CN104330347B - SPAMS surveys gasoloid core-shell structure particles optical parametric nonlinear inversion - Google Patents

Abstract

Translated fromChinese

本发明公开了一种基于SPAMS实测气溶胶核壳结构球体单颗粒的光学参数非线性反演方法，包括：采用SPAMS检测不同粒径光学性质参数已知的PSL小球，然后得出实测PSL小球的散射强度；同时，根据Mie散射理论结合SPAMS的椭球反射镜几何参数得出SPAMS所测PSL小球的光学散射理论响应；将PSL小球的光学散射理论响应和SPAMS实测得到的散射强度进行线性拟合，得到实测散射数据与理论散射数据的线性关系；将线性关系应用于实测的大气单颗粒散射数据，得到对应大气单颗粒的理论Mie散射强度；进行非线性反演拟合，得到核壳结构球体单颗粒的光学性质参数。本发明效率高、准确和适用于SPAMS，可广泛应用于大气环境科学领域。

The invention discloses a non-linear inversion method of optical parameters of a single particle of an aerosol core-shell structure based on SPAMS measurement, comprising: using SPAMS to detect PSL spheres with known optical property parameters of different particle sizes, and then obtaining the measured PSL sphere At the same time, according to the Mie scattering theory combined with the geometric parameters of the ellipsoid mirror of SPAMS, the theoretical optical scattering response of the PSL ball measured by SPAMS is obtained; the optical scattering theoretical response of the PSL small ball and the scattering intensity measured by SPAMS Perform linear fitting to obtain the linear relationship between the measured scattering data and the theoretical scattering data; apply the linear relationship to the measured atmospheric single particle scattering data to obtain the theoretical Mie scattering intensity of the corresponding atmospheric single particle; perform nonlinear inversion fitting to obtain Optical property parameters of core-shell spherical single particles. The invention has high efficiency, accuracy and is suitable for SPAMS, and can be widely used in the field of atmospheric environment science.

Description

SPAMS surveys gasoloid core-shell structure particles optical parametric nonlinear inversion

Technical field

The present invention relates to atmospheric environment scientific domain, especially a kind of SPAMS surveys gasoloid nucleocapsid structure spherical particles optical parametric nonlinear inversion.

Background technology

Explanation of nouns:

SPAMS: individual particle aerosol mass spectrometer.

Mie scattering: when particle diameter is close with optical wavelength, the scattering of particle to light is called Mie scattering, and Mie scattering theory is the classic algorithm solving spherical scatterer and electromagnetic wave field interaction analytic solution.

PSL:polystyrenelatex, polystyrene latex standard small spherical particles.

For the Disciplinary Frontiers that aerocolloidal research is in atmospheric environment science always, play an important role in many geophysicses and geochemical whole world change process, its research has become one of focus of atmospheric science and even earth environment scientific research.

Traditional mass spectrometer is analyzed mainly for all particles, and SPAMS mainly analyzes the particle diameter and chemical composition information that obtain single particle, and this is significant for the amblent air temperature effect more in depth studying particle.Instrument similar in the world also has ATOFMS (aerosoltime-of-flightmassspectrometer, single-particle aerosol), and ATOFMS is also a kind of individual particle analytical technique of mass spectrum.The people such as Prather have carried out function to ATOFMS and have widened, and are analyzed the effective density and these two primary optical properties parameters of refractive index that obtain particle by a kind of pure algorithm (simplexalgorithm) based on linear programming problem numerical solution.But this pure algorithm is linear algorithm, high to the degree of dependence of initial value, easily cause because the initial value of given calculating is inaccurate Inversion Calculation process to be difficult to restrain or be absorbed in the situation of local extremum, reduce work efficiency and the parameter accuracy rate of analysis.Meanwhile, this algorithm mainly for ATOFMS, and is not suitable for SPAMS (geometric parameter because of SPAMS has with the geometric parameter of ATOFMS variant).

Also do not have no the report for carrying out the work of correlation parameter non-linear inversion based on SPAMS actual measurement atmospheric aerosol nucleocapsid structure spheroid small particle detection at present.

Summary of the invention

In order to solve the problems of the technologies described above, the object of the invention is: propose that a kind of efficiency is high, accurately and be applicable to SPAMS, SPAMS surveys the optical parametric nonlinear inversion of gasoloid nucleocapsid structure spherical particles.

The technical solution adopted for the present invention to solve the technical problems is:

SPAMS surveys the optical parametric nonlinear inversion of gasoloid nucleocapsid structure spheroid individual particle, comprising:

A, employing SPAMS detect the known PSL bead of different-grain diameter Optical property parameters, then draw the scattering strength of actual measurement PSL bead by getting average; Meanwhile, according to the nucleocapsid structure spheroid Single pellet model of Mie scattering theory, the ellipsoidal reflector geometric parameter in conjunction with SPAMS draw SPAMS survey the optical scattering theoretical response of PSL bead;

B, by SPAMS survey the optical scattering theoretical response of PSL bead and SPAMS and survey the scattering strength obtained and carry out linear fit, thus obtain the linear relationship of surveying scattering data and theoretical scattering data;

C, the linear relationship obtained is applied to the air individual particle scattering data of SPAMS actual measurement, thus the theoretical scattering strength of the Mie obtaining corresponding air individual particle;

D, employing Mie theory and nucleocapsid structure spheroid Single pellet model, carry out non-linear inversion matching to the theoretical scattering strength of the Mie of actual measurement airborne particulate, thus obtain the Optical property parameters of Atmospheric particulates.

