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2014

SURFACE

Articles 1 - 3 of 3

Full-Text Articles in Nanoscience and Nanotechnology

Observation Of Coulomb Repulsion Between Cu Intercalants In Cuxbi2se3, Chris Mann, Damien West, Ireneusz Miotkowski, Yong P. Chen, Shengbai Zhang, Chih-Kang Shih Apr 2014

Observation Of Coulomb Repulsion Between Cu Intercalants In Cuxbi2se3, Chris Mann, Damien West, Ireneusz Miotkowski, Yong P. Chen, Shengbai Zhang, Chih-Kang Shih

Birck and NCN Publications

Using scanning tunneling microscopy and ab initio simulations, we have identified several configurations for Cu dopants in CuxBi2Se3, with Cu intercalants being the most abundant. Through statistical analysis, we show strong short-range repulsive interactions between Cu intercalants. At intermediate range (>5 nm), the pair distribution function shows oscillatory structure along the < 10 (1) over bar > directions, which appear to be influenced by different diffusion barriers along the < 10 (1) over bar > and < 2 (1) over bar(1) over bar > directions.


Integrating Non-Planar Metamaterials With Magnetic Absorbing Materials To Yield Ultra-Broadband Microwave Hybrid Absorbers, Wei Li, Tianlong Wu, Wei Wang, Jianguo Guan, Pengcheng Zhai Jan 2014

Integrating Non-Planar Metamaterials With Magnetic Absorbing Materials To Yield Ultra-Broadband Microwave Hybrid Absorbers, Wei Li, Tianlong Wu, Wei Wang, Jianguo Guan, Pengcheng Zhai

Birck and NCN Publications

Broadening the bandwidth of electromagnetic wave absorbers has greatly challenged material scientists. Here, we propose a two-layer hybrid absorber consisting of a non-planar metamaterial (MM) and a magnetic microwave absorbing material (MAM). The non-planar MM using magnetic MAMs instead of dielectric substrates shows good low frequency absorption and low reflection across a broad spectrum. Benefiting from this and the high frequency strong absorption of the MAM layer, the lightweight hybrid absorber exhibits 90% absorptivity over the whole 2-18 GHz range. Our result reveals a promising and flexible method to greatly extend or control the absorption bandwidth of absorbers. (C) 2014 …


Non-Faradaic Impedance Characterization Of An Evaporating Droplet For Microfluidic And Biosensing Applications, Piyush Dak, Aida Ebrahimi, Muhammad A. Alam Jan 2014

Non-Faradaic Impedance Characterization Of An Evaporating Droplet For Microfluidic And Biosensing Applications, Piyush Dak, Aida Ebrahimi, Muhammad A. Alam

Birck and NCN Publications

We have developed a general numerical/analytical theory of non-faradaic impedance of an evaporating droplet, and validated the model by experiments involving droplets of various analyte concentrations deposited on a surface defined by coplanar electrodes. The impedance of the droplet Z(n(0),t,f) is analyzed as a function of the concentration (n(0)) of the ions in the solution, the measurement frequency (f) and the evaporation time (t). We illustrate the versatility of the model by determining the sensitivity enhancement alpha(t) of the droplet-based impedimetric nano-biosensor under different regimes of operation. The model should have broad applications in the characterization/optimization of droplet-based systems, especially …