电路板ENEPIG表面涂覆工艺实验

在ENEPIG表面涂覆新工艺中引入了化学镀钯层,从反应原理上杜绝了镀镍层的氧化,在化学镀金过程中阻挡了镀镍层与浸金溶液的接触、镍的扩散和迁移,从而有效地抑制镍表层的氧化,防止"黑垫"缺陷产生。给出了该工艺量产的流程及参数控制,运用SEM和EDS对产品进行了微观形貌及扩散性分析。结果发现,钯层是非结晶状的皮膜,具有很好的镀层厚度均一性,并且在金表面没有发现镍的扩散。从而成功地实现了ENEPIG电路板的量产,替代了ENIG工艺。     

浅析化学工艺镀层在非金属表面的应用

在生活中我们接触到的物品中,很多物品都是在非金属表面镀镍工艺.本文在传统的工艺的基础上介绍了一种非金属表面化学镀镍无钯活化工艺,希望能相互交流,确保这种工艺的可持续性发展.     

浅谈林化分析与工艺实验教学中的设计性实验

阐述了“设计性”实验教学对培养学生分析问题和解决问题能力的作用,强调了在“设计性”实验教学中应注意的5个环节,同时讨论了这种教学形式对提高教师业务水平和教学水平的意义。     

生物工艺综合性实验的实践与体会

生物工艺综合性实验在生物工程专业学习中有十分重要的地位,本文探讨了实验教学改革的实施及应该注意的环节.实践证明生物工艺综合实验的开设,能够弥补传统的验证性实验项目的不足和提高学生分析与解决问题的能力,是实验教学改革的一个方向.     

化学实验的绿色化

化学研究中不可避免地要做化学实验,传统的实验模式往往伴随着高污染和高消耗。随着时代的发展,那种具有高污染和高消耗的传统实验方式已经不能适应要求。为了适应时代的发展变化,我国提出了"绿色化学"的口号。我国化工事业在学习西方先进技术的同时,对自身的化学工艺也进行了一定的改进。     

《电器可靠性技术》开设实验课程的研究

学校根据低压电器企业对人才的需求,调整《电器可靠性技术》课程的教学方式,开设实验课,以增强学生的实际动手能力和创新能力,使学生掌握四种低压电器可靠性实验的方法,以实现毕业后能尽快就业这一目标。     

制备乙酸乙酯的实验分析

乙酸乙酯的制备实验是中学化学实验中的重要内容，它在化学新教材(人教版)上作为教学内容重点讲述过，又安排了学生实验，让学生走进实验室亲自动手制备过，以下是考查这个实验内容的习题，不知同学们有怎样的感觉，能从中得到什么启示，做完这道题后，再回过头去看教材，又有什么样的思考和收获，这个问题就留给同学们自己去完成。     

刍议计算机网络可靠性分析与设计

随着社会的发展,人们使用计算机的次数在逐渐增加,信息化时代理念广泛地渗透到社会生活的方方面面。人们对计算机网络安全有了更高要求,同时也就需要对用户使用的质量有所保证,需要提高计算机网络的质量水平。计算机网络的可靠性是网络服务质量的重要衡量指标,对于网络可靠性的研究也得到了学者广泛的重视。     

对化学教材实验与高考实验考查的思考——兼谈制备乙酸乙酯的实验分析

在化学教材上安排了不少的实验内容，有教师演示实验，有学生实验，在高三化学新教材上还专门安排了第六单元化学实验方案的设计，足见实验内容的重要性。怎样才能有效地复习好化学实验内容，是一个值得探讨的课题。本文以乙酸乙酯的制备为例，谈点粗浅的看法，供参考，旨在抛砖引玉。     

基于响应面法的钢拱桥可靠度分析

大型复杂桥梁结构的极限状态函数都是隐式的非线性函数,采用传统的可靠性分析方法可能无法实现,但利用响应面有限元法可以很好地解决这类问题。利用响应面法对一下承式钢拱桥拱肋、主梁在正常使用极限状态下的轴向应力、竖向位移的可靠度进行了分析,并根据拟合出的各极限状态函数显式表达式得出了相应的可靠度指标,说明响应面有限元法是计算下承式钢拱桥构件可靠度的有效方法。     

桁架可靠性分析的分支-界限分析法

从事件的追踪分析出发,用分支－界限法对桁架系统进行了可靠性分析,分析过程直观、明了,适合对实际工程中的桁架结构进行可靠性分析．     

螺旋机构的静动态精度可靠性分析

考虑螺旋机构的各项原始误差和物理参数的随机性,对其静态误差和动态误差逐项进行了分析,利用微小位移的线性叠加原理对静态、动态误差进行了综合,在此基础上建立了机构运动精度可靠性分析模型.通过算例,考察了各随机变量对螺旋机构运动精度可靠度的影响,并获得了一些有意义的结论.     

