To address the problems about the difficulty in accurate recognition of distribution features of gas flow center at blast furnace throat and determine the relationship between gas flow center distribution and gas util...To address the problems about the difficulty in accurate recognition of distribution features of gas flow center at blast furnace throat and determine the relationship between gas flow center distribution and gas utilization rate,a method for recognizing distribution features of blast furnace gas flow center was proposed based on infrared image processing,and distribution features of blast furnace gas flow center and corresponding gas utilization rates were categorized by using fuzzy C-means clustering and statistical methods.A concept of gas flow center offset was introduced.The results showed that,when the percentage of gas flow center without offset exceeded 85%,the average blast furnace gas utilization rate was as high as 41%;when the percentage of gas flow center without offset exceeded50%,the gas utilization rate was primarily the center gas utilization rate,and exhibited a positive correlation with no center offset degree;when the percentage of gas flow center without offset was below 50% but the sum of the percentage of gas flow center without offset and that of gas flow center with small offset exceeded 86%,the gas utilization rate depended on both the center and the edges,and was primarily the edge gas utilization rate.The method proposed was able to accurately and effectively recognize gas flow center distribution state and the relationship between it and gas utilization rate,providing evidence in favor of on-line blast furnace control.展开更多
Nitrogen-vacancy （NV） center in diamond is one of the most promising candidates to implement room temperature quantum computing. In this review, we briefly discuss the working principles and recent experimental prog...Nitrogen-vacancy （NV） center in diamond is one of the most promising candidates to implement room temperature quantum computing. In this review, we briefly discuss the working principles and recent experimental progresses of this spin qubit. These results focus on understanding and prolonging center spin coherence, steering and probing spin states with dedicated quantum control techniques, and exploiting the quantum nature of these multi-spin systems, such as superposition and entanglement, to demonstrate the superiority of quantum information processing. Those techniques also stimulate the fast development of NV-based quantum sensing, which is an interdisciplinary field with great potential applications.展开更多
A dvanced Metallic Materials Research and Processing Technology Center was found in December 1998. As a unit under The College of Mechanical Engineering, the Center is an expansion of the former Cast and Composite Mat...A dvanced Metallic Materials Research and Processing Technology Center was found in December 1998. As a unit under The College of Mechanical Engineering, the Center is an expansion of the former Cast and Composite Materials Research Group, which was found in the early eighties of last century. The Center is focusing in the basic and applied research, and development of advanced metallic materials and their processing technology. It also functions as an organization展开更多
Tsinghua-TOYO Research and Development Center of Magnesium and Aluminum Alloys Processing Technology was officially established between Tsinghua University and TOYO Machinery & Metal Co. on Feb. 26, 2002, which is...Tsinghua-TOYO Research and Development Center of Magnesium and Aluminum Alloys Processing Technology was officially established between Tsinghua University and TOYO Machinery & Metal Co. on Feb. 26, 2002, which is a non-independent legal research organization located in Department of Mechanical Engineering of Tsinghua University. The center was equipped with one set of 650t automatic magnesium and aluminum alloys diecasting machine and necessary accessories including the melting furnaces for magnesium alloys and aluminum alloys, an accurate magnesium pump to transfer the magnesium alloys to the shot sleeve of the die casting machine, a die temperature controller, and data logging systems for cavity pressure and die temperature distributions, etc. The center is aimed to the research and development of magnesium and aluminum die casting process and their related technologies, and the main research contents include:展开更多
Propelled by the rise of artificial intelligence,cloud services,and data center applications,next-generation,low-power,local-oscillator-less,digital signal processing(DSP)-free,and short-reach coherent optical communi...Propelled by the rise of artificial intelligence,cloud services,and data center applications,next-generation,low-power,local-oscillator-less,digital signal processing(DSP)-free,and short-reach coherent optical communication has evolved into an increasingly prominent area of research in recent years.Here,we demonstrate DSP-free coherent optical transmission by analog signal processing in frequency synchronous optical network(FSON)architecture,which supports polarization multiplexing and higher-order modulation formats.The FSON architecture that allows the numerous laser sources of optical transceivers within a data center can be quasi-synchronized by means of a tree-distributed homology architecture.In conjunction with our proposed pilot-tone assisted Costas loop for an analog coherent receiver,we achieve a record dual-polarization 224-Gb/s 16-QAM 5-km mismatch transmission with reset-free carrier phase recovery in the optical domain.Our proposed DSP-free analog coherent detection system based on the FSON makes it a promising solution for next-generation,low-power,and high-capacity coherent data center interconnects.展开更多
