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Politechniki Gdańskiej

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  • Efficient Gradient-Based Algorithm with Numerical Derivatives for Expedited Optimization of Multi-Parameter Miniaturized Impedance Matching Transformers
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2019 Pełny tekst RADIOENGINEERING

    Full-wave electromagnetic (EM) simulation tools have become ubiquitous in the design of microwave components. In some cases, e.g., miniaturized microstrip components, EM analysis is mandatory due to considera¬ble cross-coupling effects that cannot be accounted for otherwise (e.g., by means of equivalent circuits). These effects are particularly pronounced in the structures in¬volving slow-wave compact cells and their numerical opti¬mization is challenging due to expensive simulations and large number of parameters. In this paper, a novel gradi¬ent-based procedure with numerical derivatives is pro¬posed for expedited optimization of compact microstrip impedance matching transformers. The method restricts the use of finite differentiation which is replaced for se¬lected parameters by a rank-one Broyden updating for¬mula. The usage of the formula is governed by an ac¬ceptance parameter which is made dependent on the pa¬rameter space dimensionality. This facilitates handling circuits of various complexities. The proposed approach is validated using three impedance matching transformer circuits with the number of parameters varying from ten to twenty. A significant speedup of up to 50 percent is demon¬strated with respect to the reference algorithm.

  • Efficient synthesis and antifungal investigation of nucleosides’ quaternary ammonium salt derivatives
    • Barbara Dmochowska
    • Lucyna Pellowska-Januszek
    • Justyna Samaszko
    • Rafał Ślusarz
    • Roland Wakieć
    • Janusz Madaj
    2019 Pełny tekst TURKISH JOURNAL OF CHEMISTRY

    Quaternary ammonium salts are a group of compounds with diverse biological properties, the most important of which are their antiviral, antibacterial, and antifungal activities. The quaternization reactions of 5'-O-tosyl derivatives of uridine and thymidine with triethylamine, trimethylamine, 4-(N ,N -dimethylamino)pyridine, 2-methylpyridine, and pyridine are described in this article. Two of the synthesized compounds are exceptional because they are first of this type that demonstrate concentration-dependent antifungal in vitro activity against two species of the genus Candida in minimal YNB-SG medium. The experimental results have been extended by adding full atom molecular dynamics simulations and substrates and products energies evaluation.

  • Ekonometryczna analiza konsumpcji w Polsce w latach 1995-2018- statyczne modele wydatków konsumpcyjnych w wartościach nominalnych
    • Jerzy Ossowski
    2019 Pełny tekst Przestrzeń Ekonomia Społeczeństwo

    W artykule przeprowadzono badania makroekonomicznych związków pomiędzy konsumpcją globalną (C) a produktem krajowym brutto (PKB). W części teoretycznej artykułu: • zdefiniowano postacie analityczne przyczynowo-skutkowych makromodeli konsumpcji, • sformułowano interpretację mierników opisujących badane zależności, • sformułowano założenia stochastyczne dla rozważanych makromodeli konsumpcji, W części empirycznej artykułu: • przeprowadzono analizę i interpretację danych statystycznych oraz podstawowych mierników charakteryzujących makroekonomiczne procesy konsumpcji w Polsce w latach 1995-2018, • oszacowano parametry strukturalne proponowanych wersji modeli, • przeprowadzono weryfikację oszacowanych wersji modeli, • zinterpretowano oszacowane i zweryfikowane mierniki. Ostatecznie w stosunku do konsumpcji ogółem (CON) oraz konsumpcji gospodarstw domowych (CN) wykazano, że w gospodarce polskiej w latach 1995-2018: • z każdego dodatkowego miliarda nominalnego produktu krajowego brutto (PKBN) społeczeństwo przeznaczało na konsumpcję ogółem (CON) około 0,744 miliarda złotych z przeciętnym błędem wynoszącym 0,034 miliarda złotych. • z każdego dodatkowego miliarda nominalnego produktu krajowego brutto (PKBN) gospodarstwa domowe przeznaczały na swoją indywidualną konsumpcję (CN) około 0,574 miliarda złotych z przeciętnym błędem wynoszącym 0,029 miliarda złotych.

