Based on the analysis of the form characteristics and construction of the public space of oasis traditional settlements in Turpan,and from the analysis and summary of the types,elements,scales and functions of the pub...Based on the analysis of the form characteristics and construction of the public space of oasis traditional settlements in Turpan,and from the analysis and summary of the types,elements,scales and functions of the public space of the traditional settlements,this study put forward that the public space of the oasis villages can be divided into point space,line space and plane space,and the formation and evolution rules of the public space of oasis traditional settlements in Turpan were obtained.Explore the role of public space in the construction of traditional settlements’ overall space,so as to provide reference for the development and renewal of public space of the current similar oasis settlements.展开更多
The process of producing high viscosity polyester by transesterification polycondensation needs to adjust the operating conditions and equipment structure of pre-polycondensation kettle and final polycondensation kett...The process of producing high viscosity polyester by transesterification polycondensation needs to adjust the operating conditions and equipment structure of pre-polycondensation kettle and final polycondensation kettle to realize process intensification.In view of this,the fluid volume function method of computational fluid dynamics numerical simulation was used to investigate the film formation and surface renewal characteristics of horizontal polycondensation kettle under different operating conditions,including viscosity,rotating speed and liquid height.The results show that the viscosity and rotating speed were positively correlated with the film area and surface renewal in the pre-polycondensation stage.However,increasing the viscosity by several orders of magnitude in the final polycondensation kettle,the larger the film area and film thickness,but the overall surface renewal of the disk decreased.Therefore,a hexagonal hole disk is designed.By comparison,it is found that the film is more uniform,the surface update frequency is higher,and the power consumption can be reduced by more than 20%.展开更多
1 Introduction There is a long period of hot,arid climates in the Jurassic-Neogene,in the eastern of the Neo-Tethys where is been called Western Yunnan—Qiangtang tectonic belt(Zheng et al.,2010).Especially in the Pal...1 Introduction There is a long period of hot,arid climates in the Jurassic-Neogene,in the eastern of the Neo-Tethys where is been called Western Yunnan—Qiangtang tectonic belt(Zheng et al.,2010).Especially in the Paleogene,under the control of the planetary winds and the north subtropical high pressure belts,a ribbon arid,semi-arid展开更多
In this study,the test subjects included the aluminum alloys 2A14 and 5A06,as well as the welding wires ER2319 and ER5356,single laser welding,laser welding with filler wire,laser metal inert gas(laser-MIG)hybrid weld...In this study,the test subjects included the aluminum alloys 2A14 and 5A06,as well as the welding wires ER2319 and ER5356,single laser welding,laser welding with filler wire,laser metal inert gas(laser-MIG)hybrid welding and laser-MIG hybrid welding with filler wire were carried out respectively to research the influence of aluminum alloy base material and welding wire on weld forming charac-teristics.The results show that:under the same test conditions,the penetration of the base material 5A06 is greater than that of 2A14,the maximum is about 51.3%,and the penetration filling ER5356 is greater than that of ER2319,the maximum is about 32.2%;for 2A14 alu-minum alloy,the penetration is basically unchanged after filling with ER5356,and there is a relatively large decrease after filling ER2319,the maximum is about 21.2%;for 5A06 aluminum alloy,the penetration decreases after filling both kinds of welding wire,the penetration achieved with filler wire ER2319 is lower than that of ER5356.At the same time,through the process of laser absorption in different metal materials,it was found that the differences in material composition led to different laser absorption rates,resulting in different energy utiliza-tion,which is an important reason for the correlation between aluminum alloy materials and laser-MIG hybrid welding with filler wire.展开更多
Taking half-tube part with curvature as an example,the Impact Hydroforming(IHF)characteristics were studied by combining the actual forming experiment and numerical simulation.The IHF experiment showed that wrinkles a...Taking half-tube part with curvature as an example,the Impact Hydroforming(IHF)characteristics were studied by combining the actual forming experiment and numerical simulation.The IHF experiment showed that wrinkles appeared at the bottom of the part during single-step forming,but no wrinkles were observed during double-step forming.The thinning rate and deviation of the wall thickness of the part in each area were less than 20%and 2.7 mm,correspondingly,and the drawing depth of the part reached 45.8 mm.The effect of double-step forming was better than that of single-step forming,which was related to the IHF forming law.Besides,the characteristics of the IHF process were studied by numerical simulation.The results indicated that when double-step forming was utilized,there was almost no velocity field in the opposite direction of deformation after the bottom of the part contacted the die,and the existence of stress state at the bottom would restrain and eliminate the wrinkles.The inertia effect evolved with the driving pressure.Specially,the inertia effect can improve the flow of metal and reduce the deviation of the wall thickness of the part under double-step forming.展开更多
