Publikační činnost Děkanátu fakulty / Publications of the Dean's office (600)

Permanent URI for this collectionhttp://hdl.handle.net/10084/139552

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Děkánátu fakulty FMT (600) v časopisech registrovaných ve Web of Science od roku 2020 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

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Now showing 1 - 20 out of 55 results

Physical properties of MnFeAl-based alloys affected by Mn content and annealing
(Elsevier, 2024) Životský, Ondřej; Szurman, Ivo; Gembalová, Lucie; Alexa, Petr; Uhlář, Radim; Čegan, Tomáš; Malina, Ondřej; Čížek, Jakub; Veverka, Miroslav; Goraus, Jerzy
The present study is devoted to the Mn 2.4 Fe 0.8 Al 0.8 and Mn 2 FeAl alloys prepared by induction melting and studied in their original and subsequently annealed states. The annealing was carried out at 773 K/100 h and 1073 K/100 h in the argon atmosphere. The microstructure, phase composition, magnetic properties, and atom arrangement are followed with regard to Mn content and annealing conditions. The scanning electron microscopy completed by the energy dispersive X-ray spectroscopy and neutron activation analysis has detected single-phase alloys with compositions close to the nominal ones. Their structure, analyzed by X-ray diffraction, was found to be primitive cubic beta -Mn with the lattice parameters of 0.6359(2) nm for Mn 2.4 Fe 0.8 Al 0.8 and 0.6339(1) nm for Mn 2 FeAl. The coherent potential approximation calculations and positron annihilation spectroscopy have allowed obtaining an overview to the arrangement of Mn, Fe, and Al atoms in the beta -Mn structure and formation of the open volume defects. It is shown that Mn atoms occupy predominantly 8c Wyckoff sites and remaining Mn, Fe and Al atoms occupy 12d sites in equal 1/3 proportion. The open volume defects, vacancies and vacancy clusters, occur in both alloys and both annealed states in a very low concentration. From the magnetic viewpoint, both alloys in the as -prepared state and after annealing at 773 K/ 100 h are paramagnetic at room temperature with transition to antiferromagnetic state at about 30 - 40 K. The ac susceptibility measurements have indicated spin glass nature of the Mn 2 FeAl alloys. The annealing at a higher temperature, 1073 K/100 h, has affected mainly Mn 2.4 Fe 0.8 Al 0.8 alloy manifesting a weak ferro-/ferrimagnetic contribution at room temperature contributing to a strong magnetic ordering below 42 K.
Silver-loaded poly(vinyl alcohol)/polycaprolactone polymer scaffold as a biocompatible antibacterial system
(Springer Nature, 2024) Vilamová, Zuzana; Šimonová, Zuzana; Bednář, Jiří; Mikeš, Petr; Cieslar, Miroslav; Svoboda, Ladislav; Dvorský, Richard; Rosenbergová, Kateřina; Kratošová, Gabriela
A chronic nonhealing wound poses a significant risk for infection and subsequent health complications, potentially endangering the patient‘s well‑being. Therefore, effective wound dressings must meet several crucial criteria, including: (1) eliminating bacterial pathogen growth within the wound, (2) forming a barrier against airborne microbes, (3) promoting cell proliferation, (4) facilitating tissue repair. In this study, we synthesized 8 ± 3 nm Ag NP with maleic acid and incorporated them into an electrospun polycaprolactone (PCL) matrix with 1.6 and 3.4 µm fiber sizes. The Ag NPs were anchored to the matrix via electrospraying water‑soluble poly(vinyl) alcohol (PVA), reducing the average sphere size from 750 to 610 nm in the presence of Ag NPs. Increasing the electrospraying time of Ag NP‑treated PVA spheres demonstrated a more pronounced antibacterial effect. The resultant silver‑based material exhibited 100% inhibition of gram‑negative Escherichia coli and gram‑positive Staphylococcus aureus growth within 6 h while showing non‑cytotoxic effects on the Vero cell line. We mainly discuss the preparation method aspects of the membrane, its antibacterial properties, and cytotoxicity, suggesting that combining these processes holds promise for various medical applications.
