Heavy-payload forging manipulators are mainly characterized by large load output and large capacitive-load input.The relationship between outputs and inputs,which will greatly influence the control and the reliability...Heavy-payload forging manipulators are mainly characterized by large load output and large capacitive-load input.The relationship between outputs and inputs,which will greatly influence the control and the reliability,is the key issue in type design for heavy-payload forging manipulators.In this paper,a type design method by considering the incidence relationship between output characteristics and actuator inputs is presented and used to design the mechanism for forging manipulators.The concept of modeling method based on the outputs tasks is defined and investigated.The principle of type design from the viewpoints of the relationship between output characteristics and actuator inputs is discussed.An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed.The incidence relationship matrix between outputs and inputs is also given.The design flow is obtained,and the incidence relationship between outputs and inputs for heavy-payload forging manipulators is divided into three parts after detailed understanding of the functional properties.Four types of mechanisms for heavy-payload forging manipulators are given,and the corresponding spatial mechanical sketches are also drawn,some new designed mechanisms have been adopted by company or used as prototype.These novel forging manipulators which satisfy certain functional requirements provide an effective help for the design of forging manipulators and patent application.展开更多
The traditional combinatorial designs can be used as basic designs for constructing designs of computer experiments which have been used successfully till now in various domains such as engineering, pharmaceutical ind...The traditional combinatorial designs can be used as basic designs for constructing designs of computer experiments which have been used successfully till now in various domains such as engineering, pharmaceutical industry, etc. In this paper, a new series of generalized partially balanced incomplete blocks PBIB designs with m associated classes (m = 4, 5 and 7) based on new generalized association schemes with number of treatments v arranged in w arrays of n rows and l columns (w ≥ 2, n ≥ 2, l ≥ 2) is defined. Some construction methods of these new PBIB are given and their parameters are specified using the Combinatory Method (s). For n or l even and s divisor of n or l, the obtained PBIB designs are resolvable PBIB designs. So the Fang RBIBD method is applied to obtain a series of particular U-type designs U (wnl;) (r is the repetition number of each treatment in our resolvable PBIB design).展开更多
The objective of this paper is to study the issue of uniformity on three-level U-type designs in terms of the wrap-around L2-discrepancy.Based on the known formula,we present a new lower bound of wrap-around L2-discre...The objective of this paper is to study the issue of uniformity on three-level U-type designs in terms of the wrap-around L2-discrepancy.Based on the known formula,we present a new lower bound of wrap-around L2-discrepancy for three-level U-type designs and compare it with those existing ones through figures,numerical simulation and illustrative examples.展开更多
Tower, Spar platform and mooring system are designed in the project based on a given 6-MW wind turbine. Under wind-induced only, wave-induced only and combined wind and wave induced loads, dynamic response is analyzed...Tower, Spar platform and mooring system are designed in the project based on a given 6-MW wind turbine. Under wind-induced only, wave-induced only and combined wind and wave induced loads, dynamic response is analyzed for a 6-MW Spar-type floating offshore wind turbine （FOWT） under operating conditions and parked conditions respectively. Comparison with a platform-fixed system （land-based system） ofa 6-MW wind turbine is carried out as well. Results demonstrate that the maximal out-of-plane deflection of the blade of a Spar-type system is 3.1% larger than that of a land-based system; the maximum response value of the nacelle acceleration is 215% larger for all the designed load cases being considered; the ultimate tower base fore-aft bending moment of the Spar-type system is 92% larger than that of the land-based system in all of the Design Load Cases （DLCs） being considered; the fluctuations of the mooring tension is mainly wave-induced, and the safety factor of the mooring tension is adequate for the 6-MW FOWT. The results can provide relevant modifications to the initial design for the Spar-type system, the detailed design and model basin test of the 6-MW Spar-type system.展开更多
This paper presents the design and implementation of a 3 kVA three-phase active T-type neutral-point clamped (NPC) inverter with GaN power devices for low-voltage microgrids. The designed inverter is used in a battery...This paper presents the design and implementation of a 3 kVA three-phase active T-type neutral-point clamped (NPC) inverter with GaN power devices for low-voltage microgrids. The designed inverter is used in a battery-based energy system (BESS) for power conversion optimization in applications to low-voltage microgrids. A modular design method has been developed for the design and implementation of the AT-NPC inverter. Experimental verification has been carried out based on a 3-kW three-phase T-Type NPC grid-connected inverter. FPGA based digital control technique has been developed for the current control of the three-level three-phase grid inverter. A maximum efficiency of 98.49% has been achieved within a load range from 50% to 75%.展开更多
The influences of the ratio of the radius of atom A（rA） to radius of atom B（rB）, electronegativity and electron number were discussed on the Laves phase formation and the characteristics of Zr-based AB2 type hydro...The influences of the ratio of the radius of atom A（rA） to radius of atom B（rB）, electronegativity and electron number were discussed on the Laves phase formation and the characteristics of Zr-based AB2 type hydrogen storage alloy. An enthalpy model of Zr-based AB2 alloy was obtained from known data and twelve Zr-based alloys were designed to test the model. The results show that the predicted values are in good agreement with the experimental values. The model can be used for predicting enthalpy values of Zr-based hydrogen storage alloys and settles a foundation for experiments.展开更多
