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Controlling the motion of solitons in BEC by a weakly periodic potential

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Chinese Physics B 2009年第3期18卷 939-945页

作者：奚玉东王登龙何章明丁建文 Department of Physics and key laboratory of Low Dimensional materials & application technology of Ministry of Education Xiangtan University

By developing multiple-scale method combined with Wentzel-Kramer-Brillouin expansion, this paper analytically studies the modulating effect of weakly periodic potential on the dynamical properties of the Dose-Einstein condensates （BEC） trapped in harmonic magnetic traps. A black-grey soliton transition is observed in the BEC trapped in harmonic magnetic potential, due to the weakly periodic potential modulating effect. Meanwhile, it finds that with the slight increase of the weakly periodic potential strength, the velocity of the soliton decreases, while its width firstly decreases then increases, a minimum exists there. These results show that the amplitude, velocity, and width of matter solitons can be effectively managed by means of a weakly periodic potential

关键词： Bose Einstein condensates solitons modulating effect

Effects of W Addition on the Electrochemical Behaviour and Passive Film Properties of Fe-based Amorphous Alloys in Acetic Acid Solution

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Acta Metallurgica Sinica(English Letters) 2018年第10期31卷 1098-1108页

作者： Dan-Dan Liang Xian-Shun Wei Chun-Tao Chang Jia-Wei Li Yong Wang Xin-Min Wang Jun Shen School of materials Science and Engineering Tongji University key laboratory of Magnetic materials and Devices Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences zhejiang Province key laboratory of Magnetic materials and application technology Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences School of Mechanical Science and Engineering Northeast Petroleum University

The electrochemical behaviour and passive film properties of Fe-Cr-Mo-W-C-B-Y amorphous alloys in acetic acid solution were investigated. The potentiodynamic polarisation and Nyquist curves demonstrated that W addition signifi- cantly enhanced the corrosion resistance. Mott-Schottky plots and angle-resolved X-ray photoelectron spectra indicated that passive films with different W contents exhibited dipolar （p-n） semiconducting characteristics separated by fiat-band potentials. The outer and inner oxide layers of the passive films were modified by reducing the acceptor and donor densities. Moreover, W addition favoured the formation of a thicker and more stable passive film to inhibit the dissolution of alloy elements.

关键词： Amorphous alloy XPS Mott-Schottky measurement Passive film Semiconducting property Chemical ingredient

The Internet of Things under Federated Learning:A Review of the Latest Advances and applications

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Computers, materials & Continua 2025年第1期82卷 1-39页

作者： Jinlong Wang Zhenyu Liu Xingtao Yang Min Li Zhihan Lyu School of Information and Control Engineering Qingdao University of TechnologyQingdao260043China Anhui Province key laboratory of Intelligent Building&Building Energy Saving Anhui Jianzhu UniversityHefei230000China Department of Game Design Uppsala UniversityUppsala75310Sweden

With the rapid development of artificial intelligence,the Internet of Things(IoT)can deploy various machine learning algorithms for network and application *** the IoT environment,many sensors and devices generatemassive data,but data security and privacy protection have become a serious *** learning(FL)can achieve many intelligent IoT applications by training models on local devices and allowing AI training on distributed IoT devices without data *** review aims to deeply explore the combination of FL and the IoT,and analyze the application of federated learning in the IoT from the aspects of security and privacy *** this paper,we first describe the potential advantages of FL and the challenges faced by current IoT systems in the fields of network burden and privacy ***,we focus on exploring and analyzing the advantages of the combination of FL on the Internet,including privacy security,attack detection,efficient communication of the IoT,and enhanced learning *** also list various application scenarios of FL on the ***,we propose several open research challenges and possible solutions.

关键词： Federated learning Internet of Things sensors machine learning privacy security

Local leakage current behaviours of BiFeO_3 films

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Chinese Physics B 2011年第11期20卷 493-498页

作者：邹成陈斌朱小健左正笏刘宜伟陈远富詹清峰李润伟 State key laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China key laboratory of Magnetic materials and Devices Ningbo Institute of Material Technology and EngineeringChinese Academy of Sciences zhejiang Province key laboratory of Magnetic materials and application technology Ningbo Institute of Material Technology and EngineeringChinese Academy of Sciences

The leakage current behaviours of polycrystalline BiFeO3 thin films are investigated by using both conductive atomic force microscopy and current-voltage characteristic measurements. The local charge transport pathways are found to be located mainly at the grain boundaries of the films. The leakage current density can be tuned by changing the post-annealing temperature, the annealing time, the bias voltage and the light illumination, which can be used to improve the performances of the ferroelectric devices based on the BiFeOa films. A possible leakage mechanism is proposed to interpret the charge transports in the polycrystalline BiFeO3 films.

