@article{Szałajko20073636,
title = {The influence of light intensity on surface recombination in GaS single crystals},
author = {M. Szałajko and M. Nowak},
url = {http://www.sciencedirect.com/science/article/pii/S0169433206010361},
doi = {http://dx.doi.org/10.1016/j.apsusc.2006.07.073},
issn = {0169-4332},
year = {2007},
date = {2007-01-01},
journal = {Applied Surface Science},
volume = {253},
number = {7},
pages = {3636 - 3641},
abstract = {Gallium sulphide (GaS) is a layer structure semiconductor with relatively wide energy gap (Eg (295 K) = 2.5 eV and Eg (80 K) = 2.62 eV). It has potential applications in some areas of optoelectronics. This paper presents the investigations of the influence of light intensity on surface recombination velocity of charge carriers in GaS single crystals. To attain this purpose spectral dependences (between 420 and 550 nm) of absorption coefficients, reflectivity coefficients and photoconductivity were measured in vacuum. The investigations were performed for various light intensities in several temperatures from 80 to 333 K. The least square method was applied to fit the theoretical dependences of photoconductivity on wavelength and intensity of illumination at these temperatures. From the fittings the temperature and light intensity dependences of surface recombination velocity and bulk lifetime of charge carriers were obtained.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{0953-8984-19-19-196210,
title = {Quantum efficiency coefficient for photogeneration of carriers in gallium sulphide single crystals},
author = {M. Szałajko and M. Nowak},
url = {http://stacks.iop.org/0953-8984/19/i=19/a=196210},
doi = {10.1088/0953-8984/19/19/196210},
year = {2007},
date = {2007-01-01},
journal = {Journal of Physics: Condensed Matter},
volume = {19},
number = {19},
pages = {196210},
abstract = {This paper presents investigations of the quantum efficiency coefficient for the photogeneration of carriers in gallium sulphide (GaS) single crystals. Therefore the spectral dependences (between 420 and 550 nm) of photoconductivity (σ PC ) were measured for temperatures from 80 to 333 K and for different light intensities. Since σ PC depends on the absorption and reflection coefficients, these parameters were determined in the same range of temperatures. The least-squares method was applied to fit the experimental σ PC data with appropriate theoretical dependence. From this fitting, spectral dependences of quantum efficiency coefficients for different temperatures and different light intensities were obtained. A comparison of the values of absorption coefficient obtained from the measurements of optical transmittance and from evaluation of the quantum efficiency coefficient is presented.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Bodzenta2006617,
title = {Measurement of the thermal diffusivity of dental filling materials using modified Ångström's method},
author = {J. Bodzenta and B. Burak and M. Nowak and M. Pyka and M. Szałajko and M. Tanasiewicz},
url = {http://www.sciencedirect.com/science/article/pii/S010956410500237X},
doi = {http://dx.doi.org/10.1016/j.dental.2005.05.016},
issn = {0109-5641},
year = {2006},
date = {2006-01-01},
journal = {Dental Materials},
volume = {22},
number = {7},
pages = {617 - 621},
abstract = {Summary
Objectives
A new measuring technique for the determination of thermal diffusivity is proposed. Using this technique, the thermal properties of a few different dental filling materials were measured.

Methods
The proposed method for measurement of thermal diffusivity is based on the classical Ångström's method. The method exploits the propagation of a plane thermal wave generated by a Peltier's device in a cylindrical sample along its axis. The thermal diffusivity of the sample is calculated from the phase difference between harmonic components of temperatures measured at sample surfaces, perpendicular to the direction of thermal wave propagation. The estimated accuracy of measurement is typically about 10% for samples with low thermal diffusivity. The proposed method was used for the determination of thermal diffusivities of Achatit Bichromatic, Charisma and Dentimet dental filling materials.

Results
The measured thermal diffusivities were: 0.295(0.020)×10−6 m2 s−1 for Achatit Bichromatic, 0.321(0.015)×10−6 m2 s−1 for Charisma and 1.70(0.12)×10−6 m2 s−1 for Dentimet. The thermal conductivities of these materials were also estimated. The results were compared with values obtained from independent constant flux measurements with marble as a reference material.

Significance
There are no standard techniques for the determination of the thermal properties of dental filling materials. Moreover, it is difficult to find the thermal diffusivity and the thermal conductivity of many of them. The method proposed in this paper allows the simple and accurate measurement of thermal diffusivity. Thermal parameters of dental filling materials should be compatible with the parameters of human teeth. Lack of thermal compatibility can cause not only patient discomfort but also mechanical stresses leading to microcracks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}