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A positive trend in the stability of global offshore wind energy

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Acta Oceanologica Sinica 2024年第1期43卷 123-134页

作者： Chongwei zheng Dalian Naval Academy Dalian 116018China marine Resources and Environment Research Group on the maritime Silk Road Dalian 116018China Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China

The recognition on the trend of wind energy stability is still extremely rare,although it is closely related to acquisition efficiency,grid connection,equipment lifetime,and costs of wind energy *** the 40-year(1979–2018)ERA-Interim data from the European Center for medium-Range Weather Forecasts,this study presented the spatial-temporal distribution and climatic trend of the stability of global offshore wind energy as well as the abrupt phenomenon of wind energy stability in key regions over the past 40 years with the climatic analysis method and mann-Kendall(m-K)*** results show the following 5 points.(1)According to the coefficient of variation(C_(v))of the wind power density,there are six permanent stable zones of global offshore wind energy:the southeast and northeast trade wind zones in the Indian,Pacific and Atlantic oceans,the Southern Hemisphere westerly,and a semi-permanent stable zone(North Indian Ocean).(2)There are six lowvalue zones for both seasonal variability index(S_(v))and monthly variability index(m_(v))globally,with a similar spatial distribution as that of the six permanent stable zones.m_(v) and S_(v) in the Arabian Sea are the highest in the world.(3)After C_(v),m_(v) and S_(v) are comprehensively considered,the six permanent stable zones have an obvious advantage in the stability of wind energy over other sea areas,with C_(v) below 0.8,m_(v) within 1.0,and S_(v) within 0.7 all the year round.(4)The global stability of offshore wind energy shows a positive climatic trend for the past four decades.C_(v),m_(v) and S_(v) have not changed significantly or decreased in most of the global ocean during 1979 *** is,wind energy is flat or more stable,while the monthly and seasonal variabilities tend to shrink/smooth,which is beneficial for wind energy utilization.(5)C_(v) in the low-latitude Pacific and m_(v) and S_(v) in both the North Indian Ocean and the low-latitude Pacific have an obvious abrupt phenomenon at the end of

关键词： global oceans wind energy stability spatial-temporal distribution climatic trend

microscale spherical TiO_(2)powder prepared by hydrolysis of TiCl_(4)solution:Synthesis and kinetics

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Particuology 2024年第1期84卷 60-71页

作者： Peiyi Yan Ying Zhang Shili zheng School of Rare Earths University of Science and Technology of ChinaHefei230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341119China Key Laboratory of Green Process and Engineering National Engineering Research Center of Green Recycling for Strategic Metal ResourcesInstitute of Process EngineeringChinese Academy of SciencesBeijing100190China State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization Panzhihua617000China

Hydrolysis of TiCl_(4)solution is capable of preparing microscale TiO_(2)*** research studied the synthesis of microscale spherical TiO_(2)powders and the hydrolysis *** effects of the flow field generated by different agitators and baffles in the crystallizer,the initial free acid concentration,the initial equivalent TiO_(2)concentration,and the temperature on the hydrolysis progress and powder morphology were systematically *** results show that the flow field in a crystallizer can significantly affect the morphology and particle size of the powders,and the axial flow can improve the sphericity of the *** increased free HCl and equivalent TiO_(2)concentrations in the pregnant solution inhibit the forward hydrolysis reaction,prolong the time to reach equilibrium,and reduce the *** appropriate temperature matching the compositions of the pregnant solution is crucial for the powder morphology and *** with sizes ranging from around 5 um-40μm can be tuned under controlled flow field,solution compositions,and temperature *** addition,the Cheng and Wunderlich modified Avrami equation was used for the crystallization kinetic *** effects of the free HCl concentration,equivalent TiO_(2)concentration,and hydrolysis temperature are reflected in the reaction rate constant and active nuclei reduction *** the free HCl and equivalent TiO_(2)concentrations will reduce the reaction rate constant and accelerate the deactivation of the active nuclei,thus increasing the final powder size,while increasing the temperature will lead to the opposite results.

关键词： TiCl_(4) Hydrolysis microscale TiO_(2) Spherical Kinetics

Improving the spaceborne GNSS-R altimetric precision based on the novel multilayer feedforward neural network weighted joint prediction model

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Defence Technology（防务技术） 2024年第2期32卷 271-284页

作者： Yiwen Zhang Wei zheng Zongqiang Liu Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China China Academy of Aerospace Science and Innovation Beijing 100176China State Key Laboratory of Space-Ground Integrated Information Technology Beijing Institute of Satellite Information EngineeringBeijing 100194China