关键词： polycrystalline BiFeO3 thin films local leakage current conductive atomic force microscopy

Improved photovoltaic effects in Mn-doped BiFeO3 ferroelectric thin films through band gap engineering

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Chinese Physics B 2017年第6期26卷 401-405页

作者：阎堂柳陈斌刘钢牛瑞鹏尚杰高双薛武红金晶杨九如李润伟 School of materials Science and Engineering Shanghai University key laboratory of Magnetic materials and Devices Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences zhejiang Provincial key laboratory of Magnetic materials and application technology Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences Electrical Engineering College Heilongjiang University

As a low-bandgap ferroelectric material, BiFeO3 has gained wide attention for the potential photovoltaic applications,since its photovoltaic effect in visible light range was reported in 2009. In the present work, Bi（Fe, Mn）O3thin films are fabricated by pulsed laser deposition method, and the effects of Mn doping on the microstructure, optical, leakage,ferroelectric and photovoltaic characteristics of Bi（Fe, Mn）O3 thin films are systematically investigated. The x-ray diffraction data indicate that Bi（Fe, Mn）O3 thin films each have a rhombohedrally distorted perovskite structure. From the light absorption results, it follows that the band gap of Bi（Fe, Mn）O3 thin films can be tuned by doping different amounts of Mn content. More importantly, photovoltaic measurement demonstrates that the short-circuit photocurrent density and the open-circuit voltage can both be remarkably improved through doping an appropriate amount of Mn content, leading to the fascinating fact that the maximum power output of ITO/BiFe（0.7）Mn（0.3）O3/Nb-STO capacitor is about 175 times higher than that of ITO/BiFeO3/Nb-STO capacitor. The improvement of photovoltaic response in Bi（Fe, Mn）O3 thin film can be reasonably explained as being due to absorbing more visible light through bandgap engineering and maintaining the ferroelectric property at the same time.

关键词： band gap engineering BiFeO3 Mn doping ferroelectric photovoltaic effect

The magnetization reversal behaviour for SmCo_(6.8)Zr_(0.2) and SmCo_(6.8)Zr_(0.2)/α-(Fe,Co) nanocrystalline magnets at low temperature

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Chinese Physics B 2010年第6期19卷 528-533页

作者：刘壮陈仁杰李东闫阿儒 zhejiang Province key laboratory of Magnetic materials and application technology Ningbo Institute of Material Technology & EngineeringChinese Academy of Sciences Institute of Solid State Physics Chinese Academy of Sciences

This paper reports that the SmCo6.8Zr0.2 nanocrystalline permanent magnets and SmCo6.8Zr0.2/a-（Fe,Co） nanocomposite permanent magnets are successfully produced by mechanical alloying and subsequently annealing at 700℃ for 10 minutes. The x-ray diffraction results show that the phase structure of SmCo6.8Zr0.2 nanocrystalline permanent magnets is composed of SmCo7 phase and SmCo6.8Zr0.2/a-（Fe,Co） nanocomposite permanent magnets is composed of SmCo7 and a-（Fe,Co） phases. The mechanism of magnetization reversal is mainly controlled by inhomogeneous domain wall pinning in SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-（Fe,Co） magnets. The inter-grain exchange interaction at low temperature is investigated, which shows that the inter-grain exchange interaction of SmCo6.8Zr0.2/a-（Fe,Co） magnets increases greatly by the decrease of the measured temperature. According to Amirr-H/Hcj, Amrev-H/Hcj and Xirr-H/Hcj curves at room temperature and 100 K, the changes of irreversible and reversible magnetization behaviours of SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-（Fe,Co） magnets with the decreasing temperature are analysed in detail. The magnetic viscosity and the activation volume of SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-（Fe,Co） magnets at different temperatures are also studied.

