排序方式： 共有14条查询结果，搜索用时 15 毫秒
2.
4.
课本第130页:“19世纪70年代后期,欧洲资本主义各国工人的人数猛增,因巴黎公社失败一度处于低潮的国际工人运动,逐步走向高潮。罢工运动的次数增多,规模也扩大了。其中影响最大的,是1886年美国芝加哥工人争取八小时工作日的大罢工。”这段话讲的是欧洲各国工运,“其中”举的例子是美国工人大罢工,有将美国说成是欧洲国家之意,故欠严谨。不知可否将“欧洲”改成“欧美”?“欧洲”还是“欧美”?$江苏省泰州市白马桥中学@朱德平$江苏省连云港市中云中学@熊烈$四川省泸县二中@聂华焱 相似文献
5.
《中华人民共和国教育法》第66条在强调规定“县级以上人民政府应当发展卫星电视教育和其他现代化教育手段”的同时,又明确指出:“国家鼓励学校及其他教育机构推广运用现代化教育手段”。显然,这是从我国目前国情的 相似文献
6.
在多媒体技术迅速发展的今天,运用多媒体技术进行教学已经成为潮流,作为一名中学历史老师,如果完全不懂多媒体技术是很难适应时代需要的。笔者经过潜心学习和培训,已初步掌握了一些基本操作,并将掌握的技术应用于教学工作,如运用PowerPoint制作幻灯片进行教学。在PowerPoint课件制作中,表格是一种常用的表现形式。如何让表格动起来,让表格中的内容按制作者的意愿显示出来,是我们遇到的一个难题。通常的做法是在幻 相似文献
7.
课本第82页:“临时政府重新集结力量,向巴黎公社发动进攻,巴黎人民进行了英勇抵抗。5月底,巴黎公社终因寡不敌众,被扼杀在血泊之中。①”同页下注①“参见彩图17”,应为“参见彩图16”。图16为《公社战士就义》,图17为《林肯审阅〈解放黑人奴隶宣言〉》。“图17”应为“图16”$江苏省泰州市白马中学@朱德平$安徽省阜阳市第三中学@叶德季$四川省泸县二中@聂华焱$河南省新乡市第三中学@张金勇 相似文献
8.
本文以“恒成立”题型为例,探究了其不同解法对培养学生思维的严谨性、深刻性、灵活性、创造性的作用,以及对学生抽象思维能力和具体思维能力的培养,达到了优化学生思维品质的目的,为学生的思维提供活力。 相似文献
9.
10.
RH和RH-KTB精炼过程中钢液流动和混合特性的研究 总被引：7，自引：0，他引：7
The flow and mixing characteristics of molten steel during the vacuum circulation refining,including RH(Ruhrstahl-Heraeus) and RH-KTB(Ruhrastahl-Heraeus-Kawasaki top blowing) processes,were investigated on a 1/5 linear scale water model of a 90t multifunction RH degasser,The circulation rate was directly and more accurately determined,using a new method by which the more reliable results can be obtained.The fluid flow pattern and flow field in the ladle were demonstrated,observed and analyzed.The mixing time of liquid in the ladle was measured using electrical conductivity method.The residence time distribution in the RH model was obtained by tracer response technique.The influence of the main technological and geometric factors,including the gas top blowing*(KTB) operation,was examined.The results indicated that the circulation rate of molten steel in the RH degasser can be fairly precisely calculated by the formula:Q1p=0.0333Qg^0.26Du^0.69Dd^0.80(t/min),where Qg-the lifting gas flow rate(NL/min);Du and Dd-the inner diameters of the up and down-snorkels(cm),respectively.The maximum value of circulation rate of molten steel in the case of the 30cm diameters either of the up-and down-snorkels for the RH degasser(the “Saturated” rate) is approximately 31 t/min.the corresponding gas flow rate is 900NL/min.Blowing gas into the vacuum chamber through the top lance like KTB operation does not markedly influence the circulatory flow and mixing charateristics of the RH process under the conditions of the present work.There exist a major loop and a large number of small vortices and eddies in the ladle during the RH refining process.A liquidliquid two-phase flow is formed between the descnding stream from the down-snorkel and the liquid around the stream.All of these flow situation and pattern will strongly influence and determine the mixing and mass transfer in the ladle during the refining.The correlation between the mixing time and the stirring energy density is τmε^0.50 for the RH degasser.The mixing time rapidly shortens with an increase in the lifting gas flowrate.At a same gas flow rate,the mixing times with the up-and down-snorkel diameters either of 6 and 7cm are essentially same.The 30cm diameters either of the up-and down-snorkels for the RH degasser would be reasonalble.The concentration-time curve showed that three circulation cycles are at least needed for complete mixing of the liquid steel in the RH degasser. 相似文献