Effects of the Molecular Weight of PCz on Selective Extraction of Large-Diameter Semiconducting Single-Walled Carbon Nanotubes

Due to the difficulty in the selective synthesis of semiconductor (s-) and metal (m-) single-walled carbon nanotubes (SWCNTs), we still need to explore the selective extraction technology of s-SWCNTs. Using Poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl] (PCz) extraction of s-SWCNTs has attracted extensive attention in recent years, because it can selective extraction of large-diameter s-SWCNTs with high purity. However, influence of the molecular weight of this polymer on the s-SWCNTs selective extraction properties remains unclear. In this study, we used PCz with different average molecular weights to study the ability of selective extraction s-SWCNTs from pristine arc discharge carbon nanotubes. Spectra studies indicate that compared to the PCz with lower molecular weight, the PCz with higher molecular weight has better selective extraction ability, and can help to obtain s-SWCNTs with higher purity (>99%) and high yield. FETs devices have been prepared by s-SWCNTs obtained via PCz with higher molecular weight exhibit higher on/off ratio, lower off current and lower subthreshold swing. This work offers a reference of the design and synthesis of PCz polymer that performs sufficient selective ability in extracting s-SWCNTs with promising applications.

Effect of Single Walled Carbon Nanotubes on the Series Resistance and Trap Energy of Malachite Green Dye Based Organic Device

In this paper, we have estimated the series resistance (Rs) and the trap energy (Ec) of the sandwiched type Malachite Green (MG) dye-based organic device and have also observed the influence of single-walled carbon nanotubes (SWCNT) on both of these parameters. To form the organic device, we have used Indium Tin Oxide (ITO) coated glass as the front electrode and Aluminium (Al) as a back electrode by using the spin coating technique. The values of series resistance are measured from both I-V characteristics and by utilizing Cheung Function due to the non ideal behavior of organic devices. We have also extracted the values of Rs by using H (I) versus I plot and verified the values with the measured values of Rs from the Cheung function. The extracted values of series resistance using these three processes remain consistent with each other in showing that the values of series resistance have been reduced considerably in the presence of SWCNT. The trap energy has been estimated from the steady-state current-voltage characteristics. There is a significant correlation in between series resistance and the trap energy of the organic device. The presence of Single-Walled Carbon Nanotubes reduces the trap energy from 0.086 eV to 0.057 eV. Lowering of the trap energy of the metal-organic layer interface in presence of Single Walled Carbon Nanotubes attributes to the reduction of the value of the series resistance. The extracted value of Rs decreases from 0.154 MΩ to 0.0389 MΩ in presence of SWCNT. Decrease in the value of both of these parameters in the presence of SWCNT will definitely improve the charge transport mechanism of the organic device and thereby the conductivity.

Stability, Structural and Electronic Properties of Indium Phosphide Wurtzite-Diamantane Molecules and Nanocrystals: A Density Functional Theory Study

The density functional theory is applied for examining the electronic structure and spectroscopic properties for InP wurtzite molecules and nanocrystals. In this paper we present calculations of the energy gap, bond lengths, IR and Raman spectrum, reduced mass and force constant. The results of the presented work showing that the InP’s energy gap was fluctuated about to experimental bulk energy gap (1.49 eV). Results of spectroscopic properties including IR and Raman spectrum, reduced mass and force constant as a function of frequency were in accordance with the provided experimental results. In addition, the study of the Gibbs free energy proved the stability phase of InP wurtzoids against transition to InP diamondoids structure.

