The effect of short-range ordering (SRO) on the low-cycle fatigue (LCF) behavior of low solid-solution hardening Ni-Cr alloys with high stacking fault energies (SFEs) was systematically studied under cycling at consta...The effect of short-range ordering (SRO) on the low-cycle fatigue (LCF) behavior of low solid-solution hardening Ni-Cr alloys with high stacking fault energies (SFEs) was systematically studied under cycling at constant total strain amplitude (Δε t /2) in the range of 0.1%–0.7%. The results show that an inducement of SRO structures can notably improve the fatigue life of the alloy regardless of Δε t /2, and several unique fatigue characteristics have been detected, including the transition of fatigue cracking mode from intergranular cracking to slip band cracking, the non-negligible evolution from non-Masing behavior in pure Ni to Masing behavior in the Ni-40Cr alloy, and the secondary cyclic hardening behavior in the Ni-10Cr and Ni-20Cr alloys. All these experimental phenomena are tightly associated with the transformation in cyclic deformation mechanisms that is induced by SRO based on the “glide plane softening” effect. Furthermore, a comprehensive fatigue life prediction model based on total hysteresis energy has been reasonably proposed, focusing on the analyses of the macroscopic model parameters (namely the fatigue cracking resistance exponent β and the crack propagation resistance parameter W 0 ) and microscopic damage mechanisms. In brief, on the premise that the effects of SFE and friction stress can be nearly ignored, as in the case of the present low solid-solution hardening Ni-Cr alloys with high SFEs, an enhancement of SRO in face-centered cubic metals has been convincingly confirmed to be an effective strategy to improve their LCF performance.展开更多
Based on the technique of integral within a Weyl ordered product of operators, we present applications of the Weyl ordered two-mode Wigner operator for quantum mechanical entangled system, e.g., we derive the complex ...Based on the technique of integral within a Weyl ordered product of operators, we present applications of the Weyl ordered two-mode Wigner operator for quantum mechanical entangled system, e.g., we derive the complex Wigner transform and its relation to the complex fractional Fourier transform, as well as the entangled Radon transform.展开更多
Raman spectra of a complex perovskite system(Pb_(1-x)Ba_(x))(Yb_(0.5)Ta_(0.5))O_(3),x=0.0;0.1 and 0.2 have been studied at low temperature in the range of 10–250 K.The fascination of the system is that it undergoes a...Raman spectra of a complex perovskite system(Pb_(1-x)Ba_(x))(Yb_(0.5)Ta_(0.5))O_(3),x=0.0;0.1 and 0.2 have been studied at low temperature in the range of 10–250 K.The fascination of the system is that it undergoes a crossover from a highly ordered antiferroelectric(x=0.0)to ferroelectric(x=0.1)to disordered relaxor ferroelectric(x=0.2).The nature of splitting that prevails in F_(2g)(≈60 cm^(-1)),F_(1g)(≈538 cm^(-1))modes and their gradual merging and disappearance with x indicates an orthorhombic symmetry for x=0.0 and a pseudo-cubic structure for x=0.2.The mode at 420 cm^(-1) suggests the existence of rhombohedral distortion in all the compositions.The soft mode behavior of the F2g modes has been analyzed by fitting the data with the power law ω_(s)=A(T_(C)-T)^(β).展开更多
It has been common knowledge that the single-mode squeezing operator and the two-mode squeezing operator are independent of each other. However, in this work we find that after using the technique of integration with...It has been common knowledge that the single-mode squeezing operator and the two-mode squeezing operator are independent of each other. However, in this work we find that after using the technique of integration within Ω-ordering and β-ordering, we can detach two single-mode squeezing operators from the two-mode squeezing operator. In other words, we show that the two-mode squeezing operator can be split into a β-ordered two-mode squeezing operator （with a new squeezing parameter） and two single-mode squeezing operators （with another squeezing parameter）. This tells us that the two-mode squeezing mechanism also involves some single-mode squeezing.展开更多
基金financially supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.51571058 and 52171108。
文摘The effect of short-range ordering (SRO) on the low-cycle fatigue (LCF) behavior of low solid-solution hardening Ni-Cr alloys with high stacking fault energies (SFEs) was systematically studied under cycling at constant total strain amplitude (Δε t /2) in the range of 0.1%–0.7%. The results show that an inducement of SRO structures can notably improve the fatigue life of the alloy regardless of Δε t /2, and several unique fatigue characteristics have been detected, including the transition of fatigue cracking mode from intergranular cracking to slip band cracking, the non-negligible evolution from non-Masing behavior in pure Ni to Masing behavior in the Ni-40Cr alloy, and the secondary cyclic hardening behavior in the Ni-10Cr and Ni-20Cr alloys. All these experimental phenomena are tightly associated with the transformation in cyclic deformation mechanisms that is induced by SRO based on the “glide plane softening” effect. Furthermore, a comprehensive fatigue life prediction model based on total hysteresis energy has been reasonably proposed, focusing on the analyses of the macroscopic model parameters (namely the fatigue cracking resistance exponent β and the crack propagation resistance parameter W 0 ) and microscopic damage mechanisms. In brief, on the premise that the effects of SFE and friction stress can be nearly ignored, as in the case of the present low solid-solution hardening Ni-Cr alloys with high SFEs, an enhancement of SRO in face-centered cubic metals has been convincingly confirmed to be an effective strategy to improve their LCF performance.
基金The project supported by National Natural Science Foundation of China under Grant No.10175057
文摘Based on the technique of integral within a Weyl ordered product of operators, we present applications of the Weyl ordered two-mode Wigner operator for quantum mechanical entangled system, e.g., we derive the complex Wigner transform and its relation to the complex fractional Fourier transform, as well as the entangled Radon transform.
文摘Raman spectra of a complex perovskite system(Pb_(1-x)Ba_(x))(Yb_(0.5)Ta_(0.5))O_(3),x=0.0;0.1 and 0.2 have been studied at low temperature in the range of 10–250 K.The fascination of the system is that it undergoes a crossover from a highly ordered antiferroelectric(x=0.0)to ferroelectric(x=0.1)to disordered relaxor ferroelectric(x=0.2).The nature of splitting that prevails in F_(2g)(≈60 cm^(-1)),F_(1g)(≈538 cm^(-1))modes and their gradual merging and disappearance with x indicates an orthorhombic symmetry for x=0.0 and a pseudo-cubic structure for x=0.2.The mode at 420 cm^(-1) suggests the existence of rhombohedral distortion in all the compositions.The soft mode behavior of the F2g modes has been analyzed by fitting the data with the power law ω_(s)=A(T_(C)-T)^(β).
基金supported by the Fundamental Research Funds for the Central Universities of China (Grant No. WK2060140013)
文摘It has been common knowledge that the single-mode squeezing operator and the two-mode squeezing operator are independent of each other. However, in this work we find that after using the technique of integration within Ω-ordering and β-ordering, we can detach two single-mode squeezing operators from the two-mode squeezing operator. In other words, we show that the two-mode squeezing operator can be split into a β-ordered two-mode squeezing operator （with a new squeezing parameter） and two single-mode squeezing operators （with another squeezing parameter）. This tells us that the two-mode squeezing mechanism also involves some single-mode squeezing.
