Superconducting electronics is a rapidly growing field in micro- and nanoelectronics. Various planar structures, such as Josephson junctions, exhibit intriguing phenomena with potential applications in spin-based and quantum devices. However, the integration density of these thin-film digital components is still lower than that of semiconductor elements. The nanometer-scale miniaturization of Josephson junctions can be achieved by using a new approach, such as nanowire-based geometry. This article reports an automated electrochemical method for producing segmented Au/Ni/Au nanowires with diameters less than 100 nm. The potentiostatic electrodeposition of metals from different baths using coulometric control leads to the formation of segments with narrow length distributions and well-defined boundaries. The ability to fabricate coarse-grained gold segments and single-crystal ferromagnetic nickel layers as thin as 7 nm has been demonstrated. For a nanowire-based Nb/Au/Ni/Au/Nb hybrid structure with planar Nb electrodes and a 7-nm-thick Ni segment, a critical current of 0.6 mu A at 1.2 K has been detected. The low-temperature transport properties are described by an effective resistance model, in which the Ni ferromagnetic layer exhibits ballistic electron transport. The fabricated structures represent the first example of miniature SFS Josephson junctions based on individual segmented nanowires that demonstrate proximity-induced superconducting behavior. These findings pave the way for designing compact, F-containing digital devices for superconducting nanoelectronics and spintronics.

Based on comprehensive studies of fragments of antique red-glazed pottery (terra sigillata) of the Pontic, Bosporan, and Eastern groups, characteristic technological features of the slip layer and ceramic bulk have been identified. The Eastern-sigillata samples exhibited the best quality. The small size of the pores and inclusions suggests the use of finely dispersed clay. In addition, a mixture of two types of clay (ferrous and more refractory calcareous) was revealed. The special and, apparently, careful preparation of the clay suspension for the slip layer production included addition of a potassium-containing preparation, presumably, potassium potash (to glaze better the layer), as well as an iron-containing pigment, likely, ochre. The firing temperature for this group of samples was about 1000°C. Pontic sigillata products differed from the Eastern pottery by a lower content of potassium potash and the absence of specially added pigment in the varnish layer. The firing temperature was lower: 850–900°C. The Bosporan products are characterized by much less thorough preparation of both the clay raw material as a base and the varnish layer, as well as the lowest firing temperature in comparison with other groups (500–900°C).

In this paper, we discuss the prediction of the delivery efficiency of magnetic carriers based on their properties and field parameters. We developed a theory describing the behavior of magnetic capsules in the capillaries of living systems. A partial differential equation for the spatial distribution of magnetic capsules has been obtained. We propose to characterize the interaction between the magnetic field and the capsules using a single vector, which we call “specific magnetic force”. To test our theory, we performed experiments on a model of a capillary bed and on a living organism with two types of magnetic capsules that differ in size and amount of magnetic material. The experimental results show that the distribution of the capsules in the field correlated with the theory, but there were fewer actually accumulated capsules than predicted by the theory. In the weaker fields, the difference was more significant than in stronger ones. We proposed an explanation for this phenomenon based on the assumption that a certain level of magnetic force is needed to keep the capsules close to the capillary wall. We also suggested a formula for the relationship between the probability of capsule precipitation and the magnetic force. We found the effective value of a specific magnetic force at which all the capsules attracted by the magnet reach the capillary wall. This value can be considered as the minimum level for the field at which it is, in principle, possible to achieve a significant magnetic control effect. We demonstrated that for each type of capsule, there is a specific radius of magnet for which the effective magnetic force is achieved at the largest possible distance from the magnet’s surface. For the capsules examined in this study, the maximum distance where the effective field can be achieved does not exceed 1.5 cm. The results of the study contribute to our understanding of the behavior of magnetic particles in the capillaries of living organisms when exposed to a magnetic field.

A novel approach for the preparation of ferroelectric composite films has been successfully developed by combining sol-gel evaporation-induced self-assembly (EISA) of porous lead zirconate titanate (PZT) films with atomic layer deposition (ALD) of titania. The EISA process, which utilizes a Brij-type surfactant, facilitates the formation of large columnar perovskite grains with narrow (similar to 20 nm) interconnected pores. ALD, employing the thermal reaction of titanium isopropoxide with water, ensures uniform titania growth within the pores throughout the film thickness, as demonstrated by transmission electron microscopy and ellipsometric porosimetry. The resulting PZT-TiOx composite films exhibit a pronounced photovoltaic current under visible light illumination, attributed to electron excitation from the valence band to Ti3+ states, followed by movement via a hopping conduction mechanism. The photocurrent value varies with the direction of polarization. This behavior presents a potential method for controlling photoconductivity through polarization, with possible applications in electronic and photonic devices.

