飞机用铝合金-CFRP搭接结构的电偶腐蚀预测研究

目的通过有限元仿真,预测飞机复合材料-铝合金搭接试件可能产生的腐蚀部位和腐蚀深度。方法采用动电位极化的方法,测得温度为40℃的5%NaCl溶液中铝合金和复合材料两种材料的极化曲线。以极化曲线及其拟合的电化学动力学参数作为边界条件,建立电偶腐蚀仿真模型。通过模型计算,分别得到两种材料的腐蚀预测结果,将其结果与实验室腐蚀试验结果进行对比。结果电偶试件模型预测得到的电偶电位值与实验测量得到的电偶电位值对比误差为4.2%。搭接试件的腐蚀部位为偶接处3 mm内,其腐蚀分布与搭接件电偶腐蚀模型预测的电位分布规律基本一致,腐蚀深度的预测值和腐蚀实验的实测值对比误差为12.5%。结论该研究的仿真预测结果与试验结果在一定程度上具有一致性,证明了仿真模型的正确性。     

移动床生物膜反应器的研究及应用现状

移动床生物膜反应器是一种高效的污水处理系统 ,目前在国内外已有较多应用。本文就其特点及研究应用状况作简要介绍。     

Enhanced experimental flexibility and control in ecotoxicological mesocosm experiments--a new outdoor and indoor pond and stream system

Scope The German Federal Environmental Agency has put into operation a new modular mesocosm system consisting of eight outdoor and eight indoor ponds and streams in order to investigate fate and effects of chemicals and municipal wastewater in aquatic ecosystems. General design and special characteristics are given to demonstrate the wide range of possibilities for experimental research. - General design. Each of the 16 streams with riffle and pool sections can be varied in length up to 106 m. The streams can be run as circular or flow-through systems at a flow velocity of 0.02 to 0.6 m/s. Physico-chemical standard parameters are measured on-line. The 16 ponds, which can be connected to the stream systems, are equipped with drainage and pore water-sampling devices for simulating processes in the littoral zone including influent and effluent ground water flow. Perspectives Since the highly flexible and controllable construction also allows treating a wide range of hydrological and ecological experiments external institutions are invited to submit proposals.     

规划环评和区域开发环评的比较研究

对区域开发环境影响评价与规划环境影响评价进行了比较研究,指出当前区域开发环评中存在的问题,并提出若干建议。     

颤振飞行试验激励技术发展的回顾和展望

首先对颤振发生机理、颤振飞行试验实施过程及颤振激励的重要性进行了简单介绍,然后对颤振激励方法的发展历程进行了回顾,对不同颤振激励技术的特点进行了详细分析,并提出了激励技术的选择原则和方法,得出不同激励方法的最佳适用对象。最后,结合新型飞机技术发展需求,对颤振激励技术的发展趋势进行了展望。不同的颤振激励技术服务、支持了不同型号飞机的飞行试验工作,随着各种超高速、轻型化、智能化飞机的出现,对各种新型颤振激励技术的需求会层出不穷,文中的工作对不同特点试验飞机颤振激励技术的选用给出有益的建议和参考。     

大型运输机水上迫降动力学分析及模型验证

目的 完善大型运输机水上迫降分析方法,提高分析精度。方法 以有限元和SPH方法为基础,开展大型运输机水上迫降动力学仿真。基于冯.卡门经典入水冲击理论,构造大型运输机机身底部吸力模型,提出基于工程修正的水上迫降动响应分析方法,并通过试验验证。结果 通过分析得出,飞机接水后,机头迅速上扬,俯仰角达到峰值后,机头向下运动,俯仰角逐渐减小,分析得到的飞机姿态变化与试验的变化趋势基本一致。结论 水上迫降模型试验表明,分析误差能够满足工程设计要求。     

An observational study of child safety seat use in an international safe community: Tehran,Iran

Objective: Despite strong evidence of the effectiveness of child safety seats in reducing injuries, the use of these devices in some communities is still rare. The purpose of this study was to determine the prevalence of child safety seat use and the factors influencing its use in the safe community of Tehran.

Methods: This roadside observational study was conducted in 2015 and 2,178 personal cars with a child under 12 years aboard were observed on Tehran's streets in regard to use of child safety seats. Other variables such as the gender of the driver, driver's age group, type of street, region of municipality, time of day, and day of the week were also collected.

Results: Prevalence of child safety seat use was 4.3% and was significantly higher among women drivers, on freeways, and in municipal regions 1, 4, and 7.

Conclusions: The prevalence of child safety seat use in Tehran as a most populous member of the international safe community was very low and most children commuted in insecure situations in the vehicle. Therefore, it is proposed that plans should be made to increase the use of child safety seats in international safe communities.     

飞机飞行振动预计技术研究

介绍了飞机飞行振动的主要来源和特征,分析了传统预计方法的不足,针对飞机飞行振动与高度、马赫数和攻角等飞行参数呈非线性关系的特点,提出了基于BP神经网络的飞行振动预计新技术,建立了预计模型,通过8组建模样本训练网络,确定了预计模型中的各个参数值。预计结果和实测飞机飞行振动信号比较分析表明,该方法预计精度高,验证了BP神经网络预计飞机飞行振动的可行性。     

小水电资源区域开发环境影响回顾性评价案例分析——以海南省为例

在小水电资源区域开发规划环境影响报告书编制中应设置小水电资源区域开发环境影响回顾性评价专题,对规划区域小水电资源开发过程产生的环境问题进行调查和回顾性评价,从中发现小水电资源开发存在的环境问题,并提出规避的对策。海南省小水电资源开发规划环境影响报告书小水电资源区域开发环境影响回顾性评价专题案例。通过遥感影像判读及现场调查发现,选址不当、断流、减水、沙化、景观破坏、植被覆盖率降低及外来物种入侵、水土流失、用水矛盾、影响渔业资源等环境问题普遍存在,主要原因是环境行政管理虚位。主要对策有：在小水电资源开发规划及项目可行性研究报告中,应将环境法规符合性及环保投资列为重要内容;实施工程环境监理;加强竣工环保验收;将水电站下泄生态流量等环保措施执行情况的现场检查纳入常态工作范畴。     

军用飞机结构类型聚类分析

选取某型飞机16个典型结构,采用温、湿度测量仪测量其局部温、湿度,测量周期为2个月,分别获得673个有效温、湿度实测数据。根据实测数据,采用模糊聚类算法对飞机结构类型进行归并分析,当模糊矩阵阈值λ=0．7时,飞机结构类型可归并为开式、半开式、封闭式3种典型结构形式。