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Centered Waves for the Two-dimensional Pseudo-Steady van der Waals Gas Satisfied Maxwell's Law Around a Sharp Corner

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Chinese Annals of Mathematics,Series b 2024年第04期45卷 537-554页

作者： Shuangrong li Wancheng SHENG Department of Mathematics Shanghai University Shanghai 200444 China Department of Mathematics Zhejiang University of Science and Technology Department of Mathematics Newtouch Center for Mathematics of Shanghai University Shanghai University

In this paper, the authors study the centered waves for the two-dimensional(2D for short) pseudo-steady supersonic flow with van der Waals gas satisfied Maxwell's law around a sharp corner. In view of the initial value of the specific volume and the properties of van der Waals gas, the centered waves at the sharp corner are constructed by classification. It is shown that the supersonic incoming flow turns the sharp corner by a centered simple wave or a centered simple wave with right-contact discontinuity or a composite wave(jump-fan, fan-jump or fan-jump-fan), or a combination of waves and constant state. Moreover, the critical angle of the sharp corner corresponding to the appearance of the vacuum phenomenon is obtained.

关键词： Centered simple wave Composite wave Two-dimensional Euler equations Van der Waals gas

(DarkAI)Mapping the large-scale density field of dark matter using artificial intelligence

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 143-159页

作者： Zitong Wang Feng Shi Xiaohu Yang Qingyang li Yanming liu Xiaoping li School of Aerospace Science and Technology Xidian UniversityXi’an 710126China Department of Astronomy School of Physics and Astronomyand Shanghai Key Laboratory for Particle Physics and CosmologyShanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute and Key Laboratory for Particle Physics Astrophysics and CosmologyMinistry of EducationShanghai Jiao Tong UniversityShanghai 200240China Institute for Astronomy University of EdinburghRoyal ObservatoryEdinburgh EH93HJUnited Kingdom

Herein,we present a deep-learning technique for reconstructing the dark-matter density field from the redshift-space distribution of dark-matter *** built a UNet-architecture neural network and trained it using the COmoving Lagrangian Acceleration fast simulation,which is an approximation of the N-body simulation with 5123 particles in a box size of 500 h^(-1)***,we tested the resulting UNet model not only with training-like test samples but also with standard N-body simulations,such as the Jiutian simulation with 61443particles in a box size of 1000 h^(-1)Mpc and the ELUCID simulation,which has a different *** real-space dark-matter density fields in the three simulations can be reconstructed reliably with only a small reduction of the cross-correlation power spectrum at 1%and 10%levels at k=0.1 and 0.3 h Mpc-1,*** reconstruction clearly helps to correct for redshift-space distortions and is unaffected by the different cosmologies between the training(Planck2018)and test samples(WMAP5).Furthermore,we tested the application of the UNet-reconstructed density field to obtain the velocity&tidal field and found that this approach provides better results compared with the traditional approach based on the linear bias model,showing a 12.2%improvement in the correlation slope and a 21.1%reduction in the scatter between the predicted and true ***,our method is highly efficient and has excellent extrapolation reliab.lity beyond the training *** provides an ideal solution for determining the three-dimensional underlying density field from the plentiful galaxy survey data.

关键词： dark matter large-scale structure cosmology

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Research on the Control Strategy of Micro Wind-Hydrogen Coupled System based on Wind Power Prediction and Hydrogen Storage System Charging/Discharging Regulation

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Energy Engineering 2024年第6期121卷 1607-1636页

作者： Yuanjun Dai Haonan li baohua li College of Machine Shanghai DianJi UniversityShanghai201306China

This paper addresses the micro wind-hydrogen coupled system,aiming to improve the power tracking capab.lity of micro wind farms,the regulation capab.lity of hydrogen storage systems,and to mitigate the volatility of wind power generation.A predictive control strategy for the micro wind-hydrogen coupled system is proposed based on the ultra-short-term wind power prediction,the hydrogen storage state division interval,and the daily scheduled output of wind power *** control strategy maximizes the power tracking capab.lity,the regulation capab.lity of the hydrogen storage system,and the fluctuation of the joint output of the wind-hydrogen coupled system as the objective functions,and adaptively optimizes the control coefficients of the hydrogen storage interval and the output parameters of the system by the combined sigmoid function and particle swarm algorithm(sigmoid-PSO).Compared with the real-time control strategy,the proposed predictive control strategy can significantly improve the output tracking capab.lity of the wind-hydrogen coupling system,minimize the gap between the actual output and the predicted output,significantly enhance the regulation capab.lity of the hydrogen storage system,and mitigate the power output fluctuation of the wind-hydrogen integrated system,which has a broad practical application prospect.

