检索结果-南通市图书馆

Effect of heat treatment on the microstructure,mechanical properties and fracture behaviors of ultra-high-strength SiC/Al-Zn-Mg-Cu composites

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and materials 2024年第10期31卷 2233-2243页

作者： Guonan ma Shize Zhu Dong Wang Peng xue Bolüxiao Zongyi ma Shi-changxu Innovation Center for Advanced materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Centre of Excellence for Advanced materials Dongguan 523808China

A high-zinc composite,12vol%SiC/Al-13.3 Zn-3.27 Mg-1.07Cu(wt%),with an ultra-high-strength of 781 MPa was success-fully fabricated through a powder metallurgy method,followed by an extrusion *** effects of solid-solution and aging heat treat-ments on the microstructure and mechanical properties of the composite were extensively *** with a single-stage sol-id-solution treatment,a two-stage solid-solution treatment(470℃/1 h+480℃/1 h)exhibited a more effective solid-solution strengthen-ing owing to the higher degree of solid-solution and a more uniform *** to the aging hardness curves of the com-posite,the optimized aging parameter(100℃/22 h)was *** the aging temperature and time resulted in finer and more uniform nanoscale precipitates but only yielded a marginal increase in tensile *** fractography analysis revealed that intergranu-lar cracking and interface debonding were the main fracture mechanisms in the ultra-high-strength SiC/Al-Zn-Mg-Cu *** regions,such as the SiC/Al interface containing numerous compounds and the precipitate-free zones at the high-angle grain boundaries,were identified as significant factors limiting the strength enhancement of the *** compounds,including MgO,MgZn2,and Cu5Zn8,reduced the interfacial bonding strength,leading to interfacial debonding.

关键词： metal matrix composites heat treatment interfacial reaction mechanical properties fracture mechanism

Catalysis by subsurface metal atoms in Al(001) through electron transfer

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第4期11卷 12-13页

作者： Bo Sun Ding ma Beijing National Laboratory for Molecular Science New Cornerstone Science Laboratory College of Chemistry and Molecular Engineering Peking University

Heterogeneous catalysis plays a crucial role in the chemical industry, which has evolved from the investigation of chemisorption to an electronic structure[1]. Diverse strategies, such as alloying,doping, and confining, have been applied to enhance the catalytic properties of active sites through electronic modulation. The electron transfer between active sites and substrates profoundly influences catalytic activity [2].

关键词：

Spatial Distribution Pattern and Influencing Factors of Bed-and-breakfasts(B&Bs)from the Perspective of Urban-rural Differences:A Case Study of Jiaodong Peninsula,China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Geographical Science 2024年第4期34卷 752-763页

作者： WANG xinyue ma Qian management College Ocean University of ChinaQingdao 266100China

There are significant differences between urban and rural bed-and-breakfasts(B&Bs)in terms of customer positioning,economic strength and spatial *** identifying the differences in spatial characteristics and influencing factors of each type,is essential for creating urban and rural B&B agglomeration *** study used density-based spatial clustering of applications with noise(DBSCAN)and the multi-scale geographically weighted regression(MGWR)model to explore similarities and differences in the spatial distribution patterns and influencing factors for urban and rural B&Bs on the Jiaodong Peninsula of China from 2010 to *** results showed that:1)both urban and rural B&Bs in Jiaodong Peninsula went through three stages:a slow start from 2010 to 2015,rapid development from 2015 to 2019,and hindered development from 2019 to ***,urban B&Bs demonstrated a higher development speed and agglomeration intensity,leading to an increasingly evident trend of uneven development between the two sectors.2)The clustering scale of both urban and rural B&Bs continued to expand in terms of quantity and *** B&B clusters characterized by a limited number,but a higher likelihood of transitioning from low-level to high-level *** the number of rural B&B clusters steadily increased over time,their clustering scale was comparatively lower than that of urban B&Bs,and they lacked the presence of high-level clustering.3)In terms of development direction,urban B&B clusters exhibited a relatively stable pattern and evolved into high-level clustering centers within the main urban ***,rural B&Bs exhibited a more pronounced spatial diffusion effect,with clusters showing a trend of multi-center development along the coastline.4)Transport emerged as a common influencing factor for both urban and rural B&Bs,with the density of road network having the strongest explanatory power for their spatial *** terms of differences,populati

