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Distribution and mapping of temperate savanna in the sandy lands of eastern China

Science China Earth Sciences 2025年第1期68卷 128-141页

作者： xiaoya li Feng WANG Tao DUAN Kaijie YANG Bin YANG Chunmei WANG Xin TIAN Qi LU Institute of Ecological Conservation and Restoration Institute of Desertification Studies Chinese Academy of Forestry Institute of Desertification Institute of Desertification Studies Chinese Academy of Forestry Institute of Great Green Wall Satellite Application Centre for Ecology and Environment MEE Institute of Microelectronics Chinese Academy of Sciences Aerospace Information Research Institute Chinese Academy of Sciences Institute of Forest Resource Information Techniques Chinese Academy of Forestry

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution （VHR） unmanned aerial vehicle （UAV） and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover （FWVC） and fractional herbaceous vegetation cover （FHVC） in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error （RMSE） values for the FWVC and FHVC models were 10.69% and 11.67%,and the R2values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10～6 *** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy

关键词： Temperate savanna UAV imagery GF-6 Fractional woody vegetation cover Fractional herbaceous vegetation cover Machine learning

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Synthesis,Characterization of NaA Zeolite from Blast Furnace Slag(BFS)via Alkaline Fusion and Hydrothermal Treatment

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Journal of Wuhan University of Technology(Materials Science) 2023年第2期38卷 401-407页

作者： li Changxin li xiaoya li Chaoyang li li College of Chemical Engineering and Pharmacy Jingchu University of TechnologyJingmen448000China College of Safety Science and Engineering Nanjing Tech UniversityNanjing211816China

A blast furnace slag zeolite(BFSZ)material was successfully synthesized from BFS by alkaline fusion and hydrothermal *** the analyses of XRD,FT-IR,FE-SEM,XRF,CEC and BET surface area measurement,when zeolite was synthesized at a crystallization temperature of 100℃with initial Si/Al ratio of 1:1,the main composition in the product is Na-A *** the above conditions,the BFSZ was synthesized with CEC of 3.06 meq/g and maximum BET surface area of 37.55 m^(2)·g^(-1).Moreover,the incorporating of BFS-derived minor metals(such as Mg,Fe,and Ca)are found to be of little importance for the synthesis of *** the obtained BFSZ material has a great adsorption performance for removing Mn^(2+),Cu^(2+),and NH_(4)^(+)ions diluted in water,owing to the higher CEC.

关键词： blast furnace slag conversion zeolite characterization adsorption

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A COMPREHENSIVE DEA APPROACH FOR THE RESOURCE ALLOCATION PROBLEM BASED ON SCALE ECONOMIES CLASSIFICATION

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Journal of Systems Science & Complexity 2008年第4期21卷 540-557页

作者： xiaoya li Jinchuan CUI Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China.

This paper is concerned with the resource allocation problem based on data envelopment analysis （DEA） which is generally found in practice such as in public services and in production process. In management context, the resource allocation has to achieve the effective-efficient-equality aim and tries to balance the different desires of two management layers： central manager and each sector. In mathematical programming context, to solve the resource allocation asks for introducing many optimization techniques such as multiple-objective programming and goal programming. We construct an algorithm framework by using comprehensive DEA tools including CCR, BCC models, inverse DEA model, the most compromising common weights analysis model, and extra resource allocation algorithm. Returns to scale characteristic is put major place for analyzing DMUs＇ scale economies and used to select DMU candidates before resource allocation. By combining extra resource allocation algorithm with scale economies target, we propose a resource allocation solution, which can achieve the effective-efficient-equality target and also provide information for future resource allocation. Many numerical examples are discussed in this paper, which also verify our work.

关键词： Common weights analysis (CWA) date envelopment analysis (DEA) decision making unit (DMU) efficiency score inverse DEA model multiple-objective linear programming (MOLP) resource allocation problem returns to scale (RTS).

