共查询到19条相似文献，搜索用时 109 毫秒
1.
舒神州 《长江工程职业技术学院学报》2009,26(1):50-52
针对热锯片锯切大规格圆钢时出现锯片体振动较大的问题,进行了锯片振动特性的有限元仿真,并就振动的抑制方法进行了探讨,分析了锯口宽度与夹紧比、钢种、锯切温度、锯片直径间的关系。 相似文献
2.
钟浩源 《青少年科技博览(中学版)》2004,(10)
选题的发现我在少年宫制作科技作品时,经常要使用钢锯。钢锯的锯片很容易磨钝、折断, 需要经常更换。由于锯片被螺母牢牢地固定在锯弓上,所以,拆锯片时,需先松开螺母。有时用手很难拧松螺母,要用到钳子才能装拆锯片。锯片装上时,还需要靠目测调整锯片的平衡,以免使用时再折断锯片。可见,装拆锯片这一“拆—装—调”的过程,十分费时、费劲,还容易造成锯片大量消耗。用什么办法使更换锯片省时、省力呢?能否设计一种可快速、准确地更换锯片的锯弓呢?我注意到儿童玩的滑板车支撑杆上有一个定位器,它通过一个把手的扳开扳合,来控制滑板研究过程只… 相似文献
3.
采用有限元分析软件ANSYS,对轧钢厂金属小锯片的固有特性进行了系统研究。通过对锯片在打孔、开槽情况下固有频率及振型的计算分析发现:打孔对锯片固有频率无太大影响,但对降噪影响较大;开环形槽对五阶以上固有频率影响相对明显。 相似文献
4.
丁紫阳 《北京工业职业技术学院学报》2023,(4):16-19
近年来,金刚石锯片广泛应用于硬脆材料加工,虽然取得了显著的加工效果,但是仍然存在一些问题。为了解决金刚石锯片应用过程中的常见问题,对金刚石锯片应用的主要失效形式及性能提升影响因素进行研究。结果表明：通过控制金刚石的选择、胎体配方设计、烧结工艺、锯切参数等因素,可以有效解决金刚石锯片应用过程中的失效问题。 相似文献
5.
以锯片对磨机床为研究对象,利用Pro/E三维软件建立主轴系统三维模型.利用分析软件ANSYS对机床主轴进行模态分析、静力分析,在此基础上得出主轴的固有频率、振型以及受力、变形情况,并利用ANSYS对主轴进行优化设计,为锯片对磨机床的开发提供可靠的设计依据. 相似文献
6.
本提出了金刚石锯片基体热处理的改进方法——加压淬火冷却 加压回火,并对此方法作了具体的试验、分析和总结,有助于提高现有基体的热处理水平。 相似文献
7.
介绍了圆盘锯片切割、锯条切割和串珠绳等三种金刚石主要切割技术,分析了三种切割技术的切割机理、切割效率和经济效果,对石材加工厂合理选择切割技术起到了一定的指导作用。 相似文献
8.
通过对内圆锯片上的单颗金刚石磨粒进行运动状况的分析,推导计算单颗金刚石磨粒的切削厚度;通过理论推导锯切时内圆锯片与工件的接触弧长,建立内圆锯片所受锯切力与切入深度、进给速度、锯片转速和工件直径之间的关系. 相似文献
9.
10.
周嘉琦 《辽宁科技学院学报》2014,(3):18-19
文章采用TC-436氮氧仪对分别使用碳化硅锯片打磨、砂轮打磨和板挫打磨后的氧试样在各种实验条件下进行分析,把分析数据归类比较,得出用板挫、酸处理后的试样表面光洁度最好,二次污染物去除的最干净,可以保证分析结果的精确度和准确度。 相似文献
11.
石红英 《延安教育学院学报》2006,20(3):44-45,61
马尔库塞在看到发达资本主义社会表面繁荣的同时也始终关注着现实的社会和现实的人,关注着人的本质和价值。他看到生活于发达工业社会中的人虽然过着舒适、富裕的物质生活,其精神生活却是贫乏的、空虚的,呈现出一种单面性,为此他对其进行了尖锐的批评。 相似文献
12.
Dale Franzwa 《Educational technology research and development : ETR & D》1973,21(2):209-223
Summary The present study investigated the relationships of meaningfulness, picture detail, and presentation mode on visual learning.
Subjects, 123 broadcasting students at Brooklyn College, viewed slides of animal pictures previously classified by judges
into high-and low-meaningful groups. All Ss saw both high-and low-meaningful stimulus items. Half saw the stimulus items as
full-color pictures while the other half saw them as line drawings. In addition, one-third saw the stimulus items as pictures
presented alone, one-third saw them as pictures with each animal name printed underneath its picture, and one-third saw the
pictures (without printed names) accompanied by the spoken animal name as each slide was shown. Following presentation of
stimulus slides, Ss were shown a series of full-color test slides containing dummy items randomly intermixed with stimulus
items. During two showings of test slides, Ss first indicated those animals recognized from the learning trial and second,
wrote down those animal names they knew.
