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Series expansion feasibility of singular integral in method of moments

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Journal of Systems Engineering and Electronics 2014年第3期25卷 386-392页

作者： jinzu ji Peilin Huang School of Aeronautic Science and Engineering Beihang University

When calculating electromagnetic scattering using method of moments （MoM）, integral of the singular term has a significant influence on the results. This paper transforms the singular surface integral to the contour integral. The integrand is expanded to Taylor series and the integral results in a closed form. The cut-off error is analyzed to show that the series converges fast and only about 2 terms can agree wel with the accurate result. The comparison of the perfect electric conductive （PEC） sphere＇s bi-static radar cross section （RCS） using MoM and the accurate method validates the feasibility in manipulating the singularity. The error due to the facet size and the cut-off terms of the series are analyzed in examples.

关键词： method of moments (MoM) singular term series cut-off error radar cross section (RCS).

Quantitative deformation measurements and analysis of the ferrite-austenite banded structure in a 2205 duplex stainless steel at 250 ℃

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Chinese Physics B 2018年第3期27卷 487-493页

作者： ji-Hua Liu School of Mechanical Engineering Tianjin UniversityTianjin 300354China Tianjin Key Laboratory of Modern Engineering Mechanics Tianjin UniversityTianjin 300354China

The deformation process of the microstructure in 2205 duplex stainless steel(DSS)under thermo-mechanical coupling at 250℃was investigated using digital image correlation(DIC).A thermal tension test of duplex stainless steel(2205DSS)with a banded structure was carded out to observe the initial deformation of the *** was found that inhomogeneous strain fields occurred primarily in *** maximum normal strain in austenite was almost pos-itive,while that in ferrite was almost *** addition,a thermal cyclic-loading test was conducted,and the strain field was characterized by *** heterogeneities were induced after 400 cycles,which spread within the austenite and at the phase boundaries with the load *** high tensile-strain regions were always located adjacent to regions of intense compressive *** on the strain matrix sum *** number,we found that hardening occurred in the early cycles followed by softening.

关键词： thermo-mechanical coupling duplex stainless steel digital image correlation(DIC)

LKLR: A Local Tangent Space-Alignment Kernel Least-Squares Regression Algorithm

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Tsinghua Science and Technology 2019年第4期24卷 389-399页

作者： Chao Tan Genlin ji the School of Computer Science and Engineering Southeast University the School of Computer Science and Technology Nanjing Normal University the School of Computer Science and Technology Nanjing Normal University

In the fields of machine learning and data mining, label learning is a nascent area of research, and within this paradigm, there is much room for improving multi-label manifold learning algorithms for high-dimensional data. Thus far, researchers have experimented with mapping relationships from the feature space to the traditional logical label space(using neighbors in the label space, for example, to predict logical label vectors from the feature space's manifold structure). Here we combine the feature manifold's and label space's local topological structures to reconstruct the label manifold. To achieve this, we use a nonlinear manifold learning algorithm to transform the local topological structure from the feature space to the label space. Our algorithm adopts a regularized leastsquares kernel method to realize the reconstruction process, employing an optimization function to find the best solution. Extensive experiments show that our algorithm significantly improves multi-label manifold learning in terms of learning accuracy and time complexity.

关键词： multi-label manifold learning local topological structure regularized least squares kernel method

Analytical modeling and simulation of porous electrodes: Li-ion distribution and diffusion-induced stress

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Acta Mechanica Sinica 2018年第1期34卷 187-198页

作者： Liang ji Zhansheng Guo Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University

A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion(Liion) diffusion, diffusion-induced stress(DIS), Butler–Volmer(BV) reaction kinetics, and size polydispersity of electrode particles are considered. The influence of BV reaction kinetics and concentration-dependent exchange current density(ECD) on concentration profile and DIS evolution are numerically investigated. BV reaction kinetics leads to a decrease in Li-ion concentration and DIS. In addition, concentrationdependent ECD results in a decrease in Li-ion concentration and an increase in DIS. Size polydispersity of electrode particles significantly affects the concentration profile and *** macroscopic state of charge(SOC) should consider the influence of the microscopic SOC values and mass fractions of differently sized particles.

关键词： New model of porous electrode Butler–Volmer reaction kinetics Size polydispersity Exchange current density Li-ion concentration distribution Diffusioninduced stress

Highly Stretchable,Compressible,Adhesive,Conductive Self-healing Composite Hydrogels with Sensor Capacity

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Chinese Journal of Polymer Science 2020年第11期38卷 1221-1229,I0007页

作者： ji-Jun Wang Qiang Zhang Xing-Xiang ji Li-Bin Liu State Key Laboratory of Biobased Material and Green Papermaking School of Chemistry and Pharmaceutical EngineeringQilu University of Technology(Shandong Academy of Sciences)Jinan 250353China

The design and fabrication of conductive hydrogels with high stretchability,compressibility,self-healing properties and good adhesion remains a significant *** have fabricated composite hydrogels by random polymerization of acrylic acid(AA)and dopamine(DA)in the presence of multi-walled carbon nanotubes(MWCNTs).The π-π interaction between DA and MWCNTs makes MWCNTs stably and homogenously dispersed in *** fabricated PAA-PDA/CNT composite hydrogels possess relatively high mechanical strength(maximum Youngzs modulus:800 kPa)and can be stretched to 1280%strain and compressed to 80%*** multiple hydrogen bonding formed between functional groups of PAA-PDA and MWCNTs can effectively dissipate energy and quickly achieve *** composite hydrogels also show good adhesion and can easily adhere to various inorganic or organic *** addition,the hydrogel reveals stable strain sensitivity and can be used as skin sensors.

