Based on the principle that in the deformation zone the length of bore plain wire does not change, a mathematical model of the prefabricated hole flange-forming of unequal diameter tee pipe is established, for the difficult problem of the flange-forming prefabricated hole size design for tee pipe. To solve the mathematical model, a numerical method and a software system for The solution of the mathematical model is established. In order to verify the reliability of this article to build the mathematical model and its solution, taking engineering for example, apply the method of finite element simulation to verify the mathematical model and the solving system, and the results show that the mathematical model constructed in this paper can relatively accurately make calculation of prefabricated hole size of flange-forming of unequal diameter tee pipe.

Based on the principle that in the deformation zone the length of bore plain wire does not change, a mathematical model of the prefabricated hole for flange-forming of square hole tee pipe is established, for the difficult problem of the flange-forming prefabricated hole size design for square hole tee pipe. To solve the mathematical model, a numerical method and a software system for the mathematical model is established. In order to verify the reliability of the mathematical model and its solution, the method of finite element simulation is applied to verify the mathematical model and the solving system. The results show that the mathematical model constructed in this paper can relatively accurately make calculation of prefabricated hole size for flange-forming of square hole tee pipe.

Se concentration varies for different soil types, whether can be absorbed by plants is not related with the total amount of selenium, it is controlled by the bio-availability Se in soil. This paper is aim to look for the laws of the bio-availability Se in different soils, and find out an accuracy and effective method to extract the bio-available Se from different soil types. Digest the soil and tea leaves samples and used six methods (KH2PO4, NaHCO3, HAC, MgCl2, HCl, EDTA) to extract Se from the different soils, the result was measured by AFS. The mean values of total Se is 8.45μg/g in carbonaceous slates soil, 0.32μg/g and 0.41μg/g in malmstone soil, 0.78μg/g in shale soil. The maximum correlation coefficients (r) between the six extract methods and tea leaves about the extraction ratio of Se in four soils is 0.93188 with KH2PO4, 0.77097 and 0.83589 with NaHCO3, 0.84231 with HAC. So it can be indicate that the total Se contents is carbonaceous slates soil>shale soil>malmstone soil, the best extract method for carbonaceous slates soil, malmstone soil and shale soil are KH2PO4, NaHCO3, and HAC respectively.