The photosensitive azobenzene-tethered DNA material provides an ideal force for DNA nanomachines. This work demonstrates the process of light-driven DNA strand displacement by physical and mathematical models. By data fitting, the strand displacement reaction rate constants under different sequence designs are discussed in detail. The results showed that the Gibbs free energy induced by azobenzene is around 2.52 kJ mol⁻¹, which would hinder the light-driven strand displacement reaction. Increasing the length of the sticky ends can increase the displacement rate exponentially, but the displacement rate will not increase when it exceeds 12 bases.

Octahedral jarosite was successfully prepared without extra template using a novel hydrothermal route based on the redox reaction between KMnO₄ and (NH4)₂Fe(SO₄)₂·6H₂O. The mass ratio of (NH₄)₂Fe(SO₄)₂·6H₂O/KMnO₄, reaction time, and reaction temperature play key roles in forming octahedral crystals. The chemical composition and microstructure of as-prepared octahedral jarosite were characterised by X-ray diffraction, scanning electron microscopy, energy dispersive spectrum, high-resolution transmission electron microscopy, and selective area electron diffraction. The formation mechanism of octahedral jarosite was discussed preliminarily.

Abruptness at tunnelling junction is a vital issue with doped tunnel field-effect transistor (TFET) to achieve improved electrostatic characteristics. This task is more problematic for charge plasma TFET (CP-TFET) because of large tunnelling barrier at the channel/source interface. In this regard, an effective approach has already been employed through implantation of a horizontal metallic splint (HMS) inside the dielectric region near channel/source joint for improved electrical behaviour of CP-TFET. However, placement of a vertical metal splint (VMS) provides contact for HMS and gate electrode, which gives magnificent analogue/DC characteristics for newer structure. Combination of HMS and VMS (i.e. double metal splint (DMS)) increases electron density at channel/source junction for improved electron tunnelling rate compared with only HMS structure. In this regard, a complete comparative analysis of DMS CP TFET (DMS-CP-TFET) is performed between CP-TFET and HMS-CP-TFET. Furthermore, consequence of length and work-function variation of DMS and HMS on DC/RF parameters is investigated in device optimisation part of this work.

The layered LiNi_1/3Co_1/3Mn_1/3−x Mg _x O₂ (x = 0, 0.01, 0.02, 0.03) were synthesised by a stepwise co-precipitation method. The effects of Mg substitution on the crystal structure of the synthesised powder have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) mapping. Their electrochemical properties were evaluated by charge/discharge and electrical impedance spectroscopy tests. The results of XRD, SEM and EDS mapping characterisation indicated that all the modified cathode materials with their Ni, Co and Mn components doped by magnesium without destroying the crystal structure. Electrochemical characterisation confirms that the materials have optimal cycling performance and the least capacity loss under the 2% Mg-doping. The specific capacity of the LiNi_1/3Co_1/3Mn_1/3−0.02Mg_0.02O₂ was 180 mAh g⁻¹ at 0.1 C and 138 mAh g⁻¹ at 8 C, which compares favourably to 175 mAh g⁻¹ at 0.1 C and 121 mAh g⁻¹ at 8 C for the LiNi_1/3Co_1/3Mn_1/3O₂. The LiNi_1/3Co_1/3Mn_1/3−0.02Mg_0.02O₂ also exhibited the best electrochemical performance with capacity retention of 89.4% after 50 cycles at 0.2 C between 2.5 and 4.3 V.

A combination of nanohole array and gold nanoparticles (Au NPs) was fabricated on the c-Si substrate. The substrate is then optically characterised through reflectance spectra. Reduction in reflectance around 68.91% was observed in the wavelength range of 300–1100 nm for the hybrid nanostructured surface. The reduction in reflectance is attributed to a gradual change in refractive index owing to the nanohole array and the localised surface plasmon resonance of the Au NPs.

With tannin as both reducing and stabilising agents, high yield single-crystalline silver (Ag) nanowires were synthesised in a simple solution system at 45–55°C. No additional capping or co-reduction agent was required. The length of the Ag nanowires could be up to several tens of micrometres and the average diameter was 50 nm. By adjusting the temperature and pH values of the reaction system, nanoparticles were obtained as the main product. The tannin protected Ag nanowires could be used for the detection of Pb(II) ions with high sensitivity and selectivity and the detection limit could be as low as 10⁻⁸ M. This detection assay is more practical in application because of its green and low cost preparation and longer storage time at ambient conditions.