  • Ekspertyza dotycząca wpływu tlenków żelaza na nowy rurociąg ze stali nierdzewnej gat. 1.4307 podwieszany pod mostem stalowym nad rzeką Wisłą, który jest połączony z dwóch stron z magistralą wodociągową wykonaną z rur z żeliwa szarego.
    • Łukasz Gaweł
    2019

    Przedmiotem niniejszej umowy jest dokonanie oceny wpływu na nowy rurociąg ze stali nierdzewnej (1.4307), związków żelaza rozpuszczonych w wodzie oraz związków żelaza odłożonych w starych przewodach z żeliwa szarego, a które to związki przemieszczają się pod wpływem zmian kierunku przepływu wody oraz uderzeń hydraulicznych. Ponadto przedmiot stanowi ocena wpływu produktów korozji na stan stali nierdzewnej i układu żeliwo/stal nierdzewna.

  • Elastic Fender-Dolphin Interaction for Economic Design of Berthing Dolphins
    • Waldemar Magda
    2019 JOURNAL OF WATERWAY PORT COASTAL AND OCEAN ENGINEERING-ASCE

    The study addresses the question of the possible design benefits when considering the interaction between a modern marine modular rubber fender and a steel tubular pile substructure of a berthing dolphin. Absorption of the berthing kinetic energy of the vessel by a dualelasticity pile-fender berthing system is described in detail using the interactive treatment method (ITM). Application of the ITM is illustrated by a calculative example, assuming a 37,700 deadweight ton (DWT) tanker as a berthing ship, realistic geometries of large-diameter steel piles of the berthing dolphin substructure, and a family of Sumitomo Pi-type modular rubber fender units. By splitting the berthing kinetic energy into two parts absorbed by two elastic component elements of the dual-elasticity system of the berthing dolphin, the ITM is an effective tool for proper selection of the minimum required size (i.e., outside diameter and wall thickness) of steel piles of the berthing dolphin substructure in relation to the size of fender unit assumed. Finally, using ITM, an example analysis is performed to illustrate the influence of fender size selection on the berthing force, and the mass and stiffness of the steel-pile substructure of the berthing dolphin, as meaningful parameters influencing the most economical solution in the berthing dolphin design.

  • Elastic scattering of electrons from chloroform
    • Borna Hlousek
    • M. F. Martin
    • Murtadha Khakoo
    • Mateusz Zawadzki
    • G. M. Moreira
    • L. S. Maioli
    • Marcio Bettega
    • L Machado
    • V. A. S. da Mata
    • A. J. da Silva
    • I Iga
    • M-T Lee
    • M Homem
    2019 Pełny tekst PHYSICAL REVIEW A

    We present experimental and theoretical cross sections for elastic electron scattering from CHCl3. This is an important target because of its relevance to environmental chemistry and the plasma etching industry as a source of chlorine radicals. The experimental results were obtained at incident electron energies ranging from 0.5 to 800 eV in the 10deg-130deg scattering angle range. Theoretically, the scattering cross sections in the low-energy region were obtained by using the Schwinger multichannel method with pseudopotentials in the static-exchange plus polarization approximation. Additionally, in the low- and intermediate-energy ranges, theoretical calculations were also performed using a molecular complex optical potential and a single-center expansion method combined with Padé approximation. Further calculations using the independent atom model were also made at intermediate energies. Momentum-transfer cross sections were derived by integrating the differential cross sections. In general, there is a good agreement between the experimental data and the theoretical results. Moreover, the calculations reveal the presence of three shape resonances in the elastic channel, located at 0.5, 2, and 8 eV. The two higher-lying resonances were confirmed by the present experiments, whereas the positions of the two lower-lying resonances agree well with previous results of electron attachment experiments.

  • Electrical properties of organic and perovskite systems used in solar cells
    • Damian Głowienka
    2019 Pełny tekst

    Nowadays, a great progress in the areas of molecular and hybrid photovoltaics is observed. The devices based on organic and perovskite materials are getting attention mostly due to their low cost production process. However, their efficiency and stability are still lower than for inorganic materials which make them less popular. Therefore, a detailed understanding of the device physics is fundamental for organic and perovskite solar cells. The goal of this thesis is to understand which processes influence the electrical properties of both types of solar cells. Here, numerical and experimental techniques are used to accurately determine and understand electrical phenomena taking place in both photovoltaic cells. The special attention is paid to different effects, including excitonic processes, interface phenomena or recombination mechanisms which affect the photovoltaic parameters. The results of the thesis should help in further development of aforementioned solar cells.