关键词： Micro wind-hydrogen coupling system ultra-short-term wind power prediction sigmoid-PSO algorithm adaptive roll optimization predictive control strategy

In situ plasmonic & electrochemical fiber-optic sensor for multi-metal-ions detection

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Science China(Information Sciences) 2024年第1期67卷 292-302页

作者： Xiaoling PENG Zhiyong YANG bo PENG Zhi li Zhicong REN Xicheng WANG Jiahai li Zhencheng li liang CHEN Daotong YOU Kaiwei li Jianqing li Tuan GUO Institute of Photonics Technology Jinan University School of Computer Science and Engineering Macau University of Science and Technology Institute for Environmental and Climate Research Jinan University Key Laboratory of bionic Engineering of Ministry of Education Jilin University

High precision and high throughput detection of heavy metal ions is essential for water quality monitoring and ***,we propose a plasmonic & electrochemical dual-mode fiber sensing probe for label-free and real-time detection of multiple ions(Pb2+and Cu2+as examples).This sensor comprises a multimode fiber-single mode fiber reflection probe,the outer surface of which is coated with a gold nanofilm to excite the surface plasmon resonance(SPR) optically and simultaneously serves as an electrochemical working *** traditional electrochemical detection,the enrichment of ions cannot be detected in ***,by utilizing the plasmonic & electrochemical dual-mode detection method,various kinds of metal ions can be deposited onto the gold nanofilm and selectively oxidized during forward potential scanning,and the entire electrochemical process can be monitored by SPR *** experimentally demonstrate that the sensor can simultaneously detect Pb2+and Cu2+in a mixed solution in real-time,providing a linear response over the ion concentration range from 10-12to 10-7M and offering an excellent detection limit(1.69×10-14–5.49×10-13M).The proposed dual-mode fiber sensor has the benefits of remote sensing,compact footprint,and cost-effectiveness and shows excellent potential for water quality risk management in difficult-to-reach environments.

关键词： optical fiber sensor surface plasmon resonance electrochemical measurement ions detection water pollution

The adsorption effect of aquaculture residual feed on heavy metals and its impact on microbial metab.lism of feed

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Ecological Processes 2024年第2期13卷 246-259页

作者： Sufeng Wang Zijng Wang Wen Zhang Jingshan li Mingyang lin li Chen State Key Laboratory of Metastable Materials Science and Technology Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse Yanshan University Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province College of Biology and Environmental EngineeringZhejiang Shuren University Hebei Ocean & Fisheries Science Research Institute

background Intensive and large-scale aquaculture has a high biological density, and a large amount of artificial feed must be provided. As a result, residual feed would be discharged into natural water bodies with water exchange. Due to heavy metal pollution in surface water, residual feed may adsorb heavy metals in the water, affecting the subsequent microbial degradation of feed and the restoration of the water environment. The combined ecological impacts of these two types of pollution urgently need to be *** This study explored the adsorption effect of residual feed on heavy metals and its impact on microbial degradation of residual feed. The results showed that both the insoluble component（mainly fiber, ash, and ether extract, abbreviated as FAE） and soluble component（soluble protein and starch） of the feed had adsorption effects on heavy metals. As the salinity increased, the adsorption capacity of Cu2+and Cd2+decreased, while the adsorption effect on Pb2+was not changed significantly. The adsorption of heavy metals by residual feed could affect the biological degradation of residual feed. The residual feed could adsorb heavy metals and bacterial cells simultaneously, forming FAE-b（bacteria）-S（starch）-Pr（protein）-metal adsorption complex. This adsorption effect could reduce the negative impact of heavy metals on microbial degradation of residual feed. The simulated degradation experiments in actual water bodies also confirmed this. However, the accumulation of heavy metals in residual feed may bring negative effects, such as being consumed by aquatic organisms and entering the food *** The results of this study provide a basis for the collection and centralized treatment of residual feed in aquaculture, as well as the control and remediation of residual feed pollution in natural water bodies.

关键词： Residual feed Adsorption complex Feed pollution Heavy metal

Dimensional reduction enhances photocatalytic carbon dioxide reduction performance of metal-organic frameworks

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Nano Research 2024年第5期17卷 3653-3659页

作者： Kaiyue Ma Jixin li Jinlu liu Chunguang li Zhan Shi Shouhua Feng State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China

