A borderless art form,film shoulders a mission of sharing culture and fostering emotional bonds.In the relationship between China and Thailand,cinema has long served as a vital cultural bridge,uniting the hearts and m...A borderless art form,film shoulders a mission of sharing culture and fostering emotional bonds.In the relationship between China and Thailand,cinema has long served as a vital cultural bridge,uniting the hearts and minds of the two peoples.From the screening of Chinese films in Thailand to the deepening collaboration within the film industry,the history of bilateral cinematic exchange not only showcases the unique value of film as a cultural medium but also reflects the resilience and vitality of grassroots cultural interactions amid a complex international landscape.This shared history,marked by both challenges and triumphs,has laid a solid foundation for future cultural cooperation,becoming a memorable chapter in the narrative of China-Thailand relations.展开更多
The first China International Supply Chain Expo provided a perfect platform for strengthening the safety and stability of global industrial and supply chains.THE first China International Supply Chain Expo(CISCE)theme...The first China International Supply Chain Expo provided a perfect platform for strengthening the safety and stability of global industrial and supply chains.THE first China International Supply Chain Expo(CISCE)themed“connecting the world for a shared future”kicked off in Beijing on November 28,2023.The world’s first national-level exhibition with supply chains as its theme,the expo was divided into five areas representing five major supply chains and related services-smart vehicles,green agriculture,clean energy,digital technology,and healthy life.It also had a supply chain service exhibition area.展开更多
This article studies the educational mode connecting vocational education and undergraduate education in finance and accounting majors,in response to the weak cultural foundation and poor course integration faced by c...This article studies the educational mode connecting vocational education and undergraduate education in finance and accounting majors,in response to the weak cultural foundation and poor course integration faced by current vocational school graduates after entering vocational undergraduate education.By adopting empirical research methods and selecting vocational college students majoring in finance and accounting and ordinary high school students as research objects,this study implements a series of teaching reform measures and conducts tracking surveys on the short-term and long-term effects of educational reforms.As a result,it was found that in the final survey of graduation destinations,34 vocational and technical college students were engaged in related work in their majors,accounting for 45.9%of all vocational and technical college students.This proves that the proposed transitional education model can effectively enhance the cultural foundation of vocational college students and provide new ideas for the cultivation of talents in finance and accounting majors.展开更多
Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properti...Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.展开更多
The China-proposed Global Civilisation Initiative(GCl)holds immense potential to shape a harmonious world through cultural connectivity,greater cooperation and mutual respect among nations,a former Pakistani Minister ...The China-proposed Global Civilisation Initiative(GCl)holds immense potential to shape a harmonious world through cultural connectivity,greater cooperation and mutual respect among nations,a former Pakistani Minister said.Cultural connectivity encourages inclusive coexistence and deters aggression by promoting mutual respect and understanding.By advocating these values,the GCl has inspired a new era of unity,understanding and peaceful coexistence on a global scale,Syed Jamal Shah,former Pakistan Minister for National Heritage and Culture,told Xinhua in a recent interview.展开更多
Flange joint part is the weak link of wind turbine tower.In view of the special structure,complex stress and easy failure of the connecting bolt of the wind turbine tower flange,the relationship between the external l...Flange joint part is the weak link of wind turbine tower.In view of the special structure,complex stress and easy failure of the connecting bolt of the wind turbine tower flange,the relationship between the external load of the tower section and the internal stress of the bolt is established by the finite element method,and the time series internal stress of the bolt is calculated by the Schmidt-Neuper algorithm.The S-N curve which is suitable for the connecting bolt material of the tower flange is selected by the GL2010 specification.On the basis of Miner’s fatigue cumulative damage theory and rain flow counting method,the fatigue strength of the whole ring bolt is roughly calculated,and the most dangerous part is determined.The axial symmetry model of screw connection is used for accurately calculating the fatigue cumulative damage of the bolt at the dangerous part.The results show that the fatigue life of the bolts in the most dangerous position can meet the requirements,the engineering algorithm has advantages in determining the dangerous part of the whole ring bolt,and the finite element method has high accuracy in predicting the fatigue life of the bolts in the dangerous part.The proposed method is feasible and effective in predicting the fatigue life of the flange joint bolts of the tower.展开更多