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Effect of drying cracks on swelling and self-healing of bentonite-sand blocks used as engineered barriers for radioactive waste disposal

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1776-1787页

作者： Yu Tan Guangping Zhou Huyuan Zhang xiaoya li Ping liu School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou730000China Key Laboratory of Mechanics on Disaster and Environment in Western China (Lanzhou University) Ministry of EducationLanzhou730000China Civil and Environmental Engineering University of Wisconsin-MadisonWI53706USA

Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste *** groundwater was prepared to represent the geochemistry of Beishan groundwater,and was used to hydrate the blocks during the swelling pressure and swelling strain measurements,as Beishan is the most promising site for China's *** of the surface cracks was recorded by photography,and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried *** results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater,but not affected by the drying *** maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh *** maximum swelling pressure measured in strong(*** ion strength)Beishan groundwater was 44%of the pressure measured in deionized(DI)water,and the maximum swelling strain was reduced to 23%of the strain measured in DI ***,the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks,as demonstrated by the pictures of surface cracks and CT *** hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable(3.7×higher)to the hydraulic conductivity of the fresh block,indicating the self-healing of drying cracks after hydration and swelling in groundwater.A simplified method of protecting the block with plastic wraps before installation is recommended,since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.

关键词： Beishan groundwater chemistry Bentonite buffer Drying cracks High-level radioactive waste(HLW) Self-healing Swelling

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Recent Advances in Interface Modification of Cu/graphite Composites and Layered Ternary Carbides of Modified Layer Candidate

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1061-1072页

作者： WEI Hongming li Mingchao li xiaoya ZHAN Wenyi li Feiyang DAI Yanzhang ZOU Jianpeng State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Guangxi Fangchenggang Nuclear Power Co. Ltd.Fangchenggang 538000China

We review the fundamental properties and significant issues related to Cu/graphite *** particular,recent research on the interfacial modification of Cu/graphite composites is addressed,including the metal-modified layer,carbide-modified layer,and combined modified ***,we propose the use of ternary layered carbide as an interface modification layer for Cu/graphite composites.

关键词： Cu/graphite composites interfacial bonding surface modification wettability layered ternary carbides

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Suppressing the donor-like effect via fast extrusion engineering for high thermoelectric performance of polycrystalline Bi_(2)Te_(2.79)Se_(0.21)

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Journal of Materiomics 2023年第2期9卷 345-352页

作者： Xusheng liu Tong Xing Pengfei Qiu Tingting Deng Peng li Xuewen li xiaoya li Xun Shi State Key Lab of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Key Lab for light-weight Materials Nanjing Tech UniversityNanjing211816China

Bi2Te3-based alloys are the most mature commercial thermoelectric(TE)materials for the cooling application near room ***,the poor mechanical properties of the commercial zone melting(ZM)ingot severely limits the further ***,due to the donor-like effect,the robust polycrystalline n-type bulks usually have low TE performance near room ***,based on the commercial ZM ingots,a high figure of merit(zT)of 1.0 at 320 K and good mechanical properties are achieved via the hot *** dynamic recrystallization in the hot-extrusion process can suppress the donor-like effect and refine the large ZM grains into fine-equiaxed ***,the obtained polycrystalline Bi2Te2.79Se0.21 has good preferential orientation and high carrier mobility(m).The high m and the weaken donor-like effect maintain the high power factor(PF)of 43.1 mW cm^(-1)K^(-2)in the hot-extruded ZM *** to the enhanced phonon scattering,the total thermal conductivity ktot decreased to 1.35 W·m^(-1)·K^(-1).To demonstrate the good mechanical properties of the extruded ZM sample,micro TE dices with the cross sections of 300μm×300 mm and 200μm×200 mm are successfully cut from the extrusion *** study provided a fast and low-cost extrusion technique to improve the TE and mechanical properties of the commercial ZM ingot at room temperature.

