The Doppler effect can be defined as the frequency shift suffered by a wave phenomenon, when there is a difference in relative speed between the waves generated and their source. We know that it occurs in the case of ...The Doppler effect can be defined as the frequency shift suffered by a wave phenomenon, when there is a difference in relative speed between the waves generated and their source. We know that it occurs in the case of mechanical and electromagnetic waves. We propose to generalize the Doppler effect to the case of frequency changes of certain oscillatory variables in biology before and after puberty, starting from the basis that a metabolically accelerated system is equivalent to a mechanically accelerated system. We then established the following objectives: To verify if there is an average difference in heart and respiratory rates, before and after puberty. To verify the association of these frequency differences with the metabolic activity estimated as basal metabolic rate or BMR. We studied heart and respiratory rate data from healthy people of both sexes, verifying the frequency distribution before and after puberty. We also study the relationship of the frequency distribution with the evolution of the basal metabolic rate throughout life. Analysis of the results shows that the highest heart and respiratory rates occur before puberty, while the lowest rates occur after puberty. A high correlation of the evolution of the variables studied with the evolution of the metabolic acceleration of the system throughout life is also evident. Taking into account that a mechanically accelerated system is equivalent to a metabolically accelerated system, we can conclude that the frequency distribution found is the expression of a generalization of the Doppler effect in the case of biological physical systems.展开更多
Forces acting on abrasive in the process of speeding up have been analyzed. Motion differential equation of abrasive in a pipeline and nozzle has been given, respectively. Mechanisms of abrasive particles accelerated ...Forces acting on abrasive in the process of speeding up have been analyzed. Motion differential equation of abrasive in a pipeline and nozzle has been given, respectively. Mechanisms of abrasive particles accelerated in a premixed abrasive jet has been analyzed. The study shows that driven by high-pressure water, velocity of an abrasive is near to velocity of water in pipeline through the acceleration distance. In the taper section of a nozzle, water and abrasive particles are greatly accelerated at the same time. But velocity of an abrasive always lags behind velocity of water. A premixed abrasive jet cutting system has been introduced. The structure and working principles of the system have been given. The system is an assembly of abrasive screening and filling. By use of the premixed abrasive jet cutting system established, cutting experiments have been made to test the main parameters which influence the cutting performances such as working pressure, standoff and traverse velocity, and the nozzle diameter affecting cutting chink width.展开更多
文摘The Doppler effect can be defined as the frequency shift suffered by a wave phenomenon, when there is a difference in relative speed between the waves generated and their source. We know that it occurs in the case of mechanical and electromagnetic waves. We propose to generalize the Doppler effect to the case of frequency changes of certain oscillatory variables in biology before and after puberty, starting from the basis that a metabolically accelerated system is equivalent to a mechanically accelerated system. We then established the following objectives: To verify if there is an average difference in heart and respiratory rates, before and after puberty. To verify the association of these frequency differences with the metabolic activity estimated as basal metabolic rate or BMR. We studied heart and respiratory rate data from healthy people of both sexes, verifying the frequency distribution before and after puberty. We also study the relationship of the frequency distribution with the evolution of the basal metabolic rate throughout life. Analysis of the results shows that the highest heart and respiratory rates occur before puberty, while the lowest rates occur after puberty. A high correlation of the evolution of the variables studied with the evolution of the metabolic acceleration of the system throughout life is also evident. Taking into account that a mechanically accelerated system is equivalent to a metabolically accelerated system, we can conclude that the frequency distribution found is the expression of a generalization of the Doppler effect in the case of biological physical systems.
基金supported by the Natural Science Foundation of Anhui Province under Grant No.KJ2009A092
文摘Forces acting on abrasive in the process of speeding up have been analyzed. Motion differential equation of abrasive in a pipeline and nozzle has been given, respectively. Mechanisms of abrasive particles accelerated in a premixed abrasive jet has been analyzed. The study shows that driven by high-pressure water, velocity of an abrasive is near to velocity of water in pipeline through the acceleration distance. In the taper section of a nozzle, water and abrasive particles are greatly accelerated at the same time. But velocity of an abrasive always lags behind velocity of water. A premixed abrasive jet cutting system has been introduced. The structure and working principles of the system have been given. The system is an assembly of abrasive screening and filling. By use of the premixed abrasive jet cutting system established, cutting experiments have been made to test the main parameters which influence the cutting performances such as working pressure, standoff and traverse velocity, and the nozzle diameter affecting cutting chink width.
