The data of deformation strength and microstructure of thin films of nanocrystalline Pd recently provided by Colla et al. have been analysed. It is shown that the properties of the films with cylindrical grains of30 n...The data of deformation strength and microstructure of thin films of nanocrystalline Pd recently provided by Colla et al. have been analysed. It is shown that the properties of the films with cylindrical grains of30 nm diameter extending over a significant portion of the film thickness（≈90 nm） are quantitatively comparable to what is known from nanocrystalline bulk material. This is explained in terms of boundarymediated processes governing emission, storage, and recovery of dislocations.展开更多
The non-uniform argon dc glow discharge plasma system has been constructed in a very special design to investigate the effects of variable tube radius on plasma parameters. By using isolated computer controlled three ...The non-uniform argon dc glow discharge plasma system has been constructed in a very special design to investigate the effects of variable tube radius on plasma parameters. By using isolated computer controlled three couples of a double probe （TCDP） system, the electron temperature, electron density, the reduced electric field, and electron drift velocity are measured at low and intermediate pressures. It is shown that the electron temperature and reduced electric field （density） decreases （increases） as the radius decreases, at low discharge current and pressures. For large radius regions, at high discharge currents and pressures, the behaviour of the plasma parameters of specially reduced electric field change similarly to those in a uniform discharge system.展开更多
A novel optical fiber hydrogen sensor based on theπ-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper.The hydrogen sensitive Pd/Hf film with the l...A novel optical fiber hydrogen sensor based on theπ-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper.The hydrogen sensitive Pd/Hf film with the length of 4 mm is successfully deposited in theπ-phase-shifted grating region by the magnetron sputtering process and rotating fixture technology.Since the hydrogen sensitivity between the notch and flank wavelengths of theπ-phase-shifted grating is different due to the partial coating only on theπ-phase-shifted grating region,the relative shift between the notch and flank wavelengths is employed to characterize the hydrogen concentration in this paper.The hydrogen calibration results show that the sensor shows the good response and repeatability.At the temperature of 20 and℃the hydrogen concentration of 2%,the wavelength distance shifts of 200 nm and 500 nm Pd/Hf coatings are 12.6 pm and 33.5 pm,respectively.展开更多
Introduction Pd/Ti double-layer thin film as non-evaporable getter(NEG)was deposited by sublimation,and its activation temperature was as low as 100℃.The Pd film was deposited in situ after Ti deposition to ensure no...Introduction Pd/Ti double-layer thin film as non-evaporable getter(NEG)was deposited by sublimation,and its activation temperature was as low as 100℃.The Pd film was deposited in situ after Ti deposition to ensure no oxidization on Ti film.Pumping speed test and characterization method The pumping speed of the coated pipe was measured by a pumping speed test system.The sticking factor was calculated by Molflow.The surface morphology was observed by a scanning electron microscope(SEM).The chemical composition of the film was measured by an energy-dispersive spectrum inbuilt with the SEM.The crystalline structure of the film was measured using grazing incidence X-ray diffraction.Conclusion It was found that the pumping performance of the Pd/Ti film still remained high after 15 times of activation.The maximum pumping speed after heating at 100℃for 24 h was 1.1 L/s cm^(2)and 0.49 L/s cm^(2)for H_(2)and CO,respectively.It can be concluded that the key to reducing the activation temperature of NEG materials is to enhance the oxidation resistance of the surface of NEG.展开更多
文摘The data of deformation strength and microstructure of thin films of nanocrystalline Pd recently provided by Colla et al. have been analysed. It is shown that the properties of the films with cylindrical grains of30 nm diameter extending over a significant portion of the film thickness（≈90 nm） are quantitatively comparable to what is known from nanocrystalline bulk material. This is explained in terms of boundarymediated processes governing emission, storage, and recovery of dislocations.
文摘The non-uniform argon dc glow discharge plasma system has been constructed in a very special design to investigate the effects of variable tube radius on plasma parameters. By using isolated computer controlled three couples of a double probe （TCDP） system, the electron temperature, electron density, the reduced electric field, and electron drift velocity are measured at low and intermediate pressures. It is shown that the electron temperature and reduced electric field （density） decreases （increases） as the radius decreases, at low discharge current and pressures. For large radius regions, at high discharge currents and pressures, the behaviour of the plasma parameters of specially reduced electric field change similarly to those in a uniform discharge system.
基金supported in part by the National Natural Science Foundation of China(Grant No.62025505)in part by the National Science Fund for Distinguished Young Scholars of China(Grant No.62061136002)in part by Deutsche Forschungsgemeinschaft(DFG),Germany(Grant No.448330062).
文摘A novel optical fiber hydrogen sensor based on theπ-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper.The hydrogen sensitive Pd/Hf film with the length of 4 mm is successfully deposited in theπ-phase-shifted grating region by the magnetron sputtering process and rotating fixture technology.Since the hydrogen sensitivity between the notch and flank wavelengths of theπ-phase-shifted grating is different due to the partial coating only on theπ-phase-shifted grating region,the relative shift between the notch and flank wavelengths is employed to characterize the hydrogen concentration in this paper.The hydrogen calibration results show that the sensor shows the good response and repeatability.At the temperature of 20 and℃the hydrogen concentration of 2%,the wavelength distance shifts of 200 nm and 500 nm Pd/Hf coatings are 12.6 pm and 33.5 pm,respectively.
基金provided by National Development and Reform Commission(Grand No.发改高技(2017)2173号)
文摘Introduction Pd/Ti double-layer thin film as non-evaporable getter(NEG)was deposited by sublimation,and its activation temperature was as low as 100℃.The Pd film was deposited in situ after Ti deposition to ensure no oxidization on Ti film.Pumping speed test and characterization method The pumping speed of the coated pipe was measured by a pumping speed test system.The sticking factor was calculated by Molflow.The surface morphology was observed by a scanning electron microscope(SEM).The chemical composition of the film was measured by an energy-dispersive spectrum inbuilt with the SEM.The crystalline structure of the film was measured using grazing incidence X-ray diffraction.Conclusion It was found that the pumping performance of the Pd/Ti film still remained high after 15 times of activation.The maximum pumping speed after heating at 100℃for 24 h was 1.1 L/s cm^(2)and 0.49 L/s cm^(2)for H_(2)and CO,respectively.It can be concluded that the key to reducing the activation temperature of NEG materials is to enhance the oxidation resistance of the surface of NEG.
