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Solute-solute interactions and their impacts on solute co-segregation and interfacial cohesion of{1012}twin boundary in zinc

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Journal of Materials Science & Technology 2023年第7期138卷 117-128页

作者： Zhifeng huang jian-Feng Nie Department of Materials Science and Engineering Monash UniversityMelbourneVIC 3800Australia

Interactions of solute atoms in biodegradable zinc alloys and their effect on alloy mechanical properties have been less *** this work,the interactions between the common solutes(Li,Mg,Mn,Cu,and Ag)used in the biodegradable Zn alloys,including a solute-solute pair with the same element or with two different elements,are investigated based on first-principles *** is found that the energetically favorable configuration is the third nearest-neighboring for most solute-solute pairs in the bulk lattice because of the relatively strong electronic interaction between solute and Zn atoms or the relatively small local elastic deformation associated with the *** that interfacial cleavage is a key fracture mode of zinc,the segregation ability of these solutes and their effect on the{1012}twin boundary cohesion are also *** result shows that Li tends to fully occupy its preferred site in the twin boundary,while Mg,Mn,Cu,or Ag has a concentration limitation in the twin *** twin boundary cohesion can be significantly enhanced by the segregation of Mn,followed by Cu and Ag,because of the contribution of their d states close to the Fermi ***,the co-segregation ability of two solute atoms in the twin boundary increases with increasing the binding tendency of these two solute atoms in the *** and Li or Mg show a relatively strong co-segregation ability in the twin *** Mn to Zn-Li or Zn-Mg alloys can significantly enhance the resistance to fracture of twin boundaries.

关键词： Zinc alloys Twin boundary Solute-solute interaction Co-segregation Interfacial fracture

Korteweg-de Vries Description of Dark Solitons in Bose-Einstein Condensates

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Chinese Physics Letters 2001年第5期18卷 628-630页

作者： huang Guo-xiang Key Laboratory for Optical and Magnetic Resonance Spectroscopy and Department of Physics East China Normal UniversityShanghai 200062

We investigate the dynamics of pulses in a cigar-shaped Bose-Einstein condensate with repulsive atom-atom interactions without using Thomas-Fermi *** the linear level our results give the Bogoliubov excitation spectrum for sound propagation with speed c=c0/√2,where c_(0) is the speed for the case without *** develop a Korteweg-de Vries(KdV)description for dark soliton propagation in the system and show that it is the quantum pressure that contributes the dispersion necessary for the formation of the dark solitons.

关键词： Einstein soliton propagation

Underdetermined DOA estimation via multiple time-delay covariance matrices and deep residual network

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Journal of Systems Engineering and Electronics 2021年第6期32卷 1354-1363页

作者： CHEN Ying WANG xiang huang Zhitao State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense TechnologyChangsha 410073China

Higher-order statistics based approaches and signal sparseness based approaches have emerged in recent decades to resolve the underdetermined direction-of-arrival(DOA)estimation *** model-based methods face great challenges in practical applications due to high computational complexity and dependence on ideal *** paper presents an effective DOA estimation approach based on a deep residual network(DRN)for the underdetermined *** first extract an input feature from a new matrix calculated by stacking several covariance matrices corresponding to different time *** then provide the input feature to the trained DRN to construct the super resolution *** DRN learns the mapping relationship between the input feature and the spatial spectrum by *** proposed approach is superior to existing model-based estimation methods in terms of calculation efficiency,independence of source sparseness and adaptive capacity to non-ideal conditions(e.g.,low signal to noise ratio,short bit sequence).Simulations demonstrate the validity and strong performance of the proposed algorithm on both overdetermined and underdetermined cases.

关键词： direction-of-arrival(DOA)estimation underdetermined condition deep residual network(DRN) time delay covariance matrix

Recent Development of Chaos Theory in Topological Dynamics

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Acta Mathematica Sinica,English Series 2016年第1期32卷 83-114页

作者： jian LI xiang Dong YE Department of Mathematics Shantou University Wu Wen-Tsun Key Laboratory of Mathematics USTC Chinese Academy of Sciences and School of Mathematics University of Science and Technology of China

We give a summary on the recent development of chaos theory in topological dynamics, focusing on Li-Yorke chaos, Devaney chaos, distributional chaos, positive topological entropy, weakly mixing sets and so on, and the... 详细信息

关键词： Li-Yorke chaos Devaney chaos sensitive dependence on initial conditions distributionalchaos weak mixing topological entropy Furstenberg family

Spatial patterns of the main trees in a plant micro-reserve constructed in the 2022 Beijing Winter Olympics mountainous competition zone

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Journal of Mountain Science 2023年第8期20卷 2228-2241页

作者： WANG jian-yong ZHANG Zhi-xiang School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China

Several plant micro-reserves were established to preserve the vegetation in local mountain areas during the construction of the Yanqing competition zone of the 2022 Beijing Winter *** spatial patterns of the main species in one of the micro-reserves and the factors affecting these patterns were characterized in this *** distribution of arbor species was found to be mostly aggregated,especially at fine scales(<5 m).Minor species were found to be more aggregated than the major species in each forest *** spatial patterns were found to be affected by habitat heterogeneity,intraspecific relationships,interspecific competition,and seed dispersal *** heterogeneity was found to affect large-scale spatial patterns,and its effects were observed throughout population *** competition is another factor affecting the distribution of the species,and its effects were stronger during the later stages of population *** heterogeneity was found to affect competition among species and is key for species *** these processes are affected by the seed dispersal limitation,and intraspecific relationships are a legacy of seed *** point patterns can be used as a tool for the initial assessment of the status of communities within *** consideration of these relationships in the development,management,and formulation of policies for micro-reserves in mountainous areas will facilitate the achievement of conservation *** careful consideration of habitat conditions when selecting sites for micro-reserves establishment can promote species conservation.

