Porous graphitic carbon nitride (g-C₃N₄) has been synthesised by means of one-step calcinations of dicyandiamide for efficient photocatalysis under visible light irradiation (λ > 400 nm). Scanning electron microscopy images demonstrate that the as-prepared photocatalyst calcined at 650°C is a porous structure. The UV–vis diffuse reflectance spectra show that the optical absorption for the porous g-C₃N₄ is more intensive than for common g-C₃N₄ calcined at 550°C. The enhanced generation of the photocurrent under visible light irradiation (λ > 400 nm) is observed by using the porous g-C₃N₄. The results of the photocatalytic experiments under visible light irradiation reveal that the photocatalytic degradation of methylene blue using the porous g-C₃N₄ is higher than common g-C₃N₄, showing the advantage of the structure for efficient photocatalysis. The presence of the calcinations temperature is presumed to play a key role in adjusting the textural properties.

The static contact angle calculation for superhydrophobic surfaces is systematically investigated. The water drop profiles with different volumes, contact angles, rotational angles and apex coordinates are numerically generated based on the Laplace equation. Thereafter, the goniometry, θ/2 method, circle and ellipse fitting algorithms and an improved axisymmetric drop shape analysis-profile (ADSA-P) algorithm are used to calculate the static contact angle. The results reveal that the contact angle errors by the θ/2 method, circle and ellipse fitting algorithms increase with the drop volume/contact angle. The goniometry will introduce significant error. The ADSA-P algorithm can accurately obtain the contact angles (error < 0.3°) for the drop profiles regardless of the water drop volume, contact angle, rotational angle and apex coordinate. The ADSA-P algorithm should be selected to calculate the static contact angles for the superhydrophobic surfaces. Static contact angle measurements of the superhydrophobic surfaces validate the aforementioned analysis.

The investigation of photocatalysis by efficient visible-light-active photocatalysts has been of interest in both the science and the engineering fields. The nitrogen (N) doped KAl_0.33W_1.67O₆ (KAW) and KCr_0.33W_1.67O₆ (KCW) are prepared by the solid state method. Urea was used as a nitrogen source. These materials were characterised by thermo gravimetric analysis, powder X-ray diffraction, scanning electron microscopy, energy dispersive spectra, X-ray photoelectron spectroscopy (XPS) and UV–visible diffuse reflectance spectroscopy (UV–vis DRS). Both the N-doped materials crystallised in a cubic lattice with space group Fd3̄m. The XPS analysis of the N-doped KAW (N-doped KCW) show the characteristic peaks belonging to K 2p, Al 2p (Cr 2p), W 4f, O 1s and N 1s along with C 1s. The bandgap energy was deduced from their UV–vis DRS profiles. The photocatalytic degradation of the methylene blue solution was investigated in the presence of these oxides. Compared with their parent materials, nitrogen doped KAW and KCW samples exhibit ∼230 and ∼130% increase, respectively, in visible light-induced photodegradation of methylene blue.

Fe₃O₄ nanoparticles have been successfully synthesised through co-precipitation of FeSO₄ and FeCl₃ by adding a solution of NH₄OH. The products are characterised in detail by multiform techniques: scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. The results show that the phase structure of the Fe₃O₄ nanoparticles is a spinel structure of pure Fe₃O₄ with the particle size ranging from 40 to 50 nm. The obtained Fe₃O₄ nanoparticles have been employed as electrode materials for electrochemical sensing H₂O₂. The detection sensitivity of the sensor was 0.77683 µA mM⁻¹ and the detection limit was estimated to be about 1 mM.

A facile method of synthesising nanosized lithium-rich layered material with uniform particle size by a one-step hydrothermal approach has been developed. The effect of lithium ion concentration on hydrothermal products has been investigated. At low or high lithium ion concentration, products with poor layered characteristic were obtained. Under the optimum lithium ion concentration of 2.5 M, the obtained product has an Li_0.94[Li_0.14Ni_0.26Mn_0.60]O₂ stoichiometry with plate-like morphology and a uniform particle size of ∼80 nm. The Brunauer-Emmett-Teller surface area measurement indicates that it possesses a surface area of 35.60 m² g⁻¹. The electrochemical tests show that the as-prepared nanomaterial Li_0.94[Li_0.14Ni_0.26Mn_0.60]O₂ can acquire a high performance with an initial discharge capacity of 278 mAh g⁻¹ at 30 mA g⁻¹ and a corresponding capacity retention of 95% after 40 cycles. Moreover, it can even deliver 185 mAh g⁻¹ at 1500 mA g⁻¹, exhibiting excellent rate capability which makes it suitable for high power lithium-ion batteries.