  • Electrochemical behavior of a composite material containing 3D-structured diatom biosilica
    • Andrzej Nowak
    • Myroslav Sprynskyy
    • Weronika Brzozowska
    • Anna Lisowska-Oleksiak
    2019 Pełny tekst Algal Research-Biomass Biofuels and Bioproducts

    3D-structured diatom biosilica mixed with conducting carbon black was investigated as an active electrode material for lithium-ion batteries. Diatom biosilica was obtained by cultivation of the selected diatom species under laboratory conditions. Several instrumental techniques (XRD, FTIR, Raman, SEM-EDX, TGA) were used to characterize the physicochemical properties of applied biosilica. It was evidenced that the prepared new composite material has a significant impact on the electrochemical properties of the electrode. The ratio 1:1 of biosilica and carbon black exhibited a specific capacity of 400 ± 9 mAh/g over 90 cycles. Such a ratio ensured proper electric contact between biosilica particles. The specificity of the faradaic process suggests that biosilica-based electrodes might be suitable in large-scale energy storage applications.

  • Electrochemical capacitor temperature fluctuations during charging/discharging processes
    • Stanisław Galla
    • Arkadiusz Szewczyk
    • Łukasz Lentka
    2019 Pełny tekst Metrology and Measurement Systems

    Thepaperpresentsaproposalofusingadditionalstatisticalparameterssuchas:standarddeviation,variance, maximum and minimum increases of the observed value that were determined during measurements of temperature fields created on the surface of the tested electrochemical capacitor. The measurements were carriedoutusingthermographicmethodsinordertosupportassessmentoftheconditionofelectrochemical capacitorunderclassicdurabilitytestsbasedonmethodsofdeterminationofcapacityandequivalentseries resistance.Thepossibilityofusingsomestatisticalparametersinassessmentoftheelectrochemicalcapacitor quality was illustrated. The applied measurement methodology and the results of research associated with the classic methods of supercapacitors’ assessment are presented. The obtained results indicate that the variabilityofsomestatisticalparametersoftemperaturefieldscanbedirectlyrelatedtochangingthevalues of standard parameters describing electrochemical capacitor, which are capacitance and equivalent series resistance.

  • Electrochemical degradation of textile dyes in a flow reactor: effect of operating conditions and dyes chemical structure
    • A Pieczyńska
    • Tadeusz Ossowski
    • Robert Bogdanowicz
    • E.m. Siedlecka
    2019 Pełny tekst International Journal of Environmental Science and Technology

    In this study, electrochemical oxidation of five azo dyestuffs (Yellow D-5GN, Red D-B8, Ruby F-2B, Blue D-5RN, Black DN), that are widely used in the textile industry, was investigated in a flow reactor. BDD electrode with a high boron doping level (C/B = 10 000) was prepared and used. Two configurations of reactor were considered, i.e., one with the undivided cell, and the other with the cell divided by anodic and cathodic compartments. The effect of current density and the initial pH of the solution on the dyestuff degradation process was investigated. As expected, higher degradation rate was found for higher current density, while the effect of pH was marginal. Next, electrochemical oxidation of azo dyestuffs with different chemical structures was investigated. Based on the cyclic voltammetry measurements, the correlation between the dyestuff removal rate and the oxidation potential value of dyestuff was found. These results suggest that the direct oxidation of dyestuffs at the highly doped BDD anode plays a significant role in the electrochemical oxidation. Finally, the electrochemical removal of dyestuffs was carried out in two types of dyeing baths. The dyeing bath composition has a significant effect on the degradation efficiency. Chlorides in F-type dyeing bath accelerated electrochemical removal due to effective generation of Cl2/HOCl at the highly B-doped BDD anode. In contrast, OH− inhibited the D-type dyestuff removal from dyeing bath, because they acted as scavengers of ·OH radicals. Highly B-doped BDD anode is promising material to F-type dyestuff treatment in industrial wastewater.