Study on the Tribological Mechanism of Ultrafine SiO2/MoS2 Powders in Complex Calcium Sulfonate Grease

The purpose of this work was to study and further clarify the anti-wear and anti-friction mechanism of ultrafine SiO2/MoS2 powders in the complex calcium sulfonate grease. In this paper, 15nm nanoSiO2, 1μm MoS2 and commercial NLGI Grade No.2 complex calcium sulfonate grease were used as the research objects, SEM, EDS and XPS were used to study the morphology, composition and film chemical constitution of the long friction wear spots of grease containing single nanoSiO2 powder, ultrafine MoS2 powder and the two compound powders, which formed in the process of four ball long friction. The results show that nanoSiO the grease plays a role in filling the undercut, ball bearings and polishing and forming high hardness Ca3Fe2(SiO4)3 and part of Fe2O3 anti-wear films in the process of long friction. The ultrafine MoS2 powder has a self-repairing effect to fill the grooves,forming the MoS2, MoO3 anti-friction films and Fe2(SO4)3 anti-wear film. The two powders in the composite grease have a synergistic effect, acting on the friction pair together, and simultaneously forming self-repairing anti-friction and anti-wear films, thereby further improving the tribological performance of the base grease.

The Role of Particles and Clusters Size on the Catalytic Activity of Different Types of Gold Nanocatalysts for Benzyl Alcohol Oxidation

: In this paper, activation procedures under size effects of some gold nanoparticles (Au101, Aunaked and Aucitrate) and nanoclusters (Au8 and Au9) immobilized on powder Norit® activated carbon (abbreviated to AC) and/or Vulcan carbon (abbreviated to VC) on the catalytic activity of gold nanocatalysts were studied. The gold nanostructures were activated through the washing procedure with a base in MilliQ water or hot toluene and then followed by heating in static air (abbreviated to W+S) or under vacuum (abbreviated to W+V) at 100 °C for 3 h. The highest activity of gold nanocatalysts for benzyl alcohol oxidation was obtained for activated (W+V) ‘naked’ gold nanoparticles immobilized on Norit® activated carbon when the gold nanoparticle diameters was ~4.4 nm.

Water Disinfection Using Silver and Zinc Oxide Nanoparticles

Waterborne disease has changed a basic challenge in human population. recently, the use of nanotechnology and application of nanomaterials for the control of pathogens in water is widely increased in research. Common indicator for microbial quality of water are determine presence of total and fecal coliforms. The purpose of this study was to evaluate the effect of Silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) and combination of them in removing total and fecal coliform bacteria from contaminated water. In this experimental study a synthetic solution was made by adding effluent to distilled water. In each run, the nano silver (20-100 μg /L) and ZnO NPs (0.25-2 mg/L) were added to contaminated water. The samples were tested by 15-tube series method based on the instruction 9221-B of 21th edition of standard method book on water and wastewater experiments. Bacteria removal efficiency were examined in contact times (15, 30,60, 90 and 120) minutes. Our data indicate a decrease in the number of bacteria (MPN) in the presence of the nanoparticles. Results revealed that the removal percentage of coliform bacteria removal increased with increasing the contact time and concentrations of nanoparticles. Ag NPs at a concentration of 100 μg /L and ZnO NPs at a concentration of 2 mg/L showed the highest percentage of removal bacteria and the combination of ZnO and Ag NPs have been high synergistic behavior against coliform bacteria in contaminated water. therefore, using a combination of ZnO and Ag NPs can become a new and efficient method for the removal of indicator bacteria from contaminated water.

Study of the Structure, Microstructure and Temperature Dependent Thermal Conductivity Properties of SrTiO3: Via Y3+ Substitution

Yttrium (Y) modified strontium titanate (SrTiO3) powders with initial concentration of Y in the range of 0 to 15 mol% were produced through sol-gel technique. X-ray diffraction (XRD) studies show that all the prepared compounds have a perovskite cubic structure with the space group (Pm3m). The lattice constant, lattice strain and crystallite size of the as-prepared samples were estimated from the XRD pattern which reveals the incorporation of Y into SrTiO3 system, moreover to investigate the quality of the prepared SrYT ceramics powder, the scanning electron microscopy (SEM) was used to determined investigate the morphology, grain size and its distribution. The analysis of the thermal conductivity measurements performed on the obtained powders revealed the effect of the combination of temperature and Y content on the thermal conductivity value, Indeed, the minimum thermal conductivity was 4.12 W/(mK) obtained with 15%Y at 464 K.

