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Strongly nonlinear topological phases of cascaded topoelectrical circuits

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Frontiers of physics 2023年第3期18卷 51-58页

作者： Jijie Tang Fangyuan ma Feng Li Honglian Guo Di Zhou College of Science Minzu University of ChinaBeijing 100081China Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE)School of PhysicsBeijing Institute of TechnologyBeijing 100081China

Circuits provide ideal platforms of topological phases and matter,yet the study of topological circuits in the strongly nonlinear regime,has been *** propose and experimentally demonstrate strongly nonlinear topological phases and transitions in one-dimensional electrical circuits composed of nonlinear *** topological interface modes arise on domain walls of the circuit lattices,whose topological phases are controlled by the amplitudes of nonlinear voltage *** measured topological transition amplitudes are in good agreement with those derived from nonlinear topological band *** prototype paves the way towards flexible metamaterials with amplitude-controlled rich topological phases and is readily extendable to two and three-dimensional systems that allow novel applications.

关键词： strongly nonlinear Berry phase topological electrical

Study on the Catalytic Reforming Law of Solid-Phase Carbon and Nitrogen Sources Loaded with MnO_(2)at Low Temperatures in Tahe Heavy Oil

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China Petroleum Processing & Petrochemical Technology 2023年第4期25卷 52-60页

作者： Tan Dichen ma Zhaofei Peng Gaoyao Xiong Pan Yan Xuemin College of Chemistry and Environmental Engineering Yangtze UniversityJingzhouHubei 434023PR China

MnO_(2)/Melem composites were synthesized with MnO_(2)nanoparticles loaded onto the Melem using the hydrothermal *** raw materials for C and N carriers,Melem was prepared from melamine roasted at 354℃,and KMnO_(4)as a raw material for Mn,MnO_(2)nanoparticles were prepared using the hydrothermal synthesis of KMnO_(4).Scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and a laser particle size analyzer were used for structural characterization,and the catalytic oxidation performance of the heavy oil was investigated at different reaction temperatures(100℃to 180℃)using MnO_(2)/Melem with an oxidant and donor protonic *** results showed that the synthesizedβ-MnO_(2)nanoparticles were successfully loaded onto the Melem surface;the oil samples before and after the reaction at different temperatures were subjected to SARA analysis using Fourier transform infrared(FT-IR),elemental analysis,gas chromatography-mass spectrometry(GC-MS)and viscosity tests,*** was determined that the hydrocarbons in the crude oil were converted to heavy mass by oxidation reactions with the oxidant mainly through a low-temperature oxidation process below 140℃in the heavy oil when the temperature exceeds 140℃,in addition to the oxidation reaction with the oxidant,a cleavage reaction in the carbon chain occurs to form hydrocarbon substances with lower molecular weights.

关键词： heavy oil catalyst low-temperature catalytic oxidation in situ reforming

How economic globalization affects the happiness of residents in China——Empirical evidence from CGSS 2008

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China Finance and Economic Review 2016年第1期5卷 110-128页

作者： ma Bianjing Cai Haijing Zhejiang University of Finance and Economics China

This paper is a quantitative examination of the effect of economic globalization on Chinese citizens’happiness and its transmission mechanism based on China General Social Survey(CGSS)*** results show that economic globalization has enormously and indirectly promoted Chinese citizens’happiness by reducing inflation and unemployment,increasing income,improving health condition and narrowing the wealth *** conclusion is not affected by sample selection or self-selection bias,nor endogenous *** is suggested that as it promotes economic globalization,the Chinese government should try to mitigage its adverse impact by increasing expenditures on social security,health care,education,and vocational training,while making sure the benefits of economic globalization are shared by every social stratum.

关键词： economic globalization inflation unemployment happiness

Increasing Anthropogenic Mercury Pollution over the Last 200 Years Revealed by Lagoonal Sediments from Hainan Island,South China

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Chinese Geographical Science 2023年第6期33卷 1127-1140页

作者： LI Yanting XUE Jibin CHEN Jingqiang LU Yi ma Xinlu School of Geographical Sciences South China Normal UniversityGuangzhou510631China

