The advanced fin-shaped field-effect transistor(FinFET)technology offers higher integration density and stronger channel control capabilities,however,more complex process effects are also introduced which have signifi...The advanced fin-shaped field-effect transistor(FinFET)technology offers higher integration density and stronger channel control capabilities,however,more complex process effects are also introduced which have significant influence on device performance.To address these issues,we complete a design-technology co-optimization(DTCO)focused on FinFET,including both process-induced effect during gate formation and corresponding digital unit optimization design.The 14 nm Fin-FET complementary metal oxide semiconductor(CMOS)technology is used to illustrate the sensitivity of transistor perfor-mance to process-induced effect,specifically the poly pitch effect(PPE)and cut poly effect(CPE).Predictive technology com-puter aided design(TCAD)simulations have been carried out to evaluate the transistor performance in advance.Based on the results,optimizations in digital unit design is proposed.Fall delay of the digital unit inverter is decreased by 0.7%,and the rise delay is decreased by 2.1%.For multiple selector(MUX2NV),the delay decreases by 4.64%for rise and 3.56%for drop,respec-tively.展开更多
The photonic neural processing unit(PNPU)demonstrates ultrahigh inference speed with low energy consumption,and it has become a promising hardware artificial intelligence(AI)accelerator.However,the nonidealities of th...The photonic neural processing unit(PNPU)demonstrates ultrahigh inference speed with low energy consumption,and it has become a promising hardware artificial intelligence(AI)accelerator.However,the nonidealities of the photonic device and the peripheral circuit make the practical application much more complex.Rather than optimizing the photonic device,the architecture,and the algorithm individually,a joint device-architecture-algorithm codesign method is proposed to improve the accuracy,efficiency and robustness of the PNPU.First,a full-flow simulator for the PNPU is developed from the back end simulator to the high-level training framework;Second,the full system architecture and the complete photonic chip design enable the simulator to closely model the real system;Third,the nonidealities of the photonic chip are evaluated for the PNPU design.The average test accuracy exceeds 98%,and the computing power exceeds 100TOPS.展开更多
The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation...The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation, the thermal design of ECU for electronic unit pump （EUP） fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time展开更多
The aim of this paper is to design a water desalination plant using Reverse Osmosis membrane to treat salt water to be usable for drinkable, domestic, industrial or agricultural uses. RO unit is designed to conservati...The aim of this paper is to design a water desalination plant using Reverse Osmosis membrane to treat salt water to be usable for drinkable, domestic, industrial or agricultural uses. RO unit is designed to conservative standards for versatility in the event of feed water quality variations. The design includes a feed water flush cycle to minimize membrane fouling and piping corrosion during shutdown. The system will be all appropriate controls and instrumentation for automatic operation. All system components are available and of heavy duty industrial design and fabricated with the highest quality workmanship. Quality control will be maintained throughout all manufacturing processes. The system will produce permeate water minimum of 3600 m<sup>3</sup>/day with a quality of approximately 100 ppm total dissolved solids (TDS) when operating on well feed water with a 10,000 ppm TDS and a temperature of 25 - 30 degrees C. The design permeate recovery is 50%;and energy recovery device which saves $30,556.28/year.展开更多
This paper describes the function,structure and working status of the data buffer unitDBU,one of the most important functional units on ITM-1.It also discusses DBU’s supportto the multiprocessor system and Prolog lan...This paper describes the function,structure and working status of the data buffer unitDBU,one of the most important functional units on ITM-1.It also discusses DBU’s supportto the multiprocessor system and Prolog language.展开更多
In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for...In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for calculation of blast-induced vibration parameters like peak particle velocity （PPV） and peak particle displacement （PPD） are commonly used for estimation of blast loads in design. However, these relation- ships are not able to consider the variation in rock parameters and uncertainty of in situ conditions. In this paper, a total of 1089 published blast data of various researchers in different rock sites have been collected and used to propose generalized empirical model for PPV by considering the effects of rock parameters like unit weight, rock quality designation （ROD）, geological strength index （GSI）, and uniaxial compressive strength （UCS）. The proposed PPV model has a good correlation coefficient and hence it can be directly used in prediction of blast-induced vibrations in rocks. Standard errors and coefficient of correlations of the predicted blast-induced vibration parameters are obtained with respect to the observed field data. The proposed empirical model for PPV has also been compared with the empirical models available for blast vibrations predictions given by other researchers and found to be in good agreement with specific cases.展开更多
