A spatiotemporal evolution model of a short-circuit arc to a secondary arc based on the improved charge simulation method

The initial shape of the secondary arc considerably influences its subsequent shape.To establish the model for the arcing time of the secondary arc and modify the single-phase reclosing sequence,theoretical and experimental analysis of the evolution process of the short-circuit arc to the secondary arc is critical.In this study,an improved charge simulation method was used to develop the internal-space electric-field model of the short-circuit arc.The intensity of the electric field was used as an independent variable to describe the initial shape of the secondary arc.A secondary arc evolution model was developed based on this model.Moreover,the accuracy of the model was evaluated by comparison with physical experimental results.When the secondary arc current increased,the arcing time and dispersion increased.There is an overall trend of increasing arc length with increasing arcing time.Nevertheless,there is a reduction in arc length during arc ignition due to short circuits between the arc columns.Furthermore,the arcing time decreased in the range of 0°-90°as the angle between the wind direction and the x-axis increased.This work investigated the method by which short-circuit arcs evolve into secondary arcs.The results can be used to develop the secondary arc evolution model and to provide both a technical and theoretical basis for secondary arc suppression.

高职院校学生ARCS学习动机模型的探索与实践

本研究利用发放调查问卷、查阅文献和现场访谈等方法,结合ARCS学习动机模型,对现阶段高职院校学生学习现状进行调查研究。结合调查分析结果,借助ARCS学习动机模型进行教学设计并实施教学,调动学生学习的积极性,激发学生的学习动机,提高了学生的学习兴趣和学习能力。

OBE-ARCS导向的化学工程专业学位研究生课程体系建设和课堂教学模式创新

立足学校理工交叉学科特色,化学工程专业以OBE理念为指导,融合产学研用多要素,对专业学位研究生的核心课程体系进行重构;基于ARCS动机模型,创新研究生课程教学模式;协同专业、课程和教材思政,构建一体化育人机制;依托工程实践基地建设,强化理论与工程实践的结合。基于以上举措构建的“四维一体”育人模式将研究生的知识学习、能力培养、意识强化、专业素养提升紧密融合,在培养高质量应用型人才方面取得了显著成效。

基于ARCS模型的翻转课堂教学设计

以“取样定理”为例,提出采用ARCS模型进行翻转课堂教学设计的案例。教学内容设计注重核心价值观的传播,从取样定理形成的历史脉络引出课程思政;运用多种教学手段,提升学生注意力;重视学习内容的关联设计,学生端倚重信息技术应用,及时反馈,提升学生自信度;学习评价注重应用性,提升学习满意度。教学实施结果表明,该教学设计能调动学生的课堂热情,师生满意度高。

ARCS动机模型混合学习造纸英语听力App设计与开发

ARCS动机模型是1987年美国学者研究并提出的。信息技术的迅速发展,促使该动机模型在多媒体产品开发、课件设计及教育App领域得以广泛应用,并以此来调动学习者的积极性。依托ARCS动机模型对造纸英语听力App进行设计的主要目的是提升学习者对时间的利用率和学习满意度。基于此,针对用户对造纸英语听力App的学习需求,与现有技术相结合,对当前只限于“速记”“跟读”的学习英语听力App进行创新,提供新的研发思路与方向。

ARCS模型视角下高职英语教学资源建设与应用研究

基于ARCS模型视角的高职英语教学资源平台建设和应用,坚持以学习者为中心,以整体化、系统化、标准化、科学化、合作性、共享性、循环性改进为原则,围绕高职学生岗位英语语言技能和职业素养目标,构建高职英语课程教学资源库和教学资源共享平台,完善学习成果考核评价体系,建立质量评估和诊改机制,多举措提升教改能力,促进数字化技术与教学改革实践深度融合与双向赋能。

基于ARCS激励模型的老年健步走运动产品设计研究

为提高老年群体参与健步走运动锻炼的积极性,文章从运动激励的角度出发开展老年健步走运动相关的产品设计研究,并利用计算机化行为研究的E-Prime软件,建立SAM情绪测试实验程序。同时,通过对实验所得的情感体验数据进行单因素方差分析,证实引入ARCS模型的健步走运动对于激发老年人积极情绪价值的有效性,并得出ARCS模型激励要素的优先性,基于此提出老年健步走产品设计的策略,以期为老年运动相关产品设计提供新的思路。

