Piasecki M.,ugosz University |
Piasecki M.,Czestochowa University of Technology
Transactions of the Indian Ceramic Society | Year: 2012
Some effects induced by laser treatment in GeS2 glasses, glass-ceramics and selected chalcogenide crystals are presented. We show that thermal treatment of glasses or introducing controlled disorder in crystal lattice give the opportunity to make the desired changes in the optical and electrical properties of materials. Irradiation by CW and pulsed lasers can significantly change the absorbance and birefringence in the 400-800 nm spectral range. We have observed and measured changes of absorption and refractive index, and investigated relaxation process after switching off the irradiation. Chalcogenide crystals were promising for use in optically operated devices through their photoconductivity and efficient frequency doubling. Different possible mechanisms responsible for the effects are discussed. © 2012 Copyright The Indian Ceramic Society.
Jagan Mohini G.,Andhra Loyala College |
Sahaya Baskaran G.,Andhra Loyala College |
Ravi Kumar V.,Acharya Nagarjuna University |
Piasecki M.,ugosz University |
Veeraiah N.,Acharya Nagarjuna University
Materials science & engineering. C, Materials for biological applications | Year: 2015
Soda lime silica borate glasses mixed with different concentrations of TiO2 are synthesized by the melt-quenching technique. As a part of study on bioactivity of these glasses, the samples were immersed in simulated body fluid (SBF) solution for prolonged times (~21 days) during which weight loss along with pH measurements is carried out at specific intervals of time. The XRD and SEM analyses of post-immersed samples confirm the formation of crystalline hydroxyapatite layer (HA) on the surface of the samples. To assess the role of TiO2 on the formation of HA layer and degradability of the samples the spectroscopic studies viz. optical absorption and IR spectral studies on post- and pre-immersed samples have been carried out. The analysis of the results of degradability together with spectroscopic studies as a function of TiO2 concentration indicated that about 6.0 mol% of TiO2 is the optimal concentration for achieving better bioactivity of these glasses. The presence of the maximal concentration octahedral titanium ions in this glass that facilitates the formation of HA layer is found to be the reason for such a higher bioactivity. Copyright © 2015 Elsevier B.V. All rights reserved.
Berdowski J.,ugosz University |
Berdowska S.,Silesian University of Technology |
Aubry F.,University of Lorraine
Archives of Metallurgy and Materials | Year: 2013
The purpose of this paper was to investigate the physical and mechanical properties of compressed expanded graphite CEG and their porous derivatives after impregnation, polymerization; and carbonization by the use of acoustic emission method (AE). The mechanical and structural characteristics of compressed expanded graphite and their three groups of porous composites after each technological process are presented and discussed. The measurements of acoustic emission parameters in these materials were carried out at wide range of frequency of the waves (0.1÷F2.5 MHz). The changes of two of parameters: - AE pulses counts rate and spectrum distribution of AE waves - are presented in this paper. The analysis of the respective parameters AE also gives possibility to determine the micro- and macro structural changes of materials at different levels of technological processes. Applications of these materials as catalysts with high specific surface make them very interesting subject of study. Also compressed expanded graphite composite membranes prepared from furfuryl alcohol polymers are promising for gas separation.
Majchrowski A.,Military University of Technology |
Klosowicz S.,Military University of Technology |
Jaroszewicz L.R.,Military University of Technology |
Swirkowicz M.,Institute Of Electronic Materials Technology of Poland |
And 3 more authors.
Journal of Alloys and Compounds | Year: 2010
NdAl3(BO3)4 single crystals with different concentrations of Yb3+ were grown using the top seeded solution growth method. The absorption spectra of the grown samples were recorded at room temperature and analyzed using the standard Judd-Ofelt theory. Influence of Yb3+ concentration on the Nd3+ absorption properties was studied. Variation of the Nd3+ oscillator strengths with changing Yb3+ concentration suggests significant role of the Yb-Nd energy transfer in the formation of the absorption spectra. Following the absorption spectra we illuminated the investigated crystals at 532 nm absorption line to observe the changes of the two-photon absorption (TPA). We observed substantial increase of the TPA with the increased power of the illuminating laser which was proportional to the Yb content. © 2009 Elsevier B.V. All rights reserved.
Wojciechowski A.,Czestochowa University of Technology |
Ozga K.,Czestochowa University of Technology |
Reshak A.H.,University of South Bohemia |
Reshak A.H.,University Malaysia Perlis |
And 4 more authors.
Materials Letters | Year: 2010
An influence of the cw laser treatment at 660 nm (red), 532 nm (green) and 405 nm (blue) wavelengths on the absorption in l-alanine crystals was studied. We have established that increasing time of illumination for red laser wavelength leads to slight changes of absorption backgrounds without changes in the spectral features. The drastic changes are observed after illumination by green laser leading to occurrence of two clear and several less clear bands correlating well with increasing illumination time. Their intensities are only slightly dependent on time of optical treatment. The remaining part of the spectra demonstrates substantially less changes. Increasing optical SHG show clear correlation with the behavior of the red laser induced absorption. The effect demonstrates slow time decay. © 2010 Elsevier B.V.