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Effects of drip and flood irrigation on carbon dioxide exchange and crop growth in the maize ecosystem in the Hetao Irrigation District,China

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Journal of Arid Land 2024年第2期16卷 282-297页

作者： LI Chaoqun HAN Wenting PENG Manman College of Mechanical and Electrical Engineering Heze UniversityHeze 274015China College of Mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100China Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China

Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,*** research delves into the effects of these irrigation methods on carbon dioxide(CO_(2))exchange and crop growth in this *** experimental site was divided into drip and flood irrigation *** irrigation schedules of this study aligned with the local commonly used irrigation *** employed a developed chamber system to measure the diurnal CO_(2)exchange of maize plants during various growth stages under both drip and flood irrigation *** May to September in 2020 and 2021,two sets of repeated experiments were *** each experiment,a total of nine measurements of CO_(2)exchange were performed to obtain carbon exchange data at different growth stages of maize *** each CO_(2)exchange measurement event,CO_(2)flux data were collected every two hours over a day-long period to capture the diurnal variations in CO_(2)*** each CO_(2)exchange measurement event,the biological parameters(aboveground biomass and crop growth rate)of maize and environmental parameters(including air humidity,air temperature,precipitation,soil water content,and photosynthetically active radiation)were *** results indicated a V-shaped trend in net ecosystem CO_(2)exchange in daytime,reducing slowly at night,while the net assimilation rate(net primary productivity)exhibited a contrasting ***,compared with flood irrigation,drip irrigation demonstrated significantly higher average daily soil CO_(2)emission and greater average daily CO_(2)absorption by maize ***,within the maize ecosystem,drip irrigation appeared more conducive to absorbing atmospheric CO_(2).Furthermore,drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation.A strong linear relationship existed between leaf area index and light utiliza

关键词： carbon dioxide exchange maize growth drip irrigation harvest index net primary productivity Hetao Irrigation District

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FDSC-YOLOv8:Advancements in Automated Crack Identification for Enhanced Safety in Underground Engineering

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 3035-3049页

作者： Rui Wang Zhihui Liu Hongdi Liu Baozhong Su Chuanyi Ma key Laboratory of Computing Power Network and Information Security Ministry of EducationShandong Computer Science Center(National Supercomputer Center in Jinan)Qilu University of Technology(Shandong Academy of Sciences)Jinan250353China School of Qilu Transportation Shandong UniversityJinan250100China Geotechnical and Structural Engineering Center Shandong UniversityJinan250061China shandong Lairong High-Speed Railway Co. Ltd.Weihai264200China shandong High-Speed Group Co. Ltd.Jinan250014China

In underground engineering,the detection of structural cracks on tunnel surfaces stands as a pivotal task in ensuring the health and reliability of tunnel ***,the dim and dusty environment inherent to under-ground engineering poses considerable challenges to crack *** paper proposes a crack segmentation algorithm termed as Focused Detection for Subsurface Cracks YOLOv8(FDSC-YOLOv8)specifically designed for underground engineering structural ***,to improve the extraction of multi-layer convolutional features,the fixed convolutional module is replaced with a deformable convolutional ***,the model’s receptive field is enhanced by introducing a multi-branch convolutional module,improving the extraction of shallow features for small ***,the Dynamic Snake Convolution module is incorporated to enhance the extraction capability for slender and weak ***,the Convolutional Block Attention Module(CBAM)module is employed to achieve better target *** FDSC-YOLOv8s algorithm’s mAP50 and mAP50-95 reach 96.5%and 66.4%,according to the testing data.