Global navigation satellite system-reflection(GNSS-R)sea surface altimetry based on satellite constellation platforms has become a new research direction and inevitable trend,which can meet the altimetric precision at the global scale required for underwater *** present,there are still research gaps for GNSS-R altimetry under this mode,and its altimetric capability cannot be specifically ***,GNSS-R satellite constellations that meet the global altimetry needs to be ***,the matching precision prediction model needs to be established to quantitatively predict the GNSS-R constellation altimetric ***,the GNSS-R constellations altimetric precision under different configuration parameters is calculated,and the mechanism of the influence of orbital altitude,orbital inclination,number of satellites and simulation period on the precision is analyzed,and a new multilayer feedforward neural network weighted joint prediction model is ***,the fit of the prediction model is verified and the performance capability of the model is tested by calculating the R2 value of the model as 0.9972 and the root mean square error(RmSE)as 0.0022,which indicates that the prediction capability of the model is ***,using the novel multilayer feedforward neural network weighted joint prediction model,and considering the research results and realistic costs,it is proposed that when the constellation is set to an orbital altitude of 500 km,orbital inclination of 75and the number of satellites is 6,the altimetry precision can reach 0.0732 m within one year simulation period,which can meet the requirements of underwater navigation precision,and thus can provide a reference basis for subsequent research on spaceborne GNSS-R sea surface altimetry.

关键词： GNSS-R satellite constellations Sea surface altimetric precision Underwater navigation multilayer feedforward neural network

Black hole evaporation and its remnants with the generalized uncertainty principle including a linear term

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Communications in Theoretical Physics 2024年第2期76卷 125-136页

作者： Bo Yu zheng-wen Long College of Physics Guizhou UniversityGuiyang550025China

In recent years,researchers have investigated the evaporation of Schwarzschild black holes using various forms of the generalized uncertainty principle(GUP),metric quantum correction,and noncommutative geometry,***,there are differences between the GUP correction and the other two methods in terms of describing the later stages of black hole ***,some studies argue that the GUP with a negative parameter cannot effectively correct black hole evaporation,while others contend that the positivity or negativity of the GUP parameters should not affect the correction *** the above into consideration,we reconsider black hole evaporation with the generalized uncertainty principle including a linear term(LGUP),and examine the case of negative *** results indicate that the evaporation behavior of both Schwarzschild black holes and Reissner–Nordstr?m black holes,under LGUP correction,is consistent with the results of metric quantum correction and non-commutative ***,the negative parameter LGUP can also effectively correct for black hole evaporation.

关键词： black hole evaporation generalized uncertainty principle negative parameter

Greedy Lattice Paths with General Weights

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Acta mathematica Sinica,English Series 2024年第9期40卷 2213-2222页

作者： Yin Shan CHAng An Qi zheng College of mathematics Sichuan UniversityChengdu 610065P.R.China

Let{X_(v):v∈Z^(d)}be *** *** S(π)=Σ_(v∈π)X_(v)be the weight of a self-avoiding lattice pathπ.Let m_(n)=max{S(π):πhas length n and starts from the origin}.We are interested in the asymptotics of mn as n→∞.This model is closely related to the first passage percolation when the weights{X_(v):v∈Z^(d)}are non-positive and it is closely related to the last passage percolation when the weights{X_(v):v∈Z^(d)}are *** general weights,this model could be viewed as an interpolation between first passage models and last passage ***,this model is also closely related to a variant of the position of right-most particles of branching random *** the two assumptions that∃α>0,E(X_(0)^(+))^(d)(log^(+)X_(0)^(+))^(d+α)mber m such that mn/n converges to a deterministic constant m in L^(1)as n tends to *** under the stronger assumptions that∃α>0,E(X_(0)^(+))^(d)(log^(+)X_(0)^(+))^(d+α)m_(n)/n converges to the same constant m almost surely as n tends to infinity.

关键词： Last passage percolation first passage percolation greedy lattice path

Transfer film effects induced by 3D-printed polyether-ether-ketone with excellent tribological properties for joint prosthesis

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Bio-Design and manufacturing 2024年第1期7卷 43-56页

作者： Yang Li Jibao zheng Changning Sun Dichen Li State Key Laboratory for manufacturing System Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710054China National medical Products Administration(NmPA)Key Laboratory for Research and Evaluation of Additive manufacturing medical Devices Xi’an Jiaotong UniversityXi’an 710054China

Based on the building principle of additive manufacturing,printing orientation mainly determines the tribological properties of joint *** this study,we created a polyether-ether-ketone(PEEK)joint prosthesis using fused filament fabrication and investigated the effects of printing orientation on its tribological properties using a pin-on-plate tribometer in 25% newborn calf *** ultrahigh molecular weight polyethylene transfer film is formed on the surface of PEEK due to the mechanical capture of wear debris by the 3D-printed groove morphology,which is significantly impacted by the printing orientation of *** the printing orientation was parallel to the sliding direction of friction,the number and size of the transfer film increased due to higher steady *** transfer film protected the matrix and reduced the friction coefficient and wear rate of friction pairs by 39.13%and 74.33%,***,our findings provide a novel perspective regarding the role of printing orientation in designing knee prostheses,facilitating its practical applications.