Further, the PSL bead optical scattering theoretical response R of SPAMS is entered described in_sPAMSexpression formula be:

Wherein, R_aSaxisymmetric scattering response, R_oAthe scattering response of off-axis, S₁and S₂be the scattering amplitude entry of a matrix element obtained by Mie theory calculate, φ is the position angle of plane of polarization, and θ is polar angle, φ_hiand φ_lorespectively to the bound numerical value of angle φ integration, θ_hiand θ_lorespectively to the bound numerical value of angle θ integration, χ is the angle of ellipsoidal reflector aperture and plane of polarization, β and η is maximum polar angle and the position angle of the part scattered light do not collected by spheroid respectively, and n is natural number, function expression when representing the n-th step, π₀=0, π₁=1, π₂=3cos θ, τ₀=0, τ₁=1, τ₂=3cos (2 θ), m_cand m_sbe the core for particle and shell part complex index of refraction respectively, x=ka and y=kb is core for particle and shell part size parameter respectively, a and b is core for particle and shell part sphere radius respectively, and k=2 π/λ is wave number, and λ is surrounding medium wavelength, ψ_nand ξ_nthe Li Kati-Bessel's function of the n-th step,the ball Hankel function of the n-th step, j_n(x) and y_nx () is the spheric Bessel function of the n-th step.

Further, the expression formula of the linear relationship of the actual measurement scattering data that obtains of described step B and theoretical scattering data is:

R_SPAMS,means＝R_meansG+R₀，

Wherein, G and R₀linear fit slope of a curve and intercept respectively, R_meansfor SPAMS surveys the mean value of scattering response, R_{sPAMS, means}survey by SPAMS the mean value of the optical scattering theoretical response of PSL bead.

Further, the Optical property parameters of described particle comprises refractive index and density parameter.

Further, described step D, it comprises:

The roughly interval of D1, the refractive index m setting core and shell respectively and effective density parametrical nonlinearity inverting change, and geometric parameter that is theoretical according to Mie and SPAMS calculates the optical scattering theoretical response R of SPAMS_sPAMS;

The optical scattering theoretical response of partial scattering cross sections data corresponding for individual particle aerodynamic diameter and calculating is carried out parametrical nonlinearity reverse simulation, thus is obtained optimum refractive index and effective density parameter by D2, employing advantest method.

Further, described step D2, it is specially:

The optical scattering theoretical response of partial scattering cross sections data corresponding for individual particle aerodynamic diameter and calculating is carried out parametrical nonlinearity reverse simulation, and constantly adjusts nucleocapsid refractive index m and effective density parameter, until the scattering cross-section data R under actual measurement_{sPAMS, test}with the data R of theory calculate_{sPAMS, means}error minimum till, thus obtain optimum refractive index and effective density parameter.

Further, the expression formula of objective function SqErr that described step D2 adopts when adopting advantest method to carry out parametrical nonlinearity reverse simulation is:

$\mathrm{SqErr}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{\left[\frac{R_{\mathrm{SPAMS},\mathrm{means}}-R_{\mathrm{SPAMS},\mathrm{test}}(m_c,D_{p\_e},m_{s1},D_{p\_s})}{{\mathrm{\σ}}_{\mathrm{mean}}}\right]}^2$

Wherein, N is the length of image data,the standard deviation of the light scattering signal of N bar image data record, D_{p_c}and D_{p_s}core and the shell section diameter of particle respectively, m_cand m_sthe core for particle and shell part complex index of refraction respectively.

Further, described non-linear advantest method is genetic algorithm, and the implementation procedure of described genetic algorithm comprises:

S1, carry out parameter coding according to model parameter collection;

S2, according to coding result generate initial population;

S3, from initial population, select old colony;

S4, the fitness of old colony carried out to assessment and detect;

S5, the result detected according to assessment are carried out defect individual selection, individual to be intersected and individual variation, thus produce new colony;

S6, judge that whether new colony meets the condition of convergence preset, if so, then flow process terminates, otherwise, then replace old colony with new colony, then return step S4.

The invention has the beneficial effects as follows: while the particle diameter of single particle and chemical composition are measured, utilize MIE theoretical, propose a kind of optimized non-linear inversion computing method that better can be applicable to SPAMS apparatus measures parameter, it has the following advantages: (1) surveys the optical scattering response of atmospheric aerosol nucleocapsid structure spherical particles thing in conjunction with Mie theory according to SPAMS, obtain the optical property major parameter of nucleocapsid structure spheroid aerosol particles by micro through parametrical nonlinearity inverting, comprise complex index of refraction and the effective density of core and shell; (2) what adopt when carrying out non-linear inversion the Fitting Calculation is non-linear inversion fitting algorithm, only need set the approximate range of inverted parameters change, without the need to the given initial value of parametric inversion accurately, avoid and cause Optimization inversion to be difficult to restrain or be absorbed in the situation of local extremum because initial value is inaccurate, improve efficiency and the parameter accuracy rate of analytical work; (3) survey the measurement of atmospheric aerosol for SPAMS specially and design.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described.