试验设计在实验设备可靠性分析中的应用

为了掌握实验设备的运行质量状况,从质量管理的角度出发,提出把实验设备纳入测量系统范畴的试验设计(DOE)方法。根据DOE的原理,在测量系统中用统计方法设计试验,采集、分析响应数据,确定测量系统的显著影响因素,从而对实验设备进行可靠性分析。采用DOE分析传感器测量系统可靠性的实例表明,DOE能够以相对少的实验运行次数,最大化掌握测量系统的有用信息,找出测量系统可靠运行的最佳状态,是高校实验设备可靠性分析的一种实用方法。     

响应面法优化甘薯茎叶中黄酮类化合物的提取工艺

为优化甘薯茎叶中黄酮类化合物的超声提取工艺,在单因素实验的基础上,选择乙醇浓度、溶剂倍量、超声提取时间为自变量,黄酮得率为响应值,采用Box-Behnken组合设计,运用Design-Export 8.05b软件分析各自变量及其交互作用对黄酮得率的影响,建立了黄酮得率的二次多项式回归方程的预测模型。确定甘薯茎叶中黄酮的最佳提取工艺条件为:乙醇浓度60.00%、溶剂倍量35.00、超声时间40.00min,在此条件下,黄酮得率为10.3002%。本研究原料价廉易得,提取方法高效可行,分析方法可信,可为甘薯茎叶的开发利用提供依据。     

Validity and Reliability of a Shortened,Revised Version of the Constructivist Learning Environment Survey (CLES)

The purpose of the study was to investigate the use of an existing instrument, the Constructivist Learning Environment Survey (CLES)(Taylor, Dawson & Fraser, 1995; Taylor, Fraser & Fisher, 1993, 1997), for providing insights into the classroom learning environments of beginning science teachers. In the first year of the study, the CLES was used with 290 upper elementary, middle, and high school science teachers and preservice teachers. As part of a larger study of the classroom environments and teaching practices of beginning science teachers, data also were gathered through classroom observations of and interviews with some of the participating teachers. Exploratory factor analysis and internal consistency reliability analysis, as well as examination of each item and of participants' questions and comments about them, led to a shortened, revised version of the CLES, named the CLES 2(20). The five original scales were retained, but the number of items in each scale was reduced from six to four. The single negatively worded item was eliminated. Some of the original items were rephrased. The revised CLES was then used in the second, third and fourth years of the study. Examples of feedback based on CLES data is provided to researchers to assist them in writing teacher profiles.     

The Delphi Technique in Identifying Learning Objectives for the Development of Science,Technology and Society Modules for Palestinian Ninth Grade Science Curriculum

This article outlines how learning objectives based upon science, technology and society (STS) elements for Palestinian ninth grade science textbooks were identified, which was part of a bigger study to establish an STS foundation in the ninth grade science curriculum in Palestine. First, an initial list of STS elements was determined. Second, using this list, ninth grade science textbooks and curriculum document contents were analyzed. Third, based on this content analysis, a possible list of 71 learning objectives for the integration of STS elements was prepared. This list of learning objectives was refined by using a two-round Delphi technique. The Delphi study was used to rate and to determine the consensus regarding which items (i.e. learning objectives for STS in the ninth grade science textbooks in Palestine) are to be accepted for inclusion. The results revealed that of the initial 71 objectives in round one, 59 objectives within round two had a mean score of 5.683 or higher, which indicated that the learning objectives could be included in the development of STS modules for ninth grade science in Palestine.     

Teacher Education and the Integration of Technology: a reading and language arts perspective

ABSTRACT

Teachers are increasingly expected to employ integrated technology practices in their classrooms to help students learn more, better, faster and cheaper. Unfortunately, teachers generally have not been provided education or training on how to employ these technology practices. Attempting to get integrated technology practices into pre‐service and in‐service teacher education, especially in reading and language arts, is at the core of this article. An overview of technology integration is provided along with discussions about: (a) goals and content for teacher education courses or training, (b) research on integrating technology into reading and language arts education, (c) integration without education and training, and finally (d) issues that affect integration.