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Preliminary computation of the gap eigenmode of shear Alfvén waves on the LAPD

Chinese Physics B 2018年第12期27卷 381-389页

作者： lei chang School of Aeronautics and Astronautics Sichuan University

Characterizing the gap eigenmode of shear Alfv′en waves(SAWs) and its interaction with energetic ions is important to the success of magnetically confined fusion. Previous studies have reported an experimental observation of the spectral gap of SAW on the on Large Plasma Device(LAPD)(Zhang et al. 2008 Phys. Plasmas 15 012103), a linear large plasma device(Gekelman et al. 1991 Rev. Sci. Instrum. 62 2875) possessing easier diagnostic access and lower cost compared with traditional fusion devices, and analytical theory and numerical gap eigenmode using ideal conditions(chang 2014 Ph.D Thesis at Australian National University). To guide experimental implementation, the present work models the gap eigenmode of SAWs using exact LAPD parameters. A full picture of the wave field for previous experiment reveals that the previously observed spectral gap is not global but an axially local result. To form a global spectral gap, the number of magnetic mirrors has to be increased and stronger static magnetic field makes it clearer. Such a spectral gap is obtained for the magnetic field of B0(z) = 1.2 + 0.6 cos[2π(z-33.68)/3.63] with 7.74-m magnetic beach. By introducing two types of local defects(corresponding to Eθ(z0) = 0 and E’θ(z0) = 0 respectively), odd-parity and even-parity discrete eigenmodes are formed clearly inside the gap. The strength of these gap eigenmodes decreases significantly with collision frequency, which is consistent with previous studies. Parameter scans show that these gap eigenmodes can be even formed successfully for the field strength of B0(z) = 0.2 + 0.1 cos[2π(z-33.68)/3.63] and with only four magnetic mirrors, which are achievable by the LAPD at its present status. This work can serve as a strong motivation and direct reference for the experimental implementation of the gap eigenmode of SAWs on the LAPD and other linear plasma devices.

关键词： gap eigenmode shear Alfvén wave LAPD number and depth of magnetic mirror linear plasma

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A variable weight approach for evidential reasoning

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Journal of Central South University 2013年第8期20卷 2202-2211页

作者： chang lei-lei LI Meng-jun JIANG Jiang College of Information System and Management National University of Defense Technology Changsha 410073 China Department of Mathematics University of Birmingham Birmingham B 152TT UK

A variable weight approach was proposed to handle the probability deficiency problem in the evidential reasoning （ER） approach. The probability deficiency problem indicated that the inadequate information in the assessment result should be less than that in the input. However, it was proved that under certain circumstances, the ER approach could not solve the probability deficiency problem. The variable weight approach was based on two assumptions： 1） the greater weight should be given to the rule with more adequate information; 2） the greater weight should be given to the rules with less disparate information. Assessment results of two notional case studies show that 1） the probability deficiency problem is solved using the proposed variable weight approach, and 2） the information with less inadequacy and more disparity is provided for the decision makers to help reach a consensus.

关键词： probability deficiency evidential reasoning (ER) inadequate information variable weight consensus

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A pattern for the flavor dependent quark-antiquark interaction

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Chinese Physics C 2019年第11期43卷 85-90页

作者： Muyang Chen lei chang School of Physics Nankai UniversityTianjin 300071China

A flavor dependent kernel is constructed based on the rainbow-ladder truncation of the Dyson-Schwinger and Bethe-Salpeter equations in quantum *** quark-antiquark interaction is composed of a flavor dependent infrared part and a flavor independent ultraviolet *** model gives a successful and unified description of the light,heavy and heavy-light ground state pseudoscalar and vector *** model shows,for the first time,that the infrared enhanced quark-antiquark interaction is stronger and wider for lighter quarks.

