We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the thre...We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.展开更多
In order to choose the appropriate reference surface on the machined surface roughness of Si Cp/Al composites, the cutting experiments of Si Cp/Al composites were carried out, and the machined surface topography was m...In order to choose the appropriate reference surface on the machined surface roughness of Si Cp/Al composites, the cutting experiments of Si Cp/Al composites were carried out, and the machined surface topography was measured by OLS3000 Confocal laser scanning microscope. The 3D measured data of machined surface topography were analyzed by the area power spectrum density. The result shows that the texture of machined surface topography in milling of Si Cp/Al composites is almost isotropic. This is the reason that the values of Rq at different locations on the same machined surface are obviously different. Through the comparison of performance of different filtering methods, the robust least squares reference surface can be used to extract the surface roughness of SiC p/Al composites effectively.展开更多
The TiN, TiAlN, and TiAlSiN coatings were prepared on YT14 cutting tool surface with CAIP(cathode arc ion plating), the surface morphologies and phases were analyzed with FESEM(field emission scanning electron micr...The TiN, TiAlN, and TiAlSiN coatings were prepared on YT14 cutting tool surface with CAIP(cathode arc ion plating), the surface morphologies and phases were analyzed with FESEM(field emission scanning electron microscopy), and XRD(X-ray diffraction), respectively, and the coating parameters such as 3D surface micro-topography, grain size, surface height, hierarchy, profile height, and power spectral density, etc, were measured with AFM(atomic force microscope). The results show that the phases of TiN, TiAlN, and TiAlSiN coatings are TiN, TiN+TiAlN, TiN+Si_3N_4+TiAlN, respectively, while the surface roughness Sa of TiN, TiAlN, and TiAlSiN coatings is 75.3, 98.9, and 42.1 nm, respectively, and the roughness depth Sk is 209, 389, and 54 nm, respectively, the sequence of average grain sizes is TiAlN〉TiN〉TiAlSiN. The surface bearing index Sbi of TiN, TiAlN, and TiAlSiN coatings is 0.884, 1.01, and 0.37, respectively, and the sequence of surface bearing capability is TiAlN〉TiN〉TiAlSiN. At the lower wavelength(102-103 nm), the power spectral densities have a certain correlation, and the sequence of TiN〉TiAlN〉TiAlSiN, while the correlation is low at the higher wavelength(〉103 nm).展开更多
A method of detecting dry, icy and wet road surface conditions based on scanniag detection of single wavelength backward power is proposed in this letter. The detector is used to receive the backward scattered power w...A method of detecting dry, icy and wet road surface conditions based on scanniag detection of single wavelength backward power is proposed in this letter. The detector is used to receive the backward scattered power which changes with the incidence angle. The relationship between backward power and incidence angle is used to find out the effective angle range and distinguish method. Experiment and simulation show that it is feasible to classifv these three conditions within incidence angle of 5.3 degree.展开更多
We reported a facile and bio-inspired strategy for obtaining antireflective (AR) coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different mo...We reported a facile and bio-inspired strategy for obtaining antireflective (AR) coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-cross- linking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5% ~ 8%, with an efficiency anti- reflection of 4% ~ 7%; compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4% ~ 8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern. Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB632801 and 2013CB632803the National Natural Science Foundation of China under Grant Nos 61435014,61306058 and 61274094the Beijing Natural Science Foundation under Grant No 4144086
文摘We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.
基金Projects(51305284,61203208) supported by the National Natural Science Foundation of China
文摘In order to choose the appropriate reference surface on the machined surface roughness of Si Cp/Al composites, the cutting experiments of Si Cp/Al composites were carried out, and the machined surface topography was measured by OLS3000 Confocal laser scanning microscope. The 3D measured data of machined surface topography were analyzed by the area power spectrum density. The result shows that the texture of machined surface topography in milling of Si Cp/Al composites is almost isotropic. This is the reason that the values of Rq at different locations on the same machined surface are obviously different. Through the comparison of performance of different filtering methods, the robust least squares reference surface can be used to extract the surface roughness of SiC p/Al composites effectively.
基金Funded by the Jiangsu Province Science and Technology Support Program(Industry)(No.BE2014818)
文摘The TiN, TiAlN, and TiAlSiN coatings were prepared on YT14 cutting tool surface with CAIP(cathode arc ion plating), the surface morphologies and phases were analyzed with FESEM(field emission scanning electron microscopy), and XRD(X-ray diffraction), respectively, and the coating parameters such as 3D surface micro-topography, grain size, surface height, hierarchy, profile height, and power spectral density, etc, were measured with AFM(atomic force microscope). The results show that the phases of TiN, TiAlN, and TiAlSiN coatings are TiN, TiN+TiAlN, TiN+Si_3N_4+TiAlN, respectively, while the surface roughness Sa of TiN, TiAlN, and TiAlSiN coatings is 75.3, 98.9, and 42.1 nm, respectively, and the roughness depth Sk is 209, 389, and 54 nm, respectively, the sequence of average grain sizes is TiAlN〉TiN〉TiAlSiN. The surface bearing index Sbi of TiN, TiAlN, and TiAlSiN coatings is 0.884, 1.01, and 0.37, respectively, and the sequence of surface bearing capability is TiAlN〉TiN〉TiAlSiN. At the lower wavelength(102-103 nm), the power spectral densities have a certain correlation, and the sequence of TiN〉TiAlN〉TiAlSiN, while the correlation is low at the higher wavelength(〉103 nm).
文摘A method of detecting dry, icy and wet road surface conditions based on scanniag detection of single wavelength backward power is proposed in this letter. The detector is used to receive the backward scattered power which changes with the incidence angle. The relationship between backward power and incidence angle is used to find out the effective angle range and distinguish method. Experiment and simulation show that it is feasible to classifv these three conditions within incidence angle of 5.3 degree.
基金the National Natural Science Foundation of China (Nos. 21522403, 51373098)the National Basic Research Program (No. 2013CB834506)+1 种基金Education Commission of Shanghai Municipal Government (No. 15SG13)IFPM 2016B002 of Shanghai Jiao Tong University & Affiliated Sixth People’s Hospital South Campus for their financial support
文摘We reported a facile and bio-inspired strategy for obtaining antireflective (AR) coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-cross- linking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5% ~ 8%, with an efficiency anti- reflection of 4% ~ 7%; compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4% ~ 8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern. Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle