The early stage of exercises is crucial in sports training;however,its physiological mechanism is still unclear.The hemodynamic response was reported to be associated with respiratory exchange.Here,we aimed to explore...The early stage of exercises is crucial in sports training;however,its physiological mechanism is still unclear.The hemodynamic response was reported to be associated with respiratory exchange.Here,we aimed to explore the relationship between oxy-hemoglobin concentration change(HbO_(2))and respiratory exchange ratio(RER)during the early phase of exercises.Sixteen athletes of middle-distance race were selected from Wuhan Institute of Physical Education to conduct intermittent exercises on MERCURY4.0 at 80%VO_(2)peak intensity.Multiple physiological parameters were acquired by use of a near-infrared spectroscopy muscle oxygen monitor,a Cardiopulmonary Function MAX-II and a P-Lar,including HbO_(2),RER and others.A significant correlation was found between RER and HbO_(2)in quadriceps muscle in the thigh during the early phase of exercises.Thus,NIRS is capable of supervising sports training in terms of HbO_(2),which actually acted as an interpreter of RER change.展开更多
A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels wi...A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels with manifold structures. On the basis of multi-tool milling process, the structural design of the manifold side height, microchannel length, width, number, and interval were analyzed. The heat transfer performances of high-aspect-ratio microchannel heat exchangers with two different manifolds were investigated by experiments, and the influencing factors were analyzed. The results indicate that the magnitude of heat transfer area per unit volume dominates the heat transfer performances of plate-type micro heat exchanger, while the velocity distribution between microchannels has little effects on the heat transfer performances.展开更多
The Golden Ratio Theorem, deeply rooted in fractal mathematics, presents a pioneering perspective on deciphering complex systems. It draws a profound connection between the principles of interchangeability, self-simil...The Golden Ratio Theorem, deeply rooted in fractal mathematics, presents a pioneering perspective on deciphering complex systems. It draws a profound connection between the principles of interchangeability, self-similarity, and the mathematical elegance of the Golden Ratio. This research unravels a unique methodological paradigm, emphasizing the omnipresence of the Golden Ratio in shaping system dynamics. The novelty of this study stems from its detailed exposition of self-similarity and interchangeability, transforming them from mere abstract notions into actionable, concrete insights. By highlighting the fractal nature of the Golden Ratio, the implications of these revelations become far-reaching, heralding new avenues for both theoretical advancements and pragmatic applications across a spectrum of scientific disciplines.展开更多
Numerical analysis was performed to investigate flow and heat transfer characteristics in spiral coiled tube heat exchanger. Radius of curvature of the spiral coiled tube was gradually increased as total rotating angl...Numerical analysis was performed to investigate flow and heat transfer characteristics in spiral coiled tube heat exchanger. Radius of curvature of the spiral coiled tube was gradually increased as total rotating angle reached 12π. As the varying radius of curvature became a dominant flow parameter, three-dimensional flow analysis was performed to this flow together with different Reynolds numbers while constant wall heat flux condition was set in thermal field. From the analysis, centrifugal force due to curvature effect is found to have significant role in behavior of pressure drop and heat transfer. The centrifugal force enhances pressure drop and heat transfer to have generally higher values in the spiral coiled tube than those in the straight tube. Even then, friction factor and Nusselt number are found to follow the proportionality with square root of the Dean number. Individual effect of flow parameters of Reynolds number and curvature ratio was investigated and effect of Reynolds number is found to be stronger than that of curvature effect.展开更多
In order to improve the performance of vehicle radiators, a two-dimensional heat transfer steady-state model of the radiator was set up. The influence of the structural parameters (axial ratio) of the heat exchange tu...In order to improve the performance of vehicle radiators, a two-dimensional heat transfer steady-state model of the radiator was set up. The influence of the structural parameters (axial ratio) of the heat exchange tube on the windward side on the heat transfer performance of the radiator was studied. With the increase of the axial ratio of the heat exchange tube on the windward side, the heat exchange capacity of the heat exchange tube surface slightly decreases. The heat exchange area increases significantly, which increases the total heat exchange of the radiator and improves the heat transfer performance of the radiator. When the axial ratio increases from 1.0 to 2.0, the average surface heat transfer capacity decreases from 5664.16</span><span style="font-family:""> </span><span style="font-family:Verdana;">W/m<sup>2</sup> to 5623.57</span><span style="font-family:""> </span><span style="font-family:Verdana;">W/m<sup>2</sup>.展开更多
The scope of this paper is to contribute to the question of delisting (both voluntary and involuntary), with particular emphasis on the initial conditions leading up to the Initial Public Offering (IPO) of the firms. ...The scope of this paper is to contribute to the question of delisting (both voluntary and involuntary), with particular emphasis on the initial conditions leading up to the Initial Public Offering (IPO) of the firms. The case of Athens Stock Exchange (ASE) is examined, specifically the IPOs of years 1996-2004 and their subsequent performance (delisting or not) till the end of 2017. We find that the probability of delisting is positively associated with the size of the issuance and the degree of earnings’ manipulation and negatively associated with audit quality, information transparency, and market timing. The effects of audit quality, size of issuance, and earnings’ manipulation are accentuated in instances of voluntary delisting while the effect of market timing is more clearly pronounced in instances of involuntary delisting. Our results are robust to a number of confounding factors including size, profitability, leverage, liquidity, growth options, and corporate governance. Our work is not replication of existing studies;in addition, we choose ASE as in that capital market there were many delistings the last two decades.展开更多
基金We would like to acknowledge the support from National Science Funds of China(30770554).