关键词： Dyson-Schwinger equation Bethe-Salpeter equation heavy-light mesons flavor dependence

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Reaction characteristics and kinetics of gallium in chlorination roasting of copper tailings using calcium chloride

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Rare Metals 2022年第3期41卷 1063-1070页

作者： chang lei Tao Chen Bo Yan Xian-Ming Xiao State Key Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China University of Chinese Academy of Sciences Beijing 100082China

The mineral composition of copper tailings was examined, and the phase analysis of gallium was conducted for recovery of the rare scattered metal gallium from copper tailings. The reaction characteristics and kinetics of gallium in the chlorination roasting of copper tailings were investigated in a tube furnace apparatus under different conditions, including roasting temperature, quantity of chlorination agent,roasting time, and airflow. Calcium chloride was chosen for the chlorination reaction because it is highly effective for volatilization of metals. The results show that gallium mainly exists in limonites in the form of oxides, and increases in roasting temperature, quantity of chlorination agent, and roasting time are conducive to increasing the chloridizing volatilization rate of gallium. The tailings gradually melt when the roasting temperature exceeds 900℃, resulting in a decrease in the chloridizing volatilization rate of gallium. The chloridizing volatilization rate of gallium reaches 78.86%at roasting temperature of 900℃ for 40 min, airflow of 0.1 m^(3)·h^(-1), and calcium content of 33.33 wt%. Study of the reaction kinetics of gallium in chlorination roasting shows that the values of activation energy both for chemically controlled anddiffusion-controlled reactionsare44.64and11.93 kJ·mol^(-1), respectively. This indicates that the chemical reaction serves an important function in the chlorination volatilization of gallium. Taken together, the results reveal the usefulness of tailings as a source of rare metals and provide a basis for gallium recovery and environmentally friendly disposal of copper tailings.

关键词： Copper tailings Gallium recovery Chlorination roasting Calcium chloride Kinetics

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Regarding the Distribution of Glue in the Pion

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Chinese Physics Letters 2021年第8期38卷 17-22页

作者： lei chang Craig D.Roberts School of Physics Nankai UniversityTianjin 300071China School of Physics Nanjing UniversityNanjing 210093China Institute for Nonperturbative Physics Nanjing UniversityNanjing 210093China

Understanding why the scale of emergent hadron mass is obvious in the proton but hidden in the pion may rest on mapping the distribution functions(DFs)of all partons within the pion and comparing them with those in the proton;and since glue provides binding in quantum chromodynamics,the glue DF could play a special *** reliable predictions for the proton’s DFs is difficult because the proton is a three-valence-body bound-state *** sketched herein,the situation for the pion,a two-valence-body problem,is much better,with continuum and lattice predictions for the valence-quark and glue DFs in *** beginning of theory alignment is timely because experimental facilities now either in operation or planning promise to realize the longstanding goal of providing pion targets,thereby enabling precision experimental tests of rigorous theory predictions concerning Nature’s most fundamental Nambu-Goldstone bosons.

关键词： valence thereby rigorous

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Corrosion Resistance of Superhydrophobic Mg-Al Layered Double Hydroxide Coatings on Aluminum Alloys

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Acta Metallurgica Sinica(English Letters) 2015年第11期28卷 1373-1381页

作者： Fen Zhang chang-lei Zhang Liang Song Rong-chang Zeng Lan-Yue Cui Hong-Zhi Cui College of Materials Science and Engineering Shandong University of Science and Technology State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and Technology Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences

A superhydrophobic surface was successfully constructed to modify the layered double hydroxide （LDH） coatings on aluminum alloy using stearic acid. The characteristics of the coatings were investigated using SEM, XRD, FT- IR and XPS. The corrosion resistance of the prepared coatings was studied using potentiodynamic polarization and electrochemical impedance spectrum. The results revealed that the superhydrophobic surface considerably improved the corrosion-resistant performance of the LDH coatings on the aluminum alloy substrate. The formation mechanism of the superhydrophobic surface was proposed.

关键词： Aluminum alloy Layered double hydroxide Superhydrophobic Stearic acid Corrosion

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Dynamics analysis of vibration process in Particle Impact Noise Detection

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第3期8卷 444-448页

作者： ZHANG Hui ZHOU chang-lei WANG Shu-juan ZHAI Guo-fu Department of Electrical Engineering Harbin Institute of Technology Harbin 150001 China Jining United Airline Company Jining 272000 China

Particle Impact Noise Detection (PIND) test is a reliability screening technique for hermetic device that is prescribed by MIL-PRF-39016E. Some test conditions are specified, although MIL-PRF-39016E did not specify how to obtain these condi- tions. This paper establishes the dynamics model of vibration process based on first order mass-spring system. The corresponding Simulink model is also established to simulate vibration process in optional input excitations. The response equations are derived in sinusoidal excitations and the required electromagnetic force waves are computed in order to obtain a given vibration and shock accelerations. Last, some simulation results are given.

