为提高电动汽车再生制动能量,分析制动力及制动力分配方式,选取理想制动力分配曲线I曲线、固定分配线β线进行制动效果仿真对比;根据汽车制动要求制定模糊规则,结合制动强度、车速和电池荷电状态确定电机制动力分配因数;采用MATLAB-Simu...为提高电动汽车再生制动能量,分析制动力及制动力分配方式,选取理想制动力分配曲线I曲线、固定分配线β线进行制动效果仿真对比;根据汽车制动要求制定模糊规则,结合制动强度、车速和电池荷电状态确定电机制动力分配因数;采用MATLAB-Simulink建立制动模型,对比I曲线、β线的再生制动效果,并以新欧洲行驶循环(new European driving cycle,NEDC)工况的制动部分进行验证。仿真结果表明:在制动强度为0.5时,I曲线与β线制动效果差距较小;在制动强度为0.8时,I曲线与β线制动效果相同;车速为50 km/h,制动强度为0.5时,采用模糊规则控制分配制动力,β线比I曲线电机制动能量高8.78%;NEDC工况下I曲线与β线的制动总能量变化一致,β线电机制动能量比I曲线高13.58%。采用β线制动力分配方式可以提高电机再生制动能量,有效实现能量回收。展开更多
Generally, the walls of ceramic ware are thin and the sample to be used for TL dating has to be collected from 1￣2mm under the surface.This call introduce significant error into the dating method.Therefore,the result...Generally, the walls of ceramic ware are thin and the sample to be used for TL dating has to be collected from 1￣2mm under the surface.This call introduce significant error into the dating method.Therefore,the results of a series of simulated experiments are reported on the build-up effect of the internal β dose response in different thicknesses of pottery fragments (involving tile and brick).Correction factors,corresponding to different thicknesses,and correction 'depths' are proposed in terms of the experimental findings which may be incorporatd into the dating methods.展开更多
The effects of on-line solution, off-line solution and aging heat treatment on the microstructure and hardness of the die-cast AZ91D alloys were investigated. Brinell hardness of die-cast AZ91D alloy increases through...The effects of on-line solution, off-line solution and aging heat treatment on the microstructure and hardness of the die-cast AZ91D alloys were investigated. Brinell hardness of die-cast AZ91D alloy increases through on-line solution and off-line aging treatment but decreases after off-line solution treatment. By X-ray diffractometry, optical microscopy, differential thermal analysis, scanning electron microscopy and X-ray energy dispersive spectroscopy, it is found that the microstructures of the die-cast AZ91D magnesium alloy before and after on-line solution and off-line aging are similar, consisting of α-Mg and β-Al12Mg17. The precipitation of Al element is prevented by on-line solution so that the effect of solid solution strengthening is enhanced. The β-Al12Mg17 phases precipitate from supersaturated Mg solid solution after off-line aging treatment, and lead to microstructure refinement of AZ91D alloy, so the effect of precipitation hardening is enhanced. The β-Al12Mg17 phases dissolve in the substructure after off-line solution treatment, which leads to that the grain boundary strengthening phase is reduced significantly and the hardness of die cast AZ91D is reduced.展开更多
Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre-coated(111) silicon substrates with chemical vapor deposition(CVD) technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pr...Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre-coated(111) silicon substrates with chemical vapor deposition(CVD) technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pressure the large-scale preparation of β-Ga2O3 with monoclinic crystalline structure is achieved. The crystalline structures and morphologies of produced Ga2O3 nano-structures are characterized by means of scanning electron microscope(SEM), X-ray diffraction(XRD), selected area electron diffraction(SAED) and transmission electron microscope(TEM). Raman spectrum reveals the typical vibration modes of Ga2O3. The vibration mode shifts corresponding to Ga2O3 nano-structures are not found. Two distinguish photoluminescence(PL) emissions are found at about 399 nm and 469 nm owing to the VO-VGa excitation and VO-VGa-O excitation, respectively. The growth mechanisms of Ga2O3 nanowires and nanosheets are discussed with vapor-liquid-solid(VLS) and vapor-solid(VS) mechanisms.展开更多
