耐水和低游离甲醛脲醛树脂的合成与改性

为寻求合适的工艺条件以提高脲醛树脂胶粘剂的综合性能,采用了降低甲醛/尿素物质的量比、改进合成工艺、加入改性剂等3种途径优化了脲醛树脂的合成方法.实验结果表明:以甲醛和尿素为单体,添加适量的聚乙烯醇和三聚氰胺改性剂,甲醛和尿素最佳物质的量比约为1.5:1,尿素分3次(11.4 g、0.5 g、0.2 g)投料,反应温度控制在(35℃-85℃),反应时间约60min,用聚乙烯醇和三聚氰胺进行改性,可制得综合性能较好的低毒耐水脲醛树脂胶粘剂.产品质量达到国家相关规定指标.     

改性脲醛树脂胶的研究

本文主要阐述降低脲醛树脂胶中游离甲醛含量的方法。如降低原料配方摩尔比,采用多次投料,使用甲醛捕捉剂等。     

关于合成脲醛树脂最佳投料比的实验探讨

就脲醛树脂的投料比,以及分批加入尿素进行了实验探讨,得出最佳投料比。     

刨花板用脲醛树脂改性方法的研究

本丈针对木材用脲醛树脂胶耐水、耐热性差、游离甲醛含量高等缺点，研究了脲醛树脂的改性方法，通过降低尿素与甲醛的摩尔比、改变投料方式、加入改性组分等方法可获得性能优良的改性脲醛树脂。     

固化的脲醛树脂水解稳定性的研究

通过一种脲醛树脂水解稳定性检测方法的建立,模拟在热压条件下,脲醛树脂在不同反应条件下水解稳定性的变化。实验表明,相同的pH值下,树脂水解稳定性随树脂含水率的提高而下降;相同含水率下,树脂水解稳定性随PH值下降而下降。     

培养学生核心素养的有机化合物教学——以“甲醛的性质与应用”为例

选择甲醛为核心物质,根据其结构特征建构碳氧双键与极性键加成反应的模型;在分析甲醛制备脲醛树脂过程中应用模型,并从化学键的断裂和形成角度分析其形成过程,概括有机反应的特征与规律;在分析福尔马林防腐原理时巩固模型、强化有机反应规律;并进一步利用其结构和性质分析检测甲醛浓度和降低甲醛浓度的方法,发展模型。     

室内装饰材料中甲醛含量的测定

利用二乙酰基二氢二甲基吡啶（DDL）在412nm处具有最大吸光度,运用汉茨（Hantzsch）反应对甲醛所表现出来的良好特性,采用气体分析法测定样品中甲醛的含量进而分析新装修后居室的污染情况,结果表明,气体分析法是一种快速便捷的测定新装修后居室的甲醛含量的方法,其灵敏度高.     

脲醛树脂合成实验中应注意的几个问题

本文对脲醛树脂合成过程的条件、参数进行了摸索，得出了与实验教材中的表述有所不同的结论。提出了温度、pH检测、终点检测和迅速冷却是实验成败的关键问题，并做了较详尽的描述。     

酸度计法测定水发食品中甲醛的含量

对酸度计法测定水发食品中的甲醛进行了研究,探讨了该方法的实验条件及干扰因素。在优化的实验条件下,测得样品加标回收率为92.7%-102.5%,相对标准偏差为6.6%。该方法使用仪器简单、操作方便、选择性和准确度好,适合水发食品中甲醛含量的测定。     

低毒脲醛树脂黏合剂的研究

本文介绍了含游离甲醛低、黏结强度大的建筑行业用脲醛树脂黏合剂的制备方法 .研究了树脂合成过程中原材料纯度、尿素和甲醛的摩尔比、反应温度以及反应时间等对黏度和固含量等性能的影响 .在一定酸度和温度条件下 ,分批加入尿素进行阶段反应 ,得到一种胶液性能稳定、黏结强度高的建筑板材用黏合剂 .     

pH值对脲醛树脂胶贮存稳定性影响的实验研究

对脲醛树脂胶的贮存稳定性随pH值的变化进行研究,以指导生产,提高产品的适用性.     

