For achieving personalized speech synthesis,it is indispensable to synthesize speech with diverse prosody for any given text.This task presents two key challenges:first,existing methods struggle to simultaneously extr...For achieving personalized speech synthesis,it is indispensable to synthesize speech with diverse prosody for any given text.This task presents two key challenges:first,existing methods struggle to simultaneously extract local prosody information and control phoneme duration,while overlooking the impact of duration on prosody;second,current speaker adaptation approaches suffer from slow learning speed or poor generalization to unseen speakers outside the training set.To address the aforementioned issues,this paper introduces a novel framework.Our method innovatively introduces the text-to-speech alignment mechanism into prosody modeling,using the aligned text-to-duration to segment speech and obtain local prosodic information,and simultaneously training the two components simplifies the workflow.After obtaining the prosodic information,we use it as a condition to guide the model to learn the corresponding phoneme durations under different types of prosody.We combine this style control work with adapter fine-tuning to quickly synthesize speech with the speaker’s style using small amounts of data from unseen speakers in the training set.Experimental results show that our approach is effective in adjusting prosody and variable duration as well as fast style adapter,and the subjective evaluations of the prosodic modulation model considering duration exhibits a significant improvement.展开更多
The electricity-hydrogen integrated energy system(EH-IES)enables synergistic operation of electricity,heat,and hydrogen subsystems,supporting renewable energy integration and efficient multi-energy utilization in futu...The electricity-hydrogen integrated energy system(EH-IES)enables synergistic operation of electricity,heat,and hydrogen subsystems,supporting renewable energy integration and efficient multi-energy utilization in future low carbon societies.However,uncertainties from renewable energy and load variability threaten system safety and economy.Conventional chance-constrained programming(CCP)ensures reliable operation by limiting risk.However,increasing source-load uncertainties that can render CCP models infeasible and exacerbate operational risks.To address this,this paper proposes a risk-adjustable chance-constrained goal programming(RACCGP)model,integrating CCP and goal programming to balance risk and cost based on system risk assessment.An intelligent nonlinear goal programming method based on the state transition algorithm(STA)is developed,along with an improved discretized step transformation,to handle model nonlinearity and enhance computational efficiency.Experimental results show that the proposed model reduces costs while controlling risk compared to traditional CCP,and the solution method outperforms average sample sampling in efficiency and solution quality.展开更多
The increasingly complex battlefield environment requests much closer connection in a team having both manned and unmanned aerial vehicles(MAVs and UAVs). This special heterogeneous team structure causes demands for e...The increasingly complex battlefield environment requests much closer connection in a team having both manned and unmanned aerial vehicles(MAVs and UAVs). This special heterogeneous team structure causes demands for effective organizational structure design solutions. Implementing adjustable autonomy in the organizational structure, the expected evaluation function is established based on the physical resource, intelligent resource, network efficiency, network vulnerability and task execution reliability. According to the above constraints, together with interaction latency, decision-making information processing capacity, and decision-making latency, we aim to find a preferential organizational structure. The proposed organizational structure includes cooperative relationships, supervisory control relationships, and decision-making authorization relationships. In addition,by considering the influence on the intelligent support capabilities and the task execution reliability created by adjustable autonomy, it helps to build the proposed organizational structure designed with certain degree of flexibility to deal with the potential changes in the unpredictable battlefield environment. Simulation is conducted to confirm our design to be valid. And the method is still valid under different battlefield environments and interventions.展开更多
Based on KKT complementary condition in optimization theory, an unconstrained non-differential optimization model for support vector machine is proposed. An adjustable entropy function method is given to deal with the...Based on KKT complementary condition in optimization theory, an unconstrained non-differential optimization model for support vector machine is proposed. An adjustable entropy function method is given to deal with the proposed optimization problem and the Newton algorithm is used to figure out the optimal solution. The proposed method can find an optimal solution with a relatively small parameter p, which avoids the numerical overflow in the traditional entropy function methods. It is a new approach to solve support vector machine. The theoretical analysis and experimental results illustrate the feasibility and efficiency of the proposed algorithm.展开更多
