The size of initial bubbles is an important factor to the developed bubble size distribution in a gas-liquid contactor. A liquid cross-flow over a sparger can produce smaller bubbles, and hereby enhance the performanc...The size of initial bubbles is an important factor to the developed bubble size distribution in a gas-liquid contactor. A liquid cross-flow over a sparger can produce smaller bubbles, and hereby enhance the performance of contactor. A one stage model by balancing the forces acting on a growing bubble was developed to describe the formation of the bubble from an orifice exposed to liquid cross-flow. The prediction with this model agrees with the experimental data available in the literatures, and show that orifice size strongly affects the bubble size. It is showed that the shear-lift force, inertia force, surface tension force and buoyancy force are major forces, and a simplified mathematical model was developed, and the detachment bubble diameter can be predicted with accuracy of <±21%.展开更多
Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h： to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class curren...Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h： to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class current collection performance evaluation methods that have been developed and demonstrated by Korea. Specifically, this paper reports details of the video-based monitoring techniques that have been adopted to inspect the stability of overhead contact line （OCL） components at 400 km.h-1 without direct contact with any components of the power supply system. Unlike conventional OCL monitoring systems, which detect contact wire positions using either laser sensors or line cameras, the developed system measures parameters in the active state by video data. According to experimental results that were obtained at a field-test site established at a commercial line, it is claimed that the proposed mea- surement system is capable of effectively measuring OCL parameters.展开更多
Radio frequency identification(RFID) is a new type of non-contact automatic identification technology.Due to its low energy consumption,low cost,and its adaptability to harsh environments,it has been applied to many f...Radio frequency identification(RFID) is a new type of non-contact automatic identification technology.Due to its low energy consumption,low cost,and its adaptability to harsh environments,it has been applied to many fields.In the RFID systems,data collision is inevitable when the reader sends a communication request and multiple tags respond with simultaneous data transmission.Data collision is prone to causing problems such as:identification delay,spectrum resource waste,a decreased system throughput rate,etc.Therefore,an efficient,stable anti-collision protocol is crucial for RFID systems.This research analysed the current research into RFID anticollision protocols and summarised means for its improvement through the mechanism of implementation of different types anticollision protocols.Finally,a new direction is proposed for the future development of RFID anti-collision protocol systems.展开更多
Measurements of topography at the segment of bifurcation between the South Channel and North Channel in the Yangtze Estuary were conducted, and a new type of subaqueous dune was discovered. This structure, newly defin...Measurements of topography at the segment of bifurcation between the South Channel and North Channel in the Yangtze Estuary were conducted, and a new type of subaqueous dune was discovered. This structure, newly defined as a catenary-bead dune, consists of a catenary dune and its associated elliptical pit bedform. Based on this finding, the nomenclature of "morphology of dune associated with accompanying bedform" is first proposed. The measured data indicate a mean height and wavelength of 1.29 m and 31.89 m, respectively; wavelength/height ratio(L/H) of 14 to 56; and elliptical pits of mean and maximum depth 0.98 m and 1.98 m, respectively. Flow information was obtained using an Acoustic Doppler Current Profile(ADCP), and the bed material components were gathered with a bottom sampler. The results show mean flood and ebb velocities of 0.27 and 0.78 m s?1, respectively, with shorter duration of flood tide than ebb tide. The silt, very fine sand, and fine sand fractions were within the ranges 21.6–23.4%, 28.2–32.2%, and 39.7–41.6%, respectively, revealing complex bed material composition. Water depth at the study site varies from 13 to 17 m. This finding will enrich the study of dunes and provide important data for geomorphological research. Moreover, the results are significant for engineering applications to estuaries.展开更多
In this paper,a "macroscopic-scale" numerical method for drop oscillation in AC electrowetting is presented.The method is based on a high-fidelity moving mesh interface tracking(MMIT) approach and a "mi...In this paper,a "macroscopic-scale" numerical method for drop oscillation in AC electrowetting is presented.The method is based on a high-fidelity moving mesh interface tracking(MMIT) approach and a "microscopic model" for the moving contact line.The contact line model developed by Ren et al.[Phys Fluids,2010,22:102103] is used in the simulation.To determine the slip length in this model,we propose a calibration procedure using the experimental data of drop spreading in DC electrowetting.In the simulation,the frequency of input AC voltage varies in a certain range while the root-mean-square value remains fixed.The numerical simulation is validated against the experiment and it shows that the predicted resonance frequencies for different oscillation modes agree reasonably well with the experiment.The origins of discrepancy between simulation and experiment are analyzed in the paper.Further investigation is also conducted by including the contact angle hysteresis into the contact line model to account for the "stick-slip" behavior.A noticeable improvement on the prediction of resonance frequencies is achieved by using the hysteresis model.展开更多
