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Impact of climate change on wheat yield and quality in the Yellow River Basin under RCP8.5 during 2020–2050

Advances in Climate Change Research 2022年第3期13卷 397-407页

作者： Xiao-Xu LONG Hui ju Jian-Dong WANG shi-Hong GONG Guang-Yong li Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agriculture SciencesBeijing 100081China College of Water Resources&Civil Engineering China Agricultural UniversityBeijing 100083China Department of Irrigation and Drainage China Institute of Water Resources and Hydropower ResearchBeijing 100048China

Studying the impact of future climate change on the yield and quality of wheat in the Yellow River Basin(YRB)is both essential for rationalizing the utilization of climate resources and ensuring national food *** this study,we employed corrected refined meteorological grid data(30 km×30 km)generated by the Climate-Weather Research and Forecasting model under RCP8.5,coupled with the DSSAT-CERES-Wheat model to predict the impact of climate change on wheat phenology,yield,and grain nitrogen content(GNC)in the YRB from 2020 to *** to the type of wheat variety and planting management in the YRB,we designed five wheat ecological regions(I-V).The results show that from 2020 to 2050,the agro-meteorological resource,involving temperature,solar radiation,and precipitation,would have an overall increasing trend during the wheat growth seasons in the *** growth period of wheat was generally shortened by approximately 8 d,including 6 d less from sowing to anthesis,and 2 d less from anthesis to *** general,the predicted wheat yield showed a decreasing trend in the YRB,with an average reduction of 0.19%over the period from 2020 to 2050 compared with the baseline period from 1975 to 2005,and the spatial variation in wheat yield change was considerably *** the future,the Qing‒Zang Spring Wheat region(V)in the western part of the YRB would be the only region with a yield increase of 35.4%,whereas the Northern Spring Wheat region(I)in the northern part of the YRB would be the region exhibiting the greatest decrease of 9.9%.Moreover,compared with the baseline,the GNC would increase by an average of 2.3%in the YRB,with a significant increase in the southern and central parts during *** GNC increase in the Huang‒Huai Winter Wheat region(III)was the highest with a 12.5%increment,but the Qing‒Zang Spring Wheat region(V)is the only region where GNC would decline,with an average decrease of 18.9%.This study implies that wheat yield and GNC have a

关键词： Yellow river basin Climate change Wheat Yield Grain nitrogen content

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Novel robust S transform based on the clipping method

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Journal of Systems Engineering and Electronics 2013年第2期24卷 209-214页

作者： Xiumei li Yingtuo ju School of Information Science and Engineering Hangzhou Normal University Rohde & Schwarz Asia Pte Ltd No.10 Changi Business Park Central 2Singapore

This paper presents a novel robust S transform algorithm based on the clipping method to process signals corrupted by impulsive *** proposed algorithm is introduced to determine the clipping threshold value according to the characteristics of the signal *** in various impulsive noise models are considered to illustrate that the robust S transform can achieve better performance than the standard S ***,mean square errors for instantaneous frequency estimation of the robust S transform are compared with that of the standard S transform,showing that the robust S transform can achieve significantly improved instantaneous frequency estimation for the signals in impulsive noise.

关键词： S transform clipping method impulsive noise mean square error(MSE)

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Piezoelectricity in two-dimensional group-Ill monochalcogenides

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Nano Research 2015年第12期8卷 3796-3802页

作者： Wenbin li ju li Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Nuclear Science and Engineering Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA

It is found that several layer-phase group-III monochalcogenides, including GaS, GaSe, and InSe, are piezoelectric in their monolayer form. First-principles calculations reveal that the piezoelectric coefficients of monolayer GaS, GaSe, and InSe （2.06, 2.30, and 1.46 pm-V-1） are of the same order of magnitude as previously discovered two-dimensional （2D） piezoelectric materials such as boron nitride （BN） and MoS2 monolayers. This study therefore indicates that a strong piezoelectric response can be obtained in a wide range of two-dimensional materials with broken inversion symmetry. The co-existence of piezoelectricity and superior photo-sensitivity in these monochalcogenide monolayer semiconductors means they have the potential to allow for the integration of electromechanical and optical sensors on the same material platform.