Metal-organic frameworks(MOFs)have shown significant potential as *** has been widely assumed that all catalytic active sites within MOFs are functional in photocatalytic reactions but for a three-dimensional MOF,whether the internal catalytic active sites can effectively absorb.light and actively contribute to photocatalytic reactions remains to be *** this context,we synthesized a two-dimensional nanosheet MOF(2D-MOF)and a three-dimensional bulk MOF(3D-MOF)composed of Zr^(6) clusters and tetracarboxylic porphyrin(TCPP)by the approach described in the ***(bpy)(CO)^(3)Cl(bpy=2,2’-bipyridine),which has remarkable CO_(2) photoreduction ab.lity,was introduced to the two MOFs to create two new photocatalysts 2D-MOF-Re and 3D-MOF-Re,*** CO_(2) reduction experiments show that based on the equal number of catalytic active sites,the CO turnover number(TON)of 2D-MOF-Re reaches 27.8 in 6 h,which is 50 times that of *** result shows that certain catalytic active sites inside the bulk MOF are inactive due to the inab.lity to absorb *** study illuminates the potential of the dimensional reduction approach in the design of photocatalysts to exploit the capab.lities fully.

关键词： photocatalysis CO_(2)reduction metal-organic frameworks(MOFs) nanosheets light absorption

Single-atom Zn confined in hierarchical hollow microstructure as an acid/base-resistant microwave absorption materials

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Nano Research 2024年第8期17卷 6785-6794页

作者： Yue Lou Jiao li Xiaokun li Zhenyu Zhu Zhan Shi biao Xu School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China

Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme ***,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis *** large specific surface area(SbET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the ***,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host *** porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature *** the same time,they can also be used in various complex environments,such as acidic and basic ***,NC-1000,with high surface area,low density,and good chemical stab.lity,obtained a minimum reflection loss(RLmin)of−50.5 db and an effective absorption bandwidth(EAb)exceeding 5.1 GHz at the thickness of 1.9 *** soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased byble raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.

关键词： hierarchical hollow microstructure microwave absorption metal-organic framework(MOF) impedance matching singleatom Zn acid/base-resistant

Synergistically enhanced dielectric, insulating and thermally conductive performances of sandwich PMMA based dielectric films

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Progress in Natural Science:Materials International 2024年第3期34卷 591-597页

作者： Dongmei Zhang Yufan li Yuchao li Zhonggui Sun Hanxue Zhu Lujia Yang Yanhu Zhan Yankai li Shi Wang Jun-Wei Zha School of Mathematical Sciences Liaocheng University School of Materials Science and Engineering Liaocheng University State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications School of Chemistry and biological Engineering University of Science and Technology Beijing

A tri-layered(b-G-b) dielectric films were simply prepared by alternatively spin-coating boron nitride/polymethylmethacrylate(bN/PMMA, b) and graphene nanosheets(GNS/PMMA, G) compound solutions. The structure, morphology, thermal conductivity, and particularly the dielectric and relaxation behaviors were systematically studied. Results showed that a good exfoliation and dispersion of bN and GNS can be simply achieved through intensive mechanical compounding with PMMA in the internal mixer. The dielectric constant and breakdown strength of the obtained 1-3-1(b-G-b) sandwich composite film reached 4.3(@1 kHz) and 458.6kV/mm, being 119 % and 113 % higher than that of pure PMMA, respectively. Furthermore, the overall thermal conductivity of sandwich 1-3-1 composite increased by 112 % due to the addition of thermally conductive bN and GNS. The sandwich design strategy provided an effective way of achieving good permittivity, high insulation, and improved thermal conductivity simultaneously, showing potential applications in the miniaturization and integration of electronic devices.

关键词： breakdown strength Composites Dielectric constant Sandwich structure Thermal conductivity

Design and fabrication of Nd-Fe-b magnet with excellent thermal stab.lity

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Journal of Rare Earths 2024年第5期42卷 980-986,I0006页

作者： Rui Han Shengzhi Dong Dong li Dongmin Zhang Hongsheng Chen Jiyuan Xu George CHadjipanayis Zhuolin li Ying Zhang Wei li Division of Functional Materials Research Central Iron and Steel Research InstituteBeijing100081China Department of Physics and Astronomy Sharp Lab University of DelawareNewarkDE19716USA beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing100190China

A novel Nd-Fe-b type permanent magnet with excellent thermal stab.lity was designed by Co replacing Fe in the main phase and the grain boundary *** remanence and coercivity temperature coefficient reach 0.058%/℃and 0.465%/℃in the te mperature range from 25 to 100℃,which are much lower than those of commercial Nd-Fe-b *** enhanced Curie temperature is obtained for the novel magnet due to the Co substitution,which significantly improves the operating *** microstructure result reveals that an amorphous phase exists in the intergranular grains which is probably responsible for the deterioration of intrinsic *** work can provide a reference for the design and optimization of components of sintered Nd-Fe-b magnets with excellent thermal stab.lity.

关键词： Thermal stab.lity Remanence temperature coefficient Operating temperature Atomic substitution Rare earths

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