研究透视:3D打印-钛合金|Science,在3D打印的金属合金中,通常存在粗大的柱状晶粒和不均匀分布的物相形成,这是不理想的状态,因为会形成不均匀和不高的力学性能。近日,澳大利亚昆士兰大学(The University of Queensland)ZHANG Jingqi等,...研究透视:3D打印-钛合金|Science,在3D打印的金属合金中,通常存在粗大的柱状晶粒和不均匀分布的物相形成,这是不理想的状态,因为会形成不均匀和不高的力学性能。近日,澳大利亚昆士兰大学(The University of Queensland)ZHANG Jingqi等,在Science上发文,报道了一种设计策略,可以直接从3D打印中释放一致和增强的力学属性。利用Ti-5Al-5Mo-5V-3Cr作为模型合金,研究发现,添加钼Mo纳米粒子,促进了凝固过程中的晶粒细化,并抑制了固态热循环过程中物相不均匀性的形成。由于双功能添加剂的微观结构变化,同时提升了均匀力学性能以及强度和延展性。展开更多
In order to explain the oscillation heat transfer dynamics of closed loop oscillation heat pipe (CLOHP) with two liquid slugs,analysis on the forces and heat transfer process of the partial gas-liquid phase system inv...In order to explain the oscillation heat transfer dynamics of closed loop oscillation heat pipe (CLOHP) with two liquid slugs,analysis on the forces and heat transfer process of the partial gas-liquid phase system involving multiple parameters was carried out,and a new type oscillation heat transfer dynamic model of the CLOHP was set up based on conservation laws of mass,momentum and energy.Application results indicate that its oscillation heat transfer dynamics features depend largely on the filling rate,pipe diameter and difference in temperature.Besides,oscillation intensity and transfer performance can be improved to a large extent by increasing the temperature difference properly and enlarging the pipe diameter within a certain range under a certain filling rate.展开更多
The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could bc useful in analyzing and optimizing the heat-work conversion systems. This work presents compa...The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could bc useful in analyzing and optimizing the heat-work conversion systems. This work presents comparative analyses of entransy and exergy for optimizations of heat-work conversion. The work production and heat transfer processes in Carnot cycle system are investigated with the formulations of exergy destruction, entransy loss, work entransy, entransy dissipation, and cfficiencics for both cases of dumping and non-dumping of used source fluid. The effects of source and condensation temperatures on the system performance arc systematically investigated for optimal condition of producing maximum work or work cntransy.展开更多
The electrochemical behaviors of battery chemistry,especially the operating voltage,are greatly affected by the complex electrode/electrolyte interface,but the corresponding basis understanding is still largely unclea...The electrochemical behaviors of battery chemistry,especially the operating voltage,are greatly affected by the complex electrode/electrolyte interface,but the corresponding basis understanding is still largely unclear.Herein,the concept of regulating electrode potential by interface thermodynamics is proposed,which guides the improvement of the energy density of Zn-MnO_(2) battery.A cationic electrolyte strategy is adopted to adjust the charge density of electrical double layer,as well as entropy change caused by desolvation,thus,achieving an output voltage of 1.6 V(vs.Zn^(2+)/Zn)and a capacity of 400 mAh g^(-1).The detailed energy storage behaviors are also analyzed in terms of crystal field and energy level splitting.Furthermore,the electrolyte optimization benefits the efficient operation of Zn-MnO_(2) battery by enabling a high energy density of 532 Wh kg^(-1) based on the mass of cathode and a long cyclic life of more than 500 cycles.This work provides a path for designing high-energy-density aqueous battery via electrolyte strategy,which is expected to be extended to other battery systems.展开更多
The performance in finite time of a quantum-mechanical Brayton engine cycle is discussed, without intro- duction of temperature. The engine model consists of two quantum isoenergetic and two quantum isobaric processes...The performance in finite time of a quantum-mechanical Brayton engine cycle is discussed, without intro- duction of temperature. The engine model consists of two quantum isoenergetic and two quantum isobaric processes, and works with a single particle in a harmonic trap. Directly employing the finite-time thermodynamics, the efficiency at maximum power output is determined. Extending the harmonic trap to a power-law trap, we find that the efficiency at max/mum power is independent of any parameter involved in the model, but depends on the confinement of the trapping potential.展开更多