A new kind of optimal fuzzy PID controller is proposed, which contains two parts. One is an on line fuzzy inference system, and the other is a conventional PID controller. In the fuzzy inference system, three adjustab...A new kind of optimal fuzzy PID controller is proposed, which contains two parts. One is an on line fuzzy inference system, and the other is a conventional PID controller. In the fuzzy inference system, three adjustable factors x p, x i , and x d are introduced. Their functions are to further modify and optimize the result of the fuzzy inference so as to make the controller have the optimal control effect on a given object. The optimal values of these adjustable factors are determined based on the ITAE criterion and the Nelder and Mead′s flexible polyhedron search algorithm. This optimal fuzzy PID controller has been used to control the executive motor of the intelligent artificial leg designed by the authors. The result of computer simulation indicates that this controller is very effective and can be widely used to control different kinds of objects and processes.展开更多
A hierarchical scheme of feature-based model similarity measurement was proposed,named CSG_D2,in which both geometry similarity and topology similarity were applied.The features of 3D mechanical part were constructed ...A hierarchical scheme of feature-based model similarity measurement was proposed,named CSG_D2,in which both geometry similarity and topology similarity were applied.The features of 3D mechanical part were constructed by a series of primitive features with tree structure,as a form of constructive solid geometry(CSG) tree.The D2 shape distributions of these features were extracted for geometry similarity measurement,and the pose vector and non-disappeared proportion of each leaf node were gained for topology similarity measurement.Based on these,the dissimilarity between the query and the candidate was accessed by level-by-level CSG tree comparisons.With the adjustable weights,our scheme satisfies different comparison emphasis on the geometry or topology similarity.The assessment results from CSG_D2 demonstrate more discriminative than those from D2 in the analysis of precision-recall and similarity matrix.Finally,an experimental search engine is applied for mechanical parts reuse by using CSG_D2,which is convenient for the mechanical design process.展开更多
In this paper,a bandwidth-adjustable extended state observer(ABESO)is proposed for the systems with measurement noise.It is known that increasing the bandwidth of the observer improves the tracking speed but tolerates...In this paper,a bandwidth-adjustable extended state observer(ABESO)is proposed for the systems with measurement noise.It is known that increasing the bandwidth of the observer improves the tracking speed but tolerates noise,which conflicts with observation accuracy.Therefore,we introduce a bandwidth scaling factor such that ABESO is formulated to a 2-degree-of-freedom system.The observer gain is determined and the bandwidth scaling factor adjusts the bandwidth according to the tracking error.When the tracking error decreases,the bandwidth decreases to suppress the noise,otherwise the bandwidth does not change.It is proven that the error dynamics are bounded and converge in finite time.The relationship between the upper bound of the estimation error and the scaling factor is given.When the scaling factor is less than 1,the ABESO has higher estimation accuracy than the linear extended state observer(LESO).Simulations of an uncertain nonlinear system with compound disturbances show that the proposed ABESO can successfully estimate the total disturbance in noisy environments.The mean error of total disturbance of ABESO is 15.28% lower than that of LESO.展开更多
To simulate the different lunar phases and ensure continuous adjustability of the radiant brightness,a new broad spectrum light and frosted glass were applied and designed in the optical system for lunar simulator wit...To simulate the different lunar phases and ensure continuous adjustability of the radiant brightness,a new broad spectrum light and frosted glass were applied and designed in the optical system for lunar simulator with the shapes and radiance being able to be adjusted.According to the engineering demand and index requirements of the optical system,three major design aspects are addressed,including the high reliability and maintainability for broad-spectrum light,heat dissipation in lunar simulator for long working hours,and bearing of the main frame under different working conditions.By designing a reasonable machine structure,and through the structure itself with the matrix arrangement of 48 axial flow fans,an effectively cooling air duct is established.Deformation and temperature were calculated by the finite element software ANSYS.The results showed that the displacement deformation reached 0.33 mm and stress deformation reached 0.02 MPa at the temperature of 20℃;when the main frame was in the temperature field between 20℃ and65℃,the maximum displacement deformation reached 13.30 mm and maximum stress deformation is 97.90 MPa,and the amount of this deformation is very small in considering of the mechanical structure dimensions and weight of the lunar simulator.展开更多
To solve the inequality problem, an adjustable entropy method is proposed. An inequality problem can be transformed into a minimax problem which is nondifferentiable; then an adjustable entropy is used to smooth the m...To solve the inequality problem, an adjustable entropy method is proposed. An inequality problem can be transformed into a minimax problem which is nondifferentiable; then an adjustable entropy is used to smooth the minimax problem. The solution of inequalities can be approached by using a BFGS algorithm of the standard optimization method. Some properties of the new approximate function are presented and then the global convergence are given according to the algorithm. Two numerical examples illustrate that the proposed method is efficient and is superior to the former ones.展开更多