基于ARCS模型设计的VR实训课程教学效果分析

以基站运行与维护实训课程为例,基于ARCS模型进行教学设计,关注学生学习感受的四个方面:注意、关联、信心、满足感。同时结合情境认知理论和建构主义理论,通过VR实训课程教学,激发学生学习的兴趣和动机,分析实训课程教学设计,增强课程教学效果。

基于ARCS动机模型的“中药鉴定实习”实践教学设计与应用

ARCS动机模型在实践教学中被广泛应用,对激发和维持学生学习动机起着重要的作用。文章以ARCS动机模型为基础对“中药鉴定实习”进行课堂教学设计,进而提升学生的学习动力。同时,该课程依托内蒙古医科大学位于河北安国的实习基地进行为期一周的实践教学,以期让学生对中药学专业有一个全新的认识,深入了解中药学相关工作。该课程的实践教学设计与应用,不仅有效地激发了学生的学习兴趣,调动了学生的学习热情,而且为其今后的学习深造和工作奠定了良好的基础,同时也为学生的职业生涯规划提供了良好的帮助。

基于TARGET融合ARCS动机模型的应用统计学课程教学改革研究

学生的学习动机直接关系到课程教学目标的达成,激发学习动机是推动课程教学改革的应有之义。将TARGET和ARCS学习动机模型引入应用统计学课程教学,分析当前教学中存在的动机问题,提出有效激发学生动机的教学方案和实践策略,结果既可促进应用统计学课程教学质量提升,也可为其他相似课程教学设计提供参考借鉴。

ARCS动机模型下右玉精神融入高校思政教育探析

右玉精神蕴涵的深厚思想精髓是我国高校思想政治教育的重要资源和优秀教材,能够很好地帮助当代青年学生提升自身政治素养和传承艰苦奋斗的精神。文章基于ARCS动机模型,从“注意、关联、信心、满意”四个环节,归纳总结了右玉精神融入高校思想政治教育过程中面临的现实困境,如学习氛围不浓且教学模式陈旧、学习内容机械生硬、教学手段陈旧单调、学习效果不佳学生满意度不高,尝试提出营造氛围改变教学模式、与时俱进设计教学内容、完善教学评价反馈机制、情景教学并注重成果展示四个解决路径。

ArcCHECK Machine QA工具在医用直线加速器质量保证中的应用效果

目的探讨ArcCHECK Machine QA工具在医用直线加速器质量保证中的应用效果。方法利用ArcCHECK Machine QA工具和ArcCHECK体模对医用直线加速器进行性能测试,项目包括机架角度、机架旋转速度、机架旋转中心、多叶准直器和铅门位置的一致性、机架旋转出束时的平坦度和对称性,评估该工具在医用直线加速器质量保证中的应用效果。结果旋转模式下机架平均旋转速度为3.6 deg/s,最大偏差约0.5 deg/s;机架旋转等中心形成的平均半径为0.4 mm,多叶准直器与铅门的最大距离正、负差异平均值分别为0.7 mm、-0.7 mm;旋转出束模式下Y方向的平坦度为1.8%,Y方向的对称性为1.1%,X方向的对称性为4.3%。结论ArcCHECK Machine QA工具可用于医用直线加速器常规及容积调强出束性能质量保证。

Oxygen-assisted zinc recovery from electric arc furnace dust using magnesium chloride

Electric arc furnace(EAF)dust is an important secondary resource containing metals,such as zinc(Zn)and iron(Fe).Recover-ing Zn from EAF dust can contribute to resource recycling and reduce environmental impacts.However,the high chemical stability of ZnFe_(2)O_(4)in EAF dust poses challenges to Zn recovery.To address this issue,a facile approach that involves oxygen-assisted chlorination using molten MgCl_(2)is proposed.This work focused on elucidating the role of O2 in the reaction between ZnFe_(2)O_(4)and molten MgCl_(2).The results demonstrate that MgCl_(2)effectively broke down the ZnFe_(2)O_(4)structure,and the high O2 atmosphere considerably promoted the sep-aration of Zn from other components in the form of ZnCl_(2).The presence of O2 facilitated the formation of MgFe_(2)O_(4),which stabilized Fe and prevented its chlorination.Furthermore,the excessive use of MgCl_(2)resulted in increased evaporation loss,and high temperatures pro-moted the rapid separation of Zn.Building on these findings,we successfully extracted ZnCl_(2)-enriched volatiles from practical EAF dust through oxygen-assisted chlorination.Under optimized conditions,this method achieved exceptional Zn chlorination percentage of over 97%within a short period,while Fe chlorination remained below 1%.The resulting volatiles contained 85wt%of ZnCl_(2),which can be further processed to produce metallic Zn.The findings offer guidance for the selective recovery of valuable metals,particularly from solid wastes such as EAF dust.

