Beilstein Journal of Nanotechnology最新文献

The preservation of cultural heritage sites and objects faces critical challenges due to natural aging, environmental degradation, and human-induced damage such as vandalism and graffiti. This review article explores recent advancements in protective strategies for heritage materials including stone, concrete, ceramic, glass, metal, wood, and textiles. Special attention is given to the development and application of superhydrophobic and superoleophobic coatings, which offer promising defense against moisture, pollutants, and oily substances. These functional surfaces, often based on coatings consisting of polymeric, ceramic, and composite materials, can provide durable, non-invasive protection tailored to specific substrate weaknesses and exposure environments (indoor and outdoor). Objective of this review article is to critically examine the most recent studies and materials innovations relevant to cultural heritage site preservation. First the assessment of substrate vulnerabilities and environmental threats is presented, followed by a detailed analysis of coating types and compositions. It concludes with emerging trends, challenges, and future perspectives, offering a valuable resource for researchers, conservators, and materials scientists committed to the long-term safeguarding of historical artifacts and monuments.

In taxa such as insects, spiders, bats, frogs, and lizards, adhesive structures at the distal ends of their limbs have independently evolved, enabling the animals to adhere to inclined or even inverted surfaces. The adhesive apparatus of geckos functions via a complex interaction among muscles, bones, vascular tissue, and microscopic epidermal microstructures. The microstructures of geckos are classifiable as spinules, spines, prongs and setae, but only setae, which possess spatulate tips, promote adhesive competency sufficient to support body mass employing van der Waals forces. Several studies indicate that the form of toepad microstructures might be specific to the exploitation of the attributes of the substrata employed during habitat use. The species-rich genus Cyrtodactylus exhibits extensive variation in the shape of the subdigital scales associated with different habitats, making it a promising candidate for studying toepad evolution. We investigated the subdigital microstructures of 27 Cyrtodactylus species occupying a wide range of habitats, and exhibiting a spectrum of subdigital morphology, from the presence of the ancestral condition of small, rounded scales to the early-stage development of macroscopically visible incipient toepads. Using SEM and phylogenetic comparative analyses, our objectives were to (a) clarify how integumentary microstructural traits relate to the presence of incipient toepads and (b) identify potential adaptations linked to specific habitat types. We hypothesized that (1) species showing incipient toepad development will possess setae, while those lacking obvious macrostructural modifications should exhibit only spines, prongs, or spinules. Additionally, we hypothesized that either (2) the presence of setae is associated with arboreal lifestyles and, to a lesser extent, with rock-dwelling ecotypes; or (3) alternatively, microstructural traits are more strongly influenced by phylogeny, with closely related species exhibiting more similar toepad features than those more distantly related. We found setae, spines, and prongs on the incipient toepads. Spines were found to be the ancestral subdigital microstructures of Cyrtodactylus, with multiple independent transitions to prongs (three times) and setae (twice). One shift towards setae defines a largely seta-bearing clade, exhibiting a strong phylogenetic signal and supports our third hypothesis. Most transitions to incipient toepads occurred within this clade, consistent with hypothesis 1, and we reveal that the evolution of setae likely preceded that of broadened scales. Although microstructure types did not significantly correlate with ecotype, specific morphometric traits varied significantly among both microstructure types and ecotypes.

This work introduces the results of characterizing free-standing reduced graphene oxide paper, given its potential use as an electrode material in lithium-ion cells. Mildly reduced graphene oxide paper underwent further thermal reduction steps. The structural and chemical properties of the obtained materials were determined using Raman and Fourier-transform infrared spectroscopies and elemental combustion analysis. The morphology and thickness were determined with scanning electron microscopy imaging. This paper also reveals electrical and electrochemical properties of the material. The conductivity of the material obtained at 800 °C reached ≈70 S/cm, and the discharge capacity reached ≈160 mAh/g at 100 mA/g current density.

The diode effect in superconducting materials has been actively investigated in recent years. Plenty of different devices have been proposed as a platform to observe the superconducting diode effect. In this work, we discuss the possibility of a highly efficient superconducting diode design with controllable polarity. We propose a mesoscopic device that consists of two separated superconducting islands with proximity-induced ferromagnetism deposited on top of a three-dimensional topological insulator. Using the quasiclassical formalism of the Usadel equations, we demonstrate that the sign of the diode efficiency can be controlled by magnetization tuning of a single superconducting island. Moreover, we show that the diode efficiency can be substantially increased in such a device. We argue that the dramatic increase of the diode efficiency is due to competing contributions of the two superconducting islands to the supercurrent with single helical bands linked through the topological insulator surface.

