纯粹驾驶乐趣始终深植于宝马品牌的基因血脉之中。宝马Z4正是这一理念的完美化身——以敞篷跑车的极致魅力诠释无与伦比的驾驭激情。自2002年初代车型问世以来,这款双座敞篷跑车便凭借独树一帜的设计美学、纯粹至臻的驾驶体验和运动性...纯粹驾驶乐趣始终深植于宝马品牌的基因血脉之中。宝马Z4正是这一理念的完美化身——以敞篷跑车的极致魅力诠释无与伦比的驾驭激情。自2002年初代车型问世以来,这款双座敞篷跑车便凭借独树一帜的设计美学、纯粹至臻的驾驶体验和运动性能的完美平衡,持续征服全球车迷。即将推出的宝马Z4 Final Edition将为爱好者开启限时珍藏通道,提供订购这款特别版车型的专属机遇——它的限量身份和专属或将使它成为车坛的不朽经典。该版本配备了独特的配置元素,在外观和内饰方面均营造出个性化的亮点。同时,Final Edition也象征着这款标志性双座跑车迎来了其巅峰荣耀。宝马Z4的生产将于2026年3月正式结束。展开更多
In an aircraft final assembly line(AFAL),the rational scheduling of assembly workers to complete tasks in an orderly manner is crucial for enhancing production efficiency.This paper addresses the multi-skilled worker ...In an aircraft final assembly line(AFAL),the rational scheduling of assembly workers to complete tasks in an orderly manner is crucial for enhancing production efficiency.This paper addresses the multi-skilled worker scheduling problem in the AFAL,where the processing time of each task varies due to the assigned workers’skill levels,referred to as variable duration.The objective is to minimize the makespan,i.e.,the total time required for all workers to complete all tasks.A mixed integer linear programming model is formulated under complex constraints including assembly precedence relations,skill requirements,worker skill capabilities,and workspace capacities.To solve the model effectively,a multi-pass priority rule-based heuristic(MPRH)algorithm is proposed.This algorithm integrates 14 activity priority rules and nine worker priority rules with worker weights.Extensive experiments iteratively the best-performing priority rules,and the most effective rule subsets are integrated through a lightweight multi-pass mechanism to enhance its efficiency.The computational results demonstrate that the MPRH can find high-quality solutions effectively within very short central processing unit central processing unit(CPU)time compared to GUROBI.A case study based on real data obtained from an AFAL confirms the necessity and the feasibility of the approach in practical applications.Sensitivity analyses provide valuable insights to real production scenarios.展开更多
As a reliable additive manufacturing technology,the stereolithography(SLA)ceramic core necessitates a tailored sintering process to achieve optimal performance.This study explored the effects of final sintering temper...As a reliable additive manufacturing technology,the stereolithography(SLA)ceramic core necessitates a tailored sintering process to achieve optimal performance.This study explored the effects of final sintering temperatures(specifically 1,150,1,250,and 1,300°C)on the properties of SLA-fabricated SiO_(2)-based ceramic cores reinforced with nano-ZrO_(2)(at concentrations of 1.0wt.%,1.5wt.%,and 2.0wt.%).The results demonstrate that increasing the final sintering temperature and the incorporation of nano-ZrO_(2)enhance the viscous fiow of quartz glass,resulting in a higher sintering degree.As the final sintering temperature rises,the ceramic samples exhibit increased shrinkage rate,decreased apparent porosity,and increased bulk density.Higher final sintering temperatures also promote greater cristobalite precipitation,promoting an increase in the amount and precipitation rate of quartz during investment casting.The formation of a cristobalite and ZrSiO_4 network at elevated temperatures effectively inhibits the viscous flow of quartz glass,thereby significantly improving high-temperature flexural strength and creep resistance of ceramic cores.When the content of nano-ZrO_(2)is between 1.5wt.%and 2.0wt.%,the final sintering temperature of 1,250°C is the best choice.Under these conditions,the shrinkage rate along the Z direction ranges from 3.35%to 3.68%,the porosity lies between 25.57%and 26.03%,the bulk density varies from 1.612 to 1.645 g·cm^(-3),the room temperature fiexural strength is between 26.79 and 27.85 MPa,and the fiexural strength at high temperatures is within the range of 30.77 to 33.02 MPa.The defiection at high-temperatures is 3.37-5.31 mm,while the surface roughness of the upper surface is 3.26-4.79μm,and the surface roughness of the side surface is 4.97-5.79μm.These findings provide valuable guidance for optimizing the sintering processes of SLA ceramic cores,offering potential for industrial applications.展开更多
With the continuous adjustment of the energy structure,photovoltaic(PV)power generation projects are increasing,playing a crucial role in promoting the application of clean energy.However,the current audit of complete...With the continuous adjustment of the energy structure,photovoltaic(PV)power generation projects are increasing,playing a crucial role in promoting the application of clean energy.However,the current audit of completed final accounts for photovoltaic power generation projects faces many challenges,such as incomplete institutional processes,scattered archive management materials,inadequate digital intelligence systems,and insufficient analysis of final account amounts.Based on this,this article aims to deeply analyze these issues and propose targeted audit suggestions to standardize the construction and audit work of photovoltaic power generation projects and promote the sustainable and healthy development of the photovoltaic power generation business.展开更多
文摘纯粹驾驶乐趣始终深植于宝马品牌的基因血脉之中。宝马Z4正是这一理念的完美化身——以敞篷跑车的极致魅力诠释无与伦比的驾驭激情。自2002年初代车型问世以来,这款双座敞篷跑车便凭借独树一帜的设计美学、纯粹至臻的驾驶体验和运动性能的完美平衡,持续征服全球车迷。即将推出的宝马Z4 Final Edition将为爱好者开启限时珍藏通道,提供订购这款特别版车型的专属机遇——它的限量身份和专属或将使它成为车坛的不朽经典。该版本配备了独特的配置元素,在外观和内饰方面均营造出个性化的亮点。同时,Final Edition也象征着这款标志性双座跑车迎来了其巅峰荣耀。宝马Z4的生产将于2026年3月正式结束。
基金supported by the National Natural Science Foundation of China(52175475).