A light source of multi-star simulator capable of background adjustment and magnitude control has been designed.Two integrating spheres are employed as the star-point light source and the background light source respe...A light source of multi-star simulator capable of background adjustment and magnitude control has been designed.Two integrating spheres are employed as the star-point light source and the background light source respectively.A beam splitter prism has been designed to serve as the beam combiner for the star-point and the background light sources,and a mathematical model has been constructed respectively to compute the light flux of the two integrating spheres.A magnitude testing system and a background testing system have been created using low-light illuminometer,luminance meter,and testing instruments to measure the star-point magnitude and the background luminance of the multi-star simulator.The test results suggest that the star-point magnitude is adjustable from0 to+5 m_v,with a simulation precision superior to ±0.026 m_v.The maximum background luminance is 3.8×10~5 cd·m^(-2),and the minimum background luminance is6.4×10^(-2)cd·m^(-2).The designed light source system can meet the requirements for simulating the stellar map with a sky background.展开更多
Powder engine as a novel type of engine using high-energy metal powder as fuel and gas,liquid,or solid as oxidizer.These engines exhibit remarkable adaptability,flexible thrust regulation,and multi-pulse start-stop,wh...Powder engine as a novel type of engine using high-energy metal powder as fuel and gas,liquid,or solid as oxidizer.These engines exhibit remarkable adaptability,flexible thrust regulation,and multi-pulse start-stop,which have significant application potentials in the fields of near-Earth space development,space propulsion systems,and deep-sea exploration.The scope of this review encompasses the classification and application of powder engines,the classification of powdered fuel supply systems,and the prospective trajectories and pivotal challenges of powder engines and fuel supply technologies.This work points out that although certain ground-based experimental challenges on powder engines have been solved,the relative technology remains in the nascent stages of feasibility demonstration and testing.The pneumatic and motor-driven piston methods currently dominate as the primary means for supplying fuel,and the structure of the piston and intake should be further optimized in the future to promote fuel fluidization and delivery efficiency.The adaptability of powder engines and powdered fuels under different pre-treatment and loading methods should be evaluated.Furthermore,the stability of powdered fuel delivery across varying operational environments,the accuracy of CFD modeling,and the precision of mass flow rate measurement and prediction technologies necessitate further enhancement and refinement.These advancements are crucial for the maturation of powder engine technology and its integration into practical applications.展开更多
Economic growth is often accompanied by escalating ecological challenges,making cross-regional collaborative environmental governance a key policy approach.However,practical constraints,such as insufficient governance...Economic growth is often accompanied by escalating ecological challenges,making cross-regional collaborative environmental governance a key policy approach.However,practical constraints,such as insufficient governance capacity,high costs,and a lack of accountability mechanisms,hinder regional cooperation in ecological protection.In response,new ecological compensation agreements have emerged.This study examines the effectiveness of the bidirectional compensation strategy and the impacts of various factors on upstream and downstream decision-making,with upstream–downstream cooperation under China’s newly implemented cross-regional ecological compensation agreements as the entry point.Using evolutionary game theory,a cross-regional collaborative governance model is developed,and numerical simulations are conducted to explore the interaction mechanisms between participants and the factors influencing stable strategies.The findings indicate that,first,strategy stability is primarily associated with upstream regions,with compensation amounts,central government incentives,upstream protection costs,and comprehensive benefits exerting varying degrees of influence on the watershed ecological compensation mechanism.Notably,the downstream region exhibits greater sensitivity to compensation amounts than the upstream region,while forgone opportunity costs and comprehensive ecological benefits are critical drivers of upstream environmental governance.Second,the analysis of the central government’s regulatory mechanism within the tripartite evolutionary game underscores the importance of a centrally led governance model in ensuring the long-term ecological integrity of the watershed and promoting fair interregional cooperation.Third,future policy-making should incorporate regional interests to establish more flexible and scientifically grounded ecological compensation mechanisms,fostering coordinated cross-regional governance and achieving a balance between ecological protection and economic growth.展开更多
