A perfect ultra-narrow band infrared metamaterial absorber based on the all-metal-grating structure is proposed. The absorber presents a perfect absorption efficiency of over 98% with an ultra-narrow bandwidth of 0.66 nm at normal incidence. This high efficient absorption is contributed to the surface plasmon resonance. Moreover, the surface plasmon resonance-induced strong surface electric fie...

We report on a survey for narrow (FWHM < 600 km s) C iv absorption lines in a sample of bright quasars at redshifts 1.8 6 z < 2.25 in the Sloan Digital Sky Survey. Our main goal is to understand the relationship of narrow C iv absorbers to quasar outflows and, more generally, to quasar environments. We determine velocity zeropoints using the broad Mg ii emission line, and then measure the absor...

The detection of inflows at the scale dusty torus and smaller is crucial for investigating process supermassive black hole (SMBH) accretion. However, only a few cases inflowing gas small scales have been reported through redshifted broad absorption lines so far. Here we report nine narrow (NALs) Mg + ions with speeds 1071–1979 km s −1 , which are likely along directions close to axes accretion ...

We analyse high-resolution VLT+UVES spectra of the low-ionization intrinsic absorber observed in the BAL QSO SDSS J001130.56+005550.7. Two narrow absorption systems at velocities −600 km s−1 and −22000 km s−1 are detected. The low-velocity system is part of the broad absorption line (BAL), while the high-velocity one is well detached. While most narrow absorption components are only detected in...

Cavity ring-down spectroscopy (CRDS) is an extremely sensitive absorption technique that has been applied primarily to gas samples, which are characterized by having narrow absorption features. Recently, CRDS has also been applied to liquid samples, which have broad absorption features. The use of small inexpensive diode lasers as light sources for liquid samples is demonstrated. The low cost c...

[1] The influence of narrow optical resonances, which result from trapping of light rays via total internal reflection in water droplets, on the absorption of shortwave (SW) solar radiation has been estimated through high resolution Mie scattering calculations. Our results indicate that these resonances engender an increase in absorption of solar radiation by cloud droplets that is several W/m ...

in this research fe-tio2 nanocomposites with different molar ratios of fe/ti were prepared as nano-photocatalyst using a modified sol-gel process at ambient temperature. crystallographic properties of nanocomposites were characterized by x-ray diffraction (xrd). surface morphology and mean particle size of nanocomposites were specified by field emission scanning electron microscopy (fesem) and ...

Auxetic lattices have attracted increasing attention due to their unusual mechanical behavior and potential for an array of applications. However, a narrow window stiffness realizable given cell topology limits In this study, pair novel 2D re-entrant auxetic capable exhibiting enhanced energy absorption is proposed by introducing vertical ligaments into conventional structures. These modified w...