The Case Anatomical Knowledge Index (CAKI): A novel method used to assess anatomy content in clinical cases

There are concerns in the literature that the use of case‐based teaching of anatomy could be compromising the depth and scope of anatomy learned by students in a problem‐based learning curriculum. Poor selection of clinical cases that are used as vehicles for teaching/learning anatomy may be the root problem because some clinical cases do not provide enough opportunities to learn anatomy and are, therefore, inappropriate for case‐based teaching. Although anatomy educators are expected to respond to the identified deficiencies of case‐based anatomy teaching, making sure that students acquire sufficient anatomical knowledge to practice safely and successfully, there are no tools available that can help improve the selection of clinical cases for case‐based teaching. The author proposes a composite index, which incorporates considerations of anatomical knowledge for evaluating clinical cases/conditions for suitability in case‐based anatomy teaching. The development of the case anatomical knowledge index (CAKI) using a modified Guttman procedure is described. The scalability of the index was measured using the coefficient of reproducibility. A total of 47 clinicians participated in the validation activities that measured interrater and intraclass reliability. The CAKI was able to consistently discriminate between clinical cases/conditions with higher demand for anatomical knowledge than those with lower demand for anatomical knowledge. A review of the literature suggests that such an index has not been previously reported. Given the concerns about the depth and scope of anatomy learning in case‐based teaching, these findings have international relevance. Anat Sci Ed 2:9–18, 2009. © 2009 American Association of Anatomists.     

A systematic review of randomized controlled trials of interventions designed to decrease child abuse in high-risk families

Child abuse is a global problem, and parents with histories of childhood abuse are at increased risk of abusing their offspring. The objective of this systematic review is to provide a clear overview of the existing literature of randomized controlled trials evaluating the effectiveness of interventions to prevent child abuse. PubMed, PsychINFO, Web of Science, Sociological Abstracts, and CINAHL were systematically searched and expanded by hand search. This review includes all randomized controlled trials (RCTs) of interventions designed to prevent abuse among mothers identified as high-risk. Of the eight studies identified, only three found statistically significant reductions in abuse by any measure, and only two found reductions in incidents reported to child protective services. While much has been written about child abuse in high-risk families, few RCTs have been performed. Only home visitation has a significant evidence base for reducing child abuse, and the findings vary considerably. Also, data from low- and middle-income countries are limited.     

Mindfulness-based meditation to decrease stress and anxiety in college students: A narrative synthesis of the research

ObjectiveThe primary purpose of this paper was to narratively review the research testing the effects of mindfulness meditation on stress and anxiety in the college students; reviewing the inclusion of mindfulness was a secondary purpose.MethodsA literature search resulted in 57 studies on the effectiveness of mindfulness meditation in reducing stress and anxiety in college students.ConclusionsResearchers examined anxiety in 40 studies, self-reported stress in 34, physiological stress in 11, and mindfulness in 24. Thirty-three of 40 and 25 of 34 studies showed significant decreases in anxiety and stress respectively; 22 of 24 showed an increase in mindfulness. Physiological stress had inconsistent results indicating a need for further research. Overall, mindfulness meditation shows promise in reducing stress and anxiety in college students. Additionally, there are a number of differences in mindfulness interventions including frequency, duration, instructional method, and inclusion of yoga, that need quantitative examination (meta-analysis) to determine which is most effective.     