关键词： piezoelectricity two-dimensional(2D) material monochalcogenide density functional theory(DFT)calculation

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Effect of Ti content on microstructure and properties of TixZrVNb refractory high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2020年第10期27卷 1318-1325页

作者： Tian-dang Huang shi-yu Wu Hui Jiang Yi-ping Lu Tong-min Wang Ting-ju li Key Laboratory of Solidification Control and Digital Preparation Technology(liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116024China College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao 266590China

This study aimed to investigate the microstructure and mechanical properties of TixZrVNb(x=1,1.5,2)refractory high-entropy alloys at room and elevated *** TiZrVNb alloy consisted of the body-centered cubic(bcc)matrix with a small amount of V2Zr *** Ti1.5ZrVNb and Ti2ZrVNb alloys exhibited a single-phase bcc *** room temperature,the tensile ductility of the as-cast alloys increased from 3.5%to 12.3%with the increase in the Ti *** TixZrVNb alloys exhibited high yield strength at 600°C,and the ultimate yield strength was more than 900 *** occurred at 800°C,but the ultimate yield strength could still exceed 200 ***,the TixZrVNb alloys displayed low densities but high specific yield strengths(SYSs).The lowest density of TixZrVNb alloys was only 6.12 g/cm^3,but the SYS could reach about 180 MPa·cm^3·g^−1,which is better than those of most reported high-entropy alloys(HEAs).

关键词： high-entropy alloys mechanical properties low density elevated temperature

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Photocatalytic vinyl radical-mediated multicomponent 1,4-/1,8-carboimination across alkynes and olefins/(hetero)arenes

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Science China Chemistry 2024年第2期67卷 558-567页

作者： Shan-Shan li Yu-shi Jiang Xue-ling Luo Xuming Ran Yuqiang li Dong Wu Cheng-Xue Pan Peng-ju Xia School of Chemistry and Pharmaceutical Sciences Guangxi Normal UniversityGuilin541004China Shanghai Artificial Intelligence Laboratory Shanghai200433China The Institute for Advanced Studies Wuhan UniversityWuhan430064China

We developed a highly selective and efficient multicomponent transformation by utilizing alkynes and olefins/(hetero)arenes through photoinduced energy-transfer *** reaction involves the formation of three distinct chemical bonds,namely C(sp~3)–C(sp~2),C(sp~2)–C(sp~3),and C(sp~3)–N,in a single coordinated *** strategy used a vinyl radical-mediated radical relay approach under mild conditions,exhibiting a broad substrate scope(>70 examples),excellent functional-group tolerance,and remarkable regio-and *** the utilization of a combination of experimental techniques and density functional theory(DFT),we delved deeper into the mechanistic intricacies of this distinctive *** revealed that the selective radical addition to electron-deficient alkynes,rather than olefins,was governed by the inherent reactivity of alkyl *** discovery presented a highly effective approach for the synthesis of stereodefined multisubstituted alkenes.

关键词： alkyne-olefin coupling DFT studies regio-and anti-stereoselectivity multisubstituted alkenes

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Synthesis and Design of Distillation Columns for Wide-Boiling Binary Mixtures with Vapor Recompression Heat Pumps

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China Petroleum Processing & Petrochemical Technology 2023年第4期25卷 127-138页

作者： shi li SINOPEC Research Institute of Petroleum Processing Co. LtdBeijing 100083China

The vapor recompression heat pump(VRHP) distillation technology offers significant improvements in energy efficiency for distillation systems with small temperature differences between the top and bottom of the column. However, the separation of wide-boiling binary mixtures leads to substantial temperature differences between the top and bottom of the column. This limits the applicability of conventional VRHP due to high capital costs and strict performance requirements of the compressor. To overcome these challenges and to accommodate compressor operating conditions, a novel synthesis and design method is introduced to integrate VRHPs with wide-boiling binary mixture distillation columns(WBMDCs). This method enables quick determination of an initial configuration for the integrated WBMDC-VRHP system and helps identify the optimum configuration with the minimum total annual cost. Two examples, namely the separation of benzene/toluene and isopropanol/chlorobenzene, are employed to derive optimum configurations of the WBMDC-VRHP and compare them with the WBMDC. A systematic comparison between the WBMDC-VRHP and WBMDC demonstrates the superior steady-state performance and economic efficiency of the WBMDC-VRHP.

