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New family of Dirac and Weyl semimetals in XAuTe(X=Na, K,Rb) ternary honeycomb compounds

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Science China(Physics,Mechanics & Astronomy) 2016年第10期59卷 66-71页

作者： Hao Sun Jin zhao International Center for Quantum Design of Functional Materials/Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics Chinese Academy of Sciences and Department of Physics University of Science and Technology of China Synergetic Innovation Center of Quantum Information & Quantum Physics University of Science and Technology of China Department of Physics and Astronomy University of Pittsburgh

We propose a new family of 3D Dirac semimetals based on XAuTe(X = K, Na, Rb) ternary honeycomb compounds, determined based on first-principles calculations, which are shown to be topological Dirac semimetals in which the Dirac points are induced by band inversion. Dirac points with four-fold degeneracy that are protected by C3 rotation symmetry and located on the Γ-A high-symmetry path are found. Through spatial-inversion symmetry breaking, a K(Au0.5 Hg0.5)(Te0.5As0.5) superlattice structure composed of KHgAs and KAuTe compounds is proven to be a Weyl semimetal with type-II Weyl points, which connect electronand hole-like bands. In this superlattice structure, the six pairs of Weyl nodes are distributed along the K-Γ high-symmetry path on the kz = 0 plane. Our research expands the family of topological Dirac and type-II Weyl semimetals.

关键词： Dirac semimetal type-II Weyl semimetal band inversion

Tianwen-1 and China's Mars exploration program

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National Science Review 2021年第2期8卷 170-173页

作者： Weijie zhao 机构不详

About every 26 months, the distance between Earth and Mars reaches a minimum, and that is the best time window for Mars exploration from Earth. In July 2020, three spacecraft started their journey to Mars: the Hope orbiter of the United Arab Emirates, the Tianwen-1 mission of China and the Perseverance rover of the United States’ National Aeronautics and Space Administration(NASA). If all go well,these spacecraft will reach Martian orbit in February 2021 and start their scientific ***-1 is China’s first mission to Mars. It includes an orbiter, a lander and a rover. It carries 13 scientific payloads and will investigate the topography, soil composition, water-ice distribution, internal structure, atmospheric environment and physical fields(electromagnetic and gravitational) of Mars. In this interview, we talked with the mission’s Chief Scientist Yongxin Pan() and Scientific Payload Sub-System Director Chi Wang() about this scientific mission and China’s future plans for Mars exploration.

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Numerical simulation and scaling analysis of elasticity-induced lift force in a viscoelastic fluid between confining surfaces

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Journal of Hydrodynamics 2022年第4期34卷 756-766页

作者： Xin zhao Chao Wei The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China Science and Technology on Vehicle Transmission Laboratory Beijing Institute of TechnologyBeijing 100081China

How to accurately characterize the lift force on the particles near the solid surfaces is an ongoing challenge in fluid mechanics and microfluidic techniques, especially in a complex system with viscoelastic fluid or/and soft surface that is commonly encountered in a biological system. The motions of the particles in vicinity of a surface can be simplified to be a rigid cylinder surrounded by the viscoelastic fluid moving along a substrate which can be rigid or soft according to different cases. In such an inertial free system with a wide range of Weissenberg number (Wi < 5.00, representing the ratio of the elastic force to the viscous force), firstly we numerically evaluate the influence of the systematic parameters, including the polymer viscosity, the geometry and Wi, on the net normal force for a cylinder closely moving along a rigid substrate, and the elasticity-induced lift force in a scaled form. It is shown that a strong shear arises in the viscoelastic confinement between the moving cylinder and the rigid substrate, it leads to the asymmetry of the first normal stress distribution around the cylinder, and thus the lift force. Then, the influence of a soft substrate on the lift force is considered, and we find that the lift force induced by the viscoelastic fluid always dominates in magnitude over that induced by the soft substrate deformation. This work provides a reliable scaling that can be utilized to quantify the elasticity-induced lift force on the particles in a viscoelastic system, such as the micro- and nanofluidic systems in biological applications.