The multi-pass intermittent local loading process,which features a more flexible processing path,can further enhance the second material distribution during local loading,improve the formability of components,and redu...The multi-pass intermittent local loading process,which features a more flexible processing path,can further enhance the second material distribution during local loading,improve the formability of components,and reduce forming loads.However,the absence of compatible forming equipment makes it difficult to control the constraint in the unloaded zones during the forming process.This difficulty complicates coordination and control of deformation,particularly for asymmetric rib-web components.Additionally,the current implementation involves multi-fire heating,a long process flow,and high energy consumption,which limits the popularization and application of the local loading process.In this study,a new multi-pass local loading hydraulic forming apparatus that can quickly and reliably switch between heavy-load deformation and low-load constraint for different local loading sub-dies was developed.A 10-tonne laboratory prototype was developed,and the forming characteristics during the forming process as well as the response characteristics of the hydraulic system during the multi-pass intermittent local loading of rib-web component were investigated using numerical simulations and physical experiments.Results indicated that,compared to a whole loading process with the same initial geometry of billet,the total forming load(i.e.,the sum of loaded and restrained loads)is reduced by more than 40%with the local loading process,and by nearly 50%with multi-pass local loading.The multi-pass local loading process allows for more effective control of material flow compared to single-pass local loading,leading to improved cavity filling and reduced flow line disturbance.For a large-scale,complex titanium alloy bulkhead,the cavity filling problem was addressed by optimizing the multi-pass local loading path with an unequal thickness billet.The dynamic performance of the multi-pass local loading hydraulic system was found to be robust,with stable pressure transitions during motion and load switching for the sub-die(s).The dynamic characteristic of the hydraulic cylinder when switching from non-moving/unloaded state to a moving/loading state are consistent whether a load is present or not.However,the dynamic characteristics differ when switching from a moving/loading state to non-moving/unloaded state,showing opposite behavior.The developed hydraulic drive mechanism provides a way for implementation of multi-pass local loading without auxiliary operation and extra heating.The results of the study provide a foundation for the industrial production of large-scale,complex components with reduced force requirement and low-energy consumption.展开更多
Unlike conventional natural gas accumulations,unconventional ones have obvious particularity in reservoir forming conditions,enrichment mechanism,distribution modes,prediction method,and exploration technology.Analyzi...Unlike conventional natural gas accumulations,unconventional ones have obvious particularity in reservoir forming conditions,enrichment mechanism,distribution modes,prediction method,and exploration technology.Analyzing the reservoir forming process and main controlling factors of unconventional natural gas accumulations under the guide of the hydrocarbon accumulation system theory is of great significance for unconventional natural gas reservoir evaluation and prediction.Based on the reservoir forming mechanism and distribution mode,the unconventional natural gas accumulation systems are divided into six types,including shale gas,coalbed methane,tight carbonate gas,tight sandstone gas,water-soluble gas,and gas hydrate.According to the concept of“elementefunctionestructure”in the hydrocarbon accumulation system theory and the relationship of“gas source rockemigration systemeaccumulations distribution”,the unconventional gas accumulation system is divided into six“sourceelocation”types.The characteristics of the other five types of unconventional gas accumulation systems except gas hydrate are analyzed.The following results were obtained.(1)Shale gas,coalbed methane and tight carbonate gas belong to an intra-source type unconventional gas accumulation system,characterized by intense gas supply capacity,lack of either a transport system or secondary migration,integration of source,reservoir and caprock,in-situ accumulation,and so on.