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Boosting the Activity and Stability of the Photoreduction of diluted CO_(2) by Copper Oxide Decorated CeO_(2) Hetero-shells

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Chemical Research in Chinese Universities 2024年第3期40卷 513-520页

作者： XIAO Mingjiao LI di WEI Yanze HE Yilei WAnG Zumin YU Ranbo Department of Physical Chemistry School of Metallurgical and Ecological EngineeringUniversity of Science&Technology BejingBeijing 100083P.R.China State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190P.R.China Key Laboratory of Biopharmaceutical Preparation and Delivery Chinese Academy of SciencesBeijing 100190P.R.China

Inspired by the natural photosynthesis systems,the integrated harnessing and conversion of CO_(2) present a promising solution for addressing the ever-rising global atmospheric concentration of CO_(2).Hollow multi-shelled structured(HoMS)photocatalysts,featuring alternating shells and cavities,have recently gained recognition as efficient nano-reactors for capturing CO_(2) molecules and facilitating effective photoreduction within these hierarchical structures,leveraging the preeminent enrichment *** this work,to augment the photocatalytic efficacy of HoMS in CO_(2) treatment,highly dispersed Cu_(x)O nanoparticles(nPs)were incorporated on the CeO2 shells through a polymer-assisted impregnation method to create more active sites and strengthen the interaction between the hetero-shells and CO_(2) *** photoreduction of the CO_(2)-to-CO rate under a diluted CO_(2)(15%,volume fraction)atmosphere is improved by the introduction of Cu_(x)O nPs,with the highest CO yielding rate reaching 120µmol·h^(−1)·g^(−1) without any sacrificial *** comparison experiments and theoretical calculations reveal that the Cu_(x)O nPs promote the adsorption of CO_(2) molecules in HoMS,accelerate the charge transfer efficiency,and stabilize the surface oxygen vacancies(Ovs)during the photoreduction CO_(2) conversion *** hope these easy-to-prepare HoMS nanoreactors can contribute to the effective enrichment and valorization of CO_(2) in industrial exhaust gases.

关键词： Photoreduction CO_(2) Cu_(x)O/CeO_(2)hollow multi-shell structure(HoMS) Hetero-shell

Spatiotemporal changes in sunshine duration and its influential factors in Chongqing,China from 1961 to 2020

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Journal of Mountain Science 2024年第6期21卷 2005-2024页

作者： LI Jun XIA Hongxuan JIAnG Jinge XU Weifeng WEn di XU Junfeng College of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Key Laboratory of GIS Application of Chongqing Chongqing 401331China Chongqing Key Laboratory of Earth Surface Processes and Environmental Remote Sensing in Three Gorges Reservoir area Chongqing 401331China Institute of Remote Sensing and Earth Sciences School of Institute of Remote Sensing and Earth SciencesSchool of ScienceHangzhou Normal UniversityHangzhou 311121China

The surface solar radiation in most parts of the world has undergone a phenomenon known as global dimming and brightening,characterized by an initial decrease followed by an *** a result,the sunshine duration(SD)has decreased in the past 60 *** the backdrop of global dimming and brightening,SD has decreased to varying degrees in many regions of *** the observed data of SD,cloud amount(total cloud amount and low cloud amount,abbreviated as TCA and LCA),precipitation,and relative humidity(RH)from 34 meteorological stations in Chongqing during the period of 1961-2020,along with a digital elevation model(DEM)with a resolution of 90 m,this study analyzed the spatiotemporal variations and influencing factors of *** analysis employed methods such as linear regression,Mann-Kendall test,wavelet transformation,and DEM-based possible SD distributed *** results showed that the annual SD in Chongqing has significantly decreased over the last 60 years,with a decreasing interannual trend rate(ITR)of 40.4 h/*** for no obvious trend in spring,SD decreased significantly in summer,autumn and winter at the ITR of 21.1 h/10a,8.5 h/10a and 7.5 h/10a,*** abrupt decrease in the annual SD was found in *** difference before and after the abrupt decrease was 177.7 *** difference before and after the abrupt decrease was 177.7 *** annual SD possessed the oscillation period of *** spatial heterogeneity of the mean annual SD during the last 60 years was *** distribution of SD in Chongqing is high in the northeast and low in the *** addition,about 73%of the total area in Chongqing showed a significant and very significant decreasing *** regions with significant changes are mainly concentrated in the regions with altitudes of 200~1000 *** increasing LCA was the main cause of the decrease of the annual SD in the regions with 200-400 m altitude decreased the most and changed the *** LCA is the prim

