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Seasonal freezing-thawing process and hydrothermal characteristics of soil on the Loess Plateau, China

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Journal of Mountain Science 2021年第11期18卷 3082-3098页

作者： CHOU Ya-ling WANG li-jie Key Laboratory of Disaster Prevention and Mitigation in Civil engineering of Lanzhou University of Technology Lanzhou 730050China

In seasonally frozen soil regions,freezing-thawing action and hydrothermal effect have strong influence on physical and mechanical behavior of shallow soil.A field experiment on the Loess Plateau in Northwest China was carried out to analyze the freezing-thawing process and hydrothermal characteristics of shallow soil considering the climate *** results show that the maximum seasonal freezing depth under bare ground surface in this area is from 20 cm to 50 *** ground temperature shows a similar changing trend with air temperature,but it has lagged behind the air temperature,and the ground temperature amplitude exponentially decreases with the increase of soil *** seasonally frozen soil has experienced four typical stages:unfrozen period,alternate freezing period,freezing period and alternate thawing *** freezing-thawing process is characterized by unidirectional freezing and bidirectional *** water content of shallow soil is significantly affected by air temperature,evaporation and precipitation,and the soil water content shows a"low-high-low"changing trend with the increase of *** soil temperature and water content interact with each other,and are often *** variation trend of soil moisture with time is consistent with the change trend of the ground temperature with time in each soil layer,andthe degree of consistency is higher in the near surface soil than that in the lower ***,the spatial-temporal characteristics of soil moisture and temperature is that the volumetric water content and ground temperatureof near surface soil have strong variability,and the range valueKa and coefficient of variation Cvof soil water content and ground temperaturein different seasons show a decreasing trend with the increase of depth.

关键词： Seasonally frozen soil Freezing-thawing process Hydrothermal characteristics Loess Plateau

Minimal Representations of Cuntz Algebras

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Acta Mathematica Sinica,english Series 2020年第7期36卷 749-764页

作者： ling Juan Ye li Ning JIANG School of Mathematics and Statistics Beijing Institute of TechnologyBeijing 100081P.R.China

Suppose that O_n(2 ≤ n ≤∞) is a Cuntz algebra. There exists a number 1 ≤ k(π, Ω) ≤∞such that if the cyclic representations(H, π, Ω) and(H, π, Ω) of the Cuntz algebra O_n are unitary equivalent, k(π, Ω) = k(π, Ω). Applying the number, one can define a minimal representation of O_n and give a sufficient condition of the minimality for a representation of O_n. Moreover, the relations between minimal states and minimal representations of Cuntz algebras and the relations between the minimality and the irreducibility of the representation of O_n are investigated, respectively.

关键词： algebra. O_n representation

liquid-phase epoxidation of propylene with molecular oxygen by chloride manganese meso-tetraphenylporphyrins

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Chinese Journal of Chemical engineering 2022年第8期35卷 61-65页

作者： Xian-Tai Zhou ling-ling Wang Yang li Hong-Bing Ji Fine Chemical Industry Research Institute School of Chemical Engineering and TechnologySun Yat-sen UniversityZhuhai 519082China Fine Chemical Industry Research Institute School of ChemistrySun Yat-sen UniversityGuangzhou 510275China School of Chemical engineering Guangdong University of Petrochemical TechnologyMaoming 525000China

Propylene molecule owns two active sites,the direct epoxidation of propylene by dioxygen is still a challenge due to the limitation of *** this work,the direct liquid-phase propylene aerobic epoxidation protocol by chloride manganese meso-tetraphenylporphyrin(MnTPPCl)was *** conversion of propylene was 12.7%,and the selectivity towards PO(propylene oxide)reached up to 80.5%.The formation of PO was attributed to the mechanism via high-valent Mn species,which was confirmed by means of in situ UV–vis spectrum.

关键词： Propylene epoxidation Dioxygen Manganese porphyrins liquid phase

Self-assembled liquid crystal architectures for soft matter photonics

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light(Science & Applications) 2022年第12期11卷 2849-2872页

作者： ling-ling Ma Chao-Yi li Jin-Tao Pan Yue-e.Ji Chang Jiang Ren Zheng Ze-Yu Wang Yu Wang Bing-Xiang li Yan-Qing Lu National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and ManipulationCollege of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210023China College of electronic and Optical engineering&College of Flexible electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Self-assembled architectures of soft matter have fascinated scientists for centuries due to their unique physical properties originated from controllable orientational and/or positional orders,and diverse optic and photonic *** one could know how to design,fabricate,and manipulate these optical microstructures in soft matter systems,such as liquid crystals(LCs),that would open new opportunities in both scientific research and practical applications,such as the interaction between light and soft matter,the intrinsic assembly of the topological patterns,and the multidimensional control of the light(polarization,phase,spatial distribution,propagation direction).Here,we summarize recent progresses in self-assembled optical architectures in typical thermotropic LCs and bio-based lyotropic *** briefly introducing the basic definitions and properties of the materials,we present the manipulation schemes of various LC microstructures,especially the topological and topographic *** work further illustrates external-stimuli-enabled dynamic controllability of self-assembled optical structures of these soft materials,and demonstrates several emerging ***,we discuss the challenges and opportunities of these materials towards soft matter photonics,and envision future perspectives in this field.