Electrospinning is a simple and efficient method for creating continuous nanofibres that present unique physical, chemical, electrical, magnetic and optical properties. However, its wide applications in various fields are restricted by the limitation that conventional electrospinning typically produces two-dimensional (2D) nanofibrous membranes with limited thickness. To address this issue, an electrospinning system is developed to construct 3D nanofibrous structures by using a tunable collector on which a diameter-adjustable cage rotor was mounted. The thickness of the nanofibrous structures is greatly increased by reducing the cage rotor diameter in certain time intervals during electrospinning. For comparison, different poly(lactic-co-glycolic acid) nanofibrous structures were manufactured by using the conventional and the proposed methods, respectively. The results indicated that the improved system is able to construct 3D nanofibrous structures with high porosity, stable geometrical morphology and good mechanical property. The work is expected to be useful for fabricating functional nanofibrous materials for a variety of applications.

To obtain high quality patterns in ultraviolet roll-to-roll (R2R) imprinting lithography in the atmospheric environment with industrial resins, air bubble defects and the resulting distortion should be avoided in the process. In this reported work, the formation mechanism of the bubble defects is studied systematically with experiments and numerical analysis. The results show that the unsuitable resin coating method mainly contributes to the bubble defects in resin. On the basis of the above conclusions, an improved coating method is proposed in order to reduce the bubbles in the R2R process. This improvement can be applied to the replication of high quality patterns in R2R imprinting with low-cost industrial resins.

One-dimensional coaxial nanofibres with a core (Ni_0.5Zn_0.5Fe₂O₄)/sheath (ZnO) were produced by coaxial electrospinning and calcining. The core/sheath structures were clearly visible by transmission electron microscopy (TEM), because of, respectively, putting chloroform and glycerin into the core and the sheath precursor solutions. Their core/sheath structures, chemical compositions and phase analysis were investigated by means of high-resolution TEM, scanning electron microscopy and X-ray diffraction. The results show that its mean diameter is 30 nm; the thickness of the shell is 8 nm; and ZnO promotes the axial growing of Ni_0.5Zn_0.5Fe₂O₄.

SnS nanostructures were synthesised by simple vacuum thermal evaporation without any catalysts using tin chips and sulphur as the starting materials. The morphology was characterised by scanning electron microscopy and transmission electron microscopy (TEM) equipped with a high-resolution TEM. It was found that the as-prepared products were mostly tube shaped with a uniform geometry. The length of the nanostructures was several μm, the outer diameter and the thickness of the tubes was about 40–70 and 10–20 nm, respectively. The phase was analysed by X-ray diffraction and confirmed that the as-prepared products were of the orthorhombic phase. The photoluminescence spectra showed two emission bandcentres at 555.4 nm (2.24 eV) and at 785.0 nm (1.58 eV), which indicates that the SnS nanostructures could be used to prepare visible or an infrared light emitter or other optical devices.

A fabrication process to integrate SU-8 check valves on a microfluidic platform based on a printed circuit board (PCB) is reported. The process allows the fabrication and the integration of these devices with PCB substrates at the same time, thus obtaining a PCB/SU-8 hybrid system with no need of assembly. The SU-8 valves fabricated as proof of concept are composed of four or two suspensions and a plate. The fabrication results confirm the validity of the procedure of the fabrication to build these kinds of microstructures. The behaviour of the valves has experimentally been studied showing good results, demonstrating that the integration of these microelectromechanical systems devices with the PCB technology is compatible.

