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Synergistic effects of multiscale TiC and dual-phase structure on tensile properties of particle-reinforced steel

Journal of Iron and Steel Research International 2024年第5期31卷 1232-1245页

作者： Ye jia.Xiang-tao Deng Qi Wang Cheng-ru Li Hao Wu zhao-dong Wang State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina

The conventional melting methods were used to obtain in situ TiC particle-reinforced dual-phase steel,followed by hot rolling and heat treatment *** aim was to investigate the effect of TiC particles on the fracture behavior of dual-phase steel at different annealing temperatures,by analyzing the microstructure and tensile behavior of the multiscale TiC particle-reinforced dual-phase *** results showed that TiC particles precipitated in the as-cast microstructure of dual-phase steel were distributed along the grain *** hot rolling,the grain boundary-like morphology of the micron-sized TiC particles was disrupted,and the particles became more refined and evenly distributed in the *** tensile tests revealed that the strength of the TiC particle-reinforced dual-phase steel increased with increasing martensite content,while the elongation *** results were similar to those of conventional *** addition of 1 vol.%multiscale TiC particles improved the strength of the dual-phase steel but did not affect elongation of the *** and holes were primarily concentrated around the TiC particles rather than at the interface of martensite and *** main causes of crack sprouting were TiC particle interface cracking and TiC particle internal ***,the study demonstrated the potential of multiscale TiC particle-reinforced dual-phase steel as a strong and tough *** refined distribution of TiC particles in the matrix improved the strength of the material without compromising its *** results also highlighted the importance of careful selection of reinforcement particles to avoid detrimental effects on the fracture behavior of the material.

关键词： TiC particle Dual-phase structure TiC-reinforced dual-phase steel Tension Fracture behavior

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Switching Frequency Improvement of a High Speed on/off Valve Based on Pre-excitation Control Algorithm

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 94-106页

作者： Qi zhong Xiaotian Li Yongxin Mao Enguang Xu Tiwei jia.Yanbiao Li Huayong Yang College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310023China

The high-speed on/off valve(HSV)serves as the fundamental component responsible for generating discrete fluids within digital hydraulic *** the switching frequency of the HSV increases,the properties of the generated discrete fluid approach those of continuous ***,a higher frequency response characteristic of HSV is the key to ensure the control accuracy of digital hydraulic ***,the current research mainly focuses on its dynamic performance,but neglect its *** paper presents a theoretical analysis demonstrating that the FRC of the HSV can be enhanced by minimizing its switching *** maximum switching frequency(MSF)is mainly determined by opening dynamic performance when HSV operates with low switching duty ratio(SDR),whereas the closing dynamic performance limits the MSF when HSV operates with high *** upon these findings,the pre-excitation control algorithm(PECA)is proposed to reduce the switching time of the HSV,and consequently enhance its *** results demonstrate that PECA shortens the opening delay time of HSV by 1.12 ms,the closing delay time by 2.54 ms,and the closing moving time by 0.47 ms in comparison to the existing advanced control *** a result,a larger MSF of 417 Hz and a wider controllable SDR range from 20%to 70%were achieved at a switching frequency of 250 ***,the proposed PFCA in this paper has been verified as an effective and promising approach for enhancing the control performance of digital hydraulic systems.

关键词： High speed on/off valve Switching frequency Pre-excitation Dynamic performance Switching duty ratio

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Variability of urban fractional vegetation cover and its driving factors in 328 cities in China

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Science China Earth Sciences 2024年第2期67卷 466-482页

作者： Fei FENG Xin YANG Baoquan jia.Xiaoting LI Xianwen LI Chengyang Xu Kaicun WANG Research Centre of urban Forestry Key Laboratory for Silviculture and Forest Ecosystem of State Forestry and Grassland AdministrationBeijing Forestry UniversityBeijing100083China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China Research Institute of Forestry Chinese Academy of ForestryBeijing100091China School of Architecture Tsinghua UniversityBeijing100084China College of urban and Environmental Sciences Sino-French Institute for Earth System ScienceInstitute of Carbon NeutralityPeking UniversityBeijing100871China

