Variability in children’s early reading strategies

The present study examines the development of sight word reading in young children by examining changes in their self‐reported reading strategies over time. A sample of 65 five to seven year olds were asked to read 40 real word items, all carefully matched for letter length and word frequency, on three separate occasions. Changes in the children’s word identifications were measured using immediately retrospective verbal self‐reports. Overall, the results showed some variability in the children’s self‐reported reading strategies. Over time the children relied less on phonological strategies and moved towards reliance on directly retrieving words from memory. This change was most evident in the older children; while both year groups showed similar patterns of shifting reliance from explicit phonological strategies to retrieval, this shift was simply less frequent among the younger children. An analysis of word‐specific changes in reading strategies showed that the older children had a better sight vocabulary for more complex word items. These findings provide further support for Ehri’s mediated phase theory in explaining children’s development in learning to read.     

Pre-kindergarten teachers’ use of transition practices and children's adjustment to kindergarten

This study describes pre-kindergarten teachers’ use of kindergarten transition practices and examined the extent to which these practices were associated with kindergarten teachers’ judgments of children's social, self-regulatory, and academic skills upon their entry into kindergarten. Participants were 722 children from 214 pre-kindergarten classrooms participating in the National Center for Early Development and Learning's (NCEDL) Multi-State Pre-kindergarten Study. Of nine transition practices intended to promote children's adaptation to kindergarten, pre-kindergarten teachers reported implementing, on average, six transition practices, with notable variation across pre-kindergarten classrooms. Children were judged by their kindergarten teachers to have more positive social competencies and fewer problem behaviors when they attended pre-kindergarten classrooms in which more transition activities were implemented and, specifically, in which teachers discussed curricula or specific children with kindergarten teachers. In addition, positive associations between kindergarten teachers’ perceptions of children's social competence and pre-kindergarten transition activities (total number of activities and activities that children experience directly) were stronger for children who experienced social and economic risks. Implications of these findings related to alignment across the pre-kindergarten to kindergarten settings to improve children's school readiness are discussed.     

锂离子电池正极材料LiNi0.8Co0.2O2的研制

采用热分析法对不同组成的LiOH-LiNO3二元体系进行研究,绘制了具有最低共熔点的该二元体系T-x相图。用该低共熔混合物为锂盐,与前驱体Ni0.8Co0.2(OH)2混合烧结制备出锂离子电池正极材料LiNi0.8Co0.2O2。     

高温相变材料在重力热管外表面凝固的偶合计算

利用高温相变材料储热，同时用重力热管作为能量传输元件这一高效偶合装置在生产和生活中有广阔的应用前景。本文在实验基础上建立一个考虑自然对流影响的相变传热与热管传热相偶合的传热模型，并对该模型进行数值计算，通过与实验结果进行的对比，证实所建立的模型与所采用的计算方法均是合理可行的。     

Orign7.0在科技绘图、数据处理方面的应用

Origin7.0是当今世界上最著名的科技绘图和数据处理软件之一.本文详细研究了目前国内应用Origin软件进行实验数据处理方面的进展情况,又研究了曲线拟合后,作某点切线和求该点切线斜率的方法、三角坐标纸的制作及三组分相图的绘制等新的应用.     

相位模板技术与布拉格光纤光栅的写入

由于相位模板法仅使用一个光学器件 ,因而减少了光纤光栅制造系统的复杂性 ,是光纤布拉格光栅写入法中最有前途、使用最广泛并且具有本征稳定性的一种方法 .本文总结了相位模板技术及各种光纤布拉格光栅的写入 .值得注意的是在相位干涉法中 ,只用一块相位模板 ,就可以调整写入光纤布拉格光栅的波长 .在这些系统中 ,写入光纤光栅的紫外线 ( UV )干涉条纹经由一些光学元件 ,其中 ,相位模板的作用通常是± 1级衍射光的分束器     

含有DM相互作用的混合XXZ模型的临界性质

利用平均场近似的方法,研究了立方晶格上具有DM相互作用的混合XXZ模型的相变和临界性质.在Ising极限下,在不同的DM相互作用参量D下做出了系统的自发磁化强度m随约化温度T=1/K的变化,得到了系统的临界温度,分析了DM相互作用对系统临界温度的影响;在不同的各向异性参数△下作出了系统二级相变线,结果表明混合自旋XXZ系统只存在二级相变,系统没有出现三临界点.     

论大众化阶段精英高等教育存在与发展的必然性及合理性

目前,我国高等教育发展已经进入大众化阶段,在高等教育多样化发展格局中,精英高等教育作为整个高等教育体系的一部分,标志着高等教育发展的质量与水平.在分析大众化阶段精英高等教育的内涵及精英高等教育存在与发展的必然性与合理性的基础上,提出了相应的发展策略.     

邻苯二甲酸丁基苄基酯C18萃取条件的优化

一种环境友好样品处理技术———固相萃取技术被用于环境激素类物质邻苯二甲酸丁基苄基酯(BBP)痕量检测研究中。利用GC-ECD进行检测,借助于均匀设计法合理安排试验,通过计算机回归技术对C18固相萃取柱的萃取条件进行设计和优化,建立了相关的数学模型,找出了各因素对峰面积的影响规律。成功地确定优化的BBP固相萃取条件为:正己烷与丙酮配比30∶1、洗脱体积2.0ml、洗脱速率4.0ml/min、上样速率8.0ml/min。     

基于遗传算法的阵列相位误差校正

针对声纳水听器阵列比较突出的相位误差,研究了一种基于遗传算法的阵列校正方法。该方法利用无相位误差时阵列协方差矩阵具有Toeplitz结构的特性构造代价函数,并以此作为遗传算法中进化个体的适应度函数,由算法搜索的最优个体得到阵元相位误差的估值。计算机仿真结果表明,该方法可以明显地减小阵列相位误差对MUSIC算法DOA估计结果的影响。