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PREPARAtION OF MESOPOROUS CARBON BY CARBON DIOXIDE ACtIVAtION WItH CAtALYSt

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 67-72页

作者： W.Z. Shen A.H. Lu J.t. zheng Institute of Coal Chemistry The Chinese Academy of Sciences Taiyuan 030001 China

A mesoporous activated carbon (AC) can be successfully prepared by catalytic activation with carbon dioxide. For iron oxide as catalyst, there were two regions of mesopore size distribution, i.e. 2-5nm and 30-70nm. When copper oxide or magnesium oxide coexisted with iron oxide as composite catalyst, the content of pores with sizes of 2-5nm was decreased, while the pores with 30-70nm were increased significantly. For comparison, AC reactivated by carbon dioxide directly was also investigated. It was shown that the size of mesopores of the resulting AC concentrated in 2-5nm with less volume. the adsorption of Congo red was tested to evaluate the property of the result-ing AC. Furthermore, the factors affecting pore size distribution and the possibility of mesopore formation were discussed.

关键词： activated carbon mesopore. catalytic activation

Plate tectonics in the Archean:Observations versus interpretations

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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 framework in interpreting geological records in continental interior and Precambrian *** dealing with the relationship between plate tectonics and continental geology,continental interior tectonics was 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 were 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 well 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 reworking Plate interior Plate margin

Discovery of the Significant Impacts of Swell Propagation on Global Wave Climate Change

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

作者： zheng Chongwei 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 wave climate in the South China Sea and North Indian Ocean under these two datasets:ERA-40 wave reanalysis and Mei’s hindcast wave *** the numerical calculation of regional ocean waves,the wave climate characteristics exhibited significant bias if the influence of external swells(swells from afar)was not fully considered,which may provide an incorrect basis for global climate change analysis.1)the trends of the significant wave height(SWH)obtained from the two datasets showed significant differences,such as those of the Bay of Bengal and the Java Sea in *** the past 45 years,SWH from ERA-40(SWH-ERA)exhibited a significant annual increase in low-latitude waters 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 SWH-ERA in each month was generally 0.5 m higher than the SWH from Mei’s hindcast wave data(SWH-Mei)and can reach 1.0 m higher in some months.3)In the Bay of Bengal,SWH-ERA and SWH-Mei increased significantly at annual rates of 0.13 and 0.27 cm yr^(-1),*** increasing trend was mainly reflected after ***-ERA showed a trough in 1975(1.33 m)and a crest in 1992(1.83 m),which were not reflected in SWH-Mei.

关键词： wave climate climatic trend monthly variation annual variation external swell

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

Comparative analyses of mitogenomes in the social bees with insights into evolution of long inverted repeats in the Meliponini

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Zoological Research 2024年第1期45卷 160-175页

作者： Yu-Ran Li zheng-Wei Wang Richard t.Corlett Wen-Bin Yu Yunnan Key Laboratory for the Conservation of tropical Rainforests and Asian Elephants&Center for Integrative Conservation Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China CAS Key Laboratory of tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China Southeast Asia Biodiversity Research Institute Chinese Academy of SciencesMenglaYunnan 666303China University of Chinese Academy of Sciences Shijingshan DistrictBeijing 100049China

the insect mitogenome is typically a compact circular molecule with highly conserved gene ***,mitogenome structural variations have been reported in specific taxa,and gene rearrangements,usually the tRNAs,occur in different *** synapomorphies of mitogenome organizations can provide information for phylogenetic inferences,comparative analyses of mitogenomes have been given increasing ***,most studies use a very few species to represent the whole genus,tribe,family,or even order,overlooking potential variations at lower taxonomic levels,which might lead to some incorrect *** provide new insights into mitogenome organizations and their implications for phylogenetic inference,this study conducted comparative analyses for mitogenomes of three social bee tribes(Meliponini,Bombini,and Apini)based on the phylogenetic framework with denser taxonomic sampling at the species and population *** analyses revealed that mitogenomes of Apini and Bombini are the typical type,while those of Meliponini show diverse variations in mitogenome sizes and *** inverted repeats(IRs)cause significant gene rearrangements of protein coding genes(PCGs)and rRNAs in Indo-Malay/Australian stingless bee *** evolution analyses showed that the lineage with IRs have lower dN/dS ratios for PCGs than lineages without IRs,indicating potential effects of IRs on the evolution of mitochondrial *** finding of IRs and different patterns of gene rearrangements suggested that Meliponini is a hotspot in mitogenome *** conserved PCGs and rRNAs whose rearrangements were found only in the mentioned lineages within Meliponini,tRNA rearrangements are common across all three tribes of social bees,and are significant even at the species level,indicating that comprehensive sampling is needed to fully understand the patterns of tRNA rearrangements,and their implications for phylogenetic inference.

关键词： Social bees Phylogeny Mitogenome structure Gene rearrangement Inverted repeats

Wind power and sand/dust storms

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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 weather 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： Wind power and sand/dust storms

Fatigue-resistant sliding ferroelectricity

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Science China Materials 2024年第10期67卷 3417-3418页

作者： zheng Liu School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore

the direction of spontaneous polarization in ferroelectricity can be reoriented by an external electric *** special feature of ferroelectricity is important candidates for fabricating advanced nonvolatile random-access memory[1].However,repeatedly switching polarization induces the ferroelectric device performance degenerates due to a reduction of polarization.

关键词： polarization ferroelectric field.

Damping Characteristic Analysis and Optimization of Wind-thermal-bundled Power transmission by LCC-HVDC Systems

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

作者： Liwen zheng Shiying Ma the Power System Department China Electric Power Research InstituteBeijing 100192China

With the rapid development of renewable energy,wind-thermal-bundled power transmission by line-commutated converter based high-voltage direct current(LCC-HVDC)systems has been widely *** dynamic interaction mechanisms among permanent magnet synchronous generators(PMSGs),synchronous generators(SGs),and LCC-HVDC system become *** deal with 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 *** with 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： Wind-thermal-bundled power transmission line-commutated converter based high-voltage direct current(LCC-HVDC) path analysis method(PAM) damping characteristic analysis Monte Carlo method

Variational Analysis Based on Proximal Subdifferential on Smooth Banach Spaces

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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 shows 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 everywhere,and hence it is not suitable to develop theory on proximal subdifferential in the classical Banach spaces l^(P)and L^(P) with p∈(1,2).On the other hand,this paper establishes variational analysis based on the proximal subdifferential in the framework of smooth Banach spaces of power type 2,which conclude all Hilbert spaces and all the classical spaces l^(P)and L^(P)with p∈(2,+∞).In particular,in such a smooth space,we provide the proximal subdifferential rules for sum functions,product functions,composite functions and supremum functions,which extend the basic results on the proximal subdifferential established in the framework of Hilbert *** of our main results are new even in the Hilbert space *** applications,we 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