Effects of controlled-release urea application on the growth, yield and nitrogen recovery efficiency of cotton

Field experiments were conducted to study the effects of the controlled release urea (CRU) application on growth yield and nitrogen recovery efficiency of cotton in the main cotton zone of the Yangtze River basin in 2010. Different nitrogen levels were set in order to determine the suitable dosage of CRU on cotton. The special purpose was to provide evidence for the CRU application in cotton fields. The results show that the application of CRU promotes the growth of cotton significantly and enhances the nitrogen supply in the whole period. Compared to the treatment with total N as base fertilizer (UB), the bod, flower, little bolls and total bolls are increased significantly. There are no significant differences in the yield between the CRU treatment and the treatment of controlled release urea and urea combined application (60%CRU + 40%U), but an increase by 12.38%-22.67% compared to the UB treatment, and an increase by 4.49%-7.23% compared to the treatments of total N split application (UD). The nitrogen uptake of CRU treatment was significantly increased by 13.01%-48.32% and 30.27%-13.01% than UB treatment and UD treatment, respectively. The nutrient recovery efficiency of CRU treatment is increased by 16.42-20.59, 5.92-11.29 and 4.22-12.59 percentage points compared to the UB treatment, UD treatment and 60%CRU + 40%U treatment, respectively. In this study, there was a good linearity relationship between the cotton yield and amount of CRU in Wuxue site. The yield of cotton response to amount of CRU could be described by the model of linear plus plateau in Jingzhou site.

Reflection on College Education and Teaching Management under New Media

Under the background of current social development,the role of media in the process of information dissemination is becoming more and more enlarged,the speed of information dissemination is greatly accelerated based on the platform built by the media.In the process of information dissemination,the related concepts of new media are derived based on the media platform.This is also the result of the continuous integration of information technology and network technology.Compared with the traditional media,the advantages of new media technology itself are more obvious both the source of information,but also the reporter and audience,so in the context of the development of new media art,the spread of various social hot issues is very fast,and the coverage is also wider.Under the background of the development of new media,colleges and universities themselves are greatly impacted by the information of new media,because people have higher acceptance of new media,so they receive all kinds of information from the outside world through mobile phones and computers,which leads to the challenge of education and teaching management in colleges and universities at present.

Convergence Analysis of the Legendre Spectral Collocation Methods for Second Order Volterra Integro-Differential Equations

A class of numerical methods is developed for second order Volterra integrodifferential equations by using a Legendre spectral approach.We provide a rigorous error analysis for the proposed methods,which shows that the numerical errors decay exponentially in the L∞-norm and L2-norm.Numerical examples illustrate the convergence and effectiveness of the numerical methods.

Convergence Analysis of the Spectral Methods for Weakly Singular Volterra Integro-Differential Equations with Smooth Solutions

The theory of a class of spectral methods is extended to Volterra integrodifferential equations which contain a weakly singular kernel(t−s)^(−μ) with 0<μ<1.In this work,we consider the case when the underlying solutions of weakly singular Volterra integro-differential equations are sufficiently smooth.We provide a rigorous error analysis for the spectral methods,which shows that both the errors of approximate solutions and the errors of approximate derivatives of the solutions decay exponentially in L^(∞)-norm and weighted L^(2)-norm.The numerical examples are given to illustrate the theoretical results.

Spectral method for multidimensional Volterra integral equation with regular kernel

This paper is concerned with obtaining an approximate solution for a linear multidimensional Volterra integral equation with a regular kernel. We choose the Gauss points associated with the multidimensional Jacobi weight function ω(x)=∏di=1(1-xi)^α(1+xi)^β,-1<α,β<1/d-1/2 (d denotes the space dimensions) as the collocation points. We demonstrate that the errors of approxima te solution decay exponentially. Numerical results are presen ted to demonstrate the effectiveness of the Jacobi spectral collocation method.

Small moleculeπ-conjugated electron acceptor for highly enhanced photocatalytic nitrogen reduction of BiOBr

Artificial ammonia synthesis using solar energy is of great significance as it can help narrow the gap to the zero-net emission target.However,the current photocatalytic activity is generally too low for mass production.Herein,we report a novel bismuth bromide oxide(BiOBr)-Tetracyanoquinodimethane(TCNQ)photocatalyst prepared via a facile self-assembly method.Due to the well-match band structure of TCNQ and Bi OBr,the separation and transfer of photogenerated electron-hole pairs were significantly boosted.More importantly,the abundant delocalizedπelectrons of TCNQ,and the electron-withdrawing property of TNCQ made electrons efficiently accumulated on the catalysts,which can strengthen the adsorption and cleavage of nitrogen molecules.As a result,the photocatalytic activity increased significantly.The highest ammonia yield of the optimized sample reached 2.617 mg/(h gcat),which was 5.6-fold as that of pristine BiOBr and higher than the reported BiOBr-based photocatalysts.The isotope labeled^(15)N_(2)was used to confirm that the ammonia is formed form the fixation of N_(2).Meanwhile,the sample also had good stability.After 4-time usage,the photocatalysts still had about 81.8%as the fresh sample.The results of this work provide a new way for optimizing the electronic structure of photocatalysts to achieve highly efficient photochemical N_(2) reduction.

A Spectral Method for Neutral Volterra Integro-Differential Equation with Weakly Singular Kernel

This paper is concerned with obtaining an approximate solution and an approximate derivative of the solution for neutral Volterra integro-differential equation with a weakly singular kernel.The solution of this equation,even for analytic data,is not smooth on the entire interval of integration.The Jacobi collocation discretization is proposed for the given equation.A rigorous analysis of error bound is also provided which theoretically justifies that both the error of approximate solution and the error of approximate derivative of the solution decay exponentially in L∞norm and weighted L2 norm.Numerical results are presented to demonstrate the effectiveness of the spectral method.