Search results for "CONTACT"

Improved hydrophobicity of inorganic–organic hybrid mesoporous silica with cage-like pores

2013

International audience; Hydrophobic ordered mesoporous silica particles with cage-like pores (SBA-1 type) were prepared through co-condensation of phenyltriethoxysilane (PhTES) and tetraethylorthosilicate (TEOS) at different TEOS/PhTES molar ratios. It is shown that the hydrophobic character of the particles is enhanced by increasing the phenyl loading (decreasing the TEOS/PhTES molar ratio) and that it could be further enhanced by subsequent trimethylsilyl (TMS) grafting on remaining silanol groups (TMS-PhSBA-1 sample). This increase of hydrophobicity has been evidenced on the internal surface (mesoporosity) of the particles using water adsorption and, on the external surface of the partic…

Series expansion for the effective conductivity of a periodic dilute composite with thermal resistance at the two-phase interface

2019

We study the asymptotic behavior of the effective thermal conductivity of a periodic two-phase dilute composite obtained by introducing into an infinite homogeneous matrix a periodic set of inclusions of a different material, each of them of size proportional to a positive parameter ?. We assume that the normal component of the heat flux is continuous at the two-phase interface, while we impose that the temperature field displays a jump proportional to the normal heat flux. For ? small, we prove that the effective conductivity can be represented as a convergent power series in ? and we determine the coefficients in terms of the solutions of explicit systems of integral equations.

Optical quality comparison among different Boston contact lens materials.

2014

BACKGROUND The aim was to assess the optical quality of four Boston contact lens materials with an optical device based on Schlieren interferometry. METHODS The NIMO TR1504 (Lambda-X, Nivelles, Belgium) was used to measure higher-order aberrations and their corresponding root mean square values of four different rigid gas permeable contact lenses made from four different Boston materials: EO, ES, XO and XO2 . For each lens, 30 measurements were performed with two optical apertures: 3.0 mm and 6.0 mm. The modulation transfer function, point spread function, Strehl ratio and a simulation of the image provided by the lens were computed from the Zernike coefficients measured up to the fourth or…

Environmental chamber for an atomic force microscope.

2007

A commercial atomic force microscope (AFM), originally designed for operation in ambient conditions, was placed inside a compact aluminum chamber, which can be pumped down to high vacuum levels or filled with a desired gaseous atmosphere, including humidity, up to normal pressure. The design of this environmental AFM is such that minimal intrusion is made to the original setup, which can be restored easily. The performance inside the environmental chamber is similar to the original version.

Spatiotemporal colorimetry to reveal electrochemical kinetics of poly(o-toluidine) films along ITO surface

2018

Abstract Sheet resistance of transparent conducting electrodes can affect dramatically the electrochromic response of surface confined active species in any electrochromic device. The generated gradient of effective potential on the electrode surface has a direct impact on the electrochemical kinetics of these species. In this work, the electrochromic poly (o-toluidine) (POT) film, a derivative polyaniline, was deposited along a narrow, long transparent indium tin oxide (ITO) supporting electrode with a sheet resistivity of 30 Ω cm−1. This configuration was used as a model to simulate a surface electrical conduction from the external metallic contact to the opposite extreme of ITO with an i…

Model network architectures in vitro on extracellular recording systems using microcontact printing

2001

A PDMS stamp is used to transfer a synthetic peptide in a given pattern to any suitable surface. Using this method two-dimensional neuronal model networks could be formed on glass substrates as well as on electronic devices and adjusted to the given microelectronic structure. The present work focuses on the mechanism of neurite guidance under simplified in vitro conditions, using in vitro guidance cues and outline the incorporation of these interfacial methods into microelectronic sensor devices.

2017

Dielectric loaded surface plasmon waveguides (DLSPPWs) comprised of polymer ridges deposited on top of CMOS compatible metal thin films are investigated at telecom wavelengths. We perform a direct comparison of the properties of copper (Cu), aluminum (Al), titanium nitride (TiN) and gold (Au) based waveguides by implementing the same plasmonic waveguiding configuration for each metal. The DLSPPWs are characterized by leakage radiation microscopy and a fiber-to-fiber configuration mimicking the cut-back method. We introduce the ohmic loss rate (OLR) to analyze quantitatively the properties of the CMOS metal based DLSPPWs relative to the corresponding Au based waveguides. We show that the Cu,…

Impact of contact resistance on the electrical properties of MoS2 transistors at practical operating temperatures

2017

Molybdenum disulphide (MoS2) is currently regarded as a promising material for the next generation of electronic and optoelectronic devices. However, several issues need to be addressed to fully exploit its potential for field effect transistor (FET) applications. In this context, the contact resistance, RC, associated with the Schottky barrier between source/drain metals and MoS2 currently represents one of the main limiting factors for suitable device performance. Furthermore, to gain a deeper understanding of MoS2 FETs under practical operating conditions, it is necessary to investigate the temperature dependence of the main electrical parameters, such as the field effect mobility (μ) an…

PANI-Based Wearable Electrochemical Sensor for pH Sweat Monitoring

2021

Nowadays, we are assisting in the exceptional growth in research relating to the development of wearable devices for sweat analysis. Sweat is a biofluid that contains useful health information and allows a non-invasive, continuous and comfortable collection. For this reason, it is an excellent biofluid for the detection of different analytes. In this work, electrochemical sensors based on polyaniline thin films deposited on the flexible substrate polyethylene terephthalate coated with indium tin oxide were studied. Polyaniline thin films were abstained by the potentiostatic deposition technique, applying a potential of +2 V vs. SCE for 90 s. To improve the sensor performance, the electronic…

Morphological and Chemical Evolution of Gradually Deposited Diamond-Like Carbon Films on Polyethylene Terephthalate: From Subplantation Processes to …

2016

Diamond-like carbon (DLC) films on polyethylene terephthalate (PET) are nowadays intensively studied composites due to their excellent gas barrier properties and biocompatibility. Despite their applicative features being highly explored, the interface properties and structural film evolution of DLC coatings on PET during deposition processes are still sparsely investigated. In this study two different types of DLC films were gradually deposited on PET by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) using acetylene plasma. The surface morphology of the deposited samples has been analyzed by atomic force microscopy (AFM). Their chemical composition was investigated by …