Is f1(1420)f_1(1420) the partner of f1(1285)f_1(1285) in the 3P1^3P_1 qqˉq\bar{q} nonet?

Based on a $2\times 2$ mass matrix, the mixing angle of the axial vector states $f_1(1420)$ and $f_1(1285)$ is determined to be $51.5^{\circ}$, and the theoretical results about the decay and production of the two states are presented. The theoretical results are in good agreement with the present experimental results, which suggests that $f_1(1420)$ can be assigned as the partner of $f_1(1285)$ in the $^3P_1$ $q\bar{q}$ nonet. We also suggest that the existence of $f_1(1510)$ needs further experimental confirmation.Comment: Latex, 6 pages, to be published in Chin. Phys. let

ZnO-doped LiFePO4 cathode material for lithium-ion battery fabricated by hydrothermal method

LiFePO4 particles doped with zinc oxide was synthesized via a hydrothermal route and used as cathode material for lithium-ion battery. Sample of preferable shape and structure was obtained by a concise and efficient process. ZnO doping into the LiFePO4 matrix was positively confirmed by the results of X-ray diffraction (XRD); high-resolution transmission electron microscopy (HRTEM); energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). LiFePO4 doped with ZnO tends to form nanometer-size and homogeneous particles, which can improve markedly the performance and stability of charge-discharge cycle. A specific discharge capacity of ZnO-doped LiFePO4 at 132.3 mAh g-1 was achieved, with 1.8% decrease after 100 cycles. Based on the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results, it has further shown that ZnO doping effectively reduces the impacts of polarization and transfer resistance during electrochemical processes

Nanoengineering to achieve high sodium storage: A case study of carbon coated hierarchical nanoporous TiO2 microfibers

Nanoengineering of electrode materials can directly facilitate sodium ion accessibility and transport, thus enhancing electrochemical performance in sodium ion batteries. Here, highly sodium-accessible carbon coated nanoporous TiO2 microfibers have been synthesised via the facile electrospinning technique which can deliver an enhanced capacity of ≈167 mAh g−1 after 450 cycles at current density of 50 mA g−1 and retain a capacity of ≈71 mAh g−1 at the high current rate of 1 A g−1. With the benefits of their porous structure, thin TiO2 inner walls, and the introduction of conductive carbon, the nanoporous TiO2/C microfibers exhibit high ion accessibility, fast Na ion transport, and fast electron transport, thereby leading to the excellent Na-storage properties presented here. Nanostructuring is proven to be a fruitful strategy that can alleviate the reliance on materials\u27 intrinsic nature; and the electrospinning technique is versatile and cost-effective for the fabrication of such an effective nanoporous microfiber structure

Progress of HDDR NdFeB powders modulated by the diffusion of low melting point elements and their alloys

The hydrogenation-disproportionation-desorption-recombination (HDDR) process is the main technique for the fabrication of anisotropic NdFeB magnetic powder.But the intrinsic coercivity (HC) of HDDR magnetic powder is low.The addition of heavy rare earth element Dy could improve its HC.It was found that the added Dy is mainly distributed in the grain boundary of HDDR magnets,which regulates grain boundary phase and increases the thickness of grain boundary to improve the anisotropy field (HA) and HC of the magnets.However,Dy becomes scarcer and more expensive,which limits the practical application of HDDR magnets.To reduce the dependence on heavy rare earth elements and cost,researchers replaced the heavy rare earth element Dy by low melting point elements and their alloys through grain boundary diffusion technique.During diffusion process low melting point metal exists as liquid phase that increases the diffusion coefficient of diffusion medium as well as its contact area with grain boundary phases of HDDR magnets,and benefits its diffusion along grain boundaries and regulation of grain boundary phase.The modified grain boundary in magnets improve HC.This review paper focuses on the research progress in improving HC of HDDR NdFeB magnets by low melting point elements and their alloys

Effective Electrochemiluminescence Aptasensor for Detection of Atrazine Residue

According to the chemiluminescence characteristics of the luminol-hydrogen peroxide (H2O2) system, this work designed a novel and effective electrochemiluminescence (ECL) aptasensor to detect atrazine (ATZ) rapidly. Silver nanoparticles (AgNPs) could effectively catalyze the decomposition of H2O2 and enhance the ECL intensity of the luminol-H2O2 system. Once ATZ was modified on the aptasensor, the ECL intensity was significantly weakened because of the specific combination between ATZ and its aptamer. Therefore, the changes in ECL intensity could be used to detect the concentration of ATZ. Under optimal detecting conditions, the aptasensor had a wide linear range from 1 × 10−3 ng/mL to 1 × 103 ng/mL and a low limit of detection (3.3 × 10−4 ng/mL). The designed aptasensor had the advantages of good stability, reproducibility, and specificity. The aptasensor could be used to detect the ATZ content of tap water, soil, and cabbage and had satisfactory results. This work effectively constructs a novel, effective, and rapid ECL aptasensor for detecting ATZ in actual samples