  • Electrochemical performance of indium-tin-oxide-coated lossy-mode resonance optical fiber sensor
    • Paweł Niedziałkowski
    • Wioleta Białobrzeska
    • Dariusz Burnat
    • Petr Sezemsky
    • Vitezslav Stranak
    • Harm Wulff
    • Tadeusz Ossowski
    • Robert Bogdanowicz
    • Marcin Koba
    • Mateusz Śmietana
    2019 SENSORS AND ACTUATORS B-CHEMICAL

    Analysis of liquids performed in multiple domain, e.g., optical and electrochemical (EC), has recently focus significant attention. Our previous works have shown that a simple device based on indium-tin-oxide (ITO) coated optical fiber core may be used for optical monitoring of EC processes. At satisfying optical properties and thickness of ITO a lossy-mode resonance (LMR) effect can be obtained and used for monitoring of optical properties of an analyte in proximity of the ITO surface. However, EC response of the ITO-LMR device to a redox probe has not been achieved for ITO-LMR sensor whereas it is generally observed for commercially available ITO electrodes. The changes in the response to a redox probe are typically used as a sensing parameter when EC label-free sensing is considered, so it is crucial for further development of combined LMR-EC sensing concept. In this work, we focus on enhancing the EC activity of the device by tuning ITO magnetron sputtering deposition parameters. Influence of the deposition pressure on the ITO properties has been the main consideration. Both optical and EC readouts in 0.1 M KCl containing such redox probes as 1 mM of K3[Fe(CN)6] or 1 mM 1,1′-Ferrocenedimethanol were discussed at different scan rate. The performed studies confirm that for optimized ITO properties the ITO-LMR sensor used as the EC electrode may also show excellent EC performance. The observed EC processes are quasi-reversible and diffusion-controlled. Moreover, for the devices, which offer improved EC response, an optical monitoring of the EC process is also possible. According to our best knowledge, fully functional combined optical and EC sensor, where optical effect is resonance-based and other than well-known surface plasmon resonance, is presented for the first time.

  • Electrochemical properties of porous Sr0.86Ti0.65Fe0.35O3 oxygen electrodes in solid oxide cells: Impedance study of symmetrical electrodes
    • Aleksander Mroziński
    • Sebastian Molin
    • Jakub Karczewski
    • Tadeusz Miruszewski
    • Piotr Jasiński
    2019 Pełny tekst INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    This work evaluates porous Sr0.86Ti0.65Fe0.35O3 (STF35) as a possible oxygen electrode material for Solid Oxide Cells. The powder synthesis was performed by solid state method. Characterization included DC electrical conductivity study of sintered bulk samples and impedance spectroscopy study of symmetrical electrodes deposited on gadolinium doped ceria substrates. Measurements were carried out in atmospheres with different pO2 levels: 0.1%–20% O2. Detailed equivalent circuit analysis was carried out in order to clarify the reaction pathway on porous electrode, which extends knowledge available for dense model electrodes. At 800 °C in 21% O2, the DC electrical conductivity of STF35 pellet was 0.6 S cm−1 and the polarization resistance of the electrode in the symmetrical cell was ∼100 mΩ cm2. Detailed impedance spectroscopy studies revealed that the largest contribution (∼80%) towards the polarization resistance is due to oxygen adsorption, which is limiting the oxygen reduction performance of the porous STF35 electrode. These results show the applicability of advanced impedance analysis methods (e.g. Distribution of Relaxation Times - DRT) for description of complex impedance electrode phenomena of porous electrodes.