关键词： urban-rural bed-and-breakfasts(B&Bs) spatiotemporal evolution density-based spatial clustering of applications with noise(DBSCAN)model multi-scale geographically weighted regression(MGWR) Jiaodong Peninsula China

Quantifying Contribution of Recycled Moisture to Precipitation in Temperate Glacier Region,Southeastern Tibetan Plateau,China

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2024年第4期34卷 764-776页

作者： ma Yanwei PU Tao SHI xiaoyi ma xinggang YU Hongmei College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-environment and ResourcesChinese Academy of SciencesLanzhou 730000China

Recycled moisture is an important indicator of the renewal capacity of regional water *** to the existence of Yulong Snow Mountain,Lijiang in Yunnan Province,southeast of the Qinghai-Tibet Plateau,China,is the closest ocean glacier area to the equator in *** precipitation samples were collected from 2017 to 2018 in Lijiang to quantify the effect of sub-cloud evaporation and recycled moisture on precipitation combined with the d-excess model during monsoon and non-monsoon *** results indicated that the d-excess values of precipitation fluctuated between–35.6‰and 16.0‰,with an arithmetic mean of 3.5‰.The local meteoric water line(LMWL)wasδD=7.91δ^(18)O+2.50,with a slope slightly lower than the global meteoric water line(GMWL).Subcloud evaporation was higher during the non-monsoon season than during the monsoon *** tended to peak in march and was primarily influenced by the relative *** source of the water vapour affected the proportion of recycled *** to the results of the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,the main sources of water vapour in Lijiang area during the monsoon period were the southwest and southeast *** the non-monsoon period,water vapour was transported by a southwesterly *** recycled moisture in Lijiang area between march and October 2017 was 10.62%.Large variations were observed between the monsoon and non-monsoon seasons,with values of 5.48%and 25.65%,*** differences were primarily attributed to variations in the advection of water *** recycled moisture has played a supplementary role in the precipitation of Lijiang area.

关键词： recycled moisture stable isotope precipitation d-excess Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model southeastern Tibetan Plateau China

Effects of baffle position in serpentine flow channel on the performance of proton exchange membrane fuel cells

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第5期69卷 250-262页

作者： Guodong xia xiaoya Zhang Dandan ma MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of TechnologyBeijing 100124China

This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstream(Case 3),downstream(Case 4),and the entire cathode flow channel(Case 5)to study the effects of baffle position on mass transport,power density,net power,***,the effects of back pressure and humidity on the voltage were *** showed that compared to smooth channels,the oxygen and water transport facilitation at the diffusion layer-channel interface were added 11.53%-20.60%and 7.81%-9.80%at 1.68 A·cm^(-2)by adding *** closer the baffles were to upstream,the higher the total oxygen flux,but the lower the flux uniformity the worse the water *** oxygen flux of upstream baffles was 8.14%higher than that of downstream baffles,but oxygen flux uniformity decreased by 18.96%at 1.68 A·cm^(-2).The order of water removal and voltage improvement was Case 4>Case 5>Case 3>Case 2>Case *** power of Case 4 was 9.87%higher than that of the smooth *** the Case 4,when the cell worked under low back pressure or high humidity,the voltage increments were *** potential increment for the back pressure of 0 atm was 0.9%higher than that of 2 atm(1 atm=101.325 kPa).The potential increment for the humidity of 100%was 7.89%higher than that of 50%.

