等离子体平面反射电磁波的模拟仿真

考虑热运动、电子复合、碰撞等效应,建立电磁波与平面等离子体相互作用模型,计算了电磁波入射不同等离子密度的平面等离子体时,对等离子体密度的影响,并对入射与反射电磁波幅频特性进行了比较。同时分析了碰撞频率、复合系数变化对反射波的影响。这对等离子体平面天线的设计较有价值,而且为下一步的实验提供了参考依据。     

膨胀岩土地层盾构隧道结构力学行为研究

文章在提出膨胀接触压力概念的基础上,采用接触单元对膨胀接触压力和膨胀力的关系进行了研究,得出了膨胀接触压力与膨胀岩土分布、厚度、结构及地层刚度等的关系;同时对膨胀岩土地层中盾构隧道"荷载-结构"模式外荷载及"梁-弹簧"模型的特点进行了分析;并将其分析结果直接应用到成都地铁2号线膨胀岩土地层盾构隧道的结构分析中,得出了盾构隧道在不同膨胀岩土层、膨胀力、埋深和拼装方式条件下的结构内力值,对隧道结构设计起到了指导作用。     

Comparison of osteogenesis between two kinds of stem cells from goat combined calcium phosphate cement in tissue engineering

To explore the possible mechanism of osteogenesis for deciduous teeth stem cells (DTSCs) in vivo/ vitro, stem cells from goat deciduous teeth (SGDs) were firstly isolated, induced and transplanted into immunocompromised mice. The SGDs’s mineralization pattern and osteogenesis were compared with bone marrow messenchymal stem cells (BMMSCs) from goats. SGDs have similar osteogenic differentiation pattern in vitro and bone-like tissue formation mechanism in vivo to BMMSCs; moreover SGDs have stronger alkaline phosphatase (ALP) gene expression and osteopontin (OPN) gene expression levels than BMMSCs; also SGDs can form more bone-like tissues than BMMSCs when cell-scaffold compounds are transplanted into immunocompromised mice. This pre-clinical study in a large-animal model confirms that DTSCs may be an appropriate source of stem cells in repairing bone defects with tissue engineering.     

农村公路网等级结构灰色多目标优化模型研究

通过分析当前农村公路网等级结构确定方法,指出路网等级结构确定方法中优化目标的优先顺序以及在约束条件下的技术系数和资源约束都存在灰度的问题.运用灰色系统理论原理,构建了农村公路网等级结构灰色多目标优化模型.该模型使公路网规划者在农村公路网等级结构确定存在灰度的情况下,得到满意可行的结论.     

港口机械负荷敏感液压系统的节能特性研究

基于负荷敏感液压系统的工作原理,建立其Amesim模型,仿真分析3种工作状态下的液压系统特性.结果显示,负荷敏感液压系统能够自我调节泵流量和工作压力以适应执行机构的要求,减少系统中的溢流损失,实现液压系统的节能.     

Long-term tracking based on spatio-temporal context

Aiming at the problem that the fast tracking algorithm using spatio-temporal context (STC) will inevitably lead to drift and even lose the target in long-term tracking, a new algorithm based on spatio-temporal context that integrates long-term tracking with detecting is proposed in this paper. We track the target by the fast tracking algorithm, and the cascaded search strategy is introduced to the detecting part to relocate the target if the fast tracking fails. To a large extent, the proposed algorithm effectively improves the accuracy and stability of long-term tracking. Extensive experimental results on benchmark datasets show that the proposed algorithm can accurately track and relocate the target though the target is partially or completely occluded or reappears after being out of the scene.     

阿布森回收SBS改性沥青的试验研究

客观、准确地评价旧沥青的老化程度是沥青路面再生技术的基础,而正确回收旧沥青是基础中的基础,影响到再生技术方案的决策、新材料的选择、再生混合料设计等。现行阿布森法回收沥青的试验规程(T0726-2011)是根据普通沥青而制定的,并不适用于SBS改性沥青。该文以阿布森回收方法为试验基础,通过分子扩散理论与表面张力机理分析,确定试验控制的关键参数。通过空白改性沥青标定试验对关键控制参数进行优化与验证。结果表明:SBS改性沥青可以采用阿布森法回收,回收的SBS改性沥青的三大指标、黏度、弹性恢复与空白沥青基本一致。提出了改性沥青回收的关键步骤,规范了改性沥青回收的溶液浓度、蒸馏温度、CO2通气量以及延迟加热时间等关键控制参数。     

填方土体湿化变形数值模拟

介绍了湿化变形计算模式,将无拉应力模型应用到湿化变形计算.应用该模型,利用有限元对算例进行了不同湿化参数下湿化引起的位移计算,并对结果进行了分析,提出了一些建议,为工程设计提供参考.     

Flexible feeder transit route design to enhance service accessibility in urban area

To improve the accessibility of transit system in urban areas, this paper presents a flexible feeder transit routing model that can serve irregular‐shaped networks. By integrating the cost efficiency of fixed‐route transit system and the flexibility of demand responsive transit system, the proposed model is capable of letting operating feeder busses temporarily deviate from their current route so as to serve the reported demand locations. With an objective of minimizing total bus travel time, a new operational mode is then proposed to allow busses to serve passengers on both street sides. In addition, when multiple feeder busses are operating in the target service area, the proposed model can provide an optimal plan to locate the nearest one to response to the demands. A three‐stage solution algorithm is also developed to yield meta‐optimal solutions to the problem in a reasonable amount of time by transforming the problem into a traveling salesman problem. Numerical studies have demonstrated the effectiveness of the proposed model as well as the heuristic solution approach. Copyright © 2015 John Wiley & Sons, Ltd.     

风行MPV车车内噪声分析与控制

阐述东风风行MPV车室内噪声的主要来源,介绍整车隔音降噪工程在东风风行MPV车上的具体运用,通过隔音材料的比较,提出了相应的控制措施,并结合成本控制因素,对降噪过程进行优化。