The Luminescence of Laser-Produced Carbon Nanodots: The Effect of Aggregation in PEI Solution.

Carbon nanodots (CNDs) produced in pure water by the ablation of graphite with a nanosecond laser pulse exhibit weak photoluminescence. A small addition of polyethyleneimine (PEI) to the aqueous suspension of CNDs causes a significant increase in emissions. This paper presents experimental and theoretical studies of the emission properties of CND/PEI systems.

Mechanical and Thermal Properties of W-Ta-B Coatings Deposited by High-Power Impulse Magnetron Sputtering (HiPIMS).

We present the deposition and characterization of tungsten-tantalum diboride (W,Ta)B coatings prepared by the high-power impulse magnetron sputtering technique. We evaluated the influence of pulse duration and substrate bias on the properties of (W,Ta)B films. A high hardness of up to 35 GPa measured by nanoindentation was simultaneously obtained with good elastic properties.

Temporal Evolution of Pressure Generated by a Nanosecond Laser Pulse Used for Assessment of Adhesive Strength of the Tungsten-Zirconium-Borides Coatings.

The article presents theoretical and experimental study of shock waves induced by a nanosecond laser pulse. Generation of surface plasma pressure by ablation of the graphite absorption layer in water medium and shock wave formation were analyzed theoretically and experimentally. The amplitude and temporal variation of the shock wave pressure was determined basing on a proposed hydrodynamic model of nanosecond laser ablation and experimentally verified with use of a polyvinylidene fluoride (PVDF) piezoelectric-film sensor.

Improved Laser Ablation Method for the Production of Luminescent Carbon Particles in Liquids.

An improved method for the production of luminescent carbon nanoparticles is proposed in this work. The new method overcomes the disadvantages of commonly used approaches. It involves two-stage laser ablation in water and in aqueous solutions, where the first stage is the laser ablation of a graphite target and the second is the shredding of particles produced in the first step.

Luminescent Carbon Dots Synthesized by the Laser Ablation of Graphite in Polyethylenimine and Ethylenediamine.

Fluorescent carbon dots (CDs) synthesized by pulsed laser ablation in liquid (PLAL) are still interesting materials due to their possible applications. However, unlike CDs produced by the hydrothermal method, CDs produced the synthesis products by the PLAL method were never separated by dialysis, which differentiates the synthesis products and allows the identification of the main source of fluorescence. In this work, the synthesis of fluorescent carbon dots (CDs) was performed by nanosecond laser ablation of a graphite target immersed in polyethyleneimine (PEI) and ethylenediamine (EDA), and the synthesis products were separated by dialysis.

New Zirconium Diboride Polymorphs-First-Principles Calculations.

Two new hypothetical zirconium diboride (ZrB 2 ) polymorphs: (-P6 3 /mmc-space group, no. 194) and (-Pmmn-space group, no. 59), were thoroughly studied under the first-principles density functional theory calculations from the structural, mechanical and thermodynamic properties point of view.