Special rutile titanium dioxide (TiO₂) hollow microspheres were prepared successfully through hydrothermal methods when tetrabutyl titanate was adopted as raw material, β-cyclodextrin as template agent and polyvinylpyrrolidone as auxiliary agent. The effect of the concentration of hydrochloric acid and the temperature on the formation of TiO₂ morphology was discussed and the structure of the powders confirmed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscope. The colour of products changed from black to white after roasted, and the results of FT-IR and XRD measures showed its structure conforming to the rutile TiO₂. It was found that the TiO₂ powders were hollow microspheres, and its surface tightly wrapped by nanorods for uniform, smooth, and orientation rule, which was of larger specific surface area.

The analysis, simulation and experimental fabrication of three-dimensional (3D) cylindrical tubes formed from 2D aluminium/silicon dioxide (Al/SiO₂) substrates are presented. The photolithographically fabricated planar Al/SiO₂ substrates bend under residual mechanical stress after release, self-assembling into 3D cylindrical tubes. They present an analytical model that allows them to reliably predict the resulting radius of curvature of bi-layer Al/SiO₂ tubes with uniform cross-sections, and provides an approximate solution for SiO₂ substrates with patterned Al cross-sections. Finite element analysis simulations and measurements of fabricated tubes show agreement with the model. In addition, they show through a series of batch experiments that the self-assembly process is repeatable with proper design of the substrates.

Nano-manipulation is one of the most important aspects of nano-robotics and nano-assembly. The positioning process is considered by many researches to be one of the most important parts of nano-assembly, but has been poorly investigated, particularly for biologic samples. This Letter is devoted to modelling the process of positioning a biomolecule with atomic force microscopy (AFM) in an aqueous media using molecular dynamics simulations. Carbon nanotube (CNT) and graphite sheet are selected as AFM tip and substrate, respectively. To consider the effects of the medium on the manipulation, several models for decreasing the calculations including implicit, coarse grained, and all-atom methods have been investigated. They examined several parameters which may affect the quality of the manipulation process such as the CNT initial position with respect to the sample and substrate, its diameter and positioning strategies (pushing or pulling). The results demonstrate that despite of the implicit solvent methods, coarse-grained model can simulate the aqueous media accurately with lower computational cost. Furthermore, pulling method with a CNT which has a larger diameter and a smaller gap with respect to the substrate is the most appropriate setting for manipulation.

The effect of power tubes on AZ91D magnesium (Mg) alloy was investigated by high-speed wire electrical discharge machine (WEDM-HS). This Letter presented the different surface characteristics and corrosion resistance of the fabricated surface. Chemical composition of the fabricated surface was analysed by energy-dispersive X-ray spectroscopy, and the surface salt water contact angle was also measured in this study. The machined surface evidenced a carbon layer and high hydrophobic property (contact angle between 146° and 150°). The corrosion resistance of the samples machined by the WEDM-HS process was studied in 3.5% NaCl solution through electrochemical impedance spectroscopy. The results have shown that when electrical parameters of the five power tubes were used, the good surface properties of the fabricated surface were obtained with few micropits, and using the higher power tube was helpful to improve the AZ91D corrosion resistance. A handy WEDM-HS technology for treating AZ91D is a useful way to improve the corrosion resistance of the AZ91D Mg alloy.

A surface modification method has been developed to fabricate surface plasmon resonance (SPR) chip for small molecule determination. A novel denaturalised bovine serum albumin (dBSA)-SPR-chip was fabricated by a self-assembling method, while a dextran-SPR-chip was prepared by using a traditional method. The surface morphologies of the two chips were investigated by atomic force microscopy technology and their optical properties were characterised by using our home-made SPR analytical instrument. The surface binding capacity of the dBSA-SPR-chip is 2.5 times higher than that of the dextran-SPR-chip. On the basis of the experiments of immune reactions between cortisol antibody and cortisol derivative, the sensitivity of the dBSA-SPR-chip is much higher than that of the dextran-SPR-based SPR-chip. The antibody concentration was optimised at about 10 µg/ml in order to obtain high sensitivity, which was used in the followed inhibition immunoassays. The lowest detection limit for cortisol is 1 ng/ml with a linear range of 5–100 ng/ml by using the dBSA-SPR-chip. These dBSA-SPR-chips can also be applied to detect other small molecules based on the indirect inhibitive immunoassay.

To improve the safety of octahdro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), a submicron energetic material, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), was introduced to coat HMX by a novel method. This novel method contained the reaction crystallisation and the solvent–non-solvent method. X-ray diffraction, scanning electron microscope, and optical microscopy analyses showed that a homogeneous layer of TATB particles with submicron scale had been successfully coated on the surface of HMX particle. Differential scanning calorimetry and thermogravimetry indicated that the coated HMX only had an exothermic peak at 279.4 °C, and the phase transition temperature reached 213.5 °C and increased by 20.2 °C compared with the pure HMX. The content of the coating TATB was determined to be 6.2 wt.% through high-performance liquid chromatograph. Relative to the mechanically mixed HMX/TATB, the drop height (H ₅₀) was increased from 23.0 to 74.1 cm, and the friction probability was reduced from 4 to 0% for the coated HMX.

The fracture of movable part is a serious issue in micro-electro-mechanical systems (MEMS) device application. However, its fracture mechanism is not clear yet. The fracture mechanism of movable part based on empirical electron theory (EET) of solids and molecules, in which fracture model is built based on valence electron structure and broken bond of the crystal plane is clarified. Simulation and test results match EET-fracture model quite well with low errors of 8.22 and 5.95%, respectively, which shows a good accuracy among existing fracture models. It is believed that EET-fracture model is quite effective and useful to evaluate movable part function in the research of MEMS devices.

