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Effects of wind speed,underlying surface,and seed morphological traits on the secondary seed dispersal in the Tengger Desert,China

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Journal of Arid Land 2024年第4期16卷 531-549页

作者： QU Wenjie ZHAO Wenzhi yang xinguo WANG Lei ZHANG Xue QU Jianjun Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education Ningxia UniversityYinchuan 750021China University of Chinese Academy of Sciences Beijing 100049China School of Ecology and Environment Ningxia UniversityYinchuan 750021China

The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key role.Based on field wind tunnel experiments using 11 common plant species on the southeastern edge of the Tengger Desert,China,we studied the secondary seed dispersal in the fixed and semi-fixed sand dunes as well as in the mobile dunes in order to understand the limitations of vegetation regeneration and the maintenance of its stability.Our results indicated that there were significant variations among the selected 11 plant species in the threshold of wind speed(TWS).The TWS of Caragana korshinskii was the highest among the 11 plant species,whereas that of Echinops gmelinii was the lowest.Seed morphological traits and underlying surface could generally explain the TWS.During the secondary seed dispersal processes,the proportions of seeds that did not disperse(no dispersal)and only dispersed over short distance(short-distance dispersal within the wind tunnel test section)were significantly higher than those of seeds that were buried(including lost seeds)and dispersed over long distance(long-distance dispersal beyond the wind tunnel test section).Compared with other habitats,the mobile dunes were the most difficult places for secondary seed dispersal.Buried seeds were the easiest to be found in the semi-fixed sand dunes,whereas fixed sand dunes were the best sites for seeds that dispersed over long distance.The results of linear mixed models showed that after controlling the dispersal distance,smaller and rounder seeds dispersed farther.Shape index and wind speed were the two significant influencing factors on the burial of seeds.The explanatory power of wind speed,underlying surface,and seed morphological traits on the seeds that did not disperse and dispersed over short distance was far greater than that on the seeds that were buried and dispersed over long distance,implying that the processes and mechanisms of burial and long-distance dispersal are more complex.In summar

关键词： seed dispersal seed morphological traits wind speed vegetation regeneration wind tunnel Tengger Desert

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Spatiotemporal characteristics of seed rain and soil seed bank of artificial Caragana korshinskii Kom. forest in the Tengger Desert, China

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Journal of Arid Land 2024年第4期16卷 550-566页

作者： SHEN Jianxiang WANG Xin WANG Lei WANG Jiahui QU Wenjie ZHANG Xue CHANG Xuanxuan yang xinguo CHEN Lin QIN Weichun ZHANG Bo NIU Jinshuai College of Ecological Environment Ningxia UniversityYinchuan 750021China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwest China Ministry of EducationNingxia UniversityYinchuan 750021China College of Agriculture Ningxia UniversityYinchuan 750021China

Vegetation restoration and reconstruction are effective approaches to desertification control and achieving social and economic sustainability in desert areas.However,the self-succession ability of native plants during the later periods of vegetation restoration remains unclear.Therefore,this study was conducted to bridge the knowledge gap by investigating the regeneration dynamics of artificial forest under natural conditions.The information of seed rain and soil seed bank was collected and quantified from an artificial Caragana korshinskii Kom.forest in the Tengger Desert,China.The germination tests were conducted in a laboratory setting.The analysis of species quantity and diversity in seed rain and soil seed bank was conducted to assess the impact of different durations of sand fixation(60,40,and 20 a)on the progress of vegetation restoration and ecological conditions in artificial C.korshinskii forest.The results showed that the top three dominant plant species in seed rain were Echinops gmelinii Turcz.,Eragrostis minor Host.,and Agropyron mongolicum Keng.,and the top three dominant plant species in soil seed bank were E.minor,Chloris virgata Sw.,and E.gmelinii.As restoration period increased,the density of seed rain and soil seed bank increased first and then decreased.While for species richness,as restoration period increased,it gradually increased in seed rain but decreased in soil seed bank.There was a positive correlation between seed rain density and soil seed bank density among all the three restoration periods.The species similarity between seed rain or soil seed bank and aboveground vegetation decreased with the extension of restoration period.The shape of the seeds,specifically those with external appendages such as spines and crown hair,clearly had an effect on their dispersal,then resulting in lower seed density in soil seed bank.In addition,precipitation was a crucial factor in promoting rapid germination,also resulting in lower seed density in soil seed bank.Our findings provide valuable insigh

