Vascular stents play an important role in the minimally invasive treatment of vascular diseases,such as vascular stenosis,vascular aneurysm,vascular dissection and vascular atherosclerotic plaque disease.Bare metal st...Vascular stents play an important role in the minimally invasive treatment of vascular diseases,such as vascular stenosis,vascular aneurysm,vascular dissection and vascular atherosclerotic plaque disease.Bare metal stents were initially fabricated;however,the incidence of complications such as thrombosis,inflammation,restenosis,vascular injury,displacement and endoleakage is still high after implantation.To overcome these complications,several strategies for designing functional vascular stents have been carried out.Drug-eluting stents,biodegradable stents and bionic stents were manufactured and investigated.This review aims to comprehensively analyze the vascular diseases suitable for stent implantation treatment,tissue reactions after implantation,the materials and manufacturing techniques used to fabricate vascular stents,the various application scenarios in which they could be used to treat vascular lesions and the development process of vascular stents.Future development trends of vascular stents are expected to prioritize their performance,biocompatibility,and clinical accessibility.The design of vascular stents may be transformed or improved to better fulfill the rehabilitation requirements of vascular disease patients.Finally,various application scenarios may be used to treat vascular or even nonvascular diseases via endovascular access.展开更多
Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,a...Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,and process optimization have significantly improved the efficiency,selectivity,and sustainability of these processes.This Account introduces the relevant research activities in the Research Center for Catalysis in Syngas Conversion and Fine Chemicals(DNL0805)of Dalian Institute of Chemical Physics(DICP),Chinese Academy of Sciences.The reactions of interests include FTS,heterogeneous hydroformylation of olefins,alcohol dehydration and oxidation,andα-olefin polymerization,with the emphasis on developing innovative catalysts and processes to address the challenges of traditional processes.Exemplified by the discovery of robust Co-Co_(2)C/AC for FTS and Rh_(1)/POPs-PPh_(3) for heterogeneous hydroformylation of olefins,it demonstrates how lab-scale fundamental understandings on the active sites of catalysts leads to pilot-plant scale-up and finally commercial technologies.Perspectives on the challenges and directions for future developments in these exciting fields are provided.展开更多
The development of chemical technologies,which involves a multistage process covering laboratory research,scale‐up to industrial deployment,and necessitates interdisciplinary collaboration,is often accompanied by sub...The development of chemical technologies,which involves a multistage process covering laboratory research,scale‐up to industrial deployment,and necessitates interdisciplinary collaboration,is often accompanied by substantial time and economic costs.To address these challenges,in this work,we report ChemELLM,a domain‐specific large language model(LLM)with 70 billion parameters for chemical engineering.ChemELLM demonstrates state‐of‐the‐art performance across critical tasks ranging from foundational understanding to professional problem‐solving.It outperforms mainstream LLMs(e.g.,O1‐Preview,GPT‐4o,and DeepSeek‐R1)on ChemEBench,the first multidimensional benchmark for chemical engineering,which encompasses 15 dimensions across 101 distinct essential tasks.To support robust model development,we curated ChemEData,a purpose‐built dataset containing 19 billion tokens for pre‐training and 1 billion tokens for fine‐tuning.This work establishes a new paradigm for artificial intelligence‐driven innovation,bridging the gap between laboratory‐scale innovation and industrial‐scale implementation,thus accelerating technological advancement in chemical engineering.ChemELLM is publicly available at https://chemindustry.iflytek.com/chat.展开更多
The rapid development of concepts and technologies for civil aircraft navigation systems has put forward higher requirements for agile iteration and integrated design verification in the research and development(R&...The rapid development of concepts and technologies for civil aircraft navigation systems has put forward higher requirements for agile iteration and integrated design verification in the research and development(R&D)process.Traditional document based system engineering(DBSE)methods have gradually become inadequate.Model based system engineering(MBSE)is fully based on user′s needs and is carried out from top to bottom,in line with the concept of forward design.It is gradually being applied in the development of civil aircraft systems.This article focuses on the civil aircraft radio navigation system and proposes a complete system engineering solution based on models,from system design and development to validation.Guided by the Arcadia methodology,with Capella modeling tool,Simulink simulation tool,and system validation tool,the complete R&D process from design and development to testing and validation was achieved through model construction,code generation,and testing validation.A radio navigation station selection optimization method based on machine learning was proposed,and results had good signal quality and persistence.The verification result of Beijing⁃Shanghai flight route shows MBSE method practiced in this article can ensure the feasibility of the entire process of radio navigation system development,as well as the rationality of tuning and positioning result.By automatically generating code to form a universal functional module,an optimization method that integrates different radio navigation station selection strategies is achieved,providing new ideas for the development and design of radio navigation systems.展开更多
