Study of Local Ice Loads Measured at Norströmsgund Lighthouse

It is believed that ice loading can be a stationary process at least sometimes during the state of continuous brittle crushing. Confidence in the distribution law, stationarity in time, and autocorrelation function of local ice loads is the key factor for assessment of such loads and their successful simulation. Good understanding of the load process on the level of a single transducer record can be helpful in future analysis and simulation of loads on wider contact areas. In this paper local loads, simultaneously measured by two middle subpanels at the Norströmsgrund lighthouse in March 2001, are studied. Stationary time series of lognormal origin of 50 seconds duration are extracted from both of the subpanel records. From the studied data, stationarity was not observed simultaneously at different subpanels. The correlation of one stationary subpanel record with simultaneous record of the other subpanel found to be weak. A simple function with good fit to the observed autocorrelation curve of stationary load fragments is suggested. The findings are compared with parameters obtained for local loads in previous studies. A transition from autocorrelation function for raw lognormal data to autocorrelation function of logarithmic normal data is performed.

Nonradiative and Radiative Recombination in CdS Polycrystalline Structures

Properties of polycrystalline CdS layers, employed in formation of the CdS-Cu2S heterostructures, have been studied by combining contactless techniques of the time and spectrally resolved photoluminescence (TR-PL) spectroscopy and microwave-probed photoconductivity (MW-PC) transients. The confocal microscopy has been employed to correlate the homogeneity of photoluminescence and grain size in CdS layers. Three types of samples with crystallite grain size of <1 μm (the I-type) and of 2–10 μm of homogeneous (II-type) and inhomogeneous (III-type) grain distribution have been separated. The simultaneous record of MW-PC and TR-PL responses ensures the same sampling area on the layer under investigation, as both (MW-PC and TR-PL) signals are generated by the same UV laser excitation beam. Two PL bands peaked at 500 and 700 nm were revealed. It has been demonstrated that photoluminescence intensity strongly depends on the properties of the polycrystalline 15–26 μm thick CdS layers with equilibrium carrier density of about1.5×1013 cm−3, which serve as the substrates to form CdS-Cu2S junctions. The different carrier decay components were ascribed to different microareas with characteristic MW-PC and PL decay lifetimes of 2–10 ns, ascribed to microcrystallites with PL instantaneous decay lifetimes of 40–200 ns, and MW-PC decay lifetimes in the range of 100–1000 μs attributed to the inter-crystallite areas of CdS polycrystalline material.