固体超强酸SO_4~(2-)/TiO_2-Fe_2O_3催化合成丁酸丁酯的试验研究

利用正交试验找到用SO42-/TiO2-Fe2O3固体超强酸催化合成丁酸丁酯的最佳反应条件。即反应时间4.0h,催化剂用量为酸质量的1.4%,酸醇比1.2:1,验证实验产率为97.6%。且该实验反应时间相对短,无腐蚀无污染,催化剂可回收可重复使用。     

Method of effective evaluation for examination of chloride ion in concrete

INTRODUCTION For some unknown reasons, perhaps caused bysalt, chlorine ions usually exist in reinforced concreteconsisting of cement, water, aggregate and additionalmaterials, and steel bars. In the presence of water, thechlorine ion reacts with iron existing in concrete andsteel bars to form Fe(OH)2 and FeCl2. The chemicalreactions seriously corrodes the surface of steel barsand damage the concrete, causing gradual decrease ofthe concrete compression and increase of its porosity,…     

高职院校学生信息素质教育的实践与思考

信息收集和处理能力是高职院学生应具备的基本能力之一，本文提出应在课程教学中恰当地运用现代教育技术，强化学生的实践练习，改革考核方式，引导学生注意其它信息的查找，在后续课程中深化训练，以培养学生的信息收集和处理能力。     

英语应用能力考试与高职英语教学改革

英语应用能力考试是衡量高职院校英语教学水平的重要尺度,本文就如何进一步深化英语教学改革、提高英语教学水平、提升英语应用能力考试成绩进行了讨论并提出了相应对策。     

固体超强酸SO4^2-／TiO2-Fe2O3催化合成丁酸丁酯的试验研究

利用正交试验找到用SO4^2-／TiO2-Fe2O3固体超强酸催化合成丁酸丁酯的最佳应条件。即反应时间4．0h，催化剂用量为酸质量的1．4％，酸醇比1．2：1，验证实验产率为97．6％。且该实验反应时间相对短，无腐蚀无污染，催化剂可回收可重复使用。     

美国大学入学考试SAT深度剖析

SAT是美国历史上使用最为广泛、研究最为深入的大学入学考试,至今已有80年的历史。SAT分为推理考试(SAT Reasoning Test)和学科考试(SAT Subject Tests)两类,一般人们常说的SAT指的是SAT推理考试。SAT考试全美统一,SAT推理考试每年举行7次。SAT不是智力测验,也不是学业测验,但近年来,SAT试题的设计与学生们在高中课堂里学习的内容越来越密切地相关起来。     

质的研究效度问题——“我如何判断我的判断是有效的？”

研究者需要判断自己的表述是否再现了研究过程中所有部分、方面、层次和环节之间的协调性、一致性和契合性。研究效度的检验包括诠释学的理解和解释循环、研究参与者检验、同伴检验等。研究者是有限的人。意识到这一点就是意识到我们在判断标准和效度方面是有限的，关键在于审慎思考和真诚的理解与沟通。     

Using crowdsourcing for TREC relevance assessment

Crowdsourcing has recently gained a lot of attention as a tool for conducting different kinds of relevance evaluations. At a very high level, crowdsourcing describes outsourcing of tasks to a large group of people instead of assigning such tasks to an in-house employee. This crowdsourcing approach makes possible to conduct information retrieval experiments extremely fast, with good results at a low cost.     

提高自学考试答题卡识别准确率的探讨及实践

自学考试的客观题机器阅卷因容易受到内外各方面因素的影响而会产生一定概率的误判。为了更好地维护自学考试作为国家考试的公平和公正性,需要分析可能存在的误判原因。本文描述了如何使用数字图像识别技术来提高答题卡的识别准确率,最大程度地降低识别误判率,以提高客观题的阅卷质量。     

Usefulness of dual-language science test for bilingual learners

This study examines the usefulness of the science test presented in a dual-language format in two separate science test booklets, one comprising English-only test items and the other, dual-language test items. The participants were 1720 eight-grade students from 26 secondary schools. Most of the students viewed the dual-language test positively as they felt it enhanced their understanding of the test items. However, only two items were found to function significantly different in the dual-language format. Students’ performance for the two versions of the test was comparable. The results showed that the extra language version did not provide greater accessibility and comprehensibility of the test to the students. The findings may prove valuable to decision-making regarding language accommodation policies for testing in content areas.