关键词： Thermoelectric Bismuth telluride Donor-like effect Hot extrusion

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Positive Periodic Solutions of Second-Order Singular Coupled Systems with Damping Terms

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Journal of Mathematical Research with Applications 2017年第4期37卷 435-448页

作者： Ruipeng CHEN xiaoya li Department of Mathematics North Minzu University

We establish the existence of positive periodic solutions of the second-order singular coupled systems{x′′+ p1（t）x′+ q1（t）x = f1(t, y（t）) + c1（t）,y′′+ p2（t）y′+ q2（t）y = f2(t, x（t）) + c2（t）,where pi, qi, ci ∈ C（R/T Z; R）, i = 1, 2; f1, f2∈ C(R/T Z ×（0, ∞）, R) and may be singular near the zero. The proof relies on Schauder's fixed point theorem and anti-maximum *** main results generalize and improve those available in the literature.

关键词： positive periodic solutions singular coupled systems Schauder’s fixed point theorem weak singularities

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Isorhamnetin protects zearalenone-induced damage via the PI3K/Akt signaling pathway in porcine ovarian granulosa cells

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Animal Nutrition 2022年第4期11卷 381-390页

作者： xiaoya li Huali Chen Zelin Zhang Jiaxin Duan Rongmao Hua Xiaodi li li Yang Jianyong Cheng Qingwang li College of Animal Science and Technology Northwest A&F UniversityYangling712100China School of life Science and Engineering Southwest University of Science and TechnologyMianyang 621000China College of Basic Medicine Hebei University of Chinese MedicineShijiazhuang050000China

Zearalenone(ZEA)is widely derived from moldy cereal grain,which has adverse effects on animal *** particular,pigs are more sensitive to ZEA-induced toxicity than other *** has extensive pharmacological ***,the role of isorhamnetin in ZEA-induced cytotoxicity remains *** study was designed to investigate the therapeutic effect of isorhamnetin on ZEA-induced damage in porcine ovarian granulosa cells and elucidate its molecular *** experiments were conducted,where a minimum of 3 biological replicates were used for each *** Exp.1,ovarian granulosa cells were treated with different concentrations of isorhamnetin(1,5,10,20 and 30μmol/L)and ZEA(0,10,30,60,90 and 120μmol/L)for 24 *** results indicated that 60μmol/L ZEA(half-maximal inhibitory concentration value)and 20μmol/L isorhamnetin(the most effective concentration against ZEA-induced cytotoxicity)were optimum *** Exp.2,ovarian granulosa cells were treated with isorhamnetin(20μmol/L)for 2 h,before treatment with ZEA(60μmol/L)for 24 ***,endoplasmic reticulum stress,oxidative stress,proliferation and hormone secretion of ovarian granulosa cells were *** findings showed that isorhamnetin suppressed(Pling ***,isorhamnetin stimulated(Pliferating cell nuclear antigen(PCNA)and cyclin D,thereby increasing the ratio of S phase cells in respon

关键词： Zearalenone Isorhamnetin Ovarian granulosa cell Apoptosis Endoplasmic reticulum stress Oxidative stress

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Isorhamnetin protects porcine oocytes from zearalenone-induced reproductive toxicity through the PI3K/Akt signaling pathway

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Journal of Animal Science and Biotechnology 2023年第3期14卷 1054-1067页

作者： xiaoya li Jiaxin Duan Shiyou Wang Jianyong Cheng Huali Chen Zelin Zhang li Yang Rongmao Hua Qingwang li College of Animal Science and Technology Northwest A&F UniversityYangling 712100People’s Republic of China College of Animal Science and Technology Shanxi Agricultural UniversityTaigu 030031People’s Republic of China School of life Science and Engineering Southwest University of Science and TechnologyMianyang 621000People’s Republic of China College of Pharmacy Shenzhen Technology UniversityShenzhen 518118People’s Republic of China.

