Al and Mn co-doped-ZnO films have been prepared at room temperature by DC reacti ve magnetron sputtering technique. The optical absorption coefficient, apparent and fundamental band gap, and work function of the films...Al and Mn co-doped-ZnO films have been prepared at room temperature by DC reacti ve magnetron sputtering technique. The optical absorption coefficient, apparent and fundamental band gap, and work function of the films have been investigated using optical spectroscopy, band structure analyses and ultraviolet photoelectro n spectroscopy (UPS). ZnO films have direct allowed transition band structure, w hich has been confirmed by the character of the optical absorption coefficient. The apparent band gap has been found directly proportional to N2/3, showing that the effect of Burstein-Moss shift on the band gap variations dominates over the many-body effect. With only standard cleaning protocols, the work function of ZnO: (Al, Mn) and ZnO: Al films have been measured to be 4.26 and 4.21eV, respec tively. The incorporation of Mn element into the matrix of ZnO, as a relatively deep donor, can remove some electrons from the conduction band and deplete the d ensity of occupied states at the Fermi energy, which causes a loss in measured p hotoemission intensity and an increase in the surface work function. Based on th e band gap and work function results, the energy band diagram of the ZnO: (Al, M n) film near its surface is also given.展开更多
A new hot-work die steel for hot stamping was developed, and used the die for mass production. The produced die showed good performance owing to its high heat conductivity and wear-resistant characteristics. Two diffe...A new hot-work die steel for hot stamping was developed, and used the die for mass production. The produced die showed good performance owing to its high heat conductivity and wear-resistant characteristics. Two different benchmarking hot-work die steels were investigated, and then compared in terms of their impact ductility, temper characteristics ,heat conductivity, and thermal stability. The result of the high-temperature friction wear test indicated that oxidative wear was the main mode in high temperature. On the basis of the comparison and test results, the alloying composition of the new hot-work die steel was especially designed. The new die steel showed good performance with good wear-resistant quality, as well as temper hardness and heat conductivity of HRC 50 and 34.3 W/（ m ~ K）, respectively. Furthermore, without surface plasma nitriding, the die made of the new steel had no obvious galling with 6 142 strokes. After surface plasma nitriding, the die completed 40 000 strokes with good surface. The die life is expected to exceed 200 000 strokes.展开更多
The main objective of this research work is to decrease work function of any given element or compound or material. To decrease the work function of the given material we have to decrease the bandwidth between conduct...The main objective of this research work is to decrease work function of any given element or compound or material. To decrease the work function of the given material we have to decrease the bandwidth between conduct band and valance band. Because according to definition of work function, the amount of energy that required the remove the electron from valance band of an atom and it is also called ionization energy. These all energies depend upon the band width that is greater than the band width greater energy required to remove the electron from the surface, and less than the band width and lesser amount of energy required to remove the electron from of materials. In this work we are trying to give an theoretical model or relation, how to decrease the work function of a material by applying external pressure on atoms and doping of the material that has screening or shielding effects. With the help of this model we can increase the efficiency of material used in solar cell that is cell work for all range of frequencies and by construction material bases on this we can increase the efficiency of solar cell or any type of material working solar cell principle.展开更多
为了保护带电作业人员的安全,计算分析了≥750 k V交流电压等级线路和±660 k V、±800 k V直流线路电位转移过程中的暂态能量,并开展了导电手套放电试验研究。理论和试验研究结果表明,当放电系统能量为1.37 J时,放电电弧的根...为了保护带电作业人员的安全,计算分析了≥750 k V交流电压等级线路和±660 k V、±800 k V直流线路电位转移过程中的暂态能量,并开展了导电手套放电试验研究。理论和试验研究结果表明,当放电系统能量为1.37 J时,放电电弧的根部直接作用在导电手套上,将导电手套烧蚀,对作业人员产生伤害。考虑实际作业安全裕度,在规定的电位转移距离下,≥750 k V交流线路和±660 k V、±800 k V直流线路电位转移的暂态能量>1.0 J时,需使用电位转移棒进行电位转移,确保电位转移人员的安全。展开更多
基金This work was supported by the National Nalural Science Foundation of China(No.50172051).
文摘Al and Mn co-doped-ZnO films have been prepared at room temperature by DC reacti ve magnetron sputtering technique. The optical absorption coefficient, apparent and fundamental band gap, and work function of the films have been investigated using optical spectroscopy, band structure analyses and ultraviolet photoelectro n spectroscopy (UPS). ZnO films have direct allowed transition band structure, w hich has been confirmed by the character of the optical absorption coefficient. The apparent band gap has been found directly proportional to N2/3, showing that the effect of Burstein-Moss shift on the band gap variations dominates over the many-body effect. With only standard cleaning protocols, the work function of ZnO: (Al, Mn) and ZnO: Al films have been measured to be 4.26 and 4.21eV, respec tively. The incorporation of Mn element into the matrix of ZnO, as a relatively deep donor, can remove some electrons from the conduction band and deplete the d ensity of occupied states at the Fermi energy, which causes a loss in measured p hotoemission intensity and an increase in the surface work function. Based on th e band gap and work function results, the energy band diagram of the ZnO: (Al, M n) film near its surface is also given.
文摘A new hot-work die steel for hot stamping was developed, and used the die for mass production. The produced die showed good performance owing to its high heat conductivity and wear-resistant characteristics. Two different benchmarking hot-work die steels were investigated, and then compared in terms of their impact ductility, temper characteristics ,heat conductivity, and thermal stability. The result of the high-temperature friction wear test indicated that oxidative wear was the main mode in high temperature. On the basis of the comparison and test results, the alloying composition of the new hot-work die steel was especially designed. The new die steel showed good performance with good wear-resistant quality, as well as temper hardness and heat conductivity of HRC 50 and 34.3 W/（ m ~ K）, respectively. Furthermore, without surface plasma nitriding, the die made of the new steel had no obvious galling with 6 142 strokes. After surface plasma nitriding, the die completed 40 000 strokes with good surface. The die life is expected to exceed 200 000 strokes.
文摘The main objective of this research work is to decrease work function of any given element or compound or material. To decrease the work function of the given material we have to decrease the bandwidth between conduct band and valance band. Because according to definition of work function, the amount of energy that required the remove the electron from valance band of an atom and it is also called ionization energy. These all energies depend upon the band width that is greater than the band width greater energy required to remove the electron from the surface, and less than the band width and lesser amount of energy required to remove the electron from of materials. In this work we are trying to give an theoretical model or relation, how to decrease the work function of a material by applying external pressure on atoms and doping of the material that has screening or shielding effects. With the help of this model we can increase the efficiency of material used in solar cell that is cell work for all range of frequencies and by construction material bases on this we can increase the efficiency of solar cell or any type of material working solar cell principle.
文摘为了保护带电作业人员的安全,计算分析了≥750 k V交流电压等级线路和±660 k V、±800 k V直流线路电位转移过程中的暂态能量,并开展了导电手套放电试验研究。理论和试验研究结果表明,当放电系统能量为1.37 J时,放电电弧的根部直接作用在导电手套上,将导电手套烧蚀,对作业人员产生伤害。考虑实际作业安全裕度,在规定的电位转移距离下,≥750 k V交流线路和±660 k V、±800 k V直流线路电位转移的暂态能量>1.0 J时,需使用电位转移棒进行电位转移,确保电位转移人员的安全。