Accurate assessment of the probability of success in an aggressive confrontation with a conspecific is critical to the survival and fitness of the individuals. Various game theory models have examined these assessment...Accurate assessment of the probability of success in an aggressive confrontation with a conspecific is critical to the survival and fitness of the individuals. Various game theory models have examined these assessment strategies under the assumption that contests should favor the animal with the greater resource-holding potential （RHP）, body size typically being the proxy. Mutual assessment asserts that an individual can assess their own RHP relative to their opponent, allowing the inferior animal the chance to flee before incurring unnecessary costs. The model of self-determined persistence, however, assumes that an individual will fight to a set personal threshold, independ- ent of their opponent＇s RHP. Both models have been repeatedly tested using size as a proxy for RHP, with neither receiving unambiguous support. Here we present both morphological and neuro- physiological data from size-matched and mismatched stalk-eyed fly fights. We discovered differ- ing fighting strategies between winners and losers. Winners readily escalated encounters to higher intensity and physical contact and engaged in less low-intensity, posturing behaviors compared with losers. Although these fighting strategies were largely independent of size, they were associ- ated with elevated levels of 5-HT. Understanding the neurophysiological factors responsible for mediating the motivational state of opponents could help resolve the inconsistencies seen in cur- rent game theory models. Therefore, we contend that current studies using only size as a proxy for RHP may be inadequate in determining the intricacies of fighting ability and that future studies investigating assessment strategies and contest outcome should include neurophysiological data.展开更多
基金Supported by the National Natural Science Foundation of China （20736009）
文摘The size of initial bubbles is an important factor to the developed bubble size distribution in a gas-liquid contactor. A liquid cross-flow over a sparger can produce smaller bubbles, and hereby enhance the performance of contactor. A one stage model by balancing the forces acting on a growing bubble was developed to describe the formation of the bubble from an orifice exposed to liquid cross-flow. The prediction with this model agrees with the experimental data available in the literatures, and show that orifice size strongly affects the bubble size. It is showed that the shear-lift force, inertia force, surface tension force and buoyancy force are major forces, and a simplified mathematical model was developed, and the detachment bubble diameter can be predicted with accuracy of <±21%.
文摘Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h： to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class current collection performance evaluation methods that have been developed and demonstrated by Korea. Specifically, this paper reports details of the video-based monitoring techniques that have been adopted to inspect the stability of overhead contact line （OCL） components at 400 km.h-1 without direct contact with any components of the power supply system. Unlike conventional OCL monitoring systems, which detect contact wire positions using either laser sensors or line cameras, the developed system measures parameters in the active state by video data. According to experimental results that were obtained at a field-test site established at a commercial line, it is claimed that the proposed mea- surement system is capable of effectively measuring OCL parameters.
基金The authors would like to thank the reviewers for their detailed reviews and constructive comments, which have helped improve the quality of this paper. This paper is supported by the National Natural Science Founda- tion of China （No. 61371092）, the Doctoral Fund of Ministry of Education of China （No.20130061120062）, and the China Postdoc- toral Science Foundation （No. 2014M551184）.
文摘Radio frequency identification(RFID) is a new type of non-contact automatic identification technology.Due to its low energy consumption,low cost,and its adaptability to harsh environments,it has been applied to many fields.In the RFID systems,data collision is inevitable when the reader sends a communication request and multiple tags respond with simultaneous data transmission.Data collision is prone to causing problems such as:identification delay,spectrum resource waste,a decreased system throughput rate,etc.Therefore,an efficient,stable anti-collision protocol is crucial for RFID systems.This research analysed the current research into RFID anticollision protocols and summarised means for its improvement through the mechanism of implementation of different types anticollision protocols.Finally,a new direction is proposed for the future development of RFID anti-collision protocol systems.