The effect of through-thickness reinforcement by composite pins （Z-pins） on the static tensile strength and failure mechanisms of the joints made from ceramic matrix composite （CMC） is investigated. Overlap length...The effect of through-thickness reinforcement by composite pins （Z-pins） on the static tensile strength and failure mechanisms of the joints made from ceramic matrix composite （CMC） is investigated. Overlap length of the single lap joint is 15 mm, 20 mm, 23 mm, 37 mm, and 60 mm, respectively. The experimental results indicate that the final failure modes of the joints can be divided into two groups, （a） the bond-line stops debonding until crack encounters Z-pins; and then the adherends break at the location of Z-pins, when overlap length is more than 20 mm; （b） the bond-line detaches entirely and Z-pins are drawn from adherends, when overlap length is equal to 15 mm. A simple efficient computational approach is presented for analyzing the benefit of through-thickness pins for restricting failure in the single lap joints. Here, the mechanics problem is simplified by representing the effect of the pins by tractions acting on the fracture surfaces of the cracked bond-line. The tractions are prescribed as functions of the crack displacement, which are available in simple forms that summarize the complex deformations to a reasonable accuracy. The resulting model can be used to track the evolution of complete failure mechanisms, for example, bond-line initial delamination and ultimate failure associated with Z-pin pullout, ultimate failure of the adherends. The paper simulates connecting performance of the single lap joints with different Z-pins＇ diameter, spacing and overlap length; the numerical results agree with the experimental results; the numerical results indicate enlarging diameter and decreasing spacing of Z-pins are in favor of improving the connecting performance of the joints. By numerical analysis method, the critical overlap length that lies between two final failure modes is between 18 mm and 19 mm, when Z-pins＇ diameter and spacing are 0.4 mm, 5 mm, respectively.展开更多
On the basis of expounding the research results of using relevant knowledge about Game Theory for supply chain of agricultural products at home and abroad,we use principal-agent model in Game Theory to research the ne...On the basis of expounding the research results of using relevant knowledge about Game Theory for supply chain of agricultural products at home and abroad,we use principal-agent model in Game Theory to research the new function that the supermarkets entrust supervision and control over quality of agricultural products to agricultural brokers in the circulation model of connecting agriculture with supermarkets;then design the optimal incentive contract and influencing factors between agricultural broker and supermarket,and explain the fundamental role of agricultural brokers in the process of circulation;finally in light of the role of government in promoting development and application of agricultural brokers,put forward corresponding policy suggestions:establish government support policy;set relevant standard of industry;establish cooperative organizations of agricultural brokers.展开更多
Based on the engineering background of the contact channel between Shangyang and Gushan of Fuzhou Metro Line 2 undercrossing the existing tunnel line,the freezing temperature field of the contact channel,the displacem...Based on the engineering background of the contact channel between Shangyang and Gushan of Fuzhou Metro Line 2 undercrossing the existing tunnel line,the freezing temperature field of the contact channel,the displacement field of the existing tunnel line and the contact channel with different net distances and horizontal angles are analyzed by ANSYS finite element software and field measurement method.The obtained results indicate that during the freezing period,the temperature drops at different measuring holes are almost the same.The temperature near the bottom freezing tube drops faster than that far from the tube.It is found that the bilateral freezing technique improves the formation of the freezing wall in the intersection area.In this case,the intersection time of the cross-section is 7 days faster than that of the adjacent ordinary section.The change curve of the displacement of the surface uplift in different freezing periods with the distance from the center of the channel is“M”shaped.The maximum uplift displacement at 12 m from channel center is 25 mm.The vertical displacement of the measuring point located above the central axis of the connecting channel is large.The farther the point from the central axis,the smaller the corresponding vertical displacement.When the horizontal angle between the existing tunnel and the connecting channel is less than 60,the existing vertical displacement of the tunnel changes rapidly with the horizontal angle,reaching 0.17 mm/.Meanwhile,when the net distance is less than 6.1 m,the change rate of the vertical displacement of the tunnel is up to 2.4 mm/m.展开更多