关键词： ecological restoration soil seed bank seed rain artificial forest vegetation desertification Caragana korshinskii Tengger Desert

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Antagonism effect of residual S triggers the dual-path mechanism for water oxidation

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Journal of Energy Chemistry 2024年第6期93卷 568-579,I0014页

作者： Li Liu Jinming Cao Siqi Hu Tinghui Liu Can Xu Wensheng Fu xinguo Ma Xiaohui yang Chongqing Key Laboratory of Green Catalytic Materials and Technology College of ChemistryChongqing Normal UniversityChongqing 401331China School of Science Hubei University of TechnologyWuhan 430068HubeiChina Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China

Transition metal chalcogenides(TMCs)are recognized as pre-catalysts,and their(oxy)hydroxides derived from electrochemical reconstruction are the active species in the water oxidation.However,understanding the role of the residual chalcogen in the reconstructed layer is lacking in detail,and the corresponding catalytic mechanism remains controversial.Here,taking Cu_(1-x)Co_(x)S as a platform,we explore the regulating effect and existence form of the residual S doped into the reconstructive layer for oxygen evolution reaction(OER),where a dual-path OER mechanism is proposed.First-principles calculations and operando~(18)O isotopic labeling experiments jointly reveal that the residual S in the reconstructive layer of Cu_(1-x)Co_(x)S can wisely balance the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM)by activating lattice oxygen and optimizing the adsorption/desorption behaviors at metal active sites,rather than change the reaction mechanism from AEM to LOM.Following such a dual-path OER mechanism,Cu_(0.4)Co_(0.6)S-derived Cu_(0.4)Co_(0.6)OSH not only overcomes the restriction of linear scaling relationship in AEM,but also avoids the structural collapse caused by lattice oxygen migration in LOM,so as to greatly reduce the OER potential and improved stability.

关键词： Electrochemical reconstruction Adsorbate evolution mechanism Lattice oxygen oxidation mechanism Oxygen evolution reaction Residual sulfur

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Dynamic behavior analysis, color image encryption and circuit implementation of a novel complex memristive system

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Optoelectronics Letters 2024年第3期20卷 183-192页

作者： XIONG Li WANG Xuan ZHANG xinguo HE Tongdi School of Physics and Electromechanical Engineering Hexi UniversityZhangye 734000China School of Information Science and Engineering Dalian Polytechnic UniversityDalian 116034China School of Information Science and Engineering Lanzhou UniversityLanzhou 730000China

This paper is devoted to introduce a novel four-dimensional memristor-involved system and its applications in image encryption and chaotic circuit. The typical dynamical behaviors of the memristor-involved system are explored, such as chaotic phase potraits, Lyapunov exponent spectrum(LES), bifurcation diagram(BD) and complexity analysis. Then a color image encryption algorithm is designed. In this algorithm, the sequences generated by the four-dimensional memristor-involved system are used in scrambling and diffusion algorithm for three channels.

关键词： image system chaotic

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Biocrust-induced partitioning of soil water between grass and shrub in a desert steppe of Northwest China

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Journal of Arid Land 2023年第1期15卷 63-76页

作者： yang xinguo WANG Entian QU Wenjie WANG Lei Northwest National Key Laboratory Breeding Base for Land Degradation and Ecological Restoration Ningxia UniversityYinchuan 750021China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems Ministry of EducationNingxia UniversityYinchuan 750021China Ecology and Environment College Ningxia UniversityYinchuan 750021China

Maintaining the stability of exotic sand-binding shrub has become a large challenge in arid and semi-arid grassland ecosystems in northern China.We investigated two kinds of shrublands with different BSCs(biological soil crusts)cover in desert steppe in Northwest China to characterize the water sources of shrub(Caragana intermedia Kuang et H.C.Fu)and grass(Artemisia scoparia Waldst.et Kit.)by stable 18O isotopic.Our results showed that both shrublands were subject to persistent soil water deficiency from 2012 to 2017,the minimum soil depth with CV(coefficient of variation)<15% and SWC(soil water content)<6% was 1.4 m in shrubland with open areas lacking obvious BSC cover,and 0.8 m in shrubland covered by mature BSCs.For C.intermedia,a considerable proportion of water sources pointed to the surface soil.Water from BSCs contributed to averages 22.9%and 17.6%of the total for C.intermedia and A.scoparia,respectively.C.intermedia might use more water from BSCs in rainy season than dry season,in contrast to A.scoparia.The relationship between shrub(or grass)and soil water by δ^(18)O shown significant differences in months,which partly verified the potential trends and relations covered by the high variability of the water source at seasonal scale.More fine roots at 0-5 cm soil layer could be found in the surface soil layer covered by BSCs(8000 cm/m^(3))than without BSCs(3200 cm/m^(3)),which ensured the possibility of using the surface soil water by C.intermedia.The result implies that even under serious soil water deficiency,C.intermedia can use the surface soil water,leading to the coexistence between C.intermedia and A.scoparia.Different with the result from BSCs in desert areas,the natural withdrawal of artificial C.intermedia from desert steppe will be a long-term process,and the highly competitive relationship between shrubs and grasses also determines that its habitat will be maintained in serious drought state for a long time.

