TiAIN]Cu nanocomposite coatings with Cu concentration of 0-1.4 at.% were deposited on the high- speed steel （HSS） substrates by filtered cathodic arc ion plating technique. The chemical composition, microstructure, ...TiAIN]Cu nanocomposite coatings with Cu concentration of 0-1.4 at.% were deposited on the high- speed steel （HSS） substrates by filtered cathodic arc ion plating technique. The chemical composition, microstructure, morphology, adhesion strength, mechanical and tribological properties of the TiAIN/Cu coatings were characterized and analyzed. The results reveal that the coating structure and properties depend on not only the Cu concentration, hut also the deposition condition. The addition of Cu significantly decreases the grain size and weakens the texture in the TiAlN/Cu coatings. With increasing the Cu concentration, the coating hardness decreases slightly from 30.7 GPa of the pure TiAlN coating to 28.5 GPa of the TiAlN/Cu coating with 1.4 at,% Cu. All the TiAlN/Cu coatings present sufficient adhesion strength. In addition, the existing state of additive Cu in the TiAlN/Cu coatings is also investigated.展开更多
A1N films were prepared on Si（100） and quartz glass substrates with high deposition rate of 30 nm-min-I at the temperature of below 85 ℃ by the magnetic-filtered cathodic arc ion plating （FCAIP） method. The as-de...A1N films were prepared on Si（100） and quartz glass substrates with high deposition rate of 30 nm-min-I at the temperature of below 85 ℃ by the magnetic-filtered cathodic arc ion plating （FCAIP） method. The as-deposited A1N films show very smooth surface and almost no macrodroplets. The films are in amorphous state, and the formation of A1N is confirmed by Nls and A12p X-ray photoelectron spectroscopy （XPS）. The XPS depth profile analysis shows that oxygen is mainly absorbed on the A1N surface. The A1N film has A1 and N concentrations close to the stoichiometric ratio with a small amount of A1203. The prepared A1N films are highly transparent over the wave- length range of 210-990 nm. The optical transmission spectrum reveals the bandgap of 6.1 eV. The present technique provides a good approach to prepare large-scale A1N films with controlled structure and good optical properties at low temperature.展开更多
A method of digitally high pass filtering in frequency domain is proposed to eliminate the background noise of the decoded image in Fresnel zone plate scanning holography. The high pass filter is designed as a circula...A method of digitally high pass filtering in frequency domain is proposed to eliminate the background noise of the decoded image in Fresnel zone plate scanning holography. The high pass filter is designed as a circular stop, which should be suitable to suppressing the background noise significantly and remain much low frequency information of the object. The principle of high pass filtering is that the Fourier transform of the decoded image is multiplied with the high pass filter. Thus the frequency spectrum of the decoded image without the background noise is achieved. By inverse Fourier transform of the spectrum of the decoded image after multiplying operation, the decoded image without the background noise is obtained. Both of the computer simulations and the experimental results show that the contrast and the signal-to-noise ratio of the decoded image are significantly improved with digital filtering.展开更多
Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important perform...Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important performance parameters. In this paper, an analytically mathematical model of induced charge on a circular thin-plate electrode is first derived. Then the spatial sensitivity and filtering effect of the circular electrostatic sensor are investigated by numerical calculations. Finally,experimental studies are performed to testify the theoretical results. Both theoretical and experimental results demonstrate that circular thin-plate electrostatic sensors act as a low-pass filter in the spatial frequency domain, and both the spatial filtering effect and the temporal frequency response characteristics depend strongly on the spatial position and velocity of the charged particle. These conclusions can provide guidelines for the optimal design of circular thin-plate electrostatic sensors.展开更多
A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated. The filter tunability is achieved by rotating the pol...A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated. The filter tunability is achieved by rotating the polarization controller. The spectral shift is dependent on rotation direction and the position of the polarization controller. In addition, the adjustable range achieved by rotating the half-wave-plate polarization controller is twice higher than that of the quarter-wave-plate one.展开更多
基金supported by the National Key Basic Research Program of China(“973”Program,No.2012CB625100)the Natural Science Foundation of Liaoning Province(No.2013020093)
文摘TiAIN]Cu nanocomposite coatings with Cu concentration of 0-1.4 at.% were deposited on the high- speed steel （HSS） substrates by filtered cathodic arc ion plating technique. The chemical composition, microstructure, morphology, adhesion strength, mechanical and tribological properties of the TiAIN/Cu coatings were characterized and analyzed. The results reveal that the coating structure and properties depend on not only the Cu concentration, hut also the deposition condition. The addition of Cu significantly decreases the grain size and weakens the texture in the TiAlN/Cu coatings. With increasing the Cu concentration, the coating hardness decreases slightly from 30.7 GPa of the pure TiAlN coating to 28.5 GPa of the TiAlN/Cu coating with 1.4 at,% Cu. All the TiAlN/Cu coatings present sufficient adhesion strength. In addition, the existing state of additive Cu in the TiAlN/Cu coatings is also investigated.