Fig. 1 the present invention is based on the overall flow figure that SPAMS surveys the optical parametric nonlinear inversion of gasoloid nucleocapsid structure spherical particles thing;

Fig. 2 is the process flow diagram of step D of the present invention;

Fig. 3 is the implementation procedure process flow diagram of genetic algorithm of the present invention;

Fig. 4 is the light scattering geometric graph of axis of symmetry in SPAMS light beam acquisition system of the present invention;

Fig. 5 is off-axis light scattering geometry figure in SPAMS light beam acquisition system of the present invention;

Fig. 6 is that SPAMS of the present invention measures acquisition scattering response and average design sketch to the PSL standard small spherical particles that particle diameter is [0.20.30.50.7211.32] um;

Fig. 7 is the calibration curve schematic diagram that PSL standard particle that the embodiment of the present invention two is 1.59 by refractive index obtains;

Fig. 8 is that SPAMS of the present invention is to SC-EC particle actual measurement response and average design sketch;

Fig. 9 is that the present invention carries out the design sketch of optical parametric non-linear inversion to SC-EC particle actual measurement response average;

Embodiment

Survey the optical parametric nonlinear inversion of gasoloid nucleocapsid structure spheroid individual particle with reference to Fig. 1, SPAMS, comprising:

A, employing SPAMS detect the known PSL bead of different-grain diameter Optical property parameters, then draw the scattering strength of actual measurement PSL bead by getting average; Meanwhile, according to the nucleocapsid structure spheroid Single pellet model of Mie scattering theory, the ellipsoidal reflector geometric parameter in conjunction with SPAMS draw SPAMS survey the optical scattering theoretical response of PSL bead;

B, by SPAMS survey the optical scattering theoretical response of PSL bead and SPAMS and survey the scattering strength obtained and carry out linear fit, thus obtain the linear relationship of surveying scattering data and theoretical scattering data;

C, the linear relationship obtained is applied to the air individual particle scattering data of SPAMS actual measurement, thus the theoretical scattering strength of the Mie obtaining corresponding air individual particle;

D, employing Mie theory and nucleocapsid structure spheroid Single pellet model, carry out non-linear inversion matching to the theoretical scattering strength of the Mie of actual measurement airborne particulate, thus obtain the Optical property parameters of Atmospheric particulates.

Wherein, PSL bead, for carrying out experimental simulation when Optical property parameters (as density and refractive index) is known to atmospheric scattering process.

The object of carrying out non-linear inversion matching is that the physical characteristics parameter (as particle diameter and size etc.) of particle is converted into Optical property parameters.

Be further used as preferred embodiment, described in enter the PSL bead optical scattering theoretical response R of SPAMS_sPr_sPAMSexpression formula be:

Wherein, R_aSaxisymmetric scattering response, R_oAthe scattering response of off-axis, S₁and S₂be the scattering amplitude entry of a matrix element obtained by Mie theory calculate, φ is the position angle of plane of polarization, and θ is polar angle, φ_hiand φ_lorespectively to the bound numerical value of angle φ integration, θ_hiand θ_lorespectively to the bound numerical value of angle θ integration, χ is the angle of ellipsoidal reflector aperture and plane of polarization, β and η is maximum polar angle and the position angle of the part scattered light do not collected by spheroid respectively, and n is natural number, function expression when representing the n-th step, π₀=0, π₁=1, π₂=3cos θ, τ₀=0, τ₁=1, τ₂=3cos (2 θ), m_cand m_sbe the core for particle and shell part complex index of refraction respectively, x=ka and y=kb is core for particle and shell part size parameter respectively, a and b is core for particle and shell part sphere radius respectively, and k=2 π/λ is wave number, and λ is surrounding medium wavelength, ψ_nand ξ_nthe Li Kati-Bessel's function of the n-th step,the ball Hankel function of the n-th step, j_n(x) and y_nx () is the spheric Bessel function of the n-th step.

Be further used as preferred embodiment, the expression formula of the actual measurement scattering data that described step B obtains and the linear relationship of theoretical scattering data is:

R_SPAMS,means＝R_meansG+R₀，

Wherein, G and R₀linear fit slope of a curve and intercept respectively, R_meansfor SPAMS surveys the mean value of scattering response, R_{sPAMS, means}for;

Be further used as preferred embodiment, the Optical property parameters of described particle comprises refractive index and density parameter.

With reference to Fig. 2, be further used as preferred embodiment, described step D, it comprises:

The roughly interval of D1, the refractive index m setting core and shell respectively and effective density parametrical nonlinearity inverting change, and geometric parameter that is theoretical according to Mie and SPAMS calculates the optical scattering theoretical response R of SPAMS_sPAMS;

The optical scattering theoretical response of partial scattering cross sections data corresponding for individual particle aerodynamic diameter and calculating is carried out parametrical nonlinearity reverse simulation, thus is obtained optimum refractive index and effective density parameter by D2, employing advantest method.

