Search results for "nanostructure"
showing 10 items of 792 documents
Electrodeposited nickel–zinc alloy nanostructured electrodes for alkaline electrolyzer
2022
Abstract Over the last decade, as a consequence of the global decarbonization process, the interest towards green hydrogen production has drastically increased. In particular a substantial research effort has focused on the efficient and affordable production of carbon-free hydrogen production processes. In this context, the development of more efficient electrolyzers with low-cost electrode/electrocatalyst materials can play a key role. This work, investigates the fabrication of electrodes of nickel-zinc alloys with nanowires morphology cathode for alkaline electrolyzers. Electrodes are obtained by the simple method of template electrosynthesis that is also inexpensive and easily scalable.…
Syntheses and Characterizations of Functional Polycyclic Aromatic Hydrocarbons and Graphene Nanoribbons
2020
In contrast to zero-bandgap graphene, nanostructures of graphene, such as graphene quantum dots (GQDs) and graphene nanoribbons (GNRs) have open bandgaps due to the quantum confinement effect, and are thus highly interesting for semiconductor applications, for example in nanoelectronics and optoelectronics. While conventional methods cannot provide GQDs and GNRs with chemically precise structures, large polycyclic aromatic hydrocarbon (PAH) molecules can be regarded as atomically precise GQDs. Moreover, extension of the PAH synthesis can lead to GNRs with well-defined chemical structures. In this account, we summarize our recent achievements in our synthetic exploration of PAHs and GNRs wit…
Zinc Oxide Nanowires on Printed Circuit Boards
2015
Printed circuit boards (PCBs), which are widely used for the fabrication of electronic circuits, can only withstand rather low temperatures. For this reason, the fabrication of high-density, long ZnO nanostructures on PCBs still remains a complex task. In fact, in absence of a seed-layer, whose annealing would require high temperatures, solution-growth methods only allow to synthesize low-density arrays of nanowires. Here we evaluate methods for overcoming this issue and, as a prototype, demonstrate a simple displacement sensor.
Constructing Large 2D Lattices Out of DNA-Tiles.
2021
The predictable nature of deoxyribonucleic acid (DNA) interactions enables assembly of DNA into almost any arbitrary shape with programmable features of nanometer precision. The recent progress of DNA nanotechnology has allowed production of an even wider gamut of possible shapes with high-yield and error-free assembly processes. Most of these structures are, however, limited in size to a nanometer scale. To overcome this limitation, a plethora of studies has been carried out to form larger structures using DNA assemblies as building blocks or tiles. Therefore, DNA tiles have become one of the most widely used building blocks for engineering large, intricate structures with nanometer precis…
A potential solution to avoid overdose of mixed drugs in the event of Covid-19: Nanomedicine at the heart of the Covid-19 pandemic.
2021
Since 2020, the world is facing the first global pandemic of 21st century. Among all the solutions proposed to treat this new strain of coronavirus, named SARS-CoV-2, the vaccine seems a promising way but the delays are too long to be implemented quickly. In the emergency, a dual therapy has shown its effectiveness but has also provoked a set of debates around the dangerousness of a particular molecule, hydroxychloroquine. In particular, the doses to be delivered, according to the studies, were well beyond the acceptable doses to support the treatment without side effects. We propose here to use all the advantages of nanovectorization to address this question of concentration. Using quantum…
Geometrical control of pure spin current induced domain wall depinning.
2017
[EN] We investigate the pure spin-current assisted depinning of magnetic domain walls in half ring based Py/Al lateral spin valve structures. Our optimized geometry incorporating a patterned notch in the detector electrode, directly below the Al spin conduit, provides a tailored pinning potential for a transverse domain wall and allows for a precise control over the magnetization configuration and as a result the domain wall pinning. Due to the patterned notch, we are able to study the depinning field as a function of the applied external field for certain applied current densities and observe a clear asymmetry for the two opposite field directions. Micromagnetic simulations show that this …
Biosensors for the determination of SARS-CoV-2 virus and diagnosis of COVID-19 infection
2022
Monitoring and tracking infection is required in order to reduce the spread of the coronavirus disease 2019 (COVID-19), induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To achieve this goal, the development and deployment of quick, accurate, and sensitive diagnostic methods are necessary. The determination of the SARS-CoV-2 virus is performed by biosensing devices, which vary according to detection methods and the biomarkers which are inducing/providing an analytical signal. RNA hybridisation, antigen-antibody affinity interaction, and a variety of other biological reactions are commonly used to generate analytical signals that can be precisely detected using electro…
Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties
2011
We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical…
Effect of Mechanoactivation on Interfacial Interaction in Metal/Oxide Systems
2006
Properties of interfaces in solid state metal/oxide joints (Al/SiO2, Al/MgO, Al/glass, Mg/MgO, Mg/SiO2, In/glass etc.) are reported. The interfaces were formed by plastic deformation of metal on the oxide surface at room temperature. Their structure, chemical composition, and micromechanical properties were studied by the AFM, XRD, SIMS, optical microscopy, and precision microindentation techniques. A noticeable adhesion was observed for metals with high affinity for oxygen and only in the regions of the maximum shear stress. Formation of an interfacial reaction zone with an oxygen concentration gradient is detected. In this zone metals are nanostructured and noticeably hardened. The effect…
Inorganic/organic hybrid nanoparticles synthesized in a two-step radiation-driven process
2022
In this work, we have synthesized inorganic-organic hybrid nanoparticles via radiation synthesis of inorganic nanoparticles (Ag and CeO2) in aqueous dispersions containing radiation-synthesized poly(N-vinyl pyrrolidone) (PVP) nanogels (NG). The experiments show that there are strong interactions between the inorganic precursors (Ag+ and Ce3+) and the nanogel prior to irradiation. The two hybrid systems (Ag/NG and CeO2/NG) were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD confirms the formation of crystalline Ag and CeO2. TEM reveals that the inorganic nanoparticles are evenly distributed in/on the nanogel. Both XRD and TEM show that size of the…