Influence of the measurement configuration on the results of Raman microspectroscopy of human hair

Increasing interest in spectroscopic studies of human hair raises the question about the accuracy of measurement of their spectra and requires optimisation of experimental facilities. An original method of obtaining transverse hair sections without using a microtome and chemical influence is proposed. The results obtained by confocal Raman microspectroscopy of human hair differently oriented with respect to the optical axis of the measuring setup are compared. It is shown that, in addition to expected changes in the spectra measured at different distances from the hair periphery in the direction to its centre, the spectra measured in the case of hair excitation perpendicular and parallel to its axis are also considerably different.

A Compact High Gain Printed Antenna with Frequency Selective Surface for 5G Wideband Applications

In this article, a frequency selective surface (FSS) based compact wideband printed antenna radiator with improved gain and directivity is proposed for sub-6 GHz 5G wireless networking applications. Due to their inherent property of possessing spatial filtering characteristics, FSSs are attracting the interest of researchers. An approach for increasing the gain and the directivity by integrating a band pass FSS on a compact built patch antenna radiator is proposed here. The architecture equations for designing the band pass FSS using double square loop geometry are defined. The printed patch antenna radiator (PAR) and a double square loop frequency selective surface (DSLFSS) are designed and integrated. The simulation results are verified using the results from the measuring setup. The output response is giving a fractional bandwith of 19.14% with 5.5 dBi gain and 6.2 dBi of directivity and thus makes it the good choice for 5G applications.

Polyoxazolines with a Vicinally Double-Bioactivated Terminus for Biomacromolecular Affinity Assessment

Interactions between proteins and carbohydrates with larger biomacromolecules, e.g., lectins, are usually examined using self-assembled monolayers on target gold surfaces as a simplified model measuring setup. However, most of those measuring setups are either limited to a single substrate or do not allow for control over ligand distance and spacing. Here, we develop a synthetic strategy, consisting of a cascade of a thioesterification, native chemical ligation (NCL) and thiol-ene reaction, in order to create three-component polymer conjugates with a defined double bioactivation at the chain end. The target architecture is the vicinal attachment of two biomolecule residues to the α telechelic end point of a polymer and a thioether group at the ω chain end for fixating the conjugate to a gold sensor chip surface. As proof-of-principle studies for affinity measurements, we demonstrate the interaction between covalently bound mannose and ConA in surface acoustic wave (SAW) and surface plasmon resonance (SPR) experiments.

Investigations of Electrical and Optical Parameters of Some LED Luminaires—A Study Case

In the paper, the electrical and optical parameters of wirelessly controlled LED lamps of the Hue type are analysed. Features of this class of wirelessly controlled LED lamps given by the producer are described and a measuring setup for the electrical and optical parameters of the considered LED lamps is proposed. The results of measurements of the two investigated lamps with variable hue, based on RGB chips or emitted white light of different CCTs (correlated colour temperatures), are shown and discussed. Attention was given to the parameters characterising the influence of the tested LED lamp on such electric power quality indicators as PF (power factor) and THD (total harmonic distortion). Therefore, the influence of voltage supply and the selected value of power density of the emitted light on the THD and PF is analysed and discussed.

Measurement of the dielectric properties of paratellurite at microwaves using a biconical resonator

The results of measurements of the dielectric parameters of TeO2 samples in the microwave range are presented. The measurements were carried out in X-band by the cavity perturbation method using a measuring setup based on a biconical resonator. The advantages of using a high-Q biconical resonator for measuring the dielectric parameters of a paratellurite sample are considered. The determination of the dielectric parameters of the samples is based on finite element computational model and using digital method for determining the natural frequency by fractional rational approximation of the frequency response. The influence of the deviation of the sample shape from the cylindrical on the resonator parameters and the measurement error is considered. The estimate of the dielectric constant of TeO2 in the crystallographic direction [110] was 24.4, the dielectric loss factor such as tanδ is estimated as 3·10-4. The results obtained are in good agreement with the reference results presented in the scientific literature.

Method for measuring the speed parameters of photodetectors

The article discusses the difficulties that arise when measuring the speed parameters of modern broadband photodetector devices by a method based on the measurement results of the rise time of the transition characteristic are considered. As a solution of the described problems a method is proposed for quantitatively evaluating of speed parameters using the results of determining the impulse response of the studied photodetector. The source of the test signals is a pulsed fiber laser operating in the self-mode locking mode and generating ultrashort (about 3 ps) optical pulses. The article describes in detail the method itself, the measuring setup that allows it to be implemented, and presents some results of experimental testing of the method