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Ligand-mediated contaminant degradation by bare and carboxymethyl cellulose-coated bimetallic palladium-zero valent iron nanoparticles in high salinity environments

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Journal of Environmental Sciences 2019年第3期31卷 303-311页

作者： Xiaoming Ma Di He Adele M.Jones T.David Waite Taicheng An Institute of Environmental Health and Pollution Control Guangdong University of Technology Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control School of Environmental Science and Engineering Guangzhou University of Technology School of Civil and Environmental Engineering University of New South Wales

The application of nanoscale zero-valent iron(nZVI) for the degradation of contaminants has been extensively investigated, however, few studies have focused on degradation in high salinity environments. In this study, the ability of bare and carboxymethyl cellulose(CMC)-coated bimetallic Pd-nZVI particles to degrade 33′44′-tetrachlorobiphenyl in high saline water(SW) is examined with particular attention given to the effects of ethylenediaminetetraacetic acid(EDTA) on the rate of degradation. EDTA enhances the reactivity of Pd-nZVI in SW, with evidence provided to link this to the removal of the passivating layer. Additionally, a conceptual model is proposed which provides a quantitative description of the removal of these iron oxide layers in the presence of EDTA. An optimum EDTA to bare Pd-nZVI molar ratio of 0.1 exists, with insufficient EDTA unable to remove the passivating layer whilst excess EDTA results in Fe loss and enhanced agglomeration due to magnetic attraction of the bare Fe(0) particles. In contrast, CMCcoating of Pd-nZVI assemblages actually impedes degradation, despite the coated particles displaying a smaller average size compared to uncoated particles, with even the presence of EDTA in this case not significantly improving degradation. The reduced reactivity in the presence of CMC is primarily attributed to the effect of CMC on the association of Pd with nZVI particles. In particular, the presence of CMC reduced the total amount of Pd incorporated with the stabilized particles compared to the non-stabilized particles.Additionally, the presence of CMC results in less Pd present in its reactive zero-valent oxidation state.

关键词： Bimetallic zero valent iron ligand-mediated depassivation polychlorinated biphenyls high salinity water

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zero chiral bulk modes in 3D Weyl metamaterials

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Science Bulletin 2019年第12期64卷 799-801页

作者： Yang Ming Cheng-Wei Qiu School of Physics and Electronic Engineering Changshu Institute of TechnologySuzhou 215000China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore

In the Weyl semimetals, a special type of one-way chiral zero mode (CZM) can be supported if a strong magnetic field is applied. The corresponding CZM is related to the zero-order Landau level for relativistic particles in Dirac or Weyl systems. This special energy level can lead to chiral anomaly, which describes the phenomenon of breaking the conservation of chirality [1]. Under the action of an effective magnetic field, the zeroth Landau mode can be expected to propagate only in the chiral direction according to the chirality (left-handed or right-handed) of the Weyl points and the magnetic field direction. Distinguished from the topological insulators, such a one-way propagation mode is a bulk state rather than a surface state or edge state that travels along the interface. Recently, the discovery of Dirac or Weyl degeneracies in the electronic and photonic systems brings opportunities for experimental detection of the chiral zeroth Landau levels [2,3]. Notwithstanding, the chiral Landau level in the 3D photonic system has not been observed yet.

关键词： chiral zero mode(CZM) chirality topological insulators

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Lowest-energy moiré band formed by Dirac zero modes in twisted bilayer graphene

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Science Bulletin 2019年第8期64卷 495-498页

作者： Long Zhang Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Physical Science Laboratory Huairou National Comprehensive Science Center

The recent discovery of an unconventional insulating phase and an adjacent superconducting (SC) phase in the twisted bilayer graphene (TBG)[1,2] has triggered great excitement (3–11)The two layers of graphene are rot... 详细信息

关键词： band formed by Dirac zero modes in twisted bilayer graphene Lowest-energy moir

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zero extension for Poisson's equation

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Science China Mathematics 2020年第4期63卷 721-732页

作者： Yongyong Cai Shulin Zhou Beijing Computational Science Research Center Beijing 100193China LMAM and School of Mathematical Sciences Peking UniversityBeijing 100871China

In this paper,we present a necessary and sufficient condition to guarantee that the extended function of the solution for Poisson's equation in a smaller domain by zero extension is still the solution of the corresponding extension problem in a larger domain.We prove the results under the frameworks of classical solutions,strong solutions and weak solutions.Furthermore,we give some observations for the nonlinear pLaplace equation.

