International Journal of Nanoscience

Nanoparticle Lead sulfide was synthesized via simple chemical method and deposited on glass substrates at different substrate temperatures by thermal evaporation technique. The synthesized nanoparticle PbS was analyzed and confirmed by X-ray diffraction (XRD), Scanning electron microscopy SEM with EDX and thermogravimetry. The structural, optical, morphological and electrical properties of the deposited films were studied using XRD, UV-Vis, Raman, SEM with EDX, atomicforce microscopy AFM and Hall Effect measurements. The thickness of the deposited samples was measured using thickness profilometer. The Raman shift in the peak occurs toward lower energy with increasing substrate temperature deposited lead sulfide. The Z-scan study with open aperture was carried out at 532 nm using 5 ns laser pulse on the deposited films which shows that nonlinear absorption arises from saturable absorption process. The deposited PbS film exhibits p-type conductivity in Hall measurement.

Silver molybdate nanoparticles were successfully prepared by the hydrothermal process. Polyaniline–silver molybdate nanocomposites were prepared by in situ chemical oxidative polymerization technique. Silver molybdate nanoparticles and the polymer samples were characterized by conductivity studies, Fourier transform infrared spectra (FT-IR), UV-visible spectra, photoluminescence spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The electrical conductivity of PANI-Cl^- increases when doped with silver molybdate nanoparticles and follows the percolation threshold.

In this paper, a correlated double sampling (CDS) technique is proposed in the design of a delta sigma analog-to-digital converter (ADC). These CDS techniques are very effective for the compensation of the nonidealities in switched-capacitor (SC) circuits, such as charge injection, clock feed-through, operational amplifier (op-amp) input-referred offset and finite op-amp gain. An improved compensation scheme is proposed to attain continuous compensation of clock feed-through and offset in SC integrators. Both high-speed and low-power operation is achieved without compromising the accuracy requirement. Also this CDS delta sigma ADC is the most promising circuit for analog to digital converter because this circuit reduces noise due to drift and low frequency noise such as flicker noise and offset voltage and also boosts the gain performance of the amplifier. Further, the simulation results of this circuit are verified on using a "cadence virtuoso tool" using spectre at 45 nm technology with supply voltage 0.7 V.

Silver nanoparticles (SNPs) have been successfully prepared using sol–gel method by annealing the sample at 550°C for 30 min. The SNPs were not confirmed by X-ray diffraction (XRD) analysis when the annealing temperature was considered at 450°C. They were also not confirmed without calcination of the sample. The physical mechanism of silver clusters formation in the densified silica matrix with respect to thermal treatment has been understood. The presence of silver metal in the silica matrix was confirmed by XRD analysis and TEM image of the samples. The average size of nanoparticles dispersed in silica matrix was determined as 10.2 nm by the XRD technique. The synthesized nanocomposites were also characterized by UV-Visible spectroscopy with a peak in the absorption spectra at around 375 nm. The distribution of particle size has been reported here in the range from 8 nm to 25 nm by TEM observations of the sample prepared at 550°C. The spherically smaller size (≈10 nm) SNPs have reported the surface plasmons resonance (SPR) peak less than or near to 400 nm due to blue-shifting and effect of local refractive index. Without annealing the silica samples the absorption spectra does not show any peak around 375 nm. The FTIR spectroscopy of the three types of samples prepared at different temperatures (room temperature, 450°C and 550°C) has also been reported. This spectra have provided the identification of different chemical groups in the prepared samples. It has been predicted that the size of SNPs by XRD, UV-Visible and TEM results have agreed well with each other. It may be concluded that formation of SNPs is a function of annealing temperature.

Boron nitride nanotubes (BNNTs) are of immense importance due to their many interesting functional features, notably biocompatibility and piezoelectricity and dominant mechanical strength as compared to carbon nanotubes (CNTs). The reliable implementation of these structures in an application is inherently related to its mechanical characteristics under external loads. The presence of defects in these structures severely affects the tensile properties. The effect of presence of point, line and Stone–Wales (SW) defects on the tensile behavior of BNNTs is systematically investigated by applying reactive force fields in molecular dynamics (MD) framework. Reactive force fields effectively describe the bond breaking and bond forming mechanism for BNNTs that are important for a practical situation. The Young's modulus of single-walled (10,0) BNNTs of length 100 nm has been found to be nearly 1.098 TPa, in good agreement with the available reports. The presence of defects has been shown to significantly reduce the tensile strength of the tube, while the number and separation of the defects effectively contribute to the percentage reduction. In addition, the effect of tube diameter and also the initial temperature are observed to strongly influence the tensile characteristics of BNNTs, indicating increased auxetic behavior than CNTs.

In this work, Langmuir films of organized assemblies of β-lactoglobulin (βLG) with 1-ethyl-3-methyl imidazolium ethyl sulfate (IL-emes) have been characterized at air/water interface using surface pressure-specific area isotherms and dilational rheology. The protein in the IL-mediated assembly shows excellent packing at the interface and is stable as seen in circular dichroic spectroscopy. These spread films on nickel chloride were transferred as Langmuir–Schaffer films of βLG and βLG+IL-emes and used as template for designing nanoclusters of nickel oxide. The nanoclusters have been characterized using transmission electron microscopy (TEM) and powder XRD. While pure protein template gives needle-shaped structures, the IL-mediated template gives spherical shapes of hexagonal nickel oxide in the range 30 nm to 40 nm. Presence of ionic liquid seems to slow down the growth of the cluster and also prevents aggregation of the clusters.

Alloyed CdSe_0.3Te_0.7nanocrystals (NCs) were prepared by a thermochemical method using Thioglycolic acid (TGA) as a capping agent molecule. X-ray diffraction (XRD) and Transmission electron microscopy (TEM) analysis demonstrated hexagonal phase NCs with an average size of around 2.5 nm. Synthesized NCs indicated a narrow band emission with a peak located at 561 nm. Nonlinear optical (NLO) properties of the CdSe_0.3Te_0.7NCs have been investigated by z-scan technique using Continuum Wave He–Ne laser. The nonlinear absorption coefficient and nonlinear refraction index were obtained in the order of 10^-2 and 10^-8, respectively. The results revealed that these NCs exhibit strong NLO properties effects such as self-defocusing and two photons absorption.

In the current study, γ-Fe₂O₃/SiO₂/PCA/Ag-NPs hybrid nanomaterials were successfully synthesized and characterized. At first, prepared γ-Fe₂O₃ core nanoparticles were modified by SiO₂ layer. Then they were covered by poly citric acid (PCA) via melting esterification method as well. PCA shell acts as an effective linker, and provides vacancies for conveying drugs. Moreover, this shell as an effective capping agent directs synthesis of silver nanoparticles (Ag-NPs) via in situ photo-reduction of silver ions by sunlight-UV irradiation. This system has several benefits as a suitable cancer therapy nanomaterial. Magnetic nanoparticles (MNPs) can guide Ag-NPs and drugs to cancer cells and then Ag-NPs can affect those cells via Ag-NPs anti-angiogenesis effect. Size and structure of the prepared magnetic hybrid nanomaterials were characterized using FTIR and UV-Vis spectra, AFM and TEM pictures and XRD data.