Single negatively charged nitrogen vacancy(NV-)centers in diamond have emerged as promising platforms for quantum information science,where long coherence times are essential for advancing quantum technologies.However...Single negatively charged nitrogen vacancy(NV-)centers in diamond have emerged as promising platforms for quantum information science,where long coherence times are essential for advancing quantum technologies.However,traditional fabrication methods often introduce lattice damage during the irradiation process used to create vacancies,significantly impairing the spin coherence properties of NV-centers.展开更多
The effective monitoring of tool wear status in the milling process of a five-axis machining center is important for improving product quality and efficiency,so this paper proposes a CNN convolutional neural network m...The effective monitoring of tool wear status in the milling process of a five-axis machining center is important for improving product quality and efficiency,so this paper proposes a CNN convolutional neural network model based on the optimization of PSO algorithm to monitor the tool wear status.Firstly,the cutting vibration signals and spindle current signals during the milling process of the five-axis machining center are collected using sensor technology,and the features related to the tool wear status are extracted in the time domain,frequency domain and time-frequency domain to form a feature sample matrix;secondly,the tool wear values corresponding to the above features are measured using an electron microscope and classified into three types:slight wear,normal wear and sharp wear to construct a target Finally,the tool wear sample data set is constructed by using multi-source information fusion technology and input to PSO-CNN model to complete the prediction of tool wear status.The results show that the proposed method can effectively predict the tool wear state with an accuracy of 98.27%;and compared with BP model,CNN model and SVM model,the accuracy indexes are improved by 9.48%,3.44%and 1.72%respectively,which indicates that the PSO-CNN model proposed in this paper has obvious advantages in the field of tool wear state identification.展开更多
Tool magazine is an important part of a processing center.Tool magazines have the advantage of reducing work parts turnover,handling,and storage time.In addition,some research shows that the use of tool magazine in ma...Tool magazine is an important part of a processing center.Tool magazines have the advantage of reducing work parts turnover,handling,and storage time.In addition,some research shows that the use of tool magazine in machine tools in the machining center can make the cutting time utilization rate of machine tools 3-4 times higher than that of ordinary machine tools,and has better machining consistency,thus improving processing accuracy and processing efficiency,shortening the production cycle.Therefore,the reliability,efficiency and accuracy of the tool magazine have a crucial impact on the stability of the machine tool.Therefore,the reliability analysis of CNC machine tool magazine is considerably important.In view of this problem,this paper puts forward that the reliability model of the tool magazine is established after the parameter estimation and hypothesis test,and then the maintainability model of the tool magazine is built,it ends with the fault analysis of the tool magazine.展开更多
This article explores, through a case study, measures of energy efficiency in data processing centers. An analysis of this case demonstrates how the design criteria could improve the rate of consumption in IT centers,...This article explores, through a case study, measures of energy efficiency in data processing centers. An analysis of this case demonstrates how the design criteria could improve the rate of consumption in IT centers, which is currently the second most contaminating industry on the planet, and is the responsible for 2% of CO2 emissions, surpassed only by the aeronautical industry. The present and future situation of IT center energy consumption and associated environmental effects is analyzed, and also looks at how state-of-the-art technology, correctly implemented, could ensure significant rationalization of data processing center energy consumption. The article will examine optimization techniques, specific problems and case studies.展开更多
To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC syst...To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle- tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP （rotation tool center point control） and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software struc- ture, the instructions with respect to the cutter＇s position and orientation can be directly carried out in the CNC system.展开更多
Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electro...Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electronic configuration in valley bottom exhibits inert activity,which seriously fetters the development of catalytic materials with great potentials.Herein,In d^(10)electronic configuration of In_(2)O_(3)was activated by phosphorus atoms replacing its lattice oxygen to regulate the collocation of the ascended In 5p-band(Inɛ5p)and descended O 2p-band(Oɛ2p)centers as efficient active sites for chemisorption to*OH and*H during forward HOS,respectively,along with a declined In 4d-band center(Inɛ4d)to inhibit its backward reaction.A stable STH efficiency of 2.23%under AM 1.5 G irradiation at 65°C has been obtained over the activated d^(10)electronic configuration with a lowered activation energy for H_(2)evolution,verified by femtosecond transient absorption spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations of dynamics.These findings devote to activating d^(10)electronic configuration for resolving the reaction energy barrier and dynamical bottleneck of forward HOS,which expands the exploration of high-efficiency catalytic materials.展开更多
