This thesis presents a series of computational investigations into problems relating to the electronic structure of tetrel clusters containing one or more endohedral transition metals. The electronic properties of this class of cluster have been the focus of research for some time, driven in part by the diverse and typically highly symmetric structures that they adopt and also by the desire to miniaturise silicon-based electronic devices. Computational studies are of great importance in this field, particularly for the lighter tetrel clusters where structural information in the form of crystallographic data is entirely absent. Perhaps as a result of the absence of benchmarking data, many controversies have emerged in the literature, with different but apparently equally valid computational methodologies delivering very different conclusions on the structure of specific clusters. Our purpose in this thesis is to provide a deeper understanding of the factors that determine structural preference in this family of clusters, and hence shed some light on the reasons for the disagreements in the literature.
The pH-responsive hollow poly(acrylic acid) (HPAA) microspheres with regulated cavity structure and various shell thicknesses were synthesized. Their structural parameters and textural properties were characterized by various techniques. The ibuprofen loading results indicate the good drug loading capabilities of HPAA microspheres from 13.81 to 17.18%. Their ibuprofen release properties demonstrated their good pH sensitivity and distance-controlled drug diffusion process. Specially, the small-angle X-ray scattering technique was used to suggest the surface roughness and structural irregularities of HPAA before and after drug loading and releasing. These findings clearly indicate the potential of HPAA microspheres to be used as promising candidates in drug delivery.
Three metal-water (silver-water, copper-water and iron-water) nanofluids have been studied in this work by dynamic molecular method. The results indicate that Ag-water nanofluid posses greater thermal conductivity and thicker nanolayer due to the stronger interaction forces between Ag-water molecules. It is consistent with the results of adhesion theory. In addition, the thermal conductivity of nanofluids can be reflected by the proportion of energetic atoms to a certain extent. In order to evaluate the matching degree of phonon density of state (PDOS), an index named match degree of PDOS is proposed. It is found heat conduction can be enhanced by reducing PDOS mismatch. On the basis of conducted analysis and discussions, it is believed the phonon matching between metal and water molecules is the most crucial mechanism for the elevation of thermal conductivity of nanofluids. A new approach can be provided for the preparation of metal-water nanofluids with higher thermal conductivity.
Objective To explore the correlation between academic burnout and emotional intelligence in medical college students.Methods This survey was performed among 442 randomly selected college students using the emotional intelligence scale(EIS) Chinese-version and College Students Academic Burnout Scale.Results It showed that academic burnout total score was lower in female students than in male students except in accomplishment dimension.Emotional intelligence score was significantly higher in female students(137.46±15.07 v.s.102.96±18.63).In terms of grades,there were significant differences in total and dimensional score in academic burnout in different grade,but there was no significant difference in emotional intelligence score among different grades.Students from different regions showed no differences in scores of academic burnout and emotional intelligence.Academic burnout was negatively correlated with emotional intelligence(r=0.268,P0.05).Conclusion Academic burnout among college students is comparatively high.It should be paid more attention considering its close relation with emotional intelligence.
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