The growth behaviour of austenite grain in a V-N microalloyed medium carbon steel and its effect on splitting fracture property were investigated by mechanical tests, fracture morphology and microstructure analysis. W...The growth behaviour of austenite grain in a V-N microalloyed medium carbon steel and its effect on splitting fracture property were investigated by mechanical tests, fracture morphology and microstructure analysis. When the heating temperature is 800℃, the austenite grain size is 7.6 μm, and the fracture surface is uneven with the impact energy of 235.9 J. When the heating temperature increases to 1100 ℃, the austenite grain size grows up to 65.5 μm and the impact fracture surface is much more even with the impact energy of 13.6 J. It is believed that the coarse austenite grain size of 65.5 μm is beneficial for the splitting fracture property of V-N microalloyed medium carbon steel connecting rod. In addition, austenite grain sizes of V-N microalloyed medium carbon steel increase with the increasing in heating tem-perature and holding time. Then, a grain growth model is established to predict austenite grain growth behaviour.展开更多
Based on a simplified 3-DOF model of twin-tower structure linked by a sky-bridge,the frequency response functions,the displacement power spectral density(PSD)functions,and the time-averaged total vibration energy were...Based on a simplified 3-DOF model of twin-tower structure linked by a sky-bridge,the frequency response functions,the displacement power spectral density(PSD)functions,and the time-averaged total vibration energy were derived,by assuming the white noise as the earthquake excitation.The effects of connecting parameters,such as linking stiffness ratio and linking damping ratio,on the structural vibration responses were then studied,and the optimal connecting parameters were obtained to minimize the vibration energy of either the independent monomer tower or the integral structure.The influences of sky-bridge elevation position on the optimal connecting parameters were also discussed.Finally,the distribution characteristics of the top displacement PSD and the structural responses,excited by El Centro,Taft and artificial waves,were compared in both frequency and time domain.It is found that the connecting parameters at either end of connection interactively affect the responses of the towers.The optimal connecting parameters can greatly improve the damping connections on their seismic reduction effectiveness,but are unable to reduce the seismic responses of the towers to the best extent simultaneously.It is also indicated that the optimal connecting parameters derived from the simplified 3-DOF model are applicable for two multi-story structures linked by a sky-bridge with dampers.The seismic reduction effectiveness obtained varies from 0.3 to 1.0 with different sky-bridge mass ratio.The displacement responses of the example structures are reduced by approximately 22% with sky-bridge connections.展开更多
Based on the inner character analysis of interpart, detail modification andassembly relation of mechanical connecting element, the idea, which extends the feature modeling ofpart to the interpart feature modeling for ...Based on the inner character analysis of interpart, detail modification andassembly relation of mechanical connecting element, the idea, which extends the feature modeling ofpart to the interpart feature modeling for assembly purpose, is presented, and virtual-part-basedconnecting element modeling is proposed. During the assembly modeling, base parts are modified bythe Boolean subtraction between the virtual part and the part to be connected. Dynamic matchingalgorithm, which is based on list database, is designed for dynamic extension and off-line editingof connecting part and virtual part, and design rules of connecting element is encapsulated by thevirtual part. A prototyped software module for rapid design of connecting elements is implementedunder self-developed CAD/CAM platform-SuperMan.展开更多
Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the p...Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF（User Defined Function） command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.展开更多
The Clauser Horne--Shimony-Holt-type noncontextuality inequality and the Svetliehny inequality are derived from the Alicki-van Ryn quantumness witness. Thus connections between quantumness and quantum contextuality, a...The Clauser Horne--Shimony-Holt-type noncontextuality inequality and the Svetliehny inequality are derived from the Alicki-van Ryn quantumness witness. Thus connections between quantumness and quantum contextuality, and between quantumness and genuine multipartite nonlocality are established.展开更多
In the past decades several theoretical Maxwell＇s demon models have been proposed to exhibit effects such as refrigerating, doing work at the cost of information, and some experiments have been carried out to realize...In the past decades several theoretical Maxwell＇s demon models have been proposed to exhibit effects such as refrigerating, doing work at the cost of information, and some experiments have been carried out to realize these effects. We propose a model with a two-level demon, information represented by a sequence of bits, and two heat reservoirs. The reservoir that the demon is interacting with depends on the bit. When the temperature difference between the two heat reservoirs is large enough, the information can be erased. On the other hand, when the information is pure enough, heat transfer from one reservoir to the other can happen, resulting in the effect of refrigeration. Genuine examples of such a system are discussed.展开更多