文摘研究透视:3D打印-钛合金|Science,在3D打印的金属合金中,通常存在粗大的柱状晶粒和不均匀分布的物相形成,这是不理想的状态,因为会形成不均匀和不高的力学性能。近日,澳大利亚昆士兰大学(The University of Queensland)ZHANG Jingqi等,在Science上发文,报道了一种设计策略,可以直接从3D打印中释放一致和增强的力学属性。利用Ti-5Al-5Mo-5V-3Cr作为模型合金,研究发现,添加钼Mo纳米粒子,促进了凝固过程中的晶粒细化,并抑制了固态热循环过程中物相不均匀性的形成。由于双功能添加剂的微观结构变化,同时提升了均匀力学性能以及强度和延展性。
基金Project(531107040300)supported by the Fundamental Research Funds for the Central Universities in ChinaProject(51176045)supported by the National Natural Science Foundation of China
文摘In order to explain the oscillation heat transfer dynamics of closed loop oscillation heat pipe (CLOHP) with two liquid slugs,analysis on the forces and heat transfer process of the partial gas-liquid phase system involving multiple parameters was carried out,and a new type oscillation heat transfer dynamic model of the CLOHP was set up based on conservation laws of mass,momentum and energy.Application results indicate that its oscillation heat transfer dynamics features depend largely on the filling rate,pipe diameter and difference in temperature.Besides,oscillation intensity and transfer performance can be improved to a large extent by increasing the temperature difference properly and enlarging the pipe diameter within a certain range under a certain filling rate.
基金supported by the Research Fund,Kumoh National Institute of Technology
文摘The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could bc useful in analyzing and optimizing the heat-work conversion systems. This work presents comparative analyses of entransy and exergy for optimizations of heat-work conversion. The work production and heat transfer processes in Carnot cycle system are investigated with the formulations of exergy destruction, entransy loss, work entransy, entransy dissipation, and cfficiencics for both cases of dumping and non-dumping of used source fluid. The effects of source and condensation temperatures on the system performance arc systematically investigated for optimal condition of producing maximum work or work cntransy.
基金supported by the National Natural Science Foundation of China(52072411,51932011)the Natural Science Foundation of Hunan Province(2021JJ20060)the Fundamental Research Funds for the Central Universities of Central South University(2021zzts0093)。
文摘The electrochemical behaviors of battery chemistry,especially the operating voltage,are greatly affected by the complex electrode/electrolyte interface,but the corresponding basis understanding is still largely unclear.Herein,the concept of regulating electrode potential by interface thermodynamics is proposed,which guides the improvement of the energy density of Zn-MnO_(2) battery.A cationic electrolyte strategy is adopted to adjust the charge density of electrical double layer,as well as entropy change caused by desolvation,thus,achieving an output voltage of 1.6 V(vs.Zn^(2+)/Zn)and a capacity of 400 mAh g^(-1).The detailed energy storage behaviors are also analyzed in terms of crystal field and energy level splitting.Furthermore,the electrolyte optimization benefits the efficient operation of Zn-MnO_(2) battery by enabling a high energy density of 532 Wh kg^(-1) based on the mass of cathode and a long cyclic life of more than 500 cycles.This work provides a path for designing high-energy-density aqueous battery via electrolyte strategy,which is expected to be extended to other battery systems.
基金Supported by the National Natural Science Foundation of China under Grant No. 11265010, the Jiangxi Provincial Natural Science Foundation under Grant No. 20132BAB212009, University Young Teacher Training Program of the SMEC under Grant No. egdll005, and by Innovation Program of the SMEC under Grant No. 12YZ177
文摘The performance in finite time of a quantum-mechanical Brayton engine cycle is discussed, without intro- duction of temperature. The engine model consists of two quantum isoenergetic and two quantum isobaric processes, and works with a single particle in a harmonic trap. Directly employing the finite-time thermodynamics, the efficiency at maximum power output is determined. Extending the harmonic trap to a power-law trap, we find that the efficiency at max/mum power is independent of any parameter involved in the model, but depends on the confinement of the trapping potential.
