Search results for "Optical"

The Influence of Nanoparticle Shape on Protein Corona Formation

2020

Nanoparticles have become an important utility in many areas of medical treatment such as targeted drug and treatment delivery as well as imaging and diagnostics. These advances require a complete understanding of nanoparticles' fate once placed in the body. Upon exposure to blood, proteins adsorb onto the nanoparticles surface and form a protein corona, which determines the particles' biological fate. This study reports on the protein corona formation from blood serum and plasma on spherical and rod‐shaped nanoparticles. These two types of mesoporous silica nanoparticles have identical chemistry, porosity, surface potential, and size in the y ‐dimension, one being a sphere and the other a …

Room temperature synthesis of lanthanum phosphates with controlled nanotexture as host for Ln(III) through the Epoxide Route

2022

AbstractHerein, the Epoxide Route, a one-pot room temperature alkalinization method based on the reaction between a nucleophile and an epoxide, has been employed to synthesize LaPO4 in the form of a Rhabdophane phase. The intrinsic features of this synthetic approach allow the reaction to be followed by pH monitoring, making possible the identification of the different precipitation steps involved in the formation of the solid. Once demonstrated the effectiveness of this chemical methodology, the size and shape of the LaPO4 particles were controlled by varying the identity and proportion of the organic co-solvents employed to perform the reaction. By these means, crystalline particles with …

FIBRE OPTICAL COUPLER SIMULATION BY COMSOL MULTIPHYSICS SOFTWARE

2022

Funding: The research has been supported by the European Regional Development Fund project No.1.1.1.1/18/A/068. The Institute of Solid State Physics, University of Latvia as a Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.

Photoluminescence properties of point defects in Ge-doped fibers and preforms

2008

International audience; The optical properties of Ge-related point defects are often the most important parameter for the performances of silica based optical fibers. On one side their presence is often detrimental for the light transmission, on the other side some defect typologies exhibit modifications under radiation exposure thus offering the peculiar property of photosensitivity that is exploited to build technologically relevant devices such as fiber Bragg gratings.

10-keV X-ray irradiation effects on phosphorus doped fibers and preforms: electron spin resonance and optical studies

2009

Charge Transport Mechanisms in Heavy-Ion Driven Leakage Current in Silicon Carbide Schottky Power Diodes

2016

Under heavy-ion exposure at sufficiently high reverse bias voltages silicon carbide (SiC) Schottky diodes are observed to exhibit gradual increases in leakage current with increasing ion fluence. Heavy-ion exposure alters the overall reverse current-voltage characteristics of these diodes, leaving the forward characteristics practically unchanged. This paper discusses the charge transport mechanisms in the heavy-ion damaged SiC Schottky diodes. A macro model, describing the reverse current-voltage characteristics in the degraded SiC Schottky diodes is proposed. peerReviewed

Effect of the Si doping on the properties of AZO/SiC/Si heterojunctions grown by low temperature pulsed laser deposition

2020

Abstract The structural and photoelectrical properties of Al-doped ZnO (AZO)/SiC/p-Si and AZO/SiC/n-Si heterojunctions, fabricated at low temperature by pulsed laser deposition, were investigated by means of a number of techniques. Raman analysis indicates that SiC layers have the cubic 3C-SiC phase, whilst X-ray diffraction measurements show that AZO films exhibit a hexagonal wurtzite structure, highly textured along the c-axis, with average crystallites size of 35.1 nm and lattice parameter c of 0.518 nm. The homogeneous and dense surface morphology observed by scanning electron microscopy was confirmed by atomic force microscopy images. Moreover, UV–Vis-NIR spectra indicated a high trans…

Amorphous silicon nanotubes

2017

In the following, the attention will be focused on the silicon nanotube (SiNTs) that is a highly desired form of silicon for its fundamental role in the miniaturization trend of the electronic devices. After a description of the properties and applications of SiNTs and their fabrication methods, the attention will be focused on chemical vapour deposition (CVD) template synthesis that is the most usual synthetic method for this material. Then, galvanic template synthesis will be described as a general method for the fabrication of different metals and oxides nanostructures, therefore the use of this technique for synthesizing SiNTs will be detailed. Characterization methods will be also desc…

Localized surface plasmon resonance in silver nanoparticles: Atomistic first-principles time-dependent density-functional theory calculations

2015

We observe using ab initio methods that localized surface plasmon resonances in icosahedral silver nanoparticles enter the asymptotic region already between diameters of 1 and 2 nm, converging close to the classical quasistatic limit around 3.4 eV. We base the observation on time-dependent density-functional theory simulations of the icosahedral silver clusters Ag$_{55}$ (1.06 nm), Ag$_{147}$ (1.60 nm), Ag$_{309}$ (2.14 nm), and Ag$_{561}$ (2.68 nm). The simulation method combines the adiabatic GLLB-SC exchange-correlation functional with real time propagation in an atomic orbital basis set using the projector-augmented wave method. The method has been implemented for the electron structure…

A fluorescence study of the loading and time stability of doxorubicin in sodium cholate/PEO-PPO-PEO triblock copolymer mixed micelles

2019

Abstract Hypothesis Doxorubicin hydrochloride (DX) is one of the most powerful anticancer agents though its clinical use is impaired by severe undesired side effects. DX encapsulation in nanocarrier systems has been introduced as a mean to reduce its toxicity. Micelles of the nonionic triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (PEO-PPO-PEO), are very promising carrier systems. The positive charge of DX confines the drug to the hydrophilic corona region of the micelles. The use of mixed micelles of PEO-PPO-PEO copolymers and a negatively charged bile salt should favour the solubilization of DX in the apolar core region of the micelles. Experiments We st…