Photoplastic experiment were conducted with connecting rods of AX100 motorcycle engine during finish forging to investigate material plastic flow law of long -axis forgings with comples geometrie’s by observing
The intensive competition of automotive market requ ir es shortening the product development circle and improving the product quality. Many of auto manufacturers in china have introduced some CAD/CAE/CAM systems in pr...The intensive competition of automotive market requ ir es shortening the product development circle and improving the product quality. Many of auto manufacturers in china have introduced some CAD/CAE/CAM systems in product development process, and have got some success. But the special and effi cient CAD system aimed at particular product is absent. This paper provides a CA D/CAE system that can realize the integration of CAD and CAE process for engine connecting rod development. The paper discusses some general methods in connecting rod design process, and s ums up structure characteristics of connecting rod. It introduces feature defini tion and feature classification facing connecting rod CAD/CAE system. Based on t he study of the feature technology and the feature of connecting rod, it creates the feature information model and feature database of engine connecting rod . In addition, it creates the parametric model of engine connection rod and real izes variable parametric design and variable structure design. With the help of Pro/Toolkit and Using C++ program to call the user ’s toolbox of Pro/ Engineer software system, the connecting rod CAD/CAE syst em can create connecting rod model automatically to meet the needs of different structure and different type of connecting rod. Based on Pro/Mechanica platform of PTC, the system can implements the Finite Ele ment Analysis and optimization of the connecting rod. Because using the same database in design and analysis, no data lost and no error occurs during da ta transforming. Using the connecting rod CAD/CAE system, the connecting rod can be meshed automatically and the FEA result can be achieved very fast and is very similar to the experiment. In a word, the connecting rod CAD/CAE system developed in this paper can optimiz e the product development process, realize the data share and concurrent enginee ring in the product design and analysis process, shorten the product develop ment circle, and improve the efficiency.展开更多
A motorcycle connecting rod is one of the major moving parts affecting the engine performance. The traditional manufacturing process results in material waste and excessive machining. A new method of hot forging P/M h...A motorcycle connecting rod is one of the major moving parts affecting the engine performance. The traditional manufacturing process results in material waste and excessive machining. A new method of hot forging P/M has been proposed and studied experimentally. In order to achieve uniform density, the punch was divided into three parts to consolidate the loose powder. The multistage movement of the three parts of the punch, called synchronous compaction, results in the desired uniform density. Powder flow during consolidation was illustrated and the density distribution of the compacts was measured. A set of forging dies with flash was used to produce densification and deformation of the sintered compact. Then a set of flashless forging dies was designed to obtain the desired shape and dimensions of the connecting rod. The effects of forging temperature and initial compact density on densification were evaluated through hot forging experiments. Based on properties achieved, Fe-C-Cu-Mo was selected as the展开更多
In order to obtain the desired mechanical properties of connecting bar after quenching and tempering,and reduce the cracking tendency and distortion,a program of controllable quenching was established.Furthermore,a co...In order to obtain the desired mechanical properties of connecting bar after quenching and tempering,and reduce the cracking tendency and distortion,a program of controllable quenching was established.Furthermore,a computer-aided quenching (CAQ) system was developed.The applications show satisfactory results.展开更多
To solve the optimal solution of some issues in applied science, studying of connecting conditions, constraint conditions and constraint equations is made. This paper cites an example in point in vibration mechanics a...To solve the optimal solution of some issues in applied science, studying of connecting conditions, constraint conditions and constraint equations is made. This paper cites an example in point in vibration mechanics and seeks the connecting conditions and constraint equations of high speed compound rotating system. This paper points out that the selection of the boundary conditions or connection conditions can effect on the optimal solution of the issue as soon as the object function is determined.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(No.2022JJ037).
