Effect of 60Co γ-irradiation on structural and optical properties of thin films of Ga10Se80Hg10

Thin films of Ga₁₀Se₈₀Hg₁₀ have been deposited onto a chemically cleaned Al₂O₃ substrates by thermal evaporation technique under vacuum. The investigated thin films are irradiated by ⁶⁰Co γ-rays in the dose range of 50–150 kGy. X-ray diffraction patterns of the investigated thin films confirm the preferred crystallite growth occurs in the tetragonal phase structure. It also shows, the average crystallite size increases after γ-exposure, which indicates the crystallinity of the material increases after γ-irradiation. These results were further supported by surface morphological analysis carried out by scanning electron microscope and atomic force microscope which also shows the crystallinity of the material increases with increasing the γ-irradiation dose. The optical transmission spectra of the thin films at normal incidence were investigated in the spectral range from 190 to 1100 nm. Using the transmission spectra, the optical constants like refractive index (n) and extinction coefficient (k) were calculated based on Swanepoel’s method. The optical band gap (E_g) was also estimated using Tauc’s extrapolation procedure. The optical analysis shows: the value of optical band gap of investigated thin films decreases and the corresponding absorption coefficient increases continuously with increasing dose of γ-irradiation.     

Synthesis,Characterization and Properties of Single-Walled Carbon Nanohorns

Single-walled nanohorns (SWNHs) have been prepared by sub-merged arc discharge of graphite electrodes in liquid nitrogen. The samples were examined by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. Nitrogen and boron doped SWNHs have been prepared by the sub-merged arc discharge method using melamine and elemental boron as precursors. Intensification of Raman D-band and stiffening of G-band has been observed in the doped samples. The electrical resistance of the SWNHs varies in opposite directions with nitrogen and boron doping. Functionalization of SWNHs through amidation has been carried out for solubilizing them in non-polar solvents. Water-soluble SWNHs have been produced by acid treatment and non-covalent functionalization with a coronene salt. SWNHs have been decorated with nanoparticles of Au, Ag and Pt. Interaction of electron donor (tetrathiafulvalene, TTF) and acceptor molecules (tetracyanoethylene, TCNE) with SWNHs has been investigated by Raman spectroscopy. Progressive softening and stiffening of Raman G-band has been observed respectively with increase in the concentration of TTF and TCNE.     

Electrical Properties of Carboxyl Methylcellulose/Chitosan Dual-Blend Green Polymer Doped with Ammonium Bromide

This present work discusses dual-blend green polymer electrolyte (GPE)–based natural polymers, composed of carboxyl methylcellulose (CMC) and chitosan (CS), created by introducing various compositions of ammonium bromide (NH₄Br) as a dopant in the system. These GPEs were successfully prepared by the solution casting technique and characterized using electrical impedance spectroscopy (EIS). From EIS measurement, the highest room-temperature conductivity is 1.21 × 10^?5 Scm^?1 for the sample containing 20 wt.% of NH₄Br. Plot of the temperature dependence of the GPEs revealed that the system obeys the Arrhenius rule and was thermally assisted. Besides that, dielectric studies were also conducted and the data were analyzed using complex permittivity, ?^*, and complex electrical modulus, M*, to determine the sample with the highest conductivity value. Thus, this study confirmed non-Debye behavior in the sample.     

Thermal studies of furosemide–caffeine binary system that forms a cocrystal

Thermal techniques, differential scanning calorimetry (DSC), and hot stage microscopy (HSM) have been used to study the interactions between furosemide and caffeine that are known to form a 1:1 cocrystal. This system has been used as an example to study the probable mechanism of cocrystal formation when the individual components, which are polymorphic, are heated. The study indicates that the phase transition of the low temperature stable polymorph of furosemide initiates cocrystal formation. This result suggests increased mass transfer rate can trigger cocrystal formation. The binary phase diagram (composition–temperature plots) of furosemide–cocrystal–caffeine system was determined from the DSC curves. The results imply that the cocrystal forms eutectic with caffeine but not with furosemide. This study has thus exemplified the use of DSC in understanding binary phase system where the two components form a cocrystal.     

Polysaccharide‐Based Oleogels Prepared with an Emulsion‐Templated Approach

The preparation and characterization of oleogels structured by using a combination of a surface‐active and a non‐surface‐active polysaccharide through an emulsion‐templated approach is reported. Specifically, the oleogels were prepared by first formulating a concentrated oil‐in‐water emulsion, stabilized with a combination of cellulose derivatives and xanthan gum, followed by the selective evaporation of the continuous water phase to drive the network formation, resulting in an oleogel with a unique microstructure and interesting rheological properties, including a high gel strength, G′>4000 Pa, shear sensitivity, good thixotropic recovery, and good thermostability.     

