Acoustic detection of laser induced melting of metals

control of the optical properties of nanoparticles by laser fields

در این پایان نامه، درهمتنیدگی بین یک سیستم نقطه کوانتومی دوگانه(مولکول نقطه کوانتومی) و میدان مورد مطالعه قرار گرفته است. از آنتروپی ون نیومن به عنوان ابزاری برای بررسی درهمتنیدگی بین اتم و میدان استفاده شده و تاثیر پارامترهای مختلف، نظیر تونل زنی(که توسط تغییر ولتاژ ایجاد می شود)، شدت میدان و نسبت دو گسیل خودبخودی بر رفتار درجه درهمتنیدگی سیستم بررسی شده اشت.با تغییر هر یک از این پارامترها، در...

Level Set Methods for Modeling Laser Melting of Metals

The physical model describing heat transfer and melting taking place during and after the interaction of a laser beam with a semi-infinite metal surface is based on the classical Stefan problem with appropriately chosen boundary conditions to reflect direct selective laser sintering of metals. A level set method for solving this problem is presented in this paper. From the results of these comp...

Nanoparticle-induced unusual melting and solidification behaviours of metals

Effective control of melting and solidification behaviours of materials is significant for numerous applications. It has been a long-standing challenge to increase the melted zone (MZ) depth while shrinking the heat-affected zone (HAZ) size during local melting and solidification of materials. In this paper, nanoparticle-induced unusual melting and solidification behaviours of metals are report...

Laser-induced thermal-acoustic velocimetry with heterodyne detection.

Laser-induced thermal acoustics (LITA) was used with heterodyne detection to measure simultaneously and in a single laser pulse the sound speed and flow velocity of NO>(2) -seeded air in a low-speed wind tunnel up to Mach number M =0.1 . The uncertainties of the velocity and the sound speed measurements were ~0.2 m/s and 0.5%, respectively. Measurements were obtained through a nonlinear least-s...

Laser-Induced Forward Transfer of Pure Metals