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N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu yuan Yao zhang Xiaoyan zhang Junjie zhang Shen’gen zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis

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Interface materials for perovskite solar cells

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Rare Metals 2021年第11期40卷 2993-3018页

作者： Yi-Heng zhang yuan Li School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China

Perovskite solar cells exhibit great potential to become commercial photovoltaic technology due to their high power conversion efficiency,low cost,solution processability,and facile large-area device *** engineering plays a significant role to optimize device *** the anode in the inverted devices,this review introduces the progress on the modification of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)including chemical structure alteration,physical doping,and solution *** present the recent advances of dopant-free hole transport materials widely applied in mesoporous and conventional devices,outlining their innovation with novel molecular design concepts toward promising material properties,and device *** the cathode,various metal oxide and organic electron transport materials are covered and the different modification strategies and related mechanisms are *** importantly,simple synthesis process,inexpensive raw materials and highly reproducible photovoltaic performance are the main consideration for the design of all the interface ***,an outlook and some suggestions regarding the future interface engineering are proposed based on the summary of the current development status and working mechanism of interface materials.

关键词： Perovskite solar cells Interface Hole transport materials Electron transport materials PEDOT:PSS

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On the Mean Value of High-Powers of a Special Character Sum Modulo a Prime

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Computer Modeling in Engineering & Sciences 2023年第7期136卷 943-953页

作者： Xiaodan yuan Wenpeng zhang School of Mathematics Northwest UniversityXi’anChina

In this paper,we use the elementary methods,the properties of Dirichlet character sums and the classical Gauss sums to study the estimation of the mean value of high-powers for a special character sum modulo a prime,and derive an exact computational *** can be conveniently programmed by the“Mathematica”software,by which we can get the exact results easily.

关键词： Quadratic character the classical gauss sums the mean value of high-power computational formula

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Lanthanide doped lead-free double perovskites as the promising next generation ultra-broadband light sources

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Light(Science & Applications) 2022年第5期11卷 736-738页

作者： Li zhang Mingjian yuan Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Renewable Energy Conversion and Storage Center(RECAST)College of ChemistryNankai UniversityTianjinChina Haihe Laboratory of Sustainable Chemical Transformations TianjinChina

Efficient ultra-broadband emitter is realized by using lanthanide ion doping coupled with“DPs-in-glass composite”(DiG)*** synergy of self-trapped exciton together with the energy transition induce this ultra-broadba... 详细信息

关键词： structure. perovskite Lanthanide

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Development of DSP-Based Dynamic Signal Processing Module for Turbine Flowmeter

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第5期33卷 546-551页

作者： Liu yuan zhang Tianhong College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics

Traditional signal processing methods for turbine flowmeter are unable to solve the contradiction between the real-time performance and the accuracy during the aeroengine bench test or hardware in the loop(HIL)simulation of aeroengine control system.A dynamic flow measurement method based on cycle number of the flowmeter is *** a DSP-based multi-functional dynamic signal processing module for turbine flowmeter is built to validate the *** developed system can provide three types of output modes including PWM,frequency and D/*** the same time,the results can be displayed instantly with the module of serial communication interface to obtain dynamic flow signal with good *** results show that the stability of flow measurement is greatly improved with precision guaranteed and the real-time response reaches the maximum limit of turbine flowmeter.

关键词： turbine flowmeter DSP cycle-number filter dynamic flow measurement

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Statistics of breaking waves and its applications to estimation of air-sea fluxes (Ⅰ)——Theoretical models

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Science China Earth Sciences 2004年第1期47卷 78-85页

作者： zhang Shuwen yuan Yeli Key Laboratory of Marine Science and Numerical Modeling First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Key Laboratory of Marine Science and Numerical Modeling First Institute of Oceanography State Oceanic Administration Qingdao 266061 China

Wave breaking statistics, such as the whitecap coverage and average volume of broken seawater, are evaluated in terms of wave parameters by use of wave breaking model (yuan et al., 1988) taking the fifth order Stokes's wave as the analog of the original wave field. Based on the observed fact that breaking waves play an important role in the exchange of mass, momentum and energy between the atmosphere and the ocean, the influence of wave breaking on air-sea fluxes of heat and moisture is investigated. Theoretical expressions of bubble-volume flux and sea spray spectrum at the sea surface and models for bubble-induced and spray droplet-induced heat and moisture fluxes are established. This work can be taken as the basis for further understanding the mechanism of air-sea coupling and parameterization models.

关键词： wave breaking, bubble, spray droplet, heat flux, moisture flux.

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Deep image synthesis from intuitive user input:A review and perspectives

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Computational Visual Media 2022年第1期8卷 3-31页

作者： yuan Xue yuan-Chen Guo Han zhang Tao Xu Song-Hai zhang Xiaolei Huang College of Information Sciences and Technology the Pennsylvania State UniversityUniversity ParkPAUSA Department of Computer Science and Technology Tsinghua UniversityBeijingChinaand Beijing National Research Center for Information Science and Technology(BNRist)Tsinghua UniversityBeijingChina Google Brain Mountain ViewCAUSA Facebook Menlo ParkCAUSA.

In many applications of computer graphics,art,and design,it is desirable for a user to provide intuitive non-image input,such as text,sketch,stroke,graph,or layout,and have a computer system automatically generate photo-realistic images according to that *** classically,works that allow such automatic image content generation have followed a framework of image retrieval and composition,recent advances in deep generative models such as generative adversarial networks(GANs),variational autoencoders(VAEs),and flow-based methods have enabled more powerful and versatile image generation *** paper reviews recent works for image synthesis given intuitive user input,covering advances in input versatility,image generation methodology,benchmark datasets,and evaluation *** motivates new perspectives on input representation and interactivity,cross fertilization between major image generation paradigms,and evaluation and comparison of generation methods.

