[en] Highlights: • The fabricated pebbles can be densified (81% T.D.) at a low sintering temperature (850 °C). • The pebbles’ size can be controlled during the fabrication process. • Average grain size of the Li_2TiO_3 pebbles is less than 1 μm (0.82 μm). • The molar ratio of Li to Ti of the pebbles sintered at 850 °C keeps the value of 1.97 after sintering. - Abstract: Lithium titanate (Li_2TiO_3) ceramic pebbles were successfully fabricated by using hydrothermal and improved dry-rolling method. In the present work, ultra-fine Li_2TiO_3 powder of high reactivity was prepared via hydrothermal reaction, using anatase titania and lithium hydroxide as raw materials. The as-synthesized Li_2TiO_3 powder exhibits an average crystalline size as small as 100 nm. Improved dry-rolling method was employed to fabricate Li_2TiO_3 pebbles. The green pebbles can be well-sintered (81% T.D.) at a temperature as low as 850 °C for 3 h. The pebbles have good sphericity (1.08) and narrow diameter distribution (1.0–1.2 mm) with a crush load of 35 N. Scanning electron microscope (SEM) observations of pebbles showed that the ceramic grain size was below 1 μm and atomic emission spectrometer fitted with inductively coupled plasma (ICP-AES) results confirmed that atomic ratio of Li to Ti in the fabricated pebbles was 1.97

[en] Graphene oxide (GO)/poly(2-methylaniline) (P2MAN) composite particles were prepared by chemical oxidation polymerization and adopted as an electrorheological (ER) material. Because of its electrical conductivity originating from both semi-conducting P2MAN and GO, it could be tuned finely using P2MAN for ER applications. The morphology and chemical structure of the composite were examined by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The ER properties of the GO/P2MAN composite particles dispersed in silicone oil were examined with and without an applied electric field. The fibrillation phenomenon of this GO/P2MAN-based electro-responsive fluid was also observed by optical microscopy under an electric field. The flow curves and dynamic modulus of the GO/P2MAN suspension were measured by rotational rheometry under a range of electric field strengths, exhibiting typical ER characteristics and a slope of the dynamic yield stress of 1.5. GO appeared to improve the compatibility of the composite particles within the medium, which resulted in improved sedimentation stability compared to that of the P2MAN-based ER fluid. - Highlights: • GO/P2MAN composite was fabricated by Hummers method and oxidation polymerization. • The composite particles based fluid exhibited typical electrorheological properties. • The fluid was correlated to conduction model and showed solid-like characters. • GO was helpful to improve stability of fluid due to large surface area and compatibility

[en] Graphical abstract: - Highlights: • GO-based PANI, NCOPA and PS nanocomposites are prepared. • The nanocomposites are adopted as novel electrorheological (ER) candidates. • Their critical ER characteristics and dielectric performance are analyzed. • Typical ER behavior widens applications of GO-based nanocomposites. - Abstract: Graphene oxide (GO), a novel one-atom carbon system, has become one of the most interesting materials recently due to its unique physical and chemical properties in addition to graphene. This article briefly reviews a recent progress of the fabrication of GO-based polyaniline, ionic N-substituted copolyaniline and polystyrene nanocomposites. The critical electrorheological characteristics such as flow response and yield stress from rheological measurement, relaxation time and achievable polarizability from dielectric analysis are also analyzed

[en] Highlights: • A novel piezoelectric energy harvester driven by magnetic force is proposed. • A multi-step mechanism and a bistable structure are designed for the harvester. • The harvester has a wide working bandwidth and a stable high-voltage output. • The magnet array with staggered magnetic poles can increase the output voltage. - Abstract: In this paper, a multi-step buckled beam piezoelectric energy harvester driven by magnetic force is proposed. To convert ambient mechanical vibration into electrical energy with increased operational frequency bandwidth and power density, the harvester utilizes a combination of multi-step mechanism and bistable structure. A multi-step mechanism in the form of a magnet array with staggered magnetic poles has been designed for the energy harvesting system to obtain a wide working bandwidth. A buckled beam as a bistable structure enables the harvester to demonstrate a high-voltage output. A theoretical model is developed to characterize the multi-step piezoelectric energy harvester. Both simulations and experiments on the fabricated experimental device are carried out to validate the design and analysis of the multi-step piezoelectric energy harvester. The experimental results indicate that output open circuit voltage of the harvester is 4.4 V. The harvester generates a peak power of 5.0 μW across resistive load of 3.3 MΩ at the frequency of 3.0 Hz. The results show that the device can cause stable output voltage under wideband excitations. Furthermore, under the multi-step mechanism, the magnet array with staggered magnetic poles increases the output voltage of the harvester by 25.0% compared to the unidirectional magnetic pole arrangement.

[en] Sonoluminescence is a complex phenomenon, the mechanism of which remains unclear. The present study reveals that an abnormal ionization process is likely to be present in the sonoluminescing bubble. To fit the experimental data of previous studies, we assume that the ionization energies of the molecules and atoms in the bubble decrease as the gas density increases and that the decrease of the ionization energy reaches about 60%–70% as the bubble flashes, which is difficult to explain by using previous models. (paper)

No abstract available

[en] Graphical abstract: -- Highlights: •A new coupling of thin-layer electrolysis with capillary electrophoresis (CE). •Rapid electrolysis, direct sampling followed by online CE separation. •At least 13 products of quercetin oxidation were separated. •Thermodynamic and kinetic parameters were determined from CE peak areas. -- Abstract: A coupling technique of thin-layer electrolysis with high-performance capillary electrophoresis/UV–vis technique(EC/HPCE/UV–vis) is developed for online separation and determination of electrode reaction products. A chip-type thin-layer electrolytic (CTE) cell was designed and fabricated, which contains a capillary channel and a background electrolyte reservoir, allowing rapid electrolysis, direct sampling and online electrophoretic separation. This chip-type setup was characterized based on an electrophoresis expression of Nernst equation that was applied to the redox equilibrium of o-tolidine at different potentials. The utility of the method was demonstrated by separating and determining the electro-oxidation products of quercetin in different pH media. Two main products were always found in the studied time, potential and pH ranges. The variety of products increased not only with increasing potential but also with increasing pH value, and in total, at least 13 products were observed in the electropherograms. This work illustrates a novel example of capillary electrophoresis used online with thin-layer electrolysis to separate and detect electrode reaction products

No abstract available

[en] Objective: To discuss the clinical value of CT angiography (CTA) in diagnosis of myocardial bridge and mural coronary artery. Methods: Three hundred twenty-seven patients were performed 64 slices CT angiography to observe myocardial bridge, and evaluate the stenosis of mural coronary artery.All cases with myocardial bridge received coronary arteriongraphy and comparison. Results: Fifty-seven cases with 66 myocardial bridge segments were found, with mean length (4.72 ± 0.93) mm, mean thickness (2.04 ± 0.62) mm, the mean stenosis of mural coronary artery was (33 ± 20)%. Twenty-nine cases with 35 myocardial bridge segments were found by coronary arteriongraphy, the difference between them has statistical significance (P<0.05). Conclusion: CTA can clearly show myocardial bridge and mural coronary artery, and it has important significance in clinical diagnosis compared with traditional coronary arteriongraphy. (authors)

[en] Some source modifications and tests before and after installing the source to SFC beam line are reported. A preliminary study on an electron gun with cold cathode used in CAPRICE type ECR source is presented