连续刚构桥0号块水化热温度场分析

以水口大桥为例,根据实测外界环境温度、浇筑初始温度等条件,按照瞬态热传导方程,运用有限元分析软件ANSYS对该桥0号块水化热温度场进行分析,并将仿真结果与实测数据比较,两者吻合较好。结果表明:混凝土浇筑时的初始温度与瞬态温度场呈线性关系,水化热系数同时影响温度峰值及其出现时间,外界大气温度对后期温度场影响较大。     

四室井筒式地下连续墙水平承载试验研究(英文)

井筒式地下连续墙基础因为存在土芯、墙体和外部土体的相互作用,其水平承载机理复杂。进行了3组不同尺寸的四室模型墙试验。基于模型墙内力和位移测试结果,研究了其水平承载特性。结果表明:不同截面尺寸和埋深的井筒式墙基础在不同水平荷载下的弯矩、剪力、转角、土抗力以及摩阻力分布形状相似;随着墙体截面尺寸和深度的增加,弯矩增大,墙体呈现刚体破坏特征;前墙外侧土抗力随荷载线性增加,成为土抗力的主要贡献部分。     

海船轴频电场建模方法研究

轴频电场是由于螺旋桨转动时因主轴和轴承之间的接触阻抗不恒定而导致流经主轴的腐蚀或防腐电流受到周期性调制而产生,是海船的一个重要目标特征信号.文中利用时谐电流元,从理论上推导了海船轴频电场的数学建模方法,采用该方法只需有限的测量数据即可建立海船轴频电场的数学模型,拟合海船产生的轴频电场分布.     

CO2 emissions from typical cement plants in China

The objective is to know how the CO₂ emits and how much the CO₂ emits due to the cement manufacture in both direct and indirect ways with the increasing concerns about the global warming and the cement plants emitting huge CO₂. A precise method to calculate CO₂ emissions including three processes was established in this paper and a case study was provided. From the case of 23 typical plants in China, we can see the amount of CO₂ emissions at the right level. The summary of CO₂ emissions consists of emissions from raw materials, fuels and electricity. The average result of the 23 typical plants is 0.74 t CO₂ per ton clinker in this study. Therefore, CO₂ emissions from these typical cement plants were pictured and then measured. The creative point is that an approach provides a basic framework to identify various situations in different cement plants in China and other in the rest of the world. The framework would be useful in quantitatively evaluating CO₂ emissions for government to know precisely CO₂ emissions in the cement plants.     

Self-organizing map based quality assessment for resistance spot welding with featured electrode displacement signals

To classify the quality of the resistance spot welding process, a relationship between the welder electrode displacement curve characteristics and the weld shear force has been explored. Eleven statistical features of the displacement signals are extracted to represent the welding quality. Self-organizing map (SOM) neural networks have been employed to discover their quantitative relationship. In order to identify the influence of various displacement curve features, all of the available combinations have been used as inputs for SOM neural networks. Further we analyze the impact of each feature on the classification results, yielding the best quality-indicative combination of characteristics. There is no determinant relationship between the welding quality and the level of expulsion rate. The quality of welding is most impacted by the maximum electrode displacement, the span of welding process and the centroid of the electrode displacement curve. The experiments show that SOM is feasible to assess the welding quality and can render the visualized intuitive evaluation results.     

基于GIS-T中间件的公路管理多源数据共享平台

目前已经建成的公路管理数据库,要么没有结合GIS技术,要么仅仅针对某一方面的具体应用,很难实现业务系统之间的协同运行与数据交换．文中提出基于GIS-T中间件技术建立公路管理分层、分布式多源数据共享平台,通过中间件接口、XML参数传递与数据共享来实现公路管理中多个业务系统之间的协同处理与空间可视化操作,研究了其中的关键问题并提出了解决办法．     

Fast affine projection algorithm for adaptive noise canceling and its application on the fetal electrocardiogram extraction

Aimed at the problem of adaptive noise canceling (ANC), three implementary algorithms, which are least mean square (LMS) algorithm, recursive least square (RLS) algorithm and fast affine projection (FAP) algorithm, have been researched. The simulations were made for the performance of these algorithms. The extraction of fetal electrocardiogram (FECG) is applied to compare the application effect of the above algorithms. The proposed FAP algorithm has obvious advantages in computational complexity, convergence speed and steadystate error.     

活塞环岸高间隙对发动机冷起动瞬态HC排放影响的试验研究

通过改变活塞环岸高间隙的方法研究了活塞环间隙对发动机冷起动HC排放的影响.试验结果表明,在冷起动首循环情况下混合气浓度处于稀燃区时,增加50%的活塞环岸高间隙,HC排放平均升高了25%;当混合气浓度处于稳定燃烧区域时,增加50%的活塞环岸高间隙,HC排放平均降低了32%;当冷起动首循环混合气浓度处于浓燃区时,活塞环岸高间隙增加50%,HC排放平均提高了18%.     

基于MSP430单片机的多路信号采集系统

根据微弱模拟信号的检测需要,利用AD7706具有低功耗、高精度A/D转换的特点,以MSP430F149为控制器,设计了一种多路信号采集系统,编制了A/D转换以及MSP430F149与PC机之间的串行通信软件,实现了采集到的数据能在PC机上显示、存储、绘制曲线,同时PC机能给单片机发送控制命令等功能.实践表明该系统能可靠运行.     

CFA6470HEV发动机燃油经济性的BP神经网络建模及优化

对MATLAB软件中的BP神经网络及数值分析方法进行了研究,并将其应用于CFA6470HEV发动机特性的建模,在对模型的结构参数优化的基础上,获得了合适的发动机特性模型.应用数值分析方法确定了发动机的最优经济性运行区间以及与之对应的发动机节气门开启角与转矩和转速之间的关系,利用此关系,可通过对发动机节气门的调节实现对发动机最佳燃油经济性的控制.