期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
煅烧方式对草酸盐前驱体制备氧化锆性能的影响 被引量:3
1
作者 刘继进 陈宗璋 《中国有色金属学报》 EI CAS CSCD 北大核心 2004年第11期1833-1838,共6页
采用非线性加热法煅烧锆、钇的草酸盐前驱体,制备了8%Y2O3(摩尔分数)稳定ZrO2(8YSZ)超细粉末。研究了金属离子与草酸的摩尔比及热处理方法对8YSZ的晶体结构、晶粒大小、形貌、比表面积、粒子团聚的影响。通过改变不同温度范围的加热速... 采用非线性加热法煅烧锆、钇的草酸盐前驱体,制备了8%Y2O3(摩尔分数)稳定ZrO2(8YSZ)超细粉末。研究了金属离子与草酸的摩尔比及热处理方法对8YSZ的晶体结构、晶粒大小、形貌、比表面积、粒子团聚的影响。通过改变不同温度范围的加热速度来优化草酸盐前驱体热分解工艺。采用优化前驱体热分解工艺即非线性加热法,于600~700℃煅烧得到的粉末为等轴晶形,粒子大小在90~100nm之间,粒子间仅有较弱的软团聚。煅烧过程晶粒生长动力学的研究表明:当煅烧温度高于700℃时,晶粒生长的质量传输受晶粒扩散过程控制;低于700℃时,晶粒生长的质量传输由表面扩散过程控制。 展开更多
关键词 钇稳定氧化锆 非线性加热法 草酸盐前驱体 晶粒生长
下载PDF
Entropy generation applications in flow of viscoelastic nanofluid past a lubricated disk in presence of nonlinear thermal radiation and Joule heating
2
作者 Aamar Abbasi Waseh Farooq +4 位作者 M Ijaz Khan Sami Ullah Khan Yu-Ming Chu Zahid Hussain M Y Malik 《Communications in Theoretical Physics》 SCIE CAS CSCD 2021年第9期37-50,共14页
Entropy generation is the loss of energy in thermodynamical systems due to resistive forces,diffusion processes,radiation effects and chemical reactions.The main aim of this research is to address entropy generation d... Entropy generation is the loss of energy in thermodynamical systems due to resistive forces,diffusion processes,radiation effects and chemical reactions.The main aim of this research is to address entropy generation due to magnetic field,nonlinear thermal radiation,viscous dissipation,thermal diffusion and nonlinear chemical reaction in the transport of viscoelastic fluid in the vicinity of a stagnation point over a lubricated disk.The conservation laws of mass and momentum along with the first law of thermodynamics and Fick’s law are used to discuss the flow,heat and mass transfer,while the second law of thermodynamics is used to analyze the entropy and irreversibility.The numbers of independent variables in the modeled set of nonlinear partial differential equations are reduced using similarity variables and the resulting system is numerically approximated using the Keller box method.The effects of thermophoresis,Brownian motion and the magnetic parameter on temperature are presented for lubricated and rough disks.The local Nusselt and Sherwood numbers are documented for both linear and nonlinear thermal radiation and lubricated and rough disks.Graphical representations of the entropy generation number and Bejan number for various parameters are also shown for lubricated and rough disks.The concentration of nanoparticles at the lubricated surface reduces with the magnetic parameter and Brownian motion.The entropy generation declines for thermophoresis diffusion and Brownian motion when lubrication effects are dominant.It is concluded that both entropy generation and the magnitude of the Bejan number increase in the presence of slip.The current results present many applications in the lubrication phenomenon,heating processes,cooling of devices,thermal engineering,energy production,extrusion processes etc. 展开更多
关键词 entropy generation viscoelastic fluid lubricated surface nonlinear thermal radiation Joule heating Keller box method
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部