Be further used as preferred embodiment, described step D2, it is specially:

The optical scattering theoretical response of partial scattering cross sections data corresponding for individual particle aerodynamic diameter and calculating is carried out parametrical nonlinearity reverse simulation, and constantly adjusts refractive index m and effective density parameter, until the scattering cross-section data R under actual measurement_{sPAMS, test}with the data R of theory calculate_{sPAMS, means}error minimum till, thus obtain optimum refractive index and effective density parameter.

Be further used as preferred embodiment, the expression formula of the objective function SqErr that described step D2 adopts when adopting advantest method to carry out parametrical nonlinearity reverse simulation is:

$\mathrm{SqErr}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{\left[\frac{R_{\mathrm{SPAMS},\mathrm{means}}-R_{\mathrm{SPAMS},\mathrm{test}}(m_c,D_{p\_e},m_{s1},D_{p\_s})}{{\mathrm{\σ}}_{\mathrm{mean}}}\right]}^2$

Wherein, N is the length of image data,the standard deviation of the light scattering signal of N bar image data record, D_{p_c}and D_{p_s}core and the shell section diameter of particle respectively, m_cand m_sthe core for particle and shell part complex index of refraction respectively.

With reference to Fig. 3, be further used as preferred embodiment: described non-linear advantest method is genetic algorithm, and the implementation procedure of described genetic algorithm comprises:

S1, carry out parameter coding according to model parameter collection;

S2, according to coding result generate initial population;

S3, from initial population, select old colony;

S4, the fitness of old colony carried out to assessment and detect;

S5, the result detected according to assessment are carried out defect individual selection, individual to be intersected and individual variation, thus produce new colony;

S6, judge that whether new colony meets the condition of convergence preset, if so, then flow process terminates, otherwise, then replace old colony with new colony, then return step S4.

Wherein, non-linear advantest method of the present invention adopts Evolution Genetic Algorithm, and it is neither only depend on the non-Heuristic inversion method of a class of target function gradient; Be not again carry out completely in the model space, the traditional Monte Carlo Method of random search thoroughly.The same with simulated annealing, it is a kind of non-linear inversion method of carrying out heuristic search in the model space.The basic thought of genetic algorithm: search for from an one group of initial value representing optimization problem solution, this group solution is called a population, here population by some, formed by the individuality of gene code, wherein each individuality is called chromosome, Different Individual by chromosomal copy, intersect or make a variation generate again new individuality, according to the rule of the survival of the fittest, individuality is also evolved in a generation generation, is finally drawn the individuality of condition optimum by the evolution in some generations.As shown in Figure 3, the basic step of genetic algorithm: 1, parameter coding; 2, initial population is generated; 3, Fitness analysis detects; 4, defect individual is selected; 5, individual intersection; 6, individual variation.

Below in conjunction with Figure of description and specific embodiment, the present invention is described in further detail.

Embodiment one

The gasoloid nucleocapsid structure spheroid individual particle light scattering theory computation process of the present embodiment to SPAMS of the present invention is introduced.

The present invention is according to the optical scattering property of air, utilize Mie scattering theory, in conjunction with the ellipsoidal reflector geometric parameter of SPAMS, analyze nucleocapsid structure spheroid individual particle optical scattering process in mass spectrometer, thus set up corresponding theoretical calculation formula and numerical computation method, and design and write corresponding calculation procedure fast.

Be assumed to be the incident spoke of linear polarization, then the optical scattering response of SPAMS is:

R_SPAMS＝R_AS-R_OA(1)

Because SPAMS can not observe the scattering situation of all scopes, therefore must calculate according to the optical scattering response of the effective angle scope of SPAMS light beam collection minute surface to SPAMS, this integral and calculating process can be divided into 2 parts: calculate axisymmetric scattering response R_aSwith the scattering response R of off-axis_oA.

Wherein, in SPAMS light beam acquisition system, the light scattering geometric graph of axis of symmetry as shown in Figure 4, and OG is the incident axle of laser, and the center line perpendicular with OG is the incident axle of gasoloid.Then axisymmetric scattering response R_aScomputing formula be:

$R_{\mathrm{AS}}=\frac{1}{k^2}{\∫}_{{\mathrm{\φ}}_{\mathrm{lo}}}^{{\mathrm{\φ}}_{\mathrm{hi}}}{\∫}_{{\mathrm{\θ}}_{\mathrm{lo}}}^{{\mathrm{\θ}}_{\mathrm{hi}}}({\left|S_1\right|}^2{\sin }^2\mathrm{\φ}+{\left|S_2\right|}^2{\cos }^2\mathrm{\φ})\sin \mathrm{\θd\θd\φ}---\left(7\right)$

Wherein, k is wave number, and φ is the position angle of polarization plane, and θ is polar angle, S₁and S₂it is the scattering amplitude entry of a matrix element obtained by Mie theory calculate.