关键词： Sunshine duration Spatiotemporal changes Mann-Kendall test Wavelet analysis Geodetector model

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In-situ additive manufacturing of high strength yet ductility titanium composites with gradient layered structure using n_(2)

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International Journal of Extreme Manufacturing 2024年第3期6卷 387-409页

作者： Yunmian Xiao Changhui Song Zibin Liu Linqing Liu Hanxiang Zhou di Wang Yongqiang Yang School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510641People’s Republic of China

It has always been challenging work to reconcile the contradiction between the strength and plasticity of titanium *** powder bed fusion(LPBF) is a convenient method to fabricate innovative composites including those inspired by gradient layered *** this work,we used LPBF to selectively prepare Ti n/Ti gradient layered structure(GLSTi)composites by using different n_(2)–Ar ratios during the LPBF *** systematically investigated the mechanisms of in-situ synthesis Ti n,high strength and ductility of GLSTi composites using microscopic analysis,TEM characterization,and tensile testing with digital image ***,a digital correspondence was established between the n_(2) concentration and the volume fraction of LPBF in-situ synthesized Ti *** results show that the GLSTi composites exhibit superior mechanical properties compared to pure titanium fabricated by LPBF under pure ***,the tensile strength of GLSTi was more than 1.5times higher than that of LPBF-formed pure titanium,reaching up to 1100 MPa,while maintaining a high elongation at fracture of 17%.GLSTi breaks the bottleneck of high strength but low ductility exhibited by conventional nanoceramic particle-strengthened titanium matrix composites,and the hetero-deformation induced strengthening effect formed by the Ti n/Ti layered structure explained its strength-plasticity balanced *** microhardness exhibits a jagged variation of the relatively low hardness of 245 HV0.2 for the pure titanium layer and a high hardness of 408 HV0.2 for the n_(2) in-situ synthesis *** study provides a new concept for the structure-performance digital customization of 3D-printed Ti-based composites.

关键词： laser powder bed fusion layered structure composites in-situ synthesis Tin strength-plasticity synergy

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Joint Transmit and Reflective Beamforming Design for Active IRS-Aided SWIPT Systems

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Chinese Journal of Electronics 2024年第2期33卷 536-548页

作者： Weiping SHI Qingqing WU di WU Feng SHU Jiangzhou WAnG School of Electronic and Optical Engineering Nanjing University of Science and Technology Department of Electronic Engineering Shanghai Jiao Tong University School of Information and Communication Engineering Hainan University Department of Automation Shanghai Jiao Tong University School of Engineering University of Kent

