The genetic composition of Poa annua L. populations with a series of traffic pollution was studied by starch electrophoresis. Five enzyme systems were stained. The results showed that: (1) Traffic pollution can dr...The genetic composition of Poa annua L. populations with a series of traffic pollution was studied by starch electrophoresis. Five enzyme systems were stained. The results showed that: (1) Traffic pollution can dramatically change genotypic frequencies at some loci of P. annua populations. Significant deviations from Hardy Weinberg equilibrium were observed on loci Fe 1 and Me due to the excess of heterozygotes in some populations. (2) The effective number of alleles per locus and the observed and expected heterozygosity were higher in the pollution series than in the clear control site(Botanic Park population), but the increase was not related with the pollution extent. (3) Most genetic variation was found within populations, and only 6 21% was among populations of the polluted series. Slightly higher differentiation( F ST =7 98%) was observed when the control population was included. (4) The calculated gene flow(Nm) is 2 8841 per generation. The mean of genetic identity is 0 9864 and the genetic distance average to 0 0138展开更多
We present the scheme of the structure of grading a resistor-heated system ofwarm compaction in powder metallurgy. The structure has the first heater and the second heater thatare heated by electrical tubes. Powder is...We present the scheme of the structure of grading a resistor-heated system ofwarm compaction in powder metallurgy. The structure has the first heater and the second heater thatare heated by electrical tubes. Powder is heated in turn in the first heater and the second heater,where there is the mass fluidity of powder under gravity. The dimensions of the first heater andthe second heater were calculated from the Fourier equation of heat conduction, and the boundarycondition was constant temperature. The drawings of the first heater, the second heater and thepowder-delivering device were given. The structure of the heat equipment is simple and easy tomanufacture. Finally, an exact warm compaction press system HGWY- II was developed for the heatingsystem.展开更多
文摘The genetic composition of Poa annua L. populations with a series of traffic pollution was studied by starch electrophoresis. Five enzyme systems were stained. The results showed that: (1) Traffic pollution can dramatically change genotypic frequencies at some loci of P. annua populations. Significant deviations from Hardy Weinberg equilibrium were observed on loci Fe 1 and Me due to the excess of heterozygotes in some populations. (2) The effective number of alleles per locus and the observed and expected heterozygosity were higher in the pollution series than in the clear control site(Botanic Park population), but the increase was not related with the pollution extent. (3) Most genetic variation was found within populations, and only 6 21% was among populations of the polluted series. Slightly higher differentiation( F ST =7 98%) was observed when the control population was included. (4) The calculated gene flow(Nm) is 2 8841 per generation. The mean of genetic identity is 0 9864 and the genetic distance average to 0 0138
文摘We present the scheme of the structure of grading a resistor-heated system ofwarm compaction in powder metallurgy. The structure has the first heater and the second heater thatare heated by electrical tubes. Powder is heated in turn in the first heater and the second heater,where there is the mass fluidity of powder under gravity. The dimensions of the first heater andthe second heater were calculated from the Fourier equation of heat conduction, and the boundarycondition was constant temperature. The drawings of the first heater, the second heater and thepowder-delivering device were given. The structure of the heat equipment is simple and easy tomanufacture. Finally, an exact warm compaction press system HGWY- II was developed for the heatingsystem.
