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1

Experimental and numerical investigations on dynamic tensile behavior of a ZrB2-SiC ceramic

He R., Cao J., Yang K., Wang L., Kong D.

Archives of Mechanics

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2023

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Vol. 75, nr 1-2

53--73

EN

The dynamic tensile behavior of a ZrB2-SiC ceramic was investigated via split Hopkinson pressure bar tests and a bond-based peridynamic model. The experimental results showed that the peak dynamic splitting tensile stress increased linearly with the strain rate. The dynamic tensile stress history and fracture pattern exhibited a significant strain-rate dependence. In simulation, the strain-rate dependent on the critical energy release rate was introduced to predict the dynamic tensile behavior of the ZrB2-SiC ceramic. The numerical results were in good agreement with the experimental results, verifying the applicability of the peridynamic model. The maximum error of the peak dynamic splitting tensile stress between the experimental and numerical results was no greater than 6%. Moreover, the effect of the strain rate on the fracture patterns of the ZrB2-SiC ceramic composite can be well predicted by the peridynamics method. The ZrB2-SiC composite specimen split into two large fragments with additional small fragments under dynamic splitting tension. With the increase of strain rate, the main crack propagation and branching led to a larger fracture region in the middle of the specimen.

2

Study of the force and deformation characteristics of subsea mudmat-pile hybrid foundations

Kong D., Deng M., Liu Y., Tan X.

Polish Maritime Research

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2018

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S 3

43--53

EN

To study the force and deformation characteristics of subsea mudmat-pile hybrid foundations under different combined loads, a project at a water depth of 200 m in the South China Sea was studied. A numerical model of a subsea mudmatpile hybrid foundation is developed using the numerical simulation software FLAC3D. The settlement of the seabed soil, the bending moments of the mudmat, and the displacements and bending moments along the pile shaft under different load combinations, including vertical load and horizontal load, vertical load and bending moment, and horizontal load and bending moment load, are analyzed. The results indicate that settlement of the seabed soil is reduced by the presence of piles. The settlement of the mudmat is reduced by the presence of piles. Different degrees of inclination occur along the pile shaft. The angle of inclination of pile No. 1 is greater than that of pile No. 2. The dip directions of piles No. 1 and No. 2 are identical under the vertical load and bending moment and are opposite to those under the other combined loads. The piles that are located at the junctions between the mudmat and the tops of the piles are easily destroyed.

3

Synthesis, Crystal Structures and Antibacterial Activities of a Pair of Isostructural Dinuclear Schiff Base Nickel(II) and Copper(II) Complexes

Sun Y., Kong D., Yang G., You Z.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 9

1457-1463

EN

Two novel dinuclear Schiff base complexes, [Ni2L2(NCS)2] (1) and [Cu2L2(NCS)2] (2), where L = 2-[(2-dimethylaminoethylimino)methyl]phenolate, have been synthesized and characterized by elemental analyses, IR, and single crystal X-ray diffraction. They are structurally similar. Each of the two metal ions of the complex is coordinated by two nitrogen and two oxygen atoms in the basal plane of a distorted square pyramid and by one nitrogen atom in its apex. The oxygen atoms belong to two Schiff base ligands and form bridges between two metal ions, while the nitrogen atoms of the basal plane belong to one ligand coordinated to a given metal atom. The apex nitrogen is that of the thiocyanate anion. The Schiff base and the two complexes showed effective antibacterial activities. It is noteworthy that the two complexes have stronger antibacterial activities than that of the corresponding Schiff base ligand.