AIM:This study establishes the mechanism of stable emulsion capsules formation using sulfhydryl-free polysaccharides (xanthan gum, chitosan, and their mixtures), comparing ultrasonic versus conventional mechanical preparation methods. METHODS:Capsules were fabricated using both mechanical and ultrasonic processing, followed by comprehensive characterization through DLS, CLSM, CRYO electron microscopies, XPS, FTIR, AFM, XRD, and TGA. RESULTS:Ultrasonically processed xanthan gum/chitosan capsules exhibit a well-defined morphology (1 μm average size), stable surface characteristics (-19 mV zeta potential), and enhanced resistance to aggregation and coalescence. The results demonstrate not only formation of polyelectrolyte complexes in the mixed shells (with xanthan gum/chitosan ratios of 1 and 1.17 for mechanically and ultrasonically prepared capsules, respectively, with an initial 1:1 polymer solution ratio), but also reveals molecular scissoring effects. Structural characterization reveals semi-crystalline shell organization with significantly improved mechanical strength, as evidenced by the 48 kPa Young's modulus. The capsules exhibit excellent hemocompatibility (hemolysis rate < 0.02 μL/mL) for intravenous delivery applications. CONCLUSION:Our findings reveal fundamental insights into polysaccharide behavior on the phase interface under ultrasonication, demonstrating how acoustic energy drives molecular reorganization to create structurally superior capsules. This work provides a new paradigm for polysaccharide-based drug carrier design to create high-performance delivery systems with enhanced stability.

The paper reports an analysis of surface morphology variation and cavity pattern formation in silicon single crystal induced by ion implantation and post-implantation annealing in different regimes. Critical implantation doses required to promote surface erosion are determined for samples subjected to post-implantation annealing and in absence of post-implantation treatment. For instance, implantation with helium ions to fluences below 3 × 1017 He+/cm2 without post-implantation annealing does not affect the surface morphology; while annealing of samples implanted with fluences of 2 × 1017 He+/cm2 and higher promotes flaking.

In this study we demonstrate formation of all-carbon heterostructures induced by field electron emission from diamond needle-shaped crystallites with nanoscale tips. We show that at certain experimental conditions a carbon nanoprotrusion can be formed at the apex of a diamond emitter. Staircase-like current-voltage curves observed for such emitters indicated the presence of the Coulomb blockade effect in the self-assembled all-carbon heterostructures. The mechanism of nanoprotrusion formation via the field-induced surface diffusion of carbon atoms is revealed by observing the structural transformation of the emitter material using transmission electron microscopy. We also explore how the properties of the formed heterostructures evolve with the field emission current, and show that the characteristic size of the formed nanoprotrusion depends on the dimensions of the diamond nanotip. The developed approach offers a way to reproducible fabrication of heterostructured emitters which can be applied as coherent single-electron sources in vacuum nanoelectronics and electron quantum optics.

The influence of the structure of copper powder particles on the catalytic activity of the CeO2/Cu catalyst was studied using the methods of X-ray diffraction, electron microscopy, electron diffraction, energy dispersive X-ray analysis, as well as temperature-programmed reduction of CO (CO-TPR). Nanocomposites were obtained by mechanochemical synthesis using copper particles differing in size and morphology: micron-sized dendrites and nanoparticles. It was shown that the activity of the catalyst obtained from nanosized copper is two times higher, which is due to the presence of CuxO clusters located on the atomic steps of cerium oxide nanocrystals. This arrangement of clusters apparently prevents blocking of activating centers. Thus, the surface structure of cerium oxide particles formed when using nanosized copper powder is a key factor responsible for the catalytic activity.

