Search results for " NANO"
showing 10 items of 10430 documents
High-Sensitivity Whispering Gallery Mode Humidity Sensor Based on Glycerol Microdroplet Volumetric Expansion
2021
We demonstrate a highly sensitive whispering gallery mode (WGM) relative humidity (RH) sensor based on a glycerol microdroplet. WGMs were excited using a 760 nm tunable semiconductor laser. We used free space coupling, which is effective when using a liquid resonator. A detailed analysis of different parameters influencing the sensor’s characteristics (sensitivity, hysteresis, resolution, stability, and temperature) is presented. The sensitivity of the sensor is one of the highest reported (2.85 nm/% RH in the range 50–70% RH with the resolution 1 × 10−4% RH). This type of humidity sensor has several advantages, such as high sensitivity, extended lifetime, good repeatability, and low cost, …
Effect of the extensional flow on the properties of oriented nanocomposite films for twist wrapping
2011
In this study, we examined the mechanical behavior of nanocomposite films based on polyethylene (PE) and pristine PE films. The films were prepared by film blowing and were then cold-drawn at low temperature. The experimental results show that cold drawing significantly enhanced the orientation; with increasing draw ratio (DR), the elastic modulus and tensile strength of the PE films strongly increased, particularly in the presence of the organoclay. To obtain polymeric films suitable for twist wrapping, the films must be sufficiently stiff so that no shrinkage or elastic recovery occur during or after twisting. The elongation at break and the yield strain sharply decreased with orientation…
Patterning of supported gold monolayers via chemical lift-off lithography
2017
The supported monolayer of Au that accompanies alkanethiolate molecules removed by polymer stamps during chemical lift-off lithography is a scarcely studied hybrid material. We show that these Au–alkanethiolate layers on poly(dimethylsiloxane) (PDMS) are transparent, functional, hybrid interfaces that can be patterned over nanometer, micrometer, and millimeter length scales. Unlike other ultrathin Au films and nanoparticles, lifted-off Au–alkanethiolate thin films lack a measurable optical signature. We therefore devised fabrication, characterization, and simulation strategies by which to interrogate the nanoscale structure, chemical functionality, stoichiometry, and spectral signature of t…
Prompt Determination of the Mechanical Properties of Industrial Polypropylene Sandwich Pipes
2021
A simple and prompt method to determine the mechanical properties of industrial multilayer extrusion polypropylene pipes for a gravity sewer network is suggested. The engineering formulas included for calculating the permissible thickness and relative position of a foam core in the pipes are based on a linear-elastic approximation and the rule of mixtures. The applicability of the approximation was justified experimentally during investigation of the effective tensile characteristics of single- and multilayer pipes and each layer specimen by using traditional tests and finite-element calculations. The results obtained were used to formulate engineering recommendations for calculations of th…
A new forum for upconversion research: The UPCON conference
2019
International audience; The Conference and Spring School on Properties, Design and Applications of Upconversion Nanomaterials (UPCON) provides a new forum for all experts and newcomers in the field of upconversion research. On the occasion of the second UPCON 2018 in Valencia (Spain), we are pleased to present a collection of 12 reviews and research articles that reflect recent advances in upconversion materials, their unique luminescent properties and many applications spanning from nanoscale thermometry to biomedicine.
Nanopartículas de upconversion: síntesis y aplicaciones
2017
En las últimas décadas la nanoquímica ha alcanzado gran interés debido a la importancia de desarrollar materiales únicos e innovadores en la escala nanométrica, específicamente nanopartículas. Las propiedades de los nanomateriales son diferentes de las de los respectivos materiales a gran escala, así la nanoquímica abre caminos innovadores en la ciencia para desarrollar materiales con nuevas propiedades y comportamientos novedosos. Las nanopartículas de upconversion (UCNP) están compuestas por nanocristales inorgánicos que contienen lantánidos, como NaYF4 codopados con cationes lantánidos (como Er3+, Yb3+, Tm3+…). Las UCNP tienen una excelente estabilidad química, térmica y lumínica, buena …
Sviluppo del metodo urea glass-route per la preparazione di nanoparticelle di Ce:YAG
2015
I materiali a base di yttrium aluminum garnet (YAG) drogato con ioni lantanidi hanno suscitato negli ultimi anni notevole interesse per le loro importanti applicazioni tecnologiche nel campo dei dispositivi optoelettronici quali laser, LED, display e scintillatori per i raggi X. In particolare, lo YAG drogato con ioni Ce(III) è utilizzato, in combinazione ai semiconduttori di nitruro di gallio (GaN) o indio e gallio (GaInN), per la realizzazione di LED a luce bianca1. Il miglioramento delle performance di questi dispositivi è vincolato all’ottimizzazione, in termini di proprietà, dei materiali che lo compongono. Una delle strategie consiste nel preparare nanoparticelle (np) di Ce:YAG con di…
Highly Sensitive Polarization Rotation Measurement through a High‐Order Vector Beam Generated by a Metasurface
2020
The precise determination of the polarization state of light is fundamental for a vast variety of applications in remote sensing, astronomy, optics and terahertz technology, to name just a few. Typically, polarization characterization is performed by using a combination of multiple optical devices such as beam splitters, polarizers, and waveplates. Moreover, to achieve high-precision, balanced photodetectors and lock-in amplifiers are employed, thus contributing to increasing system complexity. Here, a technique for polarization rotation measurements with a dynamic range of 180° and a sensitivity of about 10−2 degrees is realized using a properly designed metasurface. Such device generates …
Structure and dynamics in liquid bismuth and Bin clusters: A density functional study
2014
Density functional/molecular dynamics simulations with more than 500 atoms have been performed on liquid bismuth at 573, 773, 923, and 1023 K and on neutral Bi clusters with up to 14 atoms. There are similar structural patterns (coordination numbers, bond angles, and ring patterns) in the liquid and the clusters, with significant differences from the rhombohedral crystalline form. We study the details of the structure (structure factor, pair, and cavity distribution functions) and dynamical properties (vibration frequencies, diffusion constants, power spectra), and compare with experimental results where available. While the three short covalent bonds typical to pnictogens are characteristi…
Quantum coherent manipulation of spin information in molecular nanomagnets
2023
Los sistemas cuánticos de dos niveles basados en estados de espín, conocidos como ``qubits de espín'', son bloques prometedores para el desarrollo de tecnologías cuánticas. Entre las distintas plataformas físicas, los qubits de espín definidos en imanes de molécula única (SMM) son candidatos prometedores porque su estructura electrónica puede ajustarse fácilmente mediante ingeniería química (es decir, el Hamiltoniano de espín molecular puede modificarse con facilidad). Sin embargo, los qubits moleculares de espín generados en SMM se enfrentan a varios retos: coherencia cuántica frágil, control coherente insuficiente de los estados de espín y generación de entrelazamiento entre los qubits de…