Here, an MeV proton beam irradiation-induced nano-welding technique to fabricate X-, Y-, II- and T-shapes molecular junctions between silver nanowires using high proton beam current is demonstrated. Transmission electron microscopy, scanning electron microscopy and X-ray diffraction revealed that nano-welding of Ag-NWs is successfully achieved with stable crystal structure. Nano-welding process and corresponding large-scale fabrication of networks are discussed.

The design of a multi-input–multi-output (MIMO) model predictive control (MPC) framework for reducing errors in images scanned by an atomic force microscope (AFM) is presented. To improve the damping capability of the proposed control framework, it is augmented with a damping compensator. The MIMO form of this control framework compensates the tilted natures of the scanned images by compensating the cross-coupling effect while its augmented damping compensator reduces the vibration effect by improving damping in the resonant mode of the AFM's piezoelectric tube scanner. Experimental results using the existing AFM proportional–integral controller and single-input–single-output MPC are also presented to show the effectiveness of the MIMO MPC controller. This Letter is an extension of an authors’ earlier published work.

A rapid method to fabricate a flow-focusing microfluidic device with circular channels for droplet generation is presented. To create the desired ‘polydimethylsiloxane (PDMS)’ channel geometry, moulds using a rapid and cheap three dimensional (3D) printing process comparing with conventional microfabrication method have been fabricated. The 3D printer with a 16 μm layer resolution utilised to fabricate 100 μm half circular microfluidic moulds. The finished moulds were baked and silanized prior to casting to avoid the incomplete curing problem of the ‘PDMS’ castings. Casted ‘PDMS’ halves were aligned and bonded together to build complete microfluidic chips by an oxygen plasma treatment. Due to the resolution limitation of 3D printing, the channels were not perfectly circular rather than elliptical. A liquid ‘PDMS’ injection process was used and optimised to create fully circular channels, and also address challenges regarding the misalignment of the upper and lower halves of the microfluidic chip. Circular channels were successfully formed in the flow-focusing microfluidic device through the post ‘PDMS’ injection process without any blockage of the cross junction. The device functioned well to create ∼200 μm droplets.

Superhydrophobic surface on aluminium (Al) substrate was successfully fabricated via a microwave-assisted process by immersing the clean pure Al substrate into the mixed solution of Zn(NO₃)₂ and hexamethylenetetramine, and modified with stearic acid (STA). Surface morphology and composition were characterised by using scanning electron microscopy (SEM), X-ray diffraction and X-ray photoelectron spectroscopy. The wettability and the corrosion resistance properties of the surface modified with STA were characterised. The results show that the sample had a high water contact angle of about 155°. It has good anti-corrosion for alkali and 3.5 wt% sodium chloride solution. From SEM images, it was found that abundant regular micronano sheets distributed on the surface at random and there are large amount of interspace amount the sheets. The special structure and the low surface energy make the Al foil have superhydrophobic surfaces.

Titania (TiO₂) coated polystyrene (PS) (PS/TiO₂ core-shell) colloids were prepared by sol–gel process and self-assembled into photonic crystals through the vertical deposition method. The PS/TiO₂ core-shell colloidal particles were characterised using SEM, laser particle size analyser, FTIR and EDS. The results show that the colour is shifted gradually from blue to red with the increase of titania shell thickness which changes both the particle size and the contrast index.

SnO₂/CNT (CNT: carbon nanotube) composite electrode materials have been successfully synthesised using the Pechini method. The crystal structures of SnO₂/CNTs were identified by X-ray diffraction. The surface morphology and internal structure, as revealed by scanning electron microscopy and transmission electron microscopy, indicated that SnO₂ nanoparticles were embedded in the CNT matrix or dispersed homogeneously on the outer walls of the CNTs. Furthermore, the charge–discharge properties of SnO₂/CNT composite electrode materials showed that the reversible discharge capacities of the SnO₂/CNT composite electrode materials were enhanced to 1062 mAh/g compared with that of pure SnO₂ nanoparticles, and the capacity retention remained at approximately 91% after the 12th cycle, improving the lifetime of the lithium batteries greatly.

Wire-like and flower-like cerium ion (Ce³⁺)-doped neodymium phosphate nanostructures (NdPO₄:Ce³⁺ NSs) were synthesised via a direct precipitation process at room temperature. The different reaction conditions such as the phosphate anion source, solvent, and surfactant were carried out to discuss the influence for the morphologies and photoluminescence (PL) properties. Experimental results showed that the surfactants of dodecyl benzene sulphonic acid sodium and dodecyl sulphonic acid sodium play an important role in controlling the flower-like NdPO₄:Ce³⁺ NSs. The flower-like NdPO₄:Ce³⁺NSs exhibited higher PL property than that of wire-like NdPO₄:Ce³⁺NSs.

In the fabrication of crystalline silicon-based solar cells, silicon surface is usually texturised by wet anisotropic etchant without using any masking pattern. This method provides randomly oriented upright pyramids (or hillocks) of varying sizes. However, a surface textured with inverted pyramids yields high efficiency compared with the one textured with normal pyramids. Silicon dioxide thin films synthesised using anodic oxidation technique at room temperature are explored as etch mask in KOH solutions to texturise the Si{100} surface with inverted pyramids without patterning of the oxide layer using lithography. Oxide films of ∼50 nm thickness are synthesised in different compositions of the electrolyte under potentiodynamic regime. Thickness uniformity and refractive index of the as-grown oxide films are measured using spectroscopic ellipsometry. Scanning electron microscope is primarily used to inspect the etched surface morphology. The composition of the electrolyte, KOH concentration and etching time are optimised for the maximum surface coverage of inverted pyramids. The surface texturing process demonstrated is very simple and economic as it utilises anodic silicon dioxide as an etch mask, which is deposited by a simple experimental setup and the process does not involve any lithography step.