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Microstructure,phase composition and wear resistance of low valence electron concentration Al_(x)CoCrFeNiSi high-entropy alloys prepared by vacuum arc melting

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Journal of Iron and Steel Research International 2021年第2期28卷 181-189页

作者： Bing-qian Jin nan-nan zhang Yue zhang De-yuan Li Department of Material Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina Provincial Key Laboratory of Advanced Welding Technology and Automation Shenyang 110870LiaoningChina

The low valence electron concentration(VEC)Al_(x)CoCrFeNiSi(x=0.5,1.0,1.5 and 2.0)high-entropy alloys(HEAs)were designed by the fundamental properties of the constituent elements and prepared by vacuum arc melting *** effects of Al addition on the crystal structure and microstructure were *** microhardness and wear property were also *** results showed that the microstructure transformed from dendritic crystal to equiaxed *** was found that FCC phase gradually decreased with the increasing Al content and disappeared until in a composition of 1.0 in Al_(x)CoCrFeNiSi *** FCC phase was found with continuously adding Al,while the phase fraction of BCC increased from 85.0% to 91.8%,and VEC decreased from 7.00 to *** microhardness was increased gradually from 598 up to 909 HV with addition of Al from 0.5 to *** was the same of the compressive strength results,which improved from 1200 to 1920 *** wear coefficient and mass loss were in line with mechanical properties evolution,which was attributed to the microstructure transformation into equiaxed crystal and the increase in BCC phase.

关键词： High-entropy alloy Valence electron concentration Microstructure Phase assemblage Wear resistance

Effect of vanadium addition on microstructure and properties of AI_(0.5)Cr_(0.9)FeNi_(2.5)multi-principal alloys

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Journal of Iron and Steel Research International 2021年第5期28卷 586-596页

作者： De-xi Hao nan-nan zhang Yue zhang De-yuan Li Department of Material Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina Provincial Key Laboratory of Advanced Welding Technology and Automation Shenyang 110870LiaoningChina

AI_(0.5)Cr_(0.9)FeNi_(2.5)V_(x)(x=0,0.2,0.4,0.6,0.8,1.0)multi-principal alloys were prepared by vacuum arc *** effect of vanadium addition on its microstructure and properties was *** results show that the alloys of all components exhibited an FCC single-phase *** the addition of vanadium,the microstructure of the alloy changed from dendrites to equiaxed crystals,the grains were remarkably refined,and the layered CrV phase was exhibited,which improved the properties of the *** yield strength of the alloy was slightly improved,and the alloys with various components presented good *** V content reached 0.8,the yield strength was 600 MPa,and no fracture ***-wear testing showed that the wear debris was reduced with the addition of V *** sample with V element content of 0.4 had the best friction and wear *** surface grooves became shallow,the worn debris was less,and the wear mechanism was mainly abrasive *** polarisation curve showed that the alloy with V element content of 0.2 has the best corrosion *** passivation interval reached 900 *** corrosion potential and the corrosion current density were-496.299 mV and 2.759μA/cm^(2),respectively.

关键词： Multi-principal alloy Vacuum arc melting CrV phase Adhesive wear Electrochemical testing

Rational design of bimetallic catalysts for electrochemical CO_(2)reduction reaction:A review

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Science China Chemistry 2023年第5期66卷 1288-1317页

作者： Minhan Li Jia-nan zhang College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

The electrochemical CO_(2)reduction reaction(eCO_(2)RR)is a compelling approach to convert CO_(2)into high-value fuels and chemicals using renewable *** rational design of catalysts is of great importance for achieving outstanding performance of this ***-based catalysts have been drawing enormous attention in eCO_(2)RR due to their excellent catalytic performance and flexible *** the pursuit of overcoming the inherent disadvantages of monometallic catalysts and achieving breakthroughs in the catalytic performance,bimetallic strategy has been receiving extensive concerns and achieving remarkable results over *** this review,we attempt to give a comprehensive review on the bimetallic catalysts that are used for eCO_(2)*** effects in bimetallic catalysts that contribute to the enhanced eCO_(2)RR performance are first analyzed,demonstrating the superiority of bimetallic ***,the structural design of bimetallic catalysts is discussed as it plays a key role in eCO_(2)***,the current advances and rules of selectivity of bimetallic catalysts in eCO_(2)RR are summarized based on the selectivity *** reviewing efforts devoted in this field,this review is believed to present a timely overview of the progress of bimetallic eCO_(2)RR catalysts and to offer potential future directions in the aim of developing highly efficient catalysts for eCO_(2)RR.