Novel chitosan/alginate/silica ternary aerogel beads were successfully prepared by the orifice-coagulation bath with the ambient pressure drying method and utilising chitosan, sodium alginate, and tetraethoxysilane as the initial raw materials. The morphologies, porosity characteristics, and dye absorbencies of the ternary aerogel beads were also investigated, respectively. The obtained samples are milky light solid, the size of the spherical aerogel is uniform, its diameter can be controlled ∼5 mm, the specific surface area is 169.4 m² g⁻¹, pore size distribution is concentrated in the 2–100 nm, which is a typical nanofilamentous network structure. Meanwhile, the ternary beads were tested for dyestuffs adsorption; the results showed that the obtained samples exhibit excellent adsorption properties, and can keep good sphericity as a class of novel adsorbents.

Preferred (002)-oriented aluminium nitride (AlN) films by direct-current (DC) magnetron sputtering on Si (100) substrate were prepared at various deposition pressure (0.12–0.5 Pa). The influence of pressure on the surface morphology, crystal structure and optical properties of AlN thin films was discussed the with the methods of X-ray diffraction, atomic force microscopy and stress analyser, respectively. Optical properties were studied by ellipsometer and Fourier transform infrared spectrometer. It was observed that the AlN films tended to be preferred (002)-oriented when the pressure was decreased and the value of full width at half maximum is 0.325° when the pressure was kept at 0.12 Pa. the tensile stress, refractive index, and the density of Al–N bonds decreased with increasing the sputtering pressure from 0.12 to 0.5 Pa. This work demonstrated the influence of sputtering pressure on the structural and optical properties of the AlN films deposited on Si (100) substrate, the gallium nitride epitaxial film on Si (100) substrate was expected to be realised using sputtered AlN as the buffer layer.

Ethylene propylene diene monomer (EPDM) is a polymeric material widely used for high-voltage insulation. This work reports the dielectric and thermal properties of EPDM co-filled with micro- and nano-BN particles. EPDM composite samples with different micro and micro/nano co-filled contents are prepared by melt-blending and followed by hot press application. Measurements were made including broadband dielectric spectroscopy, thermogravimetric analysis and thermal conductivity. Experimental findings indicate that Micro-25 wt% + Nano-5 wt% performs better in terms of dielectric loss and conductivity whilst the dielectric constant is measured lower in Micro-29 wt% + Nano-1 wt% relative to the equivalent micron filled Micro-30 wt%. Moreover, the initial degradation temperature and final residual masses of co-filled composites are found considerably higher. The thermal conductivity of EPDM is highly influenced by the introduction of co-filled set of particles and it is measured about 0.465 W/m.K in Micro-29 wt% + Nano-1 wt% which is 18% higher than Micro-30 wt%. It is likely that the denser packing geometry due to co-filled set of particles inside the EPDM matrix improves the dielectric and thermal properties which make such composites more attractive for electrical insulation applications.

Herein, silver (Ag)-based urchin-like E-graphite carbon nitride/titanium dioxide (E-g-C₃N_4/TiO₂) ternary composite was successfully synthesised via hydrothermal process and it showed excellent photocatalytic activity. The large interfacial contact between three-dimensional (3D) urchin-like TiO₂ (UT) and g-C₃N₄ leads to high photocatalytic activity, compared with pure 3D UT. To enlarge the response of light and enhance the charge carriers’ transfer, the Ag nanoparticles with average sizes of 13 nm were loaded on the surface of g-C₃N₄/TiO₂. Photodegradation test results of RhB shown that the 3% Ag-based urchin-like E-g-C₃N₄/TiO₂ composite has the highest catalytic activity, which reaches 97.98%. Thus, the material has a promising application for the degradation of organics.

