高寒地区高速公路中央分隔带节地型钢护栏

为适应高寒地区地形、地物对高速公路中间带安全防护的特殊要求,提出中间带节地型梁柱式钢护栏结构,以满足结构通透易除雪、占地空间小的目的。并根据不同路段的防护需求,开发了一种形式两种等级(Am级、SBm级)的护栏结构。采用计算机仿真与实车足尺碰撞试验相结合的手段对护栏进行安全性评价,结果表明:护栏阻挡功能、缓冲功能、导向功能各项指标均满足规范要求,护栏最大横向动态变形值小于500mm,车辆碰撞后护栏不侵入对向车道。同时也表明计算机仿真技术应用于护栏开发及安全性评价的可行性。     

基于多因素神经网络模型的柴油机NO_x排放预测及试验研究

以发动机转速、进气量、循环油量、发动机出水温度、中冷后进气温度、进气湿度、排气背压、柴油温度作为输入,NO_x排放质量流量为输出,优化隐层节点和迭代次数,并经过样本训练,构建了NO_x排放预测模型。结合台架试验数据,验证了模型的泛化能力,其预测值与试验值间误差小于1.5%。在此基础上,利用模型进一步分析了试验因素的重要度和试验控制性。结果表明:发动机转速、循环油耗、中冷后进气温度、排气背压对柴油机NO_x排放的影响相对较高;进气湿度控制范围过宽,对NO_x排放测试结果影响高于其他因素。     

弹性圆柱壳结构的有源结构声辐射控制研究

A numerical and experimental study was presented on active control of structurally radiated sound from an elastic cylindrical shell.An analytical model was developed for the active structural acoustic control (ASAC) of the cylindrical shell.Both global and local control strategies were considered.The optimal control forces corresponding to each control strategy were obtained by using the linear quadratic optimal control theory.Numerical simulations were performed to examine and analyze the control performance under different control strategies.The results show that global sound attenuation of the cylindrical shell at resonance frequencies can be achieved by using point force as the control input of the ASAC system.Better control performance can be obtained under the control strategy of minimization of the radiated sound power.However,control spillover may occur at off-resonance frequencies with the control strategy of structural kinetic energy minimization in terms of the radiated sound power.Considerable levels of global sound attenuation can also be achieved in the on-resonance cases with the local control strategy,i.e.,minimization of the mean-square velocity of finite discrete locations.An ASAC experiment using an FXLMS algorithm was implemented,agreement was observed between the numerical and experimental results,and successful attenuation of structural vibration and radiated sound was achieved.     

沧州海事 助力黄骅港腾飞

2011年,河北黄骅港仅煤炭输出就达9615万吨,杂货吞吐310万吨;综合港区起步工程胜利完工,5万吨级双向航道开通在即,8个十万吨级码头如期建成,一条46公里长的新航道通向深海。通航后第一年完成吞吐量突破1000万吨;河口港区建设和营运都实现新的突破。黄骅港2011年吞吐量达到1.13亿吨,胜利跨进全国亿吨大     

轻轨列车电力牵引系统安全性预测与控制

到2012年底，中国城市轨道线路数量将超过55条、里程1500公里；未来20年，我国城市轨道交通将处于迅速发展的阶段，列车作为城市轨道交通的主要载体，它的安全可靠运行直接影响城市轨道交通运输系统的可靠性、安全性和运营效率，列车动力系统的可靠性则关乎乘客生命安全。     

400 km/h高速铁路接触网系统研究展望

目前我国已形成了350 km/h高速铁路的成套技术体系,但该技术体系对400 km/h高速铁路的适用性需要重新评估.在高速铁路中,受电弓-接触网系统是列车的唯一供能系统,也是决定高速铁路列车运行速度的关键因素.目前,国内外尚无400 km/h线路开通运行,其理论研究需在充分总结350 km/h研究成果的基础上开展.本文...     

血清G-CSF检测在小儿发热性疾病诊断中的意义

目的　探讨血清粒细胞集落刺激因子 (G CSF)活性在小儿发热性疾病中的诊断价值。方法　采用酶联免疫方法检测了 63例发热性疾病 (急性白血病 1 4例 ,呼吸道感染病 49例 )血清G CSF活性 ,同时采用F 82 0血球计数仪检测外周血中性粒细胞 (ANC)绝对值。结果　非细菌感染性病例血清G CSF呈阴性反应 ,外周血ANC正常或低于正常 ;细菌感染性病例血清G CSF阳性 ,其活性与外周血ANC计数呈正相关 ,而部分急性白血病患儿二者呈负相关。结论　检测血清G CSF活性有助于小儿发热性疾病的诊断、鉴别诊断及指导临床抗生素的合理应     

多弹性支撑设备的同步定相振动控制研究（英文）

This paper describes an analytical investigation into synchrophasing, a vibration control strategy on a machinery installation in which two rotational machines are attached to a beam-like raft by discrete resilient isolators. Forces and moments introduced by sources are considered, which effectively represent a practical engineering system. Adjusting the relative phase angle between the machines has been theoretically demonstrated to greatly reduce the cost function, which is defined as the sum of velocity squares of attaching points on the raft at each frequency of interest. The effect of the position of the machine is also investigated. Results show that altering the position of the secondary source may cause a slight change to the mode shape of the composite system and therefore change the optimum phase between the two machines. Although the analysis is based on a one-dimensional Euler–Bernoulli beam and each machine is considered as a rigid-body, a key principle can be derived from the results. However, the factors that can influence the synchrophasing control performance would become coupled and highly complicated. This condition has to be considered in practice.     

红外探水在厦门海底隧道中的应用

在厦门海底隧道施工中采用红外探测仪进行探水短期预报。介绍了红外探水技术的基本原理和布点方法,通过实例分析了分部红外探测得到的红外辐射场强值和绘出的红外探测曲线,得出探测结论,并和实际情况进行验证,说明探水效果良好,为隧道顺利施工提供科学依据。结合应用情况,提出了当前红外探水技术发展中亟待解决的问题。     

电力机车异步牵引电机矢量控制方法研究

酝酿间接矢量控制为基本方法，对有用先进的信号处理器为计算、控制中心的方案进行了研究。着重针对影响异步牵引电机高效率，高性能运行的转子时间常数随时间变化的问题，提出了一种新的线自适应辨识方法，并所述系统进行了实验室的小功率拖动实验，达到了预期的效果。