다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted.

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A review on the visible light active titanium dioxide photocatalysts for environmental applications

X-ray analysis of ZnO nanoparticles by Williamson–Hall and size–strain plot methods

X-ray diffraction analysis by Williamson-Hall, Halder-Wagner and size-strain plot methods of CdSe nanoparticles- a comparative study

A facile Au nanoplates and reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) was fabricated via a simple electrochemical method, denoted as Au/RGO/GCE. The Au/RGO/GCE electrode was used for the simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The modified electrodes fabricated by different methods presented different morphologies and performances for determination of AA, DA, and UA. Three well-defined voltammetric peaks along with remarkable increasing electrooxidation currents were obtained on the Au/RGO/GCE with needle-like Au nanoplates in differential pulse voltammetry (DPV) measurements. It was found that there are linear relationships between the peak currents and the concentrations in the range of 2.4 × 10 −4 to 1.5 × 10 −3  M (AA), 6.8 × 10 −6 to 4.1 × 10 −5  M (DA), and 8.8 × 10 −6 to 5.3 × 10 −5  M (UA), and the limits of simultaneous determination (based on S/N  =  3) are 5.1 × 10 −5  M, 1.4 × 10 −6  M, and 1.8 × 10 −6  M for AA, DA and UA, respectively. Additionally, the Au/RGO/GCE electrode presented well anti-interference ability, stability and reproducibility.

A facile electrochemical sensor based on reduced graphene oxide and Au nanoplates modified glassy carbon electrode for simultaneous detection of ascorbic acid, dopamine and uric acid

https://profdoc.um.ac.ir/articles/a/1019188.pdf

Effects of annealing temperature on some structural and optical properties of ZnO nanoparticles prepared by a modified sol–gel combustion method

Synthesis, magnetic properties and X-ray analysis of Zn0.97X0.03O nanoparticles (X = Mn, Ni, and Co) using Scherrer and size-strain plot methods

ZnO nanorods were synthesized at low temperature by hydrothermally heating 0·1 M solution of ZnCl2 for 5, 10 and 15 h at a pH of 10. No template, seeded substrate, catalyst and autoclave were employed for the synthesis of ZnO nanorods. The effect of heating durations on the morphology and crystal orientation of the structure were investigated by using scanning electron microscopy and X-ray diffraction, respectively. SEM images showed that the flower-like structures were formed in 5 h hydrothermally-heated sample, whereas the hexagonal zinc oxide nanorods were perfectly fabricated with the increase in growth time. XRD patterns showed that the preferred orientation in nanorods could be controlled by hydrothermal treatment time. The crystallite size and microstrain were analysed by Williamson–Hall and Halder–Wagner methods. These results revealed the presence of defects in ZnO nanorods. However, by increasing the hydrothermal treatment time, both defects in lattice and crystallite size are decreased.

/pdf/facile-template-free-hydrothermal-synthesis-and-microstrain-4406bz90te.pdf

Facile template-free hydrothermal synthesis and microstrain measurement of ZnO nanorods

In this study, pure and NH2-functionalized graphene oxide (GO) nanosheets have been added to the cement mortar with different weight percents (0.05, 0.10, 0.15, 0.20 and 0.25 wt%). In addition, the effects of functionalizing GO on the microstructure and mechanical properties (flexural/compressive strengths) of cement composite have been investigated for the first time. Scanning electron microscopy (SEM) images showed that GO filled the pores and well dispersed in concrete matrix, whereas exceeding GO additive from 0.10 wt% caused the formation of agglomerates and microcracks. In addition, mercury intrusion porosimetry confirmed the significant effects of GO and functionalizing groups on filling the pores. NH2-functionalizing helped to improve the cohesion between GO nanosheets and cement composite. Compressive strengths increased from 39 MPa for the sample without GO to 54.23 MPa for the cement composites containing 0.10 wt% of NH2-functionalized GO. Moreover, the flexural strength increased to 23.4 and 38.4% by compositing the cement paste with 0.10 wt% of pure and NH2-functionalized GO, compared to the sample without GO, respectively. It was shown that functionalizing considerably enhanced the mechanical properties of GO/cement composite due to the interfacial strength between calcium silicate hydrates (C-S-H) gel and functionalized GO nanosheets as observed in SEM images. The morphological results were in good agreement with the trend obtained in mechanical properties of GO/cement composites.

/pdf/reinforcing-graphene-oxide-cement-composite-with-nh2-1v99h6g1d5.pdf

Reinforcing graphene oxide/cement composite with NH2 functionalizing group

Zn1-xMnxO (x = 0, 0.02, 0.06, 0.10, 0.15) nanopowders were synthesized by the sol–gel technique calcinated at low temperatures. By decreasing the grain size in ZnO, the solubility of magnetic impurity has been increased and no detectable secondary phases were observed even in the high Mn-doping samples. The phase formation, size and morphology of nanoparticles were investigated using X-ray diffraction and SEM observations. The samples were ferromagnetic and the Curie point was found in the range 150–170 K for Zn0.94Mn0.06O and 135–150 K for Zn0.98Mn0.02O. Optical characterization and the effect of doping were carried out by means of Fourier transform infrared (FTIR) spectroscopy. Kramers–Kronig analysis was employed to evaluate the optical constants of pure ZnO and ZnO:Mn nanopowders.

/pdf/synthesis-and-structure-of-pure-and-mn-doped-zinc-oxide-3cn2n24lab.pdf

M. Ebrahimizadeh Abrishami

Papers

Effects of annealing temperature on some structural and optical properties of ZnO nanoparticles prepared by a modified sol–gel combustion method

Synthesis, magnetic properties and X-ray analysis of Zn0.97X0.03O nanoparticles (X = Mn, Ni, and Co) using Scherrer and size-strain plot methods

Facile template-free hydrothermal synthesis and microstrain measurement of ZnO nanorods

Reinforcing graphene oxide/cement composite with NH2 functionalizing group

SYNTHESIS AND STRUCTURE OF PURE AND Mn-DOPED ZINC OXIDE NANOPOWDERS