The single-pass one-step method for printing conductive silver tracks on a glass surface, using the laser-induced forward transfer (LIFT) technique, was proposed, providing a unique opportunity for high-throughput printing of surface micro- and nanostructures with high electrical conductivity and positioning accuracy. This method was developed via our multi-parametric research, resulting in the selection of the optimal material, laser irradiation, and transfer conditions. Optical, scanning and transmission electron, and atomic force microscopy methods, as well as X-ray diffraction, were used to characterize the surface structure and phase state of the printed structures, while energy-dispersive X-ray and X-ray photoelectron microscopy were employed for their chemical microanalysis. Depending on the laser irradiation parameters, the specific electrical conductivity of the printed tracks varied from 0.18 to 83 kS/cm, approaching that of donor magnetron-sputtered films. This single-pass one-step method significantly facilitates fast, large-scale, on-demand local laser printing of metallic (sub)microcomponents of microelectronic devices.

The subject of this study is the conducting tracks on the surface of monocrystalline silicon. The aim of this study is to develop an effective one-stage method for forming the conductive elements of electrical circuits on silicon. Method. A conductive silver layer is deposited using laser-induced direct transfer from a donor substrate. The selection of laser radiation parameters enables us to determine the optimal transfer mode to achieve the maximum conductive layer conductivity. The surface topography and chemical composition are studied using scanning and transmission electron microscopy and energy-dispersive X-ray and photoelectron spectroscopy. Main results. The maximum specific conductivity (approximately 54 kS/cm) is obtained when transferring a silver film using laser radiation with a wavelength of 1064 nm, a pulse duration of 120 ns, and a power density of 0.21 GW/cm2. / cm 2 . The scanning speed in this case is 2000 mm/s, which ensures the arrival of approximately two laser pulses at each point of the film, resulting in the transfer of the film material particles to the silicon substrate and their subsequent sintering. Practical significance. The method presented in the paper can be used to form the conductive elements of electrical circuits with high specific conductivities in one stage while simplifying the technological process of their formation and reducing its duration. (c) 2024 Optica Publishing Group

An effect of Cu powder dispersion and morphology on the surface structure and the physical–chemical and catalytic properties of Cu–CeO2 catalysts prepared by mechanochemical synthesis was studied in the preferential CO oxidation in a H2-rich stream (CO-PROX). Two catalysts, produced by 30 min ball-milling from CeO2 and 8 mass% of copper powders and with particle sizes of several tens (dendrite-like Cu) and 50–200 nm (spherical Cu obtained with levitation-jet method), respectively, were characterized by X-ray diffraction and electron microscopy methods, a temperature-programmed reduction with CO and H2, and with Fourier-transform infrared spectroscopy. The catalyst synthesized from the “large-scale” dendrite-like Cu powder, whose surface consisted of CuxO (Cu+) agglomerates located directly on the surface of facetted CeO2 crystals with a CeO2(111) and CeO2(100) crystal planes exposition, was approximately two times less active at 120–160 °C than the catalyst synthesized from the fine Cu powder, whose surface consisted of CuxO (Cu2+) clusters of 4–6 nm in size located on the steps of facetted CeO2 nanocrystals. Although a large part of CO2 reacted with a ceria surface to give carbonate-like species, no blockage of CO-activating centers was observed due to the surface architecture. The surface structure formed by the use of highly dispersed Cu powder is found to be a key factor responsible for the catalytic activity.

The nanogratings of controllable topography are in a great demand in optics, photonics, and sensing, although their fast, flexible, and large scale fabrication could be a challenge for lithography and other modern methods. In this article we offer a simple method of creation the patterned coatings based on the direct laser-driven creation of periodical surface structures on thin titanium films. By controlling the laser polarization, 1D and 2D square and honeycomb patterns of a fully manageable topography were created on Ti film deposited onto glass substrate under cross-scanning irradiation by nanosecond near-IR laser pulses. Comprehensive study was conducted on the formation mechanisms, internal structure, and optical properties of 1D and 2D gratings. The article also discusses the optical properties of the gratings, demonstrating that various optical effects can be obtained by controlling the orientation angles of the gratings. A polarizing filter prototype was generated by dynamically controlling the laser polarization. The resulting patterns have high repeatability and controllable optical properties, making them suitable for various applications including photonics, polarization optics, and security labeling.

In this work, materials based on lanthanum zirconates with a pyrochlore structure were prepared by a deposition with ultrasonic spraying. This method combines good variability and scalability. Various approaches to modernize the microstructure of samples and to reduce sintering temperature were applied. For instance, the use of small amounts of sintering additive 0.5 wt.