Nonlinear Behavior of Single Walled Carbon Nanotube Reinforced Aluminium Alloy Beam

This paper aims to analyze the nonlinear vibration of clamped-clamped buckled beams made of Aluminium alloy (Al-alloy) reinforced with uniformly dispersed Single Walled Carbon Nanotube (SWNT). The mean field homogenization technique is used to predict the effective material properties of the beams. The equation of motion governing the nonlinear behavior is solved using an exact method. The effects of various parameters including axial load, vibration amplitude, SWNT volume fraction, SWNT aspect ratio and beam slenderness ratio on the nonlinear frequency and on the phase trajectory plots for pre- and post-buckling states are studied.

Effect of Different Precursors Solution of NiO on the Properties of ZnO/NiO Nanocomposites Thin Films Grown by Spray Pyrolysis

In this paper, the influence of the precursors of nickel oxide (NiO) on the properties of ZnO/NiO nanocomposites thin films, grown by spray pyrolysis method, has been investigated. The nickel sulfate, nickel chloride and nickel nitrate have been used as precursors of NiO, each precursor has been mixed with Zinc oxide (ZnO)’ precursor to elaborate ZnO/NiO nanocomposites thin films with the method mentioned above. The aim of this paper is to confirm the similitude of precursors in the nanocomposites. For this reason, and to reveal this goal, some techniques were used as the structural analysis by X-ray diffraction (XRD) which a high intensity has been detected corresponds to the ZnO / NiO films with nickel chloride precursor, UV-Visible characterization depicts the presence of a maximum adsorption band appears in the ultraviolet range, the morphological characterization with Atomic Force Microscopy (AFM) reveals the roughness and the different grain size of particles, the big one of the latter agree, also, with to nickel chloride precursor used. The values of optical band gaps Eg are globally equal with high value noticeable agree with films that prepared with nickel chloride and zinc chloride precursors. The results obtained confirm the aim and a good agreement with the latter were found.

Physical and Magnetic Characterization of Hard/Soft SrFe12O19/CoFe2O4 Nanocomposite Magnets Made by Mechanical Alloying and Ultrasonic Irradiation

In this study, the particle sizes of SrFe12O19 in hard/soft SrFe12O19/CoFe2O4 nanocomposite magnets made using mechanical alloying and ultrasonic irradiation were investigated. SrFe12O19/CoFe2O4 nanocomposites were combined in a ratio of 75:25, with each magnetic material being prepared separately. SrFe12O19 powder was prepared from Fe2O3 and SrCO3 powder by mechanical alloying and ultrasonic irradiation for different times, 0, 3, 6, 9, and 12 h. Varying the ultrasonic time during the preparation of the SrFe12O19 samples resulted in differences in morphological characteristics, crystal structure, particle size, crystal size, microstrain, density, porosity, and magnetic properties. The longer the ultrasonic time, the crystal size and particle size decreases, the density increases, and the porosity reduction which affects the magnetic properties. SrFe12O19 after 12 h ultrasonic process reach Ms value = 61.29 emu/g. CoFe2O4 powder was produced from Fe2O3 and CoCO3 powder by mechanical alloying with a 10 h milling time. Furthermore, each SrFe12O19 sample was composited with CoFe2O4 powder by ultrasonic irradiation for 1 h and these composite samples also showed different characteristics, where there is an increase in Mr and Ms compared to the single SrFe12O19. The morphology, crystal structure, particle size, and magnetic properties of the samples were measured using scanning electron microscopy, X-ray diffraction, particle size analysis, and PERMAGRAPH. The crystal size and microstrain were calculated using a Williamson–Hall plot, and density and porosity were determined using Archimedes’ law.