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Based on the stratified survey data of Pleonomus canaliculatus in the soil of winter wheat and summer maize rotation field in North China Plain, the vertical activity of Pleonomus canaliculatus in the soil of winter wheat and summer maize rotation fields, the correlation between meteorological conditions and farmland planting management are observed and analyzed, and effects of Pleonomus canaliculatus damage on the yield of winter wheat are analyzed. By combining the insect population weight index with population density index, characteristics of the harm-dormancy activity of Pleonomus canaliculatus are investigated comprehensively in different soil layers. Results show that in the winter wheat and summer maize rotation growing season, there are 3 harm and 3 dormant periods, 3 harm periods appear in the winter wheat regreening-jointing period, the summer maize seedling period and the autumn seedling period of winter wheat, and 3 dormant periods appear in winter wheat overwintering period, winter wheat ripening-harvesting period and summer maize filling-ripening period. Among 3 harm periods, winter wheat regreening-jointing period is the most serious, which could lead to serious yield reduction of winter wheat. Winter is warmer, and spring temperature is warmer early, so Pleonomus canaliculatus exhibits characteristics of going down late and coming up early, which shortens the dormant period in winter and prolong the harmful activity period. Soil temperature, moisture, and the relationship between food and source affect the damage, dormancy, and feeding activities of Pleonomus canaliculatus. The suitable soil moisture content for it is about 15% to 18%, and the suitable soil temperature is 14 to 18 ℃. In summer, Pleonomus canaliculatus may enter dormancy or reduce activity due to lack of food sources or high temperatures and humidity of soil, Pleonomus canaliculatus can enter the dormancy or reduced activity. The analysis of winter wheat yield reduction caused by Pleonomus canaliculatus damage shows that the yield reduction rate is increased by 5.1% with an increase of 10 m-2 in insect population density or with an increase of 1.0 g·m-2 in insect weight. Results provide reference for agricultural production in North China to address climate change and scientifically manage farm to avoid diseases and pests.

ObjectiveTo characterize the incidence of laboratory confirmed pertussis cases by immunization status in Ninghai County， and to provide evidence for improving pertussis prevention and control strategy in Ninghai County.MethodsData of reported pertussis cases in Ninghai County from 2018 to 2019 were collected through the National Notifiable Infectious Disease Reporting System. The immunization history of vaccines related to pertussis was collected through the Ningbo Immunization Planning Information Management System and field investigation. Descriptive epidemiological methods were used to analyze the collected data.ResultsThe respiratory secretions collected in the 64 cases tested positive for nucleic acid of Bordetella pertussis bacilli， of which 56.25% aged 0‒1 year. They were mainly pre-school children. No adolescent or adult case was reported. All cases had whooping cough. Of the cases， 78.13% had an increase in white blood cell count， 62.5% had an increase in lymphocyte percentage， 59.38% had completed three or more doses of pertussis vaccination， 69.39% had a time interval of >1 year between the onset and last dose of pertussis vaccination， and 31.25% reported close contact with pertussis patients before the onset. The misdiagnosis rate of pertussis was as high as 92.19%. In contrast， the prevalence of anti-pertussis IgG antibody in health population was 1.05%.ConclusionFurther improvement in the laboratory testing capacity can help clarify the diagnosis of pertussis. Generally， children aged 0-1 year are mainly affected， of which vast majority have received at least one dose of pertussis vaccination. Clinical symptoms are characterized by whooping cough. Additionally， elevated white blood cells and lymphocytes should be on the alert to pertussis infection.

As the last step of the nuclear fuel cycle, nuclear waste reprocessing is essential to the safe utilization and sustainable development of the nuclear industry and nuclear energy. Vitrification is currently internationally recognized as the best solution for the treatment of high-level radioactive waste, and it is also the only high-level waste disposal method that realizes engineering applications. The cold crucible induction melting (CCIM) vitrification technology is one of the key research directions of high-level waste liquid vitrification technologies. As an important part of the cold crucible, the bottom affects the magnetic permeability, sealing, strength and leakage process of the cold crucible. In order to improve the pouring efficiency during cold crucible melting process, the magnetic induction intensity near the discharge port needs to be enhanced. The effects of the design of the crucible bottom on the magnetic induction intensity and electromagnetic loss inside the cold crucible were studied. The 3D electromagnetic induction models of cold crucibles with different bottom structures were established by using the AC/DC module of COMSOL Multiphysics software. The simulation results show that changing the number of slits has little effect neither on the magnetic field inside the crucible, nor on the magnetic field and the electromagnetic loss at the bottom of the crucible. The slit width of crucible bottom increasing from 5 mm to 20 mm, the magnetic flux density inside the crucible increases by about 4%, and the electromagnetic loss of the glass melt domain in the crucible increases by about 1.7 kW (the proportion increased by about 6%). Increasing the length of the slits from 90 mm to 115 mm, the magnetic flux density near the center of the crucible bottom increases by 0.1-1.25 mT, and the electromagnetic loss of the glass melt near the bottom increases by 1.6% (about 0.4 kW). Accordingly, the magnetic permeability and the heating efficiency of the cold crucible can be improved by increasing the slit width. The magnetic induction intensity near the discharge port can be improved by increasing the length of the slits, thereby improving the leakage efficiency. In practical applications, it is not only necessary to improve the heating efficiency of the cold crucible, but also to avoid the leakage of the glass melt at the bottom of the cold crucible during the melting process. Therefore, the structural design of the cold crucible bottom needs to comprehensively consider factors such as the magnetic permeability, the heating efficiency, the strength of the crucible and the processing of water-cooled components inside the slits.