New type professional farmers are farmers who possess certain resources and capitals,have certain extent of spirit of entrepreneurship,and are fully capable of obtaining and allocating resources related to agricultura...New type professional farmers are farmers who possess certain resources and capitals,have certain extent of spirit of entrepreneurship,and are fully capable of obtaining and allocating resources related to agricultural production and management,and engaged in agricultural production and management for obtaining average profit.Cultivation of new type professional farmers should be promoted in the process and at the background of"coordinated development of industrialization,informationization,urbanization and agricultural modernization".It should establish a proper cultivation subject system consisting of government,enterprises,rural communities and nonprofit organizations.Relying on multiple motive forces,efforts should be concentrated on cultivating those farmers with enterprising,highly innovative and learning ability,to guide traditional farmers to change into learning,enterprising and innovative ones.In addition,cultivation of new type professional farmers must rely on farmer education and training,modern agricultural development,increase in agricultural comparative advantage,innovation of rural management system and mechanism,multiple types of agricultural operation on a fairly large scale,as well as construction and regulation of new rural communities.Finally,it is recommended to provide system guarantee from long-term input mechanism of new type professional farmer education and training,incentive and restrictive mechanism of new type professional farmer cultivation,and construction of favorable environment for agricultural entrepreneurship.展开更多
Based on the method of compound and additional conditions under the conditions of the equal temperature rise and the equal potential drop (P.D.) of resistance, the application of design software of dry-type air-core r...Based on the method of compound and additional conditions under the conditions of the equal temperature rise and the equal potential drop (P.D.) of resistance, the application of design software of dry-type air-core reactor is introduced in this thesis. The analytical methods of the inductance are also given. This approach is proved entirely feasible in theory through the simplification with Bartky transformation, and is able to quickly and accurately calculate reactor inductance. This paper presents the analytical methods of the loss of dry-type air-core reactor as well.展开更多
Production of petrochemical catalysts accounts for one of the largest shares of platinum group metals(PGMs) consumption;thus,recycling of spent petrochemical catalysts holds great economic value.Conventionally,PGMs ar...Production of petrochemical catalysts accounts for one of the largest shares of platinum group metals(PGMs) consumption;thus,recycling of spent petrochemical catalysts holds great economic value.Conventionally,PGMs are recovered through hydrometallurgical processes which have a low recovery efficiency and produce a large amount of waste.In this regard,this paper proposed a method to use iron-capturing PGMs based on CaO-Al_(2)O_(3)-Na_(2)O slag.This method avoided the formation of Fe-Si alloy and achieved efficient enrichment of PGMs.The droplet force model showed that the recovery efficiency of PGMs could be improved if the slag had low density and low viscosity.Based on this result,FactSage software optimized the composition of slag.Furthermore,the effect of B_(2)O_(3) on the 1400 ℃ liquidus of CaO-Al_(2)O_(3)-Na_(2)O_(3)-B_(2)O_(3) phase diagram was revealed.Moreover,it was found that the recovery efficiency of PGMs exceeded 99% under the following optimized conditions:basicity of 1.0,20 wt%Na_(2)O,15 wt% B_(2)O_(3),15 wt% Fe,3 wt% C and a temperature range of 1400-1500℃.The thermodynamic model revealed the mechanism of iron capture.Different chemical bonds prevented the formation of bonds between the alloy and slag,resulting in the separation of the slag from the alloy.PGMs particles and iron microspheres had significant surface Gibbs free energy.Only when iron microspheres and PGMs particles collided and fused with each other to reduce their surface area could the Gibbs free energy of the system be reduced.展开更多
After illustration of research and development process of sightseeing agricultural park,the paper had classified sightseeing agricultural park into sightseeing agricultural park,education agricultural park and agricul...After illustration of research and development process of sightseeing agricultural park,the paper had classified sightseeing agricultural park into sightseeing agricultural park,education agricultural park and agricultural garden in terms of development content;into renovation type and newly-built type in accordance with development mode;and into plain type and mountainous type in the light of terrain.From the perspectives of terrain,vegetation,hydrology and ecology,characteristics of landscape resources in mountainous sightseeing agricultural park were analyzed.It proposed principles for planning and design of mountainous sightseeing agricultural park,which were respecting and protecting nature,linking landscape units and coordinating spatial structure,systematicness and protecting inheritance of traditional culture.On this basis,it had illustrated landscape designing theories on architecture and landscape furniture,traffic road,plant greening and water supply and sewerage works.展开更多
基金supported by National Key Basic Research Program of China (973 Program,Grant No. 2006CB705402)Important National Science & Technology Specific Projects (Grant No. 2009ZX04002-061)National Hi-tech Research and Development Program of China (863Program,Grant No. 2008AA04XK1478950)
文摘Heavy-payload forging manipulators are mainly characterized by large load output and large capacitive-load input.The relationship between outputs and inputs,which will greatly influence the control and the reliability,is the key issue in type design for heavy-payload forging manipulators.In this paper,a type design method by considering the incidence relationship between output characteristics and actuator inputs is presented and used to design the mechanism for forging manipulators.The concept of modeling method based on the outputs tasks is defined and investigated.The principle of type design from the viewpoints of the relationship between output characteristics and actuator inputs is discussed.An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed.The incidence relationship matrix between outputs and inputs is also given.The design flow is obtained,and the incidence relationship between outputs and inputs for heavy-payload forging manipulators is divided into three parts after detailed understanding of the functional properties.Four types of mechanisms for heavy-payload forging manipulators are given,and the corresponding spatial mechanical sketches are also drawn,some new designed mechanisms have been adopted by company or used as prototype.These novel forging manipulators which satisfy certain functional requirements provide an effective help for the design of forging manipulators and patent application.
