligent Control Engineering Technology Research Center of Guangdong ProvinceGuangzhou 511458China School of Automation Science and Engineering South China University of TechnologyGuangzhou 510640China IEEE

Few-shot semantic segmentation aims at training a model that can segment novel classes in a query image with only a few densely annotated support *** remains a challenge because of large intra-class variations between the support and query *** approaches utilize 4D convolutions to mine semantic correspondence between the support and query ***,they still suffer from heavy computation,sparse correspondence,and large *** propose axial assembled correspondence network(AACNet)to alleviate these *** key point of AACNet is the proposed axial assembled 4D kernel,which constructs the basic block for semantic correspondence encoder(SCE).Furthermore,we propose the deblurring equations to provide more robust correspondence for the aforementioned SCE and design a novel fusion module to mix correspondences in a learnable *** on PASCAL-5~i reveal that our AACNet achieves a mean intersection-over-union score of 65.9%for 1-shot segmentation and 70.6%for 5-shot segmentation,surpassing the state-of-the-art method by 5.8%and 5.0%respectively.

关键词： Artificial intelligence computer vision deep convolutional neural network few-shot semantic segmentation

Synthesis and luminescent properties of Ba_(3)Y_(3.88)Gd_(0.12)O_(9):Eu^(3+) phosphors with enhanced red emission

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Journal of Rare Earths 2022年第4期40卷 534-540,I0001页

作者： Guiyuan liu bin liu Jinkai Li Zongming liu School of Materials Science and Engineering University of JinanJinan 250022China

In this work,the Gd^(3+)/Eu^(3+) activated Ba_(3)Y_(4)O_(9)(BYO)phosphors were successfully synthesized via coprecipitation method at 1400℃.The precursor composition,crystal structure stability,microscopic morphology,photoluminescence(PL)/photoluminescence excitation(PLE)spectra and fluorescence attenuation analysis of the phosphors are discussed in *** chemical composition of the precursor was determined by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetry(TG)analysis;According to field emission-scanning electron microscopy(FE-SEM)analysis,it is found that the particle size of phosphor is uniform and the agglomeration is *** to PL/PLE spectra analysis,Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) phosphors has the strongest excitation band at 260 nm and the strongest emission band at 614 nm,and the fluorescence intensity of Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) is higher than that of Ba_(3)Y^(3.4)Eu^(0.6)O_(9).The quenching concentration of Eu^(3+)in Ba_(3)Y_(3.88–4x)Eu_(4x)Gd_(0.12)O_(9) phosphors is x=0.15 and the mechanism of quenching concentration of Eu^(3+)is electric dipole-quadrupole type *** lifetime value of Ba_(3)Y_(3.88–4x)Eu_(4x)Gd_(0.12)O_(9)(x=0.15)phosphors is 0.686 ms and decreases with the increase of Eu^(3+)*** addition,the CIE chromaticity diagram of Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) phosphors is(0.66,0.34).Finally,the lamp beads assembled with Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) phosphors have an ideal luminous ***,the Ba_(3)Y_(3.88–4x)Eu_(4x)Gd_(0.12)O_(9) phosphors designed in this work may hopefully meet the requirements of various lighting and optical display applications.

关键词： Coprecipitation method Ba_(3)Y_(3.88)Gd_(0.12)O_(9):Eu^(3+)phosphor Luminescent property Rare earths

A credible traffic prediction method based on self-supervised causal discovery

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Science China(Information Sciences) 2024年第5期67卷 244-258页

作者： Dan WANG Yingjie liu bin SONG State Key Laboratory of Integrated Services Networks Xidian University

Next-generation wireless network aims to support low-latency, high-speed data transmission services by incorporating artificial intelligence(AI) technologies. To fulfill this promise, AI-based network traffic prediction is essential for pre-allocating resources, such as bandwidth and computing power. This can help reduce network congestion and improve the quality of service(QoS) for users. Most studies achieve future traffic prediction by exploiting deep learning and reinforcement learning, to mine spatio-temporal correlated variables. Nevertheless, the prediction results obtained only by the spatio-temporal correlated variables cannot reflect real traffic changes. This phenomenon prevents the true prediction variables from being inferred, making the prediction algorithm perform poorly. Inspired by causal science, we propose a novel network traffic prediction method based on self-supervised spatio-temporal causal discovery(SSTCD). We first introduce the Granger causal discovery algorithm to build a causal graph among prediction variables and obtain spatio-temporal causality in the observed data, which reflects the real reasons affecting traffic ***, a graph neural network(GNN) is adopted to incorporate causality for traffic prediction. Furthermore,we propose a self-supervised method to implement causal discovery to to address the challenge of lacking ground-truth causal graphs in the observed data. Experimental results demonstrate the effectiveness of the SSTCD method.

关键词： wireless network traffic prediction causal discovery self-supervised

Fully-Actuated System Approach Based Optimal Attitude Tracking Control of Rigid Spacecraft with Actuator Saturation

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Journal of Systems Science & Complexity 2022年第2期35卷 688-702页

作者： liu Gaoqi ZHANG Kai LI bin School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China

In this paper,a fully-actuated system approach(FASA)based control method is proposed for rigid spacecraft attitude tracking with actuator ***,a second-order fully-actuated form of spacecraft attitude error model is established by modified Rodrigues parameters(MRPs).The unknown total disturbance caused by inertial uncertainty and external disturbance is estimated by using extended state observer,then an FASA based controller is ***,a control parameterization method is adopted to optimize the parameter matrices of FASA based controller with the actuator ***,a numerical example is carried out to validate the effectiveness of the proposed scheme.

关键词： Full-actuated system approach modified Rodrigues parameters parameter optimization spacecraft attitude tracking

Tuning mechanical behaviors of highly entangled hydrogels with the random distribution of mobile entanglements

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 277-294页

作者： Jinlong liu Di LU bin CHEN Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Beijing System Design Institute of Electro-Mechanic Engineering Beijing 100854China Intelligent Robotic Research Center Zhejiang LaboratoryHangzhou 310027China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Hangzhou 311100China

Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low *** considering the evolution of randomly distributed entanglements within the polymer network upon mechanical stretches,we develop a constitutive theory to describe the large stretch behaviors of these *** the theory,we utilize a representative volume element(RVE)in the shape of a cube,within which there exists an averaged chain segment along each edge and a mobile entanglement at each *** employing an explicit method,we decouple the elasticity of the hydrogels from the sliding motion of their entanglements,and derive the stress-stretch relations for these *** present theoretical analysis is in agreement with experiment,and highlights the significant influence of the entanglement distribution within the hydrogels on their *** also implement the present developed constitutive theory into a commercial finite element software,and the subsequent simulations demonstrate that the exact distribution of entanglements strongly affects the mechanical behaviors of the structures of these ***,the present theory provides valuable insights into the deformation mechanism of highly entangled hydrogels,and can aid in the design of these hydrogels with enhanced performance.

关键词： highly entangled hydrogel constitutive theory entanglement gamma distribution

Novel design of photoelectrochemical device by dual BiVO4 photoelectrode with abundant oxygen vacancy

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Science Bulletin 2018年第16期63卷 1027-1028页

作者： Dong liu bin liu School of Chemical and Biomedical Engineering Nanyang Technological University Singapore 637459 Singapore

Solar-driven catalysis represents a promising strategy and an important approach to provide clean energy and renewable *** decades of research on solar-driven catalysis,scientists are now focusing on module design,mec... 详细信息

关键词：氧化还原作用模块设计催化作用设备高生产率催化剂设计变换效率工作机制