This reported research analyses and compares the bandwidth and absolute frequency response of a multi-layer graphene nanoribbon (MLGNR) and a multi-walled carbon nanotube (MWCNT) at local, semi-global and global interconnect lengths. The transfer function of the driver-interconnect-load system is obtained by representing the interconnect line with an equivalent single conductor model of either a MLGNR or a MWCNT. Using absolute frequency response, it is observed that the bandwidth of the MLGNR is higher by almost ten times and four times in comparison to the MWCNT for local and global interconnect lengths, respectively.

The aim of this reported work was to develop and characterise a soy lecithin-based self-microemulsifying drug delivery system (SMEDDS) of resveratrol to enhance its oral delivery. Using high-performance liquid chromatography, the solubility of resveratrol in various materials was determined. The effects and the ratios of the oil, surfactant and co-surfactant on forming an efficient and stable SMEDDS were investigated using pseudo-tertiary phase diagrams. The oil content, soy lecithin content and drug loading were optimised. The optimal formulation was composed of greoil gtcc, Cremophor EL, 1,2-propanediol, soy lecithin and resveratrol (16.1/46/23/6.9/8, %w/w). The final SMEDDS was characterised by particle size, zeta potential and by transmission electron microscopy. The dilution volume in various aqueous media had some effect on the particle size. An in-vitro release test showed a complete release of resveratrol from the SMEDDS in approximately 180 min. The stability investigation results indicated that the formulation was stable for 12 weeks.

Poly(methyl methacrylate) (PMMA) microparticles doped with natural dyes such as paprika and chlorophyll have been prepared by the solvent evaporation technique. A mixture of paprika and chlorophyll in different ratios was also doped with microparticles. The distribution of the diameter of particles spreads in the range of 3–7 μm. UV–visible spectroscopic studies have shown that the absorption wavelength is shifted to a longer wavelength region when the paprika content increases in the dopant mixture. The nonlinear optical properties of the samples were investigated. It is found that the coloured particles have remarkable optical nonlinearities in the nanosecond regime because of the interaction of double bonds in PMMA with the delocalised π-electron system of dyes.

Boron nitride nanotubes (BNNTs) were dispersed in an ethyl alcohol solution with polyvinylpyrrolidone (PVP) and Triton X-100 (TX100) as dispersants. The influence of the dispersant content on the dispersity of BNNTs was researched. The dispersion system was characterised by means of a UV–vis spectrophotometer, scanning electron microscopy and transmission electron microscopy. The results indicated that the dispersion effect of TX100 was better than that of PVP. The optimal addition of TX100 and PVP were 3 and 2 wt%, respectively. The precipitation of BNNTs was 8.6 and 12.6% after 48 h, respectively, with PVP and TX100. The disperse mechanism of TX100 and PVP was steric hindrance stabilisation.

A novel hydrogen peroxide (H₂O₂) biosensor was constructed based on Fe₃O₄ magnetic nanoparticles (MNPs) and horseradish peroxidase with graphene–chitosan composite material as a matrix. Fe₃O₄ MNPs were synthesised by chemical co-precipitation with sodium citrate as surfactant. Fourier transform infrared spectroscopy and transmission electron microscopy were applied for the characterisation of the obtained Fe₃O₄ MNPs. The conductivity of different composite films was researched by electrochemical impedance spectroscopy and the electrocatalytic properties of the H₂O₂ biosensor were studied by cyclic voltammetry. Under optimal conditions, experimental results indicated that the biosensor could electrocatalyse the reduction of H₂O₂; the reduction peak current had a good linear relationship with the concentration of H₂O₂ from 2.49 × 10⁻⁵ to 1.67 × 10⁻³ mol/l (R = 0.9990). The detection limit was 3.05 × 10⁻⁶ mol/l (S/N = 3). This novel biosensor showed good sensitivity, stability and repeatability for H₂O₂ detection.

