| 摘要 |
1481451 Measuring the mass and distribution of particles BLOCK ENG Inc 16 Sept 1974 [23 Oct 1973] 40233/74 Heading G1A In an apparatus for measuring the mass and distribution of particles, e.g. viruses, in a sample 20 that may be treated chemically so that they fluoresce, the light emanating from the particles after they have been subjected to radiation from a laser source 22 is received by a photo-multiplier 30. The light reaching the photo-multiplier passes through a spatial filter 38, e.g. a lire screen, microscope type viewing optics 24 and a filter 26 which is restricted to the fluorescent wavelengths. The detector's output is passed via a D.C. filter 32 and a R.M.S. converter 34 to provide steady state signals representative of "T", the average total D.C. signal in the detector output, and "R", the root mean square value of the oscillations in the detector output. These signals are then processed as shown to supply two display devices representing the statistical particle distribution N=T<SP>2</SP>/(R<SP>2</SP>-T), or the mass M of the dye bound to each particle M = (R<SP>2</SP>-T)/KT. An alternative similiar digital signal processing system Fig. 2 (not shown), is disclosed.
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