The properties of high-strength concrete (HSC) containing rice-husk ash (RHA) and nanocalcium carbonate (nano-CaCO₃) is evaluated. For this purpose, various HSC samples containing 0–20% RHA and 0–1.5% nano-CaCO₃ were prepared and investigated for the slump, compressive strength, absorption, electrical resistivity, chloride penetration depth and sulphuric acid (H₂SO₄) attack resistance. Results indicated that by a ternary combination of Portland cement (PC) + 10% RHA + 0.5% nano-CaCO₃, it is able to produce HSC with 28 days compressive strength of 101.7 MPa, which was 15% higher than that of estimated for plain HSC. Additionally, substituting optimum level of nano-CaCO₃ in HSC containing RHA could improve the electrical resistivity and reduce the water absorption and chloride ion penetration depth compared with binary use of PC + RHA. A lower mass loss has been determined for the ternary combination of PC + RHA + nano-CaCO₃ at all immersion times in 5% H₂SO₄ solution as compared with plain HSC. Moreover, considering HSC samples exposed to H₂SO₄ solution at the age of 84 days, it can be seen that the presence of nano-CaCO₃ in HSC containing RHA did not necessarily contribute to a significant reduction in the crushing load loss percentage compared with the binary use of PC + RHA.

Application of tea oil in food products has been gained more and more attention for its nutritional advantages and functional properties. This research fabricated green tea seed oil nanoemulsions by the self-emulsification method through variation of oil and surfactant composition. Finally, in vitro antibacterial assay and antioxidant properties were investigated. The results showed that the sizes could be regulated through surfactant content (5–15 wt%) and composition (HLB 10.72–13.93) from 16.44 ± 0.01 nm to 329 ± 4.74 nm. With the increase of the content of green tea seed oil, the DPPH and total antioxidant capacity of the nanoemulsions were gradually improved. Meanwhile, the antibacterial assay was enhanced as the content of green tea seed oil increased from 0.5 to 1.5%. The inhibition zone increased continually to 7.56 ± 0.40 mm and 6.85 ± 0.59 mm when 1.5% oil was provided. The results could provide a reference to essential oils in the design of functional food-grade ingredients.

Microfabrication, electrical characterisation, and mathematical modelling of a non-spiral planar microcoil useful for wireless power transfer applications in biomedical devices are presented in this work. The fabrication method using the existing very-large-scale integration manufacturing process requires a single mask level, and a single metal level without any via enables direct integration with a complementary metal oxide semiconductor sensing circuitry. An analytical model of magnetic field distribution in a non-spiral microcoil is developed for the first time in this work, which satisfies the form of a Bessel function of the first kind. An electrical model of the non-spiral planar microcoil is also developed and compared with experimental results. Experimental results are in good agreement with the theoretical model. Based on the experimental results, using optimised coil geometry, a wireless power transfer link suitable for biomedical wireless power transfer applications is studied. The maximum possible value of coupling factor of the wireless link is found to be 60% for a small separation between the coil and the magnet whereas the minimum value of coupling factor is found to be below 10% for large separations. It is found that introducing Neodymium magnetic shield layer at the receiving coil enhances the coupling factor significantly.

In the present research work, novel nano-sized cubes of TiO₂ capped with the biomolecules of Tinospora cordifolia leaf extract have been successfully synthesised and characterised. UV–visible absorption spectrum shows the maximum absorption edge at a wavelength of 271 nm. Transmission electron microscope results reveal the development of nano-sized cubes with anatase phase confirmed from selected-area electron diffraction pattern. Further, X-ray diffraction study re-confirms the crystallinity and anatase phase evolution of TiO₂. Fourier transmission infrared and energy-dispersive X-ray spectrum spectra elucidate the presence of biomolecules on TiO₂ surface. The high photocatalytic activity of green synthesised TiO₂ is demonstrated through the degradation of a textile dye, neutral red. A total 93.4% of dye has been removed with high apparent constant value (K _appa = 0.00758 min⁻¹) under 120 min of short UV-light irradiation. Therefore, current work presents simple, low-cost, eco-friendly and hitherto unreported synthesis of TiO₂ nano-cubes using Tinospora cordifolia leaf extract that could pave the way towards highly efficient photocatalysts.

Pure Nickel (Ni) and Nickel–Palladium (Ni–Pd) alloy were electrodeposited on graphite surface via pulse electrolysis in dimethyl sulfoxide in form of rods and nanoparticles with a diameter of ∼100–350 and ∼10–35 nm, respectively. X-ray photoelectron spectroscopy (XPS) spectra of Ni 2p_3/2 region for these nanomaterials suggests on their surface Ni²⁺ precursor while after Ar⁺ ion-etching metallic nickel starts to be dominated. Both Pd⁰ and Pd²⁺ for XPS spectra of Pd 3d_5/2 and 3d_3/2 were observed after electrodeposition. Scanning electron microscope-energy dispersive X-ray and XPS analysis confirmed electrodeposition of nickel nanomaterials in non-aqueous electrolyte. Using a lower concentration of Ni²⁺ precursor, nanoparticles with an average particle size of ∼10–23 nm were prepared on a graphite surface.

