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Journal of Materials Science & Technology 2022年第33期128卷 22-30页

作者： Weizong Bao Jie Chen Guoqiang Xie School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

A superiority in interfacial bonding is favorable to fabricate high-strength conductive composites for electrical contact *** the present work,high strength and high conductivity multi-scale metallic glass composites(including micron-scale Cu Zr Al metallic glass reinforcement,hundred-nanometer-scale Cu Cr Zr crystalline grain matrix,and nano-scale precipitated phase)were fabricated by a one-step spark plasma sintering(SPS).The strength and conductivity of the bulk copper matrix metallic glass composites(BCMGCs)were enhanced simultaneously with the increase in the sintering pressure of the *** excellent performance is attributed to the improved interfacial bonding between the metallic glass reinforcement and the copper alloy matrix due to the high pressure assisted by temperature and pulsed *** particular,the precipitation of nanoprecipitates at the interface further reduces the interfacial resistance and improves the mechanical properties of the *** work broadens the horizon for the selection and optimization of reinforcements and manufacturing processes for high-performance electrical contact materials(ECMs).

关键词： CuZrAl metallic glass Spark plasma sintering Mechanical properties Electrical performance

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Research on the Causes and Coping Strategies of the Land Subsidence Caused by the Tunnel Construction Projects

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International Journal of Technology Management 2015年第11期 26-28页

作者： chena Kana Sichuan College of Architectural Technology DeyangSichuan 618000 China

In this paper, we conduct research on the causes and coping strategies of the land subsidence caused by the tunnel construction projects. We analyze the issues from the following of the perspectives. （1） Analysis method. To solve large scale system of the development of computer hardware and the numerical calculation method, we use the basic analysis to deal with it. （2） The empirical of methods. Ground motion is usually leads to the basic development of the inclined tunnel surface vertical displacement, the result of the movement process can turn to a settling tank. （3） Machine learning based approaches. In one of biggest difficulties when using neural network method is to obtain all possible parameters related to ground subsidence, we use the machine learning model to handle the challenge. In the final part, we show prospect for the future research, we will combine more numerical analysis tools to optimize the current methodology.

关键词： Land Subsidence Tunnel Construction Causes and Coping Strategies Modelling.

Examining effective use of data sources and modeling algorithms for improving biomass estimation in a moist tropical forest of the Brazilian Amazon

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International Journal of Digital Earth 2017年第10期10卷 996-1016页

作者： Yunyun Feng Dengsheng Lu Qi chena Michael Keller Emilio Moran Maiza Nara dos-Santos Edson Luis Bolfe Mateus Batistella The Nurturing Station for the State Key Laboratory of Subtropical Silviculture Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration of Zhejiang ProvinceSchool of Environmental&Resource SciencesZhejiang Agriculture and Forestry UniversityLin AnPeople’s Republic of China Center for Global Change and Earth Observations Michigan State UniversityEast LansingMIUSA Department of Geography University of Hawaii at ManoaHonoluluHIUSA Brazilian Agricultural Research Corporation–Embrapa Informática Agropecuária CampinasBrazil USDA Forest Service International Institute of Tropical ForestryRio PiedrasPRUSA Brazilian Agricultural Research Corporation–Embrapa Secretariat of Intelligence and Macro StrategyBrasíliaBrazil Brazilian Agricultural Research Corporation(Embrapa) BrasíliaBrazil

Previous research has explored the potential to integrate lidar and optical data in aboveground biomass(AGB)estimation,but how different data sources,vegetation types,and modeling algorithms influence AGB estimation is poorly *** research conducts a comparative analysis of different data sources and modeling approaches in improving AGB ***-based spectral responses and textures,lidar-derived metrics,and their combination were used to develop AGB estimation *** results indicated that(1)overall,RapidEye data are not suitable for AGB estimation,but when AGB falls within 50–150 Mg/ha,support vector regression based on stratification of vegetation types provided good AGB estimation;(2)Lidar data provided stable and better estimations than RapidEye data;and stratification of vegetation types cannot improve estimation;(3)The combination of lidar and RapidEye data cannot provide better performance than lidar data alone;(4)AGB ranges affect the selection of the best AGB models,and a combination of different estimation results from the best model for each AGB range can improve AGB estimation;(5)This research implies that an optimal procedure for AGB estimation for a specific study exists,depending on the careful selection of data sources,modeling algorithms,forest types,and AGB ranges.