关键词： vapor recompression heat pump wide-boiling binary mixtures distillation column energy saving synthesis and design

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Assessment of habitat suitability of the snow leopard (Panthera uncia) in Qomolangma National Nature Reserve based on MaxEnt modeling

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Zoological Research 2018年第6期39卷 373-386页

作者： De-Feng Bai Peng-ju Chen Luciano Atzeni Lhaba Cering Qian li Kun shi Wildfife Institute School of Nature Conservation Beiiing Forestry University Beijing 100083 China Everest Snow Leopard Conservation Center Rikaze Xizang 857000 China Qomolangma National Nature Reserve Administration Rikaze Xizang 857000 China Eco-Bridge Continental Beijing 100085 China

Habitat evaluation constitutes an important and fundamental step in the management of wildlife populations and conservation policy planning. Geographic information system （GIS） and species presence data provide the means by which such evaluation can be done. Maximum Entropy （MaxEnt） is widely used in habitat suitability modeling due to its power of accuracy and additional descriptive properties To survey snow leopard populations in Qomolangma （Mt. Everest） National Nature Reserve （QNNR）, Xizang （Tibet）, China, we pooled 127 pugmarks, 415 scrape marks, and 127 non-invasive identifications of the animal along line transects and recorded 87 occurrences through camera traps from 2014-2017. We adopted the MaxEnt model to generate a map highlighting the extent of suitable snow leopard habitat in QNNR. Results showed that the accuracy of the MaxEnt model was excellent （mean AUC=0.921）. Precipitation in the driest quarter, ruggedness, elevation, maximum temperature of the warmest month, and annual mean temperature were the main environmental factors influencing habitat suitability for snow leopards, with contribution rates of 20.0%, 14.4%, 13.3%, 8.7%, and 8.2% respectively The suitable habitat area extended for 7 001.93 km^2, representing 22.72% of the whole reserve. The regions bordering Nepal were the main suitable snow leopard habitats and consisted of three separate habitat patches Our findings revealed that precipitation, temperature conditions, ruggedness, and elevations of around 4 000 m a.s.I, influenced snow leopard preferences at the landscape level in QNNR. We advocate further research and cooperation with Nepal to evaluate habitat connectivity and to explore possible proxies of population isolation among these patches. Furthermore, evaluation of subdivisions within the protection zones of QNNR is necessary to improve conservation strategies and enhance protection.

关键词： Qomolangma National Nature Reserve Snow leopard MaxEnt Habitat suitability assessment Tibet

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混凝土中多点聚集爆炸效应起爆参数优化设计

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爆炸与冲击 2025年第1期45卷 151-165页

作者：时本军李杰徐小辉徐天涵郭纬李孝臣李超李干陆军工程大学爆炸冲击防灾减灾全国重点实验室江苏南京210007

混凝土介质中多点同时或彼此微差爆炸可产生复杂的地冲击波叠加聚集效应,从而使特定作用区域内的地冲击波压力显著增强,大大提升爆炸的毁伤威力。为获取多点爆源不同排布方式下爆炸聚集效应及地冲击传播衰减规律,进行了混凝土中单点和... 详细信息

混凝土介质中多点同时或彼此微差爆炸可产生复杂的地冲击波叠加聚集效应,从而使特定作用区域内的地冲击波压力显著增强,大大提升爆炸的毁伤威力。为获取多点爆源不同排布方式下爆炸聚集效应及地冲击传播衰减规律,进行了混凝土中单点和七点聚集爆炸的现场和数值模拟试验,基于正交设计方法和灰色系统理论对多点起爆参数进行了优化设计,建立了比例装药间距、比例有源装药高度和比例起爆微差等因素与不同爆心距下峰值压力间的灰色关联度系数及灰色关联度,确定了起爆参数的优选组合,并开展了数值模拟试验检验。分析结果表明:影响地冲击聚集效应的主要因素为比例装药间距,其次为比例起爆微差,最次为比例有源装药高度。在本模拟试验情况下,采用优化的起爆参数时,即在比例装药间距为0.549 m/kg^(1/3)、比例起爆微差为0.239 m/kg^(1/3)和比例有源装药高度为0 m/kg^(1/3)时,地冲击波聚集效应达到最佳,最大可达单点同等装药量产生的地冲击压力的4.7倍。