In a context of growing efforts to develop sustainability strategies, energy-related issues occupy central stage in the built environment. Thus, the energy performance of housings has improved radically over the past ...In a context of growing efforts to develop sustainability strategies, energy-related issues occupy central stage in the built environment. Thus, the energy performance of housings has improved radically over the past decades. Yet other types of buildings, in particular commercial centers, haven’t received the same level of interest. As a result, there is a need for effective and practical measures to decrease their energy consumption, both for heating and electricity. The objective of the paper is to demonstrate that it is possible, through coherent strategies, to integrate energy issues and bioclimatic principles into the design process of commercial centers. It analyzes the exemplary case study of Marin Commercial Center (Switzerland). The interdisciplinary approach, based on integrated design strategies, aimed at increasing the energy efficiency while keeping the cost comparable to the market cost. The main design principles include natural ventilation, nighttime cooling with energy recovery and natural lighting, as well as optimization of mechanical systems. The results of the simulations show that Marin Center attains the best energy performance observed so far among Swiss commercial centers. It also meets the Swiss Minergie standard. The paper thus questions traditional design processes and outlines the need for interdisciplinary evaluation and monitoring approaches tailored for commercial centers. Even though most crucial decisions are taken during the early stages, all phases of the process require systematic optimization strategies, especially operating stages. Recommendations include legal measures, in particular in the fields of ventilation and air-conditioning, education, professional development and technology transfer, and financial incentives for the replacement of energy intensive installations.展开更多
This article proposes a framework, called BP-M* which includes: 1) a methodology to analyze, engineer, restructure and implement business processes, and 2) a process model that extends the process diagram with the spe...This article proposes a framework, called BP-M* which includes: 1) a methodology to analyze, engineer, restructure and implement business processes, and 2) a process model that extends the process diagram with the specification of resources that execute the process activities, allocation policies, schedules, times of activities, management of queues in input to the activities and workloads so that the same model can be simulated by a discrete event simulator. The BP-M* framework has been applied to a real case study, a public Contact Center which provides different typologies of answers to users’ requests. The simulation allows to study different system operating scenarios (“What-If” analysis) providing useful information for analysts to evaluate restructuring actions.展开更多
Additive manufacturing(AM)technology enables the creation of a wide variety of assemblies and complex shapes from three-dimensional model data in a bottom-up,layer-by-layer manner.Therefore,AM has revolutionized the m...Additive manufacturing(AM)technology enables the creation of a wide variety of assemblies and complex shapes from three-dimensional model data in a bottom-up,layer-by-layer manner.Therefore,AM has revolutionized the modern manufacturing industry,attracting increasing interest from both academic and industrial fields.The Rapid Manufacturing Center(RMC)of the School of Materials Science and Engineering at the Huazhong Univer-sity of Science and Technology(HUST),one of the earliest and most powerful AM research teams in China,has been engaged in AM research since 1991.Aiming to address the“stuck neck”problems of specific high-strength products for AM,the RMC has conducted full-chain research in the aspects of special materials,processes,equip-ment,and applications for AM.Moreover,it has formed a multi-disciplinary research team over the past three decades.Relevant research achievements in the AM field include winning five national awards,more than ten first prizes,and more than ten second prizes at the provincial and ministerial levels.The RMC was complimented as“the world’s most influential organization in the laser AM field in 2018”by Virtual and Physical Prototyping(an international authoritative magazine of AM).Moreover,their industrialization achievements were evaluated as“having affected countries such as Singapore,South Korea,and the United States”by an international author-itative Wohlers Report on AM.In this study,we first summarize the representative research achievements of the RMC in the AM field.These include the preparation and processing technology of high-performance polymeric,metallic,and ceramic materials for AM;advanced processing technology and software/equipment for AM;and typical AM-fabricated products and their applications.Further,we discuss the latest research achievements in cutting-edge 4D printing in terms of feedstock selection,printing processes,induction strategies,and potential ap-plications.Finally,we provide insights into the future directions of AM technology development:(ⅰ)Evolving from three-dimensional printing to multi-dimensional printing,(ⅱ)transitioning from plane slicing to curved surface slicing to woven slicing,(ⅲ)enhancing efficient formation from dot-line-sheet-volume printing,(ⅳ)shifting from single material to multi-materials AM,(ⅴ)advancing from the multiscale direction of macroscopic-mesoscopic-microscopic structures,(ⅵ)integrating material preparation with forming integration,(ⅶ)expanding from small batch to large batch.展开更多