$S_1\left(\cos \mathrm{\θ}\right)=\underset{n}{\overset{\∞}{\mathrm{\Σ}}}\frac{2n+1}{n(n+1)}(a_n{\mathrm{\π}}_n+b_n{\mathrm{\τ}}_n)---\left(2\right)$

$S_2\left(\cos \mathrm{\θ}\right)=\underset{n}{\overset{\∞}{\mathrm{\Σ}}}\frac{2n+1}{n(n+1)}(a_n{\mathrm{\τ}}_n+b_n{\mathrm{\π}}_n)---\left(3\right)$

${\mathrm{\π}}_n=\frac{2n-1}{n-1}\cos \mathrm{\θ}\·{\mathrm{\π}}_{n-1}-\frac{n}{n-1}{\mathrm{\π}}_{n-2}---\left(4\right)$

$a_n=\frac{{\mathrm{\μm}}^2{j}_n\left(\mathrm{mx}\right){\left[{\mathrm{xj}}_n\left(x\right)\right]}^{\′}-{\mathrm{\μ}}_1{j}_n\left(x\right){\left[{\mathrm{mxj}}_n\left(\mathrm{mx}\right)\right]}^{\′}}{{\mathrm{\μm}}^2{j}_n\left(\mathrm{mx}\right){\left[{\mathrm{xh}}_n^{\left(1\right)}\left(x\right)\right]}^{\′}-{\mathrm{\μ}}_1{h}_n^{\left(1\right)}\left(x\right){\left[{\mathrm{mxj}}_n\left(\mathrm{mx}\right)\right]}^{\′}}---\left(5\right)$

$b_n=\frac{{\mathrm{\μ}}_1{j}_n\left(x\right){\left[{\mathrm{xh}}_n\left(x\right)\right]}^{\′}-\mathrm{\μ}{j}_n\left(x\right){\left[{\mathrm{mxj}}_n\left(\mathrm{mx}\right)\right]}^{\′}}{{\mathrm{\μ}}_1{j}_n\left(\mathrm{mx}\right){\left[{\mathrm{xh}}_n^{\left(1\right)}\left(x\right)\right]}^{\′}-\mathrm{\μ}{h}_n^{\left(1\right)}\left(x\right){\left[{\mathrm{mxj}}_n\left(\mathrm{mx}\right)\right]}^{\′}}---\left(6\right)$

ψ_n(x)＝xj_n(x)(7)

${\mathrm{\ξ}}_n\left(x\right)={\mathrm{xh}}_n^{\left(1\right)}\left(x\right)---\left(8\right)$

$h_n^{\left(1\right)}\left(x\right)=j_n\left(x\right)+{\mathrm{iy}}_n\left(x\right)---\left(9\right)$

$j_n\left(x\right)={(-x)}^n{\left(\frac{1}{x}\frac{d}{\mathrm{dx}}\right)}^n\frac{\sin x}{x}---\left(10\right)$

$y_n\left(x\right)={(-x)}^n{\left(\frac{1}{x}\frac{d}{\mathrm{dx}}\right)}^n\frac{\cos x}{x}---\left(11\right)$

Complex index of refraction is expressed as m=n+ik.

In SPAMS light beam acquisition system, off-axis light scattering geometry figure then as shown in Figure 5, the scattering response R of off-axis_oAcomputing formula be:

$R_{\mathrm{OA}}=\frac{1}{k^2}{\∫}_{\mathrm{\η}-B_{\mathrm{lo}}}^{\mathrm{\η}+\mathrm{\β}}({\left|S_1\right|}^2{\mathrm{\α}}_1+{\left|S_2\right|}^2{\mathrm{\α}}_2)\sin \mathrm{\θd\θ}---\left(12\right)$

${\mathrm{\α}}_1={\∫}_{{\mathrm{\φ}}_{\mathrm{lo}}}^{{\mathrm{\φ}}_{\mathrm{hi}}}{\sin }^2\mathrm{\φd\φ}---\left(13\right)$

${\mathrm{\α}}_2={\∫}_{{\mathrm{\φ}}_{\mathrm{lo}}}^{{\mathrm{\φ}}_{\mathrm{hi}}}{\cos }^2\mathrm{\φd\φ}---\left(14\right)$

φ_hi＝χ-∠DAC(θ)(15)

φ_lo＝χ+∠DAC(θ)(16)

$\∠\mathrm{DAC}\left(\mathrm{\θ}\right)={\cos }^{-1}\left(\frac{\cos \mathrm{\β}-\cos \mathrm{\β}\cos \mathrm{\η}}{\sin \mathrm{\θ}\sin \mathrm{\η}}\right)---\left(17\right)$

Embodiment two

The present embodiment is introduced this process of linear relationship that the present invention obtains actual measurement scattering data and theoretical scattering data by linear fit.

In order to the optical scattering theoretical response and fieldwork that compare SPAMS respond, need the relation function deriving actual measurement and theoretical optics scattering data.Because photomultiplier runs and A/D converter is quantification, therefore R in the range of linearity_meanspulsating sphere and theoretical response present linear relationship.Therefore can obtain R from the linear fit of surveying pulse and theoretical response_meanschange into R_{sPAMS, means}functional expression so as directly and theoretical response compare.Wherein, the linear relationship expression formula of the actual measurement scattering data that obtains of linear fit and theoretical scattering data is:

R_SPAMS,means＝R_meansG+R₀(18)

In order to produce the linear relation of experience, the present invention first uses SPAMS to gather the PSL standard small spherical particles data of different-grain diameter size.Fig. 6 is that SPAMS measures acquisition scattering response and average design sketch to the PSL standard small spherical particles that particle diameter is [0.20.30.50.7211.32] um.Then, in conjunction with refractive index 1.59 and the grain size of PSL standard particle, according to Mie theoretical calculation formula (18), calibration curve is as shown in Figure 7 obtained:

Embodiment three

The present embodiment is introduced the optical physics character of particle and particle diameter and chemical composition relation.