Dual-resonance split ring resonator metasurface for terahertz biosensing
(IEEE, 2024) Asim, Arslan; Čada, Michael; Ma, Yuan; Fine, Alan
In this article, the 'terahertz gap' has been addressed by designing a novel THz metasurface for potential use in biosensing applications. The metasurface sensor employs surface plasmon resonance (SPR). It operates in the 0-1 THz band. Two sharp reflection dips are provided by the sensor, which serve as indicators of analyte refractive index variations. Geometrical as well as compositional parameters of the biosensor design have been studied to optimize the performance in the targeted frequency band. The sensor design shows compatibility with different metals. The performance of the metasurface with gold, copper, and aluminum has been investigated. The metasurface geometry is decently resilient to fabrication tolerances. The sensor maintains its resonance conditions when the angle of incidence is changed with minor deviations in the spectral response, but the polarization state of the incident terahertz beam clearly disturbs the absorption peak. Therefore, the sensing performance is restricted to a maximum allowable incidence angle of 20. and circularly polarized terahertz beams. The resonance conditions for the metasurface appear around 0.4 and 0.7 THz. Both resonances have been investigated with respect to changes in the analyte refractive index. The chosen refractive index range is 1 to 1.5. The sensor response is calibrated by plotting the resonance frequency versus the refractive index. Least squares regression technique has been used to extract a data model for sensor response. Comparison of the proposed design with contemporary works has been incorporated into the article. The sensor provides sensitivities of 0.1614 and 0.23 THz/RIU. The electromagnetic simulations have been carried out through the finite element method (FEM).
Magneto-plasmonic “switch” device for magnetic field detection
(De Gruyter, 2024) Bsawmaii, Laure; Giraud, Pascal; El Haber, Gerges; Halagačka, Lukáš; Chatelon, Jean-Pierre; Jamon, Damien; Jourlin, Yves; Royer, François
This paper introduces a novel class of low-loss and cost-effective optical planar structures tailored for magnetic detection applications. These structures represent unconventional magneto-plasmonic devices specifically optimized for an 'optical switch' configuration. The structure consists of a 1D deep sinusoidal gold grating covered by a thin cobalt layer. In this unique arrangement, the excited plasmon induces a high-contrast switching phenomenon between the reflected free space intensity of specular (0th) and -1st diffracted orders, sensitive to any transverse magnetic fields applied to the cobalt layer. The use of these two distinct diffracted orders induces differential measurements, effectively mitigating common drift and perturbations. This innovative approach results in an enhanced detection sensitivity, showcasing the potential of these structures for advanced magnetic field sensing applications.
Enhancing photocatalytic g-C3N4/PVDF membranes through new insights into the preparation methods
(Elsevier, 2024) Vilamová, Zuzana; Sampaio, Maria J.; Svoboda, Ladislav; Bednář, Jiří; Šimonová, Zuzana; Dvorský, Richard; Silva, Cláudia G.; Faria, Joaquim L.
Fibrous membranes are crucial on the filtration of pollutants from air and water, but continued use can lead to a failure in effectiveness due to pollutant accumulation. To enhance durability, incorporating photocatalytic submicroparticles into these membranes appear as a solution. Here, we prepared a set of polyvinyl difluoride (PVDF) fibrous membranes modified with graphitic carbon nitride (g-C3N4) using three different methodologies. Their photocatalytic efficiency was investigated using phenol as model pollutant compound under visible light irradiation. Using g-C3N4 fibrous membranes modified by electrospinning blend a pseudo first-order kinetic constant (kapp) of 2.51 x 10-4 min-1 was observed for phenol degradation after 240 min reaction. Despite minimal particle adhesion the thermal treatment increased kapp to 5.41 x 10-4 min-1. The membranes prepared via chemical activation of PVDF exhibited the highest photocatalytic activity (kapp of 21.7 x 10-4 min-1). This superior activity was attributed to covalent bonds between PVDF and g-C3N4, allowing the formation of oxidative species.