urban green space promotes the health of urban residents,enhances urban ecosystem biodiversity,mitigates environmental pollution,and attenuates urban heat island ***,urban vegetation cover is highly heterogeneous and difficult to *** this study,the variation of urban fractional vegetation cover(FVC)in 328 cities in China from 1990 to2022 was quantified based on Landsat satellite data at a 30-m *** was found that from 1990 to 2005,due to increases in building density and impervious surfaces in cities,the national mean urban vegetation cover decreased from 0.38 to ***2005,urban vegetation cover began to reverse,reaching 0.45 in *** increasing trend was most pronounced in newly built urban *** decrease in average urban vegetation cover before 2005 was mainly due to the expansion of low vegetation cover areas,while the increase in urban vegetation cover after 2005 manifested as the expansion of high vegetation cover *** reversal in the trend of urban vegetation cover change after 2004 is related to the gradual implementation of national policies requiring increased urban green space *** urban gross domestic product(GDP)showed the highest correlation with changes in urban vegetation *** large and medium-sized cities,the top three factors influencing vegetation cover were GDP,urban population,and ***,for cities in arid/semi-arid regions,changes in vegetation cover were more sensitive to climatic factors(such as precipitation).Although the urban vegetation cover in China has substantially increased in recent years,the urban green space in small-sized cities and in the old urban districts of large-sized cities still have room to improve.

关键词： urban vegetation urban vegetation cover urbanization Remote sensing

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Heat stress affects mammary metabolism by influencing the plasma flow to the glands

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Journal of Animal Science and Biotechnology 2024年第5期15卷 1908-1917页

作者： jia.Zeng Diming Wang Huizeng Sun Hongyun Liu Feng‑Qi zhao jia.xin Liu Institute of Dairy Science College of Animal SciencesZhejiang UniversityHangzhouChina zhejia.g Key Laboratory of Dairy Cow Genetic Improvement and Milk Quality Research Zhejiang UniversityHangzhouChina Department of Animal&Veterinary Sciences University of VermontBurlingtonVTUSA

Background Environmental heat stress(HS)can have detrimental effects on milk production by compromising the mammary *** plasma flow(MPF)plays a crucial role in nutrient supply and uptake in the mam-mary *** this experiment,we investigated the physiological and metabolic changes in high-yielding cows exposed to different degrees of HS:no HS with thermal-humidity index(THI)below 68(No-HS),mild HS(Mild-HS,68≤THI≤79),and moderate HS(Mod-HS,79ural *** study focused on the changes in blood oxygen supply and mammary glucose uptake and *** Compared with No-HS,the MPF of dairy cows was greater(Punder Mild-HS,but was lower(Punder *** supply and consumption exhibited similar changes to the MPF under different HS,with no difference in ratio of oxygen consumption to supply(P=0.46).The mammary arterio-vein differences in glucose concentration were lower(Punder Mild-and Mod-HS than under no *** supply and flow were significantly increased(Punder Mild-HS but significantly decreased(Punder Mod-HS compared to *** uptake(Puced under Mod-HS compared to those under No-HS and *** Mild-HS,there was a significant decrease(Pucose supply compared to that under No-HS and Mod-HS,with no difference(P=0.53)in the ratio of lactose yield to uptaken glucose among different HS *** Degrees of HS exert different influences on mammary metabolism,mainly by altering MPF in dairy *** output from this study may help us to develop strategies to mitigate the impact of different degrees of HS on milk production.

关键词： Dairy cow Heat stress Mammary metabolism Mammary plasma flow

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Online Consensus Control of Nonlinear Affine Systems From Disturbed Data

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 551-553页

作者： Yifei Li Wenjie Liu jia. Sun Chen Chen jia.zhang Gang Wang National Key Laborary of Autonomous Intelligent unmanned Systems Beijing Institute of TechnologyBeijing 100081 Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Dear Editor,In this letter, we introduce a novel online distributed data-driven robust control approach for learning controllers of unknown nonlinear multi-agent systems(MASs) using state-dependent representations.

