软件需求模型及其检测是软件需求工程中的重要工作.在分析现有需求建模方法和软件行为相关研究的基础上,对将软件行为概念引入需求模型进行了详细的阐述,提出一个面向软件行为的需求模型描述语言BDL(behavior description language),定...软件需求模型及其检测是软件需求工程中的重要工作.在分析现有需求建模方法和软件行为相关研究的基础上,对将软件行为概念引入需求模型进行了详细的阐述,提出一个面向软件行为的需求模型描述语言BDL(behavior description language),定义了它的语法、语义;讨论了CCS(calculus of communication system)与BDL的转换关系,构造了BDL到CCS的转换函数M〖-〗;给出了需求模型的系统一致性、系统安全性、行为可信性及行为非终止性等4种系统特性的时序逻辑描述;最后用模型验证工具CWB(Concurrency Work Bench)对BDL描述的具体实例进行验证分析.展开更多
The hot ductility of a Fe-0.3C-9Mn-2Al medium Mn steel was investigated using a Gleeble3800 thermo-mechanical simulator.Hot tensile tests were conducted at different temperatures(600-1300℃)under a constant strain rat...The hot ductility of a Fe-0.3C-9Mn-2Al medium Mn steel was investigated using a Gleeble3800 thermo-mechanical simulator.Hot tensile tests were conducted at different temperatures(600-1300℃)under a constant strain rate of 4×10^(−3)s^(−1).The fracture behavior and mechanism of hot ductility evolution were discussed.Results showed that the hot ductility decreased as the temperature was decreased from 1000℃.The reduction of area(RA)decreased rapidly in the specimens tested below 700℃,whereas that in the specimen tested at 650℃was lower than 65%.Mixed brittle-ductile fracture feature is reflected by the coexistence of cleavage step,intergranular facet,and dimple at the surface.The fracture belonged to ductile failure in the specimens tested between 720-1000℃.Large and deep dimples could delay crack propagation.The change in average width of the dimples was in positive proportion with the change in RA.The wide austenite-ferrite intercritical temperature range was crucial for the hot ductility of medium Mn steel.The formation of ferrite film on austenite grain boundaries led to strain concentration.Yield point elongation occurred at the austenite-ferrite intercritical temperature range during the hot tensile test.展开更多
The exploration of material failure behavior not only involves defining its limits and underlying mechanisms but also entails devising strategies for improvement and protection in extreme conditions.We've pioneere...The exploration of material failure behavior not only involves defining its limits and underlying mechanisms but also entails devising strategies for improvement and protection in extreme conditions.We've pioneered an advanced multi-scale,high-speed ascending thermal shock testing platform capable of inducing unprecedented heat shocks at rates surpassing 105℃/s.Through meticulous examination of the thermal shock responses of carbon nanotube(CNT)films,we've achieved remarkable breakthroughs.By employing an innovative macro-scale synchronous tightening and relaxing approach,we've attained a critical temperature differential in CNT films that exceeds an exceptional 2500℃—surpassing any previously reported metric for highperformance,thermal-shock-resistant materials.Notably,these samples have demonstrated exceptional resilience,retaining virtually unchanged strength even after enduring 10,000 thermal shock cycles at temperatures exceeding 1000℃.Furthermore,our research has revealed a novel thermal shock/fatigue failure mechanism that fundamentally diverges from conventional theories centered on thermal stress.展开更多
文摘软件需求模型及其检测是软件需求工程中的重要工作.在分析现有需求建模方法和软件行为相关研究的基础上,对将软件行为概念引入需求模型进行了详细的阐述,提出一个面向软件行为的需求模型描述语言BDL(behavior description language),定义了它的语法、语义;讨论了CCS(calculus of communication system)与BDL的转换关系,构造了BDL到CCS的转换函数M〖-〗;给出了需求模型的系统一致性、系统安全性、行为可信性及行为非终止性等4种系统特性的时序逻辑描述;最后用模型验证工具CWB(Concurrency Work Bench)对BDL描述的具体实例进行验证分析.
基金the Fundamental Research Funds for the Central Universities,China(Nos.FRF-TP-18-039A1,FRF-IDRY-19-013)the China Postdoctoral Science Foundation(No.2019M650482).
文摘The hot ductility of a Fe-0.3C-9Mn-2Al medium Mn steel was investigated using a Gleeble3800 thermo-mechanical simulator.Hot tensile tests were conducted at different temperatures(600-1300℃)under a constant strain rate of 4×10^(−3)s^(−1).The fracture behavior and mechanism of hot ductility evolution were discussed.Results showed that the hot ductility decreased as the temperature was decreased from 1000℃.The reduction of area(RA)decreased rapidly in the specimens tested below 700℃,whereas that in the specimen tested at 650℃was lower than 65%.Mixed brittle-ductile fracture feature is reflected by the coexistence of cleavage step,intergranular facet,and dimple at the surface.The fracture belonged to ductile failure in the specimens tested between 720-1000℃.Large and deep dimples could delay crack propagation.The change in average width of the dimples was in positive proportion with the change in RA.The wide austenite-ferrite intercritical temperature range was crucial for the hot ductility of medium Mn steel.The formation of ferrite film on austenite grain boundaries led to strain concentration.Yield point elongation occurred at the austenite-ferrite intercritical temperature range during the hot tensile test.
基金supported by the National Key Basic Research Program of China(No.2022YFA1205400)the National Natural Science Foundation of China(Nos.11832010,11890682,and 21721002)+3 种基金the Chinese Postdoctoral Science Foundation(Nos.E1I41IR1 and E2911IR1)Special Research Assistant Program of Chinese Academy of Sciences(No.E37551R1)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36010200)the Austrian-Chinese Cooperative Research and Development Projects(No.GJHZ2043).
文摘The exploration of material failure behavior not only involves defining its limits and underlying mechanisms but also entails devising strategies for improvement and protection in extreme conditions.We've pioneered an advanced multi-scale,high-speed ascending thermal shock testing platform capable of inducing unprecedented heat shocks at rates surpassing 105℃/s.Through meticulous examination of the thermal shock responses of carbon nanotube(CNT)films,we've achieved remarkable breakthroughs.By employing an innovative macro-scale synchronous tightening and relaxing approach,we've attained a critical temperature differential in CNT films that exceeds an exceptional 2500℃—surpassing any previously reported metric for highperformance,thermal-shock-resistant materials.Notably,these samples have demonstrated exceptional resilience,retaining virtually unchanged strength even after enduring 10,000 thermal shock cycles at temperatures exceeding 1000℃.Furthermore,our research has revealed a novel thermal shock/fatigue failure mechanism that fundamentally diverges from conventional theories centered on thermal stress.