This paper presents a comprehensive review of recent advances in reconfigurable electromagnetic(EM)surfaces.The discussion is organized around three key aspects of reconfigurable EM surfaces:unit cell engineering desi...This paper presents a comprehensive review of recent advances in reconfigurable electromagnetic(EM)surfaces.The discussion is organized around three key aspects of reconfigurable EM surfaces:unit cell engineering design,full-wave numerical analysis,and large-scale optimization techniques.Numerous references are provided to facilitate further exploration of this compelling and timely subject.To address the above three key aspects,we conduct an extensive examination of the design process for metasurfaces in reconfigurable devices.This involves evaluating the design methodology of unit cells,EM simulation techniques tailored for highly complex structures,and innovative optimization methods suitable for scenarios with numerous variables.In scenarios featuring reconfigurability for real-time manipulation of EM waves to meet the requirements of emerging communication environments,the optimization cost function is defined with multiple variables,exhibiting intricate behavior in the design space.Consequently,it necessitates an optimization methodology capable of handling high-dimensional functions without getting trapped in local minima.Moreover,the intricate geometries of metasurface devices preclude analytical solutions,necessitating high-performance full-wave solvers capable of providing highly accurate simulations with minimal computational expense.Key concepts and details pertaining to the aforementioned design stages are presented in a unified manner,along with representative examples.展开更多
Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for au...Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, and arrowhead geometries. This paper studies the unit cell of the re-entrant hexagonal geometry to understand how changing the internal angle and fillet radius of the structure affects the Poisson’s ratio. The material chosen for this study is acrylonitrile butadiene styrene (ABS) due to its availability and frequent use in additive manufacturing. The study was based on finite element analysis. It is observed that the direction of load applied to the unit cell affects the unit cell strain, Poisson’s ratio, and maximum load capacity before failure responses. It is noticed that the re-entrant cell starts by showing a standard non-auxetic behavior until it reaches a specific axial strain value. A quadratic correlation is identified between axial and transverse strain. Designing an auxetic structure starts with understanding the behavior of a unit cell structure. The auxetic structure design is a complex process that requires a compromise between auxetic property to be achieved and load capacity via avoiding stress concentration zones.展开更多
Group reading teaching is a process in which teachers and students choose a group of articles around one or more topics, read and construct collectively, and finally achieve effective understanding. Under the backgrou...Group reading teaching is a process in which teachers and students choose a group of articles around one or more topics, read and construct collectively, and finally achieve effective understanding. Under the background of the full implementation of Chinese teaching materials, how to effectively implement Chinese literacy and make it fall firmly has opened up an innovative path through the teaching research of group text reading in and out of class under the teaching concept of "large unit design".展开更多
Impedance metasurfaces enable accurate regulation of acoustic fields.However,they can hardly supply a flexible response as such perfect operation is accompanied by stringent requirements on the design of unit cells.Ac...Impedance metasurfaces enable accurate regulation of acoustic fields.However,they can hardly supply a flexible response as such perfect operation is accompanied by stringent requirements on the design of unit cells.Actually,an arbitrary lossless and passive target impedance matrix requires the tuning of 3 independent real parameters.The set composed of a reflection phase,a transmission amplitude,and a transmission phase,enables the representation of an arbitrary impedance matrix,possibly possessing singular elements.In this paper,a mechanism of phase-amplitude-phase modulation(PAP modulation)is developed for the generic design of the unit cells of acoustic impedance metasurfaces.Adjustable acoustic impedance metasurfaces are further available under this framework.An impedance unit with 3 mobile parts is designed based on this idea.The assembled metasurface can handle different incidences for acoustic field manipulation at a given frequency.Beam steering and beam splitting are considered as demonstration examples and are verified by numerical simulation and experiment.PAP modulation enriches the design of acoustic impedance metasurfaces and extends the range of application of impedance theory.展开更多