文摘A borderless art form,film shoulders a mission of sharing culture and fostering emotional bonds.In the relationship between China and Thailand,cinema has long served as a vital cultural bridge,uniting the hearts and minds of the two peoples.From the screening of Chinese films in Thailand to the deepening collaboration within the film industry,the history of bilateral cinematic exchange not only showcases the unique value of film as a cultural medium but also reflects the resilience and vitality of grassroots cultural interactions amid a complex international landscape.This shared history,marked by both challenges and triumphs,has laid a solid foundation for future cultural cooperation,becoming a memorable chapter in the narrative of China-Thailand relations.
文摘The first China International Supply Chain Expo provided a perfect platform for strengthening the safety and stability of global industrial and supply chains.THE first China International Supply Chain Expo(CISCE)themed“connecting the world for a shared future”kicked off in Beijing on November 28,2023.The world’s first national-level exhibition with supply chains as its theme,the expo was divided into five areas representing five major supply chains and related services-smart vehicles,green agriculture,clean energy,digital technology,and healthy life.It also had a supply chain service exhibition area.
基金2024 Project of Chengdu Vocational and Undergraduate Education Association“Research on the Curriculum System Convergence of‘Vocational Education-Undergraduate Education’in Financial and Accounting Majors Based on the Progressive Development of Vocational Competence”(GZZZ2024-15)。
文摘This article studies the educational mode connecting vocational education and undergraduate education in finance and accounting majors,in response to the weak cultural foundation and poor course integration faced by current vocational school graduates after entering vocational undergraduate education.By adopting empirical research methods and selecting vocational college students majoring in finance and accounting and ordinary high school students as research objects,this study implements a series of teaching reform measures and conducts tracking surveys on the short-term and long-term effects of educational reforms.As a result,it was found that in the final survey of graduation destinations,34 vocational and technical college students were engaged in related work in their majors,accounting for 45.9%of all vocational and technical college students.This proves that the proposed transitional education model can effectively enhance the cultural foundation of vocational college students and provide new ideas for the cultivation of talents in finance and accounting majors.
基金Project(51335009)supported by the National Natural Science Foundation of ChinaProject(2014JQ7273)supported by the Natural Science Foundation of Shaanxi Province of ChinaProject(CXY1514(1))supported by the Xi’an Science and Technology Plan Projects,China
文摘Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.
文摘The China-proposed Global Civilisation Initiative(GCl)holds immense potential to shape a harmonious world through cultural connectivity,greater cooperation and mutual respect among nations,a former Pakistani Minister said.Cultural connectivity encourages inclusive coexistence and deters aggression by promoting mutual respect and understanding.By advocating these values,the GCl has inspired a new era of unity,understanding and peaceful coexistence on a global scale,Syed Jamal Shah,former Pakistan Minister for National Heritage and Culture,told Xinhua in a recent interview.
基金the Special Research Fund for the Natural Science Foundation of Inner Mongolia Autonomous Region(No.2019MS05070)。
文摘Flange joint part is the weak link of wind turbine tower.In view of the special structure,complex stress and easy failure of the connecting bolt of the wind turbine tower flange,the relationship between the external load of the tower section and the internal stress of the bolt is established by the finite element method,and the time series internal stress of the bolt is calculated by the Schmidt-Neuper algorithm.The S-N curve which is suitable for the connecting bolt material of the tower flange is selected by the GL2010 specification.On the basis of Miner’s fatigue cumulative damage theory and rain flow counting method,the fatigue strength of the whole ring bolt is roughly calculated,and the most dangerous part is determined.The axial symmetry model of screw connection is used for accurately calculating the fatigue cumulative damage of the bolt at the dangerous part.The results show that the fatigue life of the bolts in the most dangerous position can meet the requirements,the engineering algorithm has advantages in determining the dangerous part of the whole ring bolt,and the finite element method has high accuracy in predicting the fatigue life of the bolts in the dangerous part.The proposed method is feasible and effective in predicting the fatigue life of the flange joint bolts of the tower.