关键词： Lidar RapidEye aboveground biomass moist tropical forest support vector regression random forest linear regression stratification

Erosion-control mechanism of sediment check dams on the Loess Plateau

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International Journal of Sediment Research 2021年第5期36卷 668-677页

作者： zhaoyin Wang Zuyu chena Shu Yu Qiang Zhang Yu Wang Jianwei Hao State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research

Severe soil erosion occurs on the Loess Plateau in China, which makes the Yellow River the most sediment-laden river in the world. Construction of about 60,000 sediment check dams has remarkably controlled soil erosion on the Loess Plateau and reduced the sediment load of the middle and lower Yellow River. Nonetheless, little is known about the mechanism of erosion control and vegetation development of sediment check dams. The function of a single check dam mainly is trapping sediment,while the function of a train of check dams comprising dozens of or over hundreds of check dams in a gully encompasses controlling bed incision and reducing erosion energy. A formula was proposed to calculate the potential energy of bank failure and slope failure in a gully, which essentially constitutes the erosion energy. The erosion energy increases when gully incision occurs, which is induced by the incision of the Yellow River and its tributaries on the Loess Plateau. Sediment deposition in many gullies due to construction of check dams reduces the erosion energy to almost zero, which in turn greatly reduces soil erosion and sediment yield. Construction of check dams promotes vegetation development. The vegetation-erosion dynamics model was used to study the effect of check dams on vegetation development. Simulation results show that reforestation without check dam construction might result in an increase of vegetation cover in the first ten years and then a drop of vegetation cover to less than 10% in the later years. The check dams provide a foundation for vegetation development.

关键词： Loess plateau Check dam Energy of soil erosion Vegetation-erosion dynamics Gully incision

An iterative data-driven turbulence modeling framework based on Reynolds stress representation

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Theoretical & Applied Mechanics Letters 2022年第5期12卷 371-387页

作者： Yuhui Yin Zhi Shen Yufei Zhang Haixin chena Song Fu School of Aerospace Engineering Tsinghua UniversityBeijing 100084China China Academy of Launch Vehicle Technology Beijing 100076China

Data-driven turbulence modeling studies have reached such a stage that the basic framework is settled,but several essential issues remain that strongly affect the *** problems are studied in the current research:(1)the processing of the Reynolds stress tensor and(2)the coupling method between the machine learning model and flow *** the Reynolds stress processing issue,we perform the theoretical derivation to extend the relevant tensor arguments of Reynolds ***,the tensor representation theorem is employed to give the complete irreducible invariants and integrity *** adaptive regularization term is employed to enhance the representation *** the coupling issue,an iterative coupling framework with consistent convergence is proposed and then applied to a canonical separated *** results have high consistency with the direct numerical simulation true values,which proves the validity of the current approach.

关键词： Turbulence modeling Reynolds-averaged Navier-Stokes equations Reynolds stress representation Machine learning

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Acetone Formation from Photolysis of 2-Propanol on Anatase-TiO2（101）

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Chinese Journal of Chemical Physics 2017年第1期30卷 1-6,I0001页

作者： Zhen-hua Genga b Xiao chena a. State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics Dalian 115023 China b. University of Chinese Academy of Sciences BeLiinE 100049 China

Photocatalysis of 2-propanol on A-TiO2（101） has been investigated using a temperature programed desorption method with 266 nm laser light. A clear mechanism is proposed for photodissociation of 2-propanol on A-TiO2（101）. Acetone product on five coordinate Ti4＋ sites is formed in a stepwise manner in which the O-H dissociation proceeds first and then followed by secondary C-H dissociation of 2-propanol while H atoms are transferred to the adjacent bridge bond oxygen （BBO） sites. Low temperature water is formed in a thermally driven process via H-atom on BBO in exchange with isopropyl groups of molecule 2-propanol, while isopropyl radical desorbs at high temperature during the TPD process. The observation demonstrates the prospect of TiO2 as a photocatalyst for degradation of organics.

关键词： 2-Propanol Photochemistry A-TiO2(101) Temperature-programmed desorption

Function-Oriented Natural Product Synthesis

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Chinese Journal of Chemistry 2021年第4期39卷 838-854页

作者： Kaiqi Chen Fan Wu Xiaoguang Lei Beijing National Laboratory for Molecular Sciences State Key Laboratory of Natural and Biomimetic DrugsKey Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationDepartment of Chemical BiologyCollege of Chemistry and Molecular EngineeringSynthetic and Functional Biomolecules CenterPeking UniversityBeijing100871 China Peking-Tsinghua Center for Life Science Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijing100871 China

