The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel pattern.In this paper,the development of channel pattern in the process of r...The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel pattern.In this paper,the development of channel pattern in the process of reformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis- charge and discharge process are comprehensively analyzed according to the experimental data.It was found that the channel would be widened as the river slope or discharge increased and grain s...展开更多
Based on experimental data and theory,by means of simplified discharge durations in a small flume,the influence of discharge process on channel morphology and channel pattern was analyzed in this paper.It was conclude...Based on experimental data and theory,by means of simplified discharge durations in a small flume,the influence of discharge process on channel morphology and channel pattern was analyzed in this paper.It was concluded that on the same original channel,different discharge and channel conditions would end with different river morphology,including thalwegs and radius of bends.Different discharge process resulted in two kinds of change:tiny change in the process of"big-small-big"and distinct change in the process of"small-big-small".Flood discharge duration was verified to be the main cause in the discharge process.Proper discharge process will change the morphologies of river,even can led to channel pattern transformation.The influences based on the relationship between the flow and the channel itself,including slope and riverbed constitution.Although not be a main cause,original channel morphology may influence its final channel pattern.Neglecting the influence of channel itself will hamper the understanding of channel patterns.展开更多
Machining experiment of micro channel structure with 6:4 brass was carried out by shaping process using a single crystal diamond tool. FEM simulation using solid cantilever beam model was analyzed. In result of experi...Machining experiment of micro channel structure with 6:4 brass was carried out by shaping process using a single crystal diamond tool. FEM simulation using solid cantilever beam model was analyzed. In result of experiment, tool deflection is observed as machining characteristics through result of experiments such as surface roughness, cutting force and burr formations. And the influence of tool deflection is experimentally proved.展开更多
River channel pattern transformation is dealt with in a broad background of suspended sediment concentration, varying from low, medium, high to hyperconcentration. Based on data from about 100 alluvial rivers in China...River channel pattern transformation is dealt with in a broad background of suspended sediment concentration, varying from low, medium, high to hyperconcentration. Based on data from about 100 alluvial rivers in China, suspended sediment transport rate has been plotted against mean annual water discharge, showing that all points can be divided into four belts by three straight lines, as stable braided pattern, meandering pattern with ordinary sediment concentrations, wandering braided pattern, and meandering pattern with hyperconcentration of sediment. This picture of channel pattern transformation can be well explained by the law of the water flow’s energy expenditure varying with its sediment concentration. The energy expenditure increases with sediment concentration, reaching a maximum, then declines. Rivers falling in different ranges of sediment concentrations adjust their own energy expenditure in different manners, leading to occurrence of different channel patterns.展开更多
So far most of the researchers regard river channel pattern formation as a deterministic problem, but a few begin to treat it as a probabilistic one. For the study of the areal distribution of river channel patterns, ...So far most of the researchers regard river channel pattern formation as a deterministic problem, but a few begin to treat it as a probabilistic one. For the study of the areal distribution of river channel patterns, we put forward the concept of river channel pattern frequency which can be defined展开更多
Since the geoecological approach was widely introduced into geomorphologicalstudies, a new trend characterized by this approach has been formed in thegeomorphological research frontier. Starkel has applied the concept...Since the geoecological approach was widely introduced into geomorphologicalstudies, a new trend characterized by this approach has been formed in thegeomorphological research frontier. Starkel has applied the concept of river drainagebasin geoecosystem to the study of paleo-patterns of rivers and concluded that thechanges in the river channel patterns can be regarded as the expression of展开更多
It is generally accepted by research workers both in China and abroad at present that wandering braided river channel pattern forms under such conditions that the sediment transportation is not in equilibrium and a st...It is generally accepted by research workers both in China and abroad at present that wandering braided river channel pattern forms under such conditions that the sediment transportation is not in equilibrium and a strong aggradation occurs. Sometimes a展开更多
Along with the introduction of the concept of dual-channel communication,we utilized the finite-difference time-domain（FDTD） method to simulate and measure the radiation pattern under certain plasma densities and pl...Along with the introduction of the concept of dual-channel communication,we utilized the finite-difference time-domain（FDTD） method to simulate and measure the radiation pattern under certain plasma densities and plasma collision frequencies.Results show that under certain settings,the radiation pattern of a plasma antenna resembles that of a metallic antenna.In contrast to a metallic antenna,a plasma antenna possesses other functionalities,such as dynamic reconfiguration and digital controllability.The data from simulation are similar to the measurement results,indicating that column plasma antenna can realize dual-channel communication.This work confirms the viability of realizing dual-channel communication by column plasma antenna,which adds a new but promising method for modern intelligent communication.展开更多
Abstract-Common spatial pattern （CSP） algorithm is a successful tool in feature estimate of brain-computer interface （BCI）. However, CSP is sensitive to outlier and may result in poor outcomes since it is based on...Abstract-Common spatial pattern （CSP） algorithm is a successful tool in feature estimate of brain-computer interface （BCI）. However, CSP is sensitive to outlier and may result in poor outcomes since it is based on pooling the covariance matrices of trials. In this paper, we propose a simple yet effective approach, named common spatial pattern ensemble （CSPE） classifier, to improve CSP performance. Through division of recording channels, multiple CSP filters are constructed. By projection, log-operation, and subtraction on the original signal, an ensemble classifier, majority voting, is achieved and outlier contaminations are alleviated. Experiment results demonstrate that the proposed CSPE classifier is robust to various artifacts and can achieve an average accuracy of 83.02%.展开更多
基金Supported by National Key Basic Research and Development Program(973 Program) (2003CB415205),the National Natural Science Foundation of China(50479036)
文摘The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel pattern.In this paper,the development of channel pattern in the process of reformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis- charge and discharge process are comprehensively analyzed according to the experimental data.It was found that the channel would be widened as the river slope or discharge increased and grain s...