基金Item Sponsored by National Natural Science Foundation of China(61263015)
文摘To address the problems about the difficulty in accurate recognition of distribution features of gas flow center at blast furnace throat and determine the relationship between gas flow center distribution and gas utilization rate,a method for recognizing distribution features of blast furnace gas flow center was proposed based on infrared image processing,and distribution features of blast furnace gas flow center and corresponding gas utilization rates were categorized by using fuzzy C-means clustering and statistical methods.A concept of gas flow center offset was introduced.The results showed that,when the percentage of gas flow center without offset exceeded 85%,the average blast furnace gas utilization rate was as high as 41%;when the percentage of gas flow center without offset exceeded50%,the gas utilization rate was primarily the center gas utilization rate,and exhibited a positive correlation with no center offset degree;when the percentage of gas flow center without offset was below 50% but the sum of the percentage of gas flow center without offset and that of gas flow center with small offset exceeded 86%,the gas utilization rate depended on both the center and the edges,and was primarily the edge gas utilization rate.The method proposed was able to accurately and effectively recognize gas flow center distribution state and the relationship between it and gas utilization rate,providing evidence in favor of on-line blast furnace control.
基金Project supported by the National Basic Research Program of China(Grant Nos.2014CB921402 and 2015CB921103)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB07010300)+1 种基金the National Natural Science Foundation of China(Grant No.11574386)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB0803)
文摘Nitrogen-vacancy （NV） center in diamond is one of the most promising candidates to implement room temperature quantum computing. In this review, we briefly discuss the working principles and recent experimental progresses of this spin qubit. These results focus on understanding and prolonging center spin coherence, steering and probing spin states with dedicated quantum control techniques, and exploiting the quantum nature of these multi-spin systems, such as superposition and entanglement, to demonstrate the superiority of quantum information processing. Those techniques also stimulate the fast development of NV-based quantum sensing, which is an interdisciplinary field with great potential applications.
文摘A dvanced Metallic Materials Research and Processing Technology Center was found in December 1998. As a unit under The College of Mechanical Engineering, the Center is an expansion of the former Cast and Composite Materials Research Group, which was found in the early eighties of last century. The Center is focusing in the basic and applied research, and development of advanced metallic materials and their processing technology. It also functions as an organization
文摘Tsinghua-TOYO Research and Development Center of Magnesium and Aluminum Alloys Processing Technology was officially established between Tsinghua University and TOYO Machinery & Metal Co. on Feb. 26, 2002, which is a non-independent legal research organization located in Department of Mechanical Engineering of Tsinghua University. The center was equipped with one set of 650t automatic magnesium and aluminum alloys diecasting machine and necessary accessories including the melting furnaces for magnesium alloys and aluminum alloys, an accurate magnesium pump to transfer the magnesium alloys to the shot sleeve of the die casting machine, a die temperature controller, and data logging systems for cavity pressure and die temperature distributions, etc. The center is aimed to the research and development of magnesium and aluminum die casting process and their related technologies, and the main research contents include:
基金supported by the National Natural Science Foundation of China(Grant Nos.62405250 and 62471404)the China Postdoctoral Science Foundation(Grant No.2024M762955)+1 种基金the Key Project of Westlake Institute for Optoelectronics(Grant No.2023GD003)the Optical Com-munication and Sensing Laboratory,School of Engineering,Westlake University.
文摘Propelled by the rise of artificial intelligence,cloud services,and data center applications,next-generation,low-power,local-oscillator-less,digital signal processing(DSP)-free,and short-reach coherent optical communication has evolved into an increasingly prominent area of research in recent years.Here,we demonstrate DSP-free coherent optical transmission by analog signal processing in frequency synchronous optical network(FSON)architecture,which supports polarization multiplexing and higher-order modulation formats.The FSON architecture that allows the numerous laser sources of optical transceivers within a data center can be quasi-synchronized by means of a tree-distributed homology architecture.In conjunction with our proposed pilot-tone assisted Costas loop for an analog coherent receiver,we achieve a record dual-polarization 224-Gb/s 16-QAM 5-km mismatch transmission with reset-free carrier phase recovery in the optical domain.Our proposed DSP-free analog coherent detection system based on the FSON makes it a promising solution for next-generation,low-power,and high-capacity coherent data center interconnects.
