Search results for "FREQUENCY"

RFID passive gas sensor integrating carbon nanotubes

2011

Carbon nanotube (CNT) composites are sensitive to the presence of gases due to their high surface-to-volume ratio and hollow structure that are well suited for gas molecule absorption and storage. Such sensing capability is here integrated with UHF RF identification (RFID) technology to achieve passive and low-cost sensors, remotely readable. CNT film (buckypaper) is used as a localized variable resistive load integrated into a tag antenna, which becomes able to transduce the presence of hazardous gas in the environment, ammonia in this case, into a change of its electromagnetic features. The dynamic range and the hysteresis of the radio sensor are investigated by simulations, equivalent ci…

RE: "RADIO-FREQUENCY RADIATION EXPOSURE FROM AM RADIO TRANSMITTERS AND CHILDHOOD LEUKEMIA AND BRAIN CANCER"

2008

Commentary on: Microwave Ablation for Metastatic Spinal Tumors

2021

Radiofrequency thermal ablation vs percutaneous ethanol injection for small hcc in cirrhosis:metanalysis of randomized controlled trials

2009

1. Am J Gastroenterol. 2009 Feb;104(2):514-24. Epub 2009 Jan 13. Radiofrequency thermal ablation vs. percutaneous ethanol injection for small hepatocellular carcinoma in cirrhosis: meta-analysis of randomized controlled trials. Orlando A, Leandro G, Olivo M, Andriulli A, Cottone M. Department of Medicine, Pneumology and Nutrition Clinic, V. Cervello Hospital, University of Palermo, Piazza Mameli 1, Palermo, Italy. ambrogiorlando@tiscali.it OBJECTIVES: Radiofrequency thermal ablation (RF) and percutaneous ethanol injection (PEI) have been employed in the treatment of small hepatocellular carcinoma (HCC) as curative treatments. The aim of the study was to review the available evidence compari…

La termoablazione nel trattamento delle neoplasie epatiche primitive e secondarie

2004

Radiofrequency thermoablation is a locoregional procedure based on the use of electromagnetic waves that induce movement and consequently the production of heat. This is the basis for the coagulative necrosis produced in the tissues. The method, experimented with and developed in the '90s, is today extensively used in the treatment of focal hepatic lesions, both primary and secondary. The factors that condition the procedure are related essentially to the characteristics of the tumours and to the possibility of obtaining a predictable area of necrosis that guarantees the radicality of the treatment. As regards primary neoplasms, it should be stressed that the treatment for hepatocellular ca…

Resection of verrucous squamous cell carcinoma of the nasal cavity using advanced radiofrequency

2008

Observation of octupole structures in radon and radium isotopes and their contrasting behavior at high spin

1997

Multinucleon transfer reactions have been used, for the first time, to populate high-spin bands of alternating parity states in {sup 218,220,222}Rn and {sup 222,224,226}Ra. The behavior of the angular momentum alignment with rotational frequency for the Rn isotopes is very different when compared with Ra and Th isotopes with N{approx}134, indicating a transition from octupole vibrational to stable octupole deformation. Throughout the measured spin range the values of {vert_bar}D{sub 0}/Q{sub 0}{vert_bar} remain constant for {sup 222}Ra and {sup 226}Ra and have a very small value for {sup 224}Ra, suggesting that the charge and mass distributions are not affected appreciably by rotations. {co…

The mass load effect on the resonant acoustic frequencies of colloidal semiconductor nanoplatelets

2016

Resonant acoustic modes of ultrathin CdS and CdSe colloidal nanoplatelets (NPLs) with varying thicknesses were probed using low frequency Raman scattering. The spectra are dominated by an intense band ascribed to the thickness breathing mode of the 2D nanostructures. The measured Raman frequencies show strong deviations with respect to the values expected for simple bare plates, all the more so as the thickness is reduced. The deviation is shown to arise from the additional mass of the organic ligands that are bound to the free surfaces of the nanoplatelets. The calculated eigen frequencies of vibrating platelets weighed down by the mass of the organic ligands are in very good agreement wit…

Interpretation of capacitance spectra and transit times of single carrier space-charge limited transport in organic layers with field-dependent mobil…

2007

The ac impedance characteristics of a single carrier with space-charge limited current (SCLC) transport in organic layers with field-dependent mobility is analyzed, indicating the similarities as well as the differences to the constant mobility case. The model provides capacitance spectra and transit times from different calculation methods, in relation to the electric field distribution in the SCLC regime. It is found that the low frequency capacitance lies in the range 3Cg/4 < Cif < Cg, with respect to the geometric capacitance Cg. An approximated expression for the variation of the transit time with applied bias is derived, in good agreement with exact calculations. Experimental results …

Shifting of wrapped phase maps in the frequency domain using a rational number

2016

The number of phase wraps in an image can be either reduced, or completely eliminated, by transforming the image into the frequency domain using a Fourier transform, and then shifting the spectrum towards the origin. After this, the spectrum is transformed back to the spatial domain using the inverse Fourier transform and finally the phase is extracted using the arctangent function. However, it is a common concern that the spectrum can be shifted only by an integer number, meaning that the phase wrap reduction is often not optimal. In this paper we propose an algorithm than enables the spectrum to be frequency shifted by a rational number. The principle of the proposed method is confirmed b…