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Partial denitrification(PD) can reduce nitrate to nitrite, and is an important way to provide substrates steadily in anaerobic ammonia oxidization(ANAMMOX) reaction. PD has great potential in energy-efficient biological nitrogen removal of wastewater, and has become a research hotspot in recent years. In this work,the mechanism of PD was introduced from the aspects of its biological process and functional microorganisms. Then the key factors affecting the PD process, such as carbon source, carbon-nitrogen ratio, environmental conditions, and heavy metals, etc. were summarized. Moreover, the research on PD in biological nitrogen removal process in recent years was also reviewed. Finally, the problems existing in the current research and the aspects for further research of PD were discussed. This work is expected to provide theoretical supports for the development and application of PD in biological nitrogen removal of wastewater.

A strain D5 with excellent partial denitrification performance was screened from paddy soil. The bacteria were identified as Klebsiella pneumoniae by morphological observation and 16S r DNA sequence analysis. The denitrification ability of strain D5 under different environmental factors （carbon source，C/N ratio and temperature） were investigated using single-factor experiments. The results showed that various environmental factors had obvious influence on partial denitrification of strain D5. The optimal conditions for partial denitrification activity of strain D5 were carbon source of sodium citrate， C/N ratio of 3，temperatures of 25 ℃ and 35 ℃. The results showed that strain D5 had excellent partial denitrification performance，and the optimal partial denitrification effect could be achieved by regulating environmental conditions.

This paper concentrates on the error estimation of novel time second‐order splitting conservative finite difference method (FDM) for high‐dimensional nonlinear fractional Schrödinger equation rigorously. The discrete preservation property of our scheme is exhibited. By virtue of the cut‐off technique and discrete energy method, it is shown that our scheme possesses the accuracy of O(Δt2+hx2+hy2) in sense of L2‐ norm. Numerical experiments are exhibited to validate the accuracy and conservation property of our scheme. [ABSTRACT FROM AUTHOR]

In this work, a spherical Sn-MOF precursor was synthesized through hydrothermal method using 1,3,5-benzenetricarboxylic acid (H3BTC) as the organic ligand. Sn-MOF-200, Sn-MOF-250, and Sn-MOF-300 were obtained at different annealing temperatures. Among them, the Sn-MOF-250 composite obtained by annealing at 250 ℃ was stable in structure, and the specific surface area is 118.8 m2 g−1. The specific capacity of Sn-MOF-250 can be maintained up to 846.6 mA h g−1 after 110 cycles at the current density of 100 mA g−1 when used as the anode material of lithium-ion battery. The excellent cycling performance of Sn-MOF-250 is due to the special framework structure of metal–organic frameworks (MOFs). After combining with Sn ion, the metal–organic coordination compound formed can greatly improve the diffusion and transport efficiency of lithium ion. This facile synthesis strategy has a certain application prospect in the development of high-performance lithium-ion battery anode materials. [ABSTRACT FROM AUTHOR]

In this paper, we present a nonconforming immersed finite element method for solving elliptic optimal control problems with interfaces. The immersed finite element space is constructed based on the rotated-Q1 nonconforming finite elements with the integral-value degrees of freedom. The method can overcome the difficulties encountered by conforming immersed finite element method. We derive error estimates for the control, state and adjoint state in both energy and L 2 norms. Numerical results are reported to support the theoretical analysis. [ABSTRACT FROM AUTHOR]

In this paper, by applying order reduction approach, a second-order accurate box scheme is established to solve a nonlinear delayed convection-diffusion equations with Neumann boundary conditions. By the discrete energy method, it is shown that the difference scheme is uniquely solvable, and has a convergence rate of with respect to - norm in constrained and non-constrained temporal grids. Besides, for constrained temporal step, a Richardson extrapolation method (REM) used along with the box scheme, which makes final solution third-order accurate in both time and space, is developed in detail. Finally, numerical results confirm the accuracy and efficiency of our solvers. [ABSTRACT FROM AUTHOR]