Overlap and rotate - a simple method for predicting out-of-plane and in-plane orientations of heteroepitaxial thin films
(Elsevier, 2024) Tokarský, Jonáš; Molek, Jonáš
The production of heteroepitaxial thin films is increasingly important due to their considerable utility in technical practice. This usability is determined by their specific physical and chemical properties influenced by the mutual crystallographic substrate-film orientation, both the out-of-plane and the in-plane. The possibility of predicting these orientations would reduce the time and financial burden of their experimental determination. This study shows how the out-of-plane and the in-plane orientation of heteroepitaxial film can be predicted by simply calculating number of overlapping atoms in a system of two overlapping crystallographic planes, one of which rotates relatively to the other. Coordinates of atoms in the crystallographic planes are taken from bulk structures, which contributes to the simplicity of the method. The average number of overlapping atoms (calculated from a 360° rotation) and the maximum number of overlapping atoms (including a corresponding angle) indicate the out-of-plane and the in-plane orientation, respectively. The method is tested on various substrate/film systems (SrTiO3/ZnO, Al2MgO4/ZnO, MgO/ZnO, MgO/CuO, Si/Al, MoS2/Au) and the results are compared with experimental data obtained from the literature. The good agreement with the experimental data shows this method to be reliable and sufficiently accurate for heteroepitaxial thin films.
{001}⟨101⟩ texture evolution by preferential dynamic grain growth in Ti–37 mol%Nb alloy under plane strain compression at high temperatures
(Japan Institute of Metals and Materials, 2024) Umezawa, Osamu; Hayakawa, Yujiro; Schindler, Ivo; Fukutomi, Hiroshi
{001}< 101 > texture evolution in Ti-37 mol%Nb (Nb-46.5 mass%Ti) alloy was determined under plane strain compression at the temperatures of 800 degrees C, 950 degrees C, and 1100 degrees C, in which preferential dynamic grain growth (PDGG) took place. At lower temperature and higher strain rate such as 800 degrees C-10(-2)/s, almost no grain growth occurred in the transverse direction (TD), and the alpha-fiber + near {111}< 110 > in the gamma-fiber texture was developed, which was a stable orientation as deformation texture. At higher temperature and lower strain rate such as 1100 degrees C-10(-3)/s, the grain growth along the TD remarkably appeared by grain boundary bulging, and an extremely high pole density of the texture near the alpha-fiber, especially the rotated cube {001}< 101 >, evolved. A planar dislocation structure with pile-ups appeared and individual dislocations were uniformly distributed in the grains. The rotated cube texture fulfills the conditions of the deformation stability and the low Taylor factor in accordance with the PDGG mechanism. The essential aspect of the mechanism is the preferential growth of grains with a stable orientation for deformation and a low Taylor factor in the given deformation mode.
Spintronic terahertz emitters with integrated metallic terahertz cavities
(De Gruyter, 2024) Mičica, Martin; Wright, Adrien; Koleják, Pierre; Lezier, Geoffrey; Postava, Kamil; Hawecker, Jacques; De Vetter, Anna; Tignon, Jerome; Mangeney, Juliette; Jaffres, Henri; Lebrun, Romain; Tiercelin, Nicolas; Vanwolleghem, Mathias; Dhillon, Sukhdeep
Spintronic terahertz emitters (STEs), based on optical excitation of nanometer thick ferromagnetic/heavy metal (FM/HM) heterojunctions, have become important sources for the generation of terahertz (THz) pulses. However, the efficiency of the optical-to-THz conversion remains limited. Although optical techniques have been developed to enhance the optical absorption, no investigations have studied the application of THz cavities. Here, to enhance the THz efficiency of STEs in a selected THz spectral range, FM/HM structures are realized on ultra-thin sapphire layers with metallic mirrors to create lambda/4 THz resonant cavities. THz emission time domain spectroscopy of these STE/sapphire/mirror heterostructures, with sapphire thicknesses ranging from 110 mu m to 25 mu m, shows enhancement of the emitted THz field that fits the lambda/4 cavity resonance with up to a doubling of the field in the spectrum, and in agreement with temporal simulations of the emitted THz pulse. By taking advantage of birefringent materials, we further show the potential of control of the polarization state of the emitted THz pulse. This work shows the potential of enhancing and engineering THz emission from STEs using THz cavities that can be controlled over a broad spectral range, which can be easily combined with optical cavities.