The propagation of Rossby waves on the Earth’s δ-surface is discussed in a reference frame propagation with the zonal phase speed of the wave.In this reference frame,trajectories and streamlines coincide;the propaga...The propagation of Rossby waves on the Earth’s δ-surface is discussed in a reference frame propagation with the zonal phase speed of the wave.In this reference frame,trajectories and streamlines coincide;the propagation of Rossby waves has a different interpretation than in a reference frame fixed on the ground;and the mechanism for the propagation of Rossby waves depends not only on the different positions of the wave relative to the basic current,but also the variation ofβwith latitude(called theδ-effect).展开更多
A high order single step β algorithm, a new direct integration algorithm is proposed for solution of equations of motion. Whenβ=0.5, the accuracy of displacement, velocity and acceleration is of forth order (a trunc...A high order single step β algorithm, a new direct integration algorithm is proposed for solution of equations of motion. Whenβ=0.5, the accuracy of displacement, velocity and acceleration is of forth order (a truncation error of Δ t 5), and the algorithm is unconditionally stable and has no arithmetic damping and no overshooting. When >0.5, and an arithmetic damping is adopted, the algorithm is again unconditionally stable with a third order accuracy (a truncation error of Δ t 4). The analyses run with typical examples show that the algorithm proposed has higher speed, higher precision and better properties than other direct integration methods, such as Wilson θ method and Newmark β method in analysing linear elastic responses and nonlinear earthquake responses.展开更多
Cinnamon and its major active component, cinnamaldehyde, have been shown to be neuroprotective in models of Alzheimer＇s disease （AD）. To further investigate the mechanism of cinnamaldehyde, we investigated the effe...Cinnamon and its major active component, cinnamaldehyde, have been shown to be neuroprotective in models of Alzheimer＇s disease （AD）. To further investigate the mechanism of cinnamaldehyde, we investigated the effects of cinnamaldehyde focusing on mitochondrial function in SH-SYSY neural cells. The results demonstrated that cinnamaldehyde could enhance neural cell viability with or without increased Aβ levels. Cinnamaldehyde facilitated the maintenance of normal mitochondrial morphology, preserved the mitochondrial membrane potential （ATm）, and reduced production of reactive oxygen species （ROS）. Cinnamaldehyde also decreased the expression of dynamin-related protein 1 （Drpl）, a protein critically involved in mitochondrial dynamics. In addition, cinnamaldehyde inhibited Aβ oligomerization, but it had no effects on Tau phosphorylation. In overall, cinnamaldehyde promoted mitochondrial function and inhibited Aβ toxicity, and these two properties may both contribute to the neuroprotective effect. These results suggest that cinnamaldehyde could be a potential nutriceutical in the prevention and even therapeutic treatment of AD as well as other aging-related metabolic syndromes.展开更多
文摘为提高电动汽车再生制动能量,分析制动力及制动力分配方式,选取理想制动力分配曲线I曲线、固定分配线β线进行制动效果仿真对比;根据汽车制动要求制定模糊规则,结合制动强度、车速和电池荷电状态确定电机制动力分配因数;采用MATLAB-Simulink建立制动模型,对比I曲线、β线的再生制动效果,并以新欧洲行驶循环(new European driving cycle,NEDC)工况的制动部分进行验证。仿真结果表明:在制动强度为0.5时,I曲线与β线制动效果差距较小;在制动强度为0.8时,I曲线与β线制动效果相同;车速为50 km/h,制动强度为0.5时,采用模糊规则控制分配制动力,β线比I曲线电机制动能量高8.78%;NEDC工况下I曲线与β线的制动总能量变化一致,β线电机制动能量比I曲线高13.58%。采用β线制动力分配方式可以提高电机再生制动能量,有效实现能量回收。
文摘Generally, the walls of ceramic ware are thin and the sample to be used for TL dating has to be collected from 1￣2mm under the surface.This call introduce significant error into the dating method.Therefore,the results of a series of simulated experiments are reported on the build-up effect of the internal β dose response in different thicknesses of pottery fragments (involving tile and brick).Correction factors,corresponding to different thicknesses,and correction 'depths' are proposed in terms of the experimental findings which may be incorporatd into the dating methods.