The thermal buckling response of nanotubes with rotational restraints is investigated using a Timoshenko beam model with non-local elasticity theory. Two trigonometric (Fourier) series are selected to analyse the thermal buckling of the non-local Timoshenko nanotube with rotational restraints. Explicit equations are obtained for the boundary values with a coefficient matrix. In particular, the new method can be degenerated to the non-local Euler beam model by assigning proper value to the shear correction factor. The main advantage of the present technique is its capability of dealing with deformable or rigid supporting conditions. Several numerical examples are solved to asses proposed approach reliability. The results show that thermal buckling including the thermal effects are lower than those without the thermal effects when the temperature rises. The rotational restraint springs have significant effects on the buckling response of nanotubes.

This work integrated zero-valent copper (ZVC) onto the surface of zeolitic imidazolate framework (ZIF) to form hybrids of ZVC/ZIF-8 as a non-noble catalyst for catalytic reduction of PNP as a reliable model reaction. The ZVC/ZIF-8 exhibited superior catalytic properties and good recyclability after the fabrication. 6%ZVC/ZIF-8 hybrids complete the reduction process in 2 min with a rate constant estimated to be 2.39 min⁻¹. The study’s findings explored a simple and powerful way to incorporate metal ions into the backbones of open framework materials without losing their properties.

Nowadays, flexible strain sensors applied in the fields of health care and electronic skin have been widely studied and applied. In fact, the temperature characteristic of flexible strain sensors based on metal nanomaterials is rarely concerned. In this work, the ohmic and tensile properties of the flexible strain sensor based on silver nanowires–polydimethylsiloxane were tested and it was found that the sensor has good ohmic characteristics and a maximum gauge factor of 536.98. In addition, the resistance of the sensor was affected little by temperature when the temperature environment of the sensor was changed, and the resistance temperature coefficient of the flexible strain sensor is −1050 ppm/°C. Furthermore, it was found that the sensor was sensitive to minute strain when the sensors were applied to the two application tests of strain and pulse.

Full-spectrum-responsive AgI/WS₂ composites as an efficient photocatalyst have been synthesised by an in-situ growth of AgI on the surfaces of WS₂ nanosheets. The photocatalytic activities of the samples were evaluated by degradation of rhodamine B dilute solution under visible light irradiation. Experimental results showed that the introduction of WS₂ nanosheets could enhance light absorption, photocatalytic activity, and recyclability of the pure AgI in the region of visible and infrared light. Moreover, the degradation efficiency of the as-synthesised AgI/WS₂ composites exhibited the trend of first increased and then decreased with increasing the amount of WS₂ nanosheets. When the usage of WS₂ nanosheets was 7 wt%, the as-prepared composites possessed the maximum of 91.2% in 30 min. Furthermore, after three cycles of degradation, it could still degrade 89.0% of rhodamine B, obviously higher than 11.4% of pure AgI. In addition, a possible degradation mechanism of the as-synthesised AgI/WS₂ hybrids was provided.

Sesame-husk-like porous SnO₂ nanocylinders were synthesised by a refluxed technique followed calcination in air. Served as anode materials for lithium-ion batteries, porous SnO₂ nanocylinders showed a higher initial discharge capacity of 2411.3 mAh/g at 100 mA/g compared with non-porous SnO₂ nanocylinders (2043.6 mAh/g). Moreover, porous SnO₂ nanocylinders demonstrated better cyclability and rate capability in comparison with non-porous SnO₂ nanocylinders. For porous SnO₂ nanocylinders, a higher discharge capacity of 414.5 mAh/g after 50 cycles at a current density of 100 mA/g can be successfully delivered, and a higher reversible capacity of 248.3 mAh/g at 1000 mA/g current density after 100 cycles could be retained. The improved electrochemical performance is mainly ascribed to the unique porous nanostructures.

