A new type of lead-based porous anode in zinc electrowinning was prepared by negative pressure infiltration. The anodic polarization potential and corrosion rate were studied and compared with those of traditional fia...A new type of lead-based porous anode in zinc electrowinning was prepared by negative pressure infiltration. The anodic polarization potential and corrosion rate were studied and compared with those of traditional fiat anodes （Pb-0.8%Ag） used in industry. The anode corrosion rate was determined by anode actual current density and microstructure. The results show that the anodic oxygen evolution potential decreases first and then increases with the decrease of pore diameter. The anodic potential decreases to the lowest value of 1.729 V at the pore diameter of 1.25-1.60 mm. The porous anode can decrease its actual current density and thus decrease the anodic corrosion rate. When the pore diameter is 1.60-2.00 mm, the anodic relative corrosion rate reaches the lowest value of 52.1%.展开更多
Based on planar Si dual-base transistor conception, a novel mesa dual-base heterojunc- tion bipolar transistor ( HBT) is designed and fabricated. Molecule beam extension. selective wet chemical etching, common contact...Based on planar Si dual-base transistor conception, a novel mesa dual-base heterojunc- tion bipolar transistor ( HBT) is designed and fabricated. Molecule beam extension. selective wet chemical etching, common contact photolithography and metal lift-off technique are adopted in the process. The device has particular and distinct voltage-controlled negative differential resistance (NDR) and photo-controlled NDR. The highest peak-to-vally current rate of the voltage-controlled NDR is larger than 148 and the peak current varies with the increase of collector voltage. The device features high speed and high frequency characteristics derived from HBT and intrinsic bistability and self-latching characteristics due to NDR. A single dual-base HBT can be seen as an integration of NDR device, HBT and photoconductive device. Compared with common HBT.the groove is the key factor producing NDR.展开更多
基金Project(2007SK2009) supported by the Science and Technology Research Project of Hunan Province, China
文摘A new type of lead-based porous anode in zinc electrowinning was prepared by negative pressure infiltration. The anodic polarization potential and corrosion rate were studied and compared with those of traditional fiat anodes （Pb-0.8%Ag） used in industry. The anode corrosion rate was determined by anode actual current density and microstructure. The results show that the anodic oxygen evolution potential decreases first and then increases with the decrease of pore diameter. The anodic potential decreases to the lowest value of 1.729 V at the pore diameter of 1.25-1.60 mm. The porous anode can decrease its actual current density and thus decrease the anodic corrosion rate. When the pore diameter is 1.60-2.00 mm, the anodic relative corrosion rate reaches the lowest value of 52.1%.
基金Supported by "973" National Key Basic Research Program ( No. 2002CB311905) andYoung Teacher Foundation of Tianjin University.
文摘Based on planar Si dual-base transistor conception, a novel mesa dual-base heterojunc- tion bipolar transistor ( HBT) is designed and fabricated. Molecule beam extension. selective wet chemical etching, common contact photolithography and metal lift-off technique are adopted in the process. The device has particular and distinct voltage-controlled negative differential resistance (NDR) and photo-controlled NDR. The highest peak-to-vally current rate of the voltage-controlled NDR is larger than 148 and the peak current varies with the increase of collector voltage. The device features high speed and high frequency characteristics derived from HBT and intrinsic bistability and self-latching characteristics due to NDR. A single dual-base HBT can be seen as an integration of NDR device, HBT and photoconductive device. Compared with common HBT.the groove is the key factor producing NDR.