基金supported by the National Natural Science Foundation of China(Grant Nos.112374012 and 11974208)Shandong Provincial Natural Science Foundation(Grant Nos.ZR2023JQ001 and tsqn202211128)。
文摘Single negatively charged nitrogen vacancy(NV-)centers in diamond have emerged as promising platforms for quantum information science,where long coherence times are essential for advancing quantum technologies.However,traditional fabrication methods often introduce lattice damage during the irradiation process used to create vacancies,significantly impairing the spin coherence properties of NV-centers.
基金financed with the means of Basic Scientific Research Youth Program of Education Department of Liaoning Province,No.LJKQZ2021185Yingkou Enterprise and Doctor Innovation Program (QB-2021-05).
文摘The effective monitoring of tool wear status in the milling process of a five-axis machining center is important for improving product quality and efficiency,so this paper proposes a CNN convolutional neural network model based on the optimization of PSO algorithm to monitor the tool wear status.Firstly,the cutting vibration signals and spindle current signals during the milling process of the five-axis machining center are collected using sensor technology,and the features related to the tool wear status are extracted in the time domain,frequency domain and time-frequency domain to form a feature sample matrix;secondly,the tool wear values corresponding to the above features are measured using an electron microscope and classified into three types:slight wear,normal wear and sharp wear to construct a target Finally,the tool wear sample data set is constructed by using multi-source information fusion technology and input to PSO-CNN model to complete the prediction of tool wear status.The results show that the proposed method can effectively predict the tool wear state with an accuracy of 98.27%;and compared with BP model,CNN model and SVM model,the accuracy indexes are improved by 9.48%,3.44%and 1.72%respectively,which indicates that the PSO-CNN model proposed in this paper has obvious advantages in the field of tool wear state identification.
文摘Tool magazine is an important part of a processing center.Tool magazines have the advantage of reducing work parts turnover,handling,and storage time.In addition,some research shows that the use of tool magazine in machine tools in the machining center can make the cutting time utilization rate of machine tools 3-4 times higher than that of ordinary machine tools,and has better machining consistency,thus improving processing accuracy and processing efficiency,shortening the production cycle.Therefore,the reliability,efficiency and accuracy of the tool magazine have a crucial impact on the stability of the machine tool.Therefore,the reliability analysis of CNC machine tool magazine is considerably important.In view of this problem,this paper puts forward that the reliability model of the tool magazine is established after the parameter estimation and hypothesis test,and then the maintainability model of the tool magazine is built,it ends with the fault analysis of the tool magazine.
文摘This article explores, through a case study, measures of energy efficiency in data processing centers. An analysis of this case demonstrates how the design criteria could improve the rate of consumption in IT centers, which is currently the second most contaminating industry on the planet, and is the responsible for 2% of CO2 emissions, surpassed only by the aeronautical industry. The present and future situation of IT center energy consumption and associated environmental effects is analyzed, and also looks at how state-of-the-art technology, correctly implemented, could ensure significant rationalization of data processing center energy consumption. The article will examine optimization techniques, specific problems and case studies.
基金supported by the National Basic Research Program of China (No. 2011CB302400)the Important National Science & Technology Specific Projects (No. 2013ZX04007031).
文摘To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle- tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP （rotation tool center point control） and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software struc- ture, the instructions with respect to the cutter＇s position and orientation can be directly carried out in the CNC system.
文摘Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electronic configuration in valley bottom exhibits inert activity,which seriously fetters the development of catalytic materials with great potentials.Herein,In d^(10)electronic configuration of In_(2)O_(3)was activated by phosphorus atoms replacing its lattice oxygen to regulate the collocation of the ascended In 5p-band(Inɛ5p)and descended O 2p-band(Oɛ2p)centers as efficient active sites for chemisorption to*OH and*H during forward HOS,respectively,along with a declined In 4d-band center(Inɛ4d)to inhibit its backward reaction.A stable STH efficiency of 2.23%under AM 1.5 G irradiation at 65°C has been obtained over the activated d^(10)electronic configuration with a lowered activation energy for H_(2)evolution,verified by femtosecond transient absorption spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations of dynamics.These findings devote to activating d^(10)electronic configuration for resolving the reaction energy barrier and dynamical bottleneck of forward HOS,which expands the exploration of high-efficiency catalytic materials.
