Objective: To evaluate the effect of chewing sugar-free gum on gastrointestinal function recovery after cesarean section. Methods: Randomized controlled trials comparing the use of chewing gum in postoperative recover...Objective: To evaluate the effect of chewing sugar-free gum on gastrointestinal function recovery after cesarean section. Methods: Randomized controlled trials comparing the use of chewing gum in postoperative recovery with a control group were retrieved from the databases including Pubmed, Cochrane Library, Science Direct, Web of Science, CBM, CNKI, Wanfang and VIP, et al. After screening literatures, evaluating the quality of studies, extracting data, the RevMan5.3 software was used for data analysis. Results: A total of 13 RCTs including 2233 patients were analyzed in the study. The results showed that chewing gum after cesarean delivery can effectively shorten the recovery time of bowel sounds, passage of flatus and first defecation (all P Conclusion: Chewing sugar-free gum after cesarean section can promote the early recovery of gastrointestinal function, but the side effects of chewing gum are still unclear, which needs more clinical, large sample and high-quality studies to further verify.展开更多
A novel frequency selective surface （FSS） for reducing radar cross section （RCS） is proposed in this paper. This FSS is based on the random distribution method, so it can be called random surface. In this paper, t...A novel frequency selective surface （FSS） for reducing radar cross section （RCS） is proposed in this paper. This FSS is based on the random distribution method, so it can be called random surface. In this paper, the stacked patches serving as periodic elements are employed for RCS reduction. Previous work has demonstrated the efficiency by utilizing the microstrip patches, especially for the reflectarray. First, the relevant theory of the method is described. Then a sample of a three-layer variable-sized stacked patch random surface with a dimension of 260 mm x 260 mm is simulated, fabricated, and measured in order to demonstrate the validity of the proposed design. For the normal incidence, the 8-dB RCS reduction can be achieved both by the simulation and the measurement in 8 GHz-13 GHz. The oblique incidence of 30° is also investigated, in which the 7-dB RCS reduction can be obtained in a frequency range of 8 GHz-14 GHz.展开更多
文摘Objective: To evaluate the effect of chewing sugar-free gum on gastrointestinal function recovery after cesarean section. Methods: Randomized controlled trials comparing the use of chewing gum in postoperative recovery with a control group were retrieved from the databases including Pubmed, Cochrane Library, Science Direct, Web of Science, CBM, CNKI, Wanfang and VIP, et al. After screening literatures, evaluating the quality of studies, extracting data, the RevMan5.3 software was used for data analysis. Results: A total of 13 RCTs including 2233 patients were analyzed in the study. The results showed that chewing gum after cesarean delivery can effectively shorten the recovery time of bowel sounds, passage of flatus and first defecation (all P Conclusion: Chewing sugar-free gum after cesarean section can promote the early recovery of gastrointestinal function, but the side effects of chewing gum are still unclear, which needs more clinical, large sample and high-quality studies to further verify.
文摘A novel frequency selective surface （FSS） for reducing radar cross section （RCS） is proposed in this paper. This FSS is based on the random distribution method, so it can be called random surface. In this paper, the stacked patches serving as periodic elements are employed for RCS reduction. Previous work has demonstrated the efficiency by utilizing the microstrip patches, especially for the reflectarray. First, the relevant theory of the method is described. Then a sample of a three-layer variable-sized stacked patch random surface with a dimension of 260 mm x 260 mm is simulated, fabricated, and measured in order to demonstrate the validity of the proposed design. For the normal incidence, the 8-dB RCS reduction can be achieved both by the simulation and the measurement in 8 GHz-13 GHz. The oblique incidence of 30° is also investigated, in which the 7-dB RCS reduction can be obtained in a frequency range of 8 GHz-14 GHz.