关键词： Hydrogels Self-healing Conductivity Sensor

Multi-user quantum private comparison with scattered preparation and one-way convergent transmission of quantum states

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Science China(Physics,Mechanics & Astronomy) 2017年第9期60卷 7-16页

作者： TianYu Ye ZhaoXu ji College of Information & Electronic Engineering Zhejiang Gongshang University

Quantum private comparison(QPC) aims to accomplish the equality comparison of the secrets from different users without disclosing their genuine contents by using the principles of quantum mechanics. In this paper, we summarize eight modes of quantum state preparation and transmission existing in current QPC protocols first. Then, by using the mode of scattered preparation and one-way convergent transmission, we construct a new multi-user quantum private comparison(MQPC) protocol with two-particle maximally entangled states, which can accomplish arbitrary pair's comparison of equality amongK users within one execution. Analysis turns out that its output correctness and its security against both the outside attack and the participant attack are guaranteed. The proposed MQPC protocol can be implemented with current technologies. It can be concluded that the mode of scattered preparation and one-way convergent transmission of quantum states is beneficial to designing the MQPC protocol which can accomplish arbitrary pair's comparison of equality among K users within one execution.

关键词： multi-user quantum private comparison (MQPC) scattered preparation one-way convergent transmission

Boosting electrocatalytic nitrate reduction to ammonia via Cu_(2)O/Cu(OH)_(2)heterostructures promoting electron transfer

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Nano Research 2024年第6期17卷 4898-4907页

作者： jing Geng Sihan ji Anhui Province International Research Center on Advanced Building Materials School of Materials Science and Chemical EngineeringAnhui Jianzhu UniversityHefei 230601China Anhui Province Key Laboratory of Advanced Building Materials Anhui Jianzhu UniversityHefei 230601China School of Energy Materials and Chemical Engineering Hefei UniversityHefei 230601China

Electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NH_(3))offers a viable approach for sustainable NH_(3)production and environmental ***(Cu)possesses a distinctive electronic structure,which can augment the reaction kinetics of NO_(3)^(−)and impede hydrogen evolution reaction(HER),rendering it a promising contender for the electrosynthesis of NH_(3)from NO_(3)^(−).Nevertheless,the role of Cu_(2)O in copper-based catalysts still requires further investigation for a more comprehensive ***,the Cu_(2)O/Cu(OH)_(2)heterostructures are successfully fabricated through liquid laser irradiation using CuO nanoparticles as a *** and theoretical researches reveal that Cu_(2)O/Cu(OH)_(2)heterostructure exhibits enhanced electrocatalytic performance for NO_(3)^(−)to NH_(3)because Cu(OH)_(2)promotes electron transfer and reduces the valence state of Cu active site in Cu_(2)***−0.6 V(*** hydrogen electrode(RHE)),the NH_(3)yield reaches its maximum at 1630.66±29.72μg·h^(−1)·mgcat^(−1),while the maximum of Faraday efficiency(FE)is 76.95%±5.51%.This study expands the technical scope of copper-based catalyst preparation and enhances the understanding of the electrocatalytic mechanism of NO_(3)^(−)to NH_(3).

关键词： Cu_(2)O/Cu(OH)_(2)heterostructures electron transfer ammonia synthesis electrocatalysts nitrate

The Convergence of Set-Valued Scenario Approach for Downside Risk Minimization

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Journal of Systems Science & Complexity 2016年第3期29卷 722-735页

作者： ji Xiaodong ZHU Shushang Department of Economics College of BusinessHebei Normal University Department of Finance and Investment Sun Yat-Sen Business SchoolSun Yat-Sen University

Scenario approach is a widely used tool in portfolio risk management,however,it often runs into dilemma when determining the distribution of asset returns with insufficient information,which will be used to simulate the *** the quality of generated scenarios are not guaranteed even when the distribution of asset returns is known exactly.A set-valued scenario approach was proposed by Zhu,et al.(2015)as a possible *** a necessary supplement of the results proposed by Zhu,et al.(2015),this paper theoretically investigates the convergent property of the numerical solution based on the set-valued scenario approach under the condition that the underlying distribution is known.

关键词： Convergence downside risk portfolio risk management set-valued scenarios.

Controlling Thermal Conduction by Graded Materials

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Communications in Theoretical Physics 2018年第4期69卷 434-440页

作者： Qin ji ji-Ping Huang Department of Physics State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (MOE) Fudan University Shanghai 200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 China

Manipulating thermal conductivities are fundamentally important for controlling the conduction of heat at will. Thermal cloaks and concentrators, which have been extensively studied recently, are actually graded materials designed according to coordinate transformation approaches, and their effective thermal conductivity is equal to that of the host medium outside the cloak or concentrator. Here we attempt to investigate a more general problem: what is the effective thermal conductivity of graded materials? In particular, we perform a first-principles approach to the analytic exact results of effective thermal conductivities of materials possessing either power-law or linear gradation profiles. On the other hand, by solving Laplace's equation, we derive a differential equation for calculating the effective thermal conductivity of a material whose thermal conductivity varies along the radius with arbitrary gradation *** two methods agree with each other for both external and internal heat sources, as confirmed by simulation and experiment. This work provides different methods for designing new thermal metamaterials(including thermal cloaks and concentrators), in order to control or manipulate the transfer of heat.

关键词： thermal metamaterials graded materials effective thermal conductivity