High-temperature polymer-electrolyte membrane fuel cells (HT-PEMFCs) are a very important type of fuel cells since they operate at 150–200 °C, making it possible to use hydrogen contaminated with CO. However, the need to improve the stability and other properties of gas-diffusion electrodes still impedes their distribution. Self-supporting anodes based on carbon nanofibers (CNF) are prepared using the electrospinning method from a polyacrylonitrile solution containing zirconium salt, followed by pyrolysis. After the deposition of Pt nanoparticles on the CNF surface, the composite anodes are obtained. A new self-phosphorylating polybenzimidazole of the 6F family is applied to the Pt/CNF surface to improve the triple-phase boundary, gas transport, and proton conductivity of the anode. This polymer coating ensures a continuous interface between the anode and proton-conducting membrane. The polymer is investigated using CO2 adsorption, TGA, DTA, FTIR, GPC, and gas permeability measurements. The anodes are studied using SEM, HAADF STEM, and CV. The operation of the membrane–electrode assembly in the H2/air HT-PEMFC shows that the application of the new PBI of the 6F family with good gas permeability as a coating for the CNF anodes results in an enhancement of HT-PEMFC performance, reaching 500 mW/cm2 at 1.3 A/cm2 (at 180 °C), compared with the previously studied PBI-O-PhT-P polymer.

In this work, a doping strategy was used to achieve a good conductivity in samarium zirconate which crystallizes in the pyrochlore. The production of nanopowders made it possible to form high-density ceramics with an optimal microstructure. It is shown that intrinsic and impurity defects coexist in Sm2-xCaxZr2O7-delta, impairing ion transport at high doping levels. Despite this, Sm(1.95)Ca(0.05)Zr(2)O(7-delta )maintains low activation energy of the parent and has good ionic conductivity (10(-3) S center dot cm(-1) at 600 degree celsius) which is one of the largest among oxide pyrochlores. It has been shown to have a good chemical stability. The material has a thermal expansion coefficient (TEC) of 12 ppm K-1 which is higher than YSZ and provides better compatibility with electrode materials. The above makes it possible to successfully use it as a highly stable oxygen electrolyte or an intermediate thin layer at the electrolyte-electrode interface in electrochemical devices.

The process of stone formation in the human body remains incompletely understood, which requires clinical and laboratory studies and the formulation of a new endogenous, nanotechnological concept of the mechanism of origin and formation of crystallization centers. Previously, the mechanism of sialolithiasis was considered a congenital disease associated with the pathology of the ducts in the structure of the glands themselves. To date, such morphological changes of congenital nature can be considered from the position of the intrauterine formation of endogenous bacterial infections complicated by the migration of antigenic structures initiating the formation of crystallization centers. The present work is devoted to the study of the morphology and composition of stones obtained as a result of surgical interventions for sialolithiasis. Presumably, nanoparticles of metals and other chemical compounds can be structural components of crystallization centers or incorporated into the conditions of chronic endogenous inflammation and the composition of antigenic structures, in complexes with protein and bacterial components. X-ray microtomography, X-ray fluorescence analysis, scanning transmission electron microscopy and microanalysis, mass spectrometry, and Raman spectroscopy were used to study the pathogenesis of stone formation. Immunoglobulins (Igs) of classes A and G, as well as nanoparticles of metals Pb, Fe, Cr, and Mo, were found in the internal structure of the stones. The complex of antigenic structures was an ovoid calcified layered matrix of polyvid microbial biofilms, with the inclusion of metal nanoparticles and chemical elements, as well as immunoglobulins. The obtained results of clinical and laboratory studies allow us to broaden the view on the pathogenesis of stone formation and suggest that the occurrence of the calcification of antigenic structures may be associated with the formation of IgG4-associated disease.

