The adsorption isotherm of the single walled carbon nanotubes (CNTs) is measured. The mathematical models for calculating pore size distribution (PSD) are modified. The PSD of sample is determined using Horvath–Kawazoe (KH), Saito and Foley (SF) and Barrett–Joyner–Halenda (BJH) methods. An average potential function has been determined inside the slit-like and cylindrical pores. Since all of the regions of CNTs have same type that adsorbed nitrogen in the same conditions, the calculated PSDs from HK, SF and BJH models have same trend in both interior and exterior surfaces. By adding the adsorption term on outer surface, HK, SF and BJH models have been developed hence the pore volume increased.

A series of MnO₂/carbon nanofibres (CNFs) catalysts were prepared by a facile co-precipitation method for low-temperature selective catalytic reduction (SCR) of NO with NH₃. These catalysts were characterised by the techniques of specific surface area measurements (BET), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and H₂ temperature-programmed reduction (H₂-TPR). The XRD, FESEM and TEM results showed that the CNFs were surrounded by MnO₂ nanoflakes. Compared with the MnO _x /CNFs catalyst prepared by the wet impregnation method, the MnO₂/CNFs catalysts exhibited better low-temperature SCR activity at low temperature. The XPS results indicated that a higher concentration of Mn⁴⁺ and more surface oxygen species exited on the surface for 8% MnO₂/CNFs catalyst. The H₂-TPR profiles displayed that the 8% MnO₂/CNFs catalyst presented stronger low-temperature reducibility than the MnO _x /CNFs catalyst. Based on the abovementioned favourable properties, the 8% MnO₂/CNFs catalyst has an excellent performance in the low-temperature SCR of NO with NH₃.

Low ON current and conduction for the negative gate-to-source voltage are the major drawbacks of the steep subthreshold slope tunnel field-effect transistor (TFET). Low work function on the source side of gate contact, high-κ gate dielectric and highly doped layer (delta doping) helps to enhance the ON current of the device. Whereas, low work function of gate electrode on the drain side and low-κ gate dielectric is used to eliminate the problem of conduction for the negative gate-to-source voltage. In the same concern, an analytical model for potential distribution of tri metal hetero gate dielectric delta doped TFET is developed by solving the two-dimensional (2D) Poisson's equation. Moreover, the extraction of electric field is performed by the developed potential model. However, model of drain current for the device is based on the Kane's band-to-band tunnelling generation rate. Finally, the verification of the developed model is performed with the 2D technology computer aided design ATLAS simulation results.

Herein conductive elastomers by homogeneous distribution of multi-walled carbon nanotubes (MWCNTs) in a styrene-co-butadiene-co-styrene (SBS) triblock copolymer matrix is reported. The inherent π–π stacking ensures nearly single-layer adsorption of the SBS molecules on the surfaces of MWCNTs, translating into reliable interfacial interactions. The resulting MWCNT/SBS nanocomposites are highly elastic and conductive. It is believed that this finding opens up a new way to fabricate conductive elastomers holding great promise as superior piezoresistive sensors that may integrate a ‘touch’ function in wearable electronics and computers.

An approach to decrease the P-doping density of graphene and increase the mobility of graphene field-effect transistors (GFETs) is reported. With a layer of natural aluminium oxide (natural-AlO _x ) thin film covered on the surface of graphene, the Dirac point voltage of the GFETs decreases 25 V while it experiences the mobility increase of 42 cm²/(V s) after exposure in the atmosphere for 1 month. To understand this phenomenon, other two situations are researched, the Dirac point voltage of the identical GFETs with no thin film on graphene increases more than 15 V and its mobility decreases 90 cm²/(V s) after 1 month. The last situation is that the Dirac point voltage and the mobility have no significant changes with an AlO _x deposited by electron beam evaporation (Al₂O₃-EBE) on graphene. These phenomena indicate that the natural-AlO _x thin film is capable of reducing p-type impurities on the graphene and bringing the better reliability to the GFETs.

