Repository of University of Nova Gorica

Search the repository
A+ | A- | Help | SLO | ENG

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


1 - 3 / 3
First pagePrevious page1Next pageLast page
1.
System and method for continuous wave low power laser based synthesis of metal nano particles : patent certificate IN 512589, 2024-02-20
Sankaranarayana Iyer Sankararaman, Mohanachandran Nair Sindhu Swapna, Abdul Rahim Sajeela Beevi Ashik, Ramachandran Nair Amba Devi Krishnanunni, Vadakkedathu Parameswaran Narayanan Nampoori, 2024, patent

Abstract: This disclosure relates to synthesis of metal nanoparticles (NPs). In particular, the invention relates to methods of synthesizing metal nanoparticles using Laser. The invention relates to Laser assisted synthesis of metal nanoparticles using continuous wave low laser power in a liquid medium. The system [100] for synthesis of metal nanoparticles, comprises of a laser source [101], a mechanical chopper [102], a lens [103], a target metal [104], a liquid medium [106] and a heat source [107]. Additionally the invention relates to laser assisted synthesis of metal nanoparticles with silver as the metal target and water as the liquid medium. The NPs produced are characterized by UV-Visible spectrophotometer, Field-emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Spectroscopy (EDS), and Transmission Electron Microscopy (TEM).Figure 1.
Keywords: cw laser, nanoparticle, method
Published in RUNG: 26.02.2024; Views: 249; Downloads: 1
URL Link to file
This document has many files! More...

2.
Photoacoustics - A nondestructive evaluation technique for thermal and optical characterisation of metal mirrors
Mohanachandran Nair Sindhu Swapna, NAMPOORI V P N, Sankararaman S, 2018, original scientific article

Abstract: Photoacoustic technique has emerged as a powerful tool for nondestructive evaluation and characterization. The high signal to noise ratio, sensitivity, and the least quantity of sample required make the technique suitable for wide range of applications. The intensity modulated laser beam focused on to the sample in the photoacoustic cell generates acoustic waves. Analysis of the acoustic signal enables the measurement of thermal and optical properties of the material. In the present work, the photoacoustic technique has been extended to find the thermal diffusivity and to demonstrate how the technique can be used for measuring optical reflection coefficient of a precious metal mirror—Aranmula mirror. The mirror being metal with high reflection coefficient, it finds application in optical instrumentation. The mirror is subjected to morphological characterization by atomic force microscopy and field emission scanning electron microscopy. The elemental and structural characterizations are done by energy dispersive x-ray spectroscopy, X-ray dot mapping, and X-Ray diffraction analysis. The fractal dimension of the particle distribution over the surface provides information about the surface roughness. The box-counting and power spectral fractal dimensions are found to be around 1.63 and 1.65 respectively.
Keywords: Photoacoustics, Nondestructive evaluation, Aranmula metal mirror, Reflectivity
Published in RUNG: 30.06.2022; Views: 1331; Downloads: 0
This document has many files! More...

3.
Ultralow duty cycle chopper instigated low power continuous wave laser assisted synthesis of silver nanoparticles : a novel approach
Mohanachandran Nair Sindhu Swapna, Abdul Rahim Sajeela Beevi Ashik, Ramachandran Nair Amba Devi Krishnanunni, Vadakkedathu Parameswaran Narayanan Nampoori, Sankaranarayana Iyer Sankararaman, 2020, original scientific article

Abstract: This paper is the first report of advancement in the drastic reduction of the laser power density from 105 to 7.5 W/cm2 for the synthesis of silver nanoparticles (SNPs) using a low power (60 mW) continuous-wave (cw) laser and a specially designed ultralow duty cycle (3%) optical chopper wheel for modulating the laser beam at low frequencies (2 Hz). The target is irradiated by keeping it in a liquid medium at 40–60 °C to produce quantum dots to SNPs of size less than 40 nm. The UV-visible spectroscopic and electron microscopic analyses confirm the formation of quantum dots and SNPs of size-dependent bandgap energy varying from 1.92 to 2.37 eV. The photoluminescence studies not only support the above observations but also reveal the blue emission upon UV excitation through the chromaticity diagram. The proposed greener approach using the low power cw laser is cost-effective when compared with the high-power laser-assisted synthesis of SNPs reported until now.
Keywords: cw laser, silver nanoparticle, ultralow duty cycle, chopper
Published in RUNG: 30.06.2022; Views: 1133; Downloads: 25
URL Link to full text
This document has many files! More...

Search done in 0.02 sec.
Back to top