Time filter

Source Type

Tianjin, China

Tianjin Normal University is a university in Tianjin, China. Wikipedia.

Silicon.carbon.nitrogen material (SiCN) is pyrolyzed from polysilylethylenediamine (PSEDA) derivation, followed by a heat-treating process at 1000°C in Ar atmosphere. This heat-treated SiCN material has an excellent electrochemical performance as an anode for lithium ion batteries. Charge.discharge cycle measurements show that the heat-treated SiCN material exhibits a high first cycle discharge capacity of 829.0mAhg-1 and stays between 400 and 370mAhg-1 after 30 cycles. The discharge capacity remains above 300mAhg-1 at the high current density of 80 and 160mAg-1. These values are higher than untreated SiCN and commercial graphite anodes, which indicates that the heat-treating process improves the charge.discharge capacity, cycle stability and high-rate ability of SiCN anode. It is seemed that changes of SiCN structure, the formation of loose nano-holes on material surface and the formation of graphitic carbon phase in heat-treating process contribute to the improvement of electrochemical properties for SiCN anode. © 2010 Elsevier Ltd. All rights reserved. Source

Zhou L.,Tianjin Normal University
Nonlinear Dynamics

Proportional delay, which is different from distributed delay, is a kind of unbounded delay. The proportional delay system as an important mathematical model often rises in some fields such as physics, biology systems, and control theory. In this paper, the uniqueness and the global asymptotic stability of equilibrium point of cellular neural networks with proportional delays are analyzed. By using matrix theory and constructing suitable Lyapunov functional, delay-dependent and delay-independent sufficient conditions are obtained for the global asymptotic stability of cellular neural networks with proportional delays. These results extend previous works on these issues for the delayed cellular neural networks. Two numerical examples and their simulation are given to illustrate the effectiveness of obtained results. © 2014 Springer Science+Business Media Dordrecht. Source

Zhou L.,Tianjin Normal University
Nonlinear Dynamics

In this paper, the problem of dissipativity is investigated for cellular neural networks with proportional delays. Without assuming monotonicity, differentiability, and boundedness of activation functions, two new delay-independent criteria for checking the dissipativity of the addressed neural networks are established by using inner product properties and matrix theory. Two examples and their simulation results are given to show the effectiveness and less conservatism of the proposed criteria. © 2013 Springer Science+Business Media Dordrecht. Source

Zhao D.,Tianjin Normal University
PloS one

The ratio of the length of the second finger to the fourth finger (2D:4D) in humans is considered as a putative marker of prenatal exposure to testosterone, and has been progressively adopted as one useful tool to evaluate the effect of prenatal hormones in some traits such as physical ability. Handgrip strength is one authentic measure of physical ability and is generally used on the anthropological research within an evolutionary viewpoint. Here we present the first evidence on 2D:4D and handgrip strength on adult participants of Hani ethnicity and explore the relationship between digit ratio (2D:4D) and handgrip strength. We examined 2D:4D and handgrip strength of 80 males and 60 females at Bubeng village, in the Yunnan province of China. The mean 2D:4D in females was higher than that in males for each hand. Females showed significantly higher 2D:4D than males in the right hand rather than in the left hand. Males displayed significantly higher handgrip strength than females for both hands. Handgrip strength decreased with age for both sexes. A significant negative correlation between 2D:4D and handgrip strength was found in the right hand of males. The relationship between 2D:4D and handgrip strength may be attributed to evolutionary drive of sexual selection operating on fetal programming. Source

LiFePO4-MWCNTs (multi-walled carbon nanotubes) composite cathode materials were prepared by mixing LiFePO4 and MWCNTs in ethanol followed by heat-treatment at 500 °C for 5 h. The structural, morphology and electrochemical performances of LiFePO4-MWCNTs composite materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge-discharge cycle tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicated that MWCNTs adding improved the electronic conductivity, the discharge capacity, cycle stability and lithium ion diffusion kinetics of LiFePO4, but MWCNTs adding did not charge the orthorhombic olivine-type structure of LiFePO4. In all these prepared LiFePO4 with x wt.% MWCNTs (x = 4, 7, 10) composites, 7 wt.% MWCNTs adding composite cathode shows the best electrochemical performance, which gets an initial discharge capacity of 152.7 mAh g-1 at 0.18 C discharge rates with capacity retention ratio of 97.77% after 100 cycles. © 2010 Elsevier B.V. All rights reserved. Source

Discover hidden collaborations