  • Electrochemical simulation of metabolism for antitumor-active imidazoacridinone C-1311 and in silico prediction of drug metabolic reactions
    • Agnieszka Potęga
    • Dorota Żelaszczyk
    • Zofia Mazerska
    2019 Pełny tekst JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS

    The metabolism of antitumor-active 5-diethylaminoethylamino-8-hydroxyimidazoacridinone (C-1311) has been investigated widely over the last decade but some aspects of molecular mechanisms of its metabolic transformation are still not explained. In the current work, we have reported a direct and rapid analytical tool for better prediction of C-1311 metabolism which is based on electrochemistry (EC) coupled on-line with electrospray ionization mass spectrometry (ESI-MS). Simulation of the oxidative phase I metabolism of the compound was achieved in a simple electrochemical thin-layer cell consisting of three electrodes (ROXYTM, Antec Leyden, the Netherlands). We demonstrated that the formation of the products of N-dealkylation reactions can be easily simulated using purely instrumental approach. Newly reported products of oxidative transformations like hydroxylated or oxygenated derivatives become accessible. Structures of the electrochemically generated metabolites were elucidated on the basis of accurate mass ion data and tandem mass spectrometry experiments. In silico prediction of main sites of C-1311 metabolism was performed using MetaSite software. The compound was evaluated for cytochrome P450 1A2-, 3A4-, and 2D6-mediated reactions. The results obtained by EC were also compared and correlated with those of reported earlier for conventional in vitro enzymatic studies in the presence of liver microsomes and in the model peroxidase system. The in vitro experimental approach and the in silico metabolism findings showed a quite good agreement with the data from EC/ESI-MS analysis. Thus, we conclude here that the electrochemical technique provides the promising platform for the simple evaluation of drug metabolism and the reaction mechanism studies, giving first clues to the metabolic transformation of pharmaceuticals in the human body.

  • Electrochemical Stability of Few-Layered Phosphorene Flakes on Boron-Doped Diamond: A Wide Potential Range of Studies in Aqueous Solutions
    • Anna Dettlaff
    • Grzegorz Skowierzak
    • Łukasz Macewicz
    • Michał Sobaszek
    • Jakub Karczewski
    • Mirosław Sawczak
    • Jacek Ryl
    • Tadeusz Ossowski
    • Robert Bogdanowicz
    2019 Pełny tekst Journal of Physical Chemistry C

    Two-dimensional phosphorene has attracted great interest since its discovery as a result of its extraordinary properties. Two-dimensional single crystals of phosphorene can be useful for electrochemical (EC) sensing applications due to their enhanced surface-to-volume ratio. We proposed to investigate the electrochemical performance of phosphorene deposited directly on boron-doped diamond (BDD) electrodes. Noncovalent interaction of phosphorene with BDD was achieved due to van der Waals interactions. This extends the potential range of EC studies in aqueous solutions due to the extraordinary wide range of the BDD potential window (−2 to 2.5 V vs Ag|AgCl|3M KCl). Cyclic voltammetry studies demonstrated irreversible electrochemical oxidation of the phosphorene, with peaks observed at different potentials depending on the sonication power during the liquid exfoliation of black phosphorus (BP). This indicated the formation of polyphosphoric quasi-oxide layers with undefined oxidation states of phosphorus. Electrochemical impedance spectroscopy showed the second time constant for high power sonicated BP, which was attributed to PxOy(OH)z formation. The subsequent film was responsible for limiting the charge transfer rate. The BDD enabled the EC behavior of phosphorene to be studied at high anodic potentials.

  • Electrodes array for contactless ECG measurement of a bathing person - a sensitivity analysis
    • Kamil Osiński
    • Adam Bujnowski
    • Piotr Przystup
    • Jerzy Wtorek
    2019 Pełny tekst

    An applicability of a remote (contactless) electrocardiogram (ECG) measurements in a bathtub is presented in the paper. Possibility of ECG measurements in shallowly filled tube with a water was examined. A bathing person was, both, sitting and lying during experiments performed. The problem became non-trivial when the bathing person was moving in reference to a fixed set of electrodes and located at the longer walls of the bathtub. However, the results obtained indicate that the sensitivity of a developed electrode array could enable such measurements. However, a spatial sensitivity distribution determines, both, the recorded ECG signal parameters and quality.

  • Electromagnetic plane wave scattering from a cylindrical object with an arbitrary cross section using a hybrid technique
    • Piotr Kowalczyk
    • Rafał Lech
    • Małgorzata Warecka
    • Adam Kusiek
    2019 Pełny tekst JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS

    A hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open and closed areas is presented. The main idea of the analysis is based on the utilization of the finite-element method to calculate the post impedance matrix and combine it with external excitation. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of the scatterer. Moreover, once the impedance matrix is calculated, any rotation or shifting of the post can be performed without the need for structure recalculation. All the obtained results have been verified by comparison with simulations performed using the hybrid finite-difference-modematching method and commercial software.