To realize effective co-phasing adjustment in large-aperture sparse-aperture telescopes,a multichannel stripe tracking approach is employed,allowing simultaneous interferometric measurements of multiple optical paths ...To realize effective co-phasing adjustment in large-aperture sparse-aperture telescopes,a multichannel stripe tracking approach is employed,allowing simultaneous interferometric measurements of multiple optical paths and circumventing the need for pairwise measurements along the mirror boundaries in traditional interferometric methods.This approach enhances detection efficiency and reduces system complexity.Here,the principles of the multibeam interference process and construction of a co-phasing detection module based on direct optical fiber connections were analyzed using wavefront optics theory.Error analysis was conducted on the system surface obtained through multipath interference.Potential applications of the interferometric method were explored.Finally,the principle was verified by experiment,an interferometric fringe contrast better than 0.4 is achieved through flat field calibration and incoherent digital synthesis.The dynamic range of the measurement exceeds 10 times of the center wavelength of the working band(1550 nm).Moreover,a resolution better than one-tenth of the working center wavelength(1550 nm)was achieved.Simultaneous three-beam interference can be achieved,leading to a 50%improvement in detection efficiency.This method can effectively enhance the efficiency of sparse aperture telescope co-phasing,meeting the requirements for observations of 8-10 m telescopes.This study provides a technological foundation for observing distant and faint celestial objects.展开更多
In order to study the preferred skin color for printing images,two CMYK images from ISO 400 and one from iStock,including five skin color images of East Asian females was selected in this study.The images were adjuste...In order to study the preferred skin color for printing images,two CMYK images from ISO 400 and one from iStock,including five skin color images of East Asian females was selected in this study.The images were adjusted with the CMYK printing ink volume variation of the single,double and triple channels in the given 280%total ink limit conditions.A larger number of color vision normal observers were organized to carry out the color preference evaluation experiment,and the selected preferred skin colors were analyzed.The distribution range of the chromaticity values for skin color images were obtained and the results indicated that there are three regions for printing skin color preferences,and the observers have a memory preference for brighter,fairer skin colors in young female and a reddish skin colors in girl,which can provide the guidance for color adjustment of printed skin color images.展开更多
To meet increasingly stringent emission standards and lower the brake-specific fuel consumption(BSFC)of marine engines,a collaborative optimization study of exhaust gas recirculation(EGR)and a Miller cycle coupled tur...To meet increasingly stringent emission standards and lower the brake-specific fuel consumption(BSFC)of marine engines,a collaborative optimization study of exhaust gas recirculation(EGR)and a Miller cycle coupled turbocharging system was carried out.In this study,a one-dimensional numerical model of the EGR,Miller cycle,and adjustable two-stage turbocharged engine based on WeiChai 6170 marine diesel engine was established.The particle swarm optimization algorithm was used to achieve multi-input and multi-objective comprehensive optimization,and the effects of EGR-coupled Miller regulation and high-pressure turbine bypass regulation on NO_(x)and BSFC were investigated.The results showed that a medium EGR rate-coupled medium Miller degree was better for the comprehensive optimization of NO_(x)and BSFC.At medium EGR rate and low turbine bypass rates,NO_(x)and BSFC were relatively balanced and acceptable.Finally,an optimal steady-state control strategy under full loads was proposed.With an increase in loads,the optimized turbine bypass rate and Miller degree gradually increased.Compared with the EGRonly system,the optimal system of EGR and Miller cycle coupled turbine bypass reduced NO_(x)by 0.87 g/(kW·h)and BSFC by 17.19 g/(kW·h)at 100%load.Therefore,the EGR and Miller cycle coupled adjustable two-stage turbocharging achieves NO_(x)and BSFC optimization under full loads.展开更多
A new faster block-matching algorithm （BMA） by using both search candidate and pixd sulzsamplings is proposed. Firstly a pixd-subsampling approach used in adjustable partial distortion search （APDS） is adjusted to...A new faster block-matching algorithm （BMA） by using both search candidate and pixd sulzsamplings is proposed. Firstly a pixd-subsampling approach used in adjustable partial distortion search （APDS） is adjusted to visit about half points of all search candidates by subsampling them, using a spiral-scanning path with one skip. Two sdected candidates that have minimal and second minimal block distortion measures are obtained. Then a fine-tune step is taken around them to find the best one. Some analyses are given to approve the rationality of the approach of this paper. Experimental results show that, as compared to APDS, the proposed algorithm can enhance the block-matching speed by about 30% while maintaining its MSE performance very close to that of it. And it performs much better than many other BMAs such as TSS, NTSS, UCDBS and NPDS.展开更多
基金supported by the National Nature Science Foundation of China(U23B2028,62232006,62032006,62102127)the Fundamental Research Funds for the Central Universities(WK2100000047,WK2100000026).
