检索结果-南通市图书馆

Impacts of information about cOVID-19 on pig farmers'production willingness and behavior:Evidence from china

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 Integrative Agriculture 2024年第4期23卷 1429-1441页

作者： Huan c.en lei Mao Yuehua Zhang School of Public Affairs Zhejiang UniversityHangzhou 310058China School of Insurance Central University of Finance and EconomicsBeijing 100081China Innovation center of Yangtze River Delta Zhejiang UniversityJiaxing 314100China

This paper examines the impacts of information about cOVID-19 on pig farmers'production willingness by using endorsement experiments and follow-up surveys conducted in 2020 and 2021 in *** results show that,first,farmers were less willing to scale up production when they received information about *** information in 2020 that the second wave of cOVID-19 might occur without a vaccine reduced farmers'willingness to scale up by 13.4%,while the information in 2021 that cOVID-19 might continue to spread despite the introduction of vaccine reduced farmers'willingness by 4.4%.Second,farmers whose production was affected by cOVID-19 were considerably less willing to scale up,given the access to cOVID-19 ***,farmers'production willingness can predict their actual production behavior.

关键词： cOVID-19 randomized experiment information treatment production willingness

Suffic.ent conditions for Amalgamated 3-Manifolds to be ∂-Irreducible

在线全文

学校读者我要写书评

暂无评论

chinese Annals of Mathematics,Series B 2024年第2期45卷 161-172页

作者： Bing FANG Fengchun lei Liang LIANG School of Mathematical Sc.ences Dalian University of TechnologyDalian 116024LiaoningChina School of Mathematics Liaoning Normal UniversityDalian 116029LiaoningChina

In this paper,the authors give some suffic.ent conditions for an amalgamated 3-manifold along a compact connected surface F with boundary to be ∂-irreducible in terms of distances between some kinds of vertex subsets ... 详细信息

关键词： ∂-Irreducibility Irreducibility Amalgamated 3-manifold curve complex Arc complex

engineering the future cereal crops with big biological data:toward intelligence-driven breeding by design

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2024年第8期51卷 781-789页

作者： lei Liu Jimin Zhan Jianbing Yan National Key Laboratory of crop Genetic Improvement Hubei Hongshan LaboratoryHuazhong Agricultural UniversityWuhanHubei 430070China

How to feed 10 billion human populations is one of the challenges that need to be addressed in the following decades,especially under an unpredicted climate *** breeding,initiating from the phenotype-based selection by local farmers and developing into current biotechnology-based breeding,has played a critical role in securing the global food ***,regarding the changing environment and ever-increasing human population,can we breed outstanding crop varieties fast enough to achieve high productivity,good quality,and widespread adaptability?This review outlines the recent achievements in understanding cereal crop breeding,including the current knowledge about crop agronomic traits,newly developed techniques,crop big biological data research,and the possibility of integrating them for intelligence-driven breeding by design,which ushers in a new era of crop breeding practice and shapes the novel architecture of future *** review focuses on the major cereal crops,including rice,maize,and wheat,to explain how intelligence-driven breeding by design is becoming a reality.

关键词： crop Big biological data Multi-omic Artificial intelligence crop design breeding

coseismic coulomb stress changes induced by a 2020-2021 M_(W)>7.0 Alaska earthquake sequence in and around the Shumagin gap and its influence on the Alaska-Aleutian subduction interface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2024年第1期15卷 1-12页

作者： lei Yang Jianjun Wang caijun Xu School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China collaborative Innovation center of Geospatial Technology Wuhan 430079China Key Laboratory of Geospace environment and Geodesy Ministry of EducationWuhan UniversityWuhan 430079China

Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 chignik thrust earthquake on July 29,*** spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among *** we examine the coseismic coulomb stress change imparted by the three earthquakes and their influence on the subduction *** results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and chignik earthquakes,with the coulomb stress changes of 3.95 bars and 2.89 bars,*** coulomb stress change caused by the Sand Point earthquake at the hypocenter of the chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%*** factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic coulomb stress changes at the subduction interface nearby these mainshocks,with an average coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.

