Review on the plastic instability of medium -Mn steels for identifying the formation mechanisms of Lüders and Portevin -Le Chatelier bands

Plastic instability,including both the discontinuous yielding and stress serrations,has been frequently observed during the tensile deformation of medium-Mn steels(MMnS)and has been intensively studied in recent years.Unfortunately,research results are controversial,and no consensus has been achieved regarding the topic.Here,we first summarize all the possible factors that affect the yielding and flow stress serrations in MMnS,including the morphology and stability of austenite,the feature of the phase interface,and the deformation parameters.Then,we propose a universal mechanism to explain the conflicting experimental results.We conclude that the discontinuous yielding can be attributed to the lack of mobile dislocation before deformation and the rapid dislocation multiplication at the beginning of plastic deformation.Meanwhile,the results show that the stress serrations are formed due to the pinning and depinning between dislocations and interstitial atoms in austenite.Strain-induced martensitic transformation,influenced by the mechanical stability of austenite grain and deformation parameters,should not be the intrinsic cause of plastic instability.However,it can intensify or weaken the discontinuous yielding and the stress serrations by affecting the mobility and density of dislocations,as well as the interaction between the interstitial atoms and dislocations in austenite grains.

Intelligent Vehicle Auxiliary Handling System Based on the Internet of Things Technology

This paper proposes an intelligent vehicle auxiliary handling system based on Internet of Things(IoT)technology,featuring an innovative holding mechanism design that adjusts to the length and width of various vehicles.The system combines precise positioning using satellite tracking technology,intelligent recognition via OpenCV,and the interconnectivity of IoT.This intelligent vehicle auxiliary handling system can independently identify vehicle positions and plan optimal handling paths,eliminating the traditional reliance on manual operation.It offers efficient and accurate handling,setting a new trend in the handling industry.Additionally,the system integrates seamlessly with parking lot management systems,providing real-time updates on vehicle locations and statuses.This allows managers to monitor the parking lot operations clearly and efficiently.This intelligent coordination greatly enhances overall work efficiency and streamlines parking management.Overall,the innovative design of the intelligent vehicle auxiliary handling system represents a significant breakthrough in both function and performance,gaining user favor with its smooth operation.Looking ahead,continued technological advancements and the expansion of application fields will bring even more vitality and intelligence to societal development.

急性脑卒中应用急诊快捷护理流程的应用效果观察

目的研究急诊快捷护理流程应用于急性脑卒中对提高患者抢救效果的干预作用。方法选取2016年5月—2018年4月本院接诊的急性脑卒中患者100例作为研究对象,利用随机数表法,将其均分为两组。A组抢救治疗中应用急诊快捷护理流程,B组应用常规急诊护理流程。分析两组的抢救情况,比较确诊时间等指标。结果 A组的并发症发生率为6.0%,比B组的20.0%低,组间比较,差异具有统计学意义(P <0.05)。A组的接诊时间与确诊时间比B组短,组间比较,差异具有统计学意义(P <0.05)。A组干预后的NIHSS评分为(4.26±0.83)分,与B组的(9.54±1.75)分比较,差异具有统计学意义(P <0.05)。结论选择急诊快捷护理流程,并将之用于急性脑卒中患者的抢救治疗工作中,可显著减少并发症发生风险,缩短接诊与确诊时间,促进神经功能恢复。