共查询到19条相似文献，搜索用时 453 毫秒
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借助于数值分析软件MATLAB,利用传输线理论对二平行印制线间的串扰耦合进行分析,得出耦合响应与传输线参数的定量关系,给出电子电路设计中PCB印制线布设的原则. 相似文献
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向丽 《绵阳师范学院学报》2007,26(12):113-115
感光材料是伴随着摄影技术的产生而出现的。传统摄影在经历了从黑白感光材料到彩色感光材料的发展历程后,已被认为是进入了"彩色时代"。从摄影整体看,拍摄彩色片已占80%以上。彩色感光材料的种类繁多,本论文主要是对彩色摄影感光材料中的彩色负片和银漂法彩色感光材料的性能特点进行重点分析和比较,从而使摄影者对这两类彩色感光材料有更理性的了解和认识。 相似文献
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邹显圣 《中国现代教育装备》2009,(17)
总结了多年从事Protel 99 SE课程教学过程中的技巧与经验,选取了学生制作PCB的实例;分析了PCB中产生常见错误的原因;提出了基于Net属性的PCB在线修改技术;给出了PCB中在线修改错误的具体步骤.通过使用适当的PCB在线修改技巧、借鉴有效的经验,可以在很大程度上提高PCB的制作速度和质量、杜绝由于电气原理图设计过程不正确所带来的一系列问题. 相似文献
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当前的情感教育有趋于＂单向度＂的倾向,这集中表现在它过度关注学生的正性情感发展,忽视了学生的负性情感发展。情感教育要关注学生的负性情感发展,其基本缘由是因为学生的情感既有正性性质的,也有负性性质的。深层的缘由则在于学生的某些不良行为是植根于负性情感的,而要从根本上摈弃这种不良行为就必然要对学生的负性情感进行教育上的干预。在关注学生的负性情感时,教师应做到：要懂得如何识别负性情感;要允许学生表现或宣泄内心的负性情感;要对学生的负性情感进行有针对性的教育干预。 相似文献
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介绍用Altium公司的Altium Designer Winter09软件完成印刷电路板（PCB）的三维（3D）显示;PCB板的三维设计;导入STEP Model形成三维模型;将PCB板的3D文件导出到MCAD软件。以提前预知印刷电路板设计的合理性,缩短新产品的开发周期,便于设计部门与制造部门进行良好的沟通。 相似文献
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从经济管理领域引入价值分析的方法解读群体泄愤事件。首先,分析了价值分析方法引入的可行性,提出负性价值分析的概念;其次,分析了负性价值分析的各个要素;再次,分析了负性价值追求的主要途径。在分析的基础上,构建了一个群体泄愤事件负性价值分析的框架,得到几点理论启示。 相似文献
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坐落在古城保定的乐凯胶片公司是中国自行研制开发的彩色胶卷的诞生地。它是一个以生产民用照相材料、电影胶片、航空航天胶片等产品为主的大型国有企业，“一五”期间国家重点建设项目。经过30多年的建设与发展，已成为我国技术力量最强、产量最大、品种最多、市场覆盖面最广的综合性感光材料科研与生产基地。乐凯作为国内唯一的大型彩卷生产厂家，肩负着振兴民族感光材料工业的重任。·今天乐凯虽然与诸多国有企业一样，面临着外国跨国公司进逼的严峻局面，然而乐凯立足于拼搏，激流勇进，与外国大公司展开了事关民族感光材料工业兴衰的较… 相似文献
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喷纳线路板是一种零污染、零排放、全数字加工的线路板.不用覆铜板、不用腐蚀、不用水、不用感光显影、不用制网版就能将导电线路制作在树脂板、塑胶板、玻璃板、陶瓷板和PET、PI薄膜等绝缘材质上.经电路实测应用,完全达到使用标准.只需将CAD线路图输入线路板喷纳机,即可加工出线路板.非常适合电路实训,线路板设计制作现场演示教学,满足高新技术企业和科研机构对线路板快新奇特的要求.是线路连接领域的技术突破. 相似文献
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许霆 《常熟理工学院学报》2000,14(1):1-3
这是世纪之交对中国现代文学研究回顾和展望的笔谈。文章以这门学科在本世纪使用的三个概念作为线索,概括了这门学科在艰难曲折中发展的历程;文章由这门学科发展现状,即研究空间、研究时间、研究方法、研究途径的拓展,学术规范的建设,指明面向新世纪的中国现代文学研究这一学科正在走向成熟。 相似文献
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Alan Zaring 《Computer Science Education》2013,23(2):135-163
This paper presents CCL, a programming language designed for implementation efforts and laboratory projects in compilers courses for undergraduates. CCL is small, cohesive, and regular enough that a working compiler can be implemented by an individual student in a single semester; yet, CCL includes a collection of features (including pointers, dynamically-sized arrays, anonymous functions, and a restricted form of continuations) that make it a useful vehicle for studying compiler theory and design. Experiences using CCL in compilers courses are discussed, and suggestions for a number of projects concerning CCL are given. 相似文献
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Rapid advances in technology, particularly with the Internet, have led to the availability of numerous tools to support teaching
