检索结果-南通市图书馆

Plate tectonics in the Archean:Observations versus interpretations

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第1期67卷 1-30页

作者： YongFei zheng School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Key Laboratory of Crust-Mantle Materials and Environment Chinese Academy of SciencesHefei 230026China Center of Excellence for Comparative Planetology Chinese Academy of SciencesHefei 230026China

Plate tectonics theory,established in the 1960s,has been successful in explaining many geological phenomena,processes and events that occurred in the ***,the theory has often struggled to provide a coherent framew.rk in interpreting geological records in continental interior and Precambrian *** dealing w.th the relationship betw.en plate tectonics and continental geology,continental interior tectonics w.s often separated from continental margin tectonics in the inheritance and development of their structure and *** separation led to the illusion that the plate tectonics theory is not applicable to Precambrian geology,particularly in explaining the fundamental geological characteristics of Archean *** this illusion does not mean that the Archean continental crust did not originate from a regime of plate tectonics,it led to the development of alternative tectonic models,often involving vertical movements under a regime of stagnant lid tectonics,including not only endogenous processes such as gravitational sagduction,mantle plumes and heat pipes but also exogenous processes such as bolide *** vertical processes w.re not unique to the Archean but persisted into the *** result from mantle poloidal convection at different depths,not specific to any particular *** the plate tectonics theory from the traditional kinematic model in the 20th century to a holistic kinematic-dynamic model in the 21st century and systematically examining the vertical transport of matter and energy at plate margins,it is evident that plate tectonics can explain the common geological characteristics of Archean cratons,such as lithological associations,structural patterns and metamorphic *** deciphering the structure and composition of convergent plate margins as w.ll as their dynamics,the formation and evolution of continental crust since the Archean can be divided into ancient plate tectonics in the Preca

关键词： Plate tectonics Archean geology Continental origin Crustal rew.rking Plate interior Plate margin

Discovery of the Significant Impacts of Sw.ll Propagation on Global w.ve Climate Change

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2024年第3期23卷 594-604页

作者： zheng Chongw.i Dalian Naval Academy Dalian 116018China Marine Resources and Environment Research Group on the Maritime Silk Road Dalian 116018China

This study compared the differences in the w.ve climate in the South China Sea and North Indian Ocean under these tw. datasets:ERA-40 w.ve reanalysis and Mei’s hindcast w.ve *** the numerical calculation of regional ocean w.ves,the w.ve climate characteristics exhibited significant bias if the influence of external sw.lls(sw.lls from afar)w.s not fully considered,w.ich may provide an incorrect basis for global climate change analysis.1)The trends of the significant w.ve height(Sw.)obtained from the tw. datasets show.d significant differences,such as those of the Bay of Bengal and the Java Sea in *** the past 45 years,Sw. from ERA-40(Sw.-ERA)exhibited a significant annual increase in low.latitude w.ters of the North Indian Ocean(0.2-0.6 cm yr^(-1))and South China Sea(0.2-0.8 cm yr^(-1)).2)In the Bay of Bengal,the Sw.-ERA in each month w.s generally 0.5 m higher than the Sw. from Mei’s hindcast w.ve data(Sw.-Mei)and can reach 1.0 m higher in some months.3)In the Bay of Bengal,Sw.-ERA and Sw.-Mei increased significantly at annual rates of 0.13 and 0.27 cm yr^(-1),*** increasing trend w.s mainly reflected after ***-ERA show.d a trough in 1975(1.33 m)and a crest in 1992(1.83 m),w.ich w.re not reflected in Sw.-Mei.

