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SF6 is a greenhouse gas. Finding an alternative gas for SF6 has become an urgent problem in the switch field. In order to explore the feasibility of replacing SF6 gas with dry air directly, CO2 and C4F7N/CO2 mixed gas, based on the KYN28‐12 medium voltage switchgear, the finite element method was used to solve the three‐dimensional coupled multi‐physics of the switchgear in this paper. From the angle of the temperature field and flow field, the temperature rise characteristics under different operation conditions were analyzed. The results showed that the temperature field and flow field distribution under the four gases were similar. Among them, the temperature rise of SF6 gas was the smallest, followed by the C4F7N/CO2 mixed gas, CO2 and dry air. The flow rate of SF6 gas was the lowest, about 0.11 m/s. The flow velocities of other gases were relatively close. When the switchgear was filled with the same gas, as the inflation pressure increased, the temperature rise of the switchgear decreased and the gas flow rate also dropped to a certain extent. The temperature field and flow field of the switchgear under the C4F7N/CO2 mixed gas at 0.2 Mpa were similar to those under the 0.1 Mpa SF6 gas. Under the C4F7N/CO2 mixed gas, the contact failure of the plum contact made the temperature rise of the switchgear increase overall. The maximum temperature rise point transferred to the contact failure. The temperature rise further rose with the increase of the contact failure degree. The gas flow rate also greatly increased with the failure degree elevated. From the perspective of temperature rise, the C4F7N/CO2 mixed gas has the possibility of being applied in the electrical equipment under the premise of meeting the insulation conditions. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies of the association between the metabotropic glutamate receptor 3 gene (GRM3) and schizophrenia have produced conflicting results, although GRM3 is a promising candidate gene. Fujii et al. found a single nuclear polymorphism (SNP) for within this gene, rs1468412 to have a positive association to schizophrenia in Japanese patients. To investigate this further, we genotyped 7 SNPs around GRM3 including rs1468412, in 752 Chinese patients with schizophrenia and 752 controls using Taqman technology. We did not detect any association between rs1468412 and schizophrenia, however we found differences in the allele frequency distribution of SNP rs2299225 (p=0.0297, odds ration [OR]=1.44, 95% confidence interval 1.05–1.99) between cases and controls. Moreover, the overall frequency of haplotypes constructed from three SNPs including rs2299225 showed significant differences between cases and controls (p=0.0017). Our results partially support the previous studies in other ethnic groups and indicate that the GRM3 gene may play an important role in the etiology of schizophrenia in the Han Chinese. [Copyright &y& Elsevier]