尼龙6、尼龙66/粘土纳米复合材料的制备和性能

文章综合近年来国内外关于尼龙/粘土纳米复合材料的文献,详细论述了尼龙/粘土纳米复合材料的制备方法和性能。     

An Historical Phenomenology of Mean and Median

Using Freudenthal’s method of historical phenomenology, the history of statistics was investigated as a source of inspiration for instructional design. Based on systematically selected historical examples, hypotheses were formulated about how students could be supported in learning to reason with particular statistical concepts and graphs. Such a historical study helped to distinguish different aspects and levels of understanding of concepts and helped us as instructional designers to look through the eyes of students. In this paper, we focus on an historical phenomenology of mean and median, and give examples of how hypotheses stemming from the historical phenomenology led to the design of instructional activities used for teaching experiments in grades 7 and 8 (12–14-years old).     

“Too many theories and not enough instruction”: perceptions of preservice teacher preparation for literacy teaching in Australian schools

In this paper, we describe part of an Australian national research project that aimed to find out how well prepared beginning teachers are to teach literacy. A majority of beginning teachers participating in a series of national surveys and focus group meetings were confident about their personal literacy skills, their conceptual understandings of literacy, their understanding of curriculum documents and assessment strategies and their broad preparation to teach. Fewer beginning teachers were confident about their capacity to teach specific aspects of literacy such as viewing, spelling, grammar and phonics, or about their capacity to meet the challenges of student diversity. Senior staff working with beginning teachers were generally sceptical about the quality of teacher preparation for teaching literacy and were less confident than the beginning teachers about personal literacy skills. We discuss these findings in relation to the relative importance placed on particular substantive and structural issues by the study participants and in terms of previous findings.     

磁性纳米材料的制备及应用新进展

综述了磁性纳米材料的制备方法,如机械球磨法、水热法、微乳液法、超声波法等,归纳了各种制备方法的优缺点.对磁性纳米材料当前的应用热点进行了概述,并对其研究前景进行了展望.     

死髓牙根管治疗诊间急症的临床观察和分析

目的探讨死髓牙根管治疗诊间急症(IAE)发生的临床相关因素.方法对101例临床病人103颗根管治疗的死髓牙进行临床观察.结果 27颗牙(26.21%)发生了IEA,其中后牙IAE的发生率高于前牙.结论根管预备时,对不同牙位在IAE发生中的特点应予以重视.     

Exploring the Borderlands: Elementary School Teachers’ Navigation of Immigration Practices in a New Latino Diaspora Community

Drawing primarily on interview data from a 5-year ethnography on the school experiences of Mexican immigrant children in a New Latino Diaspora community, we explore how their teachers understood and responded to increasing deportation-based immigration practices affecting children’s lives. We illustrate how teachers fell along a continuum regarding their desire and success in pushing beyond their comfort zones to create spaces in which they learned from, and built on, students’ immigration experiences. We argue for teacher education that prepares educators to become border crossers who engage with aspects of difference, such as immigration status, that are rarely discussed in schools.     

非晶颗粒态木薯淀粉制备方法研究

系统地报道了水分散体系高温溶胀、常温碱分散体系强碱溶胀作用非晶颗粒态木薯淀粉制备方法．采用偏光显微镜对多晶态向非晶态的变化进行了确认，提出在一定条件下，高交联木薯淀粉可以由原淀粉多晶颗粒态制备成只含无定形结构的非晶颗粒态淀粉．     

半导体激光器发射光谱实验分析

文章分析了半导体激光器发射的荧光光谱、激光光谱 ,解释了光栅外腔选取单纵模、压窄线宽、波长调谐的机理     

A completely open cavity realized with photonic crystal wedges

A left-handed (LH) material (also called a nega-tive refraction index material) exhibiting a negativerefraction index due to simultaneously negative per-meability and permittivity, was first introduced byVeselago in 1967 (Veselago, 1968). Negative refrac-tion has recently attracted much attention in thephysics and electrical community engineering due toits potential impacts and applications (Shelby et al.,2001; Pendry, 2000). Negative refraction can also beachieved in some negative refractio…     

用腔QED技术实现纠缠交换

基于腔QED系统,提出一种纠缠交换的方案,不仅能实现没有直接相互作用的原子不同程度的纠缠,还能实现未知纠缠状态转移到没有直接相互作用的原子上去.在此方案中只对原子做独立测量,没有使用联合测量,原子跃迁频率与场模频率大失谐,场只是虚激发,腔场品质因子的要求比共振条件下大大降低.