关键词： desert steppe biological soil crusts water resource Caragana intermedia Artemisia scoparia

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Viscoelastic stress change from the 1931 MW7.8 Fuyun earthquake and its impacts on seismic activity around the Altai mountains

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Geodesy and Geodynamics 2024年第4期15卷 326-337+430页

作者： Yali Shao Jiankun He xinguo Wang Youjia Zhao Key Laboratory of Tibetan Plateau Earth System Environment and Resources Institute of Tibetan Plateau Research Chinese Academy of Sciences University of Chinese Academy of Sciences

The 1931 MW7.8 Fuyun earthquake occurred around the Altai mountains, an intracontinental deformation belt with limited active strain-rate accumulation. To explore whether seismic activity in this deformation belt was affected by stress interaction among different active faults, we calculate the Coulomb failure stress change（ΔCFS） induced by the Fuyun earthquake due to coseismic deformation of the elastic crust and postseismic viscoelastic relaxation of the lower crust and upper mantle. Numerical results show that the total ΔCFS at a 10-km depth produced by the Fuyun earthquake attains approximately 0.015-0.134 bar near the epicenter, and just before the occurrence of the 2003 MW7.2 Chuya earthquake, which distances about 400 km away from the Fuyun earthquake. Among the increased ΔCFS,viscoelastic relaxation from 1931 to 2003 contributes to approximately 0.014-0.131 bar, accounting for>90% of the total ΔCFS. More importantly, we find that for the recorded seismicity in the region with a radius of about 270 km to the Fuyun earthquake from 1970 to 2018, the percentage of earthquakes that fall in positive lobes of ΔCFS resolved on the NNW-SSE Fuyun strike-slip fault, on the NWW-SEE Irtysh strike-slip fault, and on the NW-SE Kurti reverse fault is up to 67.22%-91.36%. Therefore, the predictedΔCFS suggests that the impact of the 1931 MW7.8 Fuyun earthquake on seismic activity around the Altai mountains is still significant as to hasten occurrence of the 2003 MW7.2 Chuya earthquake at a relatively far distance and to trigger its aftershocks in the near-field even after several decades of the mainshock.

关键词： Altai mountains Fuyun earthquake Coulomb failure stress change Viscoelastic relaxation Seismic activity

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Recess-free enhancement-mode AlGaN/GaN RF HEMTs on Si substrate

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Journal of Semiconductors 2024年第6期45卷 81-86页

作者： Tiantian Luan Sen Huang Guanjun Jing Jie Fan Haibo Yin xinguo Gao Sheng Zhang Ke Wei Yankui Li Qimeng Jiang Xinhua Wang Bin Hou Ling yang Xiaohua Ma Xinyu Liu High-Frequency High-Voltage Device and Integrated Circuits R&D Center Institute of Microelectronics of Chinese Academy of SciencesBe i-jing 100029China School of integrated Circuits University of Chinese Academy of SciencesBeijing 100049China Faculty of integrated Circuits Xidian UniversityXi’an 710071China

Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron gas(2DEG)channel.The fabricated E-mode HEMTs exhibit a relatively high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact.