关键词： Particle Impact Noise Detection (PIND) Vibration Electromagnetic force

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Pion parton distribution function in light-front holographic QCD

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Chinese Physics C 2020年第11期44卷 163-167页

作者： lei chang Khépani Raya Xiaobin Wang School of Physics Nankai UniversityTianjin 300071China

The valence-quark distribution function of the pion has been of interest for decades;particularly,the profile it should adopt when x→1(the large-x behavior)has been the subject of a long-standing *** the light-front holographic QCD(LFHQCD)approach,this behavior is controlled by the so-called reparametrization function,wτ(x),which is not fully determined from first *** show that,owing to the flexibility of wτ(x),the large-x profile u^π(x)∼(1−x)^2 can be contained within the LFHQCD *** is in contrast to a previous LFHQCD study(Guy *** Teramond et al.,***.,120(18),2018)in which u^π(x)∼(1−x)^1 was found *** our observations,augmented by perturbative QCD and recent lattice QCD results,we state that the large-x exponent of“2”cannot be excluded.

关键词： pion parton distribution function QCD

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Nanotechnology for the management of COVID-19 during the pandemic and in the post-pandemic era

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National Science Review 2022年第10期9卷 230-242页

作者： Chun Xu chang lei Sepanta Hosseinpour Saso Ivanovski Laurence J.Walsh Ali Khademhosseini School of Dentistry The University of Queensland Centre for Orofacial Regeneration Reconstruction and Rehabilitation (COR3) School of Dentistry The University of Queensland Australian Institute for Bioengineering and Nanotechnology The University of Queensland Terasaki Institute for Biomedical Innovation

Following the global COVID-19 pandemic,nanotechnology has been at the forefront of research efforts and enables the fast development of diagnostic tools,vaccines and antiviral treatment for this novel virus(SARS-CoV-2).In this review,we first summarize nanotechnology with regard to the detection of SARS-C oV-2,including nanoparticle-based techniques such as rapid antigen testing,and nanopore-based se quencing and sensing *** we investigate nanote chnology as it applies to the development of COVID-19 vaccines and anti-SARS-CoV-2 *** also highlight nanotechnology for the post-pandemic era,by providing tools for the battle with SARS-C oV-2 variants and for enhancing the global distribution of *** not only contributes to the management of the ongoing COVID-19 pandemic but also provides platforms for the prevention,rapid diagnosis,vaccines and antiviral drugs of possible future virus outbreaks.

关键词： COVID-19 nanotechnology SARS-CoV-2 diagnosis vaccines

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Illuminating the structure and dynamics of chromatin by fluorescence labeling

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Frontiers in Biology 2017年第4期12卷 241-257页

作者： Shipeng Shao lei chang Yingping Hou Yujie Sun State Key Laboratory of Membrane Biology Biodynamic Optical Imaging Center (BIOPIC) School of Life Sciences Peking UniversityBeijing 100871 China

BACKGROUND： Visualization of chromosomal loci location and dynamics is crucial for understanding many fundamental intra-nuclear processes such as DNA transcription, replication, and repair. OBJECTIVE： Here, we will describe the development of fluorescence labeling methods for chromatin imaging, including traditional as well as emerging chromatin labeling techniques in both fixed and live cells. We will also discuss current issues and provide a perspective on future developments and applications of the chromatin labeling technology. METHODS： A systematic literature search was performed using the PubMed. Studies published over the past 50 years were considered for review. More than 100 articles were cited in this review. RESULTS： Taking into account sensitivity, specificity, and spatiotemporal resolution, fluorescence labeling and imaging has been the most prevalent approach for chromatin visualization. Among all the fluorescent labeling tools, the adoption ofgenome editing tools, such as TALE and CRISPR, have great potential for the labeling and imaging of chromatin. CONCLUSION： Although a number of chromatin labeling techniques are available for both fixed and live cells, much more effort is still clearly required to develop fluorescence labeling methods capable of targeting arbitrary sequences non-intrusively to allow long-term, multiplexing, and high-throughput imaging of genomic loci and chromatin structures. The emerging technological advances will outline a next-generation effort toward the comprehensive delineation of chromatin at single-cell level with single-molecule resolution.

关键词： chromatin structure and dynamics FROS FISH TALE CRISPR/Cas9 single-guide RNA Suntag,super-resolution imaging

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