InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, ...InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, Fourier transform infrared （PTIR） transmittance measurements and scanning electron microscopy （SEM）. The influence of different growth conditions on the optical and structural properties of the materials was studied. The results revealed that the good crystalline quality, mirror smooth surface and flat interface of InAsSb epilayers were achieved. They benefited from optimized growth conditions, i.e., sufficient homogeneity of the growth melt and a very slow cooling rate.展开更多
This paper demonstrates an intrinsic modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films.The(NiCuCrFeSi)N((NCCFS)N)films were deposited by a magnetron s...This paper demonstrates an intrinsic modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films.The(NiCuCrFeSi)N((NCCFS)N)films were deposited by a magnetron sputtering system.Rutherford backscattering spectroscopy analysis confirms the uniform composition and good homogeneity of these high-entropy films.The real and imaginary parts of the permittivity for the(NCCFS)N material are calculated on the basis of the reflectance spectral fitting results.A redshift cutoff wavelength of the reflectance spectrum with increasing nitrogen gas flow rate exists because of the different levels of dispersion when changing nitrogen content.To realize significant solar absorption,the film surface was reconstituted to match its impedance with air by designing a pyramid nanostructure metasurface.Compared with the absorptance of the as-deposited films,the designed metasurface obtains a significant improvement in solar absorption with the absorptance increasing from 0.74 to 0.99.The metasurfaces also show low mid-infrared emissions with thermal emittance that can be as low as 0.06.These results demonstrate a new idea in the design of solar selective absorbing surface with controllable absorptance and low infrared emission for high-efficiency photo-thermal conversion.展开更多
Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of ...Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.展开更多
基金provided by the National Natural Science Foundation of China (No. 60777022)the Program for Young Excellent Tal-ents in Tongji University
文摘InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, Fourier transform infrared （PTIR） transmittance measurements and scanning electron microscopy （SEM）. The influence of different growth conditions on the optical and structural properties of the materials was studied. The results revealed that the good crystalline quality, mirror smooth surface and flat interface of InAsSb epilayers were achieved. They benefited from optimized growth conditions, i.e., sufficient homogeneity of the growth melt and a very slow cooling rate.
基金the National Natural Science Foundation of China(Nos.51732001,U1832219,and 51972013)Beijing Natural Science Foundation(No.2182035)+1 种基金the Fundamental Research Funds for the Central Universities,the Program of China Scholarships Council(No.201806020161)the Academic Excellence Foundation of Beihang University(BUAA)for Ph.D.Students.
文摘This paper demonstrates an intrinsic modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films.The(NiCuCrFeSi)N((NCCFS)N)films were deposited by a magnetron sputtering system.Rutherford backscattering spectroscopy analysis confirms the uniform composition and good homogeneity of these high-entropy films.The real and imaginary parts of the permittivity for the(NCCFS)N material are calculated on the basis of the reflectance spectral fitting results.A redshift cutoff wavelength of the reflectance spectrum with increasing nitrogen gas flow rate exists because of the different levels of dispersion when changing nitrogen content.To realize significant solar absorption,the film surface was reconstituted to match its impedance with air by designing a pyramid nanostructure metasurface.Compared with the absorptance of the as-deposited films,the designed metasurface obtains a significant improvement in solar absorption with the absorptance increasing from 0.74 to 0.99.The metasurfaces also show low mid-infrared emissions with thermal emittance that can be as low as 0.06.These results demonstrate a new idea in the design of solar selective absorbing surface with controllable absorptance and low infrared emission for high-efficiency photo-thermal conversion.
基金the support of the National Natural Science Foundation of China(No.61931025)the National Key R&D Program of China(No.2017YFC1405600)。
文摘Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.