Understanding nanoparticle adhesion to substrates is the key for their stability and performance in many applications, including energy systems, nanofabrication, catalysis, and electronic devices. In this study, we present a methodology for examining adhesion of copper nanoparticles to silicon substrates deposited under varying conditions using DC magnetron sputter inert gas condensation. Atomic force microscopy was utilized as a tool for the manipulation of the nanoparticles and to measure lateral forces for their displacement, with cantilever calibration achieved through wedge and diamagnetic lateral force calibrator methods. The work of adhesion was quantified by integrating the obtained lateral forces over the distance moved during manipulation, revealing a non-monotonic dependency on nanoparticle size with maximum adhesion observed for particles between 6 and 12 nm. In addition, an applied positive substrate bias voltage led to more energetic landing conditions and thus to increased adhesion forces. This study underscores the suitability of atomic force microscopy in characterizing adhesion on the nanoscale and offers insights into future strategies for tailoring nanoparticle/substrate interactions.

In this paper we present the results of the development, fabrication, measurements, and analysis of terahertz-range oscillators based on Josephson junction arrays embedded into the central electrode of a coplanar line. The influence of array geometry, the presence of a matched load at the nonradiating edge, and the magnitude of the tunneling current density of Josephson junctions on such oscillator characteristics as radiation power, linewidth, and operating range are discussed. Various options are suggested for further improvement of the oscillator performance.

Upconversion nanoparticles (UCNPs) are well-known for their high efficiency, photostability, near-infrared excitation, and ability to estimate temperature through ratiometric imaging of two thermally coupled fluorescence bands. This work demonstrates the feasibility of volumetric temperature mapping in internal biological systems using light-sheet fluorescence microscopy and lipid-coated UCNPs as nanothermometry markers. This approach enables real-time thermal mapping with both high spatial and temporal resolution at the cellular and subcellular levels. To validate the method, we performed 3D temperature imaging on fixed Caenorhabditis elegans (C. elegans) after UCNP ingestion. The proposed technique represents a cutting-edge method for accurate 3D analysis of temperature-driven biological processes. It holds significant potential for applications in living organisms, offering a non-invasive tool to monitor intracellular and organ-specific temperature dynamics.

Superparamagnetic iron oxide nanoparticles (SPIONs) offer promising applications in nanomedicine due to their appealing properties. Their magnetic and magnetic hyperthermia properties are considered as relevant tools for low invasive cancer therapeutic applications. In this work, we report on the synthesis of polyhedral core-shell SPIONs. Their size was tuned to improve their magnetic properties. Furthermore, by hybridizing into a core-shell inorganic/inorganic structure, the nanoparticles can achieve significantly improved magnetic-to-thermal energy conversion efficiency (at least tenfold). The designed core NPs are composed of a Zn_0.4Fe_2.6O₄ core and a MnFe₂O₄ shell. Their size and morphology were determined by transmission electron microscopy, Fourier-transform infrared spectroscopy was used to investigate their chemical composition. The iron oxide phase was confirmed by Mössbauer analysis, and the magnetic properties were studied to select the ideal size for magnetic hyperthermia application.

In the ballistic regime at finite temperatures, the proximity effect diminishes following an exponential pattern; however, at low or zero temperatures, this transition alters to a decay characterized by a power law with a dimensionality-dependent exponent. Here, we extend the current understanding of the proximity effect by exploring the role of normal metal-superconductor (NS) junction geometry in altering the spatial propagation of the superconducting order. Specifically, we demonstrate that geometric factors, such as interface curvature, significantly affect the decay exponent of the Cooper pair wave function, with negative curvature increasing the proximity range exponent and positive curvature shortening it. Furthermore, we discuss how the geometry of the NS interface governs the transparency of the clean NS junction and thus influences the proximity effect. These results deepen our understanding of how geometry and the proximity effect interact, which is important for the design and optimization of superconducting hybrid devices.

Solvated supramolecular hydrogels present unique challenges in nanoscale morphological characterization because of their fragile fibrous nature and low concentration of the solid component. In this study, imidazolium-based hydrogels containing either diketopyrrolopyrrole (DPP) or zinc(II) phthalocyanine (ZnPc) fluorophores were imaged using confocal laser scanning microscopy (CLSM) of fully solvated gels and cryogenic scanning electron microscopy (cryo-SEM) was used to observe the corresponding xerogels. The DPP@Gel systems exhibit strong fluorescence and are effectively imaged using CLSM, with fibre morphologies that closely correlate with those seen with cryo-SEM. In contrast, the analogous imidazolium gel system containing a sulfonated zinc phthalocyanine (ZnPc@Gel) yields poor CLSM images because of the relatively weak emission and sample disruption during compression, whereas cryo-SEM enables clear visualization of the native fibrous network. These results demonstrate the complementary nature of CLSM and cryo-SEM and highlight the value of cryo-SEM as a very useful tool for imaging soft nanomaterials with low fluorescence or limited optical contrast.