This paper proposes a circuit structure which can be used for both synchronous and asynchronous pipeline control. It is a self-circulation structure with embedded delay network, and a pipeline can be controlled by thi...This paper proposes a circuit structure which can be used for both synchronous and asynchronous pipeline control. It is a self-circulation structure with embedded delay network, and a pipeline can be controlled by this structure with the interconnection of adjacent stages. This paper first proposes a basic circuit structure, then a linear pipeline is designed with self-circulation structure. The performance of linear pipeline is analyzed, and a 16-bit digital signal processor (DSP) with the structure is designed to prove the validity of the structure. Results show that about 10%-15% power consumption is saved with self-circulation structure compared with synchronous counterpart, while almost the same performance is achieved.展开更多
This paper adopts a meta-scientific method to point out that the three major obstacles hindering the formation of a unified system theory in modern science are inconsistent concepts,conflicting basic assumptions,and d...This paper adopts a meta-scientific method to point out that the three major obstacles hindering the formation of a unified system theory in modern science are inconsistent concepts,conflicting basic assumptions,and differences in the selection of mathematical languages.It focuses on the issue of“selection of basic assumptions/axioms”for in-depth research.The paper analyzes the widespread problem of logical self-circulation in core theories across multiple fields of modern science,arguing that this problem is also an important reason for theoretical stagnation and the inability to explain phenomena in depth,and may lead to consequences in practical applications.In response,the paper reflects on the limitations of revolutionary methods and proposes a generalization method as a solution.The core of this method is to inherit the reasonable parts of Newtonian mechanics,reconstruct the physical theory of complex systems based on the latest cognition,adhere to clear concepts,logical self-consistency,and unrefuted axioms,and select axioms based on the criterion of supporting the sustainable development of human society.Finally,it points out that future research can be conducted in three directions:interdisciplinary research,new perspectives in the philosophy of science,and optimization of the logical structure of theories,so as to promote the improvement and development of scientific theories.展开更多
This paper presents the design optimization of a self-circulated ventilation system for an enclosed permanent magnet(PM)traction motor utilized in the propulsion systems for subway trains.In order to analyze accuratel...This paper presents the design optimization of a self-circulated ventilation system for an enclosed permanent magnet(PM)traction motor utilized in the propulsion systems for subway trains.In order to analyze accurately the machine's inherent cooling capacity when the train is running,the ambient airflow and the related heat transfer coefficient(HTC)are numerically investigated considering synchronously the bogie installation structure.The machine is preliminary cooled with air ducts set on the motor shell,and the fluidic-thermal field distributions with only the shell air duct cooling are numerically calculated.During simulations,the HTC obtained in the former steps is applied to the external surface of the machine to model the inherent cooling characteristic caused by the train movement.To reduce the temperature rise and thus guarantee the motor's working reliability,an internal self-circulated air cooling system is proposed according to the machine temperature distribution.The air enclosed in the end-caps is driven by the blades mounted on both sides of the rotor core and forms two air circuits to bring the excessive power losses generated in the heating components to cool regions.The fluid flow and temperature rise distributions of the cooling system's structural parameters are further improved by the Taguchi method in order to confirm the efficacy of the internal air cooling system.展开更多
To optimize the structure of the burner,improve the combustion performance,and reduce the emission of NO_(x),a self-circulating low NO_(x)combustion technology was used to design a new type of flue gas self-circulatin...To optimize the structure of the burner,improve the combustion performance,and reduce the emission of NO_(x),a self-circulating low NO_(x)combustion technology was used to design a new type of flue gas self-circulating low NO_(x)burner.Based on previous research on the numerical model of combustion and the composition of mixed gas on combustion and NO_(x)emissions,the effect of various factors on the ejection coefficient of the flue gas self-circulating structure was analyzed using the orthogonal test method,and the burner operating parameters,such as preheating temperature and excess air coefficient,were deeply studied through the three-dimensional finite element numerical model in this paper.The results show that the diameter ratio of the nozzle and the length of the cylindrical section of the flue gas self-circulating structure have great influence on its ejection and mixing ability.The optimal ejection coefficient was 0.4829.Overall,the amount of NO_(x)emissions greatly increased from 6.23×10^(-6)(volume fraction)at the preheating temperature 973 K to 3.5×10^(-3)at preheating temperature 1573 K.When the excess air coefficient decreased from 1.2 to 1,the maximum combustion temperature decreased from 2036.3 K to 1954.22 K,and the NO_(x)emissions decreased from 352.29×10^(-6)to 159.73×10^(-6).展开更多
基金Sponsored by the National High Technology Research and Development Program of China(Grant No.2003AA1Z1350)
文摘This paper proposes a circuit structure which can be used for both synchronous and asynchronous pipeline control. It is a self-circulation structure with embedded delay network, and a pipeline can be controlled by this structure with the interconnection of adjacent stages. This paper first proposes a basic circuit structure, then a linear pipeline is designed with self-circulation structure. The performance of linear pipeline is analyzed, and a 16-bit digital signal processor (DSP) with the structure is designed to prove the validity of the structure. Results show that about 10%-15% power consumption is saved with self-circulation structure compared with synchronous counterpart, while almost the same performance is achieved.