An extra-large landslide occurred on June 19,2021,on the footwall slope of the Nanfen Open-pit Iron Mine in Liaoning Province,China,with a volume of approximately 1.2×107 m3.To elucidate the causative factors,dev...An extra-large landslide occurred on June 19,2021,on the footwall slope of the Nanfen Open-pit Iron Mine in Liaoning Province,China,with a volume of approximately 1.2×107 m3.To elucidate the causative factors,development process,and destructive mechanisms of this catastrophic landslide,comprehensive field tests,investigations,and laboratory experiments were conducted.Initially,the heavily weathered rock mass of the slope was intersected by faults and joint fissures,facilitating rainwater infiltration.Moreover,the landslide contained a substantial clay mineral with highly developed micro-cracks and micro-pores,exhibiting strong water-absorption properties.As moisture content increased,the rock mass underwent softening,resulting in reduced strength.Ultimately,continuous heavy rainfall infiltration amplified the slope's weight,diminishing the weak structural plane's strength,leading to fracture propagation,slip plane penetration,and extensive tensile-shear and uplift failure of the slope.The study highlights poor geological conditions as the decisive factor for this landslide,with continuous heavy rainfall as the triggering factor.Presently,adverse environmental factors persistently affect the landslide,and deformation and failure continue to escalate.Hence,it is imperative to urgently implement integrated measures encompassing slope reinforcement,monitoring,and early-warning to real-time monitor the landslide's deformation and deep mechanical evolution trends.展开更多
Streamers represent an important stage in the initiation of gap discharge. In this work, we used an eight-frame intensified charge-coupled device camera to capture the streamer development process when a lightning imp...Streamers represent an important stage in the initiation of gap discharge. In this work, we used an eight-frame intensified charge-coupled device camera to capture the streamer development process when a lightning impulse voltage of 95%–100% U50% was applied in a 3 m rod–plate gap and the streamer velocity was analyzed. Analysis of the observations shows that streamer velocity can be defined by three stages: rapid velocity decline(stage 1), rapid velocity rise(stage 2)and slow velocity decline(stage 3). The effects of electrode shape, applied voltage and gap breakdown or withstanding on streamer velocity were analyzed. The electrode with a larger radius of curvature will result in a higher initial velocity, and a higher voltage amplitude will cause the streamer to propagate faster at stage 3. Gap withstanding or breakdown has no obvious effect on streamer velocity. In addition, the experimental results are compared with previous results and the statistical characteristics of the primary streamer discharge are discussed.展开更多
Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process...Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process system"based on IPD(Integrated product development)in the organization.The development stage,process,activity and task are the logical framework elements of the system construction."Based on process decomposition,vertical stratification,horizontal segmentation,combination of special and common,process customized to tools,role and process integration,giving full consideration to the interface between supplier management and process modules"etc.are the concrete ideas.Moreover,formulate top⁃level system construction standards,implemented by process system management tool platform,so that the process system and development work can be effectively integrated to effectively guide the development work of airborne system suppliers,and meet the quality and airworthiness requirements of civil aircraft development.Through the development application of a certain type of flight control system,the process system and tool platform were verified and optimized in practice.展开更多
The development of women’s higher education in China can be divided into four stages:emergence(1908-1948);foundation(1949-1976);accelerating development(1977-2008);and the qualitative leap(2009-2020).This work consid...The development of women’s higher education in China can be divided into four stages:emergence(1908-1948);foundation(1949-1976);accelerating development(1977-2008);and the qualitative leap(2009-2020).This work considers the principal institutional mechanisms that contributed to this development.First,flexibly planned parenthood gradually promoted gender equality and openness in society facilitated by systematic“awards,grants,and loans”initiatives to support women’s higher education economically.Second,compulsory education ensured that left-out and migrant children had access to higher education.Third,effective connectivity across different education types bridged education gaps between those with different levels of education.Fourth,China made great efforts to invite and integrate international experiences that promoted the development of women’s higher education.Looking beyond these achievements,we also discuss the future trends of women’s higher education in China.展开更多
China is currently vigorously implementing the“energy conservation and emission reduction”and“dual carbon”strategies.As the most resource-advantaged light metal material in China,Magnesium(Mg)alloy is progressivel...China is currently vigorously implementing the“energy conservation and emission reduction”and“dual carbon”strategies.As the most resource-advantaged light metal material in China,Magnesium(Mg)alloy is progressively expanding its application in automobile,rail transportation,aerospace,medical,and electronic products.Chongqing University,Shanghai Jiaotong University,and Australian National University have conducted extensive research on the preparation,properties,and processes of Mg alloys.In the past 20 years,the proportion of Mg alloy in the automotive industry has gradually expanded,whereas currently the design and development of Mg alloy parts for automobiles has rarely been reported.Thus,the application models and typical parts cases of Mg alloy are summarized mainly from the four systems of the whole vehicle(body system,chassis system,powertrain system,interior,and exterior system).Subsequently,two actual original equipment manufacturers(OEM)cases are used to introduce the development logic of reliable die-cast Mg alloy,including forward design,formability analysis,process design analysis,structural redesign,manufacturing,and testing,aiming to share the methods,processes,and focus of attention of automotive OEMs for developing Mg alloy parts to enhance the confidence and motivation of applying Mg alloy in automotive field.Eventually,the multiple challenges faced by Mg alloy materials are sorted out and how to face these challenges are discussed.National policies and regulations,environmental protection and energy saving,and consumer demand will continue to promote the application of Mg.展开更多