The present invention utilizes the individual particle aerosol mass spectrometer of expansion, carry out laboratory simulation and field inspection obtains theory and measured data respectively, then the optical property data of individual particle are analyzed, thus draw the optical physics character of nucleocapsid structure spheroid individual particle and particle diameter and chemical composition relation.

All actual measurement collecting samples all adopt above-mentioned calibration steps, convert impulse response to scattering cross-section, then carry out matching with theoretical response.

Nonlinearity in parameters reverse simulation process is the minimum value process using optimization method to ask for error function SqErr.Wherein, the expression formula of SqErr is:

$\mathrm{SqErr}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{\left[\frac{R_{\mathrm{SPAMS},\mathrm{means}}-R_{\mathrm{SPAMS},\mathrm{test}}(m_c,D_{p\_e},m_{s1},D_{p\_s})}{{\mathrm{\σ}}_{\mathrm{mean}}}\right]}^2$

Wherein, N is the length of image data,the standard deviation of the light scattering signal of N bar image data record, D_{p_c}and D_{p_s}core and the shell section diameter of particle respectively, m_cand m_sthe core for particle and shell part complex index of refraction respectively, can by different R_{sPAMS, test}value calculates, and concrete calculation process is as follows:

(1) SPAMS is used to gather partial scattering cross sections corresponding to different individual particle aerodynamic diameter respectively;

(2) for consideration nucleocapsid structure spheroid individual particle situation, given particle optical parametric (comprising: negative index and effective density) changes probable ranges, calculates the optical scattering theoretical response of SPAMS according to Mie theory and SPAMS geometric parameter.

(3) result of partial scattering cross sections data corresponding for the individual particle aerodynamic diameter of step (1) and step (2) theory calculate is compared, and constantly particle optical parametric is rolled in adjustment, until the R under actual measurement_{sPAMS, means}with the R of theory calculate_{sPAMS, test}fitting degree arrives the degree (even if error function SqErr is minimum) preset, thus obtains the result of optimized non-linear inversion.

More than that better enforcement of the present invention is illustrated, but the invention is not limited to described embodiment, those of ordinary skill in the art also can make all equivalent variations or replacement under the prerequisite without prejudice to spirit of the present invention, and these equivalent distortion or replacement are all included in the application's claim limited range.

Claims (7)

