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In this study, surface plasmon resonance (SPR) technique has been utilized to characterize the optical properties of chitosan-graphene quantum dots (CS-GQDs) thin film and dopamine (DA). Theoretical fitting of SPR dips yielded refractive indices of DA solutions and CS-GQDs thin films, as well as the thickness of the thin film. For DA solution, n and k values were the same as deionized water for all concentrations. The values of n and k for CS-GQDs thin film were 1.6990 and 0.1302 respectively before contacting DA. The experimental SPR reflectance curves obtained using CS-GQDs thin film were shifted continuously to the right with increasing DA concentrations. After adsorption of DA molecules, both n and thickness of the CS-GQDs thin film increased, while the value of k decreased. This, in turns, enhanced the SPR sensitivity towards DA. The obtained results underscore the appropriate and sufficient potential of the used technique to measure refractive index variations in real-time when very low concentration was used (1 fM) with refractive index sensitivity of 10.186°/RIU.

Four series of CaO-ZnO-B2O3-SLS (CZBS) glasses have been synthesized by using waste materials which are eggshell (EG) and soda lime silica (SLS) glass. We utilized eggshells to source calcium oxide (CaO) in this work, whereas we utilized SLS glass to substitute silica. CZBS1, CZBS2, CZBS3 and CZBS4 are the glass series containing weight percentages of CaO (15%, 20%, 25% and 30%) and SLS (70%, 65%, 60% and 55%), respectively, with the addition of 10% of B2O3 and 5% of ZnO in each sample. A conventional melt and quenching method was applied in this work to fabricate the CaO-ZnO-B2O3-SLS glass system. The glass transition temperature (Tg) was determined using differential scanning calorimetry (DSC), which revealed that the Tg increased from 714 to 735 °C, as the CaO content increased. Meanwhile, the glass structural properties were investigated, revealing an amorphous nature with no sharp peak. The experimental elastic moduli obtained by acquiring ultrasonic speeds using the ultrasonic pulse-echo method were compared to the hypothetical elastic moduli obtained by direct estimation of the hypothetical model.

Chemical compounds such as polydimethylsiloxane (PDMS) and hydrogen silicone (HS) have been extensively used for fabricating medical phantoms due to its human tissue equivalency. This study aimed to evaluate the mass attenuation coefficient, effective atomic number, and other radiation attenuation properties of various polydimethylsiloxane samples and to verify the best material that can be used to simulate the kidney tissue. There are six samples of polymers in total, which are denoted as S0, S1, S2, S3, S4 and S5; these were 20/0/0, 16/4/0, 16/0/4, 12/4/4, 10/4/6 and 8/4/8, respectively with the composition of PDMS, HS and water. The Photon Shielding and Dosimetry (Phy-X/PSD) software (Phy-x.net) were used to estimate the attenuation properties, and the results were compared with the theoretical values obtained from the XCOM platform. The values of effective atomic number, mass attenuation coefficient, and linear attenuation coefficient, for PDMS S0 are reported to be the highest compared to all other samples, as S0 is based on 100% PDMS without any water and HS. The S1 sample, which only contained 20% of HS, was found to be higher than S2 sample, which had 20% water but without any HS. Hence, the water in samples significantly influences the radiation attenuation properties for photon energy. The Zeff for soft tissue and PDMS are different; their respective atomic numbers differ due to a presence of higher elements such as Si. This study reveals that the modified material, S1 samples constructed from 80% PDMS and 20% hydrophilic can be used to simulate the kidney in terms of the total mass attenuation coefficient, CT number and effective atomic number.

Zinc oxide nanorods (ZnO NRs) have gained considerable research interest due to their robust energy conversion efficiency. In the present work, ZnO NRs arrays were pinpointed to probe their electromechanical response under strain conditions. ZnO seed was sputtered on different substrates by radio frequency magnetron sputtering (RF) technique at 80 W constant power and 3.49 x 105 mbar base pressure. The X-ray diffraction patterns exhibit hexagonal wurtzite structure with preferred c-axis crystal directions in the (002) plane. The average thickness of the seed layer for all the samples was estimated at around 214.6 nm. Surface roughness and morphologies of the nanorods have been characterized by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM), respectively. FE-SEM images show homogeneous growth in different directions on substrates. The average diameters of ZnO NRs on silicon, glass and ITO were 51, 58 and 61 nm, respectively. The average length of all the nanorods on the substrates were measured around 1e2 mm. The local piezoresponse measurements conducted on two selected domain regions of the nanorod arrays had been characterized by piezoresponse force microscopy (PFM) to confirm the switching-piezoelectric behavior.

Efficient shielding materials are extremely important to minimize the effect of electromagnetic interference. Currently, various composite materials are being investigated with different shielding efficiencies reported. In this paper, a flexible and free-standing sodium-based chitosan (CH/Na) polymer with copper selenide (CuSe) filler was prepared for electromagnetic shielding. The CH/Na/CuSe polymer matrix was prepared via the direct casting technique at different wt% of CuSe, varying from 2 to 20 wt%. The polymer matrix was then characterised by using Fourier transform infrared (FTIR) spectroscopy to confirm the interaction between the CH/Na and CuSe. The XRD results revealed that the CH/Na/CuSe polymer was successfully formed. Improvement in the electrical conductivity was confirmed by an impedance spectroscopy measurement. The highest electrical conduction recorded was at 3.69 × 10−5 S/cm for CH/Na/CuSe polymer matrix with 20 wt% CuSe. An increase in total electromagnetic interference (EMI) shielding efficiency (SET) of up to 20 dB (99% EM power shield) was achieved, and it can be increased up to 34 dB (99.9% EM power shield) with the thickness of the polymer increased.

Lithium-ion batteries (LIBs) growing energy storage market demand having various carbon-based anodes has attracted much attention as a candidate for high-energy batteries due to its long cycling ability in electric vehicle (EVs) applications. As a part of the electrochemical redox process, excellent anode materials are required to enhance the energy density of the LIBs. Considering it is hard to replace industrial graphitic anodic materials, research focusing on new anode materials having carbon/Si prepared by electrodeposition and sol-gel and its electrochemical performance has been reviewed. Herein, novel carbonaceous and Si/ materials were studied using molten carbonates as an exciting new method of producing graphite composites for lithium-ion battery applications. The electrochemical properties as measured using galvanostatic charge-discharge, cycle ability, rate performance, and cyclic voltammetry were greatly enhanced by using the carbonate-derived anode compared to the commercial graphite. In this review, our focus is on carbon-based anode materials with the recent review of the last five years by compiling literature from 2016-2021.

Spinel LiMn2O4 is a positive electrode material with a robust structure. It has a three-dimensional network of channels for fast lithium-ion diffusion in state-of-the-art lithium rechargeable batteries. It is commercialized because of its high-power and cost-effective natural abundant element. However, its capacity fading and cycle performance, originating from Mn dissolution, still need improvement. In this review, the recent development of the effect of cation and anion doped into the spinel LiMn2O4 cathode material is thoroughly investigated. The effect of anion substitution on the morphology and electrochemical properties were investigated. Cation/anion substitution shows improvement in the structural stability and suppresses lattice deformation of the material. Finally, some insight into the future prospects for spinel cathode developments is provided.