This paper presents a novel digital dual-loop control scheme of the PWM(PUlse width modulate)inverter. Deadbeat control technique are employed to enhance the performance. Half switching period delayed sampling and con...This paper presents a novel digital dual-loop control scheme of the PWM(PUlse width modulate)inverter. Deadbeat control technique are employed to enhance the performance. Half switching period delayed sampling and control timing strategy is used to improve the system dynamic response. Simulation and experimental results presented in the paper verified the validity of the proposed control scheme.展开更多
A modified Rushton impeller with two circular covering-plates mounted on the upper and lower sides of the blades was designed.There are gaps between the plates and the blades.The turbulent hydrodynamics was analyzed b...A modified Rushton impeller with two circular covering-plates mounted on the upper and lower sides of the blades was designed.There are gaps between the plates and the blades.The turbulent hydrodynamics was analyzed by the computational fluid dynamics(CFD) method.Firstly,the reliability of the numerical model and simulation method was verified by comparing with the experimental results from literature.Subsequently,the power consumption,flow pattern,mean velocity and mixing time of the covering-plate Rushton impeller(RT-C) were studied and compared with the standard Rushton impeller(RT) operated under the same conditions.Results show that the power consumption can be decreased about 18%.Compared with the almost unchanged flow field in the lower stirred tank,the mean velocity was increased at the upper half of the stirred tank.And in the impeller region,the mean axial and radial velocities were increased,the mean tangential velocity was decreased.In addition,the average mixing time of RT-C was shortened about 4.14% than the counterpart of RT.The conclusions obtained here indicated that RT-C has a more effective mixing performance and it can be used as an alternative of RT in the process industries.展开更多
Medialization has become like digitalization, rationalization, dynamization, globalization, pluralization, hybridization, and differentialization and is one of the buzzwords of modern Western industrialized societies,...Medialization has become like digitalization, rationalization, dynamization, globalization, pluralization, hybridization, and differentialization and is one of the buzzwords of modern Western industrialized societies, which are all together essentially responsible for structural change in communication. Medialization means the adaption of producers to media logics, media formats, and media routines ＆ workflows. There are consequently and logically influences because of the dynamic process of medialization to legal discourse and genres, law, media, and social power. It has to be discussed if the logics, data formats, and routines ＆ workflows of new media and information and communication technologies （ICTs） like social media are creating also a new generation of genres and novel form of legal discourses. Also, if social media will replace or complete old classic media （law of Riepl）, the question of the relevance of law concerning new ＆ social media has to be answered in close future. Lastly, if to the fore of social power, these new novel resources are actually framing for problem-based inquiries in law. There are big chances but also serious risks in cyberworld, their realities, and dangers. There actually exists an urgent call of action to theory building, development of methodologies, and empirical research.展开更多
Pulsatile flow of blood in a blood vessel having time-dependent shape （diameter） is inves-tigated numerically in order to understand some important physiological phenomena in arteries. A smooth axi-symmetric cosine ...Pulsatile flow of blood in a blood vessel having time-dependent shape （diameter） is inves-tigated numerically in order to understand some important physiological phenomena in arteries. A smooth axi-symmetric cosine shaped constriction is considered. To mimic the realistic situation as far as possible, viscosity of blood is taken to be non-uniform, a shear-thinning viscosity model is considered and a physiologically relevant pulsatile flow is introduced. Taking advantage of axi-symmetry in the proposed problem, the stream function-vorticity formulation is used to solve the governing equations for blood flow. Effect of different parameters associated with the problem on the flow pattern has been investigated and disparities from the Newtonian case are discussed in detail.展开更多
文摘This paper presents a novel digital dual-loop control scheme of the PWM(PUlse width modulate)inverter. Deadbeat control technique are employed to enhance the performance. Half switching period delayed sampling and control timing strategy is used to improve the system dynamic response. Simulation and experimental results presented in the paper verified the validity of the proposed control scheme.
基金Supported by the Key Development Foundation of Shandong province(2016GGX103035)
文摘A modified Rushton impeller with two circular covering-plates mounted on the upper and lower sides of the blades was designed.There are gaps between the plates and the blades.The turbulent hydrodynamics was analyzed by the computational fluid dynamics(CFD) method.Firstly,the reliability of the numerical model and simulation method was verified by comparing with the experimental results from literature.Subsequently,the power consumption,flow pattern,mean velocity and mixing time of the covering-plate Rushton impeller(RT-C) were studied and compared with the standard Rushton impeller(RT) operated under the same conditions.Results show that the power consumption can be decreased about 18%.Compared with the almost unchanged flow field in the lower stirred tank,the mean velocity was increased at the upper half of the stirred tank.And in the impeller region,the mean axial and radial velocities were increased,the mean tangential velocity was decreased.In addition,the average mixing time of RT-C was shortened about 4.14% than the counterpart of RT.The conclusions obtained here indicated that RT-C has a more effective mixing performance and it can be used as an alternative of RT in the process industries.
文摘Medialization has become like digitalization, rationalization, dynamization, globalization, pluralization, hybridization, and differentialization and is one of the buzzwords of modern Western industrialized societies, which are all together essentially responsible for structural change in communication. Medialization means the adaption of producers to media logics, media formats, and media routines ＆ workflows. There are consequently and logically influences because of the dynamic process of medialization to legal discourse and genres, law, media, and social power. It has to be discussed if the logics, data formats, and routines ＆ workflows of new media and information and communication technologies （ICTs） like social media are creating also a new generation of genres and novel form of legal discourses. Also, if social media will replace or complete old classic media （law of Riepl）, the question of the relevance of law concerning new ＆ social media has to be answered in close future. Lastly, if to the fore of social power, these new novel resources are actually framing for problem-based inquiries in law. There are big chances but also serious risks in cyberworld, their realities, and dangers. There actually exists an urgent call of action to theory building, development of methodologies, and empirical research.
文摘Pulsatile flow of blood in a blood vessel having time-dependent shape （diameter） is inves-tigated numerically in order to understand some important physiological phenomena in arteries. A smooth axi-symmetric cosine shaped constriction is considered. To mimic the realistic situation as far as possible, viscosity of blood is taken to be non-uniform, a shear-thinning viscosity model is considered and a physiologically relevant pulsatile flow is introduced. Taking advantage of axi-symmetry in the proposed problem, the stream function-vorticity formulation is used to solve the governing equations for blood flow. Effect of different parameters associated with the problem on the flow pattern has been investigated and disparities from the Newtonian case are discussed in detail.