关键词： Crack segmentation improved YOLOv8 engineering applications feature extraction

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Intelligent Fault Diagnosis Method of Rolling Bearings Based on Transfer Residual Swin Transformer with Shifted Windows

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Structural Durability & Health Monitoring 2024年第2期18卷 91-110页

作者： Haomiao Wang Jinxi Wang Qingmei Sui Faye Zhang Yibin Li Mingshun Jiang Phanasindh Paitekul The Institute of Marine Science and Technology Shandong UniversityQingdao26623China The School of Control Sciences and Engineering Shandong UniversityJinan250061China Thailand Institute of Scientific and Technological research Amphoe Khlong LuangPathum Thani12120Thailand

Due to their robust learning and expression ability for complex features,the deep learning(DL)model plays a vital role in bearing fault ***,since there are fewer labeled samples in fault diagnosis,the depth of DL models in fault diagnosis is generally shallower than that of DL models in other fields,which limits the diagnostic *** solve this problem,a novel transfer residual Swin Transformer(RST)is proposed for rolling bearings in this *** has 24 residual self-attention layers,which use the hierarchical design and the shifted window-based residual *** with transfer learning techniques,the transfer RST model uses pre-trained parameters from ImageNet.A new end-to-end method for fault diagnosis based on deep transfer RST is ***,wavelet transform transforms the vibration signal into a wavelet time-frequency *** signal’s time-frequency domain representation can be represented ***,the wavelet time-frequency diagram is the input of the RST model to obtain the fault ***,our method is verified on public and self-built *** results show the superior performance of our method by comparing it with a shallow neural network.

关键词： Rolling bearing fault diagnosis transformer self-attention mechanism

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Linear Quadratic Optimal Control for Systems Governed by First-Order Hyperbolic Partial Differential Equations

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Journal of Systems Science & Complexity 2024年第1期37卷 230-252页

作者： XUE Xiaomin XU Juanjuan ZHANG Huanshui School of Control Science and Engineering Shandong UniversityJinan 250061China College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266000China

This paper focuses on linear-quadratic(LQ)optimal control for a class of systems governed by first-order hyperbolic partial differential equations(PDEs).Different from most of the previous works,an approach of discretization-then-continuousization is proposed in this paper to cope with the infinite-dimensional nature of PDE *** contributions of this paper consist of the following aspects:(1)The differential Riccati equations and the solvability condition of the LQ optimal control problems are obtained via the discretization-then-continuousization method.(2)A numerical calculation way of the differential Riccati equations and a practical design way of the optimal controller are ***,the relationship between the optimal costate and the optimal state is established by solving a set of forward and backward partial difference equations(FBPDEs).(3)The correctness of the method used in this paper is verified by a complementary continuous method and the comparative analysis with the existing operator results is *** is shown that the proposed results not only contain the classic results of the standard LQ control problem of systems governed by ordinary differential equations as a special case,but also support the existing operator results and give a more convenient form of computation.

关键词： Discretization-then-continuousization method first-order hyperbolic partial differential equations forward and backward partial difference equations linear quadratic optimal control.

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The nature of electron density enhancement over a wide altitude range during ionosphere heating experiments at EISCAT

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Earth and Planetary Physics 2024年第2期8卷 408-414页

作者： Jun Wu Jian Wu Jie Feng QingLiang Li ShuJi Hao ZhengWen Xu HaiSheng Zhao YaBin Zhang National key Laboratory of Electromagnetic Environment China Research Institute of Radio Wave PropagationBeijing 102206China School of Physics Xidian UniversityXi’an 710071China

During the course of ionospheric heating experiments, researchers at the European Incoherent Scatter Scientific Association (EISCAT) observed an apparent electron density enhancement. The enhancement extended over a wide range of altitudes, above the reflection altitude of the high-frequency pump wave. However, whether this enhancement actually corresponds to a true enhancement in electron density remains an open question. When the dispersion relation of ion acoustic waves is followed, the frequency ratio of the enhanced ion line to the background ion line suggests that the profile of the effective ion mass may have remained unchanged. Furthermore, the solar radio flux and ion drift velocity indicate no significant changes in the ion species and their densities. In conclusion, the electron density enhancement observed at EISCAT should not, in fact, be considered a true enhancement.