Preparation of multiwall carbon nanotubes (MWCNTs) stabilised by highly branched hydrocarbon surfactants and dispersed in natural rubber latex nanocomposites

The performance of single-, double- and triple-chain anionic sulphosuccinate surfactants for dispersing multiwall carbon nanotubes (MWNCTs) in natural rubber latex (NR-latex) was studied using a range of techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. The conductivities of the nanocomposites were also investigated using four-point probe measurements. Here, MWCNTs were efficiently dispersed in NR-latex with the aid of hyperbranched tri-chain sulphosuccinate anionic surfactants, specifically sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14). This paper highlights that TC14 performs much better than that of the commercially available surfactant sodium dodecyl sulphate (SDS), demonstrating how careful consideration of surfactant architecture leads to improved dispersibility of MWCNTs in NR-latex. The results should be of significant interest for improving nanowiring applications suitable for aerospace-based technology.     

Miniaturization of GPS patch antennas based on novel dielectric ceramics Zn(1−x)MgxAl2O4 by sol–gel method

The need for miniaturization and weight reduction of GPS patch antennas has prompted the search for new microwave dielectric materials. In this study, a sol–gel method was used to prepare Zn_(1?x)Mg_xAl₂O₄ thin films and fabricate GPS patch antennas at a low annealing temperature (700 °C). X-ray diffraction (XRD) patterns, field emission scanning electron microscopy images, Fourier transform infrared spectra, and optical band gap analyses confirmed the nanostructure of (Mg/Zn)Al₂O₄. The XRD patterns displayed the characteristic peaks of (Mg/Zn)Al₂O₄ with a face-centered cubic structure. Mg addition decreased the crystallite size, surface morphology, and lattice parameters of the resultant films, evidently affecting their density and dielectric constant (? _r ). Based on the material investigated and microwave antenna theory, GPS patch antennas were fabricated using Zn_(1?x)Mg_xAl₂O₄ and then studied using a PNA series network analyzer. The fabricated patch antennas with different ? _r ceramics decreased in size from 12.5 to 10.8 cm². The patch antennas resonated at a frequency of 1.570 GHz and provided a return loss bandwidth between ?16.6 and ?20.0 dB; their bandwidth also improved from 90 to 255 MHz. The GPS patch antenna fabricated from Zn_0.70Mg_0.30Al₂O₄ showed an excellent combination of return loss (?20.0 dB), small size (10.8 cm²), and wide bandwidth (255 MHz). Therefore, addition of Mg improves antenna performance and decreases the dimensions of the device.     

Mononuclear High-spin Octahedral Cobalt(II) Complex with Positive Axial Magnetic Anisotropy: Synthesis,Crystal Structure,and DFT Studies

This article outlines the magnetic features of a new six–coordinate high-spin cobalt(II) complex cis-[Co^II(tmphen)₂(NCS)₂] ( 1 ) achieved via the reactions of cobalt(II) thiocyanate with 3,4,7,8-tetramethyl-1,10-phenanthroline. The complex 1 was thoroughly characterized by different analytical and spectroscopic techniques and further confirmed by single X-ray crystal diffraction pattern. Complex 1 is a neutral molecule and adopt highly distorted six-coordinate CoN₆ octahedral coordination sphere surrounded by two thiocyanate N atoms in cis locations and the equatorial plane is occupied by two imine N atoms from the two tmphen ligand while the remaining two imine N atoms reside in the axial positions. Magnetic susceptibility data of complex 1 revealed that the χ_ΜT values decrease significantly to a value of 1.49 cm³ · K · mol^–1 at 2.0 K on decreasing temperatures below 100 K, mainly ascribed to the significant spin–orbit coupling (SOC) of six-coordinate Co^II ions. Furthermore, a field-dependence measurement was performed at 2 K, which shows a positive curvature up to 27 kOe, while it becomes linear up to 2.01 Nμ_B, which authenticated the fact that only the lowest Kramers doublet of ground state is appreciably populated.     

N-methylferrocenyl-N-ethylhydroxy ammonium nitrate: synthesis,characterization, and sensitizer in dye-sensitized solar cells

Transition Metal Chemistry - A new ferrocene-containing hydronitrate salt with formula N-methylferrocenyl-N-ethylhydroxy ammonium nitrate has been synthesized and characterized using microanalyses,...