基金Foundation item:Under the auspices of the Major State Basic Research Development Program of China(973 Program)(No.2003 CB415205)the National Natural Science Foundation of China(No.50479036)
文摘Based on experimental data and theory,by means of simplified discharge durations in a small flume,the influence of discharge process on channel morphology and channel pattern was analyzed in this paper.It was concluded that on the same original channel,different discharge and channel conditions would end with different river morphology,including thalwegs and radius of bends.Different discharge process resulted in two kinds of change:tiny change in the process of"big-small-big"and distinct change in the process of"small-big-small".Flood discharge duration was verified to be the main cause in the discharge process.Proper discharge process will change the morphologies of river,even can led to channel pattern transformation.The influences based on the relationship between the flow and the channel itself,including slope and riverbed constitution.Although not be a main cause,original channel morphology may influence its final channel pattern.Neglecting the influence of channel itself will hamper the understanding of channel patterns.
文摘Machining experiment of micro channel structure with 6:4 brass was carried out by shaping process using a single crystal diamond tool. FEM simulation using solid cantilever beam model was analyzed. In result of experiment, tool deflection is observed as machining characteristics through result of experiments such as surface roughness, cutting force and burr formations. And the influence of tool deflection is experimentally proved.
文摘River channel pattern transformation is dealt with in a broad background of suspended sediment concentration, varying from low, medium, high to hyperconcentration. Based on data from about 100 alluvial rivers in China, suspended sediment transport rate has been plotted against mean annual water discharge, showing that all points can be divided into four belts by three straight lines, as stable braided pattern, meandering pattern with ordinary sediment concentrations, wandering braided pattern, and meandering pattern with hyperconcentration of sediment. This picture of channel pattern transformation can be well explained by the law of the water flow’s energy expenditure varying with its sediment concentration. The energy expenditure increases with sediment concentration, reaching a maximum, then declines. Rivers falling in different ranges of sediment concentrations adjust their own energy expenditure in different manners, leading to occurrence of different channel patterns.
基金Project supported by the Youth Scientific Foundation of Academia Sinica.
文摘So far most of the researchers regard river channel pattern formation as a deterministic problem, but a few begin to treat it as a probabilistic one. For the study of the areal distribution of river channel patterns, we put forward the concept of river channel pattern frequency which can be defined
基金Project supported by the National Natural Science Foundation of China.
文摘Since the geoecological approach was widely introduced into geomorphologicalstudies, a new trend characterized by this approach has been formed in thegeomorphological research frontier. Starkel has applied the concept of river drainagebasin geoecosystem to the study of paleo-patterns of rivers and concluded that thechanges in the river channel patterns can be regarded as the expression of
基金Project supported by the National Natural Science Foundation of China
文摘It is generally accepted by research workers both in China and abroad at present that wandering braided river channel pattern forms under such conditions that the sediment transportation is not in equilibrium and a strong aggradation occurs. Sometimes a
文摘Along with the introduction of the concept of dual-channel communication,we utilized the finite-difference time-domain（FDTD） method to simulate and measure the radiation pattern under certain plasma densities and plasma collision frequencies.Results show that under certain settings,the radiation pattern of a plasma antenna resembles that of a metallic antenna.In contrast to a metallic antenna,a plasma antenna possesses other functionalities,such as dynamic reconfiguration and digital controllability.The data from simulation are similar to the measurement results,indicating that column plasma antenna can realize dual-channel communication.This work confirms the viability of realizing dual-channel communication by column plasma antenna,which adds a new but promising method for modern intelligent communication.
基金supported by the National Natural Science Foundation of China under Grant No. 30525030, 60701015, and 60736029.
文摘Abstract-Common spatial pattern （CSP） algorithm is a successful tool in feature estimate of brain-computer interface （BCI）. However, CSP is sensitive to outlier and may result in poor outcomes since it is based on pooling the covariance matrices of trials. In this paper, we propose a simple yet effective approach, named common spatial pattern ensemble （CSPE） classifier, to improve CSP performance. Through division of recording channels, multiple CSP filters are constructed. By projection, log-operation, and subtraction on the original signal, an ensemble classifier, majority voting, is achieved and outlier contaminations are alleviated. Experiment results demonstrate that the proposed CSPE classifier is robust to various artifacts and can achieve an average accuracy of 83.02%.