To further improve the performance of passive intelligent reflecting surface(IRS)-assisted communication systems and mitigate the serious path loss due to “double-fading ” of IRS-assisted links, an active IRS-aided simultaneous wireless information and power transfer(SWIPT) system is investigated. This paper jointly optimizes the transmit beamforming at the base station(BS) and the phase shifts at the active IRS in order to maximize the power collected by the energy harvesting receiver under both perfect and imperfect channel state information(CSI)states, subject to the signal-to-interference-noise ratio constraint of the information decoding receiver, and the power constraints of the BS/IRS. Under perfect CSI, the alternating optimization algorithm is utilized for obtaining the transmit beamforming at the BS and the phase shifts at the active IRS. For each subproblem, we first transform nonconvex objective function and constraints into convex ones by performing a first-order Taylor expansion. Then, each subproblem is solved by using the interior point method. Given that obtaining perfect CSI is impractical, two robust beamforming designs are proposed for imperfect CSI case. Under the bounded CSI error model, we first transform the non-convex optimization problem into two semidefinite programming subproblems, and then solve each subproblem based on S-procedure and sequential rank-one constraint relaxation(SROCR) techniques. Under the stochastic CSI error model, the alternating optimization method is applied in an iterative manner based on Bernstein-type inequality and SROCR technique. Simulation results show that both robust and non-robust schemes for active IRS-assisted SWIPT systems can achieve extremely superior performance over conventional passive IRS-assisted systems under the same overall power budget.

关键词： Wireless communication Semidefinite programming Array signal processing Simulation Stochastic processes Transforms Receivers

Optical two-dimensional coherent spectroscopy of excitons in transition-metal dichalcogenides

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frontiers of physics 2024年第2期19卷 141-148页

作者： YanZuo Chen ShaoGang Yu Tao Jiang XiaoJun Liu XinBin Cheng di Huang State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsInnovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China MOE Key Laboratory of Advanced Micro-Structured Materials Shanghai Frontiers Science Center of Digital OpticsInstitute of Precision Optical Engineeringand School of Physics Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai 200092China

Exciton physics in atomically thin transition-metal dichalcogenides(TMDCs)holds paramount importance for fundamental physics research and prospective ***,the experimental exploration of exciton physics,including excitonic coherence dynamics,exciton many-body interactions,and their optical properties,faces challenges stemming from factors such as spatial heterogeneity and intricate many-body *** this perspective,we elaborate upon how optical two-dimensional coherent spectroscopy(2DCS)emerges as an effective tool to tackle the challenges,and outline potential directions for gaining deeper insights into exciton physics in forthcoming experiments with the advancements in 2DCS techniques and new materials.

关键词： monolayer transition-metal dichalcogenides two-dimensional coherent spectroscopy

Tiered clustering-based management architecture in mega-satellite networks

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Science China(Information Sciences) 2024年第5期67卷 215-227页

作者： Qi HAO di ZHOU Min SHEnG Yan SHI Jiandong LI State Key Laboratory of Integrated Service networks Xidian University

Hybrid orbital networking and the proliferation of satellites raise explosive management complexity in mega-satellite networks(MSns) and prompt the management architecture to the hierarchy. In this regard, we propose a tiered clustering-based management architecture(TCMA) to realize the high-efficient and low-cost management performance. Specifically, based on the constrained satellite coverage, we derive an expression of the mapping relationship between the required control overhead of the controller interaction,the average path length of the proposed TCMA, and the corresponding number of management tiers and cluster size. The expression can determine the optimal number of tiers of the TCMA by minimizing the required flow table size between controllers, while ensuring high transmission efficiency. We then exhibit the elasticity of the hierarchical TCMA by adding the peer connections at the second-highest management tier to reduce maximum redundant paths. Simulation results verify the effectiveness of the proposed TCMA and illustrate that a 3-tier TCMA is sufficient for thousands of satellites.

关键词： mega-satellite networks hierarchical architecture average hop tiered structure clustering

Predicting microseismic,acoustic emission and electromagnetic radiation data using neural networks

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 616-629页

作者： Yangyang di Enyuan Wang Zhonghui Li Xiaofei Liu Tao Huang Jiajie Yao School of Materials Engineering Changshu Institute of TechnologySuzhou215506China Key Laboratory of Gas and Fire Control for Coal Mines(China University of Mining and Technology) Ministry of EducationXuzhou221116China School of Safety Engineering China University of Mining and TechnologyXuzhou221116China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyXuzhou221116China

Microseism,acoustic emission and electromagnetic radiation(M-A-E)data are usually used for predicting rockburst ***,it is a great challenge to realize the prediction of M-A-E *** this study,with the aid of a deep learning algorithm,a new method for the prediction of M-A-E data is *** this method,an M-A-E data prediction model is built based on a variety of neural networks after analyzing numerous M-A-E data,and then the M-A-E data can be *** predicted results are highly correlated with the real data collected in the *** field verification,the deep learning-based prediction method of M-A-E data provides quantitative prediction data for rockburst monitoring.

