共查询到20条相似文献，搜索用时 534 毫秒
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商建平 《兰州石化职业技术学院学报》2007,7(4):6-7
通过对承受温差载荷的厚壁球形封头进行弹性应力分析,得出了厚壁球形封头温差应力的计算式,并得到了温差应力的分布状况,为高压厚壁球形封头的设计提供了理论基础. 相似文献
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运用有限元法,考虑封头的结构、封头与简体的连接形式、开孔位置、接管与封头的连接结构等因素,对受内压的凸形封头(球形封头、椭圆形封头、碟形封头及锥形封头)进行了应力分析计算。 相似文献
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由经典力学理论,对于球形封头开孔应力集中问题,大都采用近似计算公式.而数值模拟技术能克服设计的盲目性,能比较精确地获得复杂结构的各种工况下的应力分布情况,对结构的设计、改进提供重要参考价值. 相似文献
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厚壁球形封头的弹性应力分析 总被引：1，自引：1，他引：1
马秉骞 《兰州石化职业技术学院学报》2002,2(3):22-24
厚壁球形封头在内压力作用下处于三向应力状态 ,可以按类似于拉美公式的分析方法对其三向应力作近似分析。基于这种认识 ,在厚壁球形封头上取一微元体 ,通过分析其受力、位移、变形协调及应力应变关系 ,找出了求解应力的微分方程 ,并根据边界条件得出了厚壁球形封头三向应力的计算公式 ,即径向应力为 pK3 - 1(1- R30r3 ) ,环向应力和经向应力相等 ,其值为 pK3 - 1(1+ R302r3 )。 相似文献
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封头边缘应力自动测试实验装置的研制 总被引：4，自引：0，他引：4
阐述了封头边缘应力自动测试实验装置的研制过程，并将过程控制技术和先进的检测手段相结合，介绍了该实验装置主要组成部分的操作原理，在完成其组装和调试后，对封头边缘过渡区的应力分布规律进行了测试，所得结果的分布曲线规律与有限元分析结果的分布规律相吻合，可以满足实验教学的需要。 相似文献
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《实验室研究与探索》2018,(12)
薄壁容器椭圆封头应力测定实验是过程装备与控制工程专业的核心实验,也作为能源与动力工程等专业的开拓性试验设置,主要用于学生采用电阻应变法进行应力测定知识和技能训练。然而,随着工业技术的发展,采用数值分析的方法解决工程问题已经成为工程技术人员和科研人员的必备技能,但目前教学环节缺乏相应的实践训练。针对薄壁容器椭圆封头应力测定实验提出改革措施,增加了对数值积分、有限元软件应用、应力状态分析方面的训练内容,对于提高学生综合运用现代化数值方法和工具解决复杂工程问题的能力具有一定的意义。 相似文献
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超长钢筋混凝土结构温度应力分析一直是设计人员所关注的课题。文章结合工程实例对超长结构温度应力进行分析，提出了温差的取值方法，并采用PMSAP有限元软件对超长结构进行计算，分析其变形和内力特点，总结出了设计中减小温度应力的措施。 相似文献
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曲丽秋 《鞍山师范学院学报》2014,(5):40-43
新型城镇化建设已经成为我国经济增长和社会发展的强大引擎,也必将成为我国现代化建设进程中的大战略。鞍山作为沈阳经济区沈辽鞍营城际连接带的一部分及重要节点,在振兴东北老工业基地,推进新型城镇化建设中的重要性不言而喻。笔者从新型城镇化建设过程中产业与城市统筹发展的角度入手,结合鞍山市新型城镇化建设中产业与城市一体化发展的情况进行实证分析,以期为其存在的问题提出相应的对策和建议。 相似文献
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张月瀛 《黄河科技大学学报》2012,40(4):36-40
中原地区属于传统的农业区,要实现＂三化＂协调发展、促进民生改善,都需要财政的大力支持。建设中原经济区不仅可以促进本区域经济社会发展,还具有强大的正外部性,既是破解河南发展难题的必然要求,也是全国现代化建设进程中必须解决的重大战略问题。所以,要加大对中原经济区农业、新型城镇化、产业结构优化升级和民生建设方面的财政支持力度,通过财政体制机制的完善,更好地发挥财政引导各地科学发展的作用,推动中原经济区更好的发展。 相似文献
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P.J. Harris S.A. Campbell Casey T. Westbury G. Florida-James 《Journal of Further & Higher Education》2016,40(6):824-845
Students suffer from stress as a result of many factors, including educational unpreparedness, financial strain and inability to integrate socially. This mixed methods study aimed to investigate stress levels of undergraduate students in a post-1992, Scottish university and the potential for measures of stress to act as an indicator of a student’s intention to continue. The study sampled primarily engaged students as tests were administered during timetabled classes and required the students’ voluntary participation. The level of perceived stress reported by these students appeared to be high (mean PSS-14 scores of 18.42 (SD 8.452) and 24.57 (SD 8.969) for males and females, respectively) and was coupled with intention to drop out across all study levels (12.1% of students sampled reported ‘seriously considered dropping out’). Perceived stress score predicted a student’s intention to withdraw but this association did not transfer to actual withdrawal, suggesting that other factors, most likely coping mechanisms, play a part in mediating the withdrawal behaviour. Unfortunately, despite the seemingly high levels of stress and potential worry over dropout, students are reluctant to seek support and many were unaware of the support services available through the university. Given the engaged nature of these students, their feelings are unlikely to be made known to staff as they will not necessarily register on non-attendance lists or be flagged because of missing assignments, which are often used as indicators of potential problems. This brings to light a previously hidden student group that may benefit from additional support to prevent unnecessary underachievement or dropout. 相似文献
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利用大型有限元软件ANSYS/LS-DYNA的模拟功能,对轧辊的裂纹尖端开裂模式进行了模拟分析。在将裂纹尖端区域细化的基础上,得出含表面裂纹的热轧工作辊两个裂纹尖端的开裂模式是不同的,并且随着轧制深入以及裂纹扩展规律的影响,出现了裂纹尖端局部塑性区以及材料局部的卸载情况,使应力强度因子K以及J积分之间不再满足在线弹性过程中的换算关系形式。 相似文献
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Ruth Dann 《Curriculum Journal》2013,24(4):352-374