文摘The early stage of exercises is crucial in sports training;however,its physiological mechanism is still unclear.The hemodynamic response was reported to be associated with respiratory exchange.Here,we aimed to explore the relationship between oxy-hemoglobin concentration change(HbO_(2))and respiratory exchange ratio(RER)during the early phase of exercises.Sixteen athletes of middle-distance race were selected from Wuhan Institute of Physical Education to conduct intermittent exercises on MERCURY4.0 at 80%VO_(2)peak intensity.Multiple physiological parameters were acquired by use of a near-infrared spectroscopy muscle oxygen monitor,a Cardiopulmonary Function MAX-II and a P-Lar,including HbO_(2),RER and others.A significant correlation was found between RER and HbO_(2)in quadriceps muscle in the thigh during the early phase of exercises.Thus,NIRS is capable of supervising sports training in terms of HbO_(2),which actually acted as an interpreter of RER change.
基金Projects(50675070 50805052) supported by the National Nature Science Foundation of China+1 种基金Projects(07118064 8451064101000320) supported by the Natural Science Foundation of Guangdong Province
文摘A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels with manifold structures. On the basis of multi-tool milling process, the structural design of the manifold side height, microchannel length, width, number, and interval were analyzed. The heat transfer performances of high-aspect-ratio microchannel heat exchangers with two different manifolds were investigated by experiments, and the influencing factors were analyzed. The results indicate that the magnitude of heat transfer area per unit volume dominates the heat transfer performances of plate-type micro heat exchanger, while the velocity distribution between microchannels has little effects on the heat transfer performances.
文摘The Golden Ratio Theorem, deeply rooted in fractal mathematics, presents a pioneering perspective on deciphering complex systems. It draws a profound connection between the principles of interchangeability, self-similarity, and the mathematical elegance of the Golden Ratio. This research unravels a unique methodological paradigm, emphasizing the omnipresence of the Golden Ratio in shaping system dynamics. The novelty of this study stems from its detailed exposition of self-similarity and interchangeability, transforming them from mere abstract notions into actionable, concrete insights. By highlighting the fractal nature of the Golden Ratio, the implications of these revelations become far-reaching, heralding new avenues for both theoretical advancements and pragmatic applications across a spectrum of scientific disciplines.
基金supported by the Second Stage of Brain Korea 21 Projects,Korea
文摘Numerical analysis was performed to investigate flow and heat transfer characteristics in spiral coiled tube heat exchanger. Radius of curvature of the spiral coiled tube was gradually increased as total rotating angle reached 12π. As the varying radius of curvature became a dominant flow parameter, three-dimensional flow analysis was performed to this flow together with different Reynolds numbers while constant wall heat flux condition was set in thermal field. From the analysis, centrifugal force due to curvature effect is found to have significant role in behavior of pressure drop and heat transfer. The centrifugal force enhances pressure drop and heat transfer to have generally higher values in the spiral coiled tube than those in the straight tube. Even then, friction factor and Nusselt number are found to follow the proportionality with square root of the Dean number. Individual effect of flow parameters of Reynolds number and curvature ratio was investigated and effect of Reynolds number is found to be stronger than that of curvature effect.
文摘In order to improve the performance of vehicle radiators, a two-dimensional heat transfer steady-state model of the radiator was set up. The influence of the structural parameters (axial ratio) of the heat exchange tube on the windward side on the heat transfer performance of the radiator was studied. With the increase of the axial ratio of the heat exchange tube on the windward side, the heat exchange capacity of the heat exchange tube surface slightly decreases. The heat exchange area increases significantly, which increases the total heat exchange of the radiator and improves the heat transfer performance of the radiator. When the axial ratio increases from 1.0 to 2.0, the average surface heat transfer capacity decreases from 5664.16</span><span style="font-family:""> </span><span style="font-family:Verdana;">W/m<sup>2</sup> to 5623.57</span><span style="font-family:""> </span><span style="font-family:Verdana;">W/m<sup>2</sup>.
文摘The scope of this paper is to contribute to the question of delisting (both voluntary and involuntary), with particular emphasis on the initial conditions leading up to the Initial Public Offering (IPO) of the firms. The case of Athens Stock Exchange (ASE) is examined, specifically the IPOs of years 1996-2004 and their subsequent performance (delisting or not) till the end of 2017. We find that the probability of delisting is positively associated with the size of the issuance and the degree of earnings’ manipulation and negatively associated with audit quality, information transparency, and market timing. The effects of audit quality, size of issuance, and earnings’ manipulation are accentuated in instances of voluntary delisting while the effect of market timing is more clearly pronounced in instances of involuntary delisting. Our results are robust to a number of confounding factors including size, profitability, leverage, liquidity, growth options, and corporate governance. Our work is not replication of existing studies;in addition, we choose ASE as in that capital market there were many delistings the last two decades.
