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91.
偏心螺旋传动试验台是一种新型的螺旋传动试验台,有其独特的传动原理、结构、试验方法及其应用。  相似文献   
92.
Based on the Job Demands-resources (RD-R) model, the aim of the current study was to examine how pressure arising from imposed curriculum changes and teacher self-efficacy relate to perceived stress in teachers. Participants (839 teachers working in English schools) completed an online survey that contained questions about demographics, self-reported pressure from imposed curriculum changes, teacher self-efficacy, and perceived stress. Pressure from imposed curriculum changes was positively, and teacher self-efficacy negatively, related to perceived stress. Teacher-self efficacy moderated relations between pressure from imposed curriculum changes and perceived stress. High teacher self-efficacy was associated with lower perceived stress, relative to low teacher self-efficacy, when pressure from imposed curriculum changes was low. The differential advantage offered by high self-efficacy declined as pressure from imposed curriculum changes increased.  相似文献   
93.
有机化学实验考核方法的改革和探索   总被引:2,自引:0,他引:2  
通过对传统有机化学实验考核方法弊端的分析,阐述了改革传统考核方法的必要性,建立了新的考核方法,设计了有机化学实验考核评估指标体系,并将评估指标转化为可操作的教学行为,促进了教与学,做到了全方位、客观地评价学生的实验课成绩。  相似文献   
94.
Franz Riffert 《Interchange》2005,36(1-2):231-252
First an overview is given about the actual national and international situation concerning standardized testing. Then two major reasons are presented why accountability systems based on standardized testing have become so widespread: (a) the missing validity and reliability of teachers’ assessment of students’ achievement, and (b) the important role standardized testing plays for out-put management in educational systems.On the basis of these considerations Alfred North Whitehead’s critical remarks on external standardized testing are presented. Whitehead’s main point is that external standardized testing limits the freedom of teachers to adapt to the complex, situation specific circumstances in order to obtain a maximum of the creative learning process for students who are conceived as specialists. Instead external testings lead to “teaching to the test.” As a consequence, the attitude of creative, adventurous exploration is undermined and substituted by simple pattern recognition, narrow visions, and even boredom. Finally, the question is raised whether there is any possibility of developing a measurement tool which on the one side meets scientific test criteria, and on the other side is still flexible enough to do justice to needs of individual schools – which according to Whitehead are the essential educational unit – and not vice versa, as it is the case at present with external standardized testing. That such a flexible approach to evaluation is possible is demonstrated by the presentation of the basic ideas of the MSS (Module Approach to Self-Evaluation of School Development Projects) which has been developed and examined in ten schools by the author and his collaborators.  相似文献   
95.
论英语节奏     
阐述了英语节奏的特点,论述了英语节奏与词重音、句重音、重音规整性,音长、元音的音质、语调和语言的可理解性三者之间的相互关系和影响。提出了掌握英语节奏的正确方法。  相似文献   
96.
不同品种黄瓜幼苗光合机构对盐胁迫的响应   总被引:26,自引:0,他引:26  
研究了盐胁迫(0、25、50mmol/L)对不同品种黄瓜幼苗生长、光合作用和叶绿素荧光的影响.结果表明,盐胁迫,尤其是高浓度NaCl(50mmol/L)的胁迫,显著降低黄瓜幼苗生长量、叶绿素含量、光系统Ⅱ光合电子传递量子效率(φPSⅡ)、净光合速率(Pn)、气孔导度(Gs)以及气孔限制值(Ls),同时显著提高叶片相对电导率、丙二醛、脯氨酸含量和细胞间CO2浓度(Ci),光系统Ⅱ的光化学效率(Fv/Fm)变化不大.盐胁迫对耐盐黄瓜‘津研4号’幼苗生长的影响小于盐敏感黄瓜‘津绿4号’,这可能与耐盐黄瓜在盐胁迫下较高的净光合速率、光系统Ⅱ光合电子传递量子效率和较低的丙二醛(MDA)含量、相对电导率有关。  相似文献   
97.
为了探索元极学在实际中的应用,采用智力测验方法,对学习元极学的深浅程度不同者进行了测试和研究,结果表明,学习元极学对开发智力的某些方面如记忆、动作协调、注意分配等有一定作用,学习的程度越深,对智力的开发越大。  相似文献   
98.
为了保障机载无线电设备的正常工作,完成对机载无线电设备进行定期检测和维修,我们提出了机载无线电设备测试系统的一种优化设计,配合软件系统以后,使大部分信号分析比较,以及对输入信号,电源控制等方面充分实现智能化,本文主要介绍了用Protel99来实现此机载无线电设备综合检测系统的硬件设计方案以及基本设计框图。  相似文献   
99.
给出新型三类用理性杂交模式、根据一种修正的Hellinger-Reissner原理、建立高精度非协调轴对称实体旋转有限元时,其单元刚度矩阵的准确计算式。  相似文献   
100.
Leaf senescence is often caused by water deficit and the chimeric gene PSA612-1PT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance (TBARS) and antioxidant enzymes activities were investigated during leaf senescence of PSA612-1PT modified gerbera induced by osmotic stress compared with the control plant (wild type). Leaf discs were incubated in 20%, 40% (w/v) polyethylene glycol (PEG) 6 000 nutrient solution for 20 h under continuous light [ 130 μmol/(m^2·s)]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and dehydroascorbate reductase (DHAR) were stimulated by PEG treatment. However, the increases were higher in PSA612-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation (TBARS content) was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities ofantioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.  相似文献   
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