基金supported by the National Natural Science Foundation of China (No. 90405015)the Research Fund forthe Doctoral Program of Higher Education (No. 20030699040).
文摘The effect of through-thickness reinforcement by composite pins （Z-pins） on the static tensile strength and failure mechanisms of the joints made from ceramic matrix composite （CMC） is investigated. Overlap length of the single lap joint is 15 mm, 20 mm, 23 mm, 37 mm, and 60 mm, respectively. The experimental results indicate that the final failure modes of the joints can be divided into two groups, （a） the bond-line stops debonding until crack encounters Z-pins; and then the adherends break at the location of Z-pins, when overlap length is more than 20 mm; （b） the bond-line detaches entirely and Z-pins are drawn from adherends, when overlap length is equal to 15 mm. A simple efficient computational approach is presented for analyzing the benefit of through-thickness pins for restricting failure in the single lap joints. Here, the mechanics problem is simplified by representing the effect of the pins by tractions acting on the fracture surfaces of the cracked bond-line. The tractions are prescribed as functions of the crack displacement, which are available in simple forms that summarize the complex deformations to a reasonable accuracy. The resulting model can be used to track the evolution of complete failure mechanisms, for example, bond-line initial delamination and ultimate failure associated with Z-pin pullout, ultimate failure of the adherends. The paper simulates connecting performance of the single lap joints with different Z-pins＇ diameter, spacing and overlap length; the numerical results agree with the experimental results; the numerical results indicate enlarging diameter and decreasing spacing of Z-pins are in favor of improving the connecting performance of the joints. By numerical analysis method, the critical overlap length that lies between two final failure modes is between 18 mm and 19 mm, when Z-pins＇ diameter and spacing are 0.4 mm, 5 mm, respectively.
基金Supported by National College Students Innovation Program in 2009(091029532)
文摘On the basis of expounding the research results of using relevant knowledge about Game Theory for supply chain of agricultural products at home and abroad,we use principal-agent model in Game Theory to research the new function that the supermarkets entrust supervision and control over quality of agricultural products to agricultural brokers in the circulation model of connecting agriculture with supermarkets;then design the optimal incentive contract and influencing factors between agricultural broker and supermarket,and explain the fundamental role of agricultural brokers in the process of circulation;finally in light of the role of government in promoting development and application of agricultural brokers,put forward corresponding policy suggestions:establish government support policy;set relevant standard of industry;establish cooperative organizations of agricultural brokers.
基金This research was supported by the project of Natural Science Foundation of Fujian Province(No.2022J01925)supported by the project of the Fuzhou Science and Technology Plan Project(2021-P-047)supported by the Open Project Program Foundation of Engineering Research Center of underground mine construction,Ministry of Education(Anhui University of Science and Technology)(No.JYBGCZX2021104).
文摘Based on the engineering background of the contact channel between Shangyang and Gushan of Fuzhou Metro Line 2 undercrossing the existing tunnel line,the freezing temperature field of the contact channel,the displacement field of the existing tunnel line and the contact channel with different net distances and horizontal angles are analyzed by ANSYS finite element software and field measurement method.The obtained results indicate that during the freezing period,the temperature drops at different measuring holes are almost the same.The temperature near the bottom freezing tube drops faster than that far from the tube.It is found that the bilateral freezing technique improves the formation of the freezing wall in the intersection area.In this case,the intersection time of the cross-section is 7 days faster than that of the adjacent ordinary section.The change curve of the displacement of the surface uplift in different freezing periods with the distance from the center of the channel is“M”shaped.The maximum uplift displacement at 12 m from channel center is 25 mm.The vertical displacement of the measuring point located above the central axis of the connecting channel is large.The farther the point from the central axis,the smaller the corresponding vertical displacement.When the horizontal angle between the existing tunnel and the connecting channel is less than 60,the existing vertical displacement of the tunnel changes rapidly with the horizontal angle,reaching 0.17 mm/.Meanwhile,when the net distance is less than 6.1 m,the change rate of the vertical displacement of the tunnel is up to 2.4 mm/m.