Photocatalytic reduction of CO2 over Ti3+ self-doped TiO2-based nanomaterials
(Elsevier, 2024) Ricka, Rudolf; Wanag, Agnieszka; Kusiak-Nejman, Ewelina; Moszyński, Dariusz; Filip Edelmannová, Miroslava; Reli, Martin; Baďura, Zdeněk; Zoppellaro, Giorgio; Zbořil, Radek; Morawski, Antoni W.; Kočí, Kamila
In this study, we explored the photocatalytic efficacy of Ti3+-doped TiO2-based photocatalysts for CO2 reduction. The Ti3+ self-doped photocatalysts were synthesized using a straightforward chemical reduction with sodium borohydride (NaBH4). Our investigation aimed to elucidate the intricate interplay between the synthesis process and the quantity of NaBH4 reductant on the physical-chemical and photocatalytic attributes of the defective TiO2-based photocatalysts. We explored three different commercially available TiO2 materials labeled P25, (S) TiO2, and KRONOClean7050, which were reduced (2 g of TiO2) with 0.75 and 1.5 g of NaBH4. The reduction with 0.75 g of NaBH4 led to a significant decrease of photocatalytic activity in all three cases. It was caused by clogging of the photocatalysts surface by sodium ions which resulted in the surface recombination of charge carriers. Oppositely, the reduction with 1.5 g of NaBH4, led to an increase of the photocatalytic activity with superior performance of KRONOClean7050. The comprehensive characterization of all the samples explained this superior performance of KC7050_RED_1.5 sample. Importantly, it did not contain any amorphous phase and the crystal size was two times higher compared to other 2 samples reduced by 1.5 g of NaBH4. In the addition to higher crystallinity, the formation of a disordered TiO2_x layer, enriched with Ti3+ defects and oxygen vacancies, was confirmed. These structural features enhance the light absorption and mitigate undesired recombination of photogenerated charge carriers. These results would trigger farther investigation of defect engineering towards enhancement of the efficiency of metal oxide photocatalysts.
Tailoring the microstructure, mechanical properties, and electrical conductivity of Cu–0.7Mg alloy via Ca addition, heat treatment, and severe plastic deformation
(Springer Nature, 2024) Kalhor, Alireza; Rodak, Kinga; Tkocz, Marek; Myalska‑Głowacka, Hanna; Schindler, Ivo; Poloczek, Łukasz; Radwański, Krzysztof; Mirzadeh, Hamed; Grzenik, Michał; Kubiczek, Krzysztof; Kampik, Marian
The effects of 0.1 wt.% Ca addition, heat treatment, and SPD processing using the MaxStrain module of the Gleeble thermomechanical simulator on the microstructure, mechanical properties, and electrical conductivity of Cu-0.7Mg (wt.%) alloy were investigated in this work. The binary alloy exhibited a single-phase microstructure, whereas the ternary alloy featured uniform dispersion of Cu5Ca intermetallic particles inside the grains as well as on grain boundaries. These particles resulted in an average hardness that was 33% higher than that of the binary alloy, as well as 13% higher yield strength and 13% higher ultimate tensile strength. The heat treatment process not only enhanced the yield strength and ultimate tensile strength of the samples, but also resulted in the partial spheroidization of Cu5Ca particles within the microstructure of the ternary alloy, resulting in its improved ductility. Following MaxStrain processing, ternary samples exhibited a smaller grain size and a higher fraction of high-angle grain boundaries than binary samples, which was attributed to the vital role of Cu5Ca intermetallic particles in hindering the dislocation motion during deformation. MaxStrain-processed samples exhibited marginally lower electrical conductivities than their initial counterparts; yet, all MaxStrain-processed samples satisfied the electrical conductivity threshold for classification as HSHC Cu alloys.