Polyacrylonitrile and polyheteroarylenes, such as polybenzimidazole (PBI) and a polymer of intrinsic microporosity (PIM-1), have been employed to prepare nanoporous electrospun carbon nanofiber (CNF)-based materials for high-temperature proton-exchange (or polymer-electrolyte) membrane (HT-PEM) fuel cells. The nanoporous CNF mats are obtained by Nanospider (needle-free) electrospinning method from polymer solution followed by pyrolysis at 1500 degrees C to form nanoporous electrospun polymer nanofiber self-supporting mats with micropores (D < 2 nm) and mesopores (D 2-50 nm). The nanoporous CNF samples are extensively characterized by N-2 and CO2 adsorption applying the BET, BJH, Dubinin-Radushkevich (DR), NLDFT, and GCMC methods, CO2 uptake, Raman spectroscopy, elemental analysis, electrical conductivity, electron microscopy, and XPS. The role of the polymer precursor on the obtained values of specific surface area (SSA) and volume for micro- and mesopores is presented and discussed. The PBI-based CNF material reaches a micropore SSA of 919 m(2) g(-1) and CO2 uptake of 4.0 mmol g(-1) derived from CO2 adsorption (273 K) data, and a micropore SSA of 873 m(2) g(-1) according to the t-method derived from N-2 adsorption data. Close values confirm higher accessibility of micropores compared with the case of PIM-based CNF, where the micropore SSA values derived from CO2 and N-2 adsorption data are different and indicate the partial inaccessibility of micropores for low-temperature nitrogen adsorption (77 K). Platinum-decorated CNF mats are successfully tested as electrodes for HT-PEM fuel cells, showing the feasibility of using the mats as cathodes; nevertheless, further optimization is required. For CNF anodes, the HT-PEM fuel cell performance reaches 0.69 V at 0.2 A cm(-2) and 0.53 W cm(-2) at 1.4 A cm(-2) which permits the use of the Pt/CNF mats as anodes.

Fuel cells on polybenzimidazole (PBI) membrane belong to high-temperature polymer-electrolyte membrane fuel cells (HT-PEMFC). When a polymer-electrolyte complex of PBI with o-phosphoric acid (PA) is applied as a proton-conducting membrane, the proton conductivity is provided without humidification above 120°C. Hydrogen-air HT-PEMFCs are able of operating effectively at 150–200°C, which allows application of technical hydrogen contaminated with CO as fuel. However, it should be noted that application of conventional “thin-film” Pt/C electrodes based on electrically conductive carbon black with Pt nanoparticles in aggressive PA environment results in electrochemical corrosion of carbon, which leads to the loss of Pt electrocatalyst particles and their aggregation (Ostwald ripening). Evidently, there is a need to replace the carbon black with more stable carbon nanostructured materials. It has been shown that self-supporting mats (essentially “felt”) based on carbon nanofibers (CNF) can be used as HT-PEMFC anodes. The CNF mats were obtained in three stages. At the first stage, the nanofiber precursor material was obtained by electrospinning of solution of a copolymer of acrylonitrile with methyl acrylate (with addition of ZrCl4). Then, the mats were stabilized by thermal oxidation (350°C, air). Afterwards, the CNFs were kept in Zn(NO3)2 (porogen) solution and pyrolyzed (1000 ^∘ C, vacuum). To improve the proton conductivity, N-phosphonoethylated cardo poly(benzimidazole) (PBI-PhT-P) was deposited on the CNF surface which leads to an improvement in the performance characteristics of HT-PEMFC. The obtained materials were examined by electron microscopy. Their specific surface area and specific volume were investigated by the N2 and CO2 adsorption methods (up to 597 m2/g and 0.170 cm3/g). After Pt deposition, the CNFs were successfully tested as anodes (up to 0.4 mA/cm2 at 625 mV) in hydrogen-air HT-PEMFC.

The emission of nanoscale particles from the surfaces of dental implants leads to the cumulative effect of particle complexes in the bone bed and surrounding soft tissues. Aspects of particle migration with the possibility of their involvement in the development of pathological processes of systemic nature remain unexplored. The aim of this work was to study protein production during the interaction of immunocompetent cells with nanoscale metal particles obtained from the surfaces of dental implants in the supernatants. The ability to migrate nanoscale metal particles with possible involvement in the formation of pathological structures, in particular in the formation of gallstones, was also investigated. The following methods were used: microbiological studies, X-ray microtomography, X-ray fluorescence analysis, flow cytometry, electron microscopy, dynamic light scattering, and multiplex immunofluorescence analysis. For the first time, titanium nanoparticles in gallstones were identified by X-ray fluorescence analysis and electron microscopy with elemental mapping. The multiplex analysis method revealed that the physiological response of the immune system cells, in particular neutrophils, to nanosized metal particles significantly reduced TNF-a production both through direct interaction and through double lipopolysaccharide-induced signaling. For the first time, a significant decrease in TNF-a production was demonstrated when supernatants containing nanoscale metal particles were co-cultured with proinflammatory peritoneal exudate obtained from the peritoneum of the C57Bl/6J inbred mice line for one day.