粘性土起动流速影响因素试验研究

由于粘性土颗粒间粘结力的作用,使得其具有较强的抗冲性和较高的起动流速,这对河势的演变造成一定的影响。为此,通过粘性土起动试验,分析了淤积固结过程中粘性土的物理参量变化情况,建立了干密度、粘粒含量(粒径)与起动流速之间的关系。结果表明,粘性土的粘聚力随含水率的增大而减小,相同含水率条件下,粘粒含量越高粘聚力越大;起动流速随干密度、粘粒含量的增大而增大,粘性土起动流速受中值粒径的影响,实质上与粘粒含量对起动流速的作用相同。在此基础上分析了粘性土起动流速影响因素,提出了起动流速经验公式。研究结果为进一步分析粘性土层对河势演变的影响奠定了基础。

大学生自杀意念状况与负性生活事件的关系:心理资本的中介作用

目的:探讨济南市某师范院校大学生的自杀意念状况与所经历负性生活事件、个体心理资本的关系。方法:采用青少年生活事件量表、积极心理资本问卷和自杀意念量表对济南市某师范院校499名在校大学生进行问卷调查。结果:大学生自杀意念检出率为8.02%,不存在性别差异。大学生的负性生活事件得分与自杀意念总分呈显著正相关(r=0.32,P<0.01),心理资本水平与自杀意念呈显著负相关(r=-0.60,P<0.01)。Bootstrap方法分析显示心理资本在负性生活事件与自杀意念之间的中介效应占总效应的33.33%。结论:该师范院校学生自杀意念较高,其自杀意念与所经历负性生活事件、个体心理资本高度相关,心理资本在负性生活事件和自杀意念间起部分中介作用。

HORIZONTAL 2-D BASIC EQUATIONS AND SIMULATION OF INTERCHANGE BETWEEN SUSPENDED SEDIMENT AND BED MATERIALS IN ALLUVIAL RIVER

A set of new 2-D equations of interchange between suspended sediment and bed materials was serived by theoretical deduction based on the systematic summarization and assessment the previous studies of simulating the interchange between suspended sediment and bed materials in the Lower Yellow River. This model was used to simulate the erosion and deposition processes caused by the interchange between suspended sediment and bed materials in a sketch channel. The results show that these equations are well consistent with the laws of interchange between suspended sediment and bed materials. Furthermore, compared with previous models, it has important practical value not only because of strong theoretical foundation, but also for smaller amount of calculating work and convenient application in practice.