Background Zearalenone(ZEA)widely exists in moldy grains,which seriously destroys the fertility of ***,a natural flavonoid,has extensive of pharmacological ***,the beneficial effect and the underlying molecular mechanism of isorhamnetin involvement in ZEA-induced porcine oocyte damage have not been *** Oocytes were treated with different concentrations of ZEA(3,5,8 and 10μmol/L)and isorhamnetin(5,10,20 and 30μmol/L)for 44 h at 39℃.ZEA(5μmol/L)and isorhamnetin(10μmol/L)were selected for subsequent *** body exclusion rate,apoptosis rate and apoptosis related proteins,ROS levels and SOD2 protein,mitochondrial membrane potential and distribution,endoplasmic reticulum distribution and proteins expression,and PI3K,Akt and p-Akt proteins expression of oocytes were *** addition,the effect of PI3K antagonist(LY294002)on oocyte nuclear maturation and apoptosis were used to determine the involvement of PI3K/Akt signaling *** Our findings showed that ZEA exposure damaged oocytes and isorhamnetin therapy restored the developmental capability of porcine *** promoted polar body extrusion rate to rescue ZEA-induced meiotic arrest in porcine *** alleviated ZEA-induced oxidative stress by stimulating SOD2 protein expression and inhibiting ROS ***,isorhamnetin enhanced normal mitochondrial distribution and mitochondrial membrane potential to prevent mitochondrial dysfunction induced by *** the expression of endoplasmic reticulum stress-related marker proteins(CHOP,GRP78)and the distribution rate of normal endoplasmic reticulum showed that isorhamnetin relieved ZEA-caused endoplasmic reticulum ***,isorhamnetin decreased Bax/Bcl-2 protein expression and inhibited ZEA-induced apoptosis through PI3K/Akt signaling *** Collectively,these results suggest that isorhamnetin protects oocytes from ZEA-caused damage through PI

关键词： Apoptosis Isorhamnetin Oocyte Oxidative stress Porcine Zearalenone

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Measuring urban thermal environment from accessibility-based perspective:A case study in a populous city

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Geography and Sustainability 2024年第3期5卷 329-342页

作者： Xinyu Dong xiaoya li Yanmei Ye Dan Su Runjia Yang Angela Lausch Department of Land Management Zhejiang UniversityHangzhou 310058China Department of Computational Landscape Ecology Helmholtz Centre for Environmental Research-UFZLeipzig 04318Germany Landscape Ecology Lab Geography DepartmentHumboldt-Universität zu BerlinBerlin 10099Germany Department of Physical Geography and Geoecology Martin Luther University Halle-WittenbergHalle 06120Germany Department of Architecture Facility Management and GeoinformationAnhalt University of Applied SciencesDessau 06846Germany

Understanding the spatial interaction among residents,cooling service,and heat risk area in complex urban areas is conducive to developing targeted ***,traditional urban thermal environment assessments typically relied on simple linear integration of associated indicators,often neglecting the spatial interaction *** explore the spatial interaction among the three elements,this study proposes an accessibility-based urban thermal environment assessment *** Zhengzhou,a rapidly urbanizing city,as an example,remotely sensed images from three periods(2010,2015 and 2020)were applied to extract urban green space(UGS)and hot island area(HIA).An improved two-step floating catchment area(2SFCA)method and bivariate local Moran’s I were employed to explore whether residents’clustering locations are more likely to access cooling service or to be exposed to heat *** results demonstrate that the UGS in the city has been expanding,whereas the HIA shrank within the inner city in 2015 and then increased in *** though the urban thermal environment may have improved in the last decade,the spatial interaction among the residents,cooling service and heat risk area could be *** autocorrelation shows an increase in locations that are disadvantageous for resident *** when sufficient cooling services were provided,residents in these areas could still be exposed to high heat *** developed urban thermal environment framework provides a novel insight into the residents’heat risk exposure and cooling service accessibility,and the findings could assist urban planners in targeting the improvement of extra heat exposure risk locations.

关键词： Urban heat island Urban green space Accessibility Remote sensing Spatial autocorrelation analysis

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