关键词： agent online Online

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Electricity-Heat-Based Integrated Demand Response Considering Double Auction Energy Market with Multi-Energy Storage for Interconnected Areas

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1688-1700页

作者： Dan Wang Deyu Huang Qing'e Hu Hongjie jia.Bo Liu Yang Lei Key Laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjin 300072China Key Laboratory of Smart Energy&Information Technology of Tianjin Municipality Tianjin 30072China

With development of integrated energy systems and energy markets,transactive energy has received increasing attention from society and academia,and realization of energy distribution and integrated demand response through market transactions has become a current research *** on optimized operation of a distributed energy station as a regional energy supply center is of great significance for improving flexibility and reliability of the *** on retail-side energy trading market,this study first establishes a framework of combined electric and heating energy markets and analyses a double auction market mechanism model of interconnected distributed energy *** study establishes a mechanism model of energy market participants,and establishes the electric heating combined market-clearing model to maximize global surplus considering multi-energy ***,in the case study,a typical user energy consumption scenario in winter is selected,showing market-clearing results and demand response effects on a typical *** of transmission line constraints,energy supply equipment capacity,and other factors on clearing results and global surplus are compared and analyzed,verifying the effects of the proposed method on improving global surplus,enhancing interests of market participants and realizing coordination and optimal allocation of both supply and demand resources through energy complementarity between regions.

关键词： Double auction energy market integrated energy system interconnected energy stations multi-energy storage

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The effect of Ti and Zr content on the structure,mechanics and energy-release characteristics of Ti—Zr—Ta alloys

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Defence Technology（防务技术） 2024年第1期31卷 343-350页

作者： jia.yu Meng Jing-zhi He Bin zhang Jin Chen Shun Li Dun Niu Yu Tang Xi’an Modern Chemistry Research Institute Xi'an710065China College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073China

Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage *** this work the microstructure,mechanical properties and energy release characteristics of multi-element Ti-Zr-Ta alloys with good casting performance were *** microstructure of the Ti_(x)ZrTa alloys gradually change from BCC+HCP to single BCC structure with the increase of *** the Ti_(2)Zr_(y)Ta alloys was still uniform and single BCC structure with the increase of *** evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of Ti-Zr-Ta *** synergistic effect of dual phase structure increases the fracture strain of Ti_(x)ZrTa(x=0.2,0.5)with the Ti content decreases,while the fracture strain of Ti_(x)ZrTa(x=2.0,3.0,4.0)gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation *** as Zr content increases,the fracture strain of Ti_(2)Zr_(y)Ta alloys decrease,then the oxidation reaction rate and fragmentation degree gradually *** higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of Ti_(x)ZrTa alloys with low Ti content and Ti_(2)Zr_(y)Ta alloys with high Zr content.

关键词： Energetic structural materials Ti-Zr-Ta Multi-element alloy Energy release characteristics

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Pd Pt VO_(x)/CeO_(2)-ZrO_(2):Highly efficient catalysts with good sulfur dioxide-poisoning reversibility for the oxidative removal of ethylbenzene

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Journal of Environmental Sciences 2024年第4期138卷 153-166页

作者： jia.Wang Yuxi Liu Jiguang Deng Lin Jing Xiuqing Hao Xing zhang Xiaohui Yu Hongxing Dai Beijing Key Laboratory for Green Catalysis and Separation Key Laboratory of Beijing on Regional Air Pollution ControlKey Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaLaboratory of Catalysis Chemistry and NanoscienceDepartment of Chemical EngineeringFaculty of Environment and LifeBeijing University of TechnologyBeijing 100124China

