Photoreflectance (PR) spectra are measured at room temperature for energies in the vicinity of the E0 critical point for doped GaAs/SI‐GaAs structures. In the analysis of the obtained spectra the assumption that the PR signal is created due to the internal electric field in both surface and interface regions is verified. In the calculation procedure dispersion relations (Kramers‐Kronig analysis) are used for the PR spectra of heavily doped epilayers. In this case the possibility of very precise surface‐interface distance determination is suggested.
In accordance with the requirements of PN EN 13201-5 standard for road lighting installation, energy performance indicators should be descripted. In order to calculate energy performance indicators, it is necessary to know the active power of the road lighting system. The above standard does not specify whether active power losses should be taken into account in calculations. The main purpose of the article is to estimate the active power losses in the road lighting installation. The article presents methods for calculating active power losses, taking into account losses in all main elements of the installation. The obtained calculation results show the relationship between active power losses and the power of luminaires, their number and spacing between poles. Calculations of active power losses were made for single-phase and three-phase installations. The active power losses in a three-phase system do not exceed 1.5% and in a single-phase installation they may be greater than 7%. Therefore, in order to obtain exact values of energy performance indicators (and also predict electricity consumption), active power losses should be taken into account in calculations. In addition, a comparative analysis of the effect of luminaires dimming and active power losses on annual CO2 emissions was made. Not taking into account the active power losses in the calculation of the lighting installation’s power, for single-phase installations in particular, understates the calculated value of CO2 emissions by more than 6%.
The paper presents the results of laboratory tests concerning the measurements of electrical parameters of road lighting luminaires. These measurements were focused on determining the dependence of the electrical parameters of the luminaires versus the changes of the RMS (Root Mean Square) value of the supply voltage and the level of disturbances in the supply voltage. The basic electrical parameters for light-emitting diode (LED) luminaires were analysed with the option of luminous flux adjustment if it existed. During the laboratory measurements, the luminaires were powered from the Agilent 6834B distorted voltage generator within the assumed acceptable range of the changes in the deformation level resulting from the applicable legal provisions for the reproduction of actual power supply conditions.
The photoreflectance spectra for heavily doped p-type GaAs/SI-GaAs structures have been measured at room temperature for the energies in the vicinity of the GaAs band gap. The complex photoreflectance function is defined and determined by means of a Kramers–Krönig analysis from the measured photoreflectance spectra. The modulus of the complex photoreflectance function gives us the critical point energy whereas the phase of this function can be used for a topographical study of the homogeneity of the internal electric field in the structure.
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