Ambient air quality standards are the core strategic goal of ambient air quality management.Countries worldwide have given importance to research on the development of ambient air quality standards.To understand the h...Ambient air quality standards are the core strategic goal of ambient air quality management.Countries worldwide have given importance to research on the development of ambient air quality standards.To understand the history of the development of China’s ambient air quality standards,this study analyzed the background associated with all previous formulations and revisions of the standards,classification of functional areas,standard grading,pollutants,and evolution of the standard limits over the past 40 years.The results show that since the initial release of the“Ambient Air Quality Standard”by China in 1982,it has been supplemented once,revised twice,and modified twice.The first ambient air quality standard specified the standard limits of six pollutants commonly found in ambient air.With the development of ambient air quality management,the number of pollutants has increased to ten.Since the release of the“Ambient Air Quality Standards”in 2012,the ambient air quality in China has significantly improved.However,the proportion of cities meeting these standards is still low.At present,China is suitably positioned to make the standards associated with 24 hr SO2concentrations more stringent such that it meets the values defined in the World Health Organization(WHO)interim target-2 and the WHO air quality guideline(AQG).We further suggested that the SO2standard should be revised promptly.Simultaneously,regions with a relatively high proportion of cities meeting the standard are encouraged to introduce more stringent interim target limits in due course to manage the local ambient air quality.展开更多
In order to assure quality and control process in the development of the aircraft collaborative design software, a maturity assessment model is proposed. The requirements designing—house of quality is designed to eva...In order to assure quality and control process in the development of the aircraft collaborative design software, a maturity assessment model is proposed. The requirements designing—house of quality is designed to evaluate the maturity degree of the solution, and the evaluation results can help to manage and control the development process. Furthermore, a fuzzy evaluation method based on the minimum deviation is proposed to deal with the fuzzy information. The quantitative evaluation result of the maturity degree can be calculated by optimizing the semantic discount factor aim for the minimum deviation. Finally, this model is illustrated and analyzed by an example study of the aircraft collaborative design software.展开更多
This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on ...This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on the basic rheological theory are presented for more applications. Further consideration of the development and application of SSM technique is also proposed.展开更多
Urban Parks play an important role in the urban ecological environment. Based on the profound effect of ecological ideology on urban park design, we stud- ied the evolution course of ecological ideology and the charac...Urban Parks play an important role in the urban ecological environment. Based on the profound effect of ecological ideology on urban park design, we stud- ied the evolution course of ecological ideology and the characteristics of the ecological ideology at different stages in the United States, and emphatically introduced the influence of ecological ideology on the planning and design of New York Central Park, with the aim to summarize the inspiration for the urban park design in China.展开更多
This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of...This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The adsorption isotherms obtained in the linear region （or adsorption constant） are exploited as a model parameter required for the adsorption process simulation. The adsorption process model described by a set of partial differential equations （PDEs） is solved by using the conservation element and solution element method, which produces a fast and an accurate numerical solution to PDEs. The simulation results obtained from the adsorption constant estimated at the molecular level are in good agreement with the experimental results of the pulse response. The systematical multiscale simulation approach addressed in this study may be useful to accelerate the adsorption process development by reducing the number of experiments.展开更多
An improved and scalable process for substituted 3,8-diazabicyclo[3.2.1]octane was developed.N-Benzyl-2,5-dicarbethoxy-pyrrolidine 2 was reduced to N-benzyl-2.5-dihydroxymethylpyrrolidine 9 and subsequently debenzylat...An improved and scalable process for substituted 3,8-diazabicyclo[3.2.1]octane was developed.N-Benzyl-2,5-dicarbethoxy-pyrrolidine 2 was reduced to N-benzyl-2.5-dihydroxymethylpyrrolidine 9 and subsequently debenzylated to afford N-Boc-2,5- dihydroxymethylpyrrolidine 10.After mesylation of the diol 10 and cyclization with benzylamine,a diversity of scaffold,3,8- diazabicyclo[3.2.1]octane analogue 12 was obtained in a total yield of 42%in five steps.展开更多
The heterojunctions between metal and polymer have become the effective ways to produce the lighter,safer and more environmental friendly vehicles for the manufacturing fields of automotive and aerospace.The state-of-...The heterojunctions between metal and polymer have become the effective ways to produce the lighter,safer and more environmental friendly vehicles for the manufacturing fields of automotive and aerospace.The state-of-the-art frictionbased welding techniques are characterized by low peak temperature,severe plastic deformation,energy efficiency and nonpollution,which can simultaneously realize the mechanical and chemical bonding,improving mechanical performances.In this review,the current progress about friction-based welding techniques is summarized,containing technical development,welding tool design,microstructural characteristic,process optimization,surface modification and joining mechanism.The conclusions and prospects are presented,which focus on the practical implications for the manufacturing sectors and recommendations for further research and development.The purpose of this review is to elucidate the benefits of friction-based welding techniques so that these methods may be better exploited and industrialized.展开更多
