Dielectric Resonator Method for Measuring the Electrical Conductivity of Carbon Nanotubes from Microwave to Millimeter Frequencies

We describe a dielectric resonator-based measurement method for determining the electrical conductivity of carbon nanotubes at microwave to millimeter frequencies. This measurement method is not limited by the metal conductor contact resistances or impedance mismatch commonly encountered in the measurement of single nanotubes. The measurement of carbon nanotubes yielded conductivities of approximately 0.08×107 S/m

Full-wave analysis of dielectric-loaded cylindrical waveguides and cavities using a new four-port ring network

“© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”In this paper, a full-wave method for the electromagnetic analysis of dielectric-loaded cylindrical and coaxial waveguides and cavities is developed. For this purpose, a new four-port ring network is proposed, and the mode-matching method is applied to calculate the generalized admittance matrix of this new structure. A number of analyses on dielectric-loaded waveguide structures and cavities have been conducted in order to validate and to assess the accuracy of the new approach. The results have been compared with theoretical values, numerical modeling from the literature, and data from commercial electromagnetic simulators. The method has been also applied to the accurate determination of dielectric properties, and we provide an example of these measurements as another way to validate this new method. © 1963-2012 IEEE.This work was supported by the Ministry of Science and Innovation of Spain under Project MONIDIEL (TEC2008-04109). The work of F. L. Penarada-Foix was supported by the Conselleria de Educacion of the Generalitat Valenciana for economic support (BEST/2010/210).Penaranda-Foix, FL.; Janezic, MD.; Catalá Civera, JM.; Canós Marín, AJ. (2012). Full-wave analysis of dielectric-loaded cylindrical waveguides and cavities using a new four-port ring network. IEEE Transactions on Microwave Theory and Techniques. 60(9):2730-2740. https://doi.org/10.1109/TMTT.2012.2206048S2730274060

Characterizing temporary hydrological regimes at a European scale

Monthly duration curves have been constructed from climate data across Europe to help address the relative frequency of ecologically critical low flow stages in temporary rivers, when flow persists only in disconnected pools in the river bed. The hydrological model is 5 based on a partitioning of precipitation to estimate water available for evapotranspiration and plant growth and for residual runoff. The duration curve for monthly flows has then been analysed to give an estimate of bankfull flow based on recurrence interval. The corresponding frequency for pools is then based on the ratio of bank full discharge to pool flow, arguing from observed ratios of cross-sectional areas at flood 10 and low flows to estimate pool flow as 0.1% of bankfull flow, and so estimate the frequency of the pool conditions that constrain survival of river-dwelling arthropods and fish. The methodology has been applied across Europe at 15 km resolution, and can equally be applied under future climatic scenarios

Dielectric Resonator Method for Measuring the Electrical Conductivity of Carbon Nanotubes from Microwave to Millimeter Frequencies

We describe a dielectric resonator-based measurement method for determining the electrical conductivity of carbon nanotubes at microwave to millimeter frequencies. This measurement method is not limited by the metal conductor contact resistances or impedance mismatch commonly encountered in the measurement of single nanotubes. The measurement of carbon nanotubes yielded conductivities of approximately 0.08 × 10 7 S/m