2,209 research outputs found
Author Correction: Casimir forces exerted by epsilon-near-zero hyperbolic materials (Scientific Reports, (2020), 10, 1, (16831), 10.1038/s41598-020-73995-0)
No full textIn the original version of this Article, Igor S. Nefedov was incorrectly affiliated with “Saratov State University, Astrakhanskaya 83, Saratov, Russian Federation, 410012”. The correct affiliation is listed below: Peoples’ Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya St., Moscow 117198, Russia. This error has now been corrected in the HTML and PDF versions of the Article. © 2020, The Author(s)
PKE–Nefedov*: plasma crystal experiments on the International Space Station
No full textAbstract. The plasma crystal experiment PKE–Nefedov, the first basic science experiment on the International Space Station (ISS), was installed in February 2001 by the first permanent crew. It is designed for long-term investigations of complex plasmas under microgravity conditions. ‘Complex plasmas ’ contain ions, electrons, neutrals and small solid particles—normally in the micrometre range. These microparticles obtain thousands of elementary charges and interact with each other via a ‘screened ’ Coulomb potential. Complex plasmas are of special interest, because they can form liquid and crystalline states (Thoma
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PKE-Nefedov*: Plasma crystal experiments on the International Space Station
No full textThe plasma crystal experiment PKE-Nefedov, the first basic science experiment on the International Space Station (ISS), was installed in February 2001 by the first permanent crew. It is designed for long-term investigations of complex plasmas under microgravity conditions. 'Complex plasmas' contain ions, electrons, neutrals and small solid particles - normally in the micrometre range. These microparticles obtain thousands of elementary charges and interact with each other via a 'screened' Coulomb potential. Complex plasmas are of special interest, because they can form liquid and crystalline states (Thomas et al 1994 Phys. Rev. Lett. 73 652-5, Chu and I 1994 Phys. Rev. Lett. 72 4009-12) and are observable at the kinetic level. In experiments on Earth the microparticles are usually suspended against gravity in strong electric fields. This creates asymmetries, stresses and pseudo-equilibrium states with sufficient free energy to readily become unstable. Under microgravity conditions the microparticles move into the bulk of the plasma (Morfill et al 1999 Phys. Rev. Lett. 83 1598), experiencing much weaker volume forces than on Earth. This allows investigations of the thermodynamics of strongly coupled plasma states under substantially stress-free conditions. In this first paper we report our results on plasma crystals, in particular the first experimental observations of bcc lattice structures
THERMAL CHARACTERIZATION OF CARBON NANOTUBES BY PHOTOTHERMAL TECHNIQUES
No full textHeat transport at nanoscale is of importance for many nanotech- nology applications. The request to reduce the size of electronic devices and integrated micro/ nano-electro-mechanical systems provides the main driving force behind the scientific research and technological advancement in nanotechnology. It is now widely accepted that the thermal management in nanosize devices becomes fundamental as the size of the device reduces. Thermal conduction in nanostructures plays a critical role in controlling the performances and stability of nanodevices
Nondestructive characterization of Carbon Nanotubes by Photothermal Techniques
No full textCarbon nanotubes (CNT) are multifunctional materials commonly used in a large number of applications in electronics, sensors, nanocomposites, thermal management, actuators, energy storage and conversion, and drug delivery.
Despite recent important advances in the development of CNT purity assessment tools and atomic resolution imaging of individual nanotubes by scanning tunnelling microscopy and high-resolution transmission electron microscopy, the macroscale assessment of the overall surface qualities of commercial CNT materials remains a great challenge. The lack of quantitative measurement technology to characterize and compare the surface qualities of bulk manufactured and engineered CNT materials has negative impacts on the reliable and consistent nanomanufacturing of CNT products
In this paper we show how photothermal and photoacoustic techniques represent useful non-destructive tools to study the thermal properties of carbon nanotubes films. The photoacoustic spectroscopy (PAS) is used for a direct measurement of the absorbance spectra of CNT showing many advantages with respect to the standard optical spectra measurements which are usually affected by relevant scattering phenomena. We applied PAS in the UV/VIS range from 250 to 650 nm by using 400 W Arc Xe lamp. On the other side photothermal radiometry (PTR) has been applied by using an Ar++ pump laser beam, modulated at a frequency in the range 1Hz -100 kHz, and a MCT infrared detector, in order to measure the effective thermal parameters, the IR emission properties from CNT thin films, and evaluate the average thermal boundary resistances at the film/bulk interface.