The purpose of this study was to promote the development of large-scale agricultural machines in China and meet the demand of air seeder localization.This study investigated the relationship between the working parame...The purpose of this study was to promote the development of large-scale agricultural machines in China and meet the demand of air seeder localization.This study investigated the relationship between the working parameters and the performance of pneumatic seeding system,Cangmai 6004 wheat seed was used.A test platform for pneumatic seeding systems was developed,and then a series of experiments were performed based on the quadratic general rotary unitized design and response surface methodology(RSM).The seeding rate and the air flow rate were selected as affecting factors,coefficient of variation(CV)of evenness of feeding rate between rows and CV of seeding stability of total rows were assigned as the test indexes.Regression models between factors and indexes were established,and finally,an optimal equation based on this pneumatic seeding system were established as well,which can determine the proper air flow rate once the seeding rate was set based on the practical agronomic requirements.For example,when the seeding rate is set as 250 kg/hm^(2),the proper air flow rate of 7.53 m3/min can be obtained.The verification experiment results showed that the predicted working parameters obtained by RSM were feasible,which might provide a theoretical basis for further research of pneumatic seed metering systems.展开更多
Axial air-assisted sprayers can distribute pesticides efficiently in kiwifruit orchards.Because of improper parameter settings,most sprayers deliver either too much or too little pesticide.To identify appropriate spra...Axial air-assisted sprayers can distribute pesticides efficiently in kiwifruit orchards.Because of improper parameter settings,most sprayers deliver either too much or too little pesticide.To identify appropriate sprayer parameters for kiwifruit trees,the vertical distribution profiles of the applied liquid spray were examined in this study.The effects of spray fan speed(SFS),spray pressure(SP)and spray distance(SD)on the distributions of the sprayed liquid in the vertical profiles were studied.Combined actions of the above parameters were systematically analysed using the quadratic general rotary design test method.Regression equations for the spray liquid distributions and working factors are presented.Field confirmation experiments were carried out to optimize the parameters.Data analysis showed that the optional sprayer working parameters are those of Group 3,with an SFS equal to 1900 r/min and SP equal to 3.25 MPa.The results of this study provide a reference for future applications of this type of axial air-assisted sprayer in kiwifruit orchards.展开更多
基金supported by the National Natural Science Foundation of China (623B2028).
文摘The advanced fin-shaped field-effect transistor(FinFET)technology offers higher integration density and stronger channel control capabilities,however,more complex process effects are also introduced which have significant influence on device performance.To address these issues,we complete a design-technology co-optimization(DTCO)focused on FinFET,including both process-induced effect during gate formation and corresponding digital unit optimization design.The 14 nm Fin-FET complementary metal oxide semiconductor(CMOS)technology is used to illustrate the sensitivity of transistor perfor-mance to process-induced effect,specifically the poly pitch effect(PPE)and cut poly effect(CPE).Predictive technology com-puter aided design(TCAD)simulations have been carried out to evaluate the transistor performance in advance.Based on the results,optimizations in digital unit design is proposed.Fall delay of the digital unit inverter is decreased by 0.7%,and the rise delay is decreased by 2.1%.For multiple selector(MUX2NV),the delay decreases by 4.64%for rise and 3.56%for drop,respec-tively.
基金supported by the National Natural Science Foundation of China(Grant No.61827817)。
文摘The photonic neural processing unit(PNPU)demonstrates ultrahigh inference speed with low energy consumption,and it has become a promising hardware artificial intelligence(AI)accelerator.However,the nonidealities of the photonic device and the peripheral circuit make the practical application much more complex.Rather than optimizing the photonic device,the architecture,and the algorithm individually,a joint device-architecture-algorithm codesign method is proposed to improve the accuracy,efficiency and robustness of the PNPU.First,a full-flow simulator for the PNPU is developed from the back end simulator to the high-level training framework;Second,the full system architecture and the complete photonic chip design enable the simulator to closely model the real system;Third,the nonidealities of the photonic chip are evaluated for the PNPU design.The average test accuracy exceeds 98%,and the computing power exceeds 100TOPS.