文摘The growth behaviour of austenite grain in a V-N microalloyed medium carbon steel and its effect on splitting fracture property were investigated by mechanical tests, fracture morphology and microstructure analysis. When the heating temperature is 800℃, the austenite grain size is 7.6 μm, and the fracture surface is uneven with the impact energy of 235.9 J. When the heating temperature increases to 1100 ℃, the austenite grain size grows up to 65.5 μm and the impact fracture surface is much more even with the impact energy of 13.6 J. It is believed that the coarse austenite grain size of 65.5 μm is beneficial for the splitting fracture property of V-N microalloyed medium carbon steel connecting rod. In addition, austenite grain sizes of V-N microalloyed medium carbon steel increase with the increasing in heating tem-perature and holding time. Then, a grain growth model is established to predict austenite grain growth behaviour.
基金Project(51178203)supported by the National Natural Science Foundation of China
文摘Based on a simplified 3-DOF model of twin-tower structure linked by a sky-bridge,the frequency response functions,the displacement power spectral density(PSD)functions,and the time-averaged total vibration energy were derived,by assuming the white noise as the earthquake excitation.The effects of connecting parameters,such as linking stiffness ratio and linking damping ratio,on the structural vibration responses were then studied,and the optimal connecting parameters were obtained to minimize the vibration energy of either the independent monomer tower or the integral structure.The influences of sky-bridge elevation position on the optimal connecting parameters were also discussed.Finally,the distribution characteristics of the top displacement PSD and the structural responses,excited by El Centro,Taft and artificial waves,were compared in both frequency and time domain.It is found that the connecting parameters at either end of connection interactively affect the responses of the towers.The optimal connecting parameters can greatly improve the damping connections on their seismic reduction effectiveness,but are unable to reduce the seismic responses of the towers to the best extent simultaneously.It is also indicated that the optimal connecting parameters derived from the simplified 3-DOF model are applicable for two multi-story structures linked by a sky-bridge with dampers.The seismic reduction effectiveness obtained varies from 0.3 to 1.0 with different sky-bridge mass ratio.The displacement responses of the example structures are reduced by approximately 22% with sky-bridge connections.
基金This project is supported by High Technology Research and Development Program of China (No.2002A411030).
文摘Based on the inner character analysis of interpart, detail modification andassembly relation of mechanical connecting element, the idea, which extends the feature modeling ofpart to the interpart feature modeling for assembly purpose, is presented, and virtual-part-basedconnecting element modeling is proposed. During the assembly modeling, base parts are modified bythe Boolean subtraction between the virtual part and the part to be connected. Dynamic matchingalgorithm, which is based on list database, is designed for dynamic extension and off-line editingof connecting part and virtual part, and design rules of connecting element is encapsulated by thevirtual part. A prototyped software module for rapid design of connecting elements is implementedunder self-developed CAD/CAM platform-SuperMan.
基金financially supported by the State Oceanic Administration of China(Grant No.GHME2011CL01)the Program of State Key Laboratory of Coastal and Offshore Engineering(Grant No.LP1102)
文摘Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF（User Defined Function） command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921900the National Natural Science Foundation of China under Grant Nos 11175089 and 11475089
文摘The Clauser Horne--Shimony-Holt-type noncontextuality inequality and the Svetliehny inequality are derived from the Alicki-van Ryn quantumness witness. Thus connections between quantumness and quantum contextuality, and between quantumness and genuine multipartite nonlocality are established.