临沂市水资源承载力及其提升措施研究

随着城市建设、工农业生产的迅速发展,临沂市水资源越来越显得短缺,水资源供需关系日趋紧张．水资源承载力严重不足,并在一定程度上成为临沂市国民经济建设和社会可持续发展的重要制约因素。提高临沂市水资源承载力,必须建立科学的水资源管理体系,调整产业结构,加强水资源优化配置,促进社会经济、资源环境可持续发展,加大水资源保护工作力度,通过价格杠杆提高水资源的承载能力。     

西部地区人力资源开发对策探析

西部大开发，主要是开发两方面的资源：一方面是物质资源，另一方面是人力资源。其中，人力资源的开发为物质资源的开发提供人力和智力支持，是物质资源得到全面，高效、合理开发的重要前提。人力资源不同于物质资源的特性，决定了人力资源素质的高低对经济发展所产生的决定性影响。本拟在人力资源开发的重要性和紧迫性的基础上，对人力资源开发的对策进行探讨，以期引起人们对这方面同题的关注。     

Research Trends in Science Education from 2008 to 2012: A systematic content analysis of publications in selected journals

This paper presents the third study of research trends in science education. In this review, a total of 990 papers published in the International Journal of Science Education, the Journal of Research in Science Teaching, and Science Education from 2008 to 2012 were analyzed. The results indicate that in the recent five years (2008–2012), the top three research topics in the published papers were those regarding the context of students' learning, science teaching, and students' conceptual learning. The changes in the most popular research topics in the past 15 years also evidentially indicate shifts in the journals' preferences and researchers' interest. For example, in 2003–2007, context of students' learning replaced students' conceptual learning, which was the most published research topic from 1998 to 2002. The research topic of students' learning contexts continued to rank the first in 2008–2012. Moreover, there was an increasing trend of research papers regarding science teaching from 1998 to 2012. The analysis of highly cited papers revealed that research topics such as argumentation, inquiry-based learning, and scientific modeling were recently highlighted by science educators. In recent 15 years, productive researchers' publications also focused on the topics about context of students' learning, science teaching, and students' conceptual learning.     

Infusing higher-order thinking and learning to learn into content instruction: A case study of secondary computing studies in Scotland

This case study examines ideas on a thinking curriculum and learning to learn in the context of secondary education, by exploring one subject area- computing studies- at the Scottish secondary 3/4 (S3/S4) level with 14- to 16-year-olds. The infusion approach used in this project combines direct teaching on problem solving strategies, modeling of solution processes, on-going formative assessment, and developing metacognition through processes of reflection, articulation and exploration. The case study provides an example of how these approaches can be interweaved within a problem-based learning methodology for teaching computer programming at an introductory level. The study demonstrates how an appropriate balance can be struck between content objectives and broader educational goals within an infusion approach, resulting in the achievement of successful learning outcomes. Extending the approach to other subject domains could greatly enhance the connectedness of the secondary curriculum, thus enabling students to learn more efficiently. This would require cross-curricular collaborations and a reformulation of existing curricula.     

高职英语人才培养模式的构思及课程体系改革

在高职教育中，改革传统的教学模式，培养在知识结构，能力结构，素质结构等方面适应社会主义经济发展所需要的高等技术应用性人才已成为当务之急，中阐述了高职英语人才培养目标的定位，知识，能力，素质之间的关系，树立终身教育，终生学习和建立学习化社会的新观念及其教学体系改革的一些方法。     

A novel patchwork model used in lecture and laboratory to teach the three‐dimensional organization of mesenteries

Anatomy teaching is seeing a decline in both lecture and laboratory hours across many medical schools in North America. New strategies are therefore needed to not only make anatomy teaching more clinically integrated, but also to implement new interactive teaching techniques to help students more efficiently grasp the complex organization of the human body. Among the difficult anatomical concepts that students struggle to understand, the anatomy of the peritoneal cavity with its complex projections of peritoneum could benefit strongly from new learning aids. In this report, an innovative teaching tool is presented to engage students during both lecture and laboratory, and help them build three‐dimensional (3D) mental maps of peritoneal cavity. The model consists of a patchwork of mesenteries and gut made from colored cloth stitched together onto a T‐shirt to denote the origin and outflow of each peritoneum projection. As the lecturer wears the life‐size model, the students can appreciate the 3D organization of the peritoneal cavity on a living body. In addition, the T‐shirt model can be used in parallel with dissection to ensure a strong reinforcement of the spatial understanding of the peritoneal cavity. Anat Sci Educ. © 2012 American Association of Anatomists.