关键词： Poisson's equation zero extension a necessary and sufficient condition

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Scientometric of Nearly zero Energy Building Research: A Systematic Review from the Perspective of Co-Citation Analysis

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Journal of Thermal Science 2019年第6期28卷 1104-1114页

作者： WANG Mengmeng LIU Xiaojun FU Hanliang CHEN Baiyu School of Management Xi’an University of Architecture and TechnologyXi’an 710055China College of Engineering University of California BerkeleyCA 94720USA Department of Technology Illinois State UniversityIL 61790-0001USA

As an important building type to diminish energy use and greenhouse gas emissions in the construction industry, nearly zero energy building(nZEB) has attracted much attention from many scholars, with volumes of research findings published. However, quantitative and systematic reviews on those findings are rarely conducted by researchers. Therefore, a visualized presentation regarding the advancement of nZEB research was made in this study by applying the scientometric method of co-citation analysis to 704 publications retrieved from the Web of Science database from 2006 to 2018. Here, the key conclusions drawn after the research are as follows:(1) Italy, the USA and Spain are the top three nations by the number of nZEB publications;(2) Energy and Buildings, Applied Energy and Energy are the journals with the highest number of published nZEB articles;(3) Politecnico di Milano, Aalto University and Politecnico di Torino are the most influential core organizations in the field of nZ EB;(4) Professor Kurnitski J, Professor Corgnati SP and Professor D’Agostino D are the leading nZEB experts;(5) "cost optimal", "life cycle assessment", "technical system", "design" and "indoor environment quality" are the major research directions in the field of nZEB;(6) A multi-stage optimization method for cost-optimal and nearly zero-energy building solutions in line with the EPBD 2010, co-authored by Hamdy M, is the most cited nZEB reference;(7) "residential building", "building energy saving technology", "simulation method" and "thermal comfort", etc. are the hot topics in nZEB research at present and in the future. This research is designed to provide valuable information for scholars interested in the field of nZEB.

关键词： nearly zero energy building(nZEB) scientometric co-citation CiteSpace

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Classification of topological trivial matter with non-trivial defects

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Science Bulletin 2019年第9期64卷 575-579页

作者： Lokman Tsui Zi-Xiang Li Yen-Ta Huang Steven G. Louie Dung-Hai Lee Department of Physics University of California Materials Sciences Division Lawrence Berkeley National Laboratory

In this paper, we apply the K-theory to classify topological trivial fermionic phases which, nonetheless,host symmetry-protected non-trivial defects. An important implication of our work is that the existence of Majorana zero mode in the vortex core is neither a necessary nor a sufficient condition for the superconductor in question being topologically non-trivial.

关键词： Majorana zero mode Symmetry protected topological phase Topological superconductor Topological defect K-theory

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Minimal setup for non-Abelian braiding of Majorana zero modes

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Science China(Physics,Mechanics & Astronomy) 2021年第11期64卷 127-132页

作者： Jie Liu Wenqin Chen Ming Gong Yijia Wu XinCheng Xie Ministry of Education Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter School of PhysicsXi’an Jiaotong UniversityXi’an 710049China International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Beijing Academy of Quantum Information Sciences Beijing 100193China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

Braiding Majorana zero modes(MZMs)is the key procedure toward topological quantum computation.However,the complexity of the braiding manipulation hinders its experimental realization.Here we propose an experimental setup consisting of MZMs and a quantum dot state which can substantially simplify the braiding protocol of MZMs.Such braiding scheme,corresponding to a specific closed loop in the parameter space,is quite universal and can be realized in various platforms.Moreover,the braiding results can be measured and manifested through electric current,providing a simple and novel way to detect the non-Abelian statistics of MZMs.

