Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and or...Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.展开更多
The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and ...The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions展开更多
In this paper the dependence of flow stress in alloy GH169 on the deformation temperature, strain and strain rate based on the data of hot working simulation test is defined for the first time. Experimental results in...In this paper the dependence of flow stress in alloy GH169 on the deformation temperature, strain and strain rate based on the data of hot working simulation test is defined for the first time. Experimental results indicate that for the alloy GH169 the values of flow stress at high temperatures are much higher than those of alloy steel and the work hardening is remarkable. The deformation conditions have significant influence on the flow stress and microstructure of alloy GH169. It is found that under certain conditions fine grain structure can be obtained even though the deformation processes are carried out at high temperatures. This finding is beneficial to the raise of productivity of forming processes. Increasing the cooling rate after deformation is also favourable to the development of fine grain structure. To sum up, the microstructure of alloy GH169 can be controlled effectively through thermomechanical treatment.展开更多
The key to improve the naturalness of the synthetic speech is to build a perfect prosodic model. Thus the preliminary study of the influence of sentence stress on prosodic features in Standard Chinese is presented, in...The key to improve the naturalness of the synthetic speech is to build a perfect prosodic model. Thus the preliminary study of the influence of sentence stress on prosodic features in Standard Chinese is presented, in which the relationship between duration and pitch under different sentence stress levels is revealed. The results show that: (a) The pitch is the most important factor which carries the sentence stress, with the increase of the sentence stress level, the distribution of pitch moves towards high frequency area. (b) In the case of 'Stress' and 'Light', two peaks are found in the distribution of duration, which means that the duration of some words are affected by sentence stress, but of others are not. (c) The relationship between pitch and duration in 'Normal', 'Stress' and 'Light' are un-correlated, positive correlation and negative correlation respectively. The research lays a foundation for building a perfect prosodic model for standard Chinese speech synthesis system. The results of research are also used to classify sentence stress using a neural network, and 63% identification ratio has been obtained in an open set test. An automatic method for the sentence stress labeling is also suggested.展开更多
基金Supported by the Youth Science Foundation of Shanxi Province under Grant No 2013021010-3the National Natural Science Foundation of China under Grant Nos 61434002 and 11404202
文摘Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.
文摘The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions
文摘In this paper the dependence of flow stress in alloy GH169 on the deformation temperature, strain and strain rate based on the data of hot working simulation test is defined for the first time. Experimental results indicate that for the alloy GH169 the values of flow stress at high temperatures are much higher than those of alloy steel and the work hardening is remarkable. The deformation conditions have significant influence on the flow stress and microstructure of alloy GH169. It is found that under certain conditions fine grain structure can be obtained even though the deformation processes are carried out at high temperatures. This finding is beneficial to the raise of productivity of forming processes. Increasing the cooling rate after deformation is also favourable to the development of fine grain structure. To sum up, the microstructure of alloy GH169 can be controlled effectively through thermomechanical treatment.
文摘The key to improve the naturalness of the synthetic speech is to build a perfect prosodic model. Thus the preliminary study of the influence of sentence stress on prosodic features in Standard Chinese is presented, in which the relationship between duration and pitch under different sentence stress levels is revealed. The results show that: (a) The pitch is the most important factor which carries the sentence stress, with the increase of the sentence stress level, the distribution of pitch moves towards high frequency area. (b) In the case of 'Stress' and 'Light', two peaks are found in the distribution of duration, which means that the duration of some words are affected by sentence stress, but of others are not. (c) The relationship between pitch and duration in 'Normal', 'Stress' and 'Light' are un-correlated, positive correlation and negative correlation respectively. The research lays a foundation for building a perfect prosodic model for standard Chinese speech synthesis system. The results of research are also used to classify sentence stress using a neural network, and 63% identification ratio has been obtained in an open set test. An automatic method for the sentence stress labeling is also suggested.