文摘The traditional combinatorial designs can be used as basic designs for constructing designs of computer experiments which have been used successfully till now in various domains such as engineering, pharmaceutical industry, etc. In this paper, a new series of generalized partially balanced incomplete blocks PBIB designs with m associated classes (m = 4, 5 and 7) based on new generalized association schemes with number of treatments v arranged in w arrays of n rows and l columns (w ≥ 2, n ≥ 2, l ≥ 2) is defined. Some construction methods of these new PBIB are given and their parameters are specified using the Combinatory Method (s). For n or l even and s divisor of n or l, the obtained PBIB designs are resolvable PBIB designs. So the Fang RBIBD method is applied to obtain a series of particular U-type designs U (wnl;) (r is the repetition number of each treatment in our resolvable PBIB design).
基金Supported in part by the National Natural Science Foundation of China(Nos.11871237,11801576,11271147,11401596)the Fundamental Research Funds for the Central Universities(South-Central University for Nationalities(Nos.CZQ18017,CZQ19010))
文摘The objective of this paper is to study the issue of uniformity on three-level U-type designs in terms of the wrap-around L2-discrepancy.Based on the known formula,we present a new lower bound of wrap-around L2-discrepancy for three-level U-type designs and compare it with those existing ones through figures,numerical simulation and illustrative examples.
基金financially supported by the National Basic Research Program of China(973 Program,Grant No.2014CB046205)
文摘Tower, Spar platform and mooring system are designed in the project based on a given 6-MW wind turbine. Under wind-induced only, wave-induced only and combined wind and wave induced loads, dynamic response is analyzed for a 6-MW Spar-type floating offshore wind turbine （FOWT） under operating conditions and parked conditions respectively. Comparison with a platform-fixed system （land-based system） ofa 6-MW wind turbine is carried out as well. Results demonstrate that the maximal out-of-plane deflection of the blade of a Spar-type system is 3.1% larger than that of a land-based system; the maximum response value of the nacelle acceleration is 215% larger for all the designed load cases being considered; the ultimate tower base fore-aft bending moment of the Spar-type system is 92% larger than that of the land-based system in all of the Design Load Cases （DLCs） being considered; the fluctuations of the mooring tension is mainly wave-induced, and the safety factor of the mooring tension is adequate for the 6-MW FOWT. The results can provide relevant modifications to the initial design for the Spar-type system, the detailed design and model basin test of the 6-MW Spar-type system.
文摘This paper presents the design and implementation of a 3 kVA three-phase active T-type neutral-point clamped (NPC) inverter with GaN power devices for low-voltage microgrids. The designed inverter is used in a battery-based energy system (BESS) for power conversion optimization in applications to low-voltage microgrids. A modular design method has been developed for the design and implementation of the AT-NPC inverter. Experimental verification has been carried out based on a 3-kW three-phase T-Type NPC grid-connected inverter. FPGA based digital control technique has been developed for the current control of the three-level three-phase grid inverter. A maximum efficiency of 98.49% has been achieved within a load range from 50% to 75%.
文摘The influences of the ratio of the radius of atom A（rA） to radius of atom B（rB）, electronegativity and electron number were discussed on the Laves phase formation and the characteristics of Zr-based AB2 type hydrogen storage alloy. An enthalpy model of Zr-based AB2 alloy was obtained from known data and twelve Zr-based alloys were designed to test the model. The results show that the predicted values are in good agreement with the experimental values. The model can be used for predicting enthalpy values of Zr-based hydrogen storage alloys and settles a foundation for experiments.