基金supported by the start-up funding from Westlake University under Grant Number 041030150118.
文摘This paper adopts a meta-scientific method to point out that the three major obstacles hindering the formation of a unified system theory in modern science are inconsistent concepts,conflicting basic assumptions,and differences in the selection of mathematical languages.It focuses on the issue of“selection of basic assumptions/axioms”for in-depth research.The paper analyzes the widespread problem of logical self-circulation in core theories across multiple fields of modern science,arguing that this problem is also an important reason for theoretical stagnation and the inability to explain phenomena in depth,and may lead to consequences in practical applications.In response,the paper reflects on the limitations of revolutionary methods and proposes a generalization method as a solution.The core of this method is to inherit the reasonable parts of Newtonian mechanics,reconstruct the physical theory of complex systems based on the latest cognition,adhere to clear concepts,logical self-consistency,and unrefuted axioms,and select axioms based on the criterion of supporting the sustainable development of human society.Finally,it points out that future research can be conducted in three directions:interdisciplinary research,new perspectives in the philosophy of science,and optimization of the logical structure of theories,so as to promote the improvement and development of scientific theories.
基金supported by the National Natural Science Foundation of China under Grant 52107007the China Scholarship Council under Grant 202008120084the“Chunhui Plan”Collaborative Research Project of Chinese Ministry of Education under Grant HZKY20220604。
文摘This paper presents the design optimization of a self-circulated ventilation system for an enclosed permanent magnet(PM)traction motor utilized in the propulsion systems for subway trains.In order to analyze accurately the machine's inherent cooling capacity when the train is running,the ambient airflow and the related heat transfer coefficient(HTC)are numerically investigated considering synchronously the bogie installation structure.The machine is preliminary cooled with air ducts set on the motor shell,and the fluidic-thermal field distributions with only the shell air duct cooling are numerically calculated.During simulations,the HTC obtained in the former steps is applied to the external surface of the machine to model the inherent cooling characteristic caused by the train movement.To reduce the temperature rise and thus guarantee the motor's working reliability,an internal self-circulated air cooling system is proposed according to the machine temperature distribution.The air enclosed in the end-caps is driven by the blades mounted on both sides of the rotor core and forms two air circuits to bring the excessive power losses generated in the heating components to cool regions.The fluid flow and temperature rise distributions of the cooling system's structural parameters are further improved by the Taguchi method in order to confirm the efficacy of the internal air cooling system.
基金supported by the Fundamental Research Funds for the Central Universities of China(FRF-TP-18-074A1,FRF-BD-20-09A)the China Postdoctoral Science Foundation(No.2019M650491)the National Natural Science Foundation of China(No.11801029)。
文摘To optimize the structure of the burner,improve the combustion performance,and reduce the emission of NO_(x),a self-circulating low NO_(x)combustion technology was used to design a new type of flue gas self-circulating low NO_(x)burner.Based on previous research on the numerical model of combustion and the composition of mixed gas on combustion and NO_(x)emissions,the effect of various factors on the ejection coefficient of the flue gas self-circulating structure was analyzed using the orthogonal test method,and the burner operating parameters,such as preheating temperature and excess air coefficient,were deeply studied through the three-dimensional finite element numerical model in this paper.The results show that the diameter ratio of the nozzle and the length of the cylindrical section of the flue gas self-circulating structure have great influence on its ejection and mixing ability.The optimal ejection coefficient was 0.4829.Overall,the amount of NO_(x)emissions greatly increased from 6.23×10^(-6)(volume fraction)at the preheating temperature 973 K to 3.5×10^(-3)at preheating temperature 1573 K.When the excess air coefficient decreased from 1.2 to 1,the maximum combustion temperature decreased from 2036.3 K to 1954.22 K,and the NO_(x)emissions decreased from 352.29×10^(-6)to 159.73×10^(-6).
