No abstract

Enrofloxacin is a poorly soluble antibacterial drug of the fluoroquinolones class used in veterinary medicine. The main purpose of this work was to investigate the structural and pharmaceutical properties of new enrofloxacin salts. Enrofloxacin anhydrate and its organic salts with tartaric acid, nicotinic acid and suberic acid formed as pure crystalline anhydrous solids. All the crystals were grown from a mixed solution by slow evaporation at room temperature. These products were then characterized by field-emission scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry. Further, X-ray single crystal diffraction analysis was used to study the crystal structure. The intermolecular interactions and packing arrangements in the crystal structures were studied, and the solubility of these salts in water was determined using high-performance liquid chromatography. The results show that the new salts of enrofloxacin developed in this study exhibited excellent water solubility.

Pile driven-operations is an important means to control floods, anti-flood spiral pile is a kind of flood control equipment which is lightweight, high work efficiency and low labor intensity. It is important to research the soil variables to further clarify the mechanism of pile-soil interaction in driven process. Soil constitutive model was built as the SPH particles; pile-driven process was simulated by dynamics software. By tracing the SPH (Smoothed Particle Hydrodynamics) particles, contrasting and analyzing the movement of soil particles at different times and depths because of friction, extrusion, and shear effect of pile were achieved. The mechanism of pile - soil interaction in the driven process was clarified by analyzing and comparing the simulation results, which make up the lack of theoretical analysis and experimental methods. It will provide useful suggestions on the design of spiral pile and reducing the secondary damage to dam.

Pile-driven operation is the essential means of flood control and river harnessing. Anti-flood Spiral Pile is an innovative flood fighting and rescue equipment. Based on the experiment, established the spiral pile finite element model in FEM method and constructed the soil model with SPH smooth particles, set the keywords and parameters by using LS-DYNA softwares own processor, and then, the large deformation (soil extrusion and shearing status, etc.) and stress conditions be simulated truthfully. With reference to the experiment, the simulation results of SPH method with ALE method was contrasted, which could provide a reliable reference and scientific basis for the subsequent analysis and design of the spiral pile.