文摘For achieving personalized speech synthesis,it is indispensable to synthesize speech with diverse prosody for any given text.This task presents two key challenges:first,existing methods struggle to simultaneously extract local prosody information and control phoneme duration,while overlooking the impact of duration on prosody;second,current speaker adaptation approaches suffer from slow learning speed or poor generalization to unseen speakers outside the training set.To address the aforementioned issues,this paper introduces a novel framework.Our method innovatively introduces the text-to-speech alignment mechanism into prosody modeling,using the aligned text-to-duration to segment speech and obtain local prosodic information,and simultaneously training the two components simplifies the workflow.After obtaining the prosodic information,we use it as a condition to guide the model to learn the corresponding phoneme durations under different types of prosody.We combine this style control work with adapter fine-tuning to quickly synthesize speech with the speaker’s style using small amounts of data from unseen speakers in the training set.Experimental results show that our approach is effective in adjusting prosody and variable duration as well as fast style adapter,and the subjective evaluations of the prosodic modulation model considering duration exhibits a significant improvement.
基金Project(2022YFC2904502)supported by the National Key Research and Development Program of ChinaProject(62273357)supported by the National Natural Science Foundation of China。
文摘The electricity-hydrogen integrated energy system(EH-IES)enables synergistic operation of electricity,heat,and hydrogen subsystems,supporting renewable energy integration and efficient multi-energy utilization in future low carbon societies.However,uncertainties from renewable energy and load variability threaten system safety and economy.Conventional chance-constrained programming(CCP)ensures reliable operation by limiting risk.However,increasing source-load uncertainties that can render CCP models infeasible and exacerbate operational risks.To address this,this paper proposes a risk-adjustable chance-constrained goal programming(RACCGP)model,integrating CCP and goal programming to balance risk and cost based on system risk assessment.An intelligent nonlinear goal programming method based on the state transition algorithm(STA)is developed,along with an improved discretized step transformation,to handle model nonlinearity and enhance computational efficiency.Experimental results show that the proposed model reduces costs while controlling risk compared to traditional CCP,and the solution method outperforms average sample sampling in efficiency and solution quality.
基金supported by the National Natural Science Foundation of China(61305133)the Aeronautical Science Foundation of China(2016ZC53020)the Fundamental Research Funds for the Central Universities(3102017jg02015)
文摘The increasingly complex battlefield environment requests much closer connection in a team having both manned and unmanned aerial vehicles(MAVs and UAVs). This special heterogeneous team structure causes demands for effective organizational structure design solutions. Implementing adjustable autonomy in the organizational structure, the expected evaluation function is established based on the physical resource, intelligent resource, network efficiency, network vulnerability and task execution reliability. According to the above constraints, together with interaction latency, decision-making information processing capacity, and decision-making latency, we aim to find a preferential organizational structure. The proposed organizational structure includes cooperative relationships, supervisory control relationships, and decision-making authorization relationships. In addition,by considering the influence on the intelligent support capabilities and the task execution reliability created by adjustable autonomy, it helps to build the proposed organizational structure designed with certain degree of flexibility to deal with the potential changes in the unpredictable battlefield environment. Simulation is conducted to confirm our design to be valid. And the method is still valid under different battlefield environments and interventions.