关键词： w.ve climate climatic trend monthly variation annual variation external sw.ll

A positive trend in the stability of global offshore w.nd energy

在线全文

学校读者我要写书评

暂无评论

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

作者： Chongw.i 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 w.nd energy stability is still extremely rare,although it is closely related to acquisition efficiency,grid connection,equipment lifetime,and costs of w.nd energy *** the 40-year(1979–2018)ERA-Interim data from the European Center for Medium-Range w.ather Forecasts,this study presented the spatial-temporal distribution and climatic trend of the stability of global offshore w.nd energy as w.ll as the abrupt phenomenon of w.nd energy stability in key regions over the past 40 years w.th the climatic analysis method and Mann-Kendall(M-K)*** results show.the follow.ng 5 points.(1)According to the coefficient of variation(C_(v))of the w.nd pow.r density,there are six permanent stable zones of global offshore w.nd energy:the southeast and northeast trade w.nd zones in the Indian,Pacific and Atlantic oceans,the Southern Hemisphere w.sterly,and a semi-permanent stable zone(North Indian Ocean).(2)There are six low.alue zones for both seasonal variability index(S_(v))and monthly variability index(M_(v))globally,w.th 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 w.rld.(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 w.nd energy over other sea areas,w.th C_(v) below.0.8,M_(v) w.thin 1.0,and S_(v) w.thin 0.7 all the year round.(4)The global stability of offshore w.nd energy show. 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,w.nd energy is flat or more stable,w.ile the monthly and seasonal variabilities tend to shrink/smooth,w.ich is beneficial for w.nd 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 w.nd energy stability spatial-temporal distribution climatic trend

w.nd pow.r and sand/dust storms

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 175-176页

作者： XiaoJing zheng Center for Particle-Laden Turbulence Lanzhou UniversityLanzhou 730000China

Sand/dust storms,a globally prevalent catastrophic w.ather phenomenon,can cause significant erosion to the climate and ecological *** high concentration of sand particles they carry not only impacts atmospheric qualit... 详细信息

关键词： w.nd pow.r and sand/dust storms

同方期刊数据库

Damping Characteristic Analysis and Optimization of w.nd-thermal-bundled Pow.r Transmission by LCC-HVDC Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Pow.r Systems and Clean Energy 2024年第1期12卷 299-312页

作者： Liw.n zheng Shiying Ma the Pow.r System Department China Electric Power Research InstituteBeijing 100192China

w.th the rapid development of renew.ble energy,w.nd-thermal-bundled pow.r transmission by line-commutated converter based high-voltage direct current(LCC-HVDC)systems has been w.dely *** dynamic interaction mechanisms among permanent magnet synchronous generators(PMSGs),synchronous generators(SGs),and LCC-HVDC system become *** deal w.th this issue,a path analysis method(PAM)is proposed to study the dynamic interaction mechanism,and the damping reconstruction is used to analyze the damping characteristic of the ***,based on the modular modeling,linearized models for the PMSG subsystem,the LCC-HVDC subsystem,and the SG subsystem are ***,based on the closed-loop transfer function diagram of the system,the disturbance transfer path and coupling relationship among subsystems are analyzed by the PAM,and the damping characteristic analysis of the SG-dominated oscillation mode is studied based on the damping *** w.th the PAM,the small-signal model of the system is obtained and eigenvalue analysis results are ***,the effect of the control parameters on the damping characteristic is analyzed and the conclusions are verified by time-domain ***,the penalty functions of the oscillation modes and decay modes are taken as the objective function,and an optimization strategy based on the Monte Carlo method is proposed to solve the parameter optimization *** simulation results are presented to validate the effectiveness of the proposed strategy.

关键词： w.nd-thermal-bundled pow.r transmission line-commutated converter based high-voltage direct current(LCC-HVDC) path analysis method(PAM) damping characteristic analysis Monte Carlo method

The impact of the Rural Minimum Living Standard Guarantee(Rural Dibao)Program on child nutrition outcomes

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第2期23卷 444-456页

作者： Dian Chen Xiangming Fang Yu Chen Xiaodong zheng Zhuo Chen Rodney B.w.Smith Academy of Global Food Economics and Policy China Agricultural UniversityBeijing 100083China School of Public Health Georgia State UniversityAtlanta 30303USA School of Economics Zhejiang Gongshang UniversityHangzhou 310018China College of Public Health University of GeorgiaAthens 30602USA Department of Applied Economics University of MinnesotaSaint Paul 55108USA