Diffractive order Mueller matrix ellipsometry for the design and manufacture of polarization beam splitting metasurfaces
(Optica Publishing Group, 2024) Bjelland, Victoria M.; Hale, Nathan; Schwarz, Niklas; Vala, Daniel; Høvik, Jens; Kildemo, Morten
Optical metasurface technology promises an important potential for replacing bulky traditional optical components, in addition to enabling new compact and lightweight metasurface based devices. Since even subtle imperfections in metasurface design or manufacture strongly affect their performance, there is an urgent need to develop proper and accurate protocols for their characterization, allowing for efficient control of the fabrication. We present non-destructive spectroscopic Mueller matrix ellipsometry in an uncommon off-specular configuration as a powerful tool for the characterization of orthogonal polarization beam-splitters based on a-Si:H nanopillars. Through Mueller matrix analysis, the spectroscopic polarimetric performance of the ±1 diffraction orders is experimentally demonstrated. This reveals a wavelength shift in the maximum efficiency caused by fabrication-induced conical pillars while still maintaining a polarimetric response close to ideal non-depolarizing Mueller matrices. We highlight the advantage of the spectroscopic Mueller matrix approach, which not only allows for monitoring and control of the fabrication process itself, but also verifies the initial design and produces feedback into the computational design.
Immunotoxicity of stainless-steel nanoparticles obtained after 3D printing
(Elsevier, 2024) Olšovská, Eva; Lehotská Mikušová, Miroslava; Tulinská, Jana; Rollerová, Eva; Vilamová, Zuzana; Líšková, Aurélia; Horváthová, Mira; Szabová, Michaela; Svoboda, Ladislav; Gabor, Roman; Hajnyš, Jiří; Dvorský, Richard; Kukutschová, Jana; Lukán, Norbert
This study aims to investigate the in vitro effects of nanoparticles (NPs) produced during the selective laser melting (SLM) of 316 L stainless steel metal powder on the immune response in a human blood model. Experimental data did not reveal effect on viability of 316 L NPs for the tested doses. Functional immune assays showed a significant immunosuppressive effect of NPs. There was moderate stimulation (117%) of monocyte phagocytic activity without significant changes in phagocytic activity and respiratory burst of granulocytes. A significant dose-dependent increase in the levels of the pro-inflammatory cytokine TNF-a was found in blood cultures treated with NPs. On the contrary, IL-8 chemokine levels were significantly suppressed. The levels of the pro-inflammatory cytokine IL-6 were reduced by only a single concentration of NPs. These new findings can minimise potential health risks and indicate the need for more research in this area.
Effect of PWHT of X6Cr-NiNbN 25-20 steel on the evolution of the sigma phase during creep exposure at 700 °C
(Univerzita Jana Evangelisty Purkyně v Ústí nad Labem, 2023) Řehořek, Jakub
Superheaters and reheaters made of heat-resistant austenitic steels are being replaced in existing fossil fuel power plants to operate at Advanced Ultra Super Critical (A-USC) parameters of steam. Newly developed and used high nickel content austenitic steels, such as in X6Cr NiNbN 25-20, are predicted to significantly suppress the precipitation of a hazardous s-phase during long-term creep exposure. The sphase causes premature failure of the component during creep, which is usually supported by a local change in hardness in the case of welded assemblies. Experimental results show that PWHT significantly improved reduction of area. However, for the PWHT specimen with a shorter exposure time of 15,712 hours, there was an acceleration in the precipitation of sigma-phase particles during creep at 700 degrees C compared to the specimen in the AW state, after 20,557 hours.