Natural products and their derivatives have long been used as medicinal agents,and they still make up a significant fraction of clinically approved *** product synthesis provides a rich and unparalleled opportunity to develop new synthetic transformations,conceive novel and general strategies to access complex structures,and study the mechanism of action of bioactive *** combination of the tools and principles of chemistry,together with the tools of modern biology,allows us to create complex synthetic and natural molecules,comprising processes with novel biological,chemical and physical *** account will illustrate the opportunities that lie at this interface between synthetic organic chemistry and chemical biology by describing a series of examples that we are actively working on in our laboratory at Peking *** take the inspiration from mother nature to develop new synthetic strategies to achieve the efficient synthesis of complex natural *** addition,we also conduct chemical biology studies for these bioactive natural products to elucidate their cellular targets and mode of ***,we further use bioactive natural products to explore new biology and develop novel drug candidates for human diseases,such as cancers and infectious diseases.

关键词： Natural products Total synthesis Chemical biology Target identification Drug discovery

Amorphous molybdenum sulfide mediated EDTA with multiple active sites to boost heavy metal ions removal

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Chinese Chemical Letters 2021年第9期32卷 2797-2802页

作者： Qi Huang Yizhong Zhang Wei Zhou Xiang Huang Yiliang chena Xin Tan Tao Yu School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China School of Environmental Science and Engineering Tianjin UniversityTianjin 300350China School of Science Tibet UniversityLhasa 850000China School of Science Tianjin UniversityTianjin 300350China Research Center of Environmental Pollution Control Engineering Technology Chinese Research Academy of Environmental SciencesBeijing 100012China

The rational design of strong affinity adsorbents for heavy metal ions removal remains a critical challenge for water *** this study,amorphous molybdenum sulfide composites(EDTA-MoSx(x=2,3))were fabricated via a facile hydrothermal method mediated by EDTA,which was applied to heavy metal ions(Cu^(2+),Cd^(2+),Pb^(2+),Zn^(2+)and Ni^(2+))removal from aqueous solutions.A case study for Cu^(2+)ions showed that the adsorption capacity of EDTA-MoSx(x=2,3)was superior to crystalline phase MoS2 at pH 6.0 with an initial concentration of 200 mg/*** mechanisms of different sulfide groups and—COOH of EDTA-MoSx(x=2,3)were verified systematically via a series of experiments,characterizations,and density functional theory(DFT)*** bridging S_(2)^(2-)and—COOH covalently bonded with Cu^(2+)ions were ascribed to the critical factors for this enhanced removal efficiency on the surface of EDTA-MoSx(x=2,3).This work offers a new method to enhance the adsorption performance of molybdenum sulfide-based materials by controlling crystallinity mediated with an organic complex small molecule.

关键词： Amorphous phase MoS_(2) MoS_(3) Adsorption Heavy metal ions DFT calculations

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Restless legs syndrome in a hospital sample of Chinese adults:prevalence,sleep quality,fatigue degree,daytime sleepiness and literature review

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Restless legs syndrome in a hospital sample of Chinese adult...

Sc（OTf）3-catalyzed three-component cascade reaction:one-pot synthesis of substituted 3-oxoisoindoline-1-carbonitrile derivatives

2015年全国睡眠呼吸学术年会

作者： Jianhua chena Rong Huang Jinmei Luo Yi Xiao xu Zhong Xiuqin Liua

BackgroundrPrevalence rates of restless legs syndrome（RLS）varied in different *** objective of the present study was to investigate the prevalence of RLS in a hospital sample of Chinese adults and explore the sleep quality,fatigue degree and daytime sleepiness of *** also compared the prevalence rates of RLS among Asian populations by literature ***:Consecutive 4739 patients who visited the outpatient clinic with any sleep complaints or leg discomforts were recruited in the *** who were under 18 years old were *** participants answered RLS *** subjects fulfilled all four criteria would be followed up and received advanced examinations to rule out secondary RLS and RLS *** RLS patients were evaluated about the sleep quality,fatigue degree and daytime *** systematically reviewed the studies of the prevalence of RLS in ordinary adult Asian populations published in ***:There were 162（3.42%）subjects fulfilled all four criteria for RLS and 42（0.89%）were diagnosed as primary *** the primary RLS patients,96.6%were poor sleepers,31.0%had anxiety and 10.3%*** were no significant difference of fatigue degree and daytime sleepiness between the patients and *** family history of RLS was 7.1%.Reported prevalence of RLS in Asian countries ranged from 0.1%to 15.31%.Conclusions:The Chinese populations have lower prevalence rates of RLS than North American and Western European *** rates of RLS might vary in different *** RLS and RLS mimics should be excluded before the diagnosis of primary RLS.

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Sc（OTf）3-catalyzed three-component cascade reaction:one-po...