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Objective: To investigate the clinical evaluation of unilateral vertebroplasty for OVCF. Methods: A retrospective analysis was performed on 60 patients treated with PVP from January 2020 to December 2021. Patients were divided into two groups according to the treatment method, 30 patients in the PVP group received PVP and 30 patients in the PCVP group received PCVP. The VAS score, ODI score, bone cement dosage, and leakage were compared between the two groups preoperatively, immediately postoperatively, and 7 and 30 days postoperatively. Results: VAS scores in the PCVP and PVP groups before, immediately after, and 7 days after surgery were P > 0.05, and the difference was not statistically significant; ODI score in group 1 before surgery was not statistically significant (P > 0.05); bone cement injection volume in the PVP group was significantly higher than that in the PCVP group (P < 0.05), and the difference was statistically significant; the difference in bone cement leakage between the two groups was not statistically significant (P > 0.05). Conclusion: Under the same puncture conditions, the PCVP group used the method of injection while retreating to achieve a better bone cement dispersion effect by using less bone cement and achieving uniform dispersion of bone cement. It can relieve the patients' back pain and improve the back function.
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INTRODUCTION: As an important advanced functional material, the memory effect of nitinol shape memory alloy (SMA) is the focus of research. According to the current research, the memory function of the alloy decreases after welding, and there is no sufficient explanation for the phenomenon. OBJECTIVES: For the problem, this research is to explore the underlying causes of the decrease of shape memory function after welding by analyzing the microstructure and micro defects. METHODS: The vacuum electron beam welding tests of 1â¯mm thick Ni50Ti50 alloy plate was carried out to determine the appropriate welding process parameter. And the shape memory function of the welded joint was compared with that of the base metal to analyze the change of memory function. RESULTS: It was found that the shape memory function of the welded joint decreased significantly under different strain variables. And the phase transition temperature also changed. CONCLUSIONS: This was due to the micro stress field produced by non-equilibrium solidification in molten pool promoted the formation and propagation of dislocations, increasing the dislocation density in the martensite. Dislocations entangled with each other in the martensite, showing a grid-like distribution, which destroyed the integrity of martensite substructure. At the same time, the twin substructure of martensite was often accompanied by vacancies, dislocations, stacking faults, and a consequently large stress field formed between twin planes due to lattice distortion. Secondary twin was identified inside martensite under micro shear stress, where the martensite showed the bending state. The habitual relationship between martensite phase and parent phase was destroyed, resulting in the decrease of shape memory function.
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The dynamic characteristics of evapotranspiration in latored soil on hills of subtropics regions in south China was analyzed. The results showed that evapotranspiration presented annual and seasonal fluctuations. The maximum monthly evapotranspiration was 10.80-15.41 times of the monthly minimum. The evapotranspiration in wet season (March to September) accounted for about 77% of annual total evapotranspiration, and that in dry season (October to February of next year) accounted for about 23%. Although the amount of annual rainfalls could balance annual total evapotranspiration, rainfalls were insufficient for evapotranspiration in the dry season, and soil water could be depleted by evapotranspiration. Based on the modified Penman equation, the calculation model of evapotranspiration in latored soil on hills of subtropics regions in south China was set up. By comparing modeling results with experimental data, it was proved that the calculation model was very reliable.