Simulation of hot continuous rolling of a plain carbon steel using the MAXStrain II® multi-axis deformation system
(Polska Akademia Nauk, Instytut Metalurgii i Inżynierii Materiałowej, 2023) Schindler, Ivo; Kawulok, Petr; Konečná, Kateřina; Sauer, Michal; Navrátil, Horymír; Opěla, Petr; Kawulok, Rostislav; Rusz, Stanislav
A simple methodology was used for calculating the equivalent strain values during forming the sample alternately in two mutually perpendicular directions. This method reflects an unexpected material flow out of the nominal deformation zone when forming on the MAXStrain II device. Thus it was possible to perform two temperature variants of the simulation of continuous rolling and cooling of a long product made of steel containing 0.17% C and 0.80% Mn. Increasing the finishing temperature from 900°C to 950°C and decreasing the cooling rate from 10°C/s to 5°C/s led to a decrease in the content of acicular ferrite and bainite and an increase in the mean grain size of proeutectoid ferrite from about 8 µm to 14 µm. The result was a change in the hardness of the material by 15%.
On the optimal Cs/Co ratio responsible for the N2O decomposition activity of the foam supported cobalt oxide catalysts
(Elsevier, 2023) Klegová, Anna; Pacultová, Kateřina; Kiška, Tomáš; Gryboś, Joanna; Sojka, Zbigniew; Obalová, Lucie
Structured foam catalysts for N2O decomposition containing Co and Cs were prepared via conventional and organic-assisted impregnation method (acetic acid, citric acid, glycerol, glycine, urea). Organic-assisted impregnation caused higher abundance of smaller particles and different faceting. Glycerol usage leads to increase of specific rate constant for N2O decomposition, urea leads to its decrease. The optimal amount of Cs in Co3O4 deposited on the foam was 2–3 times higher than in the bulk Co3O4-Cs due to the dispersion of part of the Cs species over the bare support. The use of glycerol caused a better surface coverage by spinel phase, thus leaving less space for spreading the cesium on the support instead of on the spinel phase. The positive effect of glycerol on the performance of the catalysts with optimized cesium content was attributed to refaceting of the spinal nanocrystals, and greater resistance of the (1 0 0) planes to gaseous NO/H2O contaminates.
Unveiling the potential of composite water-swollen spiral wound membrane for design of low-cost raw biogas purification
(Elsevier, 2023) Wojnarová, Petra; Rusín, Jiří; Basinas, Panagiotis; Koštejn, Martin; Němec, Josef; Stanovský, Petr; Kim, Albert S.; Izák, Pavel
The present study aims to verify a novel purification method for raw biogas using water-swollen composite membranes. In two module configurations, we generated water-swollen polymer gel layers on thin-film composite membranes to separate methane from other biogas species. The primary driving force of the biogas separation is the solubility differences between major biogas species. The carbon dioxide solubility, many times higher than methane, effectively rejected methane from the water-swollen membranes and resulted in the retentate concentration of 97 vol% methane for raw biogas and 98 vol% for synthetic gas. Two membrane modules connected in parallel increased the methane recovery ratio up to 58 %. At a pressure of 3 bar the water-swollen membrane proved efficient in desulfurizing feed biogas producing an outlet stream containing a low concentration of H2S of an order of 10 ppmv.
Assessment of tensile properties across pressure vessel nozzle to primary piping safe-end employing instrumented indentation testing
(Elsevier, 2023) Négyesi, Martin; Žáková, Veronika; Mareš, Vratislav; Strnadel, Bohumír; Lacroix, Valéry; Choi, Min-Jae; Kwon, Dongil
This study deals with the assessment of tensile properties across the nozzle to primary piping safe-end employing the instrumented indentation testing (IIT). Standard tensile tests were performed in order to validate the results of IIT. Tensile properties were also estimated from conventional hardness test. Both the yield strength and tensile strength measured by IIT were in satisfactory agreement with the results of standard tensile tests and were found superior compared to the values estimated from the conventional hardness measurement. Highest deviation between the results of IIT and tensile tests was found in the regions of weldments. IIT showed as capable of measuring the variation of tensile properties across the pressure vessel nozzle to primary piping safe-end. Moreover, IIT has the advantage over the tensile testing that specimens do not need to be extracted from the studied piece and more detailed distribution of mechanical properties can be acquired.