A novel, fast, sensitive and practically solvent-free solid phase extraction method based on the adsorption of cetyltrimethylammonium bromide onto the surface of Fe₃O₄ nanoparticle adsorbent was developed for the quantitative determination of naproxen in biological fluids. The adsorbent was characterised by a transmission electron microscope, an X-ray diffractometer and Fourier transform infrared spectroscopy techniques. The main factors affecting the adsorption efficiency of the analyte such as the surfactant amount, pH value, desorption conditions, extraction and desorption time, sample volume, amount of Fe₃O₄ nanoparticles and ionic strength were evaluated and optimised. No clean-up steps were necessary for the determination of the drug in biological matrices because of the direct analysis of the eluate by liquid chromatography/UV, which is matrix-effect free. Under optimum conditions, naproxen was quantitatively determined and the linear range of the method was 0.1–700 ng ml⁻¹ with a correlation coefficient of 0.9993. An enrichment factor of 198 was obtained by extracting 200 ml of the sample solution. The detection limit was 0.01 ng ml⁻¹ and relative standard deviations (RSD %) for 20 and 150 ng ml⁻¹ were obtained as 2.9 and 2.3%, respectively. Finally, the proposed method was successfully applied to the determination of naproxen in human plasma and urine samples.

The etching characteristics of the commonly utilised Si (100) facet at high temperatures near the boiling point in surfactant-modified tetramethylammonium hydroxide (TMAH) solutions are investigated. Solutions of 25 wt% TMAH are selected because of the etching stability and the rate of addition of the surfactant Triton-X-100 [C₁₄H₂₂O(C₂H₄O)n, n = 9–10] ranges from 0.01 to 1% v/v. The etching rates of Si (100) facets close to the boiling point are three to four times higher than those at 80°C in the surfactant-modified 25 wt% TMAH solutions. In particular, at 115°C, the very near temperature of the boiling point, the silicon sample possessing a high etching rate of 1.45 μm/min and the smooth etched Si (100) surface with an average roughness of about 1 nm is obtained. Moreover, the samples do not demonstrate much undercut difference at the etched convex corners near the boiling point. These results are useful for the fabrication of microelectromechanical systems and indeed provide an efficient etching method for industry products.

An on-chip spectral surface plasmon resonance (SPR) optical sensor with a silver nanoparticle (Ag NP) array has been designed. Dextran (Dex)-capped Ag NP (Dex-Ag NP) arrays were initially self-assembled on the gold (Au) sensing film. The large perturbations and increased penetration depth of the evanescent field, which is caused by the use of the Dex-Ag NP array self-assembled on the Au sensing film, can effectively enhance the SPR spectral shift response. Compared with the bare Au sensing film configuration, the Au sensing film with a Dex-Ag NP array configuration improves sensitivity from 5492 to 6613 nm/RIU.

A ‘black silicon’ (BS) surface with low reflectance was fabricated by a standard pulsed deep reactive etching technology at room temperature. Aiming for a better understanding, a systematic experiment was conducted by varying the etching window size and bias power duty cycle. The samples were measured and analysed by a scanning electron microscope, the Bruker Optical Profiler and a UV-3400 spectrometer. It was observed that a broad scale range of the surface structures formed on the surface. With the duty cycle at 0.5, only about 100 nanometre scale replicable silicon cones formed on the surface, but as the duty cycle decreased to 0.25, the height of the silicon forest sharply increased to about 10 µm, leading to a low reflectance of 0.9% in the visible range for the surface. To clarify the reason for this trend, the bias effective voltage (BEV) was measured and it was confirmed that the BEV would decrease from 100 to 47 V with the duty cycle adjusted from 1 to 0.25. This suggested that this decrease in BEV leads to a reduction of ion energy and ion flux, and then modifies the fabricated structures. Besides, it was found that the broad etching window area only had a maximum promotion of 20% to the scale of the BS, indicating this method was almost free of loading effect.

Blood typing is a critical test for blood transfusion and many medical procedures. Described is a disposable microfluidic blood typing chip with a simple fabrication process. The chip allows one to use human whole blood directly so that the operation sequence of a manual polybrene technique for blood typing can be conducted automatically. In addition, the determination of the extent of red blood cell agglutination can be analysed by software. The feasibility of this chip was demonstrated by ABO blood typing tests using antibody screening cells and freshly drawn venous blood samples. From the pixel count of agglutination, the chip provided correct blood typing results. This proposed microfluidic chip has the merits of smaller consumption volumes of reagents. Moreover, the simple fabrication process of the chip results in low fabrication cost.