Sn/SnO2@C composite nanofibers as advanced anode for lithium-ion batteries

Sn/SnO2@C composite nanofibers were successfully fabricated by a facile annealing strategy. The composite consists of an amorphous carbon matrix encapsulating carbon nanotubes decorated by ultrafine (\u3c10 \u3enm) SnO2 nanoparticles, with submicron Sn particles incorporated in the entangled networks of the composite nanofibers. When used as anode material for lithium ion batteries, the Sn/SnO2@C composite nanofibers exhibited high initial charge capacity of 756 mAh g-1 at 100 mA g-1, excellent high-rate capacity of 190 mAh g-1 at 5 A g-1, and excellent capacity retention of 591 mAh g-1 after 100 cycles at 100 mA g-1. High-resolution transmission electron microscopy, energy dispersive spectroscopy mapping, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy were applied to investigate the origins of the excellent electrochemical Li+ storage properties of Sn/SnO2@C. It could be deduced that the ductile carbon matrix and free spaces in the composite nanofiber networks can effectively accommodate the strain of volume change during cycling, prevent the aggregation and pulverization of Sn/SnO2 particles, keep the whole structure stable, and facilitate electron and ion transport through the electrode

A facile synthesis of core-shell structured ZnO@C nanosphere and their high performance for lithium ion battery anode

A core-shell structured design of ZnO@C nanosphere with uniform particle size of 200 nm has been successfully synthesized by a facile route - extended Stöber method. The well designed ZnO@C nanosphere shows a typical core-shell structure with a ~ 160 nm core and ~20 nm carbon shell which could improve their stability and performance as electrodes for lithium ion batteries (LIBs). When used as anode materials for LIBs, the core-shell structured ZnO@C nanospheres give a reversible capacity of 496 mA h g-1 after 200 cycles at a current density of 82.5 mA g-1. The amazing enhanced electrical performance can be contributed to the core-shell structured, which prevents the pulverization of anode during charge/discharge process

Progress of sintered NdFeB permanent magnets by the diffusion of non-rare earth elements and their alloy compounds

It has been found that the coercivity (HC) and corrosivity of sintered NdFeB magnets are closely related to the components and microstructure of their intergranular phase.The traditional smelting NdFeB magnets with adding heavy rare earth elements can modify intergranular phase to improve the HC and corrosion resistance of magnets.However,it makes the additives be homogenously distributed on the main phase,and causes magnetic decrease and cost increase.With the addition of non-rare earth materials into grain boundary,the microstructure of intergranular phase as well as its electrochemical potential and wettability can be optimized.As a result,the amount of heavy rare earth elements and cost of magnets could be reduced whilst the HC and corrosion resistance of magnets can be improved.This paper summarized the research on regulating the components and the microstructure of intergranular phase in sintered NdFeB magnets by non-rare earth metals and compounds,and its influence on coercivity and corrosion resistance

Fluorescence Assay for Detecting Four Organophosphorus Pesticides Using Fluorescently Labeled Aptamer

In this work, we reported a rapid and sensitive fluorescence assay in homogenous solution for detecting organophosphorus pesticides by using tetramethylrhodamine (TAMRA)-labeled aptamer and its complementary DNA (cDNA) with extended guanine (G) bases. The hybridization of cDNA and aptamer drew TAMRA close to repeated G bases, then the fluorescence of TAMRA was quenched by G bases due to the photoinduced electron transfer (PET). Upon introducing the pesticide target, the aptamer bound to pesticide instead of cDNA because of the competition between pesticide and cDNA. Thus, the TAMRA departed from G bases, resulting in fluorescence recovery of TAMRA. Under optimal conditions, the limits of detection for phorate, profenofos, isocarbophos, and omethoate were 0.333, 0.167, 0.267, and 0.333 µg/L, respectively. The method was also used in the analysis of profenofos in vegetables. Our fluorescence design was simple, rapid, and highly sensitive, which provided a means for monitoring the safety of agricultural products

Ship Recognition from Chaff Clouds with Sophisticated Polarimetric Decomposition

Ship recognition from chaff cloud jamming is challenging since they have similar dimensions and radar cross sections. In this paper, a polarimetric recognition technique with sophisticated polarimetric decomposition is proposed. To this end, a seven-component model-based decomposition is first put forward by integrating three sophisticated scattering models, thus the dominant and local scattering of ships can be characterized accurately. According to the derived scattering contributions, a robust discrimination feature is then designed based on the concept of contrast and suppression. Coupled with the average scattering angle estimated from eigen-based decomposition, the constructed feature vector is inputted into the support vector machine and the recognition is finally fulfilled. The proposed method is tested on simulated and real polarimetric radar data and the results demonstrate that the proposed method achieves the highest recognition rate of over 98%, which outperforms the state-of-the-art methods