The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last *** this study,we presented a high-resolution Hg deposition history between∼1780 and 2015 AD in a sediment core from Xincun Lagoon,located in the southeastern Hainan Island,South China,and analyzed it in conjunction with geochemical elements,grain-size distribution,organic matter,and HYSPLIT backward trajectory *** objective was to investigate the influencing factors affecting historical Hg deposition in relatively remote regions and assess the extent of the effects of natural background and human *** results showed that the Hg in the sediment was deposited primarily through atmospheric deposition,which was closely related to regional and even global human *** Hg contamination increased gradually from the 1830s to 1850s,possibly due to Hg emissions from Opium Wars I and II occurring in southeastern *** broad peaks of anthropogenic Hg were observed during the 1910s to 1950s and in the 1980s,likely associated with the two world wars and modern Chinese *** addition,a further sharp increase in anthropogenic Hg from the mid-1970s to the present occurred,likely originating from the intense industrial activities in China triggered by the reform and opening-up policy of China in 1978 and some countries in Southeast Asia.

关键词： Mercury deposition pollution history anthropogenic impact Xincun Lagoon Hainan,China

Simultaneously improving the strength and ductility of AZ91/GNPs composites through decorating graphene nanoplatelets with MgO

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Journal of materials Science & Technology 2024年第16期183卷 133-151页

作者： Pingbo Wang Jun Shen Tijun Chen Jiqiang ma Qinglin Li Shaokai Zheng State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of TechnologyLanzhou 730050China

magnesium matrix composites(MgMCs)have always suffered low strengthening efficiency and poor ductility due to the difficulties in pursuing the well-bonded ***,graphene nanoplatelets(GNPs)were decorated with magnesium oxide nanoparticles(MgO NPs)through chemical co-precipitation and then incorporated into AZ91 alloy to fabricate MgMCs via powder *** effect of MgO on the interface of the Mg/graphene system was investigated based on the first-principles calculations,and the result indicated that modifying GNPs with MgO NPs was helpful in improving the Mg-GNP interface *** interface structural analysis revealed that the MgO NPs were firmly bonded with both GNPs andα-Mg through the distortion area bonding and semi-coherent interfacial bonding,severing as a bridge to fasten the interface bonding of *** addition,the MgO NPs on GNPs acted as a barrier to prevent GNPs from seriously reacting with the AZ91 *** a result,the AZ91/MgO@GNPs composite was endowed with enhancements of 31%and 10%in the yield strength,and increments of 71%and 61%in elongation compared with the AZ91 alloy and AZ91/GNPs composite,respectively,exhibiting a more significant potential in optimizing the strength-toughness tradeoffcompared with the AZ91/***,the possible strengthening and toughening mechanisms were also discussed in *** work offers a relatively novel surface modification strategy to modulate the Mg-GNP interface for a simultane-ous improvement of strength and ductility.

关键词： Graphene nanoplatelets magnesium oxide First-principles calculations magnesium matrix composites Powder thixoforging

Characteristics and Influencing Factors of Microplastics in Snow in the Inner Mongolia Plateau, China

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Engineering 2024年第6期37卷 69-77页

作者： Hongwei Yu Junrong Shao Huawei Jia Diga Gang Baiwen ma Chengzhi Hu State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Changjiang Survey PlanningDesign and Research Co.Ltd.Wuhan 430010China

Microplastics(MPs;<5 mm)have become one of the most prominent global environmental pollution *** can spread to high altitudes through atmospheric transport and can be deposited by rainfall or snowfall,potentially thre... 详细信息

Microplastics(MPs;mate *** collected from surface snow in the Inner Mongolia Plateau,China,were used for quantitative analysis and *** results showed that MPs were easily detected,and the related concentration was approximately(68±10)–(199±22)MPsL1 in snow *** were the most common morphology,the polymer composition was largely varied,and the abundance and composition of MPs were linked to human activity to a great ***-throughput sequencing results showed that the composition and abundance of microorganisms also differed in snow samples from areas with different MP pollution characteristics,indicating a considerable difference in microbial functional *** may have an interference effect on the individual growth and functional expression of microorganisms in *** addition,the results showed that functional living areas(e.g.,landfills and suburban areas)in cities play an important role in the properties of *** instance,the highest abundance of MPs was found in thermal power plants,whereas the abundance of polymers per sample was significantly lower in the suburban *** MP contaminants hidden in snow can alter microbial structure and function and are therefore a potential threat to ecosystem health.