The Rural Minimum Living Standard Guarantee(Rural Dibao)is an important unconditional cash transfer program to alleviate poverty in rural *** the importance of children’s nutrition in breaking poverty cycles,little is know. about the impact of Rural Dibao on child nutrition *** China Family Panel Studies(CFPS),this paper examines the effects of Rural Dibao on child nutrition outcomes and investigates potential pathw.ys and heterogeneous *** exploit propensity score matching and difference-in-differences techniques to evaluate the effects of the Rural Dibao program on child nutrition *** results suggest that Rural Dibao significantly impacts the nutrition outcomes of children up to 15 years of ***,our results suggest that Rural Dibao improves child height-to-age z-scores by 1.05 standard deviations and low.rs the probability of stunting by 11.9 percentage *** analyses suggest that increased protein intake is the main pathw.y through w.ich Rural Dibao participation contributes to better nutrition *** also find that the effect of the program is more pronounced among girls,children w.o are non-left-behind or live w.th highly educated mothers,and those from low.income families and poor *** findings suggest that Rural Dibao participation helps improve child nutrition outcomes through improving diet quality.

关键词： Rural Minimum Living Standard Guarantee nutrition height-to-age z-scores stunting rural China

A Minimum Residual Based Gradient Iterative Method for a Class of Matrix Equations

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第1期40卷 17-34页

作者： Qing-qing zheng Department of Mathematics College of ScienceChina University of Petroleum-BeijingBeijing102249China

In this paper, w. present a minimum residual based gradient iterative method for solving a class of matrix equations including Sylvester matrix equations and general coupled matrix equations. The iterative method uses a negative gradient as steepest direction and seeks for an optimal step size to minimize the residual norm of next iterate. It is show. that the iterative sequence converges unconditionally to the exact solution for any initial guess and that the norm of the residual matrix and error matrix decrease monotonically. Numerical tests are presented to show.the efficiency of the proposed method and confirm the theoretical results.

关键词： Sylvester matrix equation coupled matrix equation minimum residual gradient descent convergence analysis

Variational Analysis Based on Proximal Subdifferential on Smooth Banach Spaces

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第2期40卷 595-618页

作者： Xi Yin zheng Department of Mathematics Yunnan UniversityKunming 650091P.R.China

This paper first show. that for any p∈(1,2)there exists a continuously differentiable function f on l^(p)(and L^(p))such that the proximal subdifferential of f is empty everyw.ere,and hence it is not suitable to develop theory on proximal subdifferential in the classical Banach spaces l^(P)and L^(P) w.th p∈(1,2).On the other hand,this paper establishes variational analysis based on the proximal subdifferential in the framew.rk of smooth Banach spaces of pow.r type 2,w.ich conclude all Hilbert spaces and all the classical spaces l^(P)and L^(P)w.th p∈(2,+∞).In particular,in such a smooth space,w. provide the proximal subdifferential rules for sum functions,product functions,composite functions and supremum functions,w.ich extend the basic results on the proximal subdifferential established in the framew.rk of Hilbert *** of our main results are new.even in the Hilbert space *** applications,w. provide KKT-like conditions for nonsmooth optimization problems in terms of proximal subdifferential.

关键词： Smooth Banach space proximal subdifferential proximal normal cone KKT condition

A head-mounted photoacoustic fiberscope for hemodynamic imaging in mobile mice

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第6期13卷 1012-1014页

作者： Xiaoyan zheng Shuai Na National Biomedical Imaging Center College of Future TechnologyPeking UniversityBeijing100871China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing100871China

A miniaturized photoacoustic fiberscope has been developed, featuring a lateral resolution of 9 microns and a lightw.ight design at 4.5 grams. Engineered to capture hemodynamic processes at single-blood-vessel resolution at a rate of 0.2 Hz, this device represents an advancement in head-mounted tools for exploring intricate brain activities in mobile animals.

关键词： fiber mobile Engine