基金the National Natural Science Foundation of China (60574075)
文摘Based on KKT complementary condition in optimization theory, an unconstrained non-differential optimization model for support vector machine is proposed. An adjustable entropy function method is given to deal with the proposed optimization problem and the Newton algorithm is used to figure out the optimal solution. The proposed method can find an optimal solution with a relatively small parameter p, which avoids the numerical overflow in the traditional entropy function methods. It is a new approach to solve support vector machine. The theoretical analysis and experimental results illustrate the feasibility and efficiency of the proposed algorithm.
文摘A new kind of optimal fuzzy PID controller is proposed, which contains two parts. One is an on line fuzzy inference system, and the other is a conventional PID controller. In the fuzzy inference system, three adjustable factors x p, x i , and x d are introduced. Their functions are to further modify and optimize the result of the fuzzy inference so as to make the controller have the optimal control effect on a given object. The optimal values of these adjustable factors are determined based on the ITAE criterion and the Nelder and Mead′s flexible polyhedron search algorithm. This optimal fuzzy PID controller has been used to control the executive motor of the intelligent artificial leg designed by the authors. The result of computer simulation indicates that this controller is very effective and can be widely used to control different kinds of objects and processes.
基金Project(51175287)supported by the National Natural Science Foundation of ChinaProject(2006AA04Z112)supported by National High Technology Research and Development Program of China
文摘A hierarchical scheme of feature-based model similarity measurement was proposed,named CSG_D2,in which both geometry similarity and topology similarity were applied.The features of 3D mechanical part were constructed by a series of primitive features with tree structure,as a form of constructive solid geometry(CSG) tree.The D2 shape distributions of these features were extracted for geometry similarity measurement,and the pose vector and non-disappeared proportion of each leaf node were gained for topology similarity measurement.Based on these,the dissimilarity between the query and the candidate was accessed by level-by-level CSG tree comparisons.With the adjustable weights,our scheme satisfies different comparison emphasis on the geometry or topology similarity.The assessment results from CSG_D2 demonstrate more discriminative than those from D2 in the analysis of precision-recall and similarity matrix.Finally,an experimental search engine is applied for mechanical parts reuse by using CSG_D2,which is convenient for the mechanical design process.
基金supported by the National Natural Science Foundation of China(61873126)。
文摘In this paper,a bandwidth-adjustable extended state observer(ABESO)is proposed for the systems with measurement noise.It is known that increasing the bandwidth of the observer improves the tracking speed but tolerates noise,which conflicts with observation accuracy.Therefore,we introduce a bandwidth scaling factor such that ABESO is formulated to a 2-degree-of-freedom system.The observer gain is determined and the bandwidth scaling factor adjusts the bandwidth according to the tracking error.When the tracking error decreases,the bandwidth decreases to suppress the noise,otherwise the bandwidth does not change.It is proven that the error dynamics are bounded and converge in finite time.The relationship between the upper bound of the estimation error and the scaling factor is given.When the scaling factor is less than 1,the ABESO has higher estimation accuracy than the linear extended state observer(LESO).Simulations of an uncertain nonlinear system with compound disturbances show that the proposed ABESO can successfully estimate the total disturbance in noisy environments.The mean error of total disturbance of ABESO is 15.28% lower than that of LESO.
基金Supported by National Public Welfare Industry(GYHY200706003,GYHY201006043)
文摘To simulate the different lunar phases and ensure continuous adjustability of the radiant brightness,a new broad spectrum light and frosted glass were applied and designed in the optical system for lunar simulator with the shapes and radiance being able to be adjusted.According to the engineering demand and index requirements of the optical system,three major design aspects are addressed,including the high reliability and maintainability for broad-spectrum light,heat dissipation in lunar simulator for long working hours,and bearing of the main frame under different working conditions.By designing a reasonable machine structure,and through the structure itself with the matrix arrangement of 48 axial flow fans,an effectively cooling air duct is established.Deformation and temperature were calculated by the finite element software ANSYS.The results showed that the displacement deformation reached 0.33 mm and stress deformation reached 0.02 MPa at the temperature of 20℃;when the main frame was in the temperature field between 20℃ and65℃,the maximum displacement deformation reached 13.30 mm and maximum stress deformation is 97.90 MPa,and the amount of this deformation is very small in considering of the mechanical structure dimensions and weight of the lunar simulator.