基于ARCS的ASD儿童绘本角色设计研究

目的为提升ASD儿童情绪学习动机,探究不同角色形象在基本情绪学习中的激发作用,以绘本角色造型为切入点,为绘本角色设计和干预训练提供参考。提出一种基于ARCS动机模型的角色设计研究方法。方法首先,结合ARCS动机维度,建立了一套适用于绘本角色研究的指标体系。在文献研究的基础上,筛选出7项代表性眼动指标和1项情绪匹配数据,并利用眼动仪收集这些指标的实验数据;其次,采用熵权法计算眼动实验客观指标的权重,并使用逼近理想解法(TOPSIS)确定三大角色样本类型的综合排序。结果研究发现,与其他类型的角色相比,在ASD儿童中,器物角色的动机反馈效果更佳,并且这几类角色对ASD儿童的眼动指标都有不同程度的影响,因此每个角色的干预效果也不尽相同。结论将ARCS动机理论模型引入绘本角色设计中,结合眼动实验解析动机策略与角色特征元素之间的关联性,能更有效地改善干预训练中缺乏学习动机的情况;建立评价体系有助于为后续相关设计提供研究思路。

基于ARCS动机模型的高中化学教学策略研究

现如今高中化学教学面临着诸多问题与挑战,其中包括学生学习动机的不足、学习兴趣的下降、学习自信心的缺失以及学习满意度的低下等问题。本文基于ARCS动机模型,探讨了针对上述目前高中化学教学面临的问题,提出“以学生发展为本”的高中化学教学策略,为“核心素养为本”的高中化学教学提供新的思路和方法。

Geochemistry of island arc assemblage in the Eastern Desert of Egypt and the role of Pan-African magmatism in crustal growth of the Arabian–Nubian Shield:A review

Neoproterozoic island arc assemblage of the Arabian–Nubian Shield(ANS)in the Eastern Desert(ED)of Egypt comprises juvenile suites of metavolcanics(MV),large amounts of meta-sedimentary rocks(MS),and voluminous metagabbros-diorites(MGD)and syn-tectonic intrusions of older granitoids(OG).We report here the updates of these four rock units in terms of classification,distribution,chemical characteristics,geodynamic evolution,metamorphism,and ages.In addition,we discuss these integrated data to elucidate a reasonable and reliable model for crustal evolution in the ANS.The main features of these rock units indicate their relation to each other and the geodynamic environment dominated by early immature oceanic island arcs to primitive continental arcs.Integrated information of the island arc metavolcanic and plutonic rocks(gabbros,diorites,tonalites,and granodiorites)furnish evidence of the genetic relationships.These include proximity and a coeval nature in the field;all protolith magmas are subalkaline in nature following calc-alkaline series with minor tholeiitic affinities;common geochemical signature of the arc rocks and subduction-related magmatism;their similar enrichment in LREEs;and similar major element compositions with mafic melts derived from metasomatized mantle wedge.The volcano-sedimentary and the OG rocks underwent multiphase deformation events whereas the MGD complexes deformed slightly.Based on the magmatic,sedimentological,and metamorphic evolutions constrained by geochronological data as well as the progressive evolutionary trend from extensional to compressional regimes,a possible gradual decrease in the subducted slab dip angle is the most infl uential in any geodynamic model for arc assemblage in the ED of Egypt.

