A method of data processing to determine the coefficients of linearization equations for 1050 anemometer (produced by Thermo-Systems Inc. -TSI, USA) with the sensors made of domestic hot wire using the program preferr...A method of data processing to determine the coefficients of linearization equations for 1050 anemometer (produced by Thermo-Systems Inc. -TSI, USA) with the sensors made of domestic hot wire using the program preferred in this Paper is described. By calculation and test, it is indicated that the error resulting from this method is about 0. 5% of the full scale and less than TSl's. By using this method we can set up the calibration curve according to the measurement range and the diameter of the hot wire at a certain accuracy.展开更多
An adaptive response compensation technique has been proposed to compensate for the response lag of the constant-current hot-wire anemometer (CCA) by taking advantage of digital signal processing technology. First, we...An adaptive response compensation technique has been proposed to compensate for the response lag of the constant-current hot-wire anemometer (CCA) by taking advantage of digital signal processing technology. First, we have developed a simple response compensation scheme based on a precise theoretical expression for the frequency response of the CCA (Kaifuku et al. 2010, 2011), and verified its effectiveness experimentally for hot-wires of 5 μm, 10 μm and 20 μm in diameter. Then, another novel technique based on a two-sensor probe technique—originally developed for the response compensation of fine-wire thermocouples (Tagawa and Ohta 1997;Tagawa et al. 1998)—has been proposed for estimating thermal time-constants of hot-wires to realize the in-situ response compensation of the CCA. To demonstrate the usefulness of the CCA, we have applied the response compensation schemes to multipoint velocity measure- ment of a turbulent wake flow formed behind a circular cylinder by using a CCA probe consisting of 16 hot-wires, which were driven simultaneously by a very simple constant-current circuit. As a result, the proposed response compensation techniques for the CCA work quite successfully and are capable of improving the response speed of the CCA to obtain reliable measurements comparable to those by the commercially-available constant-temperature hot-wire anemometer (CTA).展开更多
Hot wire measurements and flow visualization are presented for studying the turbulent flow field over a flat gas turbine film cooling blade with lateral expanded holes. Three mass flux ratios of jet to free stream, M ...Hot wire measurements and flow visualization are presented for studying the turbulent flow field over a flat gas turbine film cooling blade with lateral expanded holes. Three mass flux ratios of jet to free stream, M = 0.5, 0.89, 1.5, are tested. The streamwise velocity, the turbulent intensities and the Reynolds shear stress are measured. The effect of the lateral expanded holes on the improvement of the turbulent flow field for film cooling of gas turbines can be analyzed from the measured spatial di...展开更多
A novel type of n/i/i/p heterojunction solar cell with a-Si：H（15 nm）/a-Si：H（10 nm）/epitaxial c-Si（47 p.m）/epitaxial c-Si（3 um） structure is fabricated by using the layer transfer technique, and the emitter l...A novel type of n/i/i/p heterojunction solar cell with a-Si：H（15 nm）/a-Si：H（10 nm）/epitaxial c-Si（47 p.m）/epitaxial c-Si（3 um） structure is fabricated by using the layer transfer technique, and the emitter layer is deposited by hot wire chemical vapour deposition. The effect of the doping concentration of the emitter layer Sd （Sd=PH3/（PH3 ＋SiH4＋H2）） on the performance of the solar cell is studied by means of current density-voltage and external quantum efficiency. The results show that the conversion efficiency of the solar cell first increases to a maximum value and then decreases with Sd increasing from 0.1% to 0.4%. The best performance of the solar cell is obtained at Sd = 0.2% with an open circuit voltage of 534 mV, a short circuit current density of 23.35 mA/cm2, a fill factor of 63.3%, and a conversion efficiency of 7.9%.展开更多
GeSi:H films are prepared by hot-wire chemical vapor deposition(CVD) with high hydrogen dilution, DH=98%. Effects of hot wire temperature(Tw) on deposition rate, structural properties and bandgap of GeSi:H films are s...GeSi:H films are prepared by hot-wire chemical vapor deposition(CVD) with high hydrogen dilution, DH=98%. Effects of hot wire temperature(Tw) on deposition rate, structural properties and bandgap of GeSi:H films are studied with surface profilemeter, Raman spectroscopy, Fourier transformed infrared spectroscopy, and UV-VIS-NIR spectrophotometer. It is found that the deposition rate(Rd) goes up with increasing of Tw, but increasing rate of Rd declines when Tw≥1 550 ℃. High Tw is beneficial to the formation of Ge-Si, but it has little effect on relative contents of the hydrogen bonds(Ge-H, Si-H, etc.) in the films. In the Tw range of 1 400-1 850 ℃, the maximum bandgap of the GeSi:H films is 1.39 eV at Tw =1 450 ℃ and the band gap decreases with Tw increasing when Tw≥1 450 ℃.展开更多
文摘A method of data processing to determine the coefficients of linearization equations for 1050 anemometer (produced by Thermo-Systems Inc. -TSI, USA) with the sensors made of domestic hot wire using the program preferred in this Paper is described. By calculation and test, it is indicated that the error resulting from this method is about 0. 5% of the full scale and less than TSl's. By using this method we can set up the calibration curve according to the measurement range and the diameter of the hot wire at a certain accuracy.