and learning. This study involved the use of an Internet application, Connecting Communities of Learners (CCL), in courses
for prospective teachers. Unlike earlier studies involving the use of the CCL, the context of this study related to full-time
graduate students who used the CCL to augment weekly face-to-face instruction. An interpretive study was undertaken to ascertain
student and teacher perceptions of the learning environments associated with the use of the CCL. Through the use of the CCL,
students were able to be autonomous in regard to their own learning, co-participate with their peers and the instructor, and
establish and maintain a community of learners in which participants could interact with others as co-teachers and co-learners.
The CCL was perceived as a useful tool for building learning environments in which all participants can contribute written
texts as evidence of what is known and as objects from which others can learn.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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从生物学角度上对竹红菌甲素(HA)光敏活性进行了研究，运用MTT法实验发现HA合并光照处理人黑色素瘤B-t6细胞，HA对B-16细胞具有明显的杀伤作用，使癌细胞存活率显著下降，结果表明HA具有光敏抗癌活性。 相似文献
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The case‐based computerized laboratory (CCL) is a chemistry learning environment that integrates computerized experiments with emphasis on scientific inquiry and comprehension of case studies. The research objective was to investigate chemical understanding and graphing skills of high school honors students via bidirectional visual and textual representations in the CCL learning environment. The research population of our 3‐year study consisted of 857 chemistry 12th grade honors students from a variety of high schools in Israel. Pre‐ and postcase‐based questionnaires were used to assess students' graphing and chemical understanding–retention skills. We found that students in the CCL learning environment significantly improved their graphing skills and chemical understanding–retention in the post‐ with respect to the prequestionnaires. Comparing the experimental students to their non‐CCL control peers has shown that CCL students had an advantage in graphing skills. The CCL contribution was most noticeable for experimental students of relatively low academic level who benefit the most from the combination of visual and textual representations. Our findings emphasize the educational value of combining the case‐based method with computerized laboratories for enhancing students' chemistry understanding and graphing skills, and for developing their ability to bidirectionally transfer between textual and visual representations. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 219–250, 2008. 相似文献
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电影《危险关系》是一部以男性与女性的关系意象为主要叙事对象的作品,在男权叙事下演绎了两性之间看与被看、控制与反抗、霸权与妥协的复杂关系。它在男性凝视中建构诱惑的女性身体、叙述潜在的女性缺陷,以此对男性性欲与权欲进行二维迎合;它在性别标记下展示女性的逆动与反抗状态,从而表达其企图挣脱男权牢笼的强烈祈愿与女性意识;它最终以三种殊途同归的"寡妇"形象书写了女性败北妥协的悲剧命运。在此动态的逻辑层面上,电影揭示出男权藩篱圈禁下女性无法规避的"被看——反抗——妥协"的现实生存困境。 相似文献