关键词： Spatial patterns Point patterns Microreserve Juglans mandshurica forest Beijing mountainous area

Effects of source facies and maturity on individual carbon isotopic compositions of oil

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Geoscience Frontiers 2024年第5期15卷 210-221页

作者： Jingkun Zhang jian Cao Baoli xiang State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China MOE Key Laboratory of Surficial Geochemistry School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China Research Institute of Experiment and Testing PetroChina Xinjiang Oilfield CompanyKaramayXinjiang 834000China

Carbon isotopes have been used extensively in tracing the sources of ***,primary source facies and secondary alteration controls on oil isotopic compositions have not been well resolved,resulting in application uncertainties.A case study was undertaken for an alkaline lacustrine oil system in a lower Permian formation in the Junggar Basin,NW *** indicate that increasing maturity causes the carbon isotopic composition to become heavier for only short–middle-chain compounds,whereas source facies-related carbon assimilation controls the compositions of short-,middle-,and long-chain *** particular,light-carbon assimilation during organic-matter degradation makes the isotopic composition lighter,whereas heavy carbon from the water mass makes it ***,oils in this study area were divided into Type U and Type N oils based on individual compound carbon isotopic compositions,reflecting the difference in source facies in a highly saline and reducing stratified water *** results provide a better understanding of the controls on carbon isotopes in oil in sedimentary basins,reducing the uncertainty in oil–source correlation and addressing the origin of oil.

关键词： Carbon assimilation Water stratification Carbon isotopes Alkaline lacustrine Junggar Basin

An Overview of Metal-Organic Frameworks for Green Chemical Engineering

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Engineering 2021年第8期7卷 1115-1139页

作者： xiang-Jing Kong jian-Rong Li Beijing Key Laboratory for Green Catalysis and Separation&Department of Environmental Chemical Engineering Beijing University of TechnologyBeijing 100124China

Given the current global energy and environmental issues resulting from the fast pace of industrialization,the discovery of new functional materials has become increasingly imperative in order to advance science and technology and address the associated *** boom in metal–organic frameworks(MOFs)and MOF-derived materials in recent years has stimulated profound interest in exploring their structures and *** preparation,characterization,and processing of MOF materials are the basis of their full engagement in industrial *** intensive research in these topics,it is time to promote the practical utilization of MOFs on an industrial scale,such as for green chemical engineering,by taking advantage of their superior *** famous MOFs have already demonstrated superiority over traditional materials in solving real-world *** review starts with the basic concept of MOF chemistry and ends with a discussion of the industrial production and exploitation of MOFs in several *** goal is to provide a general scope of application to inspire MOF researchers to convert their focus on academic research to one on practical *** the obstacles of cost,scale-up preparation,processability,and stability have been overcome,MOFs and MOF-based devices will gradually enter the factory,become a part of our daily lives,and help to create a future based on green production and green living.

关键词： Metal-organic frameworks(MOFs) Application Green chemical engineering

Adversarial data splitting for domain generalization

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Science China(Information Sciences) 2024年第5期67卷 28-42页

作者： xiang GU jian SUN Zongben XU School of Mathematics and Statistics Xi'an Jiaotong University

Domain generalization aims to learn a model that is generalizable to an unseen target domain,which is a fundamental and challenging task in machine learning for out-of-distribution generalization. This paper proposes a novel domain generalization approach that enforces the learned model to be able to generalize well over the train/val subset splitting of the training dataset. This idea is modeled herein as an adversarial data splitting framework, formulated as a min-max optimization problem inspired by the metalearning approach. The min-max optimization problem is solved by iteratively splitting the training dataset into the training and val subsets to maximize the domain shift measured by the objective function and updating the model parameters to enable the model to generalize well from the training subset to the val subset by minimizing the objective function. This adversarial training approach does not assume the known domain labels of the training data; instead, it automatically investigates the “hard” splitting of the train/val subsets to learn the generalizable model. Extensive experimental results using three benchmark datasets demonstrate the superiority of this approach. In addition, we derive a generalization error bound for the theoretical understanding of our proposed approach.

关键词： domain generalization adversarial learning data splitting meta-learning out of distribution

On the Initial Layer and the Limit Behavior for Chemotaxis System with the Effect of Fluid in Fourier Space

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Acta Mathematicae Applicatae Sinica 2024年第4期40卷 1015-1024页

作者： jian-xiang WAN Hai-ping ZHONG Department of Mathematics Jiangxi University of Finance and EconomicsNanchang 330032China School of Mathematics and Computer Yuzhang Normal UniversityNanchang 330103China

The paper deals with a Cauchy problem for the chemotaxis system with the effect of fluid■where d≥*** is known that for each∈>0 and all sufficiently small initial data(u_(0),n_(0),c_(0))belongs to certain Fourier space,the problem possesses a unique global solution(u^(∈),n^(∈),c^(∈))in Fourier *** present work asserts that these solutions stabilize to(u^(∞),n^(∞),c^(∞))as∈^(-1)→***,we show that c^(∈)(t)has the initial layer as∈^(-1)→*** one expects its limit behavior maybe give a new viewlook to understand the system.

关键词： chemotaxis system initial layer limit behavior Fourier space