关键词： Viscoelastic fluid scaling expression computational fluid dynamics lift force

Functional mesoporous materials

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Nano Research 2021年第9期14卷 2888-2890页

作者： Dongyuan zhao Laboratory of Advanced Materials Faculty of Chemistry and MaterialsShanghai Key Lab of Molecular Catalysis and Innovative Materialsand State Key Laboratory of Molecular Engineering of PolymersFudan UniversityShanghai 200433China

The Nano Research Award,established by Nano Research together with Tsinghua University Press(TUP)and Springer Nature in 2013,is awarded for outstanding contributions in nanoscience and nanotechnology by individual scientists in all the *** winners are selected by the Award Committee after receiving *** date,the Nano Research Award has been awarded to 12 scientists.I am very honored to receive the Nano Research Award in 2020,with *** recognition is greatly an acknowledgement of the scientific advances achieved by my graduate students and postdoctoral fellows-laborious,talented,dedicated,creative,collaborative people,of the very highest *** topics of this special issue span a wide range,as a powerful set of projects at the forefront of nanoscience and nanotechnology,briefly summarized by topic area as follows:nanoelectronic-photonic devices and functional mesoporous *** has introduced the recent progresses about the nanoelectronic-photonic devices.

关键词： summarized award mesoporous

β‑Hydroxybutyric acid improves cognitive function in a model of heat stress by promoting adult hippocampal neurogenesis

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Stress Biology 2022年第1期2卷 1-17页

作者： Jian Huang Yongji Wu Xuejun Chai Shuai Wang Yongkang zhao yan Hou Yue Ma Shulin Chen Shanting zhao Xiaoyan Zhu College of Veterinary Medicine Northwest A&F UniversityYanglingShaanxi 712100People’s Republic of China Department of Basic Medicine Xi’an Medical UniversityXi’anShaanxi 710021People’s Republic of China

Heat stress has multiple potential effects on the brain,such as neuroinflammation,neurogenesis defects,and cog-nitive impairment.β-hydroxybutyric acid(BHBA)has been demonstrated to play neuroprotective roles in various models of neurological *** the present study,we investigated the efficacy of BHBA in alleviating heat stress-induced impairments of adult hippocampal neurogenesis and cognitive function,as well as the underlying *** were exposed to 43℃for 15 min for 14 days after administration with saline,BHBA,or ***,we showed for the first time that BHBA normalized memory ability in the heat stress-treated mice and attenuated heat stress-impaired hippocampal ***,BHBA noticeably improved the synaptic plasticity in the heat stress-treated hippocampal neurons by inhibiting the decrease of synapse-associated proteins and the density of dendritic ***,BHBA inhibited the expression of cleaved caspase-3 by suppressing endoplasmic reticu-lum(ER)stress,and increased the expression of brain-derived neurotrophic factor(BDNF)in the heat stress-treated hippocampus by activating the protein kinase B(Akt)/cAMP response element binding protein(CREB)and methyl-CpG binding protein 2(MeCP2)*** findings indicate that BHBA is a potential agent for improving cogni-tive functions in heat stress-treated *** action may be mediated by ER stress,and Akt-CREB-BDNF and MeCP2 pathways to improve adult hippocampal neurogenesis and synaptic plasticity.

关键词： β-Hydroxybutyric acid Heat stress Adult hippocampal neurogenesis Synaptic plasticity Cognitive dysfunctions

Preparation and characterization of highly photocatalytic active hierarchical BiOX(X=Cl,Br,I)microflowers for rhodamine B degradation with kinetic modelling studies

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Journal of Central South University 2017年第4期24卷 754-765页

作者： GU Ying-ying zhao Li yanG Ming-yang XIONG Yi-qiu WU Zhe ZHOU Min-jia yan Jun School of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China

