SEM microfractography of near-threshold fatigue crack propagation were carried out in the dual-phase steels of 3 martensite morphologies and 6 volume fractions of martensite (V_m). All of them are featured by cyclic c...SEM microfractography of near-threshold fatigue crack propagation were carried out in the dual-phase steels of 3 martensite morphologies and 6 volume fractions of martensite (V_m). All of them are featured by cyclic cleavage characteristics in near-threshold region,i.e.,main- ly controlled by mode Ⅱ stress.In the higher ΔK regions,the fracture surfaces are character- ized by mixed modes including cyclic cleavage facets,two types of secondary cracks and striations,etc..The roughness-induced crack closure of fracture surface is attributed primarily to extreme high fatigue crack growth threshold values.展开更多
The uniformity of threshold voltage and threshold current in the In2 Se3 nanowire-based phase change memory （PCM） devices is investigated. Based on the trap-limited transport model, amorphous layer thickness, trap d...The uniformity of threshold voltage and threshold current in the In2 Se3 nanowire-based phase change memory （PCM） devices is investigated. Based on the trap-limited transport model, amorphous layer thickness, trap density, and trap depth are considered to clarify their influences upon the threshold voltage and threshold current through simulations.展开更多
The envelope of a hypersonic vehicle is affected by severe fluctuating pressure, which causes the airborne antenna to vibrate slightly. This vibration mixes with the transmitted signals and thus introduces additional ...The envelope of a hypersonic vehicle is affected by severe fluctuating pressure, which causes the airborne antenna to vibrate slightly. This vibration mixes with the transmitted signals and thus introduces additional multiplicative phase noise. Antenna vibration and signal coupling effects as well as their influence on the lock threshold of the hypersonic vehicle carrier tracking system of the Ka band are investigated in this study. A vibration model is initially established to obtain phase noise in consideration of the inherent relationship between vibration displacement and electromagnetic wavelength. An analytical model of the Phase-Locked Loop（PLL）, which is widely used in carrier tracking systems, is established. The coupling effects on carrier tracking performance are investigated and quantitatively analyzed by imposing the multiplicative phase noise on the PLL model. Simulation results show that the phase noise presents a Gaussian distribution and is similar to vibration displacement variation. A large standard deviation in vibration displacement exerts a significant effect on the lock threshold. A critical standard deviation is observed in the PLL of Binary Phase Shift Keying（BPSK） and Quadrature Phase Shift Keying（QPSK） signals. The effect on QPSK signals is more severe than that on BPSK signals. The maximum tolerable standard deviations normalized by the wavelength of the carrier are 0.04 and 0.02 for BPSK and QPSK signals,respectively. With these critical standard deviations, lock thresholds are increased from à12 andà4 d B to 3 and à2 d B, respectively.展开更多
基于条件预充电技术,设计了一种高速低功耗真单相时钟触发器。在存在冗余开关活动的关键路径中,通过增加场效应管和控制条件,控制内部节点的冗余预充电活动;通过消除冗余结构,消除冗余的场效应管,从而改善电路结构,降低功耗和总功耗延...基于条件预充电技术,设计了一种高速低功耗真单相时钟触发器。在存在冗余开关活动的关键路径中,通过增加场效应管和控制条件,控制内部节点的冗余预充电活动;通过消除冗余结构,消除冗余的场效应管,从而改善电路结构,降低功耗和总功耗延时积。通用电路分析程序(simulation program with integrated circuit emphasis,HSPICE)仿真结果表明,在100 MHz的工作频率与低阈值电压下,触发器功耗低至158.6127 nW、总功耗延时积低至0.048735 fJ,电路具有正确的逻辑功能,且在功耗、延迟方面均优于近几年提出的电路。展开更多
文摘SEM microfractography of near-threshold fatigue crack propagation were carried out in the dual-phase steels of 3 martensite morphologies and 6 volume fractions of martensite (V_m). All of them are featured by cyclic cleavage characteristics in near-threshold region,i.e.,main- ly controlled by mode Ⅱ stress.In the higher ΔK regions,the fracture surfaces are character- ized by mixed modes including cyclic cleavage facets,two types of secondary cracks and striations,etc..The roughness-induced crack closure of fracture surface is attributed primarily to extreme high fatigue crack growth threshold values.
基金supported by the National Basic Research Program of China(Grant No.2011CBA00604)
文摘The uniformity of threshold voltage and threshold current in the In2 Se3 nanowire-based phase change memory （PCM） devices is investigated. Based on the trap-limited transport model, amorphous layer thickness, trap density, and trap depth are considered to clarify their influences upon the threshold voltage and threshold current through simulations.
基金co-supported by the National Basic Research Program of China (No. 2014CB340205)the Natural Science Foundation of Shaanxi Provincial Department of Education (No. 2016JM6016)the National Natural Science Foundation of China (No. 61473228)
文摘The envelope of a hypersonic vehicle is affected by severe fluctuating pressure, which causes the airborne antenna to vibrate slightly. This vibration mixes with the transmitted signals and thus introduces additional multiplicative phase noise. Antenna vibration and signal coupling effects as well as their influence on the lock threshold of the hypersonic vehicle carrier tracking system of the Ka band are investigated in this study. A vibration model is initially established to obtain phase noise in consideration of the inherent relationship between vibration displacement and electromagnetic wavelength. An analytical model of the Phase-Locked Loop（PLL）, which is widely used in carrier tracking systems, is established. The coupling effects on carrier tracking performance are investigated and quantitatively analyzed by imposing the multiplicative phase noise on the PLL model. Simulation results show that the phase noise presents a Gaussian distribution and is similar to vibration displacement variation. A large standard deviation in vibration displacement exerts a significant effect on the lock threshold. A critical standard deviation is observed in the PLL of Binary Phase Shift Keying（BPSK） and Quadrature Phase Shift Keying（QPSK） signals. The effect on QPSK signals is more severe than that on BPSK signals. The maximum tolerable standard deviations normalized by the wavelength of the carrier are 0.04 and 0.02 for BPSK and QPSK signals,respectively. With these critical standard deviations, lock thresholds are increased from à12 andà4 d B to 3 and à2 d B, respectively.
文摘基于条件预充电技术,设计了一种高速低功耗真单相时钟触发器。在存在冗余开关活动的关键路径中,通过增加场效应管和控制条件,控制内部节点的冗余预充电活动;通过消除冗余结构,消除冗余的场效应管,从而改善电路结构,降低功耗和总功耗延时积。通用电路分析程序(simulation program with integrated circuit emphasis,HSPICE)仿真结果表明,在100 MHz的工作频率与低阈值电压下,触发器功耗低至158.6127 nW、总功耗延时积低至0.048735 fJ,电路具有正确的逻辑功能,且在功耗、延迟方面均优于近几年提出的电路。