关键词： nanocrystalline magnets coercivity mechanism inter-grain exchange coupling magne- tization reversal behaviour

bio-based and biodegradable Electrospun Fibers Composed of Poly(L-lactide) and Polyamide 4

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Chinese Journal of Polymer Science 2020年第1期38卷 53-62,I0006页

作者： Tao Chen Guo-Cheng Zhong Yuan-Ting Zhang Li-Ming Zhao Yong-Jun Qiu School of materials Science and Engineering East China University of Science and TechnologyShanghai 200237China key laboratory of bio-based Material Engineering of China National Light Industry Council Shanghai200237China Shanghai key laboratory of Advanced polymeric materials Shanghai200237China School of biotechnology East China University of Science and TechnologyShanghai200237China

Novel bio-based and biodegradable block copolymers were synthesized by "click" reaction between poly(L-lactide)(PLLA) and polyamide 4(PA4). Upon tuning the molar mass of PLLA block, the properties of copolymers and electrospun ultrafine fibers were investigated and compared with those of PLLA and PA4 blends. PLLA and PA4 were found incompatible and formed individual crystalline regions, along with reciprocal inhibition in crystallization. Electrospun fibers were highly hydrophobic, even if hydrophilic PA4 was the rich component. The crystallinity of either PLLA or PA4 decreased after electrospinning and PLLA-rich as-spun fibers were almost amorphous. Immersion tests proved that fibers of block copolymers were relatively homogeneous with micro-phase separation between PLLA and PA4. The fibrous structures of copolymers were different from those of the fibers electrospun from blends, for which sheath-core structure induced by macro-phase separation between homopolymers of PLLA and PA4 was confirmed by TEM, EDS, and XPS.

关键词： Poly(L-lactide) Polyamide 4 "Click"reaction Electrospinning Fiber

Macro-mechanics and Microstructure of Nanomaterial-modified Geopolymer Concrete: A Comprehensive Review

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Journal of Wuhan University of technology(materials Science) 2025年第1期40卷 204-214页

作者： WANG Tao FAN Xiangqian GAO Changsheng QU Chiyu The National key laboratory of Water Disaster Prevention Nanjing Hydraulic Research InstituteNanjing 210024China Southern Marine Science and Engineering Guangdong laboratory(Guangzhou) Guangzhou 511458China School of Water Conservancy and Transportation Zhengzhou UniversityZhengzhou 450001China

We have described in detail the effects of nano-SiO_(2),nano-CaCO_(3),carbon nanotubes,and nano-Al_(2)O_(3) on geopolymer concrete from the perspectives of macro mechanics and *** existing research results show that the mechanism of nano-materials on geopolymer concrete mainly includes the filling effect,nucleation effect,and bridging effect,the appropriate amount of nano-materials can be used as fillers to reduce the porosity of geopolymer concrete,and can also react with Ca(OH)2 to produce C-S-H gel,thereby improving the mechanical properties of geopolymer *** optimum content of nano-SiO_(2) is between 1.0%and 2.0%.The optimum content of nano-CaCO_(3) is between 2.0%and 3.0%.The optimum content of carbon nanotubes is between 0.1%and 0.2%.The optimum content of nano-Al_(2)O_(3) is between 1.0%and 2.0%.The main problems existing in the research and application of nanomaterial-modified geopolymer concrete are summarized,which lays a foundation for the further application of nanomaterial in geopolymer concrete.

关键词： nanomaterials low carbon geopolymer concrete macro-mechanics microstructure

SYNTHESIS,SELF-ASSEMBLY AND RESPONSIVE PROPERTIES OF PEG-b-PDMAEMA-b-PMMAzo TRIBLOCK COPOLYMERS

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Chinese Journal of Polymer Science 2013年第5期31卷 833-840页

作者： Yao-hui Xing 林绍梁林嘉平 Xiao-hua He Shanghai key laboratory of Advanced polymeric materials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and Technology Department of Chemistry East China Normal University

A novel amphiphilic copolymer poly（ethylene glycol）-block-poly（N,N-dimethylamino-2-ethylmethacrylate）-block- poly[6-（4-methoxy-azobenzene-4＇-oxy） hexyl methacrylate] （PEG-b-PDMAEMA-b-PMMAzo） was prepared by ATRP polymerization. The self-assembly and responsive behaviors were investigated by SEM, TEM, LLS and UV-Vis spectra. The results indicated that the copolymers can self-assemble into spherical structures in aqueous media. The aggregate size can be tuned by pH and temperature. The trans-cis isomerization behavior of the formed aggregates was also examined. Upon irradiation with a linear polarized light, the elongation degree of the aggregates was increased with the irradiation time.

关键词： zobenezene Copolymer Self-assemble Responsive.