We investigated two set of CNT; in the first group the nanostructures are aligned (“forest”) and deposited onto a silicon substrate. The diameter of the nanotubes ranges from 20-50nm, and the total thickness of the CNT film ranges from m tom. In the second group the CNT are randomly oriented in plane, and the CNT film is deposited on different transparent substrate (PET and quartz).
Experimental results show how both PAS and PTR represent an excellent tool for quantitative measurement of the thermal properties of CNT thin films
THERMAL CHARACTERIZATION OF CARBON NANOTUBES BY PHOTOTHERMAL TECHNIQUES
No full textCarbon nanotubes (CNT) are multifunctional materials commonly used in a large number of applications in electronics, sensors, nanocomposites, thermal management, actuators, energy storage and conversion, and drug delivery.
Despite recent important advances in the development of CNT purity assessment tools and atomic resolution imaging of individual nanotubes by scanning tunnelling microscopy and high-resolution transmission electron microscopy, the macroscale assessment of the overall surface qualities of commercial CNT materials remains a great challenge. The lack of quantitative measurement technology to characterize and compare the surface qualities of bulk manufactured and engineered CNT materials has negative impacts on the reliable and consistent nanomanufacturing of CNT products
In this paper we show how photothermal and photoacoustic techniques represent useful non-destructive tools to study the thermal properties of carbon nanotubes films. The photoacoustic spectroscopy (PAS) is used for a direct measurement of the absorbance spectra of CNT showing many advantages with respect to the standard optical spectra measurements which are usually affected by relevant scattering phenomena. We applied PAS in the UV/VIS range from 250 to 650 nm by using 400 W Arc Xe lamp. On the other side photothermal radiometry (PTR) has been applied by using an Ar++ pump laser beam, modulated at a frequency in the range 1Hz -100 kHz, and a MCT infrared detector, in order to measure the effective thermal parameters, the IR emission properties from CNT thin films, and evaluate the average thermal boundary resistances at the film/bulk interface.
We investigated two set of CNT; in the first group the nanostructures are aligned (“forest”) and deposited onto a silicon substrate. The diameter of the nanotubes ranges from 20-50nm, and the total thickness of the CNT film ranges from 70m to 240m. In the second group the CNT are randomly oriented in plane, and the CNT film is deposited on different transparent substrate (PET and quartz).
Experimental results show how both PAS and PTR represent an excellent tool for quantitative measurement of the thermal properties of CNT thin films
Iodine incorporation into polymeric films investigated by angle-resolved XPS
No full textDistribution of elements into subsurface layers (up to 120 angstrom thickness) of polyphenylacetylene (PPA) films doped with I2 vapour has been determined by X-ray photoelectron spectroscopy data using a unique numerical technique. Concentration of incorporated iodine has been shown to increase with exposure time; the concentration profiles are dome-shaped and iodine does not penetrate much into the bulk of PPA films, even when exposed to I2 vapours for 1 h. The depth of the layer corresponding to maximum iodine concentration is directly proportional to the iodine exposure time. The non-homogeneous distribution of the doping species in the polymer may be responsible for the low conductivity observed for heterogeneously doped PPA films
A study of capacitance-voltage characteristics of amorphous carbon multilayer nanostructures
No full textDark and illuminated capacitance–voltage (C–V) characteristics and admittance measurements were carried out on multilayer carbon structures.The latter were produced by depositing ultrathin amorphous carbon layers with different optical band gaps on a monocrystalline boron-doped silicon substrate.The carbon layers were grown either by magnetron sputtering (MS) of a graphite target in argon or by plasma ion beam deposition (IBD) in cyclohexane.The structures were characterised by X-ray reflectivity (XRR). With respect to their electrical properties, it was shown that light strongly affects both the C–V-characteristics and the admittance.The results were interpreted in terms of the energy levels in these amorphous carbon multilayer structure
Thermal Characterization of Carbon Nanotubes by Photothermal Techniques
No full textCarbon nanotubes (CNTs) are multifunctional materials commonly used in
a large number of applications in electronics, sensors, nanocomposites, thermal management,
actuators, energy storage and conversion, and drug delivery. Despite recent
important advances in the development of CNT purity assessment tools and atomic
resolution imaging of individual nanotubes by scanning tunnelling microscopy and
high-resolution transmission electron microscopy, the macroscale assessment of the
overall surface qualities of commercial CNT materials remains a great challenge. The
lack of quantitative measurement technology to characterize and compare the surface
qualities of bulk manufactured and engineered CNT materials has negative impacts
on the reliable and consistent nanomanufacturing of CNT products. In this paper it is
shown how photoacoustic spectroscopy and photothermal radiometry represent useful
non-destructive tools to study the optothermal properties of carbon nanotube thin
films
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