A modified biomimetic micropump based on the stomatal transpiration principle is presented. The micropump is designed to have a layer of SU-8 microporous membrane and a layer of hydrophilic microporous ceramics, which reflects the natural plant stomata and mesophyll cells. The evaporation characteristics of the different stomata are analysed qualitatively by an established model. There is a positive connection between the stomata evaporation flux and the micropump flow rate. Corresponding experiments on micropump flow rate are conducted. The presented micropump has favourable assembly and reuse properties. The results indicate that the water vapour distribution in the stomata has a trend of edge effect. It also shows that the fluid flow rate in the micropump changes regularly with the stomata size and spacing.

Quantum-dot cellular automata (QCA) is a novel computational paradigm which utilises the quantum mechanism to encode and process bit information. The switching characteristics of the QCA majority gate are evaluated by using the proposed probability model. All kinds of probabilities are achieved by solving the time-independent Schrodinger equation. The simulation results reveal that the majority gate switches at a higher correct probability when the cell distance and the size decrease. Cell miniaturisation would raise a significant implication in how to realise reliable QCA fabrication. In addition, the results also illuminate that majority output has different probabilities when the inputs change. Therefore, to analyse the QCA circuit reliability by using the probability model, all the input combinations must be considered.

In this reported work, low loading Pt–Ru alloy nanoparticles (PtRu NPs) have been highly dispersed on reduced graphene oxide (PtRu/RGO) via an auto-power adjusting microwave-assisted one-pot reaction process. The transmission electron microscopy result shows that PtRu NPs with a mean size of ∼ 2.99 nm decorated uniformly on RGO. The prepared PtRu/RGO is used as an electrocatalyst for the methanol oxidation reaction (MOR). Compared with the commercial carbon-supported Pt–Ru alloy electrocatalyst, the PtRu/RGO composites demonstrate higher electrochemical active surface area and excellent electrocatalytic activity towards the MOR, such as higher peak current density, lower onset potential and long-term stability. It is deduced that the good performance of the PtRu/RGO towards methanol oxidation could be attributed to the characterised RGO support which provides more effective support and enhances the utilisation of the PtRu clusters, and to the highly dispersed small Pt–Ru alloy NPs resulting from the special microwave heating mode and lower synthesis temperature, which subsequently leads to a valid bifunctional mechanism between Pt and Ru. The present study proves that the PtRu/RGO composites could be a promising alternative catalyst for direct methanol fuel cells and this effective preparation method can be widely applied to other metal/bimetal NPs.

Single-crystalline chlorine-doped cadmium selenide (CdSe) nanobelts (NBs) with a wurtzite structure were synthesised by using CdSe and InCl₃ powder as sources via a co-evaporation approach. The investigation of the performance of the field-effect transistors fabricated from Cl-doped NBs shows n-type conduction behaviour and enhanced conductivity (1–70 S/cm). Furthermore, it is found that the photoconductivity (illuminated by a white light with a power density of 1.3 mW/cm²) increases with the enhancement of the conductivity. Photoconductive analysis reveals that the Cl-doped NBs show excellent photoresponse properties, with responsivity of 8.87 × 10⁵ AW⁻¹ and a corresponding external quantum efficiency of 1.74 × 10⁶ when illuminated under a 650 nm light and biased 1 V. In addition, the electrical properties of the Cl-doped NBs can be influenced by changing the ambiance, which is caused by their surface states.

Nanosized Ce-doped lutetium aluminium garnet (LuAG:Ce) phosphors have been synthesised by a solvothermal method using ethylenediamine as the solvent and metal nitrates as the starting materials. The phase development, the morphology and the luminescent properties of the prepared phosphors were investigated with X-ray diffractometry, transmission electron microscopy and photoluminescence spectra, which showed that phosphors of high phase purity resulted after heating for 8 h at a low temperature of 230^oC. This powder possesses good dispersivity, suffers little or no aggregation and has an average grain size of 220 nm with narrow size distribution, hence, it may be exploited for the fabrication of LuAG:Ce optical ceramics. Its excitation and emission spectra have also been examined, which confirms the transitions between the 4f and the 5d states of the Ce³⁺ ions as the photoluminescence mechanism. The photoluminescence decay showed almost identical components compared with the LuAG:Ce single crystal, which further proves that the obtained nanosized phosphors have been well crystallised.