Results included significant main effects on recognition accuracy for meaningfulness and presentation mode in addition to
significant interactions for meaningfulness-by-mode and mode-by-picture-detail. A significant main effect of presentation
mode resulted for correctly named stimulus items. Three significant main effects (meaningfulness, picture detail, and mode)
and one significant interaction (mean-ingfulness-by-picture-detail) were obtained on error scores. 相似文献
13.
张振国 《华南师范大学学报(社会科学版)》2012,2(2):109-113,158
“假传”文滥觞于韩愈的《毛颖传》.唐代是“假传”文的发轫期,宋元是“假传”文的发展和分化期,明代是“假传”文的高峰期和从俗期,清代是“假传”文的复归淳雅期,民国初年“假传”文曾再度繁荣,“五四”以后随着文言的衰落,“假传”文体走向式微. 相似文献
14.
This study investigated children's understanding of others' intentions in a social learning context. Specifically, it investigated whether knowing an adult's prior intention before the adult gives a demonstration influences what children learn from the demonstration. In the five main experimental conditions, ninety-six 2-year-old children watched as an experimenter (E) pulled out a pin and opened the door of a box. Children in two No Prior Intention conditions saw this demonstration alone or paired with an irrelevant action. Children in three Prior Intention conditions knew what E was trying to do before the demonstration: they first saw E either attempt unsuccessfully to open the door, or visit and open several other containers, or they first saw that the door opened. Children opened the box themselves more often in each of these three conditions than in the two No Prior Intention conditions, even though children in all five conditions saw the exact same demonstration of how to open the box. 相似文献
15.
20世纪初期中国知识分子访问苏联有不同的心得体会,他们在苏联看到了新的希望,受到了鼓舞,也看到了乌托邦之梦的破灭。这段经历丰富了知识分子的阅历,为他们未来的人生选择奠定了基础。 相似文献
16.
Christiane Vandenplas-Holper Isabelle Roskam Anne-Marie Fontaine 《European Journal of Psychology of Education - EJPE》2010,25(1):1-17
Using Harter’s (Child Dev 53(1):87–97, 1982) perceived competence scale, this study integrates several paradigms related to the issues of self-perceived competence,
stability or change and attributional theory. It examines how 268 Belgian and Portuguese fifth graders consider their scholastic,
social and physical competence at present and in a retrospective or prospective time perspective. The children were also asked
to rate the causes of their self-perceived competence-related stability or change. Nearly all of the children who saw change
indicated that they had changed/would change in a positive way. Children more often thought that they would change in the
future than that they had changed in the past. Children who saw change also made more internal attributions (effort and ability)
than children who saw only stability. Finally, the results varied consistently between the Belgian and the Portuguese samples,
indicating cross-cultural differences which are tentatively illuminated by macro-systemic considerations referring to educational
policy in the two countries. 相似文献
17.
笔者透过一个对印象派知之甚少的观者的视角，看到和感受到了陌生而又似曾相识的印象派绘画，并对中国传统山水画和印象派绘画进行了比较。 相似文献
18.
Tim Rajan 《Instructional Science》1991,20(2-3):89-110
This paper describes an approach to evaluating the usefulness of an Animated Program Tracer (APT) in communicating run-time information to novice Prolo programmers. The method used in the evaluation consists of a set of programs which have been specially designed to elicit how novices think Prolog programs are executed, and thus to reveal how accurate their model of program execution is. Two experiments are reported. The first determines the misconceptions that novices hold about the runtime actions of the Prolog interpreter, and produces six different categories of misconception. The second experiment investigates the ability of APT to communicate run-time information to novice Prolog programmers. A scoring technique was used to interpret subjects' answers, and shows that there was a significant improvement in the scores of the group who saw programs traced by APT when compared with a control group who saw no trace. 相似文献
19.
Magnus Hultén 《History of education》2013,42(5):622-637
The decades following the Second World War saw strong technological development and economic growth. They also saw ‘the advent of technology education’, a period of extensive curriculum development in this field. But what was done and why? In order to obtain a better understanding of the historical roots of technology education, in this study the mid-century school reforms in Sweden are examined and, more specifically, the birth of the new subject of Technology (Teknik) in compulsory schools. In this article, the political forces driving the introduction and shaping of this new subject are emphasised. In a time of rapid transformations of educational systems and labour markets, the term Teknik proved to be a useful concept for policy-makers and reform technocrats. However, the subject came to re-create the inequalities of the earlier differentiated school system, despite its presence within the framework of a school ‘for all’. 相似文献