Characterization of Zn-Mg-Sr type soldering alloy and study of ultrasonic soldering of SiC ceramics and Cu-SiC composite
(MDPI, 2023) Koleňák, Roman; Pluhár, Alexej; Drápala, Jaromír; Babincová, Paulína; Pašák, Matej
The aim of the research was to characterize the soldering alloy type Zn-Mg-Sr and direct the soldering of SiC ceramics with Cu-SiC-based composite. It was investigated whether the proposed composition of the soldering alloy was appropriate for soldering those materials at the defined conditions. For the determination of the solder melting point, TG/DTA analysis was applied. The Zn-Mg system is of the eutectic type with a reaction temperature of 364 ◦C. The effect of strontium on the phase transformation was minimal, owing to its lower content. The microstructure of the soldering alloy type Zn3Mg1.5Sr is formed of a very fine eutectic matrix containing segregated phases of strontium—SrZn13 and magnesium—MgZn2 and Mg2Zn11. The average tensile strength of the solder is 98.6 MPa. The tensile strength was partially increased by solder alloying with magnesium and strontium. The SiC/solder joint was formed due to the distribution of magnesium from the solder to the boundary with the ceramics at the formation of a phase. Owing to soldering in air, oxidation of the magnesium took place and the oxides formed were combined with the silicon oxides that remained on the surface of the ceramic material—SiC. Thus, a strong bond based on oxygen was obtained. An interaction between the liquid zinc solder and the copper matrix of the composite substrate took place at the formation of a new phase—γCu (Cu5Zn8 ). The shear strength was measured on several ceramic materials. The average shear strength of the combined SiC/Cu-SiC joint fabricated with Zn3Mg1.5Sr solder was 62 MPa. When soldering similar ceramic materials mutually, a shear strength of as much as around 100 MPa was observed.
Removal of pharmaceutical micropollutants from real wastewater matrices by means of photochemical advanced oxidation processes – A review
(Elsevier, 2023) Kulišťáková, Alena
The vast majority of current technologies used for wastewater treatment are unable to remove pharmaceutical micropollutants. These are discharged to surface water bodies and cause serious problems for fragile natural ecosystems. The expansion of the current legislation for surface water, including the addition of new priority substances, including nine pharmaceuticals, has already been published by the European Commission. After entering into force, every EU member state will have to ensure the monitoring and limitation of the discharging of listed pharmaceuticals. Since current treatment methods are insufficient, new technology needs to be developed. Photochemical advanced oxidation processes (AOPs) are among the most tested methods for wastewater treatment and show high micropollutant removal efficiency. Thus, photochemical AOPs seem to be a promising way to reduce the pharmaceutical burden in wastewater. However, there are still challenges limiting the wide and simple use in wastewater treatment plants. This review was written to fulfill the necessity of summarizing and assessing of current trends in the usage of photochemical AOPs in the treatment of real wastewater matrices, focusing on pharmaceutical micropollutants. To the best of the author's knowledge, the topic was processed for the first time.
Spin vertical-cavity surface-emitting lasers with linear gain anisotropy: Prediction of exceptional points and nontrivial dynamical regimes
(American Physical Society, 2023) Drong, Mariusz; Peřina Jr., Jan; Fördös, Tibor; Jaffres, Henri Y.; Postava, Kamil; Drouhin, Henri-Jean
It is shown that when the linear gain anisotropy is properly accounted for, spin-injected vertical-cavity surface-emitting lasers (spin-VCSELs) offer interesting functionalities. Using the extended spin-flip model (SFM), we predict the existence of exceptional points (EPs) in spin-VCSELs and two interesting phenomena which accompany EPs, namely, (i) the polarization switching manifesting as induced change of field helicity sign and (ii) frequency comb generation without the need of external injection locking. Both effects have tremendous technological potential such as fast on-chip polarization switching, and most importantly, their concepts are not limited only to spin-VCSEL technology. We discuss the concept of anisotropy-engineered non-Hermitian microlasers and we provide a theoretical background to study their polarization dynamics near EPs.

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