关键词： The 2020-2021 Alaska earthquake sequence coseismic coulomb stress change Mainshock-aftershock triggering The Alaska-Aleutian subduction interface The Shumagin gap

environmental dynamics of nitrogen and phosphorus release from river sediments of arid areas

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2024年第5期16卷 685-698页

作者： SU Wenhao WU c.engc.eng Sun Xuanxuan lei Rongrong lei Li WANG Ling ZHU Xinping college of Biosc.ence and Resources environment Beijing University of AgricultureBeijing 102206China Xinjiang Tianxi environmental Protection Technology co.Ltd. Urumqi 830000China college of Resources and environment Sc.ences Xinjiang Agricultural UniversityUrumqi 830052China

Human activities lead to the accumulation of a large amount of nitrogen and phosphorus in sediments in ***,nitrogen and phosphorus can be affected by environment and re-enter the upper water body,causing secondary pollution of the river *** this study,laboratory simulation experiments were conducted initially to investigate the release of nitrogen and phosphorus from river sediments in Urumqi city and the surrounding areas in Xinjiang Uygur Autonomous Region of china and determine the factors that influence their *** results of this study showed significant short-term differences in nitrogen and phosphorus release characteristics from sediments at different sampling *** proposed secondary kinetics model(i.e.,pseudo-second-order kinetics model)better fitted the release process of sediment nitrogen and *** release of nitrogen and phosphorus from sediments is a complex process driven by multiple factors,therefore,we tested the influence of three factors(pH,temperature,and disturbance intensity)on the release of nitrogen and phosphorus from sediments in this *** most amount of nitrate nitrogen(NO_(3)^(–)-N)was released under neutral conditions,while the most significant release of ammonia nitrogen(NH_(4)^(+)-N)occurred under acidic and alkaline *** release of nitrite nitrogen(NO_(2)^(-)-N)was less affected by *** dissolved total phosphorus(DTP)released significantly in the alkaline water environment,while the release of dissolved organic phosphorus(DOP)was more significant in acidic *** release amount of soluble reactive phosphorus(SRP)increased with an increase in *** sediments released nitrogen and phosphorus at higher temperatures,particularly NH_(4)^(+)-N,NO_(3)^(–)-N,and *** highest amount of DOP was released at 15.0℃.An increase in disturbance intensity exacerbated the release of nitrogen and phosphorus from ***_(4)^(+)-N,DTP,and SRP levels increased linearly with the intens

关键词： sediment nitrogen and phosphorus environmental dynamics pseudo-second-order kinetics model dissolved organic phosphorus(DOP) Urumqi city

Effects of acid deposition control in china:a review based on responses of subtropical forests

在线全文

学校读者我要写书评

暂无评论

Frontiers of environmental Sc.ence & engineering 2024年第6期18卷 115-126页

作者： Danni Xie Xiaodong Ge lei Duan Jan Mulder School of Land engineering Chang’an UniversityXi’an 710064China State Key Laboratory of environmental Simulation and Pollution control School of EnvironmentTsinghua UniversityBeijing 100084China State environmental Protection Key Laboratory of Sources and control of Air Pollution complex Beijing 100084China Faculty of environmental Sc.ences and Natural Resource Management Norwegian University of Life SciencesBox 5003NO-1432ÅsNorway

For many decades,acid deposition used to pose a significant regional air pollution challenge in *** substantial emission control of anthropogenically derived sulfur and nitrogen containing gasses,both sulfur and nitrogen deposition,as well as the acid rain-affected area,have significantly decreased compared to their peak ***,particularly in the humid subtropics,are sensitive to acid deposition,as evidenced by soil acidification,sulfate and nitrate leaching in stream water,and elevated soil nitrous oxide *** in the total deposition of sulfur and nitrogen,caused a significant decline in sulfate and nitrate leaching from subtropical forest and subsequently in sulfate and nitrate concentrations in stream water,although there was about a 5-year *** delay may be attributed to the desorption of accumulated sulfate and continued elevated mineralization of accumulated nitrogen *** of nitrous oxide,a potent greenhouse gas,also declined in nitrogen-saturated subtropical forest soils,as soil water nitrate concentration ***,subtropical forests in china suffering from elevated acid deposition have begun to ***,the current levels of sulfur and nitrogen deposition continue to exceed the critical loads,i.e.,the assigned threshold levels in accordance with emission control policies,in more than 10%of the country’s land area,respectively,indicating remaining risks of acidification and ***,further emission reductions are urgently needed,also because they will help achieving goals related to air quality and nitrous oxide emissions.