(2)Tight sandstone gas and water-soluble gas belong to a marginal unconventional gas accumulation system of source rock,characterized by diverse gas origin,near-source accumulation in adjacent layers of source rocks,internal migration within reservoirs,and so on.(3)Basin tectonic evolution,sedimentary environment and late tectonic events control the types of unconventional gas accumulation systems:The Paleozoic marine sediments in South China are conducive to the formation of shale gas and tight carbonate gas accumulation systems;The marineecontinental transitional facies deposits of Upper Paleozoic distributed in the South and North China are conducive to the development of coalbed methane,shale gas and tight sandstone gas accumulation systems;In the Middle and East China,MesozoiceCenozoic deep-water continental deposits are more conducive to the deep tight sandstone gas and shale gas accumulation systems,while shallow water continental basins are more conducive to the formation of coalbed methane,tight sandstone gas and shale gas accumulation systems.Water-soluble gas is widely found in the Cenozoic shallow-buried areas rich in organic matter or high-pressure reservoirs adjacent to gas source rocks.展开更多
In this article,we investigate the shift of Abbes and Saito’s ramification filtrations of the absolute Galois group of a complete discrete valuation field of positive characteristic under a purely inseparable extensi...In this article,we investigate the shift of Abbes and Saito’s ramification filtrations of the absolute Galois group of a complete discrete valuation field of positive characteristic under a purely inseparable extension.We also study a functoriality property for characteristic forms.展开更多
Over nearly a century from the early 20th century to the present,scholars have conducted in-depth explorations of the characteristics of literary forms of Yuan sanqu散曲,arriving at various summaries such as"secu...Over nearly a century from the early 20th century to the present,scholars have conducted in-depth explorations of the characteristics of literary forms of Yuan sanqu散曲,arriving at various summaries such as"secular,""humorous,""vivid,"and"tart."Various summaries indicate that our understanding of the characteristics of Yuan sanqu remains insufficient,necessitating further investigation to arrive at a more comprehensive summary that reflects the fundamental spirit of Yuan sanqu.The more comprehensive summary should be ye-yi野逸,representing a common living state,psychological state,and cultural spirit among literati in the Yuan Dynasty and is manifested in numerous aspects of Yuan literature and art.Historically,people have often recognized the ye-yi of Yuan literati primarily through Yuan paintings,but ye-yi is expressed even more fully in sanqu.The manifestations of yeyi in Yuan sanqu are diverse,including"unbridled and reckless spirit,""unrestrained and ingenious spirit with an unconfined mindset,""rustic and carefree spirit,""rural tranquility,""graceful wildness,""unconventional thoughts and fantasies,"and"vulgar and lowbrow works."展开更多
基金the National Natural Science Foundation of China(51768066)Funded Project of Doctoral Start-up Fund of Xinjiang University(620312355).
文摘Based on the analysis of the form characteristics and construction of the public space of oasis traditional settlements in Turpan,and from the analysis and summary of the types,elements,scales and functions of the public space of the traditional settlements,this study put forward that the public space of the oasis villages can be divided into point space,line space and plane space,and the formation and evolution rules of the public space of oasis traditional settlements in Turpan were obtained.Explore the role of public space in the construction of traditional settlements’ overall space,so as to provide reference for the development and renewal of public space of the current similar oasis settlements.
基金the financial support of the National Key Research and Development Program of China(2020YFA0710202,2018YFC0808805)。
文摘The process of producing high viscosity polyester by transesterification polycondensation needs to adjust the operating conditions and equipment structure of pre-polycondensation kettle and final polycondensation kettle to realize process intensification.In view of this,the fluid volume function method of computational fluid dynamics numerical simulation was used to investigate the film formation and surface renewal characteristics of horizontal polycondensation kettle under different operating conditions,including viscosity,rotating speed and liquid height.The results show that the viscosity and rotating speed were positively correlated with the film area and surface renewal in the pre-polycondensation stage.However,increasing the viscosity by several orders of magnitude in the final polycondensation kettle,the larger the film area and film thickness,but the overall surface renewal of the disk decreased.Therefore,a hexagonal hole disk is designed.By comparison,it is found that the film is more uniform,the surface update frequency is higher,and the power consumption can be reduced by more than 20%.
文摘1 Introduction There is a long period of hot,arid climates in the Jurassic-Neogene,in the eastern of the Neo-Tethys where is been called Western Yunnan—Qiangtang tectonic belt(Zheng et al.,2010).Especially in the Paleogene,under the control of the planetary winds and the north subtropical high pressure belts,a ribbon arid,semi-arid
基金supported by the Henan Science and Technology Plan Joint Fund Project(Key Project)(203ZP20230007).
文摘In this study,the test subjects included the aluminum alloys 2A14 and 5A06,as well as the welding wires ER2319 and ER5356,single laser welding,laser welding with filler wire,laser metal inert gas(laser-MIG)hybrid welding and laser-MIG hybrid welding with filler wire were carried out respectively to research the influence of aluminum alloy base material and welding wire on weld forming charac-teristics.The results show that:under the same test conditions,the penetration of the base material 5A06 is greater than that of 2A14,the maximum is about 51.3%,and the penetration filling ER5356 is greater than that of ER2319,the maximum is about 32.2%;for 2A14 alu-minum alloy,the penetration is basically unchanged after filling with ER5356,and there is a relatively large decrease after filling ER2319,the maximum is about 21.2%;for 5A06 aluminum alloy,the penetration decreases after filling both kinds of welding wire,the penetration achieved with filler wire ER2319 is lower than that of ER5356.At the same time,through the process of laser absorption in different metal materials,it was found that the differences in material composition led to different laser absorption rates,resulting in different energy utiliza-tion,which is an important reason for the correlation between aluminum alloy materials and laser-MIG hybrid welding with filler wire.
基金financially supported by the National Key R&D Program of China(No.2024YFE0108800/T24KITG014)the National Natural Science Foundation of China(No:52475411)the International Partnership Program of Chinese Academy of Sciences(No.172GJHZ2022096FN)。
文摘Taking half-tube part with curvature as an example,the Impact Hydroforming(IHF)characteristics were studied by combining the actual forming experiment and numerical simulation.The IHF experiment showed that wrinkles appeared at the bottom of the part during single-step forming,but no wrinkles were observed during double-step forming.The thinning rate and deviation of the wall thickness of the part in each area were less than 20%and 2.7 mm,correspondingly,and the drawing depth of the part reached 45.8 mm.The effect of double-step forming was better than that of single-step forming,which was related to the IHF forming law.Besides,the characteristics of the IHF process were studied by numerical simulation.The results indicated that when double-step forming was utilized,there was almost no velocity field in the opposite direction of deformation after the bottom of the part contacted the die,and the existence of stress state at the bottom would restrain and eliminate the wrinkles.The inertia effect evolved with the driving pressure.Specially,the inertia effect can improve the flow of metal and reduce the deviation of the wall thickness of the part under double-step forming.
基金the supports of the National Natural Science Foundation of China(Grant No.52375378)。
文摘The multi-pass intermittent local loading process,which features a more flexible processing path,can further enhance the second material distribution during local loading,improve the formability of components,and reduce forming loads.However,the absence of compatible forming equipment makes it difficult to control the constraint in the unloaded zones during the forming process.This difficulty complicates coordination and control of deformation,particularly for asymmetric rib-web components.Additionally,the current implementation involves multi-fire heating,a long process flow,and high energy consumption,which limits the popularization and application of the local loading process.In this study,a new multi-pass local loading hydraulic forming apparatus that can quickly and reliably switch between heavy-load deformation and low-load constraint for different local loading sub-dies was developed.A 10-tonne laboratory prototype was developed,and the forming characteristics during the forming process as well as the response characteristics of the hydraulic system during the multi-pass intermittent local loading of rib-web component were investigated using numerical simulations and physical experiments.Results indicated that,compared to a whole loading process with the same initial geometry of billet,the total forming load(i.e.,the sum of loaded and restrained loads)is reduced by more than 40%with the local loading process,and by nearly 50%with multi-pass local loading.The multi-pass local loading process allows for more effective control of material flow compared to single-pass local loading,leading to improved cavity filling and reduced flow line disturbance.For a large-scale,complex titanium alloy bulkhead,the cavity filling problem was addressed by optimizing the multi-pass local loading path with an unequal thickness billet.The dynamic performance of the multi-pass local loading hydraulic system was found to be robust,with stable pressure transitions during motion and load switching for the sub-die(s).The dynamic characteristic of the hydraulic cylinder when switching from non-moving/unloaded state to a moving/loading state are consistent whether a load is present or not.However,the dynamic characteristics differ when switching from a moving/loading state to non-moving/unloaded state,showing opposite behavior.The developed hydraulic drive mechanism provides a way for implementation of multi-pass local loading without auxiliary operation and extra heating.The results of the study provide a foundation for the industrial production of large-scale,complex components with reduced force requirement and low-energy consumption.
基金Project supported by the National Natural Science Foundation of China“Formation&Evolution and Enrichment Mechanism of Continental Shale Oil in Typical Basins in Central-West China”(No.42090020).
文摘Unlike conventional natural gas accumulations,unconventional ones have obvious particularity in reservoir forming conditions,enrichment mechanism,distribution modes,prediction method,and exploration technology.Analyzing the reservoir forming process and main controlling factors of unconventional natural gas accumulations under the guide of the hydrocarbon accumulation system theory is of great significance for unconventional natural gas reservoir evaluation and prediction.Based on the reservoir forming mechanism and distribution mode,the unconventional natural gas accumulation systems are divided into six types,including shale gas,coalbed methane,tight carbonate gas,tight sandstone gas,water-soluble gas,and gas hydrate.According to the concept of“elementefunctionestructure”in the hydrocarbon accumulation system theory and the relationship of“gas source rockemigration systemeaccumulations distribution”,the unconventional gas accumulation system is divided into six“sourceelocation”types.The characteristics of the other five types of unconventional gas accumulation systems except gas hydrate are analyzed.The following results were obtained.(1)Shale gas,coalbed methane and tight carbonate gas belong to an intra-source type unconventional gas accumulation system,characterized by intense gas supply capacity,lack of either a transport system or secondary migration,integration of source,reservoir and caprock,in-situ accumulation,and so on.(2)Tight sandstone gas and water-soluble gas belong to a marginal unconventional gas accumulation system of source rock,characterized by diverse gas origin,near-source accumulation in adjacent layers of source rocks,internal migration within reservoirs,and so on.(3)Basin tectonic evolution,sedimentary environment and late tectonic events control the types of unconventional gas accumulation systems:The Paleozoic marine sediments in South China are conducive to the formation of shale gas and tight carbonate gas accumulation systems;The marineecontinental transitional facies deposits of Upper Paleozoic distributed in the South and North China are conducive to the development of coalbed methane,shale gas and tight sandstone gas accumulation systems;In the Middle and East China,MesozoiceCenozoic deep-water continental deposits are more conducive to the deep tight sandstone gas and shale gas accumulation systems,while shallow water continental basins are more conducive to the formation of coalbed methane,tight sandstone gas and shale gas accumulation systems.Water-soluble gas is widely found in the Cenozoic shallow-buried areas rich in organic matter or high-pressure reservoirs adjacent to gas source rocks.
文摘In this article,we investigate the shift of Abbes and Saito’s ramification filtrations of the absolute Galois group of a complete discrete valuation field of positive characteristic under a purely inseparable extension.We also study a functoriality property for characteristic forms.
文摘Over nearly a century from the early 20th century to the present,scholars have conducted in-depth explorations of the characteristics of literary forms of Yuan sanqu散曲,arriving at various summaries such as"secular,""humorous,""vivid,"and"tart."Various summaries indicate that our understanding of the characteristics of Yuan sanqu remains insufficient,necessitating further investigation to arrive at a more comprehensive summary that reflects the fundamental spirit of Yuan sanqu.The more comprehensive summary should be ye-yi野逸,representing a common living state,psychological state,and cultural spirit among literati in the Yuan Dynasty and is manifested in numerous aspects of Yuan literature and art.Historically,people have often recognized the ye-yi of Yuan literati primarily through Yuan paintings,but ye-yi is expressed even more fully in sanqu.The manifestations of yeyi in Yuan sanqu are diverse,including"unbridled and reckless spirit,""unrestrained and ingenious spirit with an unconfined mindset,""rustic and carefree spirit,""rural tranquility,""graceful wildness,""unconventional thoughts and fantasies,"and"vulgar and lowbrow works."