关键词： image synthesis intuitive user input deep generative models synthesized image quality evaluation

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Improved dynamic regret of distributed online multiple Frank-Wolfe convex optimization

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Science China(Information Sciences) 2024年第11期67卷 164-179页

作者： Wentao zhang Yang SHI Baoyong zhang Deming yuan School of Automation Nanjing University of Science and Technology Department of Mechanical Engineering University of Victoria

In this paper, we explore a distributed online convex optimization problem over a time-varying multi-agent network. The network aims to minimize a global loss function through local computation and communication with neighboring agents. To effectively handle the optimization problem which involves highdimensional and structural constraint sets, we develop a distributed online multiple Frank-Wolfe algorithm that circumvents the expensive computational cost associated with projection operations. The dynamic regret bounds are established as O(T1-γ+ HT) with the linear oracle number O(T1+γ), which depends on the horizon（total iteration number） T, the function variation HT, and the tuning parameter 0 < γ < *** particular, when the prior knowledge of HTand T is available, the bound can be enhanced to O（1 +HT）. Moreover, we explore the significant advantages provided by the multiple iteration technique and reveal a trade-off between dynamic regret bound, computational cost, and communication cost. Finally,the performance of our algorithm is validated and compared through the distributed online ridge regression problems with two constraint sets.

关键词： distributed online convex optimization multiple iterations Frank-Wolfe algorithm dynamic regret gradient tracking method

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Enhancing electrochemical performance of ultrasmall Fe_(2)O_(3)-embedded carbon nanotubes via combusting-induced high-valence dopants

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Journal of Materials Science & Technology 2023年第3期134卷 142-150页

作者： yuan Wang Tao zhang Jianfei Xiao Xiaobao Tian Shaojun yuan Low-carbon Technology and Chemical Reaction Engineering Lab College of Chemical EngineeringSichuan UniversityChengdu 610065China College of Architecture and Environment Sichuan UniversityChengdu 610065China

Doping is a reasonable solution to improve the electronic structure and surface properties of ***,we propose a rapid and simple methodology,flame synthesis,as an effective preparation strategy for incorporating high-valence metal ions(Ti^(4+),Sn^(4+),and Zr^(4+))into ultrasmall Fe_(2)O_(3)on carbon nanotube support(i.e.,M-FeO-CNT).The resulting materials exhibit not only a boosted Na+adsorption as shown by density functional theory(DFT)calculations,but also display an increased oxygen *** electrochemical activity and charge transfer efficiency of Fe 2 O 3 can be improved by reasonably sub-stituting Fe 3+with Ti^(4+),Sn^(4+),and Zr^(4+).The electrochemical investigation of Ti-doped Fe 2 O 3(Ti-FeO-CNT)electrode demonstrates a splendid specific capacitance of 1.25 F cm^(−2)at 1 mA cm^(−2)in 1 M Na_(2)SO_(4).This is significantly higher as compared to the capacitance of 0.48 F cm^(−2).Flexible solid-state asymmetric su-percapacitor Ti-FeO-CNT//MnO_(2)is verified with operating voltage of 2.0 V and stability over 3000 cycles,and delivers a high energy density of 2.14 mWh cm^(−3)at power density of 25 mW cm−*** flame synthesis is expected to be widely applicable for the preparation of high-valence metal ions doped nanosized Fe_(2)O_(3)functionalized materials,thus opening up new avenues for energy and catalysis research.

关键词： Ultrasmall Fe_(2)O_(3)nanoparticles Doping Flame synthesis Flexible supercapacitor DFT calculations

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Accuracy Analysis and Design of A3 Parallel Spindle Head

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Chinese Journal of Mechanical Engineering 2016年第2期29卷 239-249页

作者： NI Yanbing zhang Biao SUN Yupeng zhang yuan School of Mechanical Engineering Tianjin University Tianjin 300072 China China Faw Group Corporation R&D Center Changchun 130000 China

As functional components of machine tools, parallel mechanisms are widely used in high efficiency machining of aviation components, and accuracy is one of the critical technical indexes. Lots of researchers have focused on the accuracy problem of parallel mechanisms, but in terms of controlling the errors and improving the accuracy in the stage of design and manufacturing, further efforts are required. Aiming at the accuracy design of a 3-DOF parallel spindle head（A3 head）, its error model, sensitivity analysis and tolerance allocation are investigated. Based on the inverse kinematic analysis, the error model of A3 head is established by using the first-order perturbation theory and vector chain method. According to the mapping property of motion and constraint Jacobian matrix, the compensatable and uncompensatable error sources which affect the accuracy in the end-effector are separated. Furthermore, sensitivity analysis is performed on the uncompensatable error sources. The sensitivity probabilistic model is established and the global sensitivity index is proposed to analyze the influence of the uncompensatable error sources on the accuracy in the end-effector of the mechanism. The results show that orientation error sources have bigger effect on the accuracy in the end-effector. Based upon the sensitivity analysis results, the tolerance design is converted into the issue of nonlinearly constrained optimization with the manufacturing cost minimum being the optimization objective. By utilizing the genetic algorithm, the allocation of the tolerances on each component is finally determined. According to the tolerance allocation results, the tolerance ranges of ten kinds of geometric error sources are obtained. These research achievements can provide fundamental guidelines for component manufacturing and assembly of this kind of parallel mechanisms.

关键词： A3 head error model sensitivity analysis tolerance allocation

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