基金Projects (2011BAE22B01, 2011BAE22B06) supported by the National Key Technologies R&D Program During the 12th Five-Year Plan Period of ChinaProject (2010NC018) supported by the Innovation Fund of Inner Mongolia University of Science and Technology, China
文摘The effects of on-line solution, off-line solution and aging heat treatment on the microstructure and hardness of the die-cast AZ91D alloys were investigated. Brinell hardness of die-cast AZ91D alloy increases through on-line solution and off-line aging treatment but decreases after off-line solution treatment. By X-ray diffractometry, optical microscopy, differential thermal analysis, scanning electron microscopy and X-ray energy dispersive spectroscopy, it is found that the microstructures of the die-cast AZ91D magnesium alloy before and after on-line solution and off-line aging are similar, consisting of α-Mg and β-Al12Mg17. The precipitation of Al element is prevented by on-line solution so that the effect of solid solution strengthening is enhanced. The β-Al12Mg17 phases precipitate from supersaturated Mg solid solution after off-line aging treatment, and lead to microstructure refinement of AZ91D alloy, so the effect of precipitation hardening is enhanced. The β-Al12Mg17 phases dissolve in the substructure after off-line solution treatment, which leads to that the grain boundary strengthening phase is reduced significantly and the hardness of die cast AZ91D is reduced.
文摘Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre-coated(111) silicon substrates with chemical vapor deposition(CVD) technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pressure the large-scale preparation of β-Ga2O3 with monoclinic crystalline structure is achieved. The crystalline structures and morphologies of produced Ga2O3 nano-structures are characterized by means of scanning electron microscope(SEM), X-ray diffraction(XRD), selected area electron diffraction(SAED) and transmission electron microscope(TEM). Raman spectrum reveals the typical vibration modes of Ga2O3. The vibration mode shifts corresponding to Ga2O3 nano-structures are not found. Two distinguish photoluminescence(PL) emissions are found at about 399 nm and 469 nm owing to the VO-VGa excitation and VO-VGa-O excitation, respectively. The growth mechanisms of Ga2O3 nanowires and nanosheets are discussed with vapor-liquid-solid(VLS) and vapor-solid(VS) mechanisms.
基金supported by the National Natural Science Foundation of China [grant numbers 11362012,11562014,41465002,and 41765004]the High School Science Research Project of the Inner Mongolia Autonomous Region[grant number NJZY16096]the Natural Science Foundation of Inner Mongolia[grant number 2018LH04005]
文摘The propagation of Rossby waves on the Earth’s δ-surface is discussed in a reference frame propagation with the zonal phase speed of the wave.In this reference frame,trajectories and streamlines coincide;the propagation of Rossby waves has a different interpretation than in a reference frame fixed on the ground;and the mechanism for the propagation of Rossby waves depends not only on the different positions of the wave relative to the basic current,but also the variation ofβwith latitude(called theδ-effect).
文摘A high order single step β algorithm, a new direct integration algorithm is proposed for solution of equations of motion. Whenβ=0.5, the accuracy of displacement, velocity and acceleration is of forth order (a truncation error of Δ t 5), and the algorithm is unconditionally stable and has no arithmetic damping and no overshooting. When >0.5, and an arithmetic damping is adopted, the algorithm is again unconditionally stable with a third order accuracy (a truncation error of Δ t 4). The analyses run with typical examples show that the algorithm proposed has higher speed, higher precision and better properties than other direct integration methods, such as Wilson θ method and Newmark β method in analysing linear elastic responses and nonlinear earthquake responses.
基金National Natural Science Foundation of China(Grant No.21571006 and 21271012)Beijing Natural Science Foundation(Grant No.7164308)
文摘Cinnamon and its major active component, cinnamaldehyde, have been shown to be neuroprotective in models of Alzheimer＇s disease （AD）. To further investigate the mechanism of cinnamaldehyde, we investigated the effects of cinnamaldehyde focusing on mitochondrial function in SH-SYSY neural cells. The results demonstrated that cinnamaldehyde could enhance neural cell viability with or without increased Aβ levels. Cinnamaldehyde facilitated the maintenance of normal mitochondrial morphology, preserved the mitochondrial membrane potential （ATm）, and reduced production of reactive oxygen species （ROS）. Cinnamaldehyde also decreased the expression of dynamin-related protein 1 （Drpl）, a protein critically involved in mitochondrial dynamics. In addition, cinnamaldehyde inhibited Aβ oligomerization, but it had no effects on Tau phosphorylation. In overall, cinnamaldehyde promoted mitochondrial function and inhibited Aβ toxicity, and these two properties may both contribute to the neuroprotective effect. These results suggest that cinnamaldehyde could be a potential nutriceutical in the prevention and even therapeutic treatment of AD as well as other aging-related metabolic syndromes.
