Magnetoelectric (ME) CoFe2O4–Pb(Zr,Ti)O3 composite thin films have been prepared by a sol-gel process and spin-coating technique. X-ray diffraction and scanning electron microscopy reveal that there exists local aggregation or phase separation of the CoFe2O4 and Pb(Zr,Ti)O3 phases in the films. Vibrating sample magnetometer, ferroelectric test unit, and magnetoelectric measuring device were used to characterize the magnetic and ferroelectric properties, as well as the ME effect of the films. It is shown that the films exhibit both good magnetic and ferroelectric properties, as well as a ME effect. A high initial magnetoelectric voltage coefficient for the film is observed. The ME effect of the film strongly depends on the magnetic bias and magnetic field frequency.
The rapid expansion of electric vehicles and mobile electronic devices is the main driver for the improvement of advanced high-performance lithium-ion batteries (LIBs). The electrochemical performance of LIB depends on the specific capacity, rate performance and cycle stability of the electrode material. In terms of the enhancement of LIB performance, the improvement of anode material is also significant compared with cathode material. There are still some challenges in producing an industrial anode material that is superior to commercial graphite. Based on the different electrochemical reaction mechanisms of anode materials for LIBs during charge and discharge, the advantages/disadvantages and electrochemical reaction mechanisms of intercalation-type anode materials, conversion-type anode materials and alloying-type anode materials are summarized in detail. The methods and strategies for improving electrochemical performance of different types of anode materials are emphatically described. Finally, the challenges to the future development of LIBs will be considered. This review can offer meaningful reference value for the construction and performance optimization of anode materials for LIBs.
The relics of ancient rice have been regarded as the most important objective evidence of the origination and spread of rice cultivation. Based on the records of 280 rice relics sites and the rice cropping regionalization as well as the distribution map of paddy soils, the current study compiled the temporal and spatial distribution map of ancient rice distribution in China. The map shows that the distribution of ancient rice is spatially extensive and meantime comparatively concentrated, temporarily covering a long and relatively continuous time-span. The rice relics in the Central China double and single rice cropping regions are among the earliest and the most abundant ones, possessing continuity in time sequence. Combined with the discovery of ancient rice and paddy filed relics, soil micromorphology, pollen combination and element geochemistry, it is suggested that Central China was the origin center of rice cultivation in China. Rice had been spread to the rest part of China in three major waves, also to the East Asian part like Korea and Japan. The temporal and spatial distribution of ancient rice reflects the past environmental change, which is also meaningful to the current rice regionalization and planning as well as food security in China.
Magnetoelectric CoFe(2)O(4)-Pb(Zr,Ti)O(3) nanostructured films with various phase connectivity patterns were prepared by a pulsed laser deposition method. It was found that the microstructure as well as the phase connectivity pattern of the film varied remarkably with the variation of phase content ratio. All composite nanofilms exhibit evident ferromagnetic and ferroelectric characteristics, as well as distinct magnetoelectric coupling behavior upon increasing the magnetic field. The correlation between the phase connectivity pattern and magnetoelectric coupling behavior for the composite nanofilm was revealed. This work provides an efficient avenue to modulate the magnetoelectric coupling behavior for the ferroelectric-ferromagnetic composite nanofilm.
A simple method is reported for the preparation of double-helical structures through a series of achiral random and block copolymers poly(styrene-co-4-vinylbenzyl triazolylmethyl methylthymine) (PS-co-PVBT) with various T units on the side chains through click reactions of poly(styrene-co-4-vinylbenzyl azide) (PS-co-PVBN(3)) with propargyl thymine (PT) and also the synthesis of the A-appended pyrene derivative (A-Py) through click chemistry. This double-helical structure is observed from achiral random-coil polystyrene (PS) main chains, stabilized through the combination of multiple A-T hydrogen bonds, and π-π stacking between pyrene units and single-walled carbon nanotubes (SWCNTs).
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