文摘In an aircraft final assembly line(AFAL),the rational scheduling of assembly workers to complete tasks in an orderly manner is crucial for enhancing production efficiency.This paper addresses the multi-skilled worker scheduling problem in the AFAL,where the processing time of each task varies due to the assigned workers’skill levels,referred to as variable duration.The objective is to minimize the makespan,i.e.,the total time required for all workers to complete all tasks.A mixed integer linear programming model is formulated under complex constraints including assembly precedence relations,skill requirements,worker skill capabilities,and workspace capacities.To solve the model effectively,a multi-pass priority rule-based heuristic(MPRH)algorithm is proposed.This algorithm integrates 14 activity priority rules and nine worker priority rules with worker weights.Extensive experiments iteratively the best-performing priority rules,and the most effective rule subsets are integrated through a lightweight multi-pass mechanism to enhance its efficiency.The computational results demonstrate that the MPRH can find high-quality solutions effectively within very short central processing unit central processing unit(CPU)time compared to GUROBI.A case study based on real data obtained from an AFAL confirms the necessity and the feasibility of the approach in practical applications.Sensitivity analyses provide valuable insights to real production scenarios.
基金supported by the Natural Science Foundation of Shanghai(No.23ZR1421500)the National Natural Science Foundation of China(Nos.52474412,52127807,52271035)+3 种基金the Shanghai Municipal Commission of Economy and Informatization(No.GYOJ2022-2-02)the United Innovation Program of Shanghai Commercial Aircraft Engine(No.AR966)the SPMI Project from Shanghai Academy of Spaceflight Technology(No.SPMI2022-06)the Ningbo International Science and Technology Cooperation Program(No.2023H004)。
文摘As a reliable additive manufacturing technology,the stereolithography(SLA)ceramic core necessitates a tailored sintering process to achieve optimal performance.This study explored the effects of final sintering temperatures(specifically 1,150,1,250,and 1,300°C)on the properties of SLA-fabricated SiO_(2)-based ceramic cores reinforced with nano-ZrO_(2)(at concentrations of 1.0wt.%,1.5wt.%,and 2.0wt.%).The results demonstrate that increasing the final sintering temperature and the incorporation of nano-ZrO_(2)enhance the viscous fiow of quartz glass,resulting in a higher sintering degree.As the final sintering temperature rises,the ceramic samples exhibit increased shrinkage rate,decreased apparent porosity,and increased bulk density.Higher final sintering temperatures also promote greater cristobalite precipitation,promoting an increase in the amount and precipitation rate of quartz during investment casting.The formation of a cristobalite and ZrSiO_4 network at elevated temperatures effectively inhibits the viscous flow of quartz glass,thereby significantly improving high-temperature flexural strength and creep resistance of ceramic cores.When the content of nano-ZrO_(2)is between 1.5wt.%and 2.0wt.%,the final sintering temperature of 1,250°C is the best choice.Under these conditions,the shrinkage rate along the Z direction ranges from 3.35%to 3.68%,the porosity lies between 25.57%and 26.03%,the bulk density varies from 1.612 to 1.645 g·cm^(-3),the room temperature fiexural strength is between 26.79 and 27.85 MPa,and the fiexural strength at high temperatures is within the range of 30.77 to 33.02 MPa.The defiection at high-temperatures is 3.37-5.31 mm,while the surface roughness of the upper surface is 3.26-4.79μm,and the surface roughness of the side surface is 4.97-5.79μm.These findings provide valuable guidance for optimizing the sintering processes of SLA ceramic cores,offering potential for industrial applications.
文摘With the continuous adjustment of the energy structure,photovoltaic(PV)power generation projects are increasing,playing a crucial role in promoting the application of clean energy.However,the current audit of completed final accounts for photovoltaic power generation projects faces many challenges,such as incomplete institutional processes,scattered archive management materials,inadequate digital intelligence systems,and insufficient analysis of final account amounts.Based on this,this article aims to deeply analyze these issues and propose targeted audit suggestions to standardize the construction and audit work of photovoltaic power generation projects and promote the sustainable and healthy development of the photovoltaic power generation business.