Pure and manganese (Mn)-doped zinc oxide (ZnO) (0, 1, 2 and 4 wt%) nanoparticles are synthesised by refluxing method. The as-synthesised nanoparticles are characterised by X-ray powder diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy (EDS). The results show that pure and Mn-doped ZnO nanoparticles have a hexagonal wurtzite structure and the (101) diffraction peaks position of Mn-doped ZnO shift toward the smaller value of diffraction angle compared with pure ZnO powders, confirming that the Mn²⁺ were well incorporated into ZnO crystal lattice. Moreover, Mn doping also restrained the growth of particles and the size decreased from 14.9244 to 13.1196 nm with the increase in doping concentration from 0 to 4 wt%. The EDS analysis for 2 wt% Mn-doped ZnO confirms the presence of Mn in ZnO nanocrystal. The dielectric measurements show that Mn-doped ZnO ceramics exhibit higher dielectric constant, while dielectric constant and dielectric loss increased continuously with the temperature increased. In addition, 2 wt% Mn-doped ZnO ceramics showed the high dielectric constant (23 × 10³) and low dielectric loss (0.95) at 125°C after sintering at 1000°C for 2 h.

According to the gradual changes of the microstructure of superalloys during harsh service condition of turbine blades and the detrimental effects of these changes on the mechanical properties of superalloys, performing of a rejuvenation heat treatment (solution treatment + aging process) on ex-serviced superalloys is necessary. In this work, the aging heat treatment was conducted on a serviced single crystal ZHS32 superalloy in the temperature range of 950–1150°C. It was found that while performing the aging process at 950 and 1050°C for 10 h did not provide appropriate conditions for the nucleation and growth of primary ϒ′ phases, conducting aging at the temperature of 1150°C for 10 and 16 h yields to the formation of ϒ′ precipitates with the desired cuboidal morphology. The comparison of the microstructure of the rejuvenated samples with the un-rejuvenated samples confirms that with applying this procedure, the size of strengthening ϒ′ precipitates reduces and the volume fraction of these phases considerably increases, which yields to the recovery of the superalloy microstructure and improvement of its mechanical properties such as hardness.

Nanostructured polymeric film has wide range of applications in different fields. However, the existing processes of fabrication of nanostructures on polymer surfaces are limited to very small area and throughput of the processes is very low. In order to solve this challenge, the indigenous hot embossing setup was developed which is capable of patterning micro-nano structures on large area. In this work, the steps for the development of hot embossing setup are discussed. The setup requires nanostructured mould, copper-chromium block, pencil heaters and temperature controlled system (thermostat and thermocouple). Two different types of nanostructures (groove and pillars) were successfully replicated on polystyrene film. The fabricated nanostructures were characterised using field emission scanning electron microscope and atomic force microscope. The dimensions of fabricated nanostructures are close to the mould dimensions with few defects (shrinkage defects). The wettability test was performed using goniometer on plain and structured polystyrene film to study the effect of structures on the wettability of the surface. It was observed that the hydrophilic (water droplet contact angle: 43°) polystyrene film got converted into hydrophobic (water droplet contact angle: 102–112°) nature. The fabricated structured surfaces have shown antibiofouling property which was confirmed through plate counting method.

The results of a comparative investigation on microstructure and magnetic characteristics of silane magnetic nanocomposites coated with silver nanoparticles (AgNPs) are presented. The authors used tetraethyl orthosilicate (TEOS) with (3-aminopropyl) triethoxysilane (APTES) to improve the antibacterial properties of AgNPs. On the basis of this approach, TEOS-APTES polymer was made by the sol–gel method. A layer of the polymer was set on the magnetic core of Fe₃O₄ NPs and then AgNPs were coated on the TEOS-APTES surface. Therefore, the core–shell structure of the Fe₃O₄/TEOS-APTES/Ag polymer nanocomposite was synthesised. To characterise the crystal morphology, structure, and size of nanocomposites, various techniques and experiments including Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscope, dynamic light scattering, and transmission electron microscope were used. Vibrating sample magnetometer showed the magnetic properties of the samples. Finally, antibacterial activity against Gram-negative and Gram-positive bacteria including Escherichia Coli ( American Type Culture Collection (ATCC) 35218), Salmonella typhimurium (ATCC 14028), Staphylococcus aureus (ATCC 292113) and Bacillus cereus (ATCC 14579) was showed by the disc diffusion analysis. The results indicated the uniform distribution of AgNPs on the polymer surface. Fe₃O₄/TEOS-APTES/Ag nanocomposite showed much better antibacterial activity in comparison with AgNPs only.