A stacked double gate junctionless tunnel field-effect transistor (JL-TFET) has been proposed and examined the effects of interface trap charges (ITCs) by introducing both acceptor and donor charges at the semiconductor/insulator interface. The structure uses two isolated gates (polarity gate and control gate) over an n-type-doped silicon substrate to function as a TFET. The effect of ITCs has been analysed in terms of DC and analogue/radio-frequency performance using parameters such as transfer characteristics, electric field, electric potential, transconductance (g _m) for both conventional and gate stacked JL-TFET. Additionally, they have also analysed metrics used to measure the device linearity performance and intermodulation distortion such as higher-order transconductance coefficients (g _m2, g _m3) and figure of merit. All the simulations have been performed with the help of an Atlas device simulator.

In this work, a series of porous zinc oxide (ZnO) architectures were prepared by changing the concentration of trisodium citrate by using a green hydrothermal and calcination method, and the photocatalytic performance of the ZnO samples were investigated by using Rhodamine B as degradant under ultraviolet irradiation. The concentration of trisodium citrate had a great influence on the morphology, structure and optical properties of the ZnO samples, which together affected the photocatalytic activity. With the increase of trisodium citrate concentration, the morphology of as-prepared hexagonal wurtzite ZnO changed from flower-like to porous microsphere, and then formed bigger spheres which were more tightly assembled by nanosheets. The higher photocatalytic performance of ZnO microsphere prepared from 1 × 10⁻³ mol·l⁻¹ trisodium citrate solution was due to the hierarchical pore structure, its better ultraviolet light absorption and higher charge separation. Moreover, the mechanism of the dye photodegradation reaction was discussed.

Residuary quinoline is a potential risk for human health in the environment, and the adsorption process is an effective way to remove this residual antibiotic. In this work, a very common guar gum was carbonised to guar gum derived carbon, which demonstrated a rich porous structure and high Brunauer–Emmett–Teller surface area (990 m² g⁻¹) that endowed the quinoline antibiotic with a fast adsorption rate and excellent adsorption capacity. The nonlinear fitting parameters of the adsorption isotherm indicate that the Langmuir model can accurately represent the adsorption behaviour with a maximum adsorption capacity of 425 mg g⁻¹. The guar gum derived carbon shows great potential for the removal of antibiotics such as quinoline and other contaminants in contaminated water.

Multi-group orthogonal experiments cooperating MATLAB stimulation were employed to synthesise antimony-doped tin oxide (ATO) (Sb–SnO₂)-doped silica (ATO/SiO₂) composite powder with high conductivity and dispersivity analysis. Results suggested that the resistivity ranged from 3.9 to 300 Ω cm while the nano-silica doping amount ranged from 0 to 1.5% (mass ratio) under the best parameters of Sb-doped content of 9.5 mol%, 3 precursor wash times, calcination temperature of 750°C, gelling reaction temperature of 45°C and calcination time of 2 h. Both the ATO and ATO/SiO₂ particles were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscope studies to prove that the addition of silica could not only increase the specific surface area and resistivity of particles, but also reduce the agglomeration of particles. The relationship between conductivity and dispersion of composite powder (Sb–SnO₂−SiO₂) dominated by different nano-silica content could be simulated by the ‘logistic function model’, which has important guiding significance for the preparation of composite powders with prominent characteristics.

A microembossed copper microchannel heat sink was designed and fabricated for high-density cooling in electronics. The microchannel width and aspect ratio were investigated to find out the optimised channel size for microembossing. The fabrication method was based on bulk copper forming including tungsten die inductively coupled plasma etching, hot copper microembossing, inlet/outlet ports punching and sealing. The heat dissipation performances were tested by ceramic heater. The maximum temperature decreased to ∼37°C under different heat fluxes, with the maximum temperature decreased by 69.2% at 50 W/cm² heat flux. The equivalent heat transfer coefficient reached the value of 6492 W/m² K. High-power chip was used as heat source too. The maximum heat flux reached 304.8 W/cm² when the chip can still function properly at 90.5°C. High cooling performance with the micro-heat sink proves that microembossing by tungsten die is an alternative process for microchannel heat sink fabrication with batch production and low cost. Taking advantages of simple fabrication process and reutilisation of tungsten die, the technology shows promising potentials in high-density microcooling systems.