The PdPtVO_(x)/CeO_(2)-ZrO_(2)(PdPtVO_(x)/CZO)catalysts were obtained by using different approaches,and their physical and chemical properties were determined by various *** activities of these materials in the presence of H_(2)O or SO_(2)were evaluated for the oxidation of ethylbenzene(EB).The PdPtVO_(x)/CZO sample exhibited high catalytic activity,good hydrothermal stability,and reversible sulfur dioxide-poisoning performance,over which the specific reaction rate at 160℃,turnover frequency at 160℃(TOF_(Pd or Pt)),and apparent activation energy were 72.6 mmol/(g_(Pt)·sec)or 124.2 mmol/(g_(Pd)·sec),14.2 sec^(-1)(TOF_(Pt))or 13.1 sec^(-1)(TOF_(Pd)),and 58 k J/mol,*** large EB adsorption capacity,good reducibility,and strong acidity contributed to the good catalytic performance of PdPtVO_(x)/*** activity of PdPtVO_(x)/CZO decreased when 50 ppm SO_(2)or(1.0 vol.%H_(2)O+50 ppm SO_(2))was added to the feedstock,but was gradually restored to its initial level after the SO_(2)was cut *** good reversible sulfur dioxide-resistant performance of PdPtVO_(x)/CZO was associated with the facts:(i)the introduction of SO_(2)leads to an increase in surface acidity;(ii)V can adsorb and activate SO_(2),thus accelerating formation of the SO_(x)^(2-)(x=3 or 4)species at the V and CZO sites,weakening the adsorption of sulfur species at the PdPt active sites,and hence protecting the PdPt active sites to be not poisoned by SO_(2).EB oxidation over PdPtVO_(x)/CZO might take place via the route of EB→styrene→phenyl methyl ketone→benzaldehyde→benzoic acid→maleic anhydride→CO_(2)and H_(2)O.

关键词： Ceria-zirconia Supported palladium-platinum-vanadium catalyst Volatile organic compound Ethylbenzene oxidation Sulfur dioxide resistance

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Propagation form of internal cracks induced by continuous casting soft reduction and control strategy for internal quality

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Journal of Iron and Steel Research International 2024年第3期31卷 622-633页

作者： Pu Wang Liang Chen Qun-wei Tang Wei-tao Li Shao-xiang Li jia.quan zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Weifang Special Steel Group Co..Ltd. Weifang 262400ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The propagation form of internal cracks induced by continuous casting soft reduction and the control strategy for enhancing the internal quality of 45 steel through industrial trials and a three-dimensional flow-heat transfer-solidification coupling model were *** results showed that the internal cracks induced by soft reduction exhibited a characteristic of being"coarse in the middle and fine at both ends",and displayed an elliptical arc distribution on the loose side of the strand cross *** cracks originated within the brittle temperature range and propagated inward to the liquid impenetrable temperature and outward to the zero ductility temperature or *** control strategy for enhancing the internal quality of the 45 steel strand through soft reduction is to adjust the casting speed or the reduction zone appropriately,ensuring that the central solid fraction of the reduction zone falls within the range of *** this point,a reasonable reduction amount is allocated to eliminate the center shrinkage cavities and center segregation,even if it results in minor reduction-induced cracks.

关键词： Continuous casting Soft reduction Crack propagation Internal quality Control strategy

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Historical biogeography and evolutionary diversification of Lilium(Liliaceae): New insights from plastome phylogenomics

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Plant Diversity 2024年第2期46卷 219-228页

作者： Nian zh.u Ke Miao Changkun Liu Linbo jia.Jinjin Hu Yongjia.g Huang Yunheng Ji CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China university of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education College of Life SciencesSichuan UniversityChengduSichuan 610065China Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Population Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China

Here, we infer the historical biogeography and evolutionary diversification of the genus Lilium. For this purpose, we used the complete plastomes of 64 currently accepted species in the genus Lilium(14plastomes were newly sequenced) to recover the phylogenetic backbone of the genus and a timecalibrated phylogenetic framework to estimate biogeographical history scenarios and evolutionary diversification rates of Lilium. Our results suggest that ancient climatic changes and geological tectonic activities jointly shaped the distribution range and drove evolutionary radiation of Lilium, including the Middle Miocene Climate Optimum(MMCO), the late Miocene global cooling, as well as the successive uplift of the Qinghai-Tibet Plateau(QTP) and the strengthening of the monsoon climate in East Asia during the late Miocene and the Pliocene. This case study suggests that the unique geological and climatic events in the Neogene of East Asia, in particular the uplift of QTP and the enhancement of monsoonal climate, may have played an essential role in formation of uneven distribution of plant diversity in the Northern Hemisphere.

关键词： Asian monsoon Climatic changes Distribution range Evolutionary complexity Radiative diversification Species diversity Qinghai-Tibet Plateau(QTP)

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