基金financially supported by the National Natural Science Foundation of China(Nos.51071070 and 51271079)the Program for New Century Excellent Talents in University(No.NCET-11-0156)the Fundamental Research Funds for the Central Universities,South China University of Technology(No.2012ZZ0015)
文摘A1N films were prepared on Si（100） and quartz glass substrates with high deposition rate of 30 nm-min-I at the temperature of below 85 ℃ by the magnetic-filtered cathodic arc ion plating （FCAIP） method. The as-deposited A1N films show very smooth surface and almost no macrodroplets. The films are in amorphous state, and the formation of A1N is confirmed by Nls and A12p X-ray photoelectron spectroscopy （XPS）. The XPS depth profile analysis shows that oxygen is mainly absorbed on the A1N surface. The A1N film has A1 and N concentrations close to the stoichiometric ratio with a small amount of A1203. The prepared A1N films are highly transparent over the wave- length range of 210-990 nm. The optical transmission spectrum reveals the bandgap of 6.1 eV. The present technique provides a good approach to prepare large-scale A1N films with controlled structure and good optical properties at low temperature.
文摘A method of digitally high pass filtering in frequency domain is proposed to eliminate the background noise of the decoded image in Fresnel zone plate scanning holography. The high pass filter is designed as a circular stop, which should be suitable to suppressing the background noise significantly and remain much low frequency information of the object. The principle of high pass filtering is that the Fourier transform of the decoded image is multiplied with the high pass filter. Thus the frequency spectrum of the decoded image without the background noise is achieved. By inverse Fourier transform of the spectrum of the decoded image after multiplying operation, the decoded image without the background noise is obtained. Both of the computer simulations and the experimental results show that the contrast and the signal-to-noise ratio of the decoded image are significantly improved with digital filtering.
基金supported by the National Natural Science Foundation of China(Nos.51275520,50805142)
文摘Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important performance parameters. In this paper, an analytically mathematical model of induced charge on a circular thin-plate electrode is first derived. Then the spatial sensitivity and filtering effect of the circular electrostatic sensor are investigated by numerical calculations. Finally,experimental studies are performed to testify the theoretical results. Both theoretical and experimental results demonstrate that circular thin-plate electrostatic sensors act as a low-pass filter in the spatial frequency domain, and both the spatial filtering effect and the temporal frequency response characteristics depend strongly on the spatial position and velocity of the charged particle. These conclusions can provide guidelines for the optimal design of circular thin-plate electrostatic sensors.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11274181,10974100,and 10674075)the Tianjin Key Program of Application Foundations and Future Technology Research Project,China (Grant No. 10JCZDJC24300)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120031110033)
文摘A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated. The filter tunability is achieved by rotating the polarization controller. The spectral shift is dependent on rotation direction and the position of the polarization controller. In addition, the adjustable range achieved by rotating the half-wave-plate polarization controller is twice higher than that of the quarter-wave-plate one.
