Simulation and Testing of the Radiation Performance of SiC Particles with Different Distribution Morphologies
Round 1
Reviewer 1 Report
The manuscript is devoted to the simulation of the extinction spectra of SiC clusters, which are of the big interest due to their high wear resistance, superior high temperature mechanical properties and low cost. The authors study agglomeration of SiC particles into clusters, and perform calculations of the phase function and extinction cross sections in accordance with generalized multiparticle Mie-solution. Experimental extinction spectra of the samples with SiC particles are also presented and compared with the simulation.
I regret to say, that this paper lacks understanding of the physical nature of the phenomena under study, contains incorrect or unproven conclusions, and, despite the importance of the topic, I can not recommend this manuscript for publication.
In the title it is said that the study is performed for the nanoparticles “with different distribution morphology”, but what I see in simulation, only the size of the clusters but not morphology changes. Figure 1 confirms that the particles in the clusters of different size are centered, and no difference in morphology is observed. Figures 8 and 9 present SEM images at different scales (10000 for Fig.8 and 2000 for Fig.9), it is difficult to conclude on the morphology on the base of these pictures.
In discussion of the simulation results, the authors ignore the fact that in the study of optical phenomena, the relations between the object under study and the wavelength plays a crucial role. When they say “for wavelength larger than 10 microns”, or “for large particle sizes” they do not pay attention to the relation between the size of the particles and the wavelength. But if they change the spectral range, the results may be different.
In Discussion section, Figures 13 and 15 the authors compare the simulation for “SiC elementary particles”, presented in Figure 4a, with the experimental spectra for agglomeration of particles. If finally the authors use a single particle model, what was the reason of using GMM theory in simulation? This calls into question the meaning of the calculations.
The general idea of the calculations performed is unclear. The authors pay a lot of attention to the phase function of the extinction, but finally, they do not present any experiments that could confirm their results. The paper presents very little experimental data, and the one presented is not in a good coincidence with the simulation. It is difficult to call the experiment and simulation in Figure 13 a good match.
I also have a few less general comments which may help the authors improve their future papers.
In section 3.1.1, which method was used for simulation, Mie theory or GMM model? It looks like GMM model is useless for this case, for Mie theory gives an analytical solution for a single particle. The authors should clarify this issue.
Line 179: “The phase function fluctuates at all wavelengths with d=38μm.” What are the physical reasons for this?
Line 184: “Figure 3 shows that when λ<10μm, the particle size has little effect on the scattering directivity of SiC particles.” I do believe that here not the particle size itself, but the relation between the particle size and the wavelength plays role. And this is proved by Figure 3, where for the wavelength of 1 micron (Fig.3a) the phase function of nanoparticles with d=0,1 and d=1,5 microns demonstrates angle dependence. However, as the wavelength increases, the difference between the phase function of nanoparticles with d=0,1 and d=1,5 microns almost vanishes (Fig.3c,d). So, the conclusions made by the authors are incorrect.
In discussion on Figure 4, how do the authors explain the minimum in the scattering factor of particles at a wavelength of 10μm, which presents for all particle sizes?
Figure 5 again demonstrates that when the wavelength exceeds the cluster size, the behavior of the phase function changes, but the authors ignore this fact in the discussion.
Line 220, “Figure 6 shows that the larger the SiC cluster particles are, the greater the forward scattering is and the smaller the backscattering is, but it is small.” This statement contradicts Figure 6e, where for all wavelengths the phase function is symmetric, and the forward scattering is the same as the backscattering.
In Figures 10 and 11, do the authors mean cluster size instead of particle size? From Section 3.2 it follows that all the particles were 100 nm in size.
In Figure 12, the only difference in the two spectra is the peak at 12,8 microns. The authors state this fact, but do not give any explanation.
I also have some minor notes. 1) The scale and legend for Figures 2-7 are difficult to read. 2) Mie scattering theory (line 96) and GMM theory (line 119) require a reference.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The exploration of radiation properties of SiC nanoparticles is of great importance for scientific community of photonics and thermal radiation. The authors combine the theoretical simulations and ATR-FTIR experiments to investigate the influence of different distribution of states on thermal radiative properties of SiC nanoparticles. The topic is very interesting and the presented results are good. Thus, I recommend the publication of this paper in the journal of Photonics.
Yet, there are some minor issues that should be solved.
- For those terms like XRD, TEM, DDA and GMM, their full name should be firstly given.
- The fonts in Figures 2-8 are not clear. And those figures should be enlarged to make it more clear.
- In Figure 1, it seems that the density of SiC clusters does not change as the number of particles enlarges. How can they change the distribution density?
- What’s the spectral resolution of ATR-FTIR measurements?
- How is the temperature effect on the radiation properties?
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The distribution of nanoparticles is very important to their properties, which has attracted more and more researchers in recent years. In this paper, the authors study the effects of different distribution states of semiconductor nanoparticles on their radiation characteristics, based on the Mie scattering theory, Generalized Multiparticle Mie model, fractal theory, and DLA model. The results of this paper are of great significance to obtain ideal optical properties by adjusting the distribution state of particles.
The whole paper, with rigorous structure and smooth logic, has some practical significance and is recommended to be published.
Questions:
- Page 13, line 104. Is scattering cross section ? And and is the scattering function. Please check it. Notice the space between the two words.
- Please give the full name when the abbreviation of the noun first appears in the paper.
- Please give references to the classical theories (such as Mie scattering theory) used in this paper.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors made an essensial improvement to the article, correcting many inaccuracies and elucidating issues that required clarification. I believe the article can be published in the present form.
