Defect formation is a critical challenge for powder-based metal additive manufacturing(AM).Current understanding on the three important issues including formation mechanism,influence and control method of metal AM def...
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Defect formation is a critical challenge for powder-based metal additive manufacturing(AM).Current understanding on the three important issues including formation mechanism,influence and control method of metal AM defects should be *** this review paper,multi-scale defects in AMed metals and alloys are identified and for the first time classified into three categories,including geometry related,surface integrity related and microstructural *** particular,the microstructural defects are further divided into internal cracks and pores,textured columnar grains,compositional defects and dislocation *** root causes of the multi-scale defects are *** key factors that affect the defect formation are identified and *** detection methods and modeling of the multi-scale defects are briefly *** effects of the multi-scale defects on the mechanical properties especially for tensile properties and fatigue performance of AMed metallic components are *** control and mitigation methods for the corresponding defects,include process parameter control,post processing,alloy design and hybrid AM techniques,are summarized and *** research aspect,current research gaps and future prospects from three important aspects of the multi-scale AM defects are identified and delineated.
Based on the review of latest papers related to the application of barium alloy, the deoxidization effects of barium and barium alloy, and the dynamic characteristics of molten bath have been systematically studied by...
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Based on the review of latest papers related to the application of barium alloy, the deoxidization effects of barium and barium alloy, and the dynamic characteristics of molten bath have been systematically studied by means of the convection free bath, natural convection bath, air and vacuum induction melting experiments. It was found that both the total oxygen content and soluble oxygen content in molten bath decreased rapidly. The results obtained provided practical and theoretical basis for further synthetic applications of barium alloy in metallurgical industry.
The effects of Mg on the inclusion characteristics of 35CrNi3MoV steel have been studied. The results show that Mg treatment reduces obviously the amount of inclusion in the steel. Magnesium and oxygen in liquid steel...
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The effects of Mg on the inclusion characteristics of 35CrNi3MoV steel have been studied. The results show that Mg treatment reduces obviously the amount of inclusion in the steel. Magnesium and oxygen in liquid steel form dispersed fine particles of MgO, to which other oxides or sulphides nucleated at heterogeneity and grown during solidification. In this way the inclusions are modified. The small spherical inclusions containing MgO have been observed in the Mg treated steel in contrast to the large angular inclusions with Al2O3 in the conventional steel. Especially the elongated MnS inclusion is replaced by small MgS . MgO or MgS. MnS . MgO complex inclusion. The formation of inclusions have been discussed.
Analytical studies on electromagnetoelastic behaviors are presented for the functionally graded piezoelectric material （FGPM） solid cylinder and sphere placed in a uniform magnetic field and subjected to the externa...
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Analytical studies on electromagnetoelastic behaviors are presented for the functionally graded piezoelectric material （FGPM） solid cylinder and sphere placed in a uniform magnetic field and subjected to the external pressure and electric loading. When the mechanical, electric and magnetic properties of the material obey an identical power law in the radial direction, the exact displacements, stresses, electric potentials and perturbations of magnetic field vector in the FGPM solid cylinder and sphere are obtained by using the infinitesimal theory of electromagnetoelasticity. Numerical examples also show the significant influence of material inhomogeneity. It is interesting to note that selecting a specific value of inhomogeneity parameter β can optimize the electromagnetoelastic responses, which will be of particular importance in modern engineering designs.
作者：
Y.T. He F. Li G.Q. Zhang L.j. Ernst X.j. fuCollege of Aeronautics
University of Air Force Engineering Xi''an 710038 China College of Aeronautics
Northwestern Polytechnical University Xi''an710072 China College of Aeronautics University of Air Force Engineering Xi''an 710038 China Philips Centre for Industrial Technology P.O.Box 218 5600 MD Eindhoven The Netherlands Delft University of Technology 2628 CD Delft The Netherlands College of Aeronautics Northwestern Polytechnical University Xi''an 710072 China
Fracture toughness is very important when applying Damage Tolerance Design and Assessment Techniques. The traditional testing approach for obtaining fracture toughness values is costly and time consuming. In order to ...
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Fracture toughness is very important when applying Damage Tolerance Design and Assessment Techniques. The traditional testing approach for obtaining fracture toughness values is costly and time consuming. In order to estimate the fracture toughness of ductile metals, the fracture mechanics theory, materials plastic deformation theory and materials constructive relationships are employed here. A series of formulae and a theoretical approach are presented to calculate fracture toughness values of different materials in the plane stress and plane strain conditions. Compared with test results, evaluated values have a good agreement.