文摘To solve the inequality problem, an adjustable entropy method is proposed. An inequality problem can be transformed into a minimax problem which is nondifferentiable; then an adjustable entropy is used to smooth the minimax problem. The solution of inequalities can be approached by using a BFGS algorithm of the standard optimization method. Some properties of the new approximate function are presented and then the global convergence are given according to the algorithm. Two numerical examples illustrate that the proposed method is efficient and is superior to the former ones.
基金Supported by Jilin Province Key Scientific and Technological Projects(20160204008GX)National Key Laboratory Fund Project(61420020210162002)Changchun University of Science and Technology Innovation Fund(XJJLG-2016-15)
文摘A light source of multi-star simulator capable of background adjustment and magnitude control has been designed.Two integrating spheres are employed as the star-point light source and the background light source respectively.A beam splitter prism has been designed to serve as the beam combiner for the star-point and the background light sources,and a mathematical model has been constructed respectively to compute the light flux of the two integrating spheres.A magnitude testing system and a background testing system have been created using low-light illuminometer,luminance meter,and testing instruments to measure the star-point magnitude and the background luminance of the multi-star simulator.The test results suggest that the star-point magnitude is adjustable from0 to+5 m_v,with a simulation precision superior to ±0.026 m_v.The maximum background luminance is 3.8×10~5 cd·m^(-2),and the minimum background luminance is6.4×10^(-2)cd·m^(-2).The designed light source system can meet the requirements for simulating the stellar map with a sky background.
基金supported by the National Natural Science Foundation of China(grant number:12102161)the Key Research and Development Program of Jiangxi Province,China(grant number:20232BBE50005)the Natural Science Foundation of Jiangxi Province,China(grant number:20224BAB214060)。
文摘Powder engine as a novel type of engine using high-energy metal powder as fuel and gas,liquid,or solid as oxidizer.These engines exhibit remarkable adaptability,flexible thrust regulation,and multi-pulse start-stop,which have significant application potentials in the fields of near-Earth space development,space propulsion systems,and deep-sea exploration.The scope of this review encompasses the classification and application of powder engines,the classification of powdered fuel supply systems,and the prospective trajectories and pivotal challenges of powder engines and fuel supply technologies.This work points out that although certain ground-based experimental challenges on powder engines have been solved,the relative technology remains in the nascent stages of feasibility demonstration and testing.The pneumatic and motor-driven piston methods currently dominate as the primary means for supplying fuel,and the structure of the piston and intake should be further optimized in the future to promote fuel fluidization and delivery efficiency.The adaptability of powder engines and powdered fuels under different pre-treatment and loading methods should be evaluated.Furthermore,the stability of powdered fuel delivery across varying operational environments,the accuracy of CFD modeling,and the precision of mass flow rate measurement and prediction technologies necessitate further enhancement and refinement.These advancements are crucial for the maturation of powder engine technology and its integration into practical applications.
基金supported by the National Natural Science Foundation of China(72071192,72188101)。
文摘Economic growth is often accompanied by escalating ecological challenges,making cross-regional collaborative environmental governance a key policy approach.However,practical constraints,such as insufficient governance capacity,high costs,and a lack of accountability mechanisms,hinder regional cooperation in ecological protection.In response,new ecological compensation agreements have emerged.This study examines the effectiveness of the bidirectional compensation strategy and the impacts of various factors on upstream and downstream decision-making,with upstream–downstream cooperation under China’s newly implemented cross-regional ecological compensation agreements as the entry point.Using evolutionary game theory,a cross-regional collaborative governance model is developed,and numerical simulations are conducted to explore the interaction mechanisms between participants and the factors influencing stable strategies.The findings indicate that,first,strategy stability is primarily associated with upstream regions,with compensation amounts,central government incentives,upstream protection costs,and comprehensive benefits exerting varying degrees of influence on the watershed ecological compensation mechanism.Notably,the downstream region exhibits greater sensitivity to compensation amounts than the upstream region,while forgone opportunity costs and comprehensive ecological benefits are critical drivers of upstream environmental governance.Second,the analysis of the central government’s regulatory mechanism within the tripartite evolutionary game underscores the importance of a centrally led governance model in ensuring the long-term ecological integrity of the watershed and promoting fair interregional cooperation.Third,future policy-making should incorporate regional interests to establish more flexible and scientifically grounded ecological compensation mechanisms,fostering coordinated cross-regional governance and achieving a balance between ecological protection and economic growth.
