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。

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。

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。

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.

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.

基于ARCS模型的摄影教育游戏设计研究

文章旨在设计一款基于ARCS模型的摄影教育游戏,来提升非艺术生在公共摄影课程中的学习动机。作者团队对ARCS的4个要素进行了深入分析,并将它们融入游戏的设计策略中。分别对游戏的视觉、教学内容、奖励机制和交互模式进行设计实践。最后将游戏投入摄影课堂中做了效果对比测试。结果显示此教育游戏对提升学生的学习动机具有显著作用。文章为模拟摄影教育游戏的设计提供了新的思路,更为提升非艺术生的摄影教学打开了更多的创新空间。

Enhancing fatigue performance of AZ31 magnesium alloy components fabricated by cold metal transfer-based wire arc directed energy deposition through LPB

Cold Metal Transfer-Based Wire Arc Directed Energy Deposition(CMT-WA-DED)presents a promising avenue for the rapid fabrication of components crucial to automotive,shipbuilding,and aerospace industries.However,the susceptibility to fatigue of CMT-WA-DED-produced AZ31 Mg alloy components has impeded their widespread adoption for critical load-bearing applications.In this study,a comprehensive investigation into the fatigue behaviour of WA-DED-fabricated AZ31 Mg alloy has been carried out and compared to commercially available wrought AZ31 alloy.Our findings indicate that the as-deposited parts exhibit a lower fatigue life than wrought Mg alloy,primarily due to poor surface finish,tensile residual stress,porosity,and coarse grain microstructure inherent in the WA-DED process.Low Plasticity Burnishing(LPB)treatment is applied to mitigate these issues,which induce significant plastic deformation on the surface.This treatment resulted in a remarkable improvement of fatigue life by 42%,accompanied by a reduction in surface roughness,grain refinement and enhancement of compressive residual stress levels.Furthermore,during cyclic deformation,WA-DED specimens exhibited higher plasticity and dislocation density compared to both wrought and WA-DED+LPB specimens.A higher fraction of Low Angle Grain Boundaries(LAGBs)in WA-DED specimens contributed to multiple crack initiation sites and convoluted crack paths,ultimately leading to premature failure.In contrast,wrought and WA-DED+LPB specimens displayed a higher percentage of High Angle Grain Boundaries(HAGBs),which hindered dislocation movement and resulted in fewer crack initiation sites and less complex crack paths,thereby extending fatigue life.These findings underscore the effectiveness of LPB as a post-processing technique to enhance the fatigue performance of WA-DED-fabricated AZ31 Mg alloy components.Our study highlights the importance of LPB surface treatment on AZ31 Mg components produced by CMT-WA-DED to remove surface defects,enabling their widespread use in load-bearing applications.

基于ARCS理论的PBL教学法在本科生临床实习教学中的应用

目的探讨基于注意-相关性-自信心-满足动机模式(attention,relevance,confidence,satisfaction,ARCS)理论的以问题为基础的学习(problem-based learning,PBL)教学模式在本科生临床实习教学中的应用。方法选取2020年12月—2022年12月在南京医科大学第一附属医院实习的临床专业本科生作为研究对象。分为对照组(25名)和试验组(26名),对照组采用传统教学模式,试验组采用基于ARCS理论的PBL教学法。比较2组医学生理论知识考核和操作技能考核成绩,以及对疾病基本概念、临床表现、诊断标准、治疗原则的掌握程度。结果试验组理论知识考核成绩[(92.65±3.62)分]和操作考核成绩[(92.59±2.59)分]显著高于对照组理论考核成绩[(87.03±3.52)分]和操作考核成绩[(87.25±2.44)分],差异有统计学意义(P<0.05)。试验组对疾病基本概念、临床表现、诊断标准、治疗原则的掌握程度均优于对照组,差异有统计学意义(P<0.05)。结论与传统教学模式相比,基于ARCS理论的PBL教学法下医学生丰富了理论知识和提高了操作技能,在对疾病基本概念、临床表现、诊断标准、治疗原则的掌握程度也相对提高。