文摘The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation, the thermal design of ECU for electronic unit pump （EUP） fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time
文摘The aim of this paper is to design a water desalination plant using Reverse Osmosis membrane to treat salt water to be usable for drinkable, domestic, industrial or agricultural uses. RO unit is designed to conservative standards for versatility in the event of feed water quality variations. The design includes a feed water flush cycle to minimize membrane fouling and piping corrosion during shutdown. The system will be all appropriate controls and instrumentation for automatic operation. All system components are available and of heavy duty industrial design and fabricated with the highest quality workmanship. Quality control will be maintained throughout all manufacturing processes. The system will produce permeate water minimum of 3600 m<sup>3</sup>/day with a quality of approximately 100 ppm total dissolved solids (TDS) when operating on well feed water with a 10,000 ppm TDS and a temperature of 25 - 30 degrees C. The design permeate recovery is 50%;and energy recovery device which saves $30,556.28/year.
基金the High Technology Research and Development Programme of china.
文摘This paper describes the function,structure and working status of the data buffer unitDBU,one of the most important functional units on ITM-1.It also discusses DBU’s supportto the multiprocessor system and Prolog language.
文摘In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for calculation of blast-induced vibration parameters like peak particle velocity （PPV） and peak particle displacement （PPD） are commonly used for estimation of blast loads in design. However, these relation- ships are not able to consider the variation in rock parameters and uncertainty of in situ conditions. In this paper, a total of 1089 published blast data of various researchers in different rock sites have been collected and used to propose generalized empirical model for PPV by considering the effects of rock parameters like unit weight, rock quality designation （ROD）, geological strength index （GSI）, and uniaxial compressive strength （UCS）. The proposed PPV model has a good correlation coefficient and hence it can be directly used in prediction of blast-induced vibrations in rocks. Standard errors and coefficient of correlations of the predicted blast-induced vibration parameters are obtained with respect to the observed field data. The proposed empirical model for PPV has also been compared with the empirical models available for blast vibrations predictions given by other researchers and found to be in good agreement with specific cases.
文摘This paper presents a comprehensive review of recent advances in reconfigurable electromagnetic(EM)surfaces.The discussion is organized around three key aspects of reconfigurable EM surfaces:unit cell engineering design,full-wave numerical analysis,and large-scale optimization techniques.Numerous references are provided to facilitate further exploration of this compelling and timely subject.To address the above three key aspects,we conduct an extensive examination of the design process for metasurfaces in reconfigurable devices.This involves evaluating the design methodology of unit cells,EM simulation techniques tailored for highly complex structures,and innovative optimization methods suitable for scenarios with numerous variables.In scenarios featuring reconfigurability for real-time manipulation of EM waves to meet the requirements of emerging communication environments,the optimization cost function is defined with multiple variables,exhibiting intricate behavior in the design space.Consequently,it necessitates an optimization methodology capable of handling high-dimensional functions without getting trapped in local minima.Moreover,the intricate geometries of metasurface devices preclude analytical solutions,necessitating high-performance full-wave solvers capable of providing highly accurate simulations with minimal computational expense.Key concepts and details pertaining to the aforementioned design stages are presented in a unified manner,along with representative examples.
文摘Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, and arrowhead geometries. This paper studies the unit cell of the re-entrant hexagonal geometry to understand how changing the internal angle and fillet radius of the structure affects the Poisson’s ratio. The material chosen for this study is acrylonitrile butadiene styrene (ABS) due to its availability and frequent use in additive manufacturing. The study was based on finite element analysis. It is observed that the direction of load applied to the unit cell affects the unit cell strain, Poisson’s ratio, and maximum load capacity before failure responses. It is noticed that the re-entrant cell starts by showing a standard non-auxetic behavior until it reaches a specific axial strain value. A quadratic correlation is identified between axial and transverse strain. Designing an auxetic structure starts with understanding the behavior of a unit cell structure. The auxetic structure design is a complex process that requires a compromise between auxetic property to be achieved and load capacity via avoiding stress concentration zones.
