三阶非线性中立型阻尼泛函微分方程的振动性

研究一类三阶非线性中立型阻尼泛函微分方程,利用广义Riccati变换和积分平均技巧,建立了该类方程的所有解振动或收敛于零的若干新的充分条件,推广和改进最近文献的结果.     

北京高校学生生活垃圾源头分类行为及其影响因素研究

生活垃圾源头分类制度的推广受到了社会的广泛关注。结合计划行为理论及相关文献提出5个研究假设,根据对北京市10所大学500余名在校大学生问卷调查的统计结果,分析了影响高校学生进行生活垃圾源头分类的因素,从政策制定、宣传教育、基础设施建设及创新体制机制等方面提出对策建议。     

热输入对Q460钢焊接接头组织及拉伸变形行为的影响

以Q460钢为对象，研究了埋弧焊热输入对其接头组织及其拉伸变形行为的作用规律与机理.结果表明:接头HAZ宽度随热输入增加而增大，同时FZ柱状晶比例也增加，FZ靠近熔合线的组织明显细化，且FZ的软化得到改善.热输入对接头整体强度无明显影响，而断裂延伸率呈增加趋势.19.0kJ/cm下焊接接头FZ与HAZ界面的变形不协调，导致过早发生断裂.随热输入的增加，FZ组织细化，缓解了FZ与HAZ界面硬度差，提高了接头的塑性变形能力，拉伸断裂位置由FZ转移至BM.     

非经典阻尼隔震结构近似实空间解耦分析

提出了可应用于中低层和多高层隔震结构的近似实空间解耦方法.利用强迫解耦法、Kelly法和近似实空间解耦法对具有非经典阻尼特性的隔震结构进行了对比分析,并将结构位移响应用具有明确物理与工程意义的系列二阶标准振子位移响应与速度响应线性组合来表示.通过理论分析和算例求解可知:近似实空间解耦法具有很强的优越性和很高的计算精度,结构隔震层和顶层的位移响应最大误差仅为0.361%和1.444%,可推广应用于隔震结构的动力响应分析.     

Evolutionary game analysis of low-carbon behavior credit supervision of logistics enterprises

Based on the low-carbon obligation fulfillment of Chinese logistics enterprises, this study constructs a tripartite evolutionary game model to analyze the evolutionary process of the interaction between the local government, logistics enterprises and the public in the process of low-carbon behavior credit supervision. Then using Netlogo software, a parameter simulation experiment is conducted to determine the optimal policy for improving the effect of supervision. The results are as follows: ① The combined influence of the local government and the public can effectively change the strategic choice of enterprises and promote the low-carbon behavior of enterprises. ② In terms of improving the effect of supervision, reducing the cost of government supervision would have a highly significant effect, and reducing the cost of the public would be counterproductive. ③ Increasing the government subsidies to enterprises and the government’s fines to enterprises both have a significant effect, and the effect of improving the former is better. However, increasing the severity of higher-level governments punishing local governments will reduce the stability of the system. ④ Supervision can be more effective by increasing the public’s impact on enterprises’ earnings rather than by increasing government subsidies to the public.     

Microstructure evolution and reaction behavior of Cu–Ni alloy and B_4C powder system

Microstructure evolution and reaction behavior of Cu–Ni alloy and B_4C power system was studied by in-situ and static experimental investigations along with theoretical calculations. The reaction process was as follows. Firstly,B_4C decomposed into B and C atoms, and then B atoms diffused into Cu–Ni matrix, leading to the formation of Ni_2B particles. Subsequently, Ni atoms diffused into B_4C, forming a loose mixture of Ni_2B and amorphous C at the initial powder boundary. Finally, with the completion of reaction, Ni_2B particles at the powder boundary grew into a monolithic block, and then C substance was excluded out and accumulated at the edge of this monolithic Ni_2B block. It is believed that the formation of Ni_2B phase is caused by the most negative change of Gibbs free energy among all the potential reactions between Ni–B and Ni–B_4C systems.     

考虑用户行为和排错延迟的多版本软件可靠性增长模型

软件在测试阶段和使用阶段操作环境的差别导致软件测试可靠性和运行可靠性不完全相同.软件在发布后的使用和维护阶段,软件可靠性的增长不仅体现在软件固有故障的排除,而且用户对软件的熟悉程度也会影响软件的可靠性.本文研究了软件固有故障检测过程、固有故障纠正过程和外在失效过程的特征,建立了考虑用户行为和排错延迟下的多版本软件可靠性增长模型.通过一组来自于开源软件用户缺陷跟踪系统中的真实数据进行数值分析,试验结果表明提出的模型具有较好的效果.     

基于活动的瓶颈模型:公交枢纽晚高峰居民通勤研究

如何快速消除公交枢纽瓶颈的制约,是居民通勤的老大难问题.本文结合瓶颈模型与基于活动的方法来研究公交枢纽晚高峰居民通勤行为,以解决通勤者在其活动和出行之间的时间分配问题.以瓶颈模型为基础,考虑公交内部拥挤,将出行行为与活动相关联.通过引入公交内部拥挤成本,根据不同的效用函数选择出发时间,建立了动态出行均衡模型.并由此得出均衡条件下的相关性质,来解释晚高峰通勤者在瓶颈入口前排队的交通现象.研究发现,与传统瓶颈模型相比,基于活动瓶颈模型乘客动态更加丰富,出发时间选择更为复杂.算例结果表明,通勤者对公交车内部拥挤的敏感度越高,越会尽量地避开高峰出行.为了使净效用更大,通勤者会选择在工作地滞留较长时间,晚高峰时段推迟.     

一类二阶中立型广义Emder-Fowler阻尼方程的振动准则

考虑一类具阻尼项的二阶中立型广义Emder Fowler方程解的振动性, 先借助Riccati变换对非线性项和阻尼项进行处理, 达到线性化的目的, 再利用Philos的积分平均方法, 建立这类方程解的振动准则.     

互联网金融环境下智能投顾对于投资行为的影响

基于国内知名网贷平台的数据，采用固定效应模型和双重差分分析方法，研究了智能投顾的使用对于投资者的投资金额和风险偏好的影响。实证结果表明，智能投顾的使用会减少投资者的单笔投资金额，增加投资者的总投资金额，并使得投资者的风险偏好趋于保守。研究结果丰富了智能投顾和行为金融学的研究内容，加深了智能投顾企业对于投资者行为的理解，使其可以更好地设计和完善相关服务。