Method and device for measuring dynamic light scattering nanoparticles based on band-pass filtering

Abstract

The invention discloses a method and an apparatus for measuring dynamic light scattering nano-particles based on bandpass filtering. According to the invention, lasers are radiated on nano-particles performing Brownian motions in a solution. The scattered lights of the particles are directly detected; or the scattered lights of the particles are interfered with part of the original lights, and are detected; or the scattered lights are fed-back into a laser-tube cavity, self mixing is occurred, and self mixing signals are detected. Signals output by a photoelectric detector are pre-amplified, and are simultaneously delivered into a circuit formed by components of an M route buffer, bandpass filters with different central frequencies, and an RMS root-mean-square processor, which are connected in series, such that signal root-mean-square values at different frequencies with a number of M are obtained. The values are sampled by an A / D collecting card, such that power spectrum density functions at different frequencies with a number of M are obtained. With the method and the apparatus provided by the invention, a problem in prior arts of poor robustness of inverse calculations caused by seriously ill-conditioned coefficient matrix is solved. With the method and the apparatus provided by the invention, requirements on data collecting speed, data collecting amount, storage amount andprocessing amount are reduced; data processing time is reduced; and rapid measuring of nano-particle sizes can be realized.

Description

technical field [0001] The invention relates to a method and device capable of measuring nanoparticles, in particular to a method and device for measuring dynamic light scattering nanoparticles based on band-pass filtering, and belongs to the field of measurement technology. It can be used in many fields involving nanoparticle production and process control, such as scientific research, biomedicine, chemical energy, environmental protection, etc. [0002] Background technique [0003] In the dynamic light scattering nanoparticle measurement technology, the autocorrelation function of the scattered light signal is obtained by a digital correlator or the power spectral density function of the scattered light signal is obtained by the power spectrum estimation method, and the particle size of the nanoparticle is obtained by matrix inversion. diameter distribution parameters. [0004] The laser light emitted by the laser is combined by a single or multiple lenses to form conve...

AI Technical Summary

Problems solved by technology

However, no matter the inversion based on the autocorrelation signal or the inversion based on the power spectrum signal, the coefficient matrix is ​​seriously ill-conditioned, such as Figure 5 As shown, a small measurement signal error will lead to a huge deviation of the particle size distribution, and even get a wrong particle size distribution

This limits the reliability of the particle size

Secondly, the processing of autocorrelation signals requires expensive digital correlators, and the power spectrum estimation of dynamic scattered light requires high data acquisition card (A / D card) sampling rate, large computer storage resources and a certain amount of CPU processing time. Bad for cost control and real-time measurement

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