脱硫石膏的施用量对盐碱地葵花生长的影响

采用拉丁方田间试验设计,测定脱硫石膏在不同施用量条件下对盐碱地的改良效果.结果表明:施用脱硫石膏显著提高了土壤有机质和养分含量,一定程度上降低了土壤碱化度、pH值和全盐含量,提高了葵花出苗率、千粒重和产量.根据脱硫石膏施用量与葵花出苗率、产量的模拟曲线关系,测得利用脱硫石膏改良盐碱化土壤的最佳施用量为28.0 t/hm2左右.     

一个非局部波动方程组解的爆破增长率的估计

本文考虑如下非局部波动方程组的初值问题:这里0相似文献   

Predicting higher education outcomes and implications for a postsecondary institution ratings system

The accountability of colleges and universities is a high priority for those making policy decisions. The purpose of this study was to determine institutional characteristics predicting retention rates, graduation rates and transfer-out rates using publicly available data from the US Department of Education. Using regression analysis, it was determined there are 14 predictors of the full-time retention rate, 7 predictors of the part-time retention rate, 15 predictors of the graduation rate and 12 predictors of transfer-out rates. Institutions and policymakers could use the results of this analysis to determine the policies that would be beneficial to improving the analysed outcomes. All four analyses indicate good fit with R² ranging from .273 to .828. Some possible policy implications include addressing selectivity if institutions want to improve retention rates and addressing affordability to improve retention and graduation rates.     

Simple shear endochronic eqiations for finite plastic deformation

The endochronic equations proposed by Valanis (1980) were extended to a finite deformation range. Jaumann's rate,Fu's rate and Wu's rate were incorporated into the endochronic equations to analyze simple shear finite deformation. Incremental equations and numerical solutions are deduced for three endochronic objective models. The results show that an oscillatory shear stress response to a monotonically increasing shear strain occurs when the Jaumann's rate objective model is employed for endochronic materials. The oscillatory response is dependent on the adopted objective rate. Compared with the Jaumann's rate, the Fu's rate and the Wu's rate satisfy the restrictions to elastic-plastic constitutive relations and are in agreement with the experimental results.     

百农AK58小麦光合特性的研究

在大田条件下,研究了百农AK58及温麦6号、新麦18号、周麦18号 4个小麦品种旗叶的光合作用特性.研究表明:百农AK58、温麦6号、新麦18号和周麦18号旗叶净光合速率/光合有效辐射的拟合系数分别为:0.91,0.59,0.43,0.79;最大净光合速率分别为:22.8μmol·m2·s-1,20.6μmol·m2·s-1,19.4μmol·m2·s-1,21.5μmol·m2·s-1;光补偿点分别为:75.9μmol/(m2·s),24.2μmol/(m2·s),76.9μmol/(m2·s),115.4μmol/(m2·s);CO2补偿点分别为:75.5 μmol/mol,43.7 μmol/mol,75.6 μmol/mol,81.5 μmol/mol.结果表明:百农AK58小麦品种具有较强的耐高温、强光特性和较好的光合生产潜力.     

关于我国教育发展与收入差异研究

文章运用1978年以来有关统计数据进行实证,发现我国近几十年教育的发展不断扩大了城乡居民收入差异和各地区经济发展的差距。因此建议重视农村和欠发达地区教育发展,鼓励和扶持大学生到农村和欠发达地区创业。     

合理配料,提高水泥熟料质量

水泥的强度低，安定性不合格，主要是配料不当的原因造成的．选择合理的配料三率值是提高水泥质量的关键，合理的配料三率值是利用水泥生产技术，结合本厂原料的具体实际在生产实践中不断摸索出来的。     

改进的FCG软件试验数据处理方法

应用软件FCG(MTS Fatigue Crack Growth TestW are)采用七点递增多项式局部拟合的方法,计算疲劳裂纹扩展速率da/dN,导致计算值分散度很大。经过详细分析,提出采用正交多项式的线性组合作为疲劳裂纹长度a与载荷循环数N之间关系的拟合目标函数,再用直接求导的方法计算da/dN。这样减小了da/dN的分散度,提高了Paris公式参数拟合和门槛值计算的精度。     

Approaches to Study and the Quality of Learning. Some Empirical Evidence from Engineering Education

In the late 1990s failure rates in a first-year introductory calculus course at the Norwegian University of Science and Technology reached peak levels. This paper reports on findings from an action research project that was set up in 2002/2003 to improve the situation. The study confirms that students approach their tasks differently which contributes to qualitatively different learning outcomes. Furthermore, patterns of achievement in mathematics and physics in secondary education keep reoccurring in the calculus course, even though the teaching and learning contexts are different. The paper does not provide any definite answer as to why groups of students get involved in distinctly different learning processes, and it will take further research to decide the nature of commitment to the learning tasks. However, inspired by the notion of ‘practices’ this paper raises a discussion about the role of intentionality in learning processes. When doing mathematics, students are also in a process of being engaged in and developing a practice. It is a major challenge for academic staff to contribute to communities of practice that are conducive to learning.     

试析中国公务员考核制度的激励功能--兼谈考核制度存在的问题与改进对策

分析了公务员考核制度的激励功能以及存在的主要问题,提出了改进我国公务员考核制度的对策和建议。