AbstractThis paper constructs a theoretical argument to frame feedback as a relational concept. It addresses contemporary concern that formative assessment, of which feedback is a part, is under theorised. The arguments presented link to existing theoretical and research evidence. The paper also challenges the dominant policy discourse in high stakes assessment contexts in which feedback is typically seen in technised ways to serve the need to raise measured pupil outcomes. Vygotsky’s notion of the zone of proximal development is explored as a relational space in which both teachers and learners understand differences between learning ‘now’ and learning ‘next’. Extending Vygotsky’s perspective, a socio-cultural perspective is offered, by considering the role of ‘others’, ‘language’, ‘activity’ and ‘identity’, as part of the process of sharing and understanding feedback in classrooms. The work of Holland et al. (1998), Bakhtin (1986) are central to the developing argument. The paper reveals feedback as a complex situated process, requiring mediated dynamic interaction, where feedback is appropriated as a cultural artefact by its participants. The implications of such an articulation demands a greater sense of understanding pupils’ roles in feedback and the importance of teachers enabling pupils to see themselves in new ways as future learners. 相似文献
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A questionnaire survey of 710 Maltese primary schoolteachers revealed that the level of teacher stress, job satisfaction and career commitment was constituted differently in some of the teacher demographic subgroups. A principal components analysis of the stress ratings of 20 items covering various aspects of the teacher's work environment yielded four factors described in terms of ‘pupil misbehaviour’, ‘time/ resource difficulties’, ‘professional recognition needs’ and ‘poor relationships’. Teacher sex and ability‐group taught interacted significantly with the stress factors. Results also showed that teachers who reported greater stress were less satisfied with their job and less committed to choose a teaching career were they to start life over again. Moreover, the association between the general measure of job stress and the stress due to each of the four stress factors was strongest for ‘pupil misbehaviour’ and ‘time/resource difficulties’. Of the four factors, ‘professional recognition needs’ had the strongest inverse relationship with job satisfaction and career commitment. 相似文献
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Judith Duncan Chris Bowden Anne B. Smith 《International Journal of Early Years Education》2006,14(1):1-13
Parental support has been an increasingly essential part of New Zealand early childhood (EC) education services over the last 20 years. This support has taken many shapes and forms over this time period, and has depended on the differing philosophies of the EC education services. What this support ‘looks like’ and how it is delivered is directly connected to the goals and aims of these services. This paper will discuss the results from a small qualitative study that looked at how three New Zealand EC centres—two kindergartens and one child care centre—supported family resilience; that is, the ability of an individual and family to ‘cope’ with and ‘recover’ from significant adversity or stress, in ways that are not only effective but may result in increased ability to ‘respond’ to and ‘protect’ their families from future adversity. From semi‐structured interviews with teachers, parents, and family support services associated with each of the three centres, the concept of planned parent education programmes, as meaningful support, is re‐examined in the light of the ideas of a ‘gossip’ or a ‘good yack’. This research was funded by the New Zealand Ministry of Social Development. 相似文献
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Thomas Hardy(1840-1928)is a famous British Novelists.His excellent works have a far-reaching significance to the later gen erations.Treating his The Mayor of Casterbridge as a text,this paper is aimed to detect Hardy’s implied meanings of the symbols in a through textual analysis.This thesis is divided into three parts.The first part is the the symbol of the bridges.The second part deals with the symbol of the mel ody.Part three explores other symbols in The Mayor of Casterbridge.The symbols are all deliberately chosen in this book by the author to transmit his tragic view.Through the symbols of the bridges,the melody,the church,the tractor,the railway…,the author’s tragic view is well presented.By the research of each of those three parts,the conclusion of Hardy’s functions of the symbols can be drawn. 相似文献