The refractive index is one of the important parameters describing the optical properties of solid materials. However, it is difficult to obtain a quantitative relation between the refractive index and the structure a...The refractive index is one of the important parameters describing the optical properties of solid materials. However, it is difficult to obtain a quantitative relation between the refractive index and the structure and composition of materials. A qualitative relation between the refractive index and some atomic parameters of materials was proposed and demonstrated by some oxide optical crystals. A parameter P=r~-/F=r~-/(r~+ΔxD) is defined, in which Δx is the difference of the electronegativities between cations and anions in the materials and r~+ and r~- are the radii of cations and anions respectively. On the other hand, the factor D was introduced to describe the effect of mass difference of the ions. It is demonstrated by both theoretical discussion and experimental data that refractive index is a decreasing function of parameter P. The relation may be useful for the investigation of optical materials.展开更多
紧耦合气雾化技术(Close-coupled gas atomization,CCGA)具有雾化效率高,粉末球形度好,综合生产成本低等优势,现已成为当前3D打印用金属粉末制备的主流技术之一。为进一步提升紧耦合气雾化的雾化效率,提升细粉收得率,促进3D打印产业的...紧耦合气雾化技术(Close-coupled gas atomization,CCGA)具有雾化效率高,粉末球形度好,综合生产成本低等优势,现已成为当前3D打印用金属粉末制备的主流技术之一。为进一步提升紧耦合气雾化的雾化效率,提升细粉收得率,促进3D打印产业的快速发展,对紧耦合气雾化的研究成为金属粉末制备领域的热点之一。近年来,研究者们开始使用高速摄影和粒子图像测速技术直观真实地观察到了气雾化过程中熔体破碎的细节,也为数值模拟得到的结果提供了实验验证,进一步揭示气雾化流场机制。同时,随着计算机运算能力的迅速发展和粉末形成理论模型的不断优化,将计算流体力学(Computational Fluid Dynamics,CFD)的数值模拟技术应用于对气雾化的研究得到广泛关注,研究者们对雾化流场结构和粉末粒径分布取得的研究成果极大促进了对气雾化流场机制的认识。高速摄影技术和数值模拟相辅相成,为气雾化实际生产中提高雾化效率提供了十分可靠的理论指导。因此,简述了基于图像观察和数值模拟的紧耦合气雾化的研究进展,归纳了两种方法在流场结构和雾化机制研究方面的应用,总结了两种方法用于指导雾化工艺参数优化及喷盘结构参数设计实践的进展。展开更多
文摘The refractive index is one of the important parameters describing the optical properties of solid materials. However, it is difficult to obtain a quantitative relation between the refractive index and the structure and composition of materials. A qualitative relation between the refractive index and some atomic parameters of materials was proposed and demonstrated by some oxide optical crystals. A parameter P=r~-/F=r~-/(r~+ΔxD) is defined, in which Δx is the difference of the electronegativities between cations and anions in the materials and r~+ and r~- are the radii of cations and anions respectively. On the other hand, the factor D was introduced to describe the effect of mass difference of the ions. It is demonstrated by both theoretical discussion and experimental data that refractive index is a decreasing function of parameter P. The relation may be useful for the investigation of optical materials.
文摘紧耦合气雾化技术(Close-coupled gas atomization,CCGA)具有雾化效率高,粉末球形度好,综合生产成本低等优势,现已成为当前3D打印用金属粉末制备的主流技术之一。为进一步提升紧耦合气雾化的雾化效率,提升细粉收得率,促进3D打印产业的快速发展,对紧耦合气雾化的研究成为金属粉末制备领域的热点之一。近年来,研究者们开始使用高速摄影和粒子图像测速技术直观真实地观察到了气雾化过程中熔体破碎的细节,也为数值模拟得到的结果提供了实验验证,进一步揭示气雾化流场机制。同时,随着计算机运算能力的迅速发展和粉末形成理论模型的不断优化,将计算流体力学(Computational Fluid Dynamics,CFD)的数值模拟技术应用于对气雾化的研究得到广泛关注,研究者们对雾化流场结构和粉末粒径分布取得的研究成果极大促进了对气雾化流场机制的认识。高速摄影技术和数值模拟相辅相成,为气雾化实际生产中提高雾化效率提供了十分可靠的理论指导。因此,简述了基于图像观察和数值模拟的紧耦合气雾化的研究进展,归纳了两种方法在流场结构和雾化机制研究方面的应用,总结了两种方法用于指导雾化工艺参数优化及喷盘结构参数设计实践的进展。
