First-principles calculations of structural and thermodynamic properties of β-PbO

We employed ab-initio calculations to investigate the structural and thermodynamic properties of Massicot or orthorhombic phase of PbO named β-PbO using the projector augmented-wave（PAW） method within the generalized gradient approximation（GGA）. The temperature and pressure dependence of bulk modulus, heat capacity at constant pressure and constant volume, entropy, thermal expansion coefficient and Grüneisen parameter were discussed. Accuracy of two different models, the Debye and Debye-Grüneisen which are based on the quasi-harmonic approximation（QHA） for producing thermodynamic properties of material were compared. According to calculation results, these two models can be used to designate thermodynamic properties for β-PbO with sensible accuracy over a wide range of temperatures and pressures, and our work on the properties of this structure will be useful for more deeply understanding various properties of this structure.

Erratum to:“An Approximate Method for Calculating the Fluid Force and Response of A Circular Cylinder at Lock-in” [China Ocean Engineering,22(3),2008,371-384]

Because of my carelessness,Eq.（1）in the paper "An approximate method for calculating the fluid force and response of a circular cylinder at lock-in"(China Ocean Engineering,22（3）,2008,pp.373)should be f’-1.0/U’-5.0=f’;-1.0/5.75f’;-5.0,not f’=U’/5.75. My apology is hereby given.

Approximate Calculation of U-shaped Bellows

U shaped bellows are widely used for sealed connections that require some flexibility. Since the structure of U shaped bellows is complex,numerical methods are often used to calculate mechanical parameters such as stiffness, displacement, etc. In this paper approximate formulas are derived for calculating the stiffness and the stresses of a U shaped bellows with a slender ring shell. These formulas can be used for designing bellows and selecting corrugation parameters. Comparison between the results of the approximate caculation and a finite element calculation showed that the approximate formulas are applicable for μ<0 5.

swSpAMM:optimizing large-scale sparse approximate matrix multiplication on Sunway Taihulight

Although matrix multiplication plays an essential role in a wide range of applications,previous works only focus on optimizing dense or sparse matrix multiplications.The Sparse Approximate Matrix Multiply(SpAMM)is an algorithm to accelerate the multiplication of decay matrices,the sparsity of which is between dense and sparse matrices.In addition,large-scale decay matrix multiplication is performed in scientific applications to solve cutting-edge problems.To optimize large-scale decay matrix multiplication using SpAMM on supercomputers such as Sunway Taihulight,we present swSpAMM,an optimized SpAMM algorithm by adapting the computation characteristics to the architecture features of Sunway Taihulight.Specifically,we propose both intra-node and inter-node optimizations to accelerate swSpAMM for large-scale execution.For intra-node optimizations,we explore algorithm parallelization and block-major data layout that are tailored to better utilize the architecture advantage of Sunway processor.For inter-node optimizations,we propose a matrix organization strategy for better distributing sub-matrices across nodes and a dynamic scheduling strategy for improving load balance across nodes.We compare swSpAMM with the existing GEMM library on a single node as well as large-scale matrix multiplication methods on multiple nodes.The experiment results show that swSpAMM achieves a speedup up to 14.5×and 2.2×when compared to xMath library on a single node and 2D GEMM method on multiple nodes,respectively.