基金the National Natural Science Foundation of China (Grant No. 41476075)
文摘Measurements of topography at the segment of bifurcation between the South Channel and North Channel in the Yangtze Estuary were conducted, and a new type of subaqueous dune was discovered. This structure, newly defined as a catenary-bead dune, consists of a catenary dune and its associated elliptical pit bedform. Based on this finding, the nomenclature of "morphology of dune associated with accompanying bedform" is first proposed. The measured data indicate a mean height and wavelength of 1.29 m and 31.89 m, respectively; wavelength/height ratio(L/H) of 14 to 56; and elliptical pits of mean and maximum depth 0.98 m and 1.98 m, respectively. Flow information was obtained using an Acoustic Doppler Current Profile(ADCP), and the bed material components were gathered with a bottom sampler. The results show mean flood and ebb velocities of 0.27 and 0.78 m s?1, respectively, with shorter duration of flood tide than ebb tide. The silt, very fine sand, and fine sand fractions were within the ranges 21.6–23.4%, 28.2–32.2%, and 39.7–41.6%, respectively, revealing complex bed material composition. Water depth at the study site varies from 13 to 17 m. This finding will enrich the study of dunes and provide important data for geomorphological research. Moreover, the results are significant for engineering applications to estuaries.
基金supported by the Chinese Academy of Sciences(Grant Nos. KJCX-SW-L08,KJCX2-YW-H18 and KJCX3-SYW-S01)the National Basic Research Program of China(Grant No.2007CB814803)the National Natural Science Foundation of China(Grant Nos.10732090,10872201 and 11023001)
文摘In this paper,a "macroscopic-scale" numerical method for drop oscillation in AC electrowetting is presented.The method is based on a high-fidelity moving mesh interface tracking(MMIT) approach and a "microscopic model" for the moving contact line.The contact line model developed by Ren et al.[Phys Fluids,2010,22:102103] is used in the simulation.To determine the slip length in this model,we propose a calibration procedure using the experimental data of drop spreading in DC electrowetting.In the simulation,the frequency of input AC voltage varies in a certain range while the root-mean-square value remains fixed.The numerical simulation is validated against the experiment and it shows that the predicted resonance frequencies for different oscillation modes agree reasonably well with the experiment.The origins of discrepancy between simulation and experiment are analyzed in the paper.Further investigation is also conducted by including the contact angle hysteresis into the contact line model to account for the "stick-slip" behavior.A noticeable improvement on the prediction of resonance frequencies is achieved by using the hysteresis model.
文摘Accurate assessment of the probability of success in an aggressive confrontation with a conspecific is critical to the survival and fitness of the individuals. Various game theory models have examined these assessment strategies under the assumption that contests should favor the animal with the greater resource-holding potential （RHP）, body size typically being the proxy. Mutual assessment asserts that an individual can assess their own RHP relative to their opponent, allowing the inferior animal the chance to flee before incurring unnecessary costs. The model of self-determined persistence, however, assumes that an individual will fight to a set personal threshold, independ- ent of their opponent＇s RHP. Both models have been repeatedly tested using size as a proxy for RHP, with neither receiving unambiguous support. Here we present both morphological and neuro- physiological data from size-matched and mismatched stalk-eyed fly fights. We discovered differ- ing fighting strategies between winners and losers. Winners readily escalated encounters to higher intensity and physical contact and engaged in less low-intensity, posturing behaviors compared with losers. Although these fighting strategies were largely independent of size, they were associ- ated with elevated levels of 5-HT. Understanding the neurophysiological factors responsible for mediating the motivational state of opponents could help resolve the inconsistencies seen in cur- rent game theory models. Therefore, we contend that current studies using only size as a proxy for RHP may be inadequate in determining the intricacies of fighting ability and that future studies investigating assessment strategies and contest outcome should include neurophysiological data.
