Influence of a Jump in the Power of Laser Radiation on Its Measurement

Simulation and investigation of the effect of an isolated jump on realization of the unit of power of laser radiation and dissemination of the size of the unit are considered. Results are obtained by means of a newly developed algorithm that characterizes the behavior of the mean value of a signal and the standard deviation of a system as functions of the parameters of a jump in the power of laser radiation and the length and amplitude of the jump. If information concerning the time when a jump occurs is available, the proposed algorithm makes it possible to take into account how a jump affects the ultimate result of a measurement.     

Mathematical Simulation of Radiation Instability and a Possible Method of Taking Instability into Account in Realization of the Unit of Power of Laser Radiation and Dissemination of the Unit of Power

The present study is devoted to mathematical simulation of the instability of laser radiation. An algorithm for establishing the shape of continuous laser radiation received at the input of a measuring system is presented.     

Simulation of the detection of underwater objects from air

Simulation modelling of the detection through a water-air boundary of underwater objects by means of a CCD camera is performed. The situation using active illumination by pulses of laser radiation is considered. Calculation is performed for the special case of the minimum size of an object detected at a prescribed depth of submersion in relation to its reflection factor. __________ Translated from Izmeritel’naya Tekhnika, No. 9. pp. 32–36, September, 2007.     

A Method of Attenuating High-Power Laser Radiation with 1.06 μm Wavelength Using a Diffraction Grating

Measurement Techniques - A method of attenuating high-power laser radiation using a small metal diffraction grating as an attenuator for power measurement was analyzed. The thermal operating modes...     

The calibration of a system for measuring the transmission of the atmosphere for laser radiation

A method of calibrating a system for measuring the transmission of laser radiation through the atmosphere along paths about 1 km long is proposed and tested on a model “experiment.” Translated from Izmeritel'naya Tekhnika, No. 9, pp. 52–54, September, 2008.     

Calculation of the radiation power absorbed by a photodiode from its experimental current-voltage characteristics

The effect of measurement errors in the current-voltage characteristics on the accuracy with which the radiation power q absorbed by the photodiode is determined is investigated theoretically. A procedure for measuring the current-voltage characteristic using exponential averaging is proposed, which enables experimental curves to be obtained that are uniform with respect to the measurement of the noise. Statistical distributions of the quantity q are presented from which the systematic and random errors due to the measurement noise are determined.     

Morphology, optical, and photoelectrochemical properties of electrodeposited nanocrystalline ZnO films sensitized with Cd x Zn1−x S nanoparticles

Nanocrystalline ITO/ZnO films formed by porous zinc oxide microplatelets 1–3 μm in size and 100–200 nm in thickness, which consist of 30–50 nm ZnO crystallites, were sensitized to visible light by Cd _x Zn_1?x S nanocrystals deposited using the method of successive ionic layer adsorption and reaction (SILAR). The composition of Cd _x Zn_1?x S nanocrystals as well as the dependence between molar Cd(II) fraction in the films and the ratio of cadmium and zinc nitrate concentrations in solutions used for the SILAR procedure were determined by a combination of electron, Raman, and energy-dispersive X-ray spectroscopies. The photovoltage observed at illumination of the ITO/ZnO/Cd _x Zn_1?x S heterostructures by white light (λ >400 nm) in aqueous Na₂S solution increases with a decrease of Cd(II) content proportionally to an increment in the conduction band potential of the Cd _x Zn_1?x S nanocrystals. The photocurrent density normalized to the light absorbance of the ITO/ZnO/Cd _x Zn_1?x S films increases by a factor of around four when the conduction band potential of Cd _x Zn_1?x S nanocrystals grows by 220 mV as a result of Cd(II) fraction changing from 1.0 to 0.62–0.67. The results show that Cd _x Zn_1?x S solid solutions are more advantageous sensitizers for the short-wavelength part of the sensitivity window of the liquid-junction solar cells (400–450 nm) than conventionally used cadmium sulfide.     

Statistical Analysis of the Tensile Strength of Oriented Polyamide-6 Fibers

Technical Physics Letters - Statistical analysis of distribution of the tensile strength of commercial oriented polyamide-6 (PA-6) fibers has been performed in the framework of the Gaussian and...     

Island size distribution under conditions of dislocation-surface diffusion in semiconductor heterostructures

A mechanism of Ostwald ripening of islands under conditions of dislocation-surface diffusion is suggested for semiconductor heterostructures with quantum dots. The island size distribution is calculated for the suggested growth mechanism. Experimental histograms are compared with calculated curves.