(Digital Presentation) Adsorption Characteristics of SiO2/Si, Nanocomposites of Multiwalled Carbon Nanotubes and Polyamide, Polyvinyl Chloride, Polyethylene, Porous Polystyrene

Abstract

Kyiv national university, Kyiv-01601, Ukraineonanko@i.ua : In this work nondestructive method, which is allow to determine from internal friction difference ΔQ-1/Q-1 0 of elastic vibrations structure defects density Nd and the depth of broken layer hb, is offered for SiO2/Si wafer-plates. Outcomes of the evaluation of dynamic characteristics interstitial atoms, vacancy and O-complexes can be applied for account of a condition of an annealing with the purpose of deriving specific structural defects in SiO2/Si wafer-plates. Introduction The leading factor of the elastic anisotropy forming is a crystallography orientation and the orientation of grains on the form with the orientation of miсrocracks, pores [1]. Acoustic emission (AE) allow to receive the additional information about the process of miсrocracks [2]. A non-destructive method for the technological control of the structure defects by measuring internal friction (IF) and elastic modulus E after laser radiation was developed. Experimental procedure The study of influence of structure defects on damping of vibrations in Si/SiO2 plates by the diameter of D = 100÷60 mm and by the thickness of hSiO2 ≈ 600 nm, hSi ≈ 470 000 nm, allows to estimate the degree of perfection of crystalline structure. Brief thermal influence is created by the powerful impulsive nanosecond neodymium laser resulted to local surface tissue fusion. After stopping of the laser radiation action of fusion solidification begun exactly from the surface, but the crater underbody is extended (molten) and created the additional squeezing mechanical tension σi, that „pull” the central part of crater surface in depth with the liquid crater fusion.The pressure dynamics Рi(t) is following: at the beginning of destruction Рi grows quickly, and on the completion of impulse action diminishes instantly on the value of the light pressure created by the laser. Then the diminishing pressure Рi becomes slower, for nanosecond times of laser influence the appearance of acoustic emission (AE) review is important in time range τ ≈ 0.2 nanosec [3,4]. Results and discussion Effects of AE after nanosecond neodymium and ruby laser irradiation in fluid SiO2 are investigated. The fusion depth as the result of relaxation of photothermal elastic strains Ϭi at the large time ∂T/∂t = (55±100).109 K/sec and spatial ∂T/∂x = (1±2).104 K/sm temperature gradients on the SiO2 surface was appraised Δh ≈ 10000 nm. The quantity of reflections N = τ/t ≈ 0.2 nsec/0.02 nsec = 10, approximately 10 times forward-back in specimen. There was a small value of IF background in SiO2 Qo -1 ≈ 2.10-6 to T ≈ 385 K. AE method was measured the group longitudinal wave velocity in fluid SiO2 by water solution of NaCl with the concentration ρ ≈ 38.125 g/l there was v║ = l/τ » 0.03032 m/10.7 mcsec » 2830 m/sec; shear wave velocity v┴ » 2300 m/sec. Oscilloscopegramma of impulses with transversal polarization, which are reflected in SiO2/Si wafer-plate is represented in Figure 1. Figure 1. Oscilloscopegramma of impulses with transversal polarization, which are reflected in SiO2/Si wafer-plate.Taking into account the value of density ρ ≈ 2.63.103 kg/m3, shear modulus G = ρ.v┴ 2 » 13.91 GPa and elastic modulus E = ρ.v║ 2 » 21.06 GPa were determined. Conclusions The value of internal friction background Q-1 0 after temperature, mechanical treatments describes the changes of the elastic stress σi fields in SiO2/Si wafer-plate after laser radiation.After laser radiation outcomes of the evaluation of dynamic characteristics interstitial atoms Sij, vacancy V and O-complexes can be applied for account of a condition of an annealing with the purpose of deriving specific structural defects in SiO2/Si. Acknowledgements This work has been supported by Ministry of Education and Science of Ukraine: Grant of the Ministry of Education and Science of Ukraine for perspective development of a scientific direction "Mathematical sciences and natural sciences" at Taras Shevchenko National University of Kyiv.