The hierarchical BiOX(X=Cl, Br, I) microflowers were successfully synthesized via simple precipitation method at 160 ℃ for 24 h and characterized by XRD, SEM, TEM, UV-vis DRS and N_2 adsorption-desorption techniques. The as-prepared samples were pure phases and of microflowers composed of nanosheets which intercrossed with each other. The specific surface areas were about 22.9, 17.3 and 16.2 m^2/g for BiOCl, BiOBr and BiOI, respectively. The photocatalytic activities of BiOX powers were evaluated by RhB degradation under UV-vis light irradiation in the order of BiOCl > BiOBr > BiOI. Also, the kinetics of RhB degradation over BiOI was selectively investigated, demonstrating that the kinetics of Rh B degradation follows apparent first-order kinetics and fits the Langmuir-Hinshelwood model.

关键词： microstructure semiconductors photocatalysis BiOX

Finite-Time Convergence Disturbance Rejection Control for a Flexible Timoshenko Manipulator

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IEEE/CAA Journal of Automatica Sinica 2021年第1期8卷 157-168页

作者： Zhijia zhao Zhijie Liu the School of Mechanical and Electrical Engineering Guangzhou UniversityGuangzhou 510006China the School of Automation and Electrical Engineering University of Science and Technology Beijing(USTB)Beijing 100083 Shunde Graduate School of USTB Foshan 528300China

This paper focuses on a new finite-time convergence disturbance rejection control scheme design for a flexible Timoshenko manipulator subject to extraneous *** suppress the shear deformation and elastic oscillation,position the manipulator in a desired angle,and ensure the finitetime convergence of disturbances,we develop three disturbance observers(DOs)and boundary *** the derived DOs-based control schemes,the controlled system is guaranteed to be uniformly bounded stable and disturbance estimation errors converge to zero in a finite *** the end,numerical simulations are established by finite difference methods to demonstrate the effectiveness of the devised scheme by selecting appropriate parameters.

关键词： Disturbance observer disturbance rejection control finite-time convergence Timoshenko manipulator vibration control

AN ALGORITHM FOR DETERMINATION OF AGE-SPECIFIC FERTILITY RATE FROM INITIAL AGE STRUCTURE AND TOTAL POPULATION

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Journal of Systems Science & Complexity 2012年第5期25卷 833-844页

作者： Zhixue zhao Baozhu GUO Academy of Mathematics and Systems Science Chinese Academy of Sciences School of Mathematical Sciences Shanxi University School of Computational and Applied Mathematics University of the WitwatersrandWits 2050JohannesburgSouth Africa.

Age-specific fertility rate and total fertility rate of females are the most important parame- ters in population dynamics. This paper proposes an algorithm to get these parameters from the initial age distribution and the total population the years followed. The idea is natural in the sense that the total population is easily to be obtained in a closed society. The authors use a discrete population model to formulate this problem into an inverse problem, which is ill-posed generally. A necessary and sufficient condition for the identifiability is established. An algorithm for reconstruction of age-specific fertility rate is developed.

关键词： Parameter identification population dynamics.

Wetland Purification Pattern for Surface Runoff Pollution of Coastal Highway in Liaoning Province

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Asian Agricultural Research 2015年第1期7卷 44-47页

作者： yanbo zhao Wenzhi yan Hongwei yan College of Horticulture Shenyang Agricultural University Key Laboratory of Northern Landscape Plants and Regional Landscape Educational Department of Liaoning Province Housing Urban and Rural Construction Department of Liaoning Province

Taking surface runoff of Coastal Highway in Liaoning Province as research object,this paper analyzed water quality characteristics of runoff and flow rules of pollutants. It proposed using constructed wetland treatment technique in the drainage system from the perspective of effectively removing major pollutants. Using the constructed wetland k- C* model and relevant experience,parameters of constructed wetland can be obtained. The basic model is as follows: constructed wetland lies in two sides of the road,and surface runoff sewage is collected and treated separately with 1 km road section as the collection unit. The wetland area in one side is 191. 6 m2,average water depth is 0. 5 m,wetland width is 8 m,and wetland length is 24 m.

关键词： Surface runoff Runoff pollution Constructed wetlan