关键词： electrochemical CO_(2)reduction bimetallic catalyst electronic effect tandem effect structural design

Black hole binaries and microquasars

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Frontiers of physics 2013年第6期8卷 630-660页

作者： Shuang-nan zhang Laboratory for Particle Astrophysics Institute of High Energy Physics Beijing 100049 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

This is a general review Oil the observations and physics of black hole X-ray binaries and microquasars, with the emphasize on recent developments in the high energy regime. The focus is put on understanding the accretion flows and measuring the parameters of black holes in them. It includes mainly two parts： i） Brief review of several recent review article on this subject; ii） Further development on several topics, including black hole spin measurements, hot accretion flows, corona formation, state transitions and thermal stability of standard think disk. This is thus not a regular bottom-up approach, which I feel not necessary at this stage. Major effort is made in making and incorporating from many sources useful plots and illustrations, in order to make this article more comprehensible to non-expert readers. In the end I attempt to make a unification scheme on the accretion-outflow （wind/jet） connections of all types of aecreting BHs of all accretion rates and all BH mass scales, and finally provide a brief outlook.

关键词： accretion and accretion disks neutron stars black holes jets and bursts X-ray sources γ-ray sources X-ray binaries

A super-high angular resolution principle for coded-mask X-ray imaging beyond the diffraction limit of a single pinhole

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Chinese Journal of Astronomy and Astrophysics 2009年第3期9卷 333-340页

作者： Chen zhang Shuang-nan zhang Department of Engineering Physics ＆ Center for Astrophysics Tsinghua University Beijing 100084 China Key Labora.tory of Particle Astrophysics Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100049 China Department of Physics ＆ Center for Astrophysics Tsinghua University Beijing 100084 China

High angular resolution X-ray imaging is always useful in astrophysics and solar physics. In principle, it can be performed by using coded-mask imaging with a very long mask-detector distance. Previously, the diffraction-interference effect was thought to degrade coded-mask imaging performance dramatically at the low energy end with its very long mask-detector distance. The diffraction-interference effect is described with numerical calculations, and the diffraction-interference cross correlation reconstruction method （DICC） is developed in order to overcome the imaging performance degradation. Based on the DICC, a super-high angular resolution principle （SHARP） for coded-mask X-ray imaging is proposed. The feasibility of coded mask imaging beyond the diffraction limit of a single pinhole is demonstrated with simulations. With the specification that the mask element size is 50 × 50 μm^2 and the mask-detector distance is 50 m, the achieved angular resolution is 0.32arcsec above about 10keV and 0.36arcsec at 1.24keV （λ = 1 nm）, where diffraction cannot be neglected. The on-axis source location accuracy is better than 0.02 arcsec. Potential applications for solar observations and wide-field X-ray monitors are also briefly discussed.

关键词： instrumentation high angular resolution - techniques image processing - telescopes

Development of the super high angular resolution principle for X-ray imaging

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Research in Astronomy and Astrophysics 2011年第1期11卷 119-124页

作者： Chen zhang Shuang-nan zhang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Department of Physics ＆ Center for Astrophysics Tsinghua University Beijing 100084 China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy ofSciences Beijing 100049 China

Development of the Super High Angular Resolution Principle （SHARP） for coded-mask X-ray imaging is presented. We prove that SHARP can be considered as a generalized coded mask imaging method with a coding pattern comprised of diffraction-interference fringes in the mask pattern. The angular resolution of SHARP can be improved by detecting the fringes more precisely than the mask＇s element size, i.e. by using a detector with a pixel size smaller than the mask＇s element size. The proposed mission SHARP-X for solar X-ray observations is also briefly discussed.

