Synthesis of Titanium Carbide Nanoparticles with a High Specific Surface Area from a TiO2 Core–Sucrose Shell Precursor

By carbothermally reducing a TiO₂ core–sucrose shell precursor, titanium carbide mesoporous nanoparticles with a very high specific surface area (147 m²/g at 1500°C) have been prepared. The high specific surface area results from the mesoporous nature of the produced nanoparticles with two types of pores: the one with a pore diameter of about 20 nm and the other with <4 nm.     

Functionalization of fullerene nanowhiskers using pyrenebutanoic acid, succinimidyl ester in an aqueous solution

The functionalization of fullerene nanowhiskers was accomplished by non-covalent π-π interaction using pyrenebutanoic acid, succinimidyl ester to immobilize target molecules on the nanowhiskers. Fourier-transform infrared spectroscopy and fluorescence microscopy proved that the fullerene nanowhiskers were functionalized without damaging the nanostructure.     

Electrochemical behavior of carbon-coated SnS2 for use as the anode in lithium-ion batteries

Carbon-coated SnS₂ nanoparticles were prepared by a simple solvothermal route at low temperature. A carbon coating with a thickness of about 5 nm was deposited on nano-sized SnS₂ particles to serve as the anode in lithium-ion batteries. Both the nanostructure and the morphology of the SnS₂ powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The coated samples were used as active anode materials for lithium-ion batteries, and their electrochemical properties were examined by constant current charge-discharge cycling, cyclic voltammetry and electrochemical impedance spectroscopy. The reversible capacity of the carbon-coated SnS₂ after 50 cycles was 668 mAh/g, which was much higher than that of the uncoated SnS₂ (293 mAh/g). The carbon-coated SnS₂ also had a better rate capability than the uncoated SnS₂ in the range of 0.008-1 C. The capacity retention of the carbon-coated SnS₂ was improved due to its good conductivity and the effective buffer matrix that alleviated volume expansion during the charge-discharge process.     

Fabrication of hollow silica particles using copolymeric spheres prepared in supercritical carbon dioxide

Amine functional polymeric spheres were prepared via the dispersion polymerization of 2-dimethylaminoethyl methacrylate and methylmethacrylate in supercritical carbon dioxide, and they were employed efficiently as templates for the fabrication of hollow silica particles. A small amount of divinyl benzene was used as a crosslinking agent to control the morphology of the copolymeric particles from clumpy solid to spherical shape. The assembly of the polymeric spheres with tetraethylorthosilicate (TEOS) through hydrothermal methods produced core-shell type hybrid particles. The whole process required neither surface treatment for the polymeric particles nor addition of any acidic or basic catalyst for the hydrolysis of silica precursor because dimethylamino groups of the copolymeric spheres were able to absorb water and catalyze the hydrolysis of TEOS for the deposition of the silica gel network. The polymeric cores were completely removed by calcination process and silica hollow particles with well-defined structure were obtained finally. The silica hollow particles were characterized by scanning electron microscopy and transmission electron microscopy, which clearly revealed that the silica spheres had the hollow structure with 151 nm wall thickness.     

Performance evaluation of an MR damper in building structures considering soil–structure interaction effects

Since the force generated by a magneto‐rheological (MR) damper has large nonlinearity, the performance of an MR damper is dependent on response characteristics such as frequency and amplitude. Soil–structure interaction (SSI) is generally known to have a large effect on the seismic response of a building structure. In this study, the performance of an MR damper in mitigating the seismic response of a building structure is evaluated considering the SSI effects. First, the performance variance of an MR damper due to the change of the structural natural period is investigated by constructing its normalized response spectrum through the numerical analysis of many earthquake wave records and the natural period of a structure. The variable friction force of an MR damper is normalized by the structural base shear force, and its amplitude and decrement of response are quantitatively evaluated. Then, the response characteristics of the SSI system due to the lengthening of the structural natural period and various soil conditions are numerically evaluated based on the response spectrum analysis. Finally, the numerical results with and without considering the SSI effects are comparatively evaluated for the building structure with an MR damper. The comparison results show that the SSI effect should be considered in order that the undesirable effect of an MR damper on the structural control would not be neglected. Copyright © 2007 John Wiley & Sons, Ltd.     

Reconfigurable microstrip antenna with polarisation diversity

A single probe-fed reconfigurable microstrip patch antenna with symmetric cross slots is proposed. By controlling four pin diodes on the patch slots, the proposed antenna has right hand circular polarisation, left hand circular polarisation or linear polarisation.     

Shorted Microstrip Patch Antenna Using Inductively Coupled Feed for UHF RFID Tag

A very small patch‐type RFID tag antenna (UHF band) using ceramic material mountable on metallic surfaces is presented. The size of the proposed tag is 25 mm×25 mm×3 mm. The impedance of the antenna can be easily matched to the tag chip impedance by adjusting the size of the shorting plate of the patch and the size of the feeding loop. The measured maximum reading distance of the tag at 910 MHz was 5 m when it was mounted on a 400 mm × 400 mm metallic surface. The proposed design is verified by simulation and measurements which show good agreement.     

Stability of isoflavone daidzein and genistein in riboflavin, chlorophyll b, or methylene blue photosensitization

ABSTRACT:  Effects of photosensitizers including riboflavin, chlorophyll b , or methylene blue on the stability of daidzein and genistein were studied in model systems by high-performance liquid chromatography (HPLC). Concentration of daidzein and genistein in 80% methanol with riboflavin under light for 7 h was significantly decreased with the apparent 1st-order rate constants of 0.234 and 0.193/h, respectively, ( P < 0.05), while those without riboflavin under light did not change significantly ( P > 0.05). The stability of isoflavone aglycones in the dark did not change significantly irrespective of the presence of riboflavin ( P > 0.05). The concentrations of daidzein and genistein in chlorophyll b or methylene blue model systems under light were not significantly different from those in the dark for 7 h ( P > 0.05). Addition of sodium azide increased the stability of daidzein and genistein in riboflavin photosensitization with concentration dependent manner. However, the protective effects of β-carotene addition on the photodegradation of isoflavones were not high. The stability difference of daidzein and genistein in riboflavin photosensitization may be due to the high reactivity of riboflavin through type I pathway, although singlet oxygen may be involved in part.     

Memristive Devices Based on Two-Dimensional Transition Metal Chalcogenides for Neuromorphic Computing

Two-dimensional(2D)transition metal chalcogenides(TMC)and their heterostructures are appealing as building blocks in a wide range of electronic and optoelectron...