The Mechanical properties of the hexagonal tungsten nanowhiskers, which were synthesized by chemical vapor deposition, were characterized by instrumented nanoindentation and atomic force microscope （AFM）. The nanoin...The Mechanical properties of the hexagonal tungsten nanowhiskers, which were synthesized by chemical vapor deposition, were characterized by instrumented nanoindentation and atomic force microscope （AFM）. The nanoindentation results show that tungsten nanowhiskers exhibit a hardness of （6.2±1.7） GPa and an elastic modulus of （225±20） GPa. According to the comparative test results, the tungsten nanowhiskers possess a comparable hardness to tungsten microwhiskers, and an hardness increase of 35% to the bulk single-crystal tungsten. The increase in the hardness of whiskers is attributed to the lacking of dislocation avalanche observed in the bulk single-crystal tungsten. The measured modulus is about 80% that of the tungsten microwhiskers, which can be contributed to the size effects of the nanowhiskers and the substrate effects in the nanoindentation test.展开更多
提出了用信号流图法设计n阶基于多端输出的电流控制第二代电流传输器(current controlled sec-ond generation current conveyor with multiple outputs,简记为MOCCCII)和第二代电流传输器(the second genera-tion current conveyor,简...提出了用信号流图法设计n阶基于多端输出的电流控制第二代电流传输器(current controlled sec-ond generation current conveyor with multiple outputs,简记为MOCCCII)和第二代电流传输器(the second genera-tion current conveyor,简称CCII)电流模式低通滤波器的方法.由该方法导出的滤波器所需元件较少,n阶滤波器仅需1个CCII-、n个MOCCCII和n个电容,所有电容均接地,便于集成且与VLSI工艺兼容.该滤波器可用于通信、电子测量与仪器仪表的信号处理.该文给出了2、3和4阶滤波器的设计实例,PSPISE仿真结果与理论分析相吻合,验证了该方法的可行性.展开更多
基金Projects(50804057,51074188) supported by the National Natural Science Foundation of ChinaProject(08C580) supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProjects(2012T50703,2011M500128) supported by China Postdoctoral Science Foundation Funded Project and Postdoctoral Science Foundation of Central South University,China
文摘The Mechanical properties of the hexagonal tungsten nanowhiskers, which were synthesized by chemical vapor deposition, were characterized by instrumented nanoindentation and atomic force microscope （AFM）. The nanoindentation results show that tungsten nanowhiskers exhibit a hardness of （6.2±1.7） GPa and an elastic modulus of （225±20） GPa. According to the comparative test results, the tungsten nanowhiskers possess a comparable hardness to tungsten microwhiskers, and an hardness increase of 35% to the bulk single-crystal tungsten. The increase in the hardness of whiskers is attributed to the lacking of dislocation avalanche observed in the bulk single-crystal tungsten. The measured modulus is about 80% that of the tungsten microwhiskers, which can be contributed to the size effects of the nanowhiskers and the substrate effects in the nanoindentation test.
文摘提出了用信号流图法设计n阶基于多端输出的电流控制第二代电流传输器(current controlled sec-ond generation current conveyor with multiple outputs,简记为MOCCCII)和第二代电流传输器(the second genera-tion current conveyor,简称CCII)电流模式低通滤波器的方法.由该方法导出的滤波器所需元件较少,n阶滤波器仅需1个CCII-、n个MOCCCII和n个电容,所有电容均接地,便于集成且与VLSI工艺兼容.该滤波器可用于通信、电子测量与仪器仪表的信号处理.该文给出了2、3和4阶滤波器的设计实例,PSPISE仿真结果与理论分析相吻合,验证了该方法的可行性.