文摘An adaptive response compensation technique has been proposed to compensate for the response lag of the constant-current hot-wire anemometer (CCA) by taking advantage of digital signal processing technology. First, we have developed a simple response compensation scheme based on a precise theoretical expression for the frequency response of the CCA (Kaifuku et al. 2010, 2011), and verified its effectiveness experimentally for hot-wires of 5 μm, 10 μm and 20 μm in diameter. Then, another novel technique based on a two-sensor probe technique—originally developed for the response compensation of fine-wire thermocouples (Tagawa and Ohta 1997;Tagawa et al. 1998)—has been proposed for estimating thermal time-constants of hot-wires to realize the in-situ response compensation of the CCA. To demonstrate the usefulness of the CCA, we have applied the response compensation schemes to multipoint velocity measure- ment of a turbulent wake flow formed behind a circular cylinder by using a CCA probe consisting of 16 hot-wires, which were driven simultaneously by a very simple constant-current circuit. As a result, the proposed response compensation techniques for the CCA work quite successfully and are capable of improving the response speed of the CCA to obtain reliable measurements comparable to those by the commercially-available constant-temperature hot-wire anemometer (CTA).
文摘Hot wire measurements and flow visualization are presented for studying the turbulent flow field over a flat gas turbine film cooling blade with lateral expanded holes. Three mass flux ratios of jet to free stream, M = 0.5, 0.89, 1.5, are tested. The streamwise velocity, the turbulent intensities and the Reynolds shear stress are measured. The effect of the lateral expanded holes on the improvement of the turbulent flow field for film cooling of gas turbines can be analyzed from the measured spatial di...
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2006AA03Z219)the Jiangsu Innovation Program for Graduate Education, China (Grant No. CXZZ11 0206)the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘A novel type of n/i/i/p heterojunction solar cell with a-Si：H（15 nm）/a-Si：H（10 nm）/epitaxial c-Si（47 p.m）/epitaxial c-Si（3 um） structure is fabricated by using the layer transfer technique, and the emitter layer is deposited by hot wire chemical vapour deposition. The effect of the doping concentration of the emitter layer Sd （Sd=PH3/（PH3 ＋SiH4＋H2）） on the performance of the solar cell is studied by means of current density-voltage and external quantum efficiency. The results show that the conversion efficiency of the solar cell first increases to a maximum value and then decreases with Sd increasing from 0.1% to 0.4%. The best performance of the solar cell is obtained at Sd = 0.2% with an open circuit voltage of 534 mV, a short circuit current density of 23.35 mA/cm2, a fill factor of 63.3%, and a conversion efficiency of 7.9%.
基金Supported by the National Key Research and Development Program of China(2018YFB1500400-2018YFB1500403)the National Natural Science Foundation of China(61741404,61464007)the Jiangxi Provincial Key Research and Development Foundation(2016BBH80043)
文摘GeSi:H films are prepared by hot-wire chemical vapor deposition(CVD) with high hydrogen dilution, DH=98%. Effects of hot wire temperature(Tw) on deposition rate, structural properties and bandgap of GeSi:H films are studied with surface profilemeter, Raman spectroscopy, Fourier transformed infrared spectroscopy, and UV-VIS-NIR spectrophotometer. It is found that the deposition rate(Rd) goes up with increasing of Tw, but increasing rate of Rd declines when Tw≥1 550 ℃. High Tw is beneficial to the formation of Ge-Si, but it has little effect on relative contents of the hydrogen bonds(Ge-H, Si-H, etc.) in the films. In the Tw range of 1 400-1 850 ℃, the maximum bandgap of the GeSi:H films is 1.39 eV at Tw =1 450 ℃ and the band gap decreases with Tw increasing when Tw≥1 450 ℃.
