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The study aimed to analyze the value and significance of magnetic resonance imaging (MRI) using biocompatible Au-Fe3O4 nanomaterials in the diagnosis of liver tumors. In this study, 124 patients with liver tumors were selected to perform MRI scanning based on Au-Fe3O4 nanoparticles. The coincidence rate between MRI scanning results and pathological examination results, the detection rate of tumor focus between MRI scanning results and CT detection results were analyzed, to evaluate the diagnostic performance of MRI scanning based on Au-Fe3O4 nanoparticles. The results showed that in the detection of primary tumors, secondary tumors, and focal nodular hyperplasia, the coincidence rate between MRI scanning results and pathological examination results was high, and Kappa values were all greater than 0.8. Compared with the results of CT, the detection rate of tumor lesions smaller than 1 cm by MRI was significantly higher (P0.05), but there was no significant difference between the two diagnostic methods for tumor lesions larger than 1 cm (P0.05). Additionally, the accuracy, specificity, and sensitivity of MRI in diagnosing liver tumors were 86.81, 84.29, and 77.27, respectively. Clinically, MRI scanning based on Au-Fe3O4nanoparticles can provide a practical and effective reference for the differential diagnosis of liver tumors.

High-power laser systems mostly use coherent or incoherent combined beams to achieve higher laser output power to satisfy the application. However, the far-field beam quality of laser will be reduced when propagating over atmosphere. Based on the propagation model of laser beams array, we use atmospheric coherence length, laser duration and average wind velocity to construct dynamic atmospheric turbulence which is characterized as a phase screen sequence. Meanwhile, considered as the indexes to evaluate beam quality, peak intensity and intensity in bucket are comparatively analysed in coherent and incoherent combined beams in far-field. The results indicate that in weaker turbulence circumstances, coherent combined beam has an advantage compared with the incoherent combined beams when laser duration is short, and coherent combination is more suitable for pulsed laser. With laser duration is increasing, the beam quality of incoherent and coherent combined beams both decrease and tend to be close. In stronger turbulence circumstances, the corresponding laser duration will be shorter when the beam quality of coherent combined beams is extraordinary close to that of incoherent combined beams. The researches can provide important data for high-power laser system to select the optimal beam combination mode to improve its performance.

K 2 O/ZrO 2 and K 2 O/ZrO 2 -La2O 3 -x (x=0.4%, 0.5%, 0.6%, 0.7% and 0.8%) catalysts for the synthesis of di-2-ethylhexyl carbonate from dimethyl carbonate and 2-ethyl hexanol were prepared by impregnation method calcinated at 773K, 873K and 973K. The activity of K 2 O/ZrO 2 -La2O 3 -0.6% catalyst reached the yield of 81.18% for di-2-ethylhexyl carbonate when the calcination temperature was 973K. XRD and Raman measurements of catalysts revealed that the tetragonal and monoclinic zirconia phase were observed in the catalysts. It was benefited to increase the basicity of catalysts that K 2 O dispersed on the surface of the carrier. The monoclinic zirconia phase decreased when the content of La increased.