关键词： non-Abelian statistics geometric phase Majorana zero modes

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Levy Constrained Search in Fock Space：An Alternative Approach to Noninteger Electron Number

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物理化学学报 2018年第6期34卷 625-630页

作者： AYERS Paul W. LEVY Mel Department of Chemistry and Chemical Biology McMaster University Hamilton Ontario L8S 4M1 Canada. Department of Physics North Carolina A&T State University Greensboro NC 27411 USA. Department of Chemistry Duke University Durham NC 2770

By extending the Levy wavefunction constrained search to Fock Space,one can define a wavefunction constrained search for electron densities in systems having noninteger number of electrons.For pure-state v-representable densities,the results are equivalent to what one would obtain with the zero-temperature grand canonical ensemble.In other cases,the wavefunction constrained search in Fock space presents an upper bound to the grand canonical ensemble functional.One advantage of the Fock-space wavefunction constrained search functional over the zero-temperature grand-canonical ensemble constrained search functional is that certain specific excited states(i.e.,those that are not ground-statev-representable) are the stationary points of the Fock-space functional.However,a potential disadvantage of the Fock-space constrained search functional is that it is not convex.

关键词： Density functional theory Levy constrained search functional Fock space Fractional electron number Excited-state density functional theory Universal density functional zero temperature grand canonicalensemble Convexity

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A new insight into promotion action of Co2+ in Ni-diamond composite electrodeposition

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Journal of Materials Science & Technology 2019年第8期35卷 1797-1802页

作者： Haifei Zhou Nan Du Jingdong Guo Shuan Liu Zhejiang Electric Power Corporation Research Institute Hangzhou 310014 China Nanchang Hangkong University Nanchang 330063 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Ningbo Institute of Material Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China

A new insight into the promotion action of Co^2+ on both particle and metal deposition in Ni-diamond composite electrodeposition system was analyzed according to electrochemical measurements. The results showed that the addition of Co^2+ made particles content in deposits increased remarkably. The change of particles content in deposits was related inversely to the change of cathodic zero potential with the increase of the concentration of cobalt sulfate. zero charge potential of cathode was shifted to much more negative region. The negative shift of the zero potential, combining with positive shift of the zeta potential, increased the electrostatic force between the particle-adsorbed metallic cations and the cathode. It not only benefits to the transportation of particles in solution towards cathode, but also shortens their residence time on cathodic surface. Meanwhile, entry of particles is also promoted. For metals deposition,reduction resistance of metallic cations rises greatly and deposition current at cathodic potentiodynamic polarization decreases after cobalt sulfate has been added into electrolyte. These factors are favorable for increasing particles content in deposits. In addition, physical model of diamond particles deposition state before and after the addition of Co^(2+)has been discussed.

关键词： Cobalt sulfate Composite electrodeposition Ni-diamond zero charge potential Particle content in deposits

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Application of novel force control strategies to enhance robotic abrasive belt grinding quality of aero-engine blades

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Chinese Journal of Aeronautics 2019年第10期32卷 2368-2382页

作者： Xiaohu XU Dahu ZHU Haiyang ZHANG Sijie YAN Han DING State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430074China Wuxi CRRC Times Intelligent Equipment Co. Ltd.Wuxi 214174China

Robotic belt grinding has emerged as a finishing process in recent years for machining components with high surface finish and flexibility.The surface machining consistency,however,is difficult to be guaranteed in such a process.To overcome this problem,a method of hybrid force-position control combined with PI/PD control is proposed to be applied in robotic abrasive belt grinding of complex geometries.Voltage signals are firstly obtained and transformed to force information with signal conditioning methods.Secondly,zero drift and gravity compensation algorithms are presented to calibrate the F/T transducer which is installed on the robot end-effector.Next,a force control strategy combining hybrid force-position control with PI/PD control is introduced to be employed in robotic abrasive belt grinding operations where the force control law is applied to the Z direction of the tool frame and the positon control law is used in the X direction of the tool frame.Then,the accuracy of the F/T transducer and the robotic force control system is analyzed to ensure the stability and reliability of force control in the robotic grinding process.Finally,two typical cases on robotic belt grinding of a test workpiece and an aero-engine blade are conducted to validate the practicality and effectiveness of the force control technology proposed.

关键词： Gravity compensation Hybrid force-position control PI/PD control Robotic belt grinding zero drift compensation

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