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In order to support diverse service demands of communication scenarios, 5G adopts the mixed-numerology system based on orthogonal frequency division multiplexing (OFDM).The mixed-numerology systems still have the problem of high peak-to-average power ratio (PAPR).Furthermore, its design structure makes it difficult to apply traditional PAPR suppression methods straight forwardly, in which mixed signals are generated by superimposing multiple sub-signals with different parameters.An optimization model for minimizing PAPR in mixed-numerology systems was established based on tone reservation method.Utilizing the characteristic of single-peak of time-domain kernel, the multiple copies were generated in different numerologies based on the peak position of the mixed signal.The mixed time-domain kernel was then superimposed to reduce the peaks of the mixed signal.Since the proposed algorithm didn’t require inverse fast Fourier transform (IFFT)/ fast Fourier transform (FFT) operations during iteration, it had relatively low computational complexity.Simulation results show that the proposed algorithm effectively reduces the PAPR of mixed signals.

Based on the essence of satellite internet, the development status of satellite internet industry from three aspects of evolution path, global deployment and industrial chain was introduced. The operation mode of foreign satellite internet companies. was analyzed On this basis, combined with the network characteristics of the space-integrated-ground information network, and aimed at its basic business, the operation mode of the space-integrated-ground information network was proposed. Finally, the development suggestions of the application and operation of the space-integrated-ground information network were given.

The tail-sitter Vertical Takeoff and Landing (VTOL) Unmanned Aerial Vehicle(UAV), flying in a fixed-wing model, overcomes many shortcomings of traditional fixed-wing UAVs, and inherits the advantage of high overall efficiency, which means it has great development potential and very broad application prospects. The attitude of tail-sitter VTOL UAV shows a wide change range in its takeoff and landing stages, and when the attitude sensor changes more than 90 degrees in pitch direction, the Euler angles converted by the Quaternions will have singular points, which means gimbal deadlock appears. From the solution algorithm, this paper provides a method of changing the order of rotation to avoid the appearance of singular points. The results show that this method can be well applied to the attitude solution of the VTOL UAV.

[Objective] As an important part of the energy system, renewable energy is one of the key driving forces to build the low-cost, clean and low-carbon, safe, and efficient new energy system. Exploring the regional differences, distribution dynamics, and convergence of China’s renewable energy development level will help to deeply understand the current situation and evolution trend of China’s renewable energy development level, and provide policy guidance for China to further promote the energy revolution, build a new energy system, and achieve the dual carbon goals. [Methods] Based on China’s provincial panel data from 2006 to 2019, Dagum Gini coefficient, Kernel density, σ convergence, and spatial β convergence were used to analyze the detailed characteristics of China’s renewable energy development level. [Results] (1) The renewable energy development level in China and the four regions of eastern, central, western, and northeastern China exhibited a steady rising trend, and the average annual growth rate in the Northeast was the highest; (2) The intraregional differences in the whole country and the four regions gradually decreased. The interregional imbalance was the main source of the overall difference, and its impact on the overall difference was increasing. (3) With regard to the distribution dynamics, the development level of renewable energy in China exhibited a significant spatial correlation. Polarization occurred in the four regions, but gradually weakened. (4) On the convergence side, the renewable energy development level of China as a whole and the four regions all showed the characteristics of σ convergence and β convergence, which was the strongest in the Northeast and the weakest in western China. [Conclusion] The development level of renewable energy in China possesses great potential for further improvement, and exhibited obvious regional differences and spatial spillover effects. Therefore, the Chinese government should attach importance to the development of renewable energy, and different regions should formulate differentiated incentive policies according to local conditions. The regions should strengthen regional exchanges and cooperation, promote mutual interaction, and jointly contribute to the realization of the dual carbon goals.

Silver plating can be divided into replacement plating and electroplating.In order to compare the corrosion resistance and galvanic corrosion behavior of coatings prepared by these two methods，the corrosion resistance and galvanic corrosion behaviors of the ZHL-02 replacement plating and ZHL-02 electroplating coatings in cyanide-free silver plating process using 5，5-dimethylamide as the main complexing agent were analyzed by scanning electron microscopy，XRD，electrochemical workstation，Tafel curve and galvanic corrosion methods.Results showed that the replacement coating had better crystallization and more complete coverage，and its resistance to galvanic corrosion was slightly better than that of the electroplating coating under the same thickness.With the prolongation of replacement silver plating time，the self-corrosion rate of the coating gradually decreased.However，the replacement plating took a long time，and it was difficult to obtain a thickness of more than 1 μm，which limited its application to a certain extent.Compared with replacement plating，the plating speed of electroplating was much faster，the silver coating ＞2.4 μm could be obtained for 5 min.As the extension of electroplating time，larger particles would appear in the silver coating，forming defective structures such as tiny pores.When the electroplating silver times were 1，2，and 5 min，the corresponding self-corrosion rates were 7.15×10-3，5.30×10-3 and 4.27×10-3 mm/a respectively.Besides，when the electroplating time was extended from 1 min to 2 min and then to 5 min，the average galvanic corrosion rate of the coating decreased first and then increased.

As a novel widely used drug, sodium-glucose co-transporter (SGLT) 2 inhibitor may lower blood glucose in type 2 diabetics through blocking SGLT2 to curtain glucose reabsorption in proximal renal tubular cells. At the same time, this drug may bring significant renal and cardiovascular benefits to both diabetics and non-diabetics. Human peritoneal mesothelial cells (HPMCs) from peritoneal dialysis (PD) patients can express SGLT. Studies of SGLT2 inhibitors in PD have been reported in in vitro or animal experiments. Using SGLT2 inhibitors in PD patients can reduce peritoneal glucose absorption and delay the progress of peritoneal fibrosis. At the same time, prolonged use of peritoneum and maintenance of transport function are conducive to ensuring dialysis adequacy and optimizing the prognosis. However, application of SGLT2 inhibitors during PD has not attracted extensive attention. This review focused upon the developments of peritoneal glucose metabolism and SGLT2 inhibitors during PD.

ObjectiveTo explore the prevalence and indoor environment risk factors of pneumonia among preschool children in Urumqi city of Xinjiang Uygur Autonomous Region for providing evidences to the prevention of the disease.MethodsUsing stratified random cluster sampling, we recruited 10 000 children aged 2 – 7 years in 60 kindergartens in 6 districts of Urumqi city. Then we conducted a self-administered survey among the parents of the selected children during August 2019 using a self-designed questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC) and Dampness in Buildings and Health (DBH).ResultsAmong 8 153 children with valid information provided by their parents, the prevalence of doctor-diagnosed pneumonia was 29.5%. Multivariate logistic regression results revealed that the children exposed to following indoor conditions were more likely to have pneumonia: home decoration or installation of new furniture during the period from maternal pregnancy to age of one year (odds ratio [OR] = 1.18, 95% confidence interval [95% CI]: 1.04 – 1.35), emergence of cockroaches, flies or mosquitoes at home (OR = 1.69, 95% CI: 1.49 – 1.91), plantation of flowering plants in the house since children′s birth (OR = 1.19, 95% CI: 1.07 – 1.32), keeping pets at home since children′s birth (OR = 1.31, 95% CI: 1.15 – 1.49), and exposed to passive smoking at home (OR = 1.31, 95% CI: 1.19 – 1.45).ConclusionPneumonia prevalence is relatively high and influenced by several indoor environment risk factors among preschool children in Urumqi city. The results suggest that some indoor conditions need to be improved for pneumonia prevention in the children.