关键词： AlGaN/GaN heterostructure ultrathin-barrier enhancement-mode radio-frequency power added efficiency silicon substrate

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Predicting structure-dependent Hubbard U parameters via machine learning

Materials Futures

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Materials Futures 2024年第2期3卷 161-169页

作者： Guanghui Cai Zhendong Cao Fankai Xie Huaxian Jia Wei Liu Yaxian Wang Feng Liu xinguo Ren Sheng Meng Miao Liu Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190People’s Republic of China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190People’s Republic of China Songshan Lake Materials Laboratory DongguanGuangdong 523808People’s Republic of China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Tencent AI Lab TencentShenzhen 518057People’s Republic of China Department of Materials Science and Engineering University of UtahSalt Lake CityUT 84112United States of America

DFT+U is a widely used treatment in the density functional theory(DFT)to deal with correlated materials that contain open-shell elements,whereby the quantitative and sometimes even qualitative failures of local and semi-local approximations can be corrected without much computational overhead.However,finding appropriate U parameters for a given system and structure is non-trivial and computationally intensive,because the U value has generally a strong chemical and structural dependence.In this work,we address this issue by building a machine learning(ML)model that enables the prediction of material-and structure-specific U values at nearly no computational cost.Using Mn–O system as an example,the ML model is trained by calibrating DFT+U electronic structures with the hybrid functional results of more than 3000 structures.The model allows us to determine an accurate U value(MAE=0.128 eV,R^(2)=0.97)for any given Mn–O structure.Further analysis reveals that M–O bond lengths are key local structural properties in determining the U value.This approach of the ML U model is universally applicable,to significantly expand and solidify the use of the DFT+U method.

关键词： DFT+U machine learning Bayesian optimization

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Grazing exclusion-induced shifts,the relative importance of environmental filtering,biotic interactions and dispersal limitation in shaping desert steppe communities,northern China

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Journal of Arid Land 2018年第3期10卷 402-415页

作者： WANG Xing SONG Naiping yang xinguo WANG Lei CHEN Lin Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China Ningxia University School of Agriculture Ningxia University

Grazing exclusion is one of the most efficient approaches to restore degraded grassland but may negatively affects the recovery of species diversity. Changes in plant species diversity should be a consequence of the ecological assembly process. Local community assembly is influenced by environmental filtering, biotic interactions, and dispersal. However, how these factors potentially contribute to changes to species diversity is poorly understood, especially in harsh environments. In this study, two management sites within a Stipa breviflora desert steppe community（typical natural steppe） were selected in northern China. In one of the two management sites, grazing has been excluded since 2010 and in the other with open grazing by sheep. In August 2016, three plots were established and 100 sampling units were created within each plot in a 5 m×5 m area at the two management sites. To assess the effects of grazing exclusion on S. breviflora steppe, we analyzed the vegetation biomass, species diversity,soil organic carbon, and soil particle size distribution using paired T-tests. In addition, variation partitioning was applied to determine the relative importance of environmental filtering and dispersal limitation. Null mode analysis was used to quantify the influence of biotic interactions in conjunction with Eco Sim niche overlap and co-occurrence values. Our results demonstrated that（1） species diversity significantly decreased and the main improvements in soil quality occurred in the topsoil 0–10 cm after the grazing exclusion;（2） environmental filtering was important for community assembly between grazed and fenced grassland and this appears particularly true for soil particle size distribution, which may be well correlated with soil hydrological processes; and（3） however, competitive exclusion may play a significant role within the exclusion. The multiple pathways of assembly may collectively determine negative effects on the restoration of species diversity. Therefore, designers should be aware of the risk of

关键词： community assembly environmental filtering Stipa breviflora desert steppe semi-arid grassland

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马一浮“以中摄西”文化视域下的中华文化发展观

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浙江学刊 2024年第2期 233-238页

作者：袁新国浙江省社会科学院杭州310025

马一浮对西方文化和中国传统文化的认识前后都有转变,开始企慕西方文化,质疑中国传统文化,后又质疑西方文化,推崇中国传统文化。他虽极力推崇中国传统文化,但并没有完全排斥西方文化,在对西方文化从企慕追逐到理性扬弃的转变过程中形成... 详细信息

马一浮对西方文化和中国传统文化的认识前后都有转变,开始企慕西方文化,质疑中国传统文化,后又质疑西方文化,推崇中国传统文化。他虽极力推崇中国传统文化,但并没有完全排斥西方文化,在对西方文化从企慕追逐到理性扬弃的转变过程中形成了“以中摄西”的世界主义文化观。这种文化观突破“中体西用”“西体中用”之思维,提出中西古今同“体”之思想,为当今中华文化的发展提供了思考方向,即超越中西古今“体用”思维,注重学习和培养的中华文化发展观。

关键词：马一浮体用思维以中摄西中华文化发展观

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