文摘In a context of growing efforts to develop sustainability strategies, energy-related issues occupy central stage in the built environment. Thus, the energy performance of housings has improved radically over the past decades. Yet other types of buildings, in particular commercial centers, haven’t received the same level of interest. As a result, there is a need for effective and practical measures to decrease their energy consumption, both for heating and electricity. The objective of the paper is to demonstrate that it is possible, through coherent strategies, to integrate energy issues and bioclimatic principles into the design process of commercial centers. It analyzes the exemplary case study of Marin Commercial Center (Switzerland). The interdisciplinary approach, based on integrated design strategies, aimed at increasing the energy efficiency while keeping the cost comparable to the market cost. The main design principles include natural ventilation, nighttime cooling with energy recovery and natural lighting, as well as optimization of mechanical systems. The results of the simulations show that Marin Center attains the best energy performance observed so far among Swiss commercial centers. It also meets the Swiss Minergie standard. The paper thus questions traditional design processes and outlines the need for interdisciplinary evaluation and monitoring approaches tailored for commercial centers. Even though most crucial decisions are taken during the early stages, all phases of the process require systematic optimization strategies, especially operating stages. Recommendations include legal measures, in particular in the fields of ventilation and air-conditioning, education, professional development and technology transfer, and financial incentives for the replacement of energy intensive installations.
文摘This article proposes a framework, called BP-M* which includes: 1) a methodology to analyze, engineer, restructure and implement business processes, and 2) a process model that extends the process diagram with the specification of resources that execute the process activities, allocation policies, schedules, times of activities, management of queues in input to the activities and workloads so that the same model can be simulated by a discrete event simulator. The BP-M* framework has been applied to a real case study, a public Contact Center which provides different typologies of answers to users’ requests. The simulation allows to study different system operating scenarios (“What-If” analysis) providing useful information for analysts to evaluate restructuring actions.
基金supported by National Natural Science Foundation of China(Grant Nos.52235008,U2037203,and U2341270)Key Research and Development Plan of Hubei Province(2022BAA030).
文摘Additive manufacturing(AM)technology enables the creation of a wide variety of assemblies and complex shapes from three-dimensional model data in a bottom-up,layer-by-layer manner.Therefore,AM has revolutionized the modern manufacturing industry,attracting increasing interest from both academic and industrial fields.The Rapid Manufacturing Center(RMC)of the School of Materials Science and Engineering at the Huazhong Univer-sity of Science and Technology(HUST),one of the earliest and most powerful AM research teams in China,has been engaged in AM research since 1991.Aiming to address the“stuck neck”problems of specific high-strength products for AM,the RMC has conducted full-chain research in the aspects of special materials,processes,equip-ment,and applications for AM.Moreover,it has formed a multi-disciplinary research team over the past three decades.Relevant research achievements in the AM field include winning five national awards,more than ten first prizes,and more than ten second prizes at the provincial and ministerial levels.The RMC was complimented as“the world’s most influential organization in the laser AM field in 2018”by Virtual and Physical Prototyping(an international authoritative magazine of AM).Moreover,their industrialization achievements were evaluated as“having affected countries such as Singapore,South Korea,and the United States”by an international author-itative Wohlers Report on AM.In this study,we first summarize the representative research achievements of the RMC in the AM field.These include the preparation and processing technology of high-performance polymeric,metallic,and ceramic materials for AM;advanced processing technology and software/equipment for AM;and typical AM-fabricated products and their applications.Further,we discuss the latest research achievements in cutting-edge 4D printing in terms of feedstock selection,printing processes,induction strategies,and potential ap-plications.Finally,we provide insights into the future directions of AM technology development:(ⅰ)Evolving from three-dimensional printing to multi-dimensional printing,(ⅱ)transitioning from plane slicing to curved surface slicing to woven slicing,(ⅲ)enhancing efficient formation from dot-line-sheet-volume printing,(ⅳ)shifting from single material to multi-materials AM,(ⅴ)advancing from the multiscale direction of macroscopic-mesoscopic-microscopic structures,(ⅵ)integrating material preparation with forming integration,(ⅶ)expanding from small batch to large batch.
