Ferrocenyl-substituted fluorescent anthracenes and anthraquinones

The synthesis of a range of ferrocene-substituted ethynylanthracenes and 1,1^′-(bis-(2-ethenylanthraquinoyl)ferrocene has been achieved. The synthesis relies on the production of ferrocenylanthraquinones as key precursors. The products were obtained in the reactions of ferrocenylanthraquinones with phenylethynyllithium or trimethylsilylethynyllithium followed by reduction with tin chloride. The key products such as 1- and 2-ferrocenyl(9,10-bis-phenylethynyl)anthracenes have been characterised by X-ray single crystal diffraction.     

Parametric Frequency Converters Based on New Nonlinear Crystals

Results of investigations into the physical properties of a number of new nonlinear crystals are presented. The parameters of frequency converters manufactured on their basis are compared, and second-harmonic generation of CO₂ lasers first excited by frequency conversion in LiInSe₂, AgGa_{1– x} In_xSe₂, Ag_xGa_xGe_xS_{2(1 + x)}, and Hg_1–x Cd_xGa₂S₄ crystals is investigated. The superiority of HgGa₂S₄, Hg_1–x Cd_xGa₂S₄, and AgGa_1–x In_xSe₂ over the well-known crystals has been demonstrated for frequency conversion both within the middle-IR range and from the visible range to the middle-IR range. Advantages of LiInSe₂ and AgGa_1–x In_xSe₂ crystals are demonstrated for the direct frequency conversion of femtosecond laser radiation to the middle-IR range compared to the cascade frequency conversion and direct frequency conversion in LiInS₂ crystals.     

Justification of Averaging Method for Multifrequency Impulsive Systems

We prove new theorems on the justification of the averaging method for multifrequency oscillation systems with pulse influence at fixed times.     

The Transformation Matrix of Vibrational Waves

The general theory on the transformation of elastic waves at a rigid nodal junction of an arbitrary number of thin plates is considered. The notion of transformation marix is introduced, and a way for computing it and numerical examples are given. Properties of the transformation matrix resulted from the reciprocity principle and the energy conservatin law are studied. In particular, a new relation that expresses the energy conservation low for the case where a wave damped in the direction of the joint of plates is a source of a field is obtained. Bibliography: 18 titles.     

Changes in the Laser-Induced Fluorescence Spectrum of Myocardium Tissue with Decrease in Its Viability

We investigated the laser-induced fluorescence spectra (LIF) of porcine cardiac tissues with different degrees of viability. The data obtained are compared with the results of routine histological investigations and also with the experiments performed with the use of fluorescent probes. It has been found with a high degree of reliability that the loss of the viability of the myocardium tissue leads to the alteration of its LIF spectra. This can be used for low-invasive rapid control of transplant viability in the process of its preparation and during surgery.     

Double adaptive notch filter for mechanical grain flow sensors

Nowadays, commercial combine harvesters are equipped with special sensors for the purposes of precision farming. Sensors are installed to measure the harvested surface and mass flow each second. Hence, grain yield maps are constructed, approximating the actual grain yield on the field before harvesting.Most grain flow sensors are installed on the paddle elevator before storage in the grain tank. At the elevator exit, paddles throw packs of grain against a curved plate on which a force transducer is attached. Therefore, the measured flow signal is heavily disturbed by the paddle rate and resonance frequency of the mechanical sensor.In this study, a computationally cheap method is presented to track both frequencies in the measured flow signal. Based on these frequency trackers, a double notch filter is tuned continuously to remove both disturbances. Moreover, the knowledge about the frequency content can be used to monitor the condition of the mechanical sensor and the paddle elevator.     

Relaxor properties of Fe-doped TlInS<Subscript>2</Subscript>

The relaxor properties of Fe-doped TlInS₂ crystals are investigated. It is shown that Fe-doped TlInS₂ compounds exhibit all features inherent in relaxor ferroelectric materials. The temperature range of existence of the microdomain (relaxor) state and the temperature of the transition from this state to a macro-domain state are determined.     

An EOQ model with process reliability considerations

The classical economic order quantity (EOQ) model assumes that items produced are of perfect quality and that the unit cost of production is independent of demand. However, in realistic situations, product quality is never perfect, but is directly affected by the reliability of the production process. In this paper, we consider an EOQ model with imperfect production process and the unit production cost is directly related to process reliability and inversely related to the demand rate. In addition, a numerical example is given to illustrate the developed model. Sensitivity analysis is also performed and discussed.