文摘Group reading teaching is a process in which teachers and students choose a group of articles around one or more topics, read and construct collectively, and finally achieve effective understanding. Under the background of the full implementation of Chinese teaching materials, how to effectively implement Chinese literacy and make it fall firmly has opened up an innovative path through the teaching research of group text reading in and out of class under the teaching concept of "large unit design".
基金supported by the National Natural Science Foundation of China(grant numbers 12072223,12122207,12021002,and 11991032)the EIPHI Graduate School(grant number ANR-17-EURE-0002).
文摘Impedance metasurfaces enable accurate regulation of acoustic fields.However,they can hardly supply a flexible response as such perfect operation is accompanied by stringent requirements on the design of unit cells.Actually,an arbitrary lossless and passive target impedance matrix requires the tuning of 3 independent real parameters.The set composed of a reflection phase,a transmission amplitude,and a transmission phase,enables the representation of an arbitrary impedance matrix,possibly possessing singular elements.In this paper,a mechanism of phase-amplitude-phase modulation(PAP modulation)is developed for the generic design of the unit cells of acoustic impedance metasurfaces.Adjustable acoustic impedance metasurfaces are further available under this framework.An impedance unit with 3 mobile parts is designed based on this idea.The assembled metasurface can handle different incidences for acoustic field manipulation at a given frequency.Beam steering and beam splitting are considered as demonstration examples and are verified by numerical simulation and experiment.PAP modulation enriches the design of acoustic impedance metasurfaces and extends the range of application of impedance theory.
基金the Chinese Academy of Agricultural Mechanization Sciences,State Key Laboratory of Soil Plant Machinery System Technology,and the supports of the Rural Areas National Key Technology R&D Program during the Twelfth Five-year Plan Period-Development of Farm Work Equipment Matched on Large Horsepower Tractors(2011BAD20B03).
文摘The purpose of this study was to promote the development of large-scale agricultural machines in China and meet the demand of air seeder localization.This study investigated the relationship between the working parameters and the performance of pneumatic seeding system,Cangmai 6004 wheat seed was used.A test platform for pneumatic seeding systems was developed,and then a series of experiments were performed based on the quadratic general rotary unitized design and response surface methodology(RSM).The seeding rate and the air flow rate were selected as affecting factors,coefficient of variation(CV)of evenness of feeding rate between rows and CV of seeding stability of total rows were assigned as the test indexes.Regression models between factors and indexes were established,and finally,an optimal equation based on this pneumatic seeding system were established as well,which can determine the proper air flow rate once the seeding rate was set based on the practical agronomic requirements.For example,when the seeding rate is set as 250 kg/hm^(2),the proper air flow rate of 7.53 m3/min can be obtained.The verification experiment results showed that the predicted working parameters obtained by RSM were feasible,which might provide a theoretical basis for further research of pneumatic seed metering systems.
基金The authors acknowledge that this work was financially supported by the National Key Research and Development Program(No.2016YFD0200700)the National Key R&D Program of China“the 13th Five-Year Plan”(Grant No.2016YFD0700503)the Science and Technology Project of Shaanxi Province.Also,we thank the critical comments and suggestions from the anonymous reviewers for improving the manuscript.
文摘Axial air-assisted sprayers can distribute pesticides efficiently in kiwifruit orchards.Because of improper parameter settings,most sprayers deliver either too much or too little pesticide.To identify appropriate sprayer parameters for kiwifruit trees,the vertical distribution profiles of the applied liquid spray were examined in this study.The effects of spray fan speed(SFS),spray pressure(SP)and spray distance(SD)on the distributions of the sprayed liquid in the vertical profiles were studied.Combined actions of the above parameters were systematically analysed using the quadratic general rotary design test method.Regression equations for the spray liquid distributions and working factors are presented.Field confirmation experiments were carried out to optimize the parameters.Data analysis showed that the optional sprayer working parameters are those of Group 3,with an SFS equal to 1900 r/min and SP equal to 3.25 MPa.The results of this study provide a reference for future applications of this type of axial air-assisted sprayer in kiwifruit orchards.
