This paper reports the observed changes for equilibrium factors between 226Ra and 222Rn with sealing time of the samples. The samples include soil, raw coal, mineral water, cement, rock, etc. Especially the conception...This paper reports the observed changes for equilibrium factors between 226Ra and 222Rn with sealing time of the samples. The samples include soil, raw coal, mineral water, cement, rock, etc. Especially the conceptions of “pre-equilibrium time” and “pre-equilibrium factor” have been put forward and methods of measuring and proc- essing data have been given which can be used for rapidly reporting activity of 226 Ra in samples with unknown equi- librium factor. It is definitely concluded that, using methods given in the paper, a test report will be completed in 3~7 days, instead of one month, after receiving the sample whose activity is not lower than LLD of the spectrometer.展开更多
The incipient condition of hang-up for three Geldart-D powders has been experimentally studied in a 21 m long standpipe hopper system. Experimental results show that the pressure gradient for hang-up to occur is indep...The incipient condition of hang-up for three Geldart-D powders has been experimentally studied in a 21 m long standpipe hopper system. Experimental results show that the pressure gradient for hang-up to occur is independent of the materials height in the hopper and the diameter of orifice and equals to (dpw/dl)s, which can be predicted by Eq. (7). While the corresponding gas velocity in the standpipe equals to the incipient fluidized velocity of particles at the high pressure and can be predicted by Kwauk's equation.展开更多
文摘This paper reports the observed changes for equilibrium factors between 226Ra and 222Rn with sealing time of the samples. The samples include soil, raw coal, mineral water, cement, rock, etc. Especially the conceptions of “pre-equilibrium time” and “pre-equilibrium factor” have been put forward and methods of measuring and proc- essing data have been given which can be used for rapidly reporting activity of 226 Ra in samples with unknown equi- librium factor. It is definitely concluded that, using methods given in the paper, a test report will be completed in 3~7 days, instead of one month, after receiving the sample whose activity is not lower than LLD of the spectrometer.
文摘The incipient condition of hang-up for three Geldart-D powders has been experimentally studied in a 21 m long standpipe hopper system. Experimental results show that the pressure gradient for hang-up to occur is independent of the materials height in the hopper and the diameter of orifice and equals to (dpw/dl)s, which can be predicted by Eq. (7). While the corresponding gas velocity in the standpipe equals to the incipient fluidized velocity of particles at the high pressure and can be predicted by Kwauk's equation.