A multi-bit memory device was fabricated using a ferroelectric polymer. For multi-bit storage, a capacitive-type memory was configured to have two different thicknesses: a thinner sub-capacitor to represent the polarization reversal at a lower voltage and a thicker sub-capacitor that allows the two sub-capacitors to operate in different voltage ranges. The thin film was composed of a single ferroelectric polymer film and the thick film was composed of a hybrid film of a ferroelectric polymer and a photosensitive polymer. The photosensitive polymer reacted with ultraviolet light, so it was patterned by a conventional lithography process. The external voltage was divided into two layers, the ferroelectric layer and the photosensitive layer, which resulted in polarisation reversal at a higher voltage region. The most important feature of this work is that no vacuum equipment was used in the manufacturing process of the memory device. In the manufacturing process of the conventional multi-bit memory device, vacuum equipment was required to remove the polymer film. Therefore, the size of the substrate is limited and the productivity is inevitably lowered. The proposed multi-bit memory device and its fabrication process will be useful because it has many advantages in terms of productivity compared to existing processes.

The vacuum breakdown critical condition of individual carbon nanotube (CNT) during field emission was investigated experimentally using the in-situ field emission combined scanning electron microscope system. The results showed that the critical breakdown electric field of CNT was related to its length and diameter. CNT which has a shorter length and larger diameter could bear higher electric field. The underlying mechanism was attributed to the heat dissipation ability of CNT. A smaller length and larger diameter CNT has better heat dissipation. The results met with the theoretical calculations and helped to understand the physics mechanism of vacuum breakdown of CNT during field emission in a visual perspective.

This study proposed a rapid and reliable approach for the bonding of thermoplastic-based microfluidics with a new, low-cost, low toxic, and transparent ultraviolet (UV) curable adhesive as the intermediate layer between thermoplastic plates. After laser fabrication of microchannels on the surface of the polymethyl methacrylate (PMMA) substrate, the UV curable adhesive layer is applied between the substrate and cover plate; a flushing process is then conducted for the removal of the adhesive residuals inside the microchannel. Finally, a UV exposure with the wavelength of 365 nm is applied for the crosslinking of adhesives to finish the bonding process. Several microfluidic devices were fabricated and tested for the demonstration of the proposed technique, and the bonding strength was carefully measured with different UV exposure duration. The characteristics of the contact angle and UV–visible spectroscopy of the UV adhesive coated surface are also provided in this study. In addition, a simple biocompatibility test of the UV curable adhesive-coated polymer surface is also conducted in this research to confirm the low toxicity of the adhesive layer. The proposed bonding techniques are broadly applicable to achieve a rapid, low-cost, optically clear, and low toxic bonding for thermoplastic-based microfluidics.

The development of flexible photodetectors is believed to have great potential for future optoelectronic applications, such as biomedical imaging and smart wearable systems. Here the work proposes a simple and low-cost approach for integrating a flexible and wearable ZnO ultraviolet (UV) photodetector using polyester fabric as the platform for the first time. The ZnO nanowires coated polyester fabric was prepared by a low-temperature hydrothermal approach. They measured the performance of the photodetector in terms of I–V characteristics and time-resolved photocurrent. The results showed that the as-fabricated ZnO UV photodetector presented great reliability. Additionally, the working mechanism of the device was also discussed.

A novel step high-k metal–oxide–semiconductor field-effect transistor (step HK-MOSFET) is designed with the step high-k insulator based on the HK-MOSFET concept for the first time. In the off-state, the step HK insulator enhances the lateral field component in the drift region due to the new electric field peak, which increases the depletion of the drift region and leading to the low specific on-resistance (R _{on, sp}) of step HK-MOSFET compared with the conventional HK-MOSFET. Meanwhile, the various thicknesses of the HK insulator modulates the vertical electric field distribution in the drift region, which increases the breakdown voltage (BV) of step HK-MOSFET compared with the conventional vertical double diffused MOSFET and HK-MOSFET. The results show that the simulated BV of step HK-MOSFET is increased from 639 V of the conventional HK-MOSFET to 736 V with the same drift region length of 42 μm or decreased the requirement of permittivity for the HK region to 120 ɛ ₀ from 230 ɛ ₀ with the same BV of 600 V.