Translated fromChinese

1.SPAMS实测气溶胶核壳结构颗粒光学参数非线性反演方法，其特征在于：包括：1. The nonlinear inversion method of optical parameters of aerosol core-shell particles measured by SPAMS is characterized in that it includes:A、采用SPAMS检测不同粒径光学性质参数已知的PSL小球，然后通过取均值得出实测PSL小球的散射强度；同时，根据Mie散射理论的核壳结构球体单颗粒模型，结合SPAMS的椭球反射镜几何参数得出SPAMS所测PSL小球的光学散射理论响应；A. Use SPAMS to detect PSL beads with known optical property parameters of different particle sizes, and then obtain the scattering intensity of the measured PSL beads by taking the mean value; at the same time, according to the core-shell structure sphere single particle model of Mie scattering theory, combined with SPAMS The geometric parameters of the ellipsoid reflector are used to obtain the theoretical response of the optical scattering of the PSL ball measured by SPAMS;B、将SPAMS所测PSL小球的光学散射理论响应和SPAMS实测得到的散射强度进行线性拟合，从而得到实测散射数据与理论散射数据的线性关系；B. Perform linear fitting between the theoretical optical scattering response of the PSL balls measured by SPAMS and the scattering intensity measured by SPAMS, so as to obtain the linear relationship between the measured scattering data and the theoretical scattering data;C、将得到的线性关系应用于SPAMS实测的大气单颗粒散射数据，从而得到对应大气单颗粒的Mie理论散射强度；C. Apply the obtained linear relationship to the atmospheric single particle scattering data measured by SPAMS, so as to obtain the Mie theoretical scattering intensity of the corresponding atmospheric single particle;D、采用Mie理论和核壳结构球体单颗粒模型,对实测大气颗粒的Mie理论散射强度进行非线性反演拟合，从而得到大气颗粒物的光学性质参数；D. Using the Mie theory and the single-particle model of the core-shell structure, the nonlinear inversion and fitting of the Mie theoretical scattering intensity of the measured atmospheric particles is carried out, so as to obtain the optical property parameters of the atmospheric particles;所述SPAMS所测PSL小球的核壳结构球体单颗粒光学散射理论响应R_SPAMS的表达式为：The expression of the theoretical response R_SPAMS of the core-shell structure sphere single particle optical scattering of the PSL pellet measured by the SPAMS is:其中，R_AS是轴对称的散射响应，R_OA是偏轴的散射响应，S₁和S₂是由Mie理论计算得到的散射振幅矩阵的元素，φ是偏振面的方位角，θ是极角，φ_hi和φ_lo分别对角度φ积分的上下限数值，θ_hi和θ_lo分别对角度θ积分的上下限数值，χ是椭球反射镜孔径与偏振面的夹角，β和η分别是未被椭球体收集到的那部分散射光的最大极角和方位角，n为自然数，表示第n步时函数表达式，π₀＝0，π₁＝1，π₂＝3cosθ，τ₀＝0，τ₁＝1，τ₂＝3cos(2θ)，m_c和m_s分别是为颗粒物的核和壳部分复折射率，x＝ka和y＝kb分别是为颗粒物的核和壳部分大小参数，a和b分别是为颗粒物的核和壳部分球体半径，k＝2π/λ是波数，λ是环境介质波长，ψ_n和ξ_n是第n步的黎卡提-贝塞尔函数，是第n步的球汉克尔函数，j_n(x)和y_n(x)是第n步的球贝塞尔函数。where R_AS is the axisymmetric scattering response, R_OA is the off_- axis scattering response, S1 and_S2 are the elements of the scattering amplitude matrix calculated by Mie theory, φ is the azimuth angle of the polarization plane, and θ is the polar angle , φ_hi and φ_lo are the upper and lower limit values of the angle φ integration respectively, θ_hi and θ_lo are the upper and lower limit values of the angle θ integration respectively, χ is the angle between the aperture of the ellipsoid mirror and the polarization plane, β and η are respectively The maximum polar angle and azimuth angle of the part of the scattered light not collected by the ellipsoid, n is a natural number, representing the function expression at the nth step, π₀ =0, π₁ =1, π₂ =3cosθ, τ₀ = 0, τ₁ = 1, τ₂ = 3cos(2θ), m_c and m_s are the complex refractive indices of the core and shell of the particle respectively, x=ka and y=kb are the sizes of the core and shell of the particle respectively Parameters, a and b are respectively the core and shell radius of the particle, k=2π/λ is the wave number, λ is the wavelength of the ambient medium, ψ_n and ξ_n are the Riccati-Bessel functions of the nth step, is the spherical Hankel function at step n, and j_n (x) and y_n (x) are spherical Bessel functions at step n.2.根据权利要求1所述的SPAMS实测气溶胶核壳结构颗粒光学参数非线性反演方法，其特征在于：所述步骤B得到的实测散射数据与理论散射数据的线性关系的表达式为：2. the SPAMS measured aerosol core-shell structure particle optical parameter nonlinear inversion method according to claim 1, is characterized in that: the expression of the linear relation of the measured scattering data that described step B obtains and theoretical scattering data is:R_SPAMS,means＝R_meansG+R₀，R_SPAMS,means =R_means G+R₀ ,其中，G和R₀分别是线性拟合曲线的斜率和截距，R_means为SPAMS实测散射响应的平均值，R_SPAMS,means为SPAMS所测PSL小球的光学散射理论响应的平均值。Among them, G and R₀ are the slope and intercept of the linear fitting curve, respectively, R_means is the mean value of the scattering response measured by SPAMS, and R_SPAMS,means is the mean value of the optical scattering theoretical response of the PSL pellets measured by SPAMS.3.根据权利要求2所述的SPAMS实测气溶胶核壳结构颗粒光学参数非线性反演方法，其特征在于：所述颗粒物的光学性质参数包括折射率和密度参数。3. The nonlinear inversion method for optical parameters of aerosol core-shell particles measured by SPAMS according to claim 2, characterized in that: the optical property parameters of the particles include refractive index and density parameters.4.根据权利要求3所述的SPAMS实测气溶胶核壳结构颗粒光学参数非线性反演方法，其特征在于：所述步骤D，其包括：4. The SPAMS measured aerosol core-shell structure particle optical parameter nonlinear inversion method according to claim 3, characterized in that: said step D comprises:D1、分别设定核和壳的折射率m和有效密度参数非线性反演变化的大致区间，并根据Mie理论和SPAMS的几何参数计算SPAMS的光学散射理论响应RSPAMS；D1. Respectively set the refractive index m of the core and the shell and the approximate range of the nonlinear inversion of the effective density parameter, and calculate the optical scattering theoretical response RSPAMS of the SPAMS according to the Mie theory and the geometric parameters of the SPAMS;D2、采用最优法将单颗粒空气动力学直径对应的分波散射截面数据与计算的光学散射理论响应进行参数非线性反演拟合，从而获得最优的折射率和有效密度参数。