关键词： Human activities Snow Microplastics Microbial community Urban function Environmental effect

Roughness characterization and shearing dislocation failure for rock-backfill interface

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International Journal of Minerals,Metallurgy and materials 2024年第6期31卷 1167-1176页

作者： Meifeng Cai Zhilou Feng Qifeng Guo Xiong Yin Minghui ma Xun Xi Key Laboratory of High-Efficient Mine and Safety of Metal Mines of Ministry of Education Beijing 100083China Key Laboratory of Urban and Underground Space Engineering University of Science and Technology BeijingBeijing 100083China Shandong Gold Group Co LtdJinan 250102China

Shearing dislocation is a common failure type for rock–backfill interfaces because of backfill sedimentation and rock strata movement in backfill mining *** paper designed a test method for rock–backfill shearing *** digital image techno-logy and three-dimensional(3D)laser morphology scanning techniques,a set of 3D models with rough joint surfaces was ***,the mechanical behavior of rock–backfill shearing dislocation was investigated using a direct shear *** effects of interface roughness on the shear–displacement curve and failure characteristics of rock–backfill specimens were *** 3D fractal dimen-sion,profile line joint roughness coefficient(JRC),profile line two-dimensional fractal dimension,and the surface curvature of the frac-tures were *** correlation characterization of surface roughness was then analyzed,and the shear strength could be measured and calculated using *** results showed the following:there were three failure threshold value points in rock–backfill shearing dis-location:30%–50%displacement before the peak,70%–90%displacement before the peak,and 100%displacement before the peak to post-peak,which could be a sign for rock–backfill shearing dislocation *** surface JRC could be used to judge the rock–backfill shearing dislocation failure,including post-peak sliding,uniform variations,and gradient change,corresponding to rock–backfill disloca-tion failure on the field *** research reveals the damage mechanism for rock–backfill complexes based on the free joint surface,fills the gap of existing shearing theoretical systems for isomerism complexes,and provides a theoretical basis for the prevention and control of possible disasters in backfill mining.

关键词： rock–backfill roughness correlation characterization shearing dislocation interface failure

3D Interconnected Honeycomb‑Like Multifunctional Catalyst for Zn-Air Batteries

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Nano-Micro Letters 2023年第2期15卷 212-227页

作者： Tianxu Jin Junli Nie Mei Dong Binling Chen Jun Nie Guiping ma State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029People’s Republic of China College of Engineering Mathematics and Physical ScienceUniversity of ExeterExeter EX44QFUK

Developing high-performance and low-cost electrocatalysts is key to achieve the clean-energy ***,a dual regulation method is proposed to prepare a 3D honeycomb-like carbon-based catalyst with stable Fe/Co *** atoms are highly dispersed and fixed to the polymer microsphere,followed by a high-temperature decomposition,for the generation of carbon-based catalyst with a honeycomb-like *** as-prepared catalyst contains a large number of Fe/Co nanoparticles(Fe/Co NPs),providing the excellent catalytic activity and durability in oxygen reduction reaction,oxygen evolution reaction and hydrogen evolution *** Zn-air battery assembled by the as-prepared catalyst as air cathode shows a good charge and discharge capacity,and it exhibits an ultra-long service life by maintaining a stable charge and discharge platform for a 311-h *** X-ray absorption fine structure characterization and density functional theory calculation confirms that the Fe doping optimizes the intermediate adsorption process and electron transfer of Co.

关键词： Fe/Co nanoparticles Core-shell microspheres Multifunctional catalyst Stability

Option Pricing Based on Alternative Jump Size Distributions

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2016年第3期11卷 439-467页

作者： Jian Chen Chenghu ma School of Economics Xiamen University Xiamen 361005 China School of management Fudan University Shanghai 200433 China

It is well known that volatility smirks and heavy-tailed asset return distri- butions are two violations of the Black-Scholes model. This paper investigates the role of jump size distribution played in explaining these two abnormalities. We consider a jump-diffusion model with Laplace jump size distribution, in comparison to the con- ventional normal distribution. In addition, our analysis is built upon a pure exchange economy, in which the representative agent＇s risk preference shows a fanning charac- teristic. We find that, when a fanning effect is present, Laplace model produces a more remarkable leptokurtic pattern of the risk-neutral distribution implied by options, as well as generating more pronounced volatility smirks than the normal model.

关键词： general equilibrium recursive utility option pricing Laplace distribu-tion volatility smirk