关键词： incoherent scatter radar(ISR) ionospheric heating electron density ion acoustic wave

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Long-term ocean temperature trend and marine heatwaves

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Journal of Oceanology and Limnology 2024年第4期42卷 1037-1047页

作者： Min ZHANG Yangyan CHENG Gang WANG Qi SHU Chang ZHAO Yuanling ZHANG Fangli QIAO First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China key Laboratory of Marine Sciences and Numerical Modelling Ministry of Natural ResourcesQingdao 266061China shandong key Laboratory of Marine Science and Numerical Modeling Qingdao 266061China

Marine heatwaves(MHWs)can cause irreversible damage to marine ecosystems and *** MHW characterization remains difficult,because the choice of a sea surface temperature(SST)temporal baseline strongly influences MHW *** a recent work suggesting that there should be a communicating baseline for long-term ocean temperature trends(LTT)and MHWs,we provided an effective and quantitative solution to calculate LTT and MHWs simultaneously by using the ensemble empirical mode decomposition(EEMD)*** long-term nonlinear trend of SST obtained by EEMD shows superiority over the traditional linear trend in that the data extension does not alter prior *** MHWs identified from the detrended SST data exhibited low sensitivity to the baseline choice,demonstrating the robustness of our *** also derived the total heat exposure(THE)by combining LTT and *** THE was sensitive to the fixed-period baseline choice,with a response to increasing SST that depended on the onset time of a perpetual MHW state(identified MHW days equal to the year length).Subtropical areas,the Indian Ocean,and part of the Southern Ocean were most sensitive to the long-term global warming trend.

关键词： marine heatwaves(MHWs) ensemble empirical mode decomposition(EEMD) long-term temperature(LTT)trend total heat exposure(THE)

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Drilling-based measuring method for the c-φ parameter of rock and its field application

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International Journal of Mining Science and Technology 2024年第1期34卷 65-76页

作者： Bei Jiang Fenglin Ma Qi Wang Hongke Gao Dahu Zhai Yusong Deng Chuanjie Xu Liangdi Yao State key Laboratory for Tunnel Engineering China University of Mining and Technology-BeijingBeijing 100083China State key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China research Center of Geotechnical and Structural Engineering Shandong UniversityJinan 250061China

The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters.

关键词： Digital drilling Rock crushing zone c-u parameter Measurement method Field application

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Efficiency-first spraying mission arrangement optimization with multiple UAVs in heterogeneous farmland with varying pesticide requirements

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Information Processing in Agriculture 2024年第2期11卷 237-248页

作者： Yang Li Yanqiang Wu Xinyu Xue Xuemei Liu Yang Xu Xinghua Liu Nanjing Institute of Agricultural Mechanization Ministry of Agriculture and Rural AffairsNanjing 210014PR China College of Mechanical&Electronic Engineering Shandong Agricultural UniversityTai'an 271018PR China key Laboratory of Modern Agricultural Equipment Ministry of Agriculture and Rural AffairsNanjing 210014PR China shandong Provincial key Laboratory of Horticultural Machinery and Equipment Tai’an 271018PR China shandong Provincial Engineering Laboratory of Agricultural Equipment Intellectualization Tai’an 271018PR China

Combining multiple crop protection Unmanned Aerial Vehicles(UAVs)as a team for a scheduled spraying mission over farmland now is a common way to significantly increase ***,given some issues such as different configurations,irregular borders,and especially varying pesticide requirements,it is more important and more complex than other multi-Agent Systems(MASs)in common *** this work,we focus on the mission arrangement of UAVs,which is the foundation of other high-level cooperations,systematically propose Efficiency-first Spraying Mission Arrangement Problem(ESMAP),and try to construct a united problem framework for the mission arrangement of crop protection ***,to characterise the differences in sub-areas,the varying pesticide requirement per unit is well considered based on Normalized Difference Vegetation Index(NDVI).Firstly,the mathematical model of multiple crop-protection UAVs is established and ESMAP is ***,an acquisition method of a farmland’s NDVI map is proposed,and the calculation method of pesticide volume based on NDVI is ***,an improved Genetic Algorithm(GA)is proposed to solve ESMAP,and a comparable combination algorithm is *** simulations for algorithm analysis are carried out within MATLAB,and it is determined that the proposed GA is more efficient and accurate than the ***,a mission arrangement tested with three UAVs was carried out to validate the effectiveness of the proposed GA in spraying *** results illustrated that it performed well,which took only 90.6%of the operation time taken by the combination algorithm.