基金Supported by the National Basic Research Program of China under Grant No 2013CB921800the National Natural Science Foundation of China under Grant Nos 11227901,91021005,11104262,31470835,21233007,21303175,21322305,11374305 and 11274299the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant Nos XDB01030400 and 01020000
文摘In the past decades several theoretical Maxwell＇s demon models have been proposed to exhibit effects such as refrigerating, doing work at the cost of information, and some experiments have been carried out to realize these effects. We propose a model with a two-level demon, information represented by a sequence of bits, and two heat reservoirs. The reservoir that the demon is interacting with depends on the bit. When the temperature difference between the two heat reservoirs is large enough, the information can be erased. On the other hand, when the information is pure enough, heat transfer from one reservoir to the other can happen, resulting in the effect of refrigeration. Genuine examples of such a system are discussed.
文摘Photoplastic experiment were conducted with connecting rods of AX100 motorcycle engine during finish forging to investigate material plastic flow law of long -axis forgings with comples geometrie’s by observing
文摘The intensive competition of automotive market requ ir es shortening the product development circle and improving the product quality. Many of auto manufacturers in china have introduced some CAD/CAE/CAM systems in product development process, and have got some success. But the special and effi cient CAD system aimed at particular product is absent. This paper provides a CA D/CAE system that can realize the integration of CAD and CAE process for engine connecting rod development. The paper discusses some general methods in connecting rod design process, and s ums up structure characteristics of connecting rod. It introduces feature defini tion and feature classification facing connecting rod CAD/CAE system. Based on t he study of the feature technology and the feature of connecting rod, it creates the feature information model and feature database of engine connecting rod . In addition, it creates the parametric model of engine connection rod and real izes variable parametric design and variable structure design. With the help of Pro/Toolkit and Using C++ program to call the user ’s toolbox of Pro/ Engineer software system, the connecting rod CAD/CAE syst em can create connecting rod model automatically to meet the needs of different structure and different type of connecting rod. Based on Pro/Mechanica platform of PTC, the system can implements the Finite Ele ment Analysis and optimization of the connecting rod. Because using the same database in design and analysis, no data lost and no error occurs during da ta transforming. Using the connecting rod CAD/CAE system, the connecting rod can be meshed automatically and the FEA result can be achieved very fast and is very similar to the experiment. In a word, the connecting rod CAD/CAE system developed in this paper can optimiz e the product development process, realize the data share and concurrent enginee ring in the product design and analysis process, shorten the product develop ment circle, and improve the efficiency.
基金This work was supported by Shandong Province Natural Science Fund and Shandong Province Outstanding Young Scientists Fund Grant.
文摘A motorcycle connecting rod is one of the major moving parts affecting the engine performance. The traditional manufacturing process results in material waste and excessive machining. A new method of hot forging P/M has been proposed and studied experimentally. In order to achieve uniform density, the punch was divided into three parts to consolidate the loose powder. The multistage movement of the three parts of the punch, called synchronous compaction, results in the desired uniform density. Powder flow during consolidation was illustrated and the density distribution of the compacts was measured. A set of forging dies with flash was used to produce densification and deformation of the sintered compact. Then a set of flashless forging dies was designed to obtain the desired shape and dimensions of the connecting rod. The effects of forging temperature and initial compact density on densification were evaluated through hot forging experiments. Based on properties achieved, Fe-C-Cu-Mo was selected as the
文摘In order to obtain the desired mechanical properties of connecting bar after quenching and tempering,and reduce the cracking tendency and distortion,a program of controllable quenching was established.Furthermore,a computer-aided quenching (CAQ) system was developed.The applications show satisfactory results.
文摘To solve the optimal solution of some issues in applied science, studying of connecting conditions, constraint conditions and constraint equations is made. This paper cites an example in point in vibration mechanics and seeks the connecting conditions and constraint equations of high speed compound rotating system. This paper points out that the selection of the boundary conditions or connection conditions can effect on the optimal solution of the issue as soon as the object function is determined.