文摘To realize effective co-phasing adjustment in large-aperture sparse-aperture telescopes,a multichannel stripe tracking approach is employed,allowing simultaneous interferometric measurements of multiple optical paths and circumventing the need for pairwise measurements along the mirror boundaries in traditional interferometric methods.This approach enhances detection efficiency and reduces system complexity.Here,the principles of the multibeam interference process and construction of a co-phasing detection module based on direct optical fiber connections were analyzed using wavefront optics theory.Error analysis was conducted on the system surface obtained through multipath interference.Potential applications of the interferometric method were explored.Finally,the principle was verified by experiment,an interferometric fringe contrast better than 0.4 is achieved through flat field calibration and incoherent digital synthesis.The dynamic range of the measurement exceeds 10 times of the center wavelength of the working band(1550 nm).Moreover,a resolution better than one-tenth of the working center wavelength(1550 nm)was achieved.Simultaneous three-beam interference can be achieved,leading to a 50%improvement in detection efficiency.This method can effectively enhance the efficiency of sparse aperture telescope co-phasing,meeting the requirements for observations of 8-10 m telescopes.This study provides a technological foundation for observing distant and faint celestial objects.
文摘In order to study the preferred skin color for printing images,two CMYK images from ISO 400 and one from iStock,including five skin color images of East Asian females was selected in this study.The images were adjusted with the CMYK printing ink volume variation of the single,double and triple channels in the given 280%total ink limit conditions.A larger number of color vision normal observers were organized to carry out the color preference evaluation experiment,and the selected preferred skin colors were analyzed.The distribution range of the chromaticity values for skin color images were obtained and the results indicated that there are three regions for printing skin color preferences,and the observers have a memory preference for brighter,fairer skin colors in young female and a reddish skin colors in girl,which can provide the guidance for color adjustment of printed skin color images.
基金Project(K16011)supported by the Marine Low-speed Engine Project-Phase I,China。
文摘To meet increasingly stringent emission standards and lower the brake-specific fuel consumption(BSFC)of marine engines,a collaborative optimization study of exhaust gas recirculation(EGR)and a Miller cycle coupled turbocharging system was carried out.In this study,a one-dimensional numerical model of the EGR,Miller cycle,and adjustable two-stage turbocharged engine based on WeiChai 6170 marine diesel engine was established.The particle swarm optimization algorithm was used to achieve multi-input and multi-objective comprehensive optimization,and the effects of EGR-coupled Miller regulation and high-pressure turbine bypass regulation on NO_(x)and BSFC were investigated.The results showed that a medium EGR rate-coupled medium Miller degree was better for the comprehensive optimization of NO_(x)and BSFC.At medium EGR rate and low turbine bypass rates,NO_(x)and BSFC were relatively balanced and acceptable.Finally,an optimal steady-state control strategy under full loads was proposed.With an increase in loads,the optimized turbine bypass rate and Miller degree gradually increased.Compared with the EGRonly system,the optimal system of EGR and Miller cycle coupled turbine bypass reduced NO_(x)by 0.87 g/(kW·h)and BSFC by 17.19 g/(kW·h)at 100%load.Therefore,the EGR and Miller cycle coupled adjustable two-stage turbocharging achieves NO_(x)and BSFC optimization under full loads.
基金This project was supported by the National Natural Science Foundation of China (60272099) .
文摘A new faster block-matching algorithm （BMA） by using both search candidate and pixd sulzsamplings is proposed. Firstly a pixd-subsampling approach used in adjustable partial distortion search （APDS） is adjusted to visit about half points of all search candidates by subsampling them, using a spiral-scanning path with one skip. Two sdected candidates that have minimal and second minimal block distortion measures are obtained. Then a fine-tune step is taken around them to find the best one. Some analyses are given to approve the rationality of the approach of this paper. Experimental results show that, as compared to APDS, the proposed algorithm can enhance the block-matching speed by about 30% while maintaining its MSE performance very close to that of it. And it performs much better than many other BMAs such as TSS, NTSS, UCDBS and NPDS.