关键词： Efficiency-first optimization Mission arrangement Multi-UAVs Heterogeneous farmland

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Non-Fully Conjugated Photovoltaic Materials with Y-Series Acceptor Backbone for High-Performance Organic Solar Cells

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Chinese Journal of Chemistry 2024年第11期42卷 1307-1318页

作者： Hairui Bai Qunping Fan Ruijie Ma Xia Guo Wei Ma Maojie Zhang State key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’anShaanxi710049 China National Engineering research Center for Colloidal Materials School of Chemistry&Chemical EngineeringShandong UniversityJinanShandong250100 China Department of Electronic and Information Engineering Research Institute for Smart Energy(RISE)The Hong Kong Polytechnic UniversityKowloon999077 Hong KongChina

In the last few years,organic solar cells(OSCs)have made significant progress in photovoltaic performance,mainly due to the innovative development of active layer materials,especially Y-series and related derivatives as acceptors which have become the key factor that boosts the power conversion ***,to achieve high-performance OSCs,an emerging molecular design strategy of applying flexible alkyl units as linkers to construct non-fully conjugated acceptors has been developed and addressed great *** review highlights the non-fully conjugated photovoltaic materials with Y-series backbone that enable high-performance *** OSCs have been achieved by some representative non-fully conjugated material *** related molecular design strategies are discussed in ***,a brief summary and future prospect are provided in advancing the non-fully conjugated photovoltaic materials with Y-series backbone towards the brighter future.

关键词： Organic solar cells All-polymer solar cells Non-fully conjugated photovoltaic materials Power conversion efficiency Polymer acceptors Organicel ectronics

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Evolution Mechanism of a Severe Squall Line Triggered by the Coupling of a Sea Breeze Front and a Gust Front

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Journal of Tropical Meteorology 2024年第2期30卷 200-210页

作者：万夫敬孙敏庞华基赵海军赵传湖 Qingdao Meteorological Bureau QingdaoShandong 266003 China Shanghai Central Meteorological Observatory Shanghai 200030 China Linyi Meteorological Bureau LinyiShandong 276037 China Frontier Science Center for Deep Ocean Multispheres and Earth System(FDOMES)and Physical Oceanography Laboratory Ocean University of ChinaQingdaoShandong 266101 China

In the present study, a severe squall line(SL) was analyzed by using intensive observational surface data and radar monitoring products. In this process, mesoscale convergence lines, such as the sea breeze front(SBF), gust front and dry line, served as the main triggering and strengthening factors. The transition from convection triggering to the formation of the initial shape was mainly affected by the convergence line of the SBF, which combined with thermal convection to form the main parts of the SL. In the later stage, the convergence line of the gust front merged with other convergence lines to form a series of strong convective cells. The SBF had good indicative significance in terms of severe convective weather warnings. The suitable conditions of heat, water vapor and vertical wind shear on the shandong Peninsula were beneficial to the maintenance of the SL. Before SL occurrence, tropopause folding strengthened, which consequently enhanced the baroclinic property in the middle and upper troposphere. The high sensible heat flux at the surface easily produced a positive potential vorticity anomaly in the low layer, resulting in convective instability, which was conducive to the maintenance of these processes. In the system, when precipitation particles passed through the unsaturated air layer, they underwent strong evaporation, melting or sublimation, and the cooling effect formed negative buoyancy, which accelerated the sinking of the air and promoted the sustained development of the surface gale. Together with the development of lowlevel mesocyclones, the air pressure decreased rapidly, which was conducive to gale initiation.

关键词： squall line sea breeze front gust front cold pool thunderstorm gale

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