Sharif Digital Repository

Titanium oxide (TiO2)-based photodetectors were fabricated using a thermal oxidation technique. The effect of two different annealing temperatures on morphology, structure, and I-V characteristics has been investigated. TiO2/Si heterostructure exhibited diode-like rectifying I-V behavior both in dark and under illumination. Dependence in photoresponse on annealing temperature was observed that was related to effective surface area of quasi-one-dimensional TiO2 nanostructures. Fabricated TiO2/Si diodes in 850 °C as the lower annealing temperature showed higher responsivity and sensitivity compared with grown ones in 950 °C (R850 °C/R950 °C ∼ 5 and S850 °C/S950 °C ∼ 1.6). Rather good... 

In this study, we present fabrication and characterization of a gas ionization sensor based on high aspect ratio one-dimensional CuO nanowires as the field enhancing medium. Self-organized arrays of CuO nanowires have been synthesized based on a low-cost thermal oxidation method and integrated into a gas ionization sensor (GIS). The self-organized arrays of CuO nanowires have been employed to detect the identity of several gas species such as He, Ar and CO at ambient temperature and pressure. The sharp nanoscale size of CuO tips provide very high electric fields at moderate voltages (less than 100 V) and provoke the breakdown of different gases. The reduced breakdown current of the metal... 

Thermally oxidized nanodiamond (OND), amine-functionalized ND (AND) and untreated ND (UND) were added to epoxy/TETA at 1 wt % loading. The ND enhanced the dynamic storage modulus of epoxy while decreasing the glass transition temperature because of the increment of free volume in the vicinity of the ND surfaces. The ND induced an acceleration effect on the curing reaction which could be due to functional groups of the ND and lack of any steric hindrance on molecules by the ND particles themselves. The Vyazovkin model-free isoconversional method indicated that all NDs decreased the activation energy; among them, AND showed the lowest value because of the significant promotion of the epoxide... 

Development of a model for optimal power generation from the thermal oxidation of a low concentration coal bed mine has been considered as the main objective of this investigation. The model has been applied to identify the optimal thermodynamic characteristics of the power generation system through using a mixture with 1.6% methane concentration in a recuperative lean-burn gas turbine and coupling a gas engine to the system for more power generation from the remaining coal bed methane. The implementation of the model based on the real site condition would lead to the generation of 6.97 MW electricity in Tabas coal mine of Iran. © 2016 Taylor & Francis  

Surface chemistry of as-received nanodiamond (ND) was first tailored by dry thermal oxidation to obtain carboxylated ND (ND-COOH) and by wet chemistry to obtain ethylenediamine-functionalized ND (ND-EDA). Then, the surface-functionalized ND particles were dispersed in polyamide 6 (PA6) using the melt-mixing method. Transmission optical and scanning electron microscopies indicated a fine dispersion at low nanodiamond concentrations, e.g. 0.25 wt%, particularly with ND-EDA. Differential scanning calorimetry revealed that ND-EDA favoured the α-phase crystal and enhanced the degree of crystallinity of PA6. Experimental data indicated that ND-EDA had considerably improved tensile properties at... 

Nanowire arrays of copper oxide were first grown vertically using simple and cost effective thermal oxidation method on a copper foil. Subsequently, in order to deposit and grow PbS nanocyrstalline thin films on CuO NWs by utilizing the chemical bath deposition technique, these arrays were immersed as the substrate in the reaction solution consisting of Pb(NO3)2, (NH2)2CS and NaOH. The final products were characterized in detail by which the formation of uniform, unique arrays of CuO@PbS core–shell NWs was confirmed. Due to the nature of methods employed in synthesis of this hetero structure, the tuning of core and shell size and consequently properties of the novel structure is easily... 

The bioinertness makes surface treatments essential to improve the bioactivity of porous titanium scaffold, and surface treatment might affect their mechanical properties. So finding an optimum condition lying between bioactivity and mechanical properties seems to be curial. In this research, the effect of the time of the thermal oxidation at 600 °C on apatite formation and mechanical properties of the porous titanium scaffold was studied. The results of thin film X-ray diffraction and Raman spectroscopy indicated that the surface of heat treated samples up to 480 min was mainly covered by rutile. Also, wettability measurement and in vitro apatite formation ability assessment indicated that... 

In the present work, a series of nanohybrids based on UiO-66 as a physicochemical stable metal-organic framework (MOF) and different amounts of thermally oxidized nanodiamond (OND) (0.5–10 wt%) were synthesized and used as adsorbents for anionic (methyl red, MR, and methyl orange, MO) and cationic (malachite green, MG, and methylene blue, MB) dyes from contaminated water in single and binary dye solutions. The single adsorbents and their nanohybrids were characterized by FESEM, FTIR, XRD,TGA, BET, and zeta potential measurements. The experimental adsorption results displayed that the synthesized nanohybrids presented higher adsorption capacity for anionic dyes compared to cationic dyes in... 

In this study, nano-sized diamond particles (ND) were functionalized in two consecutive stages. First, dry thermal oxidation was employed to obtain carboxylated ND. In the next step, carboxylated ND was properly surface modified through wet chemistry to acquire aminated-ND (ND-NH2). Then, polyaniline (PANI) was synthesized in the presence of aminated-ND particles at a broad concentration from 1 wt% to 70 wt% to obtain PANI/ND hybrid nanostructures. The chemical structure, morphology, and thermal stability of nanoparticles were comprehensively characterized by different techniques such as FT-IR, UV–visible, TGA, XRD, FESEM, and TEM. It was observed that the morphology of PANI/ND... 

This article deals with the adsorption performances of the unmodified nanodiamond (ND) and thermally oxidized nanodiamond (Ox-ND) for the removal of different heavy metal ions such as Fe (III), Cu (II), Cr (VI), and Cd (II) from wastewater. The adsorption capacities of the ions onto adsorbents are higher and follow the order: Ox-ND-3 > Ox-ND-1.5 > ND, which is consistent with their surface areas, zeta potentials, and the presence of carboxyl groups, suggesting that electrostatic attractions between the positive metal ions and the negatively charged adsorbents are the predominant adsorption mechanisms. Adsorption capacities of these adsorbents were found to be 26.8, 31.3, and 45.7 mg/g for Fe... 

ZnO tetrapods and rods were grown on silicon and thermally oxidized porous silicon substrates with and without Au catalyst layer by carbothermal reduction of ZnO powder through chemical vapor transport and condensation method (CVTC). Porous silicon was fabricated by electrochemical etching of silicon in HF solution. The effect of substrates on morphology, structure and photoluminescence spectra of ZnO nanostructures has been studied. The texture coefficient (TC) of each sample was calculated from XRD data that demonstrated random orientation of ZnO nanostructures on the oxidized porous silicon substrate. Moreover, TC indicates the effect of Au catalyst layer on formation of more highly... 

Hydrogen storage capacities of raw, oxidized, purified and Fe-doped multi-walled carbon nanotubes (MWCNTs) were studied by electrochemical method. Based on transmission electron microscopy and Raman spectroscopic data, thermal oxidation removed defective graphite shells at the outer walls of MWCNTs. The analysis results indicated that the acid treatment dissolved most of the catalysts and opened some tips of the MWCNTs. Thermal gravimetric analysis and differential scanning calorimetry results illustrated that by oxidation and purification of MWCNTs, the weight loss peak shifts toward a higher temperature. N2 adsorption isotherms of the purified and oxidized MWCNTs showed an increase in N2...