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。

Arc additive manufacturing of gradient hot forging die with shaped waterways

Under the working environment of high temperature and strong load impact,hot forging die is prone to failure which reduces the service life of die.Using arc additive manufacturing in the die cavity,a gradient material hot forging die with high precision,superior per-formance,and conformal cooling channels is developed.This improves the toughness of the die cavity and reduces the working temperature,thereby forming an isothermal field,which is an effective method to enhance the lifespan of the hot forging die.Three kinds of gradient flux-cored wires are designed for the surface of 5CrNiMo steel,and the microstructure and mechanical properties between gradient interfaces were studied.Based on the spatial curved structure of shaped waterways in the hot forging die cavity,a study was conducted on the strategy of partitioned forming for the manufacturing of the die with shaped waterways.In order to avoid interference with the arc gun,the hot for-ging die is divided into four regions,namely the transition region,upper,middle,and lower region,based on a combination of cavity depth and internal U-shaped and quadrilateral structures.The results show that the developed flux-cored wires have good moldability with straight sides of deposited metal under different process parameters and flat surface without cracks,pores and other defects.Under the same working conditions,the life of hot forging die formed by the gradient materials is more than multiple times that of the single material hot forging die,and the temperature gradient field of the shaped waterway die is 7℃/cm smaller than that of traditional straight waterway.

基于ARCS动机模型的创作性戏剧教学设计应用

表演作为播音与主持艺术专业核心课程,在教学计划和人才培养体系中占据重要位置。鉴于目前学生表演基础差、缺乏专业教师团队、教学内容设计不合理、课程评价体系单一等教学痛点,基于ARCS动机模型教学设计思路,我们引入戏剧教育家张晓华的创作性戏剧和Viola Spolin的Theatre Games相结合的教学策略,进行教学方法创新。以理论讲授、热身环节、主题活动、延伸活动紧密结合的阶梯式设计,增添课堂“体验”“扮演”环节,让学生在体验中掌握知识精髓,建立自我概念,形成正确的价值观和认知态度。创新教学评价体系,在过程评价、学生互评中实现对学生个体成长的关注,意在通过教学改革,形成有效教学模式,为表演课程建设提供借鉴参考。

基于ArcGIS和信息量模型的鄂州市矿集区地面塌陷易发性评价

随着鄂州市城市建设的发展,特别是鄂州花湖机场物流配套的建设,用地需求激增,对矿集区进行地面塌陷易发性评价尤为必要。本文针对鄂州市最有代表性的地面塌陷发育特点,选取采空区影响范围、地质构造、岩溶发育特征、覆盖层厚度、水文地质条件5种因子,利用Arc GIS平台和信息量模型,对鄂州市矿集区地面塌陷进行易发性评价。结果表明,评价中地面塌陷高易发区面积54.51 km^(2),占研究区的31.62%,主要分布在泽林镇中心城区和汀祖镇丁坳村、刘显村;实际验证该区域已发生28处地面塌陷,占鄂州地面塌陷的93.33%。评价结果可以为矿集区地面塌陷防治和建设规划提供参考。

Effect of chromium on hot corrosion behavior of arc-sprayed NiCr coatings

In this article,NiCr coatings with chromium content of 13%,27%and 41%were prepared by arc spraying.They were exposed in molten salts(NaCl-Na_(2)SO_(4))at 800℃for 200 hours.The effect of chromium content on the hot corrosion behavior of the coatings was in-vestigated.X-ray diffraction(XRD)and scanning electron microscope with energy dispersion spectrum(SEM-EDS)were used to analyze the phase compositions,morphologies and chemical compositions of the coatings.The results show that NiCr13 coating exhibited the worst hot corrosion resistance due to the low chromium content,which resulted in NiO being the major reaction product.It should be noted that the hot corrosion resistance of NiCr27 coating was better than that of NiCr41 coating.The basic fluxing of Cr_(2)O_(3) lowered its protection during the hot corrosion process and led to the formation of porous Cr_(2)O_(3) on the NiCr41 coating.The molten salts accelerated the oxidation reac-tion resulting in thicker and porous oxide scales formed on the surfaces of coatings.

ARCS模型视角下武术游戏化教学质量评价方法研究

研究ARCS模型视角下武术游戏化教学质量评价方法,促进武术教学质量良性发展。设计ARCS模型武术游戏化教学质量评价结构,通过定义模块激发学生学习武术兴趣,设计模块依据学生兴趣设立武术游戏化课堂,预设与学生相对应武术闯关游戏,通过在游戏中学习武术专业知识,激发模块通过武术游戏化课堂的学习环境、武术知识建立学生武术学习自信心;评价模块通过构建教学质量评价指标体系,采用模糊综合评价算法,依据各指标获取教学质量综合评价结果,依据评价结果不断完善教学设置,提升学生武术学习满意度。实验说明:该方法设计武术游戏化教学可提升中小学学生武术学习兴趣度,增加武术课堂教学效果,同时该方法能客观表达武术教学质量评价结果。