Search results for "electronics"
showing 10 items of 4340 documents
“Compatibilization” through Elongational Flow Processing of LDPE/PA6 Blends
2018
Polyamide/polyolefin blends have gained attention from the academia and the industry for several years. However, in order to optimize their properties, some drawbacks such as chemical incompatibility must be adequately overcome. This can be done by adding suitable compatibilizers. On the other hand, it is less known that suitable processing techniques may also lead to significant results. In a previous work on a low-density polyethylene/polyamide 6 (LDPE/PA6) blend, we found that the orientation due to elongational flow processing conditions could lead to an unexpected brittle&ndash
On the Phase Separation in n-Type Thermoelectric Half-Heusler Materials
2018
Half-Heusler compounds have been in focus as potential materials for thermoelectric energy conversion in the mid-temperature range, e.g., as in automotive or industrial waste heat recovery, for more than ten years now. Because of their mechanical and thermal stability, these compounds are advantageous for common thermoelectric materials such as Bi 2 Te 3 , SiGe, clathrates or filled skutterudites. A further advantage lies in the tunability of Heusler compounds, allowing one to avoid expensive and toxic elements. Half-Heusler compounds usually exhibit a high electrical conductivity σ , resulting in high power factors. The main drawback of half-Heusler compounds is their high lattice th…
Deformation and failure of MXene nanosheets
2020
This work is aimed at the development of finite element models and prediction of the mechanical behavior of MXene nanosheets. Using LS-Dyna Explicit software, a finite element model was designed to simulate the nanoindentation process of a two-dimensional MXene Ti3C2Tz monolayer flake and to validate the material model. For the evaluation of the adhesive strength of the free-standing Ti3C2Tz-based film, the model comprised single-layered MXene nanosheets with a specific number of individual flakes, and the reverse engineering method with a curve fitting approach was used. The interlaminar shear strength, in-plane stiffness, and shear energy release rate of MXene film were predicted using th…
Evolution of the sp2 content and revealed multilayer growth of amorphous hydrogenated carbon (a-C:H) films on selected thermoplastic materials
2017
Amorphous hydrogenated carbon (a-C:H) films were gradually deposited on high-density polyethylene (HDPE), polyethylene terephthalate (PET) and polyoxymethylene (POM) via an indirect (f-type) and a direct (r-type) plasma-enhanced chemical vapor deposition (PECVD) process with acetylene plasma. The surface morphologies of the thicker r-depositions on the three different thermoplastics have been analyzed by atomic force microscopy (AFM) at varying micrometer scales. Absorbance spectroscopy has been used to characterize the optical properties of all coatings. Intrinsic stress release phenomena are revealed on thicker layers through the detection of characteristic surface corrugations. Based on …
Wavelength-selective directional coupling with dielectric-loaded plasmonic waveguides
2009
International audience; We consider wavelength-selective splitting of radiation using directional couplers (DCs) formed by dielectric-loaded surface-plasmon-polariton waveguides (DLSPPWs). The DCs were fabricated by depositing subwavelength-sized polymer ridges on a gold film using large-scale UV photolithography and characterized at telecommunications wavelengths with near-field microscopy. We demonstrate a DLSPPW-based 45-mu m-long DC comprising 3 mu m offset S bends and 25-mu m-long parallel waveguides that changes from the "through" state at 1500 nm to 3 dB splitting at 1600 nm, and show that a 50.5-mu m-long DC should enable complete separation of the radiation channels at 1400 and 162…
Preparation of conductive PDDA/(PEDOT:PSS) multilayer thin film: influence of polyelectrolyte solution composition.
2014
Abstract Self-assembled multilayer films made of PEDOT:PSS poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) and PDDA poly(diallyldimethylammonium chloride) were prepared using layer-by-layer method. In order to modify the growth regime of the multilayer, to fabricate an electrical conductive film and to control its thickness, the effects of pH, type of electrolyte, ionic strength and polyelectrolyte concentration were investigated. Optical reflectometry measurements show that the pH of the solutions has no effect on the film growth while the adsorbed amount increases more rapidly when BaCl2 is used instead of NaCl as electrolyte. An increase in the ionic strength (with NaCl) induces…
Measurement of UV-induced absorption and scattering losses in photosensitive fibers
2018
UV-assisted fabrication of gratings using photosensitive fibers is a well-established technique, based on the UV-induced permanent modification of the refractive index of the fiber material. As a result, the absorption coefficient is also changed. Here, we exploit the thermal sensitivity of whispering gallery mode resonances of the fiber itself to measure the profile of the heating along an irradiated fiber versus the input power and for different UV radiation intensities. Our technique allows discriminating between the absorption and scattering contributions to the overall losses, by comparing the results obtained with our technique with direct transmission measurements. Different photosen…
Surface-Specific Spectroscopy of Water at a Potentiostatically Controlled Supported Graphene Monolayer
2019
Knowledge of the structure of interfacial water molecules at electrified solid materials is the first step toward a better understanding of important processes at such surfaces, in, e.g., electrochemistry, atmospheric chemistry, and membrane biophysics. As graphene is an interesting material with multiple potential applications such as in transistors or sensors, we specifically investigate the graphene–water interface. We use sum-frequency generation spectroscopy to investigate the pH- and potential-dependence of the interfacial water structure in contact with a chemical vapor deposited (CVD) grown graphene surface. Our results show that the SFG signal from the interfacial water molecules a…
Some aspects of the MOCVD growth of ZnO on sapphire using tert-butanol
2002
The growth of ZnO on (0001) sapphire substrates using metalorganic chemical vapor deposition is reported. Diethylzinc and tertiarybutanol were used, respectively, as zinc and oxygen sources. Growth conditions are detailed such as the substrate temperature and the precursors partial pressures. The influence of the cleanness state of the MOCVD silica reactor is emphasized, since it modifies both layer quality and crystalline orientation, and since it also affects growth process steps like sapphire thermal treatment and buffer layer deposition. ZnO epitaxial layers are characterised by scanning electron microscopy (SEM) to assess the surface orientation and morphology, X-ray diffraction (XRD) …
Corrosion behaviour of galvanized steel studied by electrochemical microprobes applied on low-angle cross sections
2018
Abstract The combined use of the microcapillary cell (MEC) and scanning vibrating electrode technique (SVET) and low-angle cross sections was employed to elucidate the role of each coating region on the protection of the cut-edge corrosion of galvanized steels. Different compounds are involved in the blocking action of the corrosion products: Zincite (ZnO) on the steel substrate, hydrozincite (Zn5(OH)6(CO3)2) at the coating/steel interface, and Simonkolleite (Zn5(OH)8Cl2) and ZnO on the different coating regions in different proportions. The coating surface is also active at the initial stage and during long-term protection and thus, must be considered in experimental simulation of the cut-…