For dividing-wall distillation columns(DWDCs) separating a heavy-component dominated and wide boiling-point ternary(HCDWBT) mixture, a significant amount of excessive heat exists inevitably in stripping the heavy-comp...For dividing-wall distillation columns(DWDCs) separating a heavy-component dominated and wide boiling-point ternary(HCDWBT) mixture, a significant amount of excessive heat exists inevitably in stripping the heavy-component from the intermediate-component and it can be employed to initiate the development of vapor recompression heat pump(VRHP) assisted DWDC(VRHP-DWDC). Despite dividing wall may locate in the top, middle, and bottom, the optimum VRHP-DWDC is found to involve uniformlytwo VRHP circles. While the first one serves to compress and transform the excessive heat resulted from the separation of the heavy-component from the intermediate-component, the second one to compress and transform the overhead vapor stream of the light-component pre-heated sequentially with the condensate from the first one and the bottom product stream of the heavy-component, both releasing the temperature-elevated latent heat to the pre-fractionator's or common stripping section. The processing of two HCDWBT mixtures of benzene/toluene/o-xylene and n-pentane/n-hexane/n-heptane are selected to assess the derived optimum topological configurations of the VRHP-DWDC and their optimality is confirmed through detailed comparisons with the DWDC and two VRHP-DWDCs involving only one VRHP circle. The proposed strategy helps to tap the full potential of the VRHP-DWDC with considerably alleviated complication in process development.展开更多
Superjunction technology is believed to reach the optimal specific on-resistance and breakdown voltage trade-off.It has become a mainstream technology in silicon high-voltage metal oxide semiconductor field effect tra...Superjunction technology is believed to reach the optimal specific on-resistance and breakdown voltage trade-off.It has become a mainstream technology in silicon high-voltage metal oxide semiconductor field effect transistor devices.Numerous efforts have been conducted to employ the same concept in silicon carbide devices.These works are summarized here.展开更多
Dispersed and peripheral spaces in the urban core are influenced both by the trend towards constant growth as well as social ways of life which are constantly evolving. Following a connotation, these two factors there...Dispersed and peripheral spaces in the urban core are influenced both by the trend towards constant growth as well as social ways of life which are constantly evolving. Following a connotation, these two factors therefore play a crucial role in defining the alternation of urban space--in particular, that of the centers. The main focus of this research article is on the methodology used in the survey and evaluation of ＂centralities＂ as well as their developments over the past four decades （1974-2014） in approaches to urban development that has been developed in Graz.~ The analysis has drawn on the four editions （＂evolution＂） of approaches to urban development as conceived by the city of Graz in order to examine their verbal characteristics in regard to centralities. At the same time, the analysis does not examine presentations of plans which exist in supplementary forms （e.g., explanatory reports and supplemented plans）--it restricts itself solely to the various plans set out in the STEKs.2 The highest degree of accuracy has been applied to the notion of ＂centralis＂ in approaches to urban development. The goal of the research project was to depict the modulation of the notion of ＂centrality＂ in the urban context as a space-forming dimension. Furthermore, it clearly shows the extent to which the notion of the ＂centre＂ （in the widest sense of the word） has become distanced from qualitative, spatial development and at the current time of urban development is experiencing a sort of Renaissance. In the field of ＂urban development＂, architectural references in the context of＂centrality＂ have scarcely been researched. This has led to the opening-up of a complex interdisciplinary research field. In order to make the complex architectural determinants of ＂centrality＂ more accessible to the participating disciplines, approaches to urban development have been explored in the form of a social and spatial analysis.展开更多
China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization an...China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization and agricultural modernization, but also exacerbated the situation of the urban–rural dual structure. Based on the review of current studies, we first used the analytic hierarchy process（AHP） method to evaluate the urban–rural development and transformation level by population transformation index, land transformation index, industrial transformation index and social transformation index between 1996 and 2012 around the Bohai Rim Region. Then, based on the results of each index, we used the exploratory spatial data analysis（ESDA） method to investigate the spatial autocorrelation of the change in the urban–rural development transformation index during the 16-year period using Global Moran＇s I index and Local Moran＇s I index. Finally, we investigated the mechanism of change of the urban–rural development transformation index at county level, summarizing five main factors：（1） the radiation from the surrounding big cities,（2） the acceleration of the urbanization process,（3） the upgrading of the industrial structure,（4） the publishing and implementation of a macro development strategy and regional policy, and（5） natural factors such as topology.展开更多
基金supported by Natural Science Foundation of China(No.31930067)Natural Science Foundation of Sichuan Province(No.23NSFSC5880)+2 种基金Chengdu Medical Research Project(No.2022004)Natural Science Foundation of Clinical Medical College and Affiliated Hospital of Chengdu University(No.Y202206)Postdoctoral Research and Development Fund of West China Hospital,Sichuan University(No.2023HXBH052).
文摘Vascular stents play an important role in the minimally invasive treatment of vascular diseases,such as vascular stenosis,vascular aneurysm,vascular dissection and vascular atherosclerotic plaque disease.Bare metal stents were initially fabricated;however,the incidence of complications such as thrombosis,inflammation,restenosis,vascular injury,displacement and endoleakage is still high after implantation.To overcome these complications,several strategies for designing functional vascular stents have been carried out.Drug-eluting stents,biodegradable stents and bionic stents were manufactured and investigated.This review aims to comprehensively analyze the vascular diseases suitable for stent implantation treatment,tissue reactions after implantation,the materials and manufacturing techniques used to fabricate vascular stents,the various application scenarios in which they could be used to treat vascular lesions and the development process of vascular stents.Future development trends of vascular stents are expected to prioritize their performance,biocompatibility,and clinical accessibility.The design of vascular stents may be transformed or improved to better fulfill the rehabilitation requirements of vascular disease patients.Finally,various application scenarios may be used to treat vascular or even nonvascular diseases via endovascular access.
文摘Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,and process optimization have significantly improved the efficiency,selectivity,and sustainability of these processes.This Account introduces the relevant research activities in the Research Center for Catalysis in Syngas Conversion and Fine Chemicals(DNL0805)of Dalian Institute of Chemical Physics(DICP),Chinese Academy of Sciences.The reactions of interests include FTS,heterogeneous hydroformylation of olefins,alcohol dehydration and oxidation,andα-olefin polymerization,with the emphasis on developing innovative catalysts and processes to address the challenges of traditional processes.Exemplified by the discovery of robust Co-Co_(2)C/AC for FTS and Rh_(1)/POPs-PPh_(3) for heterogeneous hydroformylation of olefins,it demonstrates how lab-scale fundamental understandings on the active sites of catalysts leads to pilot-plant scale-up and finally commercial technologies.Perspectives on the challenges and directions for future developments in these exciting fields are provided.
文摘The development of chemical technologies,which involves a multistage process covering laboratory research,scale‐up to industrial deployment,and necessitates interdisciplinary collaboration,is often accompanied by substantial time and economic costs.To address these challenges,in this work,we report ChemELLM,a domain‐specific large language model(LLM)with 70 billion parameters for chemical engineering.ChemELLM demonstrates state‐of‐the‐art performance across critical tasks ranging from foundational understanding to professional problem‐solving.It outperforms mainstream LLMs(e.g.,O1‐Preview,GPT‐4o,and DeepSeek‐R1)on ChemEBench,the first multidimensional benchmark for chemical engineering,which encompasses 15 dimensions across 101 distinct essential tasks.To support robust model development,we curated ChemEData,a purpose‐built dataset containing 19 billion tokens for pre‐training and 1 billion tokens for fine‐tuning.This work establishes a new paradigm for artificial intelligence‐driven innovation,bridging the gap between laboratory‐scale innovation and industrial‐scale implementation,thus accelerating technological advancement in chemical engineering.ChemELLM is publicly available at https://chemindustry.iflytek.com/chat.
文摘The rapid development of concepts and technologies for civil aircraft navigation systems has put forward higher requirements for agile iteration and integrated design verification in the research and development(R&D)process.Traditional document based system engineering(DBSE)methods have gradually become inadequate.Model based system engineering(MBSE)is fully based on user′s needs and is carried out from top to bottom,in line with the concept of forward design.It is gradually being applied in the development of civil aircraft systems.This article focuses on the civil aircraft radio navigation system and proposes a complete system engineering solution based on models,from system design and development to validation.Guided by the Arcadia methodology,with Capella modeling tool,Simulink simulation tool,and system validation tool,the complete R&D process from design and development to testing and validation was achieved through model construction,code generation,and testing validation.A radio navigation station selection optimization method based on machine learning was proposed,and results had good signal quality and persistence.The verification result of Beijing⁃Shanghai flight route shows MBSE method practiced in this article can ensure the feasibility of the entire process of radio navigation system development,as well as the rationality of tuning and positioning result.By automatically generating code to form a universal functional module,an optimization method that integrates different radio navigation station selection strategies is achieved,providing new ideas for the development and design of radio navigation systems.
基金supported by the National Natural Science Foundation of China(Grant No.52074295)the State Key Laboratory for GeoMechanics and Deep Underground Engineering,China University of Mining&Technology,Beijing(Grant No.SKLGDUEK202217).
文摘An extra-large landslide occurred on June 19,2021,on the footwall slope of the Nanfen Open-pit Iron Mine in Liaoning Province,China,with a volume of approximately 1.2×107 m3.To elucidate the causative factors,development process,and destructive mechanisms of this catastrophic landslide,comprehensive field tests,investigations,and laboratory experiments were conducted.Initially,the heavily weathered rock mass of the slope was intersected by faults and joint fissures,facilitating rainwater infiltration.Moreover,the landslide contained a substantial clay mineral with highly developed micro-cracks and micro-pores,exhibiting strong water-absorption properties.As moisture content increased,the rock mass underwent softening,resulting in reduced strength.Ultimately,continuous heavy rainfall infiltration amplified the slope's weight,diminishing the weak structural plane's strength,leading to fracture propagation,slip plane penetration,and extensive tensile-shear and uplift failure of the slope.The study highlights poor geological conditions as the decisive factor for this landslide,with continuous heavy rainfall as the triggering factor.Presently,adverse environmental factors persistently affect the landslide,and deformation and failure continue to escalate.Hence,it is imperative to urgently implement integrated measures encompassing slope reinforcement,monitoring,and early-warning to real-time monitor the landslide's deformation and deep mechanical evolution trends.
基金supported by the Beijing Science Fund for Distinguished Young Scholars(No.JQ22009)National Natural Science Foundation of China(No.51977198)。
文摘Streamers represent an important stage in the initiation of gap discharge. In this work, we used an eight-frame intensified charge-coupled device camera to capture the streamer development process when a lightning impulse voltage of 95%–100% U50% was applied in a 3 m rod–plate gap and the streamer velocity was analyzed. Analysis of the observations shows that streamer velocity can be defined by three stages: rapid velocity decline(stage 1), rapid velocity rise(stage 2)and slow velocity decline(stage 3). The effects of electrode shape, applied voltage and gap breakdown or withstanding on streamer velocity were analyzed. The electrode with a larger radius of curvature will result in a higher initial velocity, and a higher voltage amplitude will cause the streamer to propagate faster at stage 3. Gap withstanding or breakdown has no obvious effect on streamer velocity. In addition, the experimental results are compared with previous results and the statistical characteristics of the primary streamer discharge are discussed.
文摘Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process system"based on IPD(Integrated product development)in the organization.The development stage,process,activity and task are the logical framework elements of the system construction."Based on process decomposition,vertical stratification,horizontal segmentation,combination of special and common,process customized to tools,role and process integration,giving full consideration to the interface between supplier management and process modules"etc.are the concrete ideas.Moreover,formulate top⁃level system construction standards,implemented by process system management tool platform,so that the process system and development work can be effectively integrated to effectively guide the development work of airborne system suppliers,and meet the quality and airworthiness requirements of civil aircraft development.Through the development application of a certain type of flight control system,the process system and tool platform were verified and optimized in practice.
基金“Promoting research by writing”:Exploring the code of writing,supported by the Special Fund for basic scientific research of the Central University,Northwestern Polytechnical University(project no.KCJS23WT25).“Research on the construction of the linking-up curriculum system:Taking the industry characteristic research university as an example”was established by the Ministry of Education’s Youth Fund for Humanities and Social Sciences,the Department of Social Sciences of the Ministry of Education(project no.23YJC880099).
文摘The development of women’s higher education in China can be divided into four stages:emergence(1908-1948);foundation(1949-1976);accelerating development(1977-2008);and the qualitative leap(2009-2020).This work considers the principal institutional mechanisms that contributed to this development.First,flexibly planned parenthood gradually promoted gender equality and openness in society facilitated by systematic“awards,grants,and loans”initiatives to support women’s higher education economically.Second,compulsory education ensured that left-out and migrant children had access to higher education.Third,effective connectivity across different education types bridged education gaps between those with different levels of education.Fourth,China made great efforts to invite and integrate international experiences that promoted the development of women’s higher education.Looking beyond these achievements,we also discuss the future trends of women’s higher education in China.
基金supported partly by the Fundamental Research Funds for Central Universities(No.06500203 and No.00007735).
文摘China is currently vigorously implementing the“energy conservation and emission reduction”and“dual carbon”strategies.As the most resource-advantaged light metal material in China,Magnesium(Mg)alloy is progressively expanding its application in automobile,rail transportation,aerospace,medical,and electronic products.Chongqing University,Shanghai Jiaotong University,and Australian National University have conducted extensive research on the preparation,properties,and processes of Mg alloys.In the past 20 years,the proportion of Mg alloy in the automotive industry has gradually expanded,whereas currently the design and development of Mg alloy parts for automobiles has rarely been reported.Thus,the application models and typical parts cases of Mg alloy are summarized mainly from the four systems of the whole vehicle(body system,chassis system,powertrain system,interior,and exterior system).Subsequently,two actual original equipment manufacturers(OEM)cases are used to introduce the development logic of reliable die-cast Mg alloy,including forward design,formability analysis,process design analysis,structural redesign,manufacturing,and testing,aiming to share the methods,processes,and focus of attention of automotive OEMs for developing Mg alloy parts to enhance the confidence and motivation of applying Mg alloy in automotive field.Eventually,the multiple challenges faced by Mg alloy materials are sorted out and how to face these challenges are discussed.National policies and regulations,environmental protection and energy saving,and consumer demand will continue to promote the application of Mg.
基金supported by the National Key Research and Development Program of China(Nos.2019YFC0214800,2020YFC1806303 and 2016YFC0208100)the Fundamental Research Funds for the Central Public-interest Scientific Institution(No.2021YSKY-06)。
文摘Ambient air quality standards are the core strategic goal of ambient air quality management.Countries worldwide have given importance to research on the development of ambient air quality standards.To understand the history of the development of China’s ambient air quality standards,this study analyzed the background associated with all previous formulations and revisions of the standards,classification of functional areas,standard grading,pollutants,and evolution of the standard limits over the past 40 years.The results show that since the initial release of the“Ambient Air Quality Standard”by China in 1982,it has been supplemented once,revised twice,and modified twice.The first ambient air quality standard specified the standard limits of six pollutants commonly found in ambient air.With the development of ambient air quality management,the number of pollutants has increased to ten.Since the release of the“Ambient Air Quality Standards”in 2012,the ambient air quality in China has significantly improved.However,the proportion of cities meeting these standards is still low.At present,China is suitably positioned to make the standards associated with 24 hr SO2concentrations more stringent such that it meets the values defined in the World Health Organization(WHO)interim target-2 and the WHO air quality guideline(AQG).We further suggested that the SO2standard should be revised promptly.Simultaneously,regions with a relatively high proportion of cities meeting the standard are encouraged to introduce more stringent interim target limits in due course to manage the local ambient air quality.
基金supported by the National Natural Science Foundation for Youth of China(61802174)the Natural Science Foundation for Youth of Jiangsu Province(BK20181016)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(18KJB520019)the Scientific Research Foundation of Nanjing Institute of Technology of China(YKJ201614)
文摘In order to assure quality and control process in the development of the aircraft collaborative design software, a maturity assessment model is proposed. The requirements designing—house of quality is designed to evaluate the maturity degree of the solution, and the evaluation results can help to manage and control the development process. Furthermore, a fuzzy evaluation method based on the minimum deviation is proposed to deal with the fuzzy information. The quantitative evaluation result of the maturity degree can be calculated by optimizing the semantic discount factor aim for the minimum deviation. Finally, this model is illustrated and analyzed by an example study of the aircraft collaborative design software.
基金the National Natural Science foundation of China! (59995440)
文摘This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on the basic rheological theory are presented for more applications. Further consideration of the development and application of SSM technique is also proposed.
文摘Urban Parks play an important role in the urban ecological environment. Based on the profound effect of ecological ideology on urban park design, we stud- ied the evolution course of ecological ideology and the characteristics of the ecological ideology at different stages in the United States, and emphatically introduced the influence of ecological ideology on the planning and design of New York Central Park, with the aim to summarize the inspiration for the urban park design in China.
基金the Basic Research Program of the Korea Science & Engineering Foundation (KoSEF, No. R01-2006-000-10786-0).
文摘This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The adsorption isotherms obtained in the linear region （or adsorption constant） are exploited as a model parameter required for the adsorption process simulation. The adsorption process model described by a set of partial differential equations （PDEs） is solved by using the conservation element and solution element method, which produces a fast and an accurate numerical solution to PDEs. The simulation results obtained from the adsorption constant estimated at the molecular level are in good agreement with the experimental results of the pulse response. The systematical multiscale simulation approach addressed in this study may be useful to accelerate the adsorption process development by reducing the number of experiments.
基金supported by the program of research fund for returning scholars of Ministry of Education of China(No.200812053)
文摘An improved and scalable process for substituted 3,8-diazabicyclo[3.2.1]octane was developed.N-Benzyl-2,5-dicarbethoxy-pyrrolidine 2 was reduced to N-benzyl-2.5-dihydroxymethylpyrrolidine 9 and subsequently debenzylated to afford N-Boc-2,5- dihydroxymethylpyrrolidine 10.After mesylation of the diol 10 and cyclization with benzylamine,a diversity of scaffold,3,8- diazabicyclo[3.2.1]octane analogue 12 was obtained in a total yield of 42%in five steps.
基金supported by the National Natural Science Foundation of China(Nos.52205350 and 52175301)the China Postdoctoral Science Foundation(Nos.2021M690820 and 2021T140151)and the Heilongjiang Postdoctoral Fund(LBH-Z20055).
文摘The heterojunctions between metal and polymer have become the effective ways to produce the lighter,safer and more environmental friendly vehicles for the manufacturing fields of automotive and aerospace.The state-of-the-art frictionbased welding techniques are characterized by low peak temperature,severe plastic deformation,energy efficiency and nonpollution,which can simultaneously realize the mechanical and chemical bonding,improving mechanical performances.In this review,the current progress about friction-based welding techniques is summarized,containing technical development,welding tool design,microstructural characteristic,process optimization,surface modification and joining mechanism.The conclusions and prospects are presented,which focus on the practical implications for the manufacturing sectors and recommendations for further research and development.The purpose of this review is to elucidate the benefits of friction-based welding techniques so that these methods may be better exploited and industrialized.
基金The financial support from National Natural Science Foundation of China (21878011)。
文摘For dividing-wall distillation columns(DWDCs) separating a heavy-component dominated and wide boiling-point ternary(HCDWBT) mixture, a significant amount of excessive heat exists inevitably in stripping the heavy-component from the intermediate-component and it can be employed to initiate the development of vapor recompression heat pump(VRHP) assisted DWDC(VRHP-DWDC). Despite dividing wall may locate in the top, middle, and bottom, the optimum VRHP-DWDC is found to involve uniformlytwo VRHP circles. While the first one serves to compress and transform the excessive heat resulted from the separation of the heavy-component from the intermediate-component, the second one to compress and transform the overhead vapor stream of the light-component pre-heated sequentially with the condensate from the first one and the bottom product stream of the heavy-component, both releasing the temperature-elevated latent heat to the pre-fractionator's or common stripping section. The processing of two HCDWBT mixtures of benzene/toluene/o-xylene and n-pentane/n-hexane/n-heptane are selected to assess the derived optimum topological configurations of the VRHP-DWDC and their optimality is confirmed through detailed comparisons with the DWDC and two VRHP-DWDCs involving only one VRHP circle. The proposed strategy helps to tap the full potential of the VRHP-DWDC with considerably alleviated complication in process development.
基金supported by the National Key Research and Development Program(No.2016YFB0400500)the Key Research and Development Projects in Guangdong Province(No.2019B010144001)。
文摘Superjunction technology is believed to reach the optimal specific on-resistance and breakdown voltage trade-off.It has become a mainstream technology in silicon high-voltage metal oxide semiconductor field effect transistor devices.Numerous efforts have been conducted to employ the same concept in silicon carbide devices.These works are summarized here.
文摘Dispersed and peripheral spaces in the urban core are influenced both by the trend towards constant growth as well as social ways of life which are constantly evolving. Following a connotation, these two factors therefore play a crucial role in defining the alternation of urban space--in particular, that of the centers. The main focus of this research article is on the methodology used in the survey and evaluation of ＂centralities＂ as well as their developments over the past four decades （1974-2014） in approaches to urban development that has been developed in Graz.~ The analysis has drawn on the four editions （＂evolution＂） of approaches to urban development as conceived by the city of Graz in order to examine their verbal characteristics in regard to centralities. At the same time, the analysis does not examine presentations of plans which exist in supplementary forms （e.g., explanatory reports and supplemented plans）--it restricts itself solely to the various plans set out in the STEKs.2 The highest degree of accuracy has been applied to the notion of ＂centralis＂ in approaches to urban development. The goal of the research project was to depict the modulation of the notion of ＂centrality＂ in the urban context as a space-forming dimension. Furthermore, it clearly shows the extent to which the notion of the ＂centre＂ （in the widest sense of the word） has become distanced from qualitative, spatial development and at the current time of urban development is experiencing a sort of Renaissance. In the field of ＂urban development＂, architectural references in the context of＂centrality＂ have scarcely been researched. This has led to the opening-up of a complex interdisciplinary research field. In order to make the complex architectural determinants of ＂centrality＂ more accessible to the participating disciplines, approaches to urban development have been explored in the form of a social and spatial analysis.
基金National Natural Science Foundation of China,No.41130748No.41471143
文摘China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization and agricultural modernization, but also exacerbated the situation of the urban–rural dual structure. Based on the review of current studies, we first used the analytic hierarchy process（AHP） method to evaluate the urban–rural development and transformation level by population transformation index, land transformation index, industrial transformation index and social transformation index between 1996 and 2012 around the Bohai Rim Region. Then, based on the results of each index, we used the exploratory spatial data analysis（ESDA） method to investigate the spatial autocorrelation of the change in the urban–rural development transformation index during the 16-year period using Global Moran＇s I index and Local Moran＇s I index. Finally, we investigated the mechanism of change of the urban–rural development transformation index at county level, summarizing five main factors：（1） the radiation from the surrounding big cities,（2） the acceleration of the urbanization process,（3） the upgrading of the industrial structure,（4） the publishing and implementation of a macro development strategy and regional policy, and（5） natural factors such as topology.