关键词： architectures topological originated

Characteristics of TIG arc-assisted laser welding–brazing joint of aluminum to galvanized steel with preset filler powder

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Rare Metals 2015年第9期34卷 650-656页

作者： Chun-ling li Ding Fan Bin Wang State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology

Tungsten inert gas(TIG) arc-assisted laser welding–brazing was used for the butt joining of 5A06 aluminum alloy to the galvanized steel by preset filler powder without groove. The spreading behavior of liquid metal on the back of the galvanized steel at different assisted welding currents was also investigated. The results show that the assisted TIG arc optimizes the interface reaction temperature, enhances the wettability of liquid metal on the steel side, and forms a sound butt joint at an appropriate welding current. A non-uniform intermetallic compound is formed at the interfacial layer, which is composed of Fe2Al5 close to the steel substrate and Fe4Al13 close to the solidified aluminum. The superior tensile strength of joint is indicated when the welding current ranges from 13 to 16 A. The average tensile strength can reach 151 MPa at the welding current of 16 A, and the corresponding fracture belongs to the ductile and brittle hybrid mode.

关键词： Aluminum alloy Steel Welding–brazing Welding curre

Iridium-catalyzed direct ortho-C–H amidation of benzoic acids with sulfonylazides

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Chinese Chemical Letters 2015年第11期26卷 1336-1340页

作者： Ming-e Wei lian-Hui Wang Yu-Dong li Xiu-ling Cui engineering Research Center of Molecular Medicine Ministry of Educationthe Key Laboratory of Xiamen Marine and Gene Drugs Institute of Molecular Medicine and School of Biomedical Sciences Huaqiao University

A mild and efficient iridium-catalyzed ortho-C-H amidation with sulfonyl azides by weakly coordinating carboxylic acid was demonstrated, which provided a novel approach to anthranilic acid derivatives.

关键词： lr-catalysisBenzoic acidSulfonyl azidesC-H bond amination

Nonsmooth dynamic analysis of rigid-flexible interaction collision

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Applied Mathematics and Mechanics(english edition) 2022年第11期43卷 1731-1746页

作者： ling TAO Zhongpan li Yan li Huijian CHeN Zhiqiang FeNG School of Mechanics and Aerospace engineering Southwest Jiaotong UniversityChengdu 610031China Laboratoire de Mécanique et d'energétique d'evry Univ-evry Université Paris-SaclayEvry 91020France

This paper aims to explore the deformation of the collided bodies in multibody systems and to effectively simulate the motion path of colliding ***,we describe the geometrically nonlinear problems of materials by the total Lagrangian ***,a first-order integration scheme is used to solve the dynamics *** algorithm combining the bi-potential method with the node-to-point contact identification is proposed to solve the interface problems of rigid-flexible interaction *** observe the collision process more intuitively,the internal software FeR/VIeW is introduced to visualize the *** accuracy is proved by comparing the proposed method with the analytical solution or another numerical ***,the proposed method has more numerical robustness,such as occupying less computer storage,saving the computational cost,and broadening the application range of the bi-potential method.

关键词： collision bi-potential method node-to-point rigid-flexible FeR/VIeW

extraction and isolation of the salidroside-type metabolite from zinc(Zn) and cadmium(Cd) hyperaccumulator Sedum alfredii Hance

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第10期13卷 839-845页

作者： Yan XING Hong-yun PeNG Xia li Meng-xi ZHANG ling-ling GAO Xiao-e YANG Ministry of education Key Laboratory of environmental Remedia-tion and ecological Health College of Environmental and ResourceSciencesZhejiang UniversityHangzhou 310058China State Key Laboratory of Hydrology-Water Resources and Hydraulicengineering Hohai UniversityNanjing 210098China

The active metabolite in the post-harvested biomass of zinc(Zn) and cadmium(Cd) hyperaccumulator Sedum alfredii Hance from phytoextraction is of great interest in *** current study demonstrates that a salidroside-type metabolite can be yielded from the Zn/Cd hyperaccumulator *** biomass by means of sonication/ethanol extraction and macroporous resin column(AB-8 type) *** concentrations of Zn and Cd in the salidroside-type metabolite were below the limitation of the national standards.

关键词： Salidroside-type metabolite Isolation Hyperaccumulator Sedum alfredii Hance

Insights into the Roles of Melatonin in Alleviating Heavy Metal Toxicity in Crop Plants

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Phyton-International Journal of experimental Botany 2021年第6期90卷 1559-1572页

作者： ling li Xuyu Yan Shaanxi Key Laboratory of Chinese Jujube College of Life ScienceYan’an UniversityYan’an716000China

Alleviating heavy metal pollution in farmland soil,and heavy metal toxicity in plants is the focus of global agricultural environmental *** is a kind of indoleamine compound that wide exists in organisms;it is currently known as an endogenous free radical scavenger with the strongest antioxidant *** a new plant growth regulator and signaling molecule,melatonin plays an important role in plant resistance to biotic or abiotic *** studies indicate that melatonin can effectively alleviate heavy metal toxicity in crop plants,which provides a new strategy to minimize heavy metal pollution in crop *** study summarizes the research progress on the role of melatonin in alleviating heavy metal toxicity in crop plants and the related physiological and ecological mechanisms such as reducing the concentration of heavy metals in the rhizosphere,fixing and regionally isolating of heavy metals,maintaining the mineral element balance,enhancing the antioxidant defense system and interacting with hormonal ***,future prospects for the mechanism of melatonin in regulating heavy metal toxicity,the pathway regulating synthesis and catabolism,and the interaction mechanism of melatonin signaling and other phytohormones are presented in this paper,with the goal of providing a theoretical basis for controlling heavy metal ion accumulation in crop plants grown in contaminated soil.

关键词： Melatonin crop plant heavy metal toxicity biosynthesis alleviation mechanism