关键词： Proton exchange membrane fuel cell Baffle position mass transfer Net power Uniformity Voltage increment

Scientific and technological innovations of wastewater treatment in China

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第6期18卷 43-48页

作者： Hui Huang Rui ma Hongqiang Ren State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023China

The“dual-carbon”strategy promotes the development of the wastewater treatment sector and is an important tool for leading science and technology *** on the global climate change and the new policies introduced by China,this paper described the new needs for the development of wastewater treatment science and *** offered a retrospective analysis of the historical trajectory of scientific and technological advancements in this *** bibliometrics,it delineated the research hotspots within wastewater treatment,notably highlighting materials genomics,artificial intelligence,and synthetic ***,it posited that,in the future,the field of wastewater treatment should follow the paths of technological innovations with multi-dimensional needs,such as carbon reduction,pollution reduction,health,standardisation,and *** purpose of this paper was to provide references and suggestions for scientific and technological innovations in the field of wastewater treatment,and to contribute to the common endeavor of moving toward a Pollution-Free Planet.

关键词： Wastewater treatment Dual-carbon strategy Technological innovation Carbon reduction

A new method for evaluating wedges of steel plates and strips

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第7期31卷 1719-1735页

作者： xiao-bao ma xiao-xin ma Tao Wang Zhong-kai Ren Yu-cheng Ren College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024ShanxiChina Ministry of Education Engineering Research Center of Advanced Metal Composite Forming Technology and Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina China National Heavy machinery Research Institute Co. Ltd.Xi'an 710018ShaanxiChina Faculty of Mechanical Engineering Hebei University of ArchitectureZhangjiakou 075000HebeiChina

To overcome the inaccuracy problem of the traditional wedge evaluation of steel plates and strips caused by the ran-domness of the thicknesses of two local points and improve the reliability of the wedge index,the double-centroid method for the wedge evaluation was proposed,and a model based on the centroid theory was ***,an integral model for the discrete thickness values of the cross-section profiles was *** discussion focused on the distinct characteristics of the two-point method,asymmetric method,and double-centroid method in evaluating the asymmetric distribution of *** three methods were employed to evaluate the wedge values of both the theoretical and measured cross-sections of steel plates and strips,and the accuracies of three wedge evaluation models were analyzed and *** results showed that the double-centroid method objectively reflects the degree and variation characteristics of the wedge values of the cross-sections of steel plates and strips,and this method is feasible,reliable,and outstanding.

关键词： Steel plate and strip Wedge Two-point method Double-centroid method Reliability

Partial regularity and nonlinear potential estimates for Stokes systems with super-quadratic growth

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China mathematics 2024年第7期67卷 1525-1554页

作者： Lingwei ma Zhenqiu Zhang School of mathematical Sciences Tianjin Normal UniversityTianjin300387China School of mathematical Sciences and LPMC Nankai UniversityTianjin300071China

This paper builds a bridge between partial regularity theory and nonlinear potential theory for the following generalized stationary Stokes system with super-quadratic growth and continuous coefficients:-div A(x,Du)+■π=f,div u=0,where Du is the symmetric part of the gradient■*** first establish anε-regularity criterion involving both the excess functional of the symmetric gradient Du and Wolff potentials of the nonhomogeneous term f to guarantee the local vanishing mean oscillation(VMO)-regularity of Du in an open subset Ω_(u) of Ω with full *** anε-regularity criterion leads to a pointwise Wolff potential estimate of Du,which immediately infers that Du is partially C^(0)-regular under appropriate ***,we give a local continuous modulus estimate of Du.

关键词： nonlinear Stokes system partial regularity Wolff potential estimates continuous modulus estimates

Take Every Step Firmly with Sharp Eyes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第10期42卷 1065-1066页

作者： Shengming ma Chinese Journal of Chemistry

Chinese Journal of Chemistry(CJC)is committed to becoming a prominent international journal for chemistry and the related *** are working very hard towards this *** offers a diverse range of manuscript types,including... 详细信息

关键词： journal becoming diverse