关键词： instrumentation: high angularresolution-- techniques: image processing-- telescopes

Personal Review:Research on ethanol synthesis from syngas

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 714-719页

作者： Jie HE Wen-nan zhang Qingdao Institute of Biomass Energy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266071 China

It is a very fine substitutable energy technology to synthesize ethanol from biomass-derived syngas. This paper summarized the development of preparing ethanol from syngas, and especially elaborated on the research status of catalysts for the process. Based on the relative researches on the reaction mechanism, structure and performance of the catalysts, the optimum design of catalysts with high activity was presented in this review, which set the theoretical and application foundation for the industrial production of ethanol from syngas.

关键词： Syngas Catalyst Ethanol Biomass Promoter

Internal dynamics of magma ocean and its linkage to atmospheres

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Acta Geochimica 2022年第4期41卷 568-591页

作者： Yizhuo zhang nan zhang Meng Tian Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing100871China Earth Dynamics Research Group School of Earth and Planetary SciencesCurtin UniversityBentley6102WAAustralia Center for Space and Habitability Universität BernGesellschaftsstrasse 63012BernSwitzerland

Geological and astronomical observations on the‘‘lava world’’of the rocky planet,with additional theoretical interpretation of Moon’s crustal formation,bring up to the occurrence of the magma ocean and lava ponds,which inherits accretion energy of rocky planetesimal and evolves with subsequent energy *** or global oceans of silicate melt could be a widespread lava phase after rocky planet accretion as well as large impact and could persist on planets on orbits around other stars for various time *** processes of magma ocean formation and solidification change the phases,cause element segregations,and strongly affect the earliest compositional differentiation and volatile content of the terrestrial *** form the starting point for cooling to mildly habitable conditions and for the onset of thermally driven solid-state mantle *** formation and crystallization of magma oceans also influence the assembly of a core,the origin of a crust,initiation of tectonics,and formation of an *** is inevitable to investigate the magma ocean dynamics of such an early period of Earth *** review focuses on the internal dynamics of magma oceans after planetesimal accretion and planetary formation including turbulence,particle motion,and solid-state convection,which determine the associated processes of cooling,crystallization,and convection of magma *** differentiation is discussed *** thermodynamics of equilibration between a magma ocean and an overlying,outgassed atmosphere is also discussed,highlighting the need for more data on volatile solubility in silicate *** effect of coupling between magma ocean and solid-state mantle convection is also discussed.

关键词： Magma ocean Early atmosphere Internal dynamics

An effective method to determine bedding system insulation based on measured data

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Building Simulation 2023年第1期16卷 121-132页

作者： nan zhang Bin Cao Yingxin Zhu Department of Building Science School of ArchitectureTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(Tsinghua University) Beijing 100084China Key Laboratory of Eco Planning&Green Building Ministry of Education(Tsinghua University)Beijing 100084China

The thermal environment is an essential factor that affects sleep *** many circumstances,the bed microenvironment is more important than the ambient environment because of the large covered area of the human body and the close contact between the bedding system and the human *** main objective of this research is to establish an effective method to determine bedding system insulation.A thermal manikin was used in the measurement of bedding system *** different types of quilts,which were filled with cotton,polyester and duvet respectively,were chosen to be *** total ten different quilts with different materials and weights were involved in the *** regular arrangements of covers were chosen with coverage rates of 94.1%,85.9%,70.6%,and 54.4%to test.A total of 64 bedding systems were tested to build an effective method to determine the bedding system *** the basis of test data,the change of bedding system insulation with coverage was found to be *** fitting was applied to establish an insulation evaluation method for bedding system *** addition,the effects of quilt cover and sleepwear on bedding system insulation were discussed and thermal insulation increment caused by quilt cover and sleepwear were *** relationships between neutral indoor temperature and weight per unit area of the quilt for different coverage rates have been quantified based on existing subject *** research provides an effective method to determine bedding system insulation,which can be widely used in thermal comfort research and HVAC system design.

关键词： sleep environment bedding system thermal insulation thermal comfort