D2. Use the optimal method to perform parameter nonlinear inversion fitting of the partial wave scattering cross-section data corresponding to the aerodynamic diameter of the single particle and the calculated optical scattering theoretical response, so as to obtain the optimal refractive index and effective density parameters.5.根据权利要求4所述的SPAMS实测气溶胶核壳结构颗粒光学参数非线性反演方法，其特征在于：所述步骤D2，其具体为：5. The SPAMS measured aerosol core-shell structure particle optical parameter nonlinear inversion method according to claim 4, characterized in that: the step D2 is specifically:将单颗粒空气动力学直径对应的分波散射截面数据与计算的光学散射理论响应进行参数非线性反演拟合，并不断调整折射率m和有效密度参数，直到在实测下的散射截面数据R_SPAMS,test与理论计算的数据R_SPAMS,means的误差最小为止，从而获得最优的折射率和有效密度参数。The partial-wave scattering cross-section data corresponding to the aerodynamic diameter of a single particle and the calculated optical scattering theoretical response are used for parameter nonlinear inversion fitting, and the refractive index m and effective density parameters are continuously adjusted until the measured scattering cross-section data R The_{error between SPAMS,test} and the theoretically calculated data R_SPAMS,means is the smallest, so as to obtain the optimal refractive index and effective density parameters.6.根据权利要求5所述的SPAMS实测气溶胶核壳结构颗粒光学参数非线性反演方法，其特征在于：所述步骤D2在采用最优法进行参数非线性反演拟合时所采用的目标函数SqErr的表达式为：6. The SPAMS measured aerosol core-shell particle optical parameter nonlinear inversion method according to claim 5, characterized in that: said step D2 adopts the optimal method for parameter nonlinear inversion fitting The expression of the objective function SqErr is:$\mathrm{<span><span>S</span>S</span>}\mathrm{<span><span>q</span>q</span>}\mathrm{<span><span>E</span>E.</span>}\mathrm{<span><span>r</span>r</span>}\mathrm{<span><span>r</span>r</span>}<span><span>=</span>=</span>\underset{\mathrm{<span><span>j</span>j</span>}<span><span>=</span>=</span>\mathrm{<span><span>1</span>1</span>}}{\overset{\mathrm{<span><span>N</span>N</span>}}{<span><span>\&Sigma;</span>\&Sigma;</span>}}{<span><span>\&lsqb;</span>\&lsqb;</span>\frac{{\mathrm{<span><span>R</span>R</span>}}_{\mathrm{<span><span>S</span>S</span>}\mathrm{<span><span>P</span>P</span>}\mathrm{<span><span>A</span>A</span>}\mathrm{<span><span>M</span>m</span>}\mathrm{<span><span>S</span>S</span>}<span><span>,</span>,</span>\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>e</span>e</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>n</span>no</span>}\mathrm{<span><span>s</span>the\; s</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>R</span>R</span>}}_{\mathrm{<span><span>S</span>S</span>}\mathrm{<span><span>P</span>P</span>}\mathrm{<span><span>A</span>A</span>}\mathrm{<span><span>M</span>m</span>}\mathrm{<span><span>S</span>S</span>}<span><span>,</span>,</span>\mathrm{<span><span>t</span>t</span>}\mathrm{<span><span>e</span>e</span>}\mathrm{<span><span>s</span>the\; s</span>}\mathrm{<span><span>t</span>t</span>}}<span><span>(</span>(</span>{\mathrm{<span><span>m</span>m</span>}}_{\mathrm{<span><span>c</span>c</span>}}<span><span>,</span>,</span>{\mathrm{<span><span>D</span>D.</span>}}_{\mathrm{<span><span>p</span>p</span>}<span><span>\_</span>\_</span>\mathrm{<span><span>e</span>e</span>}}<span><span>,</span>,</span>{\mathrm{<span><span>m</span>m</span>}}_{\mathrm{<span><span>s</span>the\; s</span>}\mathrm{<span><span>1</span>1</span>}}<span><span>,</span>,</span>{\mathrm{<span><span>D</span>D.</span>}}_{\mathrm{<span><span>p</span>p</span>}<span><span>\_</span>\_</span>\mathrm{<span><span>s</span>the\; s</span>}}<span><span>)</span>)</span>}{{\mathrm{<span><span>\&sigma;</span>\&sigma;</span>}}_{\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>e</span>e</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>n</span>no</span>}}}<span><span>\&rsqb;</span>\&rsqb;</span>}^{\mathrm{<span><span>2</span>2</span>}}$其中，N为采集数据的长度，是N条采集数据记录的光散射信号的标准差，Dp_e和D_{p_s}分别是颗粒物的核和壳部分直径，m_c和m_sl分别是为颗粒物的核和壳部分复折射率。Among them, N is the length of the collected data, is the standard deviation of the light scattering signals of N pieces of collected data records, Dp_e and D_{p_s} are the diameters of the core and shell parts of the particles, respectively, m_c and m_sl are the complex refractive indices of the core and shell parts of the particles, respectively.7.根据权利要求6所述的SPAMS实测气溶胶核壳结构颗粒光学参数非线性反演方法，其特征在于：所述非线性最优法为遗传学算法，所述遗传学算法的实现过程包括：7. The SPAMS measured aerosol core-shell particle optical parameter nonlinear inversion method according to claim 6, characterized in that: the nonlinear optimal method is a genetic algorithm, and the implementation process of the genetic algorithm includes :S1、根据模型参数集进行参数编码；S1. Perform parameter encoding according to the model parameter set;S2、根据编码的结果生成初始群体；S2. Generate an initial group according to the encoding result;S3、从初始群体中选出旧群体；S3. Select the old group from the initial group;S4、对旧群体的适应度进行评估检测；S4. Evaluate and detect the fitness of the old group;S5、根据评估检测的结果进行优良个体选择、个体交叉和个体变异，从而产生新群体；S5. Perform excellent individual selection, individual crossover and individual variation according to the results of the evaluation and detection, thereby generating new groups;S6、判断新群体是否满足预设的收敛条件，若是，则流程结束，反之，则以新群体代替旧群体，然后返回步骤S4。S6. Determine whether the new group satisfies the preset convergence condition. If yes, the process ends. Otherwise, replace the old group with the new group, and then return to step S4.