基金Supported by Key Project of National Social Science Foundation(10AGL007&12ASH004)Key Project of Ministry of Education(DFA100209)+2 种基金Ph.D.Foundation Project of Southwest University(SWU1209338)Fundamental Research Funds for the Central Universities in 2013(SWU1309315)Fundamental Research Funds for the Central Universities in 2009(SWU0909629)
文摘New type professional farmers are farmers who possess certain resources and capitals,have certain extent of spirit of entrepreneurship,and are fully capable of obtaining and allocating resources related to agricultural production and management,and engaged in agricultural production and management for obtaining average profit.Cultivation of new type professional farmers should be promoted in the process and at the background of"coordinated development of industrialization,informationization,urbanization and agricultural modernization".It should establish a proper cultivation subject system consisting of government,enterprises,rural communities and nonprofit organizations.Relying on multiple motive forces,efforts should be concentrated on cultivating those farmers with enterprising,highly innovative and learning ability,to guide traditional farmers to change into learning,enterprising and innovative ones.In addition,cultivation of new type professional farmers must rely on farmer education and training,modern agricultural development,increase in agricultural comparative advantage,innovation of rural management system and mechanism,multiple types of agricultural operation on a fairly large scale,as well as construction and regulation of new rural communities.Finally,it is recommended to provide system guarantee from long-term input mechanism of new type professional farmer education and training,incentive and restrictive mechanism of new type professional farmer cultivation,and construction of favorable environment for agricultural entrepreneurship.
文摘Based on the method of compound and additional conditions under the conditions of the equal temperature rise and the equal potential drop (P.D.) of resistance, the application of design software of dry-type air-core reactor is introduced in this thesis. The analytical methods of the inductance are also given. This approach is proved entirely feasible in theory through the simplification with Bartky transformation, and is able to quickly and accurately calculate reactor inductance. This paper presents the analytical methods of the loss of dry-type air-core reactor as well.
基金financially supported by the National Natural Science Foundation of China (Nos.U2002212 and 52204412)the National Key R&D Program of China (Nos. 2019YFC1907101,2019YFC1907103 and 2021YFC1910504)+3 种基金Key R&D Program of Ningxia Hui Autonomous Region (No. 2020BCE01001)Guangdong Basic and Applied Basic Research Foundation (No.2020A1515110408)Foshan Science and Technology Innovation Special Foundation (No.BK21BE002)the Fundamental Research Funds for the Central Universities (No.FRF-TP20-031A1)。
文摘Production of petrochemical catalysts accounts for one of the largest shares of platinum group metals(PGMs) consumption;thus,recycling of spent petrochemical catalysts holds great economic value.Conventionally,PGMs are recovered through hydrometallurgical processes which have a low recovery efficiency and produce a large amount of waste.In this regard,this paper proposed a method to use iron-capturing PGMs based on CaO-Al_(2)O_(3)-Na_(2)O slag.This method avoided the formation of Fe-Si alloy and achieved efficient enrichment of PGMs.The droplet force model showed that the recovery efficiency of PGMs could be improved if the slag had low density and low viscosity.Based on this result,FactSage software optimized the composition of slag.Furthermore,the effect of B_(2)O_(3) on the 1400 ℃ liquidus of CaO-Al_(2)O_(3)-Na_(2)O_(3)-B_(2)O_(3) phase diagram was revealed.Moreover,it was found that the recovery efficiency of PGMs exceeded 99% under the following optimized conditions:basicity of 1.0,20 wt%Na_(2)O,15 wt% B_(2)O_(3),15 wt% Fe,3 wt% C and a temperature range of 1400-1500℃.The thermodynamic model revealed the mechanism of iron capture.Different chemical bonds prevented the formation of bonds between the alloy and slag,resulting in the separation of the slag from the alloy.PGMs particles and iron microspheres had significant surface Gibbs free energy.Only when iron microspheres and PGMs particles collided and fused with each other to reduce their surface area could the Gibbs free energy of the system be reduced.
文摘After illustration of research and development process of sightseeing agricultural park,the paper had classified sightseeing agricultural park into sightseeing agricultural park,education agricultural park and agricultural garden in terms of development content;into renovation type and newly-built type in accordance with development mode;and into plain type and mountainous type in the light of terrain.From the perspectives of terrain,vegetation,hydrology and ecology,characteristics of landscape resources in mountainous sightseeing agricultural park were analyzed.It proposed principles for planning and design of mountainous sightseeing agricultural park,which were respecting and protecting nature,linking landscape units and coordinating spatial structure,systematicness and protecting inheritance of traditional culture.On this basis,it had illustrated landscape designing theories on architecture and landscape furniture,traffic road,plant greening and water supply and sewerage works.
