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It is well accepted that the use of nanoparticles in microwave absorbents (MA) can enhance their flexibility and performance. In this work, Y-type barium hexaferrite (Al2Y, Mg2Y, and Ni2Y), MnO2, and polyaniline nanoparticles were successfully prepared by using methods of sol–gel auto combustion, chemical co-precipitation and interfacial polymerization, respectively. The prepared nanoparticles were then inserted within a matrix of polyester resin. The phase structure, particle size, morphology, and performance of the prepared absorbers were indicated by an X-ray diffractometer (XRD), a scanning electron microscope (SEM), and a vector network analyzer (VNA), respectively. The influence of four critical parameters on the performance of the absorbers was studied by the Taguchi method to achieve an optimal formulation. For this, parameters investigated include the type of metal in Y-type barium hexaferrite (Al, Mg, and Ni) and the weight ratios of hexaferrite, MnO2, and polyaniline to the total weight of the sample. The results displayed that the sample prepared under optimal conditions has good impedance matching, and minimum reflectance loss (RL) of −36 dB at 10.5 GHz (equal to 99.99% effective absorption) with the thickness of 1.9 mm. Therefore, the optimal nanocomposite based on polyester containing the filler nanoparticles of Al2Y barium hexaferrite/MnO2/polyaniline is an excellent candidate for microwave absorption. [ABSTRACT FROM AUTHOR]

The field emission properties (FE) of a heteroarchitecture comprised of gadolinium hexaboride nanoparticles uniformly decorated over Cu2O nanoneedles (GdB6/Cu2O) have been investigated at the base pressure of ~1 × 10−8 mbar. Under the optimized pulsed laser deposition (PLD), a well-adhered coating of GdB6 nanoparticles on chemically synthesized cuprous oxide (Cu2O) nanoneedles has been obtained. A plausible growth mechanism of the hierarchical assembly of GdB6 nanoparticles on the Cu2O nanoneedles is explained on the basis of structural analysis carried out using SEM and TEM. A low turn-on field of ~2.3 V μm−1 (to draw an emission current density ~1 μA cm−2) is observed along with stable emission current at the preset value of ~2 μA over 4 h. The enhanced emission behaviour of the GdB6/Cu2O heteroarchitecture, in contrast to the pristine Cu2O nanoneedles, is attributed to its high aspect ratio and low work function. The observed FE results demonstrate GdB6/Cu2O heteroarchitecture as a potential candidate for application in various vacuum nano/microelectronic devices. [ABSTRACT FROM AUTHOR]

A Bi2O3 nanoparticle modified BiOCl composite was synthesized by a solvothermal method combined with in situ reduction and oxidation in KBH4 and H2O2 solutions respectively. The thickness of a BiOCl nanosheet and the amount of Bi2O3 nanoparticle can be adjusted by changing the KBH4 concentration. The structure, morphology, elemental composition and optical absorption performance were characterized by using an X-ray diffraction diffractometer, a scanning electron microscope, a high resolution transmission electron microscope, an X-ray photoelectron spectroscope and a UV-Vis diffuse reflection spectroscope respectively. A nanolayered hierarchical structure of BiOCl was observed, and Bi2O3 nanoparticles were found to be evenly distributed on the surface/interface of the nanosheets. The photocatalytic activity of the composite was tested by the degradation of 40 mg L−1 methyl orange solution under UV light illumination. The Bi2O3/BiOCl composite prepared in a KBH4 concentration of 0.02 M achieved the highest photocatalytic rate of 95.7% in 8 min under UV light illumination with a kinetic constant of 0.3125 l min−1. The photocatalytic mechanism of the composite has been discussed. [ABSTRACT FROM AUTHOR]

A one-pot multi-component, green, and highly efficient protocol has been described for the synthesis of a wide range of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones using TAPC supported on boehmite nanoparticles (BNPs-TAPC) as an eco-friendly and recyclable nanocatalyst in excellent yields under solvent-free conditions. A short reaction time, easy and quick isolation of the products, use of inexpensive heterogeneous nanocatalysts, a solvent-free process and excellent chemoselectivity are other remarkable features of this environmentally benign protocol. BNPs-TAPC was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and FT-IR methods. [ABSTRACT FROM AUTHOR]

A microfluidic dielectrophoresis platform consisting of curved microelectrodes was developed and integrated with a Raman spectroscopy system. The electrodes were patterned on a quartz substrate, which has insignificant Raman response, and integrated with a microfluidic channel that was imprinted in poly-dimethylsiloxane (PDMS). We will show that this novel integrated system can be efficiently used for the determination of suspended particle types and the direct mapping of their spatial concentrations. We will also illustrate the system's unique advantages over conventional optical systems. Nanoparticles of tungsten trioxide (WO3) and polystyrene were used in the investigations, as they are Raman active and can be homogeneously suspended in water. [ABSTRACT FROM AUTHOR]

A facile method for the functionalization of multiwall carbon nanotubes (MWCNT) by photopolymerization of 5-mercapto-2,2′-bithiophene modified metal (Au or Ag) nanoparticles on the surface of the MWCNT is developed. [ABSTRACT FROM AUTHOR]