X-射线衍射仪中样品架对物相分析的影响

由于X-射线衍射分析仪具有操作简单、无损样品、信息全面等优点,是目前进行物相分析的重要方法之一。但在实际操作过程中,样品架自身的衍射信号会影响样品结构的解析,因此X-射线衍射仪中样品架的选择是快速准确得到样品晶体结构及物相分析的关键。该文基于岛津XRD-6100衍射仪,通过对比铝样品架、树脂样品架、无反射样品架、载玻片及自制凹槽样品架,研究样品架对样品衍射信号的影响。结果表明:不同样品架因其性质不同有各自明确的背景峰。若样品量充足,晶型好的样品对于样品架的选择并无特殊的要求,为了得到更高的峰强度,建议使用常规的铝制或树脂样品架;若样品量少且多为非晶态馒头峰的样品,需考虑样品架对其X-射线衍射峰的影响,建议使用无反射样品板,或者以35°为界,特征峰在35°之前建议使用铝制样品架,35°之后建议使用树脂样品架;载玻片和凹槽样品架主要用于特殊形状规格样品的测试。     

Individual participant data meta-analysis of the impact of educational interventions on pupils eligible for Free School Meals

Meta-analysis is the synthesis of findings from research projects, which enables an estimate of the average or pooled effect across various studies. This study presents findings from the intention to treat analysis for a series of educational evaluations in England using a two-stage meta-analysis with standardised outcome data and individual participant data meta-analyses. The research estimates the overall impact of educational trials on pupils eligible for Free School Meals (FSM) and the attainment gap in literacy and mathematics performance between FSM and non-FSM pupils based on analysis of 88 trials and data from over half a million pupils. For the meta-analyses, frequentist and Bayesian multilevel models were used to estimate the individual and pooled effect size across categories of explanatory variables such as age groups (key stages in England) and aspects of the type of interventions (one-to-one, small group, whole class). Results indicated that the overall impact of interventions on the literacy outcomes of FSM pupils was positive, with a pooled effect size of 0.06 (0.03, 0.08). However, for mathematics, no overall effect on FSM pupils was observed. Analysis of the attainment gap indicated that literacy outcomes for FSM pupils were improved by interventions marginally more than for non-FSM pupils (pooled attainment gap 0.01 (−0.01, 0.04)). The risk of bias assessment showed that estimates were consistent across different methodological approaches. Overall, evidence from this study can be used to identify, test and scale educational interventions in schools to improve educational outcomes for disadvantaged pupils.     

Teaching first‐year statistics students with COVID‐19 real‐world data: Graphs

It is said that a picture is worth a thousand words, but what about graphs? Although graphs have the potential to bring data to life, numerous studies show that learners struggle with graphical comprehension. Furthermore, many textbook examples on graphs are boring and appear meaningless to students. Students want to know more about something which is interesting, meaningful, and worth knowing, in other words, something relevant. With the outbreak of the novel coronavirus in December 2019, COVID‐19 is dominating the news worldwide, and the internet is flooded with visual presentations about the virus. To make statistics more fascinating and exciting, relevant and real‐world data such as these can be used in the classroom to stimulate the learning of important statistical concepts such as graphs. Curcio's three levels of graphical comprehension were used as a framework in this study, while the importance of developing a global view on distributions was also emphasized.     

高校数据科学教育生态系统建构——以美国普渡大学为例

作为智能化社会的学科基础要素,大数据正在驱动着高等教育系统的范式变革。美国普渡大学一体化数据科学首倡计划发起的跨学科学术组织变革,强调以跨学科学位项目与学科交叉课程、学科会聚研究计划与研究团队、服务性学习数据社区与主题工作坊、产教融合的数据科学校企合作模式构建高校数据科学教育生态系统。值此加强新时代教育科学研究的战略契机,以"数据+"引导多学科会聚和教育模式创新,打造面向真实世界的数据科学实践社区,建设校企协同产教融合共同体,加快培育大学生数据思维和校园数据文化,将有助于高等教育治理体系改革和治理能力现代化的实现。     

数字图书馆的数据迁移技术

本文简单介绍了当前数字图书馆建设与数据库技术的发展，并着重介绍了数据迁移技术的概念、一般步骤和其实现方法。     

滚齿机床工作台偏差数据采集与补偿系统

本文介绍一种基于PC的数控滚齿机床工作台偏差数据采集与补偿系统。该系统充分利用了一块AC6011数据采集卡实现了多路采集与控制功能,结合PC机强大的数据处理功能与软件的良好支持,实现了智能数据采集与补偿系统的低成本开发。     

论数字图书馆如何实施动态库服务

拟结合相关的软件技术,就网络环境下,现代图书馆向数字图书馆迈进的进程中,如何实施动态库服务问题略抒己见。     

一种有效的数据仓库定制应用方式

本文介绍了如何利用DELPHI中的数据仓库组件开发数据仓库应用系统，为用户提供一种有效的定制的数据仓库应用方式，利用此组件可进行灵活的多维数据分析。     

中国月平均地表反照率的估算及其时空分布

本文利用1948年～2003年55年平均的NCEP/NCAR(National Center for Environmental Prediction/National Center for Atmospheric Research,美国国家环境预报中心/美国国家大气研究中心)再分析辐射资料和中国10km×10km土地利用类型图,借助GIS、GrADS(Grid Analysis and Display System,网格分析与展示系统)等空间化技术,采用图形回归处理等方法建立了国家尺度的10km×10km的中国地表月平均反照率栅格图.研究表明,估算的地表反照率的季节变化十分明显:冬季(1月)最大,夏季(7月)最小,春秋季(4月和10月)次之,且秋季比春季稍大;空间分布与地理纬度、地势高低和距海远近关系很大,西部地区大于东部地区,北部地区大于南部地区,高海拔地区大于丘陵和平原地区.几种土地覆被类型反照率的估计值如下:林地、水稻和小麦地为0.17～0.23;草地为0.20～0.32;雪被为0.44～0.76;沙漠为0.35左右.总的来说,估算结果比较合理,能够较好地反映出中国地表反照率的时间、空间变化特征,也能反映多年气候平均值的特点.因此,在目前气候要素之一的多年平均的地表反照率研究较少的情况下,利用多年平均NCEP/NCAR再分析资料与土地利用类型图进行回归处理不失为是一种相对合理的方法.     

中国SCI论文数据分析与思考

追溯中国(含台湾)SCI论文发展的历程,对中国SCI论文的产出、引用、所有涉及学科现状及各省级行政区SCI论文发表情况等进行剖析,得出以下主要结论:(1)我国SCI论文在经历了高速增长后,目前已经进入平缓发展阶段;(2)我国已成为SCI产出大国,涌现出了很多高质量论文,但论文总体质量偏低;(3)中国大陆不同区域人均SCI论文产出以及单位GDP产生的论文数量存在不平衡性。对所得出的相关结论进行思考和探讨。