关键词： Acidification critical load Nitrous oxide Surface water chemistry Recovery

Effects of Number of Bleed Holes on Shock-Wave/Boundary-Layer Interactions in a Transonic compressor Stator

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 Thermal Sc.ence 2024年第2期33卷 611-624页

作者： LI Bai ZHOU Xun LUO lei DU Wei School of energy Sc.ence and engineering Harbin Institute of TechnologyHarbin150001China

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous *** bleed holes are arranged on the suction surface in a single row,two staggered rows and three staggered *** each bleed scheme,five bleed pressure ratios are examined at an inlet Mach number of *** results indicate that the aerodynamic performance of the cascade is significantly improved by the porous *** the single-row scheme,the maximum reduction in total pressure losses is 57%.For the two-staggered-row and three-staggered-row schemes,there is an optimal bleed pressure ratio of 1.0,and the maximum reductions in total pressure loss are 68% and 75%,*** low loss in the cascade is due to the well-controlled boundary *** new local supersonic region created by the bleed hole is the key reason for the improved boundary *** vortex induced by side bleeding provides another mechanism for delaying flow *** the bleed holes could create multiple local supersonic regions,which reduce the range of the adverse pressure gradient that the boundary layer needs to *** is the reason why cascades with more bleed holes perform better.

关键词： transonic compressor stator shock wave/boundary layer interaction porous bleed number of bleed holes

Reduction of unactivated alkyl chlorides enabled by light-induced single electron transfer

在线全文

学校读者我要写书评

暂无评论

Sc.ence china chemistry 2024年第2期67卷 471-481页

作者： lei Dai Zhao-Fei Zhang Xiang-Yu c.en School of chemical Sc.ences University of the Chinese Academy of SciencesBeijing100049China Institute of chemistry Chinese Academy of SciencesBeijing100190China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou256606China

Alkyl chlorides are abundant and easily accessible starting ***,due to the high reduction potentials associated with unactivated alkyl chlorides,achieving their single electron reduction remains a persistent *** challenge has spurred the exploration of effic.ent activation methods to overcome this *** recent years,photocatalysis has emerged as a mild and potent tool for the single electron reduction of unactivated alkyl chlorides,opening up new possibilities in this *** the rapid advancements in this area,a comprehensive review that provides a conceptual understanding of this emerging field,with a specific focus on reaction design and catalytic mechanisms,would be timely and highly ***,we present an overview of various synthetic techniques for photoinduced single electron reduction of unactivated alkyl ***,we also discuss the limitations of the present methods and future directions that lie ahead in this field.

关键词： photocatalysis unactivated alkyl chlorides single electron transfer radical reactions

Optimization-based mode selection scheme for OAM millimeter wave system in the off-axis misalignment case

在线全文

学校读者我要写书评

暂无评论

Digital communications and Networks 2024年第1期10卷 101-108页

作者： Haie Dou lei Wang Bin Kang Baoyu Zheng Key Lab of Broadband Wireless communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing210003China School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210003China

Millimeter-wave transmission combined with Orbital Angular Momentum(OAM)has the advantage of reducing the loss of beam power and increasing the system ***,to fulfill this advantage,the antennas at the transmitter and receiver must be parallel and coaxial;otherwise,the accuracy of mode detection at the receiver can be seriously *** this paper,we design an OAM millimeter-wave communication system for overcoming the above ***,the first contribution is that the power distribution between different OAM modes and the capacity of the system with different mode sets are analytically derived for performance *** second contribution lies in that a novel mode selection scheme is proposed to reduce the total interference between different *** results show that system performance is less affected by the offset when the mode set with smaller modes or larger intervals is selected.

关键词： Orbital angular momentum Millimeter wave Off-axis misalignment Mode selection capacity