关键词：灰色理论聚集爆炸混凝土关联度优化设计

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Influence of the mechanical properties of materials on the ultimate pressure-bearing capability of a pressure-preserving controller

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Petroleum Science 2024年第5期21卷 3558-3574页

作者： Xiao-jun shi He-Ping Xie Cong li Gui-Kang liu Zi-Jie Wei Tian-Yu Wang ju li Qiu-Yue li State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065SichuanChina Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060GuangdongChina College of Mechanical Engineering Sichuan UniversityChengdu610065SichuanChina Jinshi Drilltech Co.Ltd. Tangshan063004HebeiChina

The pressure-preserving controller is the core part of deep in-situ pressure-preserving coring(IPP-Coring) system, and its pressure-preserving capability is the key to IPP-Coring technology. To achieve a good understanding of the influence of mechanical properties of materials on the ultimate pressure-bearing capability(UPB-Capability) of the pressure-preserving controller, the IPP-Coring experimental platform was developed to test the UPB-Capability of pressure-preserving controllers of four different materials. The experimental results show that the UPB-Capability of pressure-preserving controllers with different material varies greatly. A numerical model of the pressure-preserving controller was developed to study the influences of mechanical parameters of materials on the UPB-Capability of the pressurepreserving controller after the accuracy of the numerical model is verified by experiments. The results indicate that the yield strength(YS) and Poisson's ratio(PR) of the material have little effect on the UPB-Capability of the pressure-preserving controller, whereas the elastic modulus(EM) of the material has a significant effect. A generalized model of the UPB-Capability of the pressure-preserving controller is developed to reveal the mechanism of the influence of material properties on the UPB-Capability of the pressure-preserving controllers. Considering these results, the future optimization direction of the pressure-preserving controller and material selection scheme in practical engineering applications of the pressure-preserving controller are suggested.

关键词： In-situ pressure-preserving coring Pressure-preserving controller Material properties Ultimate pressure-bearing capability

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Protective Graphite Coating for Two-Dimensional Carbon/Carbon Composites

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Fluid Dynamics & Materials Processing 2024年第1期20卷 97-108页

作者： Wei shi Zhengyi li Xiaobing Xu Yingshui Yu Xiaofei Ding Heng ju School of Mechanical and Power Engineering Dalian Ocean UniversityDalian116023China School of Mechanical and Electrical Engineering Gongqing Institute of Science and TechnologyJiujiang332020China

Two-dimensional carbon/carbon(2D C/C)composites are a special class of carbon/carbon composites,generally obtained by combining resin-impregnated carbon fiber clothes,which are then cured and *** study deals with the preparation of a protective coating for these *** coating,based on graphite,was prepared by the slurry *** effect of graphite and phenolic resin powders with different weight ratios was *** results have shown that the coating slurry can fill the pores and cracks of the composite surface,thereby densifying the surface layer of the *** the increase of the graphite powder/phenolic resin weight ratio,the coating density is enhanced while the coating surface flatness decreases;moreover,the protective ability of coating against erosion first increases(from 1:3 to 2:2)and then decreases(from 2:2 to 3:1).When the weight ratio is about 1:1,the coating for 2D C/C composites exhibits the best erosion resistance,which greatly aids these materials during gas *** this case,the erosion rate is decreased by approximately 41.5%at the impact angle of 30°and 52.3%at normal impact,*** can be attributed to the ability of the coating slurry to infiltrate into the substrate,thereby bonding the fibers together and increasing the compactness of the 2D C/C composites.

关键词： Carbon/carbon composites graphite coating microstructure erosion resistance

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