MnO_2/activated carbon composite（Mn-ACC） wave absorber was prepared by the reaction between Mn（CH_3COO）_2 and KMnO_4 on activated carbon. Then, a novel cement based composite absorbing coating（CB-CAC） was prepar...MnO_2/activated carbon composite（Mn-ACC） wave absorber was prepared by the reaction between Mn（CH_3COO）_2 and KMnO_4 on activated carbon. Then, a novel cement based composite absorbing coating（CB-CAC） was prepared by adding the Mn-ACC, manganese zinc ferrite and rubber particles into cement. XRD method was used to analyze the reaction products of the Mn-ACC. The tensile bond strength and the wave absorbing properties of the CB-CACs were also tested. The results showed that the crystallinity of MnO_2 formed in the Mn-ACC was poor. Adding Mn-ACC into the CB-CAC led to first increase and then decrease of the tensile bond strength. The tensile bond strength reached 1.89 MPa with 8.51% of the Mn-ACC. The CB-CACs obtained the optimal absorbing properties with the cement, manganese zinc ferrite, Mn-ACC, rubber particles and H_2O mass ratio of 7.5？7.5？1？1？5.5, respectively. The band width of the reflection below-10 dB was up to 8.8 GHz, which accounted for 57.14% of the test band.展开更多
The paper explores the possibilities of using carbonyl iron in the form of a powder for the manufacture of radar-absorbing paints-reducing the radar signature of the objects that they cover.The attenuation values in t...The paper explores the possibilities of using carbonyl iron in the form of a powder for the manufacture of radar-absorbing paints-reducing the radar signature of the objects that they cover.The attenuation values in the range of 4-18 GHz for various coating thicknesses,ranging from 0.5 to 2.00 mm with 0.5 mm increment,and for different absorber content-75%and 80%,as well as the use of two different binders in the form of epoxy resins with hardeners,were investigated.For the frequency of 18 GHz and a 1.5 mm thick coating with a 75%absorber content,Epidian 112 resin and Saduramid 10/50 hardener used as a binder,and the maximum attenuation level obtained equalled 20.2 d B at 16 GHz.Additionally,the absorber particle size ranging from 3 to 4μm and its higher mass content resulted in achieving the reflection loss above-12 d B in the entire 8-12.5 GHz range for layers between 1-and 1.5 mm thickness.The qualitative assessment of the tested samples in the context of camouflage in the radar range was also performed,using statistical analysis.展开更多
Aerospace structures can be approximately modeled as a combination of canonical structures such as cylinder,cone and ellipsoid.Thus the RCS estimation of such canonical structures is of prime interest.Furthermore meta...Aerospace structures can be approximately modeled as a combination of canonical structures such as cylinder,cone and ellipsoid.Thus the RCS estimation of such canonical structures is of prime interest.Furthermore metamaterials possess peculiar electromagnetic properties which can be useful in modifying the RCS of structures.This paper is aimed at calculating the RCS of an infinitely long PEC circular cylinder coated with one or two layers of metamaterial.The incident and scattered fields of coated cylinder are expressed in terms of series summation of Bessel and Hankel functions.The unknown coefficients of summation are obtained by applying appropriate boundary conditions.The computations are carried out for both principal polarizations.The computed results are validated against the numerical-based method of moments.Further,the variation of RCS of the metamaterial coated PEC cylinder with material parameters,frequency,aspect angle and polarization is analyzed.展开更多
基金Funded by the International Cooperation Office of the Ministry of Science and Technology of China(2013DFR50360)the Postdoctoral Research Foundation of Shenyang Ligong University,the Open Fund from Advanced Processing Technology of Metal Materials of Liaoning Key Laboratory,Shenyang Ligong Universitythe Guide Project from Liaoning Natural Science Foundation of China(No.201602646)
文摘MnO_2/activated carbon composite（Mn-ACC） wave absorber was prepared by the reaction between Mn（CH_3COO）_2 and KMnO_4 on activated carbon. Then, a novel cement based composite absorbing coating（CB-CAC） was prepared by adding the Mn-ACC, manganese zinc ferrite and rubber particles into cement. XRD method was used to analyze the reaction products of the Mn-ACC. The tensile bond strength and the wave absorbing properties of the CB-CACs were also tested. The results showed that the crystallinity of MnO_2 formed in the Mn-ACC was poor. Adding Mn-ACC into the CB-CAC led to first increase and then decrease of the tensile bond strength. The tensile bond strength reached 1.89 MPa with 8.51% of the Mn-ACC. The CB-CACs obtained the optimal absorbing properties with the cement, manganese zinc ferrite, Mn-ACC, rubber particles and H_2O mass ratio of 7.5？7.5？1？1？5.5, respectively. The band width of the reflection below-10 dB was up to 8.8 GHz, which accounted for 57.14% of the test band.
文摘The paper explores the possibilities of using carbonyl iron in the form of a powder for the manufacture of radar-absorbing paints-reducing the radar signature of the objects that they cover.The attenuation values in the range of 4-18 GHz for various coating thicknesses,ranging from 0.5 to 2.00 mm with 0.5 mm increment,and for different absorber content-75%and 80%,as well as the use of two different binders in the form of epoxy resins with hardeners,were investigated.For the frequency of 18 GHz and a 1.5 mm thick coating with a 75%absorber content,Epidian 112 resin and Saduramid 10/50 hardener used as a binder,and the maximum attenuation level obtained equalled 20.2 d B at 16 GHz.Additionally,the absorber particle size ranging from 3 to 4μm and its higher mass content resulted in achieving the reflection loss above-12 d B in the entire 8-12.5 GHz range for layers between 1-and 1.5 mm thickness.The qualitative assessment of the tested samples in the context of camouflage in the radar range was also performed,using statistical analysis.
文摘Aerospace structures can be approximately modeled as a combination of canonical structures such as cylinder,cone and ellipsoid.Thus the RCS estimation of such canonical structures is of prime interest.Furthermore metamaterials possess peculiar electromagnetic properties which can be useful in modifying the RCS of structures.This paper is aimed at calculating the RCS of an infinitely long PEC circular cylinder coated with one or two layers of metamaterial.The incident and scattered fields of coated cylinder are expressed in terms of series summation of Bessel and Hankel functions.The unknown coefficients of summation are obtained by applying appropriate boundary conditions.The computations are carried out for both principal polarizations.The computed results are validated against the numerical-based method of moments.Further,the variation of RCS of the metamaterial coated PEC cylinder with material parameters,frequency,aspect angle and polarization is analyzed.