The development of medical imaging technology has led to progress in nanomedical diagnosis, prevention, and detection. In this study, the latest applications of single-mode imaging, dual-mode imaging and multimode imaging in nanomedicine are reviewed. Meanwhile, in the single-mode imaging section, several imaging techniques such as magnetic resonance imaging and computed tomography illuminate their respective characteristics and medical applications. In the part of dual-mode imaging, nanoprobes and nanodrug carriers as nanobiotechnology applications, which combined with dual-mode imaging are conducive to the accurate cancer diagnosis and efficient delivery of drugs, respectively. In the application of multimodal imaging, owing to the combination of treatment and multimodal imaging, functional diversity and fewer side effects are obtained. Each section outlines the current utilisation and potential of imaging in nanomedicine, illustrating the potential applications in the future. This review is supposed to provide some ideas for the multifunctional application and accelerate another technical leap of fusion imaging technology in medicine.

For the first time, the effects of adding hydrazine solution to tin-oxide sol–gel to be used as an electrode in high-performance supercapacitors have been studied. The mixed solution has been spin-coated on stainless steel foils as substrates followed by exposing to hydrogen plasma treatment. The results show the effectiveness of adding hydrazine to tin-oxide sol–gel, compared to pure tin-oxide sol–gel. The electrochemical tests such as cyclic-voltammetry and charge–discharge characteristics have been conducted, and the findings demonstrate the favourable contribution of adding hydrazine in increasing the capacitance of the supercapacitor. The physical properties of the tin-oxide material have been analysed by means of FESEM, XRD, TEM, FT-IR spectroscopy and Raman spectroscopy to have a better understanding of preparation procedure and better insight in material synthesis. The electrochemical tests demonstrate a high capacitance of 18 mF/cm² for the sample treated with hydrazine during the sol–gel processing which is around 40% higher than the merely prepared tin-oxide sample. The measured values for the capacitance versus rate show a rather linear correlation between these parameters, further corroborating an electric-double layer-based performance for such devices.

The present work details the synthesis of cobalt quantum-dots (Co QDs) with size downscaling to 1–2 nm and their applications in non-volatile memory (NVM) devices. The process of colloidal synthesis is simple and provides the control over a wide range of QDs size. The scaled-down colloidal Co QDs are applied for the NVM device fabrication. Colloidal synthesised Co QDs are spin-coated over silicon dioxide wafer for the fabrication of floating-gate NVM devices. Capacitance–voltage (C–V) and capacitance–time (C–t) measurements of the fabricated NVM device indicate a low voltage operation of device. A sweep voltages as small as 1.2–4 V lead to a flat band voltage shift of 0.35–1.5 V, evidencing the low operating voltage and low power NVM applications. Further, retention characteristics show a robust retention by fabricated NVM device. In addition, C–V measurements are done for the several samples in order to study the process repeatability. The work also is compared with the other processes for the floating gate memory device.

The influence of surface roughness on adhesion hysteresis of Cu thin films with different thickness was studied. The Cu thin films were fabricated using dc magnetron sputtering technology and their surface adhesion forces were measured using force-displacement curves of atomic force microscopy. The experiment results show that the unload curve exhibits obvious adhesion hysteresis and that the roughness and adhesion force have opposite change tendency. The theoretical analysis on the influence of thin film roughness to the adhesion hysteresis was carried out using the Johnson–Kendall–Roberts model. The results show that the load curve and unload curve constitute a closed curve and that the smoother the surface, the more obvious adhesion hysteresis, i.e. the rougher the surface, the less obvious adhesion hysteresis. The theoretical analysis results are in good agreement with the experimental results.

A reduced surface field (RESURF) AlGaN/GaN high-electron-mobility transistor (HEMT) with graded doping buffer (GDB) and slant back electrode (SBE) is proposed. In the GDB, the p-dopant density increases linearly both from top to bottom and right to left. The concentrated negative space charges in the lower-left corner of GDB attract the electric field lines from the channel and barrier towards the gate under OFF-state, which flats the electric field and enhances the breakdown voltage (V _br). Additionally, the low p-dopant density near the top of GDB achieves the device with low ON-state resistance (R _ON). The SBE flats the electric field along the channel above it and introduces a peak electric field near its edge. Simulation results show a V _br of 2150 V and R _ON of 7.05 Ωmm for the proposed device, compared with 1701 V and 7.73 Ωmm for the conventional back electrode RESURF HEMT (BE-RESURF HEMT) with the same gate -drain spacing. Moreover, due to the reduced depletion of 2DEG from the GDB, the proposed device shows slight increases in f _T and f _max (8.76 and 14.80 GHz), comparing with the conventional BE-RESURF HEMT (8.24 and 13.84 GHz).