关键词： 3D printing orientation Transfer film Tribological properties Polyether-ether-ketone Knee prosthesis

Optical Extinctions of Inter-Arm molecular Clouds in m31:A Pilot Study for the Upcom.ng CSST Observations

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Research in Astronomy and Astrophysics 2024年第6期24卷 323-333页

作者： Cailing Chen zheng zheng Chao-Wei Tsai Sihan Jiao Jing Tang Jingwen Wu Di Li Yun zheng Linjing Feng Yujiao Yang Yuan Liang National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Radio Astronomy and Technology Chinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Zhejiang Lab Hangzhou 311121China

Recent submillimeter dust thermal emission observations have unveiled a significant number of inter-arm massive molecular clouds in ***,the effectiveness of this technique is limited to its sensitivity,making it challenging to study more distant *** study introduces an alternative approach,utilizing optical extinctions derived from space-based telescopes,with a focus on the forthcom.ng China Space Station Telescope(CSST).We first demonstrate the capability of this method by constructing dust extinction maps for 17 inter-arm massive molecular clouds in m31 using the Panchromatic Hubble Andromeda Treasury *** analysis reveals that inter-arm massive molecular clouds with an optical extinction(A_(V)) greater than 1.6 mag exhibit a notable A_(V) excess,facilitating their *** majority of these inter-arm massive molecular clouds show an A_(V) around 1 mag,aligning with measurements from our JCmT *** validation using a mock CSST RGB star catalog confirms the method's *** show that the derived A_(V)values using CSST z and y photometries align more closely with the input *** clouds with A_(V)> 1.6 mag can also be identified using the CSST mock *** thus claim that future CSST observation clouds provide an effective way for the detection of inter-arm massive molecular clouds with significant optical extinction in nearby galaxies.

关键词： infrared:stars ISm:clouds Galaxy:structure

High-entropy catalysts for electrochemical water-electrolysis of hydrogen evolution and oxygen evolution reactions

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Frontiers in Energy 2024年第3期18卷 265-290页

作者： Simiao SHA Riyue GE Ying LI Julie m.CAIRNEY Rongkun zheng Sean LI Bin LIU Jiujun ZHAng Wenxian LI School of materials Science and Engineering Shanghai UniversityShanghai 200444China School of Chemical and Environmental Engineering Anhui Polytechnic UniversityWuhu 241000China Australian Centre for microscopy and microanalysis School of AerospaceMechanical and Mechatronic EngineeringThe University of SydneySydney NSW 2006Australia School of Physics The University of SydneySydney NSW 2006Australia School of materials Science and Engineering UNSW Materials&Manufacturing Futures InstituteUniversity of New South WalesSydney NSW 2052Australia College of materials Science and Engineering Fuzhou UniversityFuzhou 350108China

High entropy materials (HEms) have developed rapidly in the field of electrocatalytic water-electrolysis for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) due to their unique properties. In particular, HEm catalysts are composed of many elements. Therefore, they have rich active sites and enhanced entropy stability relative to single atoms. In this paper, the preparation strategies and applications of HEm catalysts in electrochemical water-electrolysis are reviewed to explore the stabilization of HEms and their catalytic mechanisms as well as their application in support green hydrogen production. First, the concept and four characteristics of HEms are introduced based on entropy and composition. Then, synthetic strategies of HEm catalysts are systematically reviewed in terms of the categories of bottom-up and top-down. The application of HEms as catalysts for electrochemical water-electrolysis in recent years is emphatically discussed, and the mechanisms of improving the performance of electrocatalysis is expounded by combining theoretical calculation technology and ex-situ/in situ characterization experiments. Finally, the application prospect of HEms is proposed to conquer the challenges in HEm catalyst fabrications and applications.

关键词： high-entropy electrocatalysis synthetic methods water-electrolysis hydrogen and oxygen evolutions

Spatiotemporal Prediction of Urban Traffics Based on Deep GNN

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Computers, materials & Continua 2024年第1期78卷 265-282页

作者： m.ng Luo Huili Dou Ning zheng School of Computer Science Hangzhou Dianzi UniversityHangzhou310018China Zhejiang Institute of Communications Hangzhou310012China School of Cyberspace Security Hangzhou Dianzi UniversityHangzhou310018China

Traffic prediction already plays a significant role in applications like traffic planning and urban management,but it is still difficult to capture the highly non-linear and complicated spatiotemporal correlations of traffic *** well as to fulfil both long-termand short-termprediction objectives,a better representation of the temporal dependency and global spatial correlation of traffic data is *** order to do this,the Spatiotemporal Graph Neural Network(S-GNN)is proposed in this research as amethod for traffic *** S-GNN simultaneously accepts various traffic data as inputs and investigates the non-linear correlations between the *** terms of modelling,the road network is initially represented as a spatiotemporal directed graph,with the features of the samples at the time step being captured by a convolution *** order to assign varying attention weights to various adjacent area nodes of the target node,the adjacent areas information of nodes in the road network is then aggregated using a graph *** data is output using a fully connected layer at the *** findings show that S-GNN can improve short-and long-term traffic prediction accuracy to a greater extent;in comparison to the control model,the RmSE of S-GNN is reduced by about 0.571 to 9.288 and the mAE(mean Absolute Error)by about 0.314 to *** experimental results on two real datasets,Pe mSD7(m)and PEmS-BAY,also support this claim.

关键词： Urban traffic traffic temporal correlation GNN prediction