Microstructured materials assembled from organic small molecules through non-covalent interactions have been relatively less explored but are a very fascinating field. A surfactant-assisted self-assembly process was applied to fabricate two-dimensional (2D) sheet-like microstructures of (E)-3-(3-oxo-3-phenylprop-1-enyl)-2,3′-biimidazo[1,2-a]pyridin-2′(3′H)-one (OPBIPO) radicals. The obtained results indicate that compared to the bulk OPBIPO counterpart, the coercive force of a 2D OPBIPO microsheet sample is enhanced, which can be attributed to the morphology anisotropy of microsheet structures. In addition, the photoluminescence spectra show that the emission intensity of the microsheet sample is higher than that of the bulk material. This surfactant-assisted self-assembly technology will provide useful information on the fabrication of organic radical microstructures with novel morphology-dependent magnetic behaviours.

The biosynthesis of silver nanoparticles from Aspergillus flavus (A. flavus) was observed by the brown colour formation of fungal filtrate because of the reduction of silver ions to nano form. The UV scan of the filtrate revealed absorption peaks at 430 and 360 nm, which correspond to silver nanoparticles and inorganic phosphate, respectively. The simultaneous increase in the absorption of both peaks, at each successive recording revealed that the synthesis of nanoparticles is accompanied with the release of inorganic phosphate. The mechanism could possibly involve inactive phosphorylated nitrate reductase, which converts into the active dephosphorylated form during its contact with silver ions by releasing inorganic phosphate. The enzyme may then reduce Ag⁺ ions to silver nanoparticles (Ag⁰). Inorganic phosphate production was noticed only in A. flavus, A. niger and A. terreus as no peak at 360 nm was observed in filtrates of Fusarium oxysporum and Trichoderma reesei. Powder-X-ray diffractometry analysis revealed four peaks for 2θ values which correspond to a face-centred cubic crystal structure. The Fourier transform infrared spectrum indicated the presence of various functional groups. Transmission electron microscope analysis showed nanoparticle sizes of between 3 and 25 nm. Atomic force microscope images showed different shapes of nanoparticles at various concentrations of substrate. Optimum conditions for the biogenesis of silver nanoparticles were found to be a temperature of 30°C, pH 5.0, 0.5% NaCl and 1.5 mM AgNO₃.

Ce_0.05SnS₂/graphene (GNS) nanocomposites were synthesised via the hydrothermal method and sintering. The structure and electrochemical performance of the materials were characterised using X-ray diffraction, field emission transmission electron microscopy and electrochemical measurements. The flower-like Ce_0.05SnS₂ particles with a petal size of 50–100 nm were distributed on graphene sheets. The Ce_0.05SnS₂/GNS-2 composites exhibited an initial discharge capacity of 1638.3 mAh g⁻¹ at 0.5 C, a retention capacity of 707 mAh g⁻¹ after 50 cycles, and an improved rate capability because of the support of the nanographene. After their sintering, the Ce_0.05SnS₂/GNS nanocomposites displayed better electrochemical performance than before sintering.

A hybrid structure with higher linearity to compensate the thermal refraction effect based on a ruby microsphere resonator is proposed and has been realised. The thermal refractive effect of the hybrid structure is theoretically and experimentally demonstrated, which showed that it is limited by the diameter of the resonator and the Q factor. By increasing the diameter, the transmission spectrum experiences a transition from blueshift to redshift induced by thermal absorption and when it is equal to a specific value the thermal refraction effect can be reduced or even eliminated. Experiments showed that there is no shift with varying input optical power since the thermal refraction of ruby can be completely compensated at the diameter of the microsphere d = 1.5 μm and Q = 2.3 × 10⁶ when the KD-310 coated thickness is 60 μm. This reported work shows that the structure could be used to improve stability and is sensitive in high-Q resonators for applications in laser, biosensor and nonlinear optics.

The self-organisation of magnetite nanoparticles (FeNPs) into fractal dendrite-like structures is reported. The fractal alignment was addressed by the diffusion-limited aggregation dynamics of solvent dewetting. Ethylene glycol and folate anion were used as capping agents of the FeNPs. The presence of ethylene glycol is critical for the fractal growth process. X-ray and magnetisation measurements, scanning and transmission electron microscopies, confocal fluorescence and Raman spectroscopies were used to characterise the dendritic structures.