A simple strategy was presented for fabricating a Prussian blue (PB)/chitosan (CHIT)/multi-walled carbon nanotube (MWCNT) composite. A simple chemical reaction was used to form PB nanoparticles on the surface of an electrode modified with CHIT–MWCNTs. Scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize the composite. PB–CHIT–MWCNTs were employed to construct an electrochemical hydrogen peroxide (HP) sensor. Tests showed that the sensor exhibited excellent electrocatalytic ability toward the reduction of HP. The amperometric response was linear with concentrations of HP in the range of 1.0 µM–0.5 mM, with a detection limit of 0.1 μM (S/N = 3). In addition, this sensor showed excellent selectivity, reproducibility, and stability, and it was satisfactorily applied for HP detection in real samples.

Nanocrystalline MgO particles with a cubic phase structure have been synthesised via ionic liquid (IL)-assisted solid-state reaction. The necessary characterisations such as XRD, EDS, FTIR, SEM and TEM have been carried out to investigate the obtained materials. The results show that the synthesised MgO consisted of a large quantity of sphere-like nanocrystals with average particle size of ∼26.3 nm, and had high crystallinity and narrow particle size distribution. Compared with solid-state reaction method, this method has the advantages of fast reaction rate and high yield. This indicates that IL-assisted solid-state reaction appears to be a promising method for the manufacture of nanometre MgO in industry.

Mn₃O₄ nanostructure aerogels have been successfully synthesised through an epoxide-driven sol–gel method with thioacetamide as precursors, followed by lyophilising (freeze drying). The prepared nanostructures were characterised by power X-ray diffraction pattern, scanning electron microscopy, energy dispersive X-ray analysis, surface area measurement (Brunauer–Emmett–Teller) and high-resolution transmission electron microscopy. The cauliflower-like and spheroidic morphologies Mn₃O₄ nanostructure aerogels can be successfully synthesised under different experimental conditions. The growth mechanism for different nanostructures is proposed. The cauliflower-like Mn₃O₄ aerogel exhibited higher adsorption capacity for methylene blue and phenol than the spheroidic Mn₃O₄ aerogel. In addition, the cauliflower-like Mn₃O₄ aerogel is a novel co-catalyst which is more effective for oxidative carbonylation of phenol to diphenyl carbonate. It may be attributed to the largest surface area and the nanostructure of the cauliflower-like Mn₃O₄ self-assembled by small nanoparticles. This work points out the way to develop a novel and more active self-assembled nanostructure aerogel co-catalyst for oxidative carbonylation of phenol to diphenyl carbonate.

Chromium(VI), a kind of migratory heavy metal pollutant, does not only accumulate in the soil in huge amount, but it can also migrate to the deep layer soil and even contaminate the groundwater. The migration pattern of water in the unsaturated silt loam is studied. Then the dynamic leaching characteristic of Cr(VI) is observed. Finally, through the indoor soil column leaching experiment, the influence of adding nano-aluminium oxide (Al₂O₃) into the soil column on the migration of Cr(VI) in the silt loam is analysed. In unsaturated silt loam, water in it apparently affects the Cr migration. The deeper the soil layer is, the lower the Cr(VI) concentration is. With the drip irrigation going on, the Cr(VI) concentration in the soil increases constantly until it fundamentally reaches the saturated adsorbance of the soil. With nano-Al₂O₃ added into the column, the migratory rate of Cr(VI) in the soil decrease obviously, which is probably because of the space steric effect and adsorption characteristics of nano-Al₂O₃. Therefore, nano-Al₂O₃ can be utilised as a preferable material to reduce the migration rate of Cr(VI) of soil and groundwater. The research results can supply the theoretical basis to the research of heavy metal pollution in the unsaturated soil.

Polyacrylamide (PAM)-encapsulated clay nanoparticles (NPs) were successfully synthesised by conventional emulsion polymerisation for solving the aggregation matter of nanoscaled clay. A novel nanofluid based on PAM has been developed and its’ attributes have been experimentally tested as an optimised solution. The frequency, sonication time effect, NPs and polymer concentration on the constant salinity and particle size (PS) distribution of samples was investigated. The solutions of polymer at different frequencies (10, 20 and 30 kHz) were treated with ultrasound for different times (5 and 15 min). The results showed that increasing sonication time decreased mean diameter of nanoclay mass and also showed with an increment range of frequency in specified range improved rheology and dispersion of the solution. Clay NPs were found to have a positive effect on the stability of samples.

