A reaction-diffusion model for a single species with age structure and nonlocal reaction for periodic time t is derived. Some results about the model with monotone birth function are firstly introduced, and then by co...A reaction-diffusion model for a single species with age structure and nonlocal reaction for periodic time t is derived. Some results about the model with monotone birth function are firstly introduced, and then by constructing two auxiliary equations and squeezing method, the spreading speed for the system with nonmonotone birth function is obtained.展开更多
Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. The...Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. Thermochimique properties of each kinetic parameters reaction are determined. It was found that these parameters have a considerable effect on the thermochemical aspect of the attack reaction. It is known that the process of PN sulphophosphoric acid attack leads to the formation of dihydrate (CaSO4.2H2O: DH). The present work shows the precipitation of other residues their formula depends on factors studied. The increase in concentration leads to the formation of hemihydrate (CaSO4v1/2H2O:HH) beside DH for the low values of% H2SO4 due to the solubility of dihydrate on the etching solution and the precipitation of (Ca (H2PO4)2.2H2O) next of DH for low agitation values because of the lack of turbulence between the liquid phase and the solid phase which favors the precipitation of this latter compound.展开更多
In order to achieve high speed of tufting machine,the oval gear is used as the transmission mechanism between the main shaft and the slave shaft. And then,mathematical model of tufting machine spindle system is establ...In order to achieve high speed of tufting machine,the oval gear is used as the transmission mechanism between the main shaft and the slave shaft. And then,mathematical model of tufting machine spindle system is established by transfer matrix method.Finally,the dynamic reaction force of the connection and the unbalanced response of the joint between the general tufting machine and the improved spindle system are studied by using Matlab numerical simulation. The analysis results showthat when the spindle speed reaches 1 000 r/min, the dynamic reaction force of the improved spindle system at the joint is far less than that of the general tufting machine,and the unbalanced response is reduced from 0. 22 mm to 0. 10 mm.展开更多
目的:探讨青年人平衡能力与手反应速度的相关性。方法:运用智能动态姿态平衡系统的感觉统合测试,测试30例健康青年人的平衡能力,运用抓尺子的方法测试其手反应速度,对所得数据进行统计分析,找出平衡能力与手反应速度的关系。结果:手反...目的:探讨青年人平衡能力与手反应速度的相关性。方法:运用智能动态姿态平衡系统的感觉统合测试,测试30例健康青年人的平衡能力,运用抓尺子的方法测试其手反应速度,对所得数据进行统计分析,找出平衡能力与手反应速度的关系。结果:手反应速度慢的一组的平衡能力明显低于快的一组(74.67±3.786 VS 79.33±4.041,P<0.05),且所有受试者的平衡能力与手反应速度呈正相关,线性回归方程为Y=89.043-0.599X。结论:青年人手反应速度与平衡能力具有相关性,手反应速度越快,平衡能力越好。展开更多
基金Supported by the NSF of China(11171120)Supported by the Doctoral Program of Higher Education of China(20094407110001)Supported by the NSF of Guangdong Province(10151063101000003)
文摘A reaction-diffusion model for a single species with age structure and nonlocal reaction for periodic time t is derived. Some results about the model with monotone birth function are firstly introduced, and then by constructing two auxiliary equations and squeezing method, the spreading speed for the system with nonmonotone birth function is obtained.
文摘Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. Thermochimique properties of each kinetic parameters reaction are determined. It was found that these parameters have a considerable effect on the thermochemical aspect of the attack reaction. It is known that the process of PN sulphophosphoric acid attack leads to the formation of dihydrate (CaSO4.2H2O: DH). The present work shows the precipitation of other residues their formula depends on factors studied. The increase in concentration leads to the formation of hemihydrate (CaSO4v1/2H2O:HH) beside DH for the low values of% H2SO4 due to the solubility of dihydrate on the etching solution and the precipitation of (Ca (H2PO4)2.2H2O) next of DH for low agitation values because of the lack of turbulence between the liquid phase and the solid phase which favors the precipitation of this latter compound.
文摘In order to achieve high speed of tufting machine,the oval gear is used as the transmission mechanism between the main shaft and the slave shaft. And then,mathematical model of tufting machine spindle system is established by transfer matrix method.Finally,the dynamic reaction force of the connection and the unbalanced response of the joint between the general tufting machine and the improved spindle system are studied by using Matlab numerical simulation. The analysis results showthat when the spindle speed reaches 1 000 r/min, the dynamic reaction force of the improved spindle system at the joint is far less than that of the general tufting machine,and the unbalanced response is reduced from 0. 22 mm to 0. 10 mm.
文摘目的:探讨青年人平衡能力与手反应速度的相关性。方法:运用智能动态姿态平衡系统的感觉统合测试,测试30例健康青年人的平衡能力,运用抓尺子的方法测试其手反应速度,对所得数据进行统计分析,找出平衡能力与手反应速度的关系。结果:手反应速度慢的一组的平衡能力明显低于快的一组(74.67±3.786 VS 79.33±4.041,P<0.05),且所有受试者的平衡能力与手反应速度呈正相关,线性回归方程为Y=89.043-0.599X。结论:青年人手反应速度与平衡能力具有相关性,手反应速度越快,平衡能力越好。