关键词： Microseism Acoustic emission Electromagnetic radiation neural networks Deep learning Rockburst

Environmental characteristics of trace metals in seawater from the ninety East Ridge in the Indian Ocean

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Journal of Oceanology and Limnology 2024年第4期42卷 1119-1129页

作者： Jingxi LI di ZHAnG Fenghua JIAnG Hong CHEn Wei CAO Chengjun SUn Key Laboratory of Marine Eco-Environmental Science and Technology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China College of Safety and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China Laoshan Laboratory of Marine Science and Technology Laboratory of Marine Drugs and Biological ProductsQingdao 266071China

The ninety East Ridge in the Indian Ocean has complex and unique *** concentrations and distribution characteristics of 10 trace metals(V,Cr,Mn,Fe,Co,ni,Cu,Cd,Pb,and U)in seawater from the ninety East Ridge in the Indian Ocean were *** show that the average concentrations of different trace metals in all the collected seawater samples were 1.134μg/L for V,0.158μg/L for Cr,0.489μg/L for Mn,0.427μg/L for Fe,0.011μg/L for Co,0.395μg/L for ni,0.403μg/L for Cu,0.097μg/L for Cd,0.139μg/L for Pb,and 3.470μg/L for *** in the horizontal and vertical distributions of all measured trace metals were revealed,and the occurrence of high concentrations was *** addition,the significant differences in the concentration distribution of different trace metals in seawater on both sides of the ninety East Ridge present regional segmentation in the area for various trace metals in deep sea *** study provided basic data for future investigations on the environmental and ecological impact of trace metals in the Indian Ocean and the potential water mass transport mechanism.

关键词： trace metal environmental characteristic ninety East Ridge seawater Indian Ocean

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Investigation of wake-induced vibration interference between two staggered wave-cone cylinders at subcritical Reynolds number

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Journal of Hydrodynamics 2024年第2期36卷 378-393页

作者： Lin Zou di-wei Liu Jian Liu Hong-cheng Zuo Yin-huan Zheng Hao Xia School of Mechanical and Electronic Engineering Wuhan University of TechnologyWuhan430070China Department of Aeronautical and Automotive Engineering Loughborough UniversityLoughboroughUK

The wake induced vibration(WIV)of a one-and two-degree-of-freedom(1DOF,2DOF)downstream wave-cone cylinder(WCC)behind a stationary equal-size upstream wave-cone cylinder in the staggered arrangement is numerically investigated at subcritical Reynolds number of 3900 by using shear stressed transfer(SST)k-ωturbulence *** streamwise pitch ratios(P/Dm)vary from 4 to 6 with a fixed incident angleα=8°.Experimental measurements were also performed for the validation of the present numerical *** is found that the largest vibration amplitude in crossflow direction occurred at P/Dm=4,Ur=8 with small difference of streamwise vibration at P/Dm=4,*** from single wavy-cone cylinder(SWCC),the downstream flexible one of a pair staggered WCCs got larger vibration amplitude during phase switching stage instead of in-phase *** upstream wake will suppress the triple frequency of main frequency in the power spectra density(PSD)functions of Cl but stimulate the double one of *** intriguing vibration mechanism happened in all 2DOF cases where the trajectory of downstream WCC is a significant ellipse rather than a figure of *** transformation of phase switching and the variation of the main frequency of drag coefficient(Cd)can be explained by the vortex-shedding modes of downstream WCC.

关键词： Two wave-cone cylinders staggered arrangement wake induced vibration phase switching vortex shedding