نتایج جستجو برای: negative dielectric
تعداد نتایج: 572972 فیلتر نتایج به سال:
Metamaterials--or artificial electromagnetic materials--can create media with properties unattainable in nature, but mitigating dissipation is a key challenge for their further development. Here, we demonstrate a low-loss metamaterial by exploiting dark bound states in dielectric inclusions coupled to the external waves by small nonresonant metallic antennas. We experimentally demonstrate a dis...
Negative phase advance through a single layer of near-IR negative index metamaterial (NIM) is identified through interferometric measurements. The NIM unit cell, sub-wavelength in both the lateral and light propagation directions, is comprised of a pair of Au strips separated by two dielectric and one Au film. Numerical simulations show that the negative phase advance through the single-layer s...
We perform a quantitative analysis of the trap density of states (trap DOS) in PbS quantum dot field-effect transistors (QD-FETs), which utilize several polymer gate insulators with a wide range of dielectric constants. With increasing gate dielectric constant, we observe increasing trap DOS close to the lowest unoccupied molecular orbital (LUMO) of the QDs. In addition, this increase is also c...
Experimental results of dielectric investigations for binary mixtures of 2, 3-butanediol, 2, 3-BD, in2-ethyl-1-hexanol, 2EH, were reported for various mole fractions and temperatures (298.2-308.2) Kand they were used to calculate dielectric parameters such as Kirkwood correlation factor, excesspermittivity and Bruggeman parameter. These parameters were used to carry out temperaturedependent die...
Traveling Wave Tubes (TWTs) consist of different elements. The most important element of TWT is the RF circuit. RF circuits in helix TWTs need a dielectric support to hold the helix; this support also has an effect in electromagnetic properties of RF circuits. A novel dielectric support is proposed to reduce the second harmonic of helix TWTs. The dielectric support in this structure consists of...
The subject of enhancing microstrip patch antennas directivity, using either a frequency selective surface (FSS) or a double-negative (DNG) metamaterial slab, has been investigated by a number of researchers in recent years. The purpose of this paper is to show that we can also achieve the same goal by using a much simpler design for the superstrate, namely a dielectric slab, whose performance ...
the purpose of the present study was to investigate the relationship between fear of negative evaluation (fne) and communication strategies (css) among iranian efl learners. it was aimed to examine the differences in the use of communication strategies between speakers with high or low degree of fear of negative evaluation. the current study was a case study consisting of 10 english learners at...
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