  • Electromagnetic-based derivation of fractional-order circuit theory
    • Tomasz Stefański
    • Jacek Gulgowski
    2019 Pełny tekst Communications in Nonlinear Science and Numerical Simulation

    In this paper, foundations of the fractional-order circuit theory are revisited. Although many papers have been devoted to fractional-order modelling of electrical circuits, there are relatively few foundations for such an approach. Therefore, we derive fractional-order lumped-element equations for capacitors, inductors and resistors, as well as Kirchhoff’s voltage and current laws using quasi-static approximations of fractional-order Maxwell’s equations. The proposed approach is not limited by the geometry of the considered lumped elements and employs the concepts of voltage and current known from the circuit theory. Finally, the proposed theory of circuit elements is applied to interpretation of Poynting’s theorem in fractional-order electromagnetism.

  • Electron collisions with X(CH3)4 molecules (X = C, Si, Ge)
    • Sylwia Stefanowska-Tur
    • Paweł Możejko
    • Elżbieta Ptasińska-Denga
    • Czesław Szmytkowski
    2019 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    Absolute grand-total cross sections (TCSs) for electron scattering from tetramethylmethane [C(CH3)4], tetramethylsilane [Si(CH3)4], and tetramethylgermane [Ge(CH3)4] molecules have been measured at electron-impact energies extending from around 0.5 to 300 eV in the linear electron-transmission experiment. The measured TCS energy dependences show very pronounced broad enhancement, peaking near 5.5 eV for Si(CH3)4 and Ge(CH3)4 molecules and around 6.5 eV for C(CH3)4. Additional weak structures are also located at higher electron energies. We attributed the TCS features to the resonant processes involved in the electron–molecule scattering. To examine the role of permethylation in the scattering, the measured TCS energy functions for X(CH3)4 compounds (X = C, Si, Ge) have been compared to the TCS curves for XH4 molecules. Additionally, the integral elastic cross section (ECS) and ionization cross section (ICS) have been calculated from intermediate to high electron-impact energies using model methods. At energies above 50 eV, the sum of ECS and ICS for the investigated targets is in satisfactory agreement with the respective measured TCS. The computed ECS+ICS values can be used as rough estimation of TCS at energies above 300 eV.

  • Electron energy-loss spectroscopy of excited states of the diazine molecules: Pyridazine
    • Ireneusz Linert
    • Mariusz Zubek
    2019 JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA

    Excitation of the valence electronic states of the pyridazine molecules in the gas phase have been studied using the technique of electron energy-loss spectroscopy. Varying the electron scattering conditions, the residual electron energy and scattering angle, enabled the optically-allowed and -forbidden excitations to be differentiated. The measured energy-loss spectra enabled the vertical excitation energies of the observed states to be determined and tentative assignments for them to be obtained. Comparison of the available vertical excitation energies of the correlating triplet and singlet states of the diazine molecules, pyridazine, pyrimidine and pyrazine, allowed systematic trends in the energy shifts to be determined.

  • Electron scattering from tin tetrachloride (SnCl4) molecules
    • Paweł Możejko
    • Sylwia Stefanowska-Tur
    • Elżbieta Ptasińska-Denga
    • Czesław Szmytkowski
    2019 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    Absolute grand-total cross section (TCS) for electron scattering from a tin tetrachloride, SnCl4, molecule was measured at electron-impact energies ranging from 0.6 to 300 eV, in the linear electron-transmission experiment. The measured TCS energy dependence shows two very pronounced enhancements peaking near 1.2 eV and around 9.5 eV, separated with a deep minimum centered close to 3 eV. The low energy structure is attributed to the formation of two short-living negative ion states. Additional weak structures in the TCS curve are also perceptible. We also calculated the integral elastic and ionization cross sections for SnCl4 up to 4 keV within the additivity rule approximation and the binary-encounter-Bethe approach, respectively. To examine the role of the central atom of tetrachloride target molecules in collisions with electrons, we compared the experimental TCS energy functions for XCl4 molecules (X = C, Si, Ge, Sn).