ABSTRACT
Objective:To analyze the changes in the number and workload of pediatricians, for evidences in further optimizing the allocation of pediatrician resources and formulating relevant policies in China.Methods:According to data from the National Bureau of Statistics and the " China Health and Health Statistics Yearbook", descriptive analysis was made to investigate the changes in the number and workload of pediatricians in China from 2010 to 2019.Results:During 2010 and 2019, the number of pediatric practitioners(assistants) increased from 115 800 to 158 500, and the growth rate was faster than that of the children aged 0-14 years, but slower than that of overall medical practitioners(assistants). The number of pediatric practitioners(assistants) per thousand children in China had grown steadily from 0.52 to 0.67, compared with the burden and the workload of medical practitioners nationwide, the workload of pediatricians was still relatively heavy.Conclusions:The number of pediatricians had increased gradually between 2010 and 2019, and the effects of various policies began to work, while the workload was still heavy. It is recommended to further develop a salary system and supporting policies in line with the characteristics of pediatrics sector, and focus on such problems as unbalanced and inadequate distribution of pediatricians.
ABSTRACT
Metal hydrides are regarded as promising hydrogen-supplying fuel for energetic materials while CL-20 (Hexanitrohexaazaisowurtzitane) and FOX-7 (1,1-Diamino-2,2-dinitroethylene) are typical principal components commonly used in energetic materials. Hence, it is interesting to explore the interactions between them for development of new energetic systems. In this paper, the adsorption and decomposition of CL-20 or FOX-7 molecules on the MgH2 (110) crystal surface were investigated by employing the First-Principles. In total, 18 adsorption configurations for CL-20/MgH2 (110) and 12 adsorption configurations for FOX-7/MgH2 (110) were considered. The geometric parameters for the configurations, adsorption energies, charge transfer, density of states, and decomposition mechanism were obtained and analyzed. In most of the configurations, chemical adsorption will occur. Moreover, the orientation of the nitro-group in CL-20 or FOX-7 with regard to the MgH2 (110) surface plays an important role on whether and how the energetic molecule decomposes. The adsorption and decomposition of CL-20 or FOX-7 on MgH2 could be attributed to the strong charge transfer between Mg atoms in the first layer of MgH2 (110) surface and oxygen as well as nitrogen atoms in the nitro-group of CL-20 or FOX-7 molecules.
Subject(s)
Bridged-Ring Compounds/chemistry , Ethylenes/chemistry , Magnesium/chemistry , Nitro Compounds/chemistry , Adsorption , Hydrogen/chemistry , Models, Chemical , Models, Molecular , Nitrogen/chemistry , Oxygen/chemistry , Surface PropertiesABSTRACT
Objective To establish the method for determining the content of cryptotanshinone and tanshinone ⅡA in Zhiwei Fuwei Wan. Methods The determination of cryptotanshinone and tanshinone ⅡA was performed on Symmetry C18 column with mobile phase consisted of acetonitrile-0.2%phosphate (60∶40) at flow rate of 1.0 mL/min. The detection wavelength was set at 262 nm. Results The linear ranges of cryptotanshinone and tanshinone ⅡA were 0.081 4-0.407 2 μg (r=0.999 7) and 0.163 6-0.81 8 μg (r=0.999 5) respectively, the average recoveries were 99.70% (RSD=1.37%) and 99.22% (RSD=0.94%) respectively. Conclusion The method is simple and rapid for the quality control of the product.