Flexible pressure sensors offer the advantages of flexibility, low cost, and easy to large area fabrication, and they have wide applications in many fields. This work proposes a flexible capacitive pressure sensor that exhibits a sandwich-like structure, a good performance, and a simple process. Multi-walled carbon nanotube (MWNT) is used to fabricate the two electrodes of the sensor because this low cost material possesses good mechanical and electronic properties. Meanwhile, MWNT naturally forms numerous micro–nano structures that can enhance the sensitivity of a sensor. In addition, the dielectric layer of the sensor composed of parylene C (poly(chloro-p-xylylene)) is sandwiched between the two electrodes. The experimental results show that the pressure sensor demonstrates high sensitivity and a rapid response. The average sensitivity is 1.33 kPa^–1 at a pressure that ranges from 0 to 758 Pa and the response time reach to millisecond level. Given that low cost, good property and simple process, the sensor has wide application prospects in electronic skins, health monitoring devices, and other wearable electronic products.

To improve the profile quality of three-dimensional microstructures, an improved method was proposed in real-time maskless lithography based on digital micromirror device. First, to calculate the spatial distribution of exposure dose for the target profile in design, the relations of the exposure dose and the development depth were investigated. Moreover, a suitable development time was obtained. Second, an improved slicing strategy based on equal-arc algorithm was proposed to reduce the profile error. Different from traditional equal-expose-dose method, this method generated slicing layers with equal arc-length instead of equal-exposure dose. Such an approach has advantages in obtaining a series of suitable section patterns adapting to the curvature variation of the design profile. Finally, an aspheric microlens array was fabricated with this method and the equal-exposure-dose method. Results showed that the resulting microstructure profile by their method was more consistent with the design profile with the same slicing numbers. Moreover, results also showed that the method used can obtain as good profile quality as that of the equal-exposure-dose method with only a half of slicing numbers. This indicated that the proposed method is feasible for achieving good profile quality with slicing efficiency improved remarkably.

Fe₃O₄@SiO₂-SO₃H nanocomposites were successfully synthesised as the efficient magnetically separable solid acid catalysts for an esterification reaction. The resultant catalysts were characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, vibrating sample magnetometer (VSM), and nitrogen physical adsorption analyses [Brunauer–Emmett–Teller (BET) theory]. The catalytic activities of as-prepared Fe₃O₄@SiO₂-SO₃H nanocomposites were also investigated for the esterification of n-butyl acetate and isoamyl acetate. The acid esterification rate was confirmed by gas chromatography. The results showed that the Fe₃O₄@SiO₂-SO₃H nanocomposites can be as candidate cataysts for the concentrated H₂SO₄ for the esterification reaction of n-butyl alcohol or isoamyl alcohol. More importantly, the magnetic catalysts can be easily separated from the reaction system by a magnetic bar and reused at least three recycles without significant degradation of their activities.

In this research work, a light and perspiration stability enhancer for the reactive azo-dyes based on amino silicon oil (ASO) containing zinc oxide nanoparticles (ZnO-NPs) was fabricated. The fabricated samples were characterised by Fourier transform infrared spectroscopy, and the microstructural morphologies of cotton fabrics were observed by scanning electron microscopy. The light and perspiration stability was represented by the colour difference value (ΔE _CMC), and the light stability was calculated by the ultraviolet protection factor (UPF) value. The experimental results indicated that the ZnO-NPs dramatically improved the light and perspiration stability of all the reactive azo-dyes; the size of ZnO-NPs was decreased by the addition of the coupling reagent, [γ-(2,3-epoxypropoxy)propyl] trimethoxysilane (KH-560), resulting in the significant improvement of the light and perspiration stability. However, the ASO accelerated the yellowing of reactive azo-dyes due to its easy oxidation of activated hydrogen atoms, especially under high temperature. Further study disclosed that the fluoride-ASO with less activated hydrogen atoms significantly improved the light stability.

This work investigates the effect of channel engineering on the short channel performance of considered sub-20-nm 3D NAND flash memory. Here, the threshold voltage roll-off (ΔV _th), subthreshold swing and drain induced barrier lowering metrics is studied to evaluate the short channel effects (SCEs) for the examined device. The effect of variation in doping density on SCEs of proposed channel engineered NAND flash memory is also studied. Based on the observation, a thin layer of high doping concentration in the centre of the channel, covering 25% of channel area, has been found to improve the SCE of NAND flash memory compared with the device with uniform channel doping while maintaining sufficient drive current.