Advanced Materials Research Vol. 486

Abstract: In order to reach soft x-ray wavelength starting from the UV seed laser, we used the recently Echo-Enabled Harmonic Generation (EEHG) scheme proposed by D. Xiang. This scheme uses two laser modulators in combination with two dispersion sections to generate higher harmonic radiation as compared with the normal limit arising from energy spread for HGHG. Using representative, realistic and optimized parameters, finally, we get the beam density modulation at the 88th harmonic of the seed laser. The performance of the above event is estimated by means of GENESIS.

Abstract: An analysis for the effect of nanoparticles in lubricants on load capacity is performed to study a rectangular thrust pad hydrostatic bearing with a central recess. The closed-form solution of the bearing load is derived analytically and presented for nanofluids with interparticle interaction. Results reveal that in the presence of nanoparticles, the enhanced viscosity could result in an increase in bearing load; moreover, this increase dramatically increases as particle volume fraction and/or interparticle interaction increases. The effect of nanoparticles on the bearing load can be magnified by decreasing the bearing gap.

Abstract: Degradation of dye wastewater was studied by using nanoferrous modified bentonite as the heterogeneous catalyst for a Fenton-like oxidation. By comparing the effect of homogeneous Fenton reactions as well as heterogeneous Fenton-like process for nanomodified bentonite, it is found that the advanced oxidation processes assisted by nanoferrous/bentonite complexes exhibit the stronger degradation capacity. And the removal rate of Fenton-like reaction increased from 23.6% to 75.5% when the ferrous concentration increasing from 20 to 100mmol/L. Being compared with homogeneous Fenton reactions, 20% increased degradation efficiencies is obtained by Fenton-like oxidation process for nanomodified bentonite under 6g nanoferrous/bentonite complexes in 100mL dye wastewater.

Abstract: Cobalt and its alloy have been identified as potential candidates for replacing hexavalent Chromium plating in corrosion resistant coating in acidic environment. In this study, the effect of alloys addition towards elemental composition, crystallographic structure characterization, surface morphology, hardness and potentiodynamic polarization of the cobalt alloys coatings is reported. Addition of Nickel (Ni) and Iron (Fe) to the Cobalt (Co) coatings are deposited on stainless steel substrate by electrodeposition method. The deposition is performed at acidic environment of pH 3. The granule sizes of cobalt alloys prepared by electrodepositionmethod are in the range of 34.95 nm72.08 nm. The microhardness of CoNiFe is the highest (267.8 HV) compared to Co and CoFe. CoNiFeperforms the smallest corrosion rate with 1.322 mmpy. It is found thatthe addition of Ni and Fe into pure cobaltimproves the hardness and corrosion behavior.

Abstract: In this paper, novel active narrowband notch filters with triple-layer composite nanostructures on a GaN-based LED are obtained by mainly adjusting the grating period and duty cycle. The three layers consist of two dielectric thin layers and one metallic / dielectric grating layer. The grating layer composes of subwavelength period and thickness rectangular stripes, which lies between a transition layer and a protecting layer. Line-width and attenuation peak properties of the resonance filters are calculated and investigated by using a full vector implementation of Rigorous Coupled Wave Analysis (RCWA) algorithm. It is shown that the grating period can significantly change the filter peak wavelength, and the grating duty cycle heavily changes the filter line-width. The filter attenuation peak has a red shift with 23.3nm as the grating period increases 18nm. The FWHM (Full Width at Half Maximum) of the filter reduces from 1.9nm to 0.28nm as the duty cycle changes from 0.55 to 0.3, which compressed more than six times. Moreover, thickness of each composite nanostructure layer can also affect the narrowband width and peak wavelength of the filter. The results provide guidance in designing, optimizing and fabricating such an active narrowband filter with highly integrated photonic devices.

Abstract: Poly (Vinyl Alcohol)(PVA)/In-Sn hydroxide (ITH) nanofibers were prepared via electrospinning, then followed by calcining at 400 , 475 , and 550 to obtain indium tin oxide (ITO) nanofibers. The influencing factors of solution properties, viscosity and electrical conductivity on the formation and morphology of electrospun fibers was investigated. The microstructure of PVA/ITH and ITO nanocomposites were characterized by scanning electron microscopy (SEM). And the crystalline structure of ITO nanocomposites was analyzed by X-ray diffractometry (XRD). The results showed that the average diameter and variation coefficient of obtained PVA/ITH nanofibers decreased after the adding of ITH. The ITO nanofibers became thinner and more uneven with the increasing of calcined temperature. XRD patterns proved that ITO nanoparticles existed after calcined and showed the structure was strongly depended on the calcined temperature. The bixbyite and the corundum type could be fabricated according the calcined temperature.

Abstract: The FeVO₄ nanoparticles were synthesized by a precipitation process. The FeVO₄ nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis diffuse reflectance spectroscopy (DRS). It was found that the prepared FeVO₄ nanoparticles show an average grain size of 50-80 nm in diameter, and strong visible-light absorption with absorption onset of 515 nm, indicating a narrow optical band gap of 2.4 eV. Consequently, the FeVO₄ nanoparticles show high visible-light photocatalytic activity for decomposition of methyl orange.

Abstract: Nanoparticles of CoCrFeO₄ ferrite in the particle size range of 9 - 38 nm have been prepared by a sol-gel auto combustion method. Synthesized powders were annealed at four different temperatures viz. 400 °C, 600 °C, 800 °C and 1000 °C. Particle sizes are determined by X-ray analysis and TEM. The size of the nanoparticles increase linearly with sintering temperature and time, most probably due to coalescence that increases as sintering temperature increases. The saturation magnetization increases from 62 to 81 emu/g and coercivity initially increases up to 814 Oe and then decreases to 366 Oe with increase in particle size and sintering temperature. The typical blocking temperature increases from 135 to 165 K with increasing particle size.

Abstract: An experimental study has been conducted in premixed and counterflow diffusion flames in order to obtain the nanocarbon materials. In this paper the synthesis of fullerenes, carbon nanotubes and superhydrophobic soot surface in the regime of hydrocarbon flames were studied. The original results in the field of synthesis of fullerenes, carbon nanotubes and syperhydrophobic soot in hydrocarbon flames were carried out for the last years at the Institute of Combustion Problems.

Abstract: The present work is devoted to studying photoelectrical properties of the solar cells covered with nickel oxide nanoparticles synthesized in counter flow propane flame. In the given case, the nanoparticles of oxides play the role of quantum points on the surface of the solar cells and promotes effective absorption of light energy. The applying of silicon solar cells of nickel oxide nanoparticles to the surface caused the increase of output open circuit voltage of 4-7 %, the increase of short - circuit current of 20 - 28 %, that in total caused the increase of efficiency of the solar cells by 2-3%.