热压法制备PVA/短切上段稻草复合材料研究

基于农作物秸秆的复合材料有利于减轻资源短缺与环境污染等问题.采用热压方法制备了PVA(聚乙烯醇)/短切上段稻草复合材料,研究了PVA用量、热压温度、热压时间对复合材料拉伸性能及硬度的影响.结果表明,在选定的条件范围内,随着PVA用量增加,材料拉伸强度增加,随着热压温度和热压时间增加,材料拉伸强度降低;材料硬度受加工条件影响较小.     

堆载作用对邻近CFG桩复合地基影响的数值模拟研究

通过有限元分析软件ANSYS11.0,对邻近地面堆载作用下已承载CFG桩复合地基的力学性状进行了分析,对已承载CFG桩复合地基中桩体在不同的地面堆载荷载、堆载作用位置、承台受荷状态以及土体压缩模量等工况中的性状进行了研究,进而分析得出堆载的作用位置、大小以及复合地基所在场地范围内土体压缩模量是几个比较重要的影响因素,对临近堆载的CFG桩复合地基的力学性状影响较大。     

水利水电工程施工地质中编录测绘成图方法综述

地质编录与测绘是重要水利水电工程施工地质工作的一项主要内容,一般地质编录测绘需要完成工程地质图图幅.文中以岩质水平建基面为例,介绍了工程地质平面图图幅的编录测绘成图方法和利用不同方法测绘的各类初始数据进行矢量化计算机成图的方法.     

稀土复合固体超强酸SO_4~(2-)/TiO_2/Ce~(4+)催化合成乙酸环己酯及动力学研究

研究了以稀土复合固体超强酸SO42-/TiO2/Ce4+为催化剂合成乙酸环己酯的反应,在反应温度分别为100℃、110℃、120℃下,测出酯化反应的动力学参数,建立了动力学方程,并与无催化剂作用下合成乙酸环己酯反应的活化能及动力学方程进行了比较.实验结果表明,该催化酯化反应的优化合成条件是:乙酸用量为0.262 1mol时,醇酸摩尔比为1.5:1,催化剂用量为1.0g,带水剂环己烷的加入量为12mL.稀土复合固体超强酸SO42-/TiO2/Ce4+可使反应的活化能明显降低,是合成乙酸环己酯的有效催化剂.     

一类广义集值拟向量变分不等式解的存在性

研究了Banach空间中一类G-可导映射的广义拟向量变分不等式问题,运用KKM定理证明这类问题解的存在性,并在适当的条件下证明了此类问题与Konnov I V和Yao J C等人提出的广义向量变分不等式问题是等价的。     

一类集值映射的周期点集

设（x,d）是紧致度量空间,f：X→X是连续映射,k（X）为X的所有非空紧致子集赋予由d诱导的Hausdorff度量而得到的空间,由,诱导的集值映射f^-：k（X）→K（X）定义为f^-（A）={f（a）：a∈A）,主要考虑（X,f）的周期点集与（k（X）,f^-）的周期点集之间的关系,得到了如下重要结果：证明了若P（f^-）是闭集,则P（f）是闭集,并举例证明了它的逆命题不一定成立;证明了P（f^-）：r（X）能蕴含p（f）：X,并给出了一个反例说明了p（f）=X不一定蕴合P（f^-）=r（X）;证明了在X为有限集时p（f^-）：X能蕴含P（f^-）k（X）。     

UMLS语义网络在社会化标注系统中的应用研究

[目的/意义] 研究统一医学语言系统中语义网络与社会化标注系统结合的深层次应用。[方法/过程] 总结UMLS语义网络的现有应用,分析UMLS语义类型与FrameNet语义类型的特征,构建适合本研究的语义类型,并通过实例梳理社会化标注系统与本体映射的思路。[结果/结论] 提出将所构建的语义类型作为标签归类的分类器以及作为分众分类系统与框架网络本体映射的桥梁。突破传统的基于统计的标签归类方法可为本体与分众分类系统的映射提供新的视角。     

The differential effects of prior knowledge on learning: A study of two consecutive courses in earth sciences

We studied the occurrence and nature of learningin a university first year Introduction toGeomorphology course, and its relations with priorknowledge taught in a prerequisite course, and withthe prior knowledge in the to be learned subjects. Tendimensions of knowledge were tapped before and afterthe course by conventional and cognitive structuremeasures that were derived by the concept mappingmethodology. The fine-grain analysis of learningoutcomes yielded the following results: (a) studentsacquired only a small portion of the content in thecourse Introduction to Geomorphology, (b) the priorgeological and geomorphological knowledge did notaffect the learning of the new geomorphologicalcontents, (c) the minor effects appeared within ratherthan across knowledge dimensions, and they affectedmainly the learning of smaller knowledge units, and(d) concept definition cannot be considereda valid probe of knowledge. The differential effects of prior knowledge question thecentral, global and undifferentiated role that schematheories ascribe to prior knowledge in futurelearning. They call for greater reference to theexposed dimensions of knowledge by suggestingadditional factors to be considered in the sequencingof courses, as well as to the acquisition of complexknowledge with partial meaning of the basic knowledgeunits, and the use of new cognitive structure probesof knowledge.     

Procedures for Evaluating the Impact of Complex Educational Interventions

The application of information and computer technology (ICT) to education, particularly when ICT is a component of a major school reform, raises difficult issues for program evaluation. In many cases even defining the program goal is difficult because so many different changes are often instituted at the same time: installation of a local area network, development of technical support, staff development for integrating ICT into the curriculum and for new teaching methods, and so on. To assist program developers and evaluators in gaining control of such complex interventions in education, two basic procedures are described: the history of the future and program logic mapping. The former is a goals and methods clarification scheme, built around a press release that describes at the projected end of the project what was achieved and how. The latter procedure draws on the goals defined in the history of the future, along with the project strategy, to make explicit all of the major links between project inputs and project outputs. This map then serves as a guide for planning an evaluation that would verify causal linkages as well as outcomes. For each type of node in such a diagram, appropriate evaluation techniques are defined.     

国际科学课程教学方法研究的新世纪图景

科学课程对于学生理解科学的本质、提高公民科学素养具有重要作用。选取Web of Science数据库2000-2016年4127篇有关科学课程教学方法的论文,运用文献计量学和科学知识图谱的方法,对国际科学课程教学法的研究现状进行统计与可视化分析。研究表明,新世纪以来,科学课程教学方法研究的热点主要围绕概念教学,研究前沿主要围绕科学论证、有意义评价以及学生合作。美国在科学课程研究方面具有绝对的强势地位,而中国尚未形成足够的国际学术影响力。