In this paper,we study the symmetry energy and the Wigner energy in the binding energy formula for atomic *** simultaneously extract the I2 symmetry energy and Wigner energy coefficients using the double difference of...
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In this paper,we study the symmetry energy and the Wigner energy in the binding energy formula for atomic *** simultaneously extract the I2 symmetry energy and Wigner energy coefficients using the double difference of "experimental" symmetry-Wigner energies,based on the binding energy data of nuclei with A≥*** study of the triple difference formula and the "experimental" symmetry-Wigner energy suggests that the macroscopic isospin dependence of binding energies is explained well by the I2 symmetry energy and the Wigner energy,and further consideration of the I4 term in the binding energy formula does not substantially improve the calculation result.
Data Assimilation(DA) plays a crucial role in modern numerical forecasting(Kalnay, 2002). It has been demonstrated that incorporating real-time observational data into forecast models significantly enhances the accura...
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Data Assimilation(DA) plays a crucial role in modern numerical forecasting(Kalnay, 2002). It has been demonstrated that incorporating real-time observational data into forecast models significantly enhances the accuracy of both shortterm weather forecasts(Bauer et al., 2015;Bannister, 2017)and long-term climate predictions(Karspeck et al., 2013;Mochizuki et al., 2016).
Nonadiabatic holonomic quantum computers serve as the physical platform for nonadiabatic holonomic quantum *** quantum computation has entered the noisy intermediate-scale era,building accurate intermediate-scale nona...
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Nonadiabatic holonomic quantum computers serve as the physical platform for nonadiabatic holonomic quantum *** quantum computation has entered the noisy intermediate-scale era,building accurate intermediate-scale nonadiabatic holo-nomic quantum computers is clearly *** that measurements are the sole means of extracting information,they play an indispensable role in nonadiabatic holonomic quantum ***,developing methods to reduce measurement errors in nonadiabatic holonomic quantum computers is of great ***,while much attention has been given to the research on nonadiabatic holonomic gates,the research on reducing measurement errors in nonadiabatic holonomic quantum computers is severely *** this study,we propose a measurement error reduction method tailored for intermediate-scale nonadiabatic holonomic quantum *** reason we say this is because our method can not only reduce the measurement errors in the computer but also be useful in mitigating errors originating from nonadiabatic holonomic *** these features,our method significantly advances the construction of accurate intermediate-scale nonadiabatic holonomic quantum computers.
1 Introduction Recently there had considerable interest in Li4Ti5O12 as a potential anode for use in Li-ion batteries. Usually, it was used as an anode combined with a high voltage cathode[1-5]. It has many advantages...
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1 Introduction Recently there had considerable interest in Li4Ti5O12 as a potential anode for use in Li-ion batteries. Usually, it was used as an anode combined with a high voltage cathode[1-5]. It has many advantages compared to the currently used graphite. For example, it presents virtually unlimited cycle life due to zero strain or volume change when lithium intercalates into and de-intercalates from[6]. Generally, Li4Ti5O12 was prepared by a solid-state reaction from stoichiometric amounts of Li2CO3...
The Earth's magnetosphere is a region occupied by many artificial satellites, and also is a region that spacecraft must cruise during the deep-space exploration. In this sense, the Earth's magnetosphere is closely rel...
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The Earth's magnetosphere is a region occupied by many artificial satellites, and also is a region that spacecraft must cruise during the deep-space exploration. In this sense, the Earth's magnetosphere is closely related to human activity and is a candidate for us to expand our living space. Generally, the Earth's magnetosphere can preclude most energetic particles from the Sun and the interstellar space, effectively protecting human beings on the Earth from being attacked and thus making the Earth to be a habitable planet. However, in some conditions, the Earth's magnetosphere becomes dynamic and energetic, and consequently may damage the artificial satellites, threaten the astronauts' health, and disrupt the ground infrastructure, which leads to a decline in the national economy. Therefore, investigating how energy is injected into the magnetosphere, how it is transported in the magnetosphere, and how it is ultimately dissipated in the magnetosphere are the key issues in space physics. Targeting these key issues, in this paper, we review the recent progress on them. Particularly, we introduce the relevant scientific questions,models, methods, and spacecraft missions, for better building a physical link among the energy injection, transport, and dissipation in the magnetosphere, present an energy chain of the magnetosphere, reveal the relationship between such energy chain and the space weather events, and discuss the forecasting and warning methods for energetic-particle events in the magnetosphere. The magnetospheric energy chain discussed in this paper will help us reveal the mechanisms of space weather events, establish the models of space environment, and forecast the disastrous space weather events.
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