Experimental Study on Wire Melting Control Ability of Twin-Body Plasma Arc

The twin-body plasma arc has the decoupling control ability of heat transfer and mass transfer,which is beneficial to shape and property control in wire arc additive manufacturing.In this paper,with the wire feeding speed as a characteristic quantity,the wire melting control ability of twin-body plasma arc was studied by adjusting the current separation ratio(under the condition of a constant total current),the wire current/main current and the position of the wire in the arc axial direction.The results showed that under the premise that the total current remains unchanged(100 A),as the current separation ratio increased,the middle and minimum melting amounts increased approximately synchronously under the effect of anode effect power,the first melting mass range remained constant;the maximum melting amount increased twice as fast as the middle melting amount under the effect of the wire feeding speed,and the second melting mass range was expanded.When the wire current increased,the anode effect power and the plasma arc power were both factors causing the increase in the wire melting amount;however,when the main current increased,the plasma arc power was the only factor causing the increase in the wire melting amount.The average wire melting increment caused by the anode effect power was approximately 2.7 times that caused by the plasma arc power.The minimum melting amount was not affected by the wire-torch distance under any current separation ratio tested.When the current separation ratio increased and reached a threshold,the middle melting amount remained constant with increasing wire-torch distance.When the current separation ratio continued to increase and reached the next threshold,the maximum melting amount remained constant with the increasing wire-torch distance.The effect of the wire-torch distance on the wire melting amount reduced with the increase in the current separation ratio.Through this study,the decoupling mechanism and ability of this innovative arc heat source is more clearly.

Effect of contact materials on the transient characteristics of vacuum arc plasma and anode erosion

In this study, the mechanisms of the anode phenomena and anode erosion with various contact materials were investigated. Arc parameters were calculated, and the anode temperature was predicted with a transient self-consistent model. The simulation results predicted a constricted arc column and obvious anode phenomena in Cu–Cr alloy contacts than in W–Cu alloy contacts.This observation could be the reason for the concentrated anode erosion in Cu–Cr alloys. For the contacts made by pure tungsten(W) and W–Cu alloy, the anode temperature increased rapidly because of the low specific heat of W. However, the maximum energy flux from the arc column to the anode surface was lower than in other cases. The simulation results were compared with experimental results.

Customized heat treatment process enabled excellent mechanical properties in wire arc additively manufactured Mg-RE-Zn-Zr alloys

Customized heat treatment is essential for enhancing the mechanical properties of additively manufactured metallic materials,especially for alloys with complex phase constituents and heterogenous microstructure.However,the interrelated evolutions of different microstructure features make it difficult to establish optimal heat treatment processes.Herein,we proposed a method for customized heat treatment process exploration and establishment to overcome this challenge for such kind of alloys,and a wire arc additively manufactured(WAAM)Mg-Gd-Y-Zn-Zr alloy with layered heterostructure was used for feasibility verification.Through this method,the optimal microstructures(fine grain,controllable amount of long period stacking ordered(LPSO)structure and nano-scaleβ'precipitates)and the corresponding customized heat treatment processes(520°C/30 min+200°C/48 h)were obtained to achieve a good combination of a high strength of 364 MPa and a considerable elongation of 6.2%,which surpassed those of other state-of-the-art WAAM-processed Mg alloys.Furthermore,we evidenced that the favorable effect of the undeformed LPSO structures on the mechanical properties was emphasized only when the nano-scaleβ'precipitates were present.It is believed that the findings promote the application of magnesium alloy workpieces and help to establish customized heat treatment processes for additively manufactured materials.

An Overview on the Composition and Age of Upper Crust of Proto-Tethyan Lajishan Intra-oceanic Arc,NE Tibet Plateau

Identification and anatomy of oceanic arcs within ancient orogenic belt are significant for better understanding the tectonic framework and closure process of paleo-ocean basin.This article summarizes the geological,geochemical,and geochronological characteristics of upper crust of Proto-Tethyan Lajishan intra-oceanic arc and provides new data to constrain the subduction evolution of the South Qilian Ocean.The intra-oceanic arc volcanic rocks,including intermediate-mafic lava,breccia,tuff,and minor felsic rocks,are distributed along southern part of the Lajishan ophiolite belt.Geochemical and isotopic compositions indicate that the intermediate-mafic lava were originated from depleted mantle contaminated by sediment melts or hydrous fluids,whereas the felsic rocks were likely generated by partial melting of juvenile mafic crust in intra-oceanic arc setting.Zircons from felsic rocks yield consistent and concordant ages ranging from 506 to 523 Ma,suggesting these volcanic rocks represent the relicts of upper crust of the Cambrian intra-oceanic arc.Combined with the Cambrian forearc ophiolite and accretionary complex,we suggest that the Cambrian intra-oceanic arc in the Lajishan ophiolite belt is belonging to the intra-oceanic arc system which was generated by south-directed subduction in the South Qilian Ocean at a relatively short interval between approximately 530 and 480 Ma.