结合神经网络和数据融合技术的城市路段速度估计*

大部分基于浮动车GPS数据的速度估计模型仅适用于GPS数据采样时间间隔小、样本量空间分布密集的理想情况,无法准确计算样本量不足情况下的实时速度.根据浮动车GPS数据点在空间上的分布情况,提出组合三种速度估计模型,以最大限度地提高GPS数据利用率;考虑到GPS数据点在时间上分布不均,在GPS数据不足的情况下,结合神经网络预测和数据融合的技术,根据误差方差融合速度估计模型的测量值和神经网络拟合的预测值,以减少实时估计误差.选择广州市东风路作为测试实例,在高峰和平峰两种交通场景下比较了融合值、测量值和预测值的误差,结果表明结合神经网络和数据融合技术的城市路段速度估计精度和稳定性均优于速度估计模型.     

High‐solids mar resistant clearcoats prepared from an isophthalate‐based oligoester and a melamine resin. Study and characterization of mar resistance with scanning probe microscopy method

A new series of high‐solids [low‐VOC (volatile organic compound)content] mar resistant clearcoats (CL‐series) were prepared upon crosslinking of a new‐synthesized hydroxyl‐terminated isophthalate‐based liquid oligoester (L‐311) with an hexakis(methoxymethylol)melamine (HMMM) resin, via an acid‐catalyzed etherification reaction. The chemical, physical, and mechanical properties of the CL‐clearcoats were compared to those of a reference clearcoat (CRO). An attempt was made to investigate the effect that the amounts of catalyst and melamine resin had on the clearcoats' physical, chemical, and mechanical properties, and moreover, to correlate these properties to the films chemical structures. The new‐formulated high‐solids clearcoats (CL‐series) presented enhanced processability and higher NVW values (lower VOC content) than the reference clearcoat CRO, and their properties (pencil hardness, knoop hardness, adhesion, impact resistance, solvent and gasoline resistance, mar resistance, and flexibility) were better or comparable to those of the CRO. More specifically, the mar resistance of the CL‐clearcoats series was investigated by applying both the crockmeter test and a novel method that employed a modified scanning probe microscope. In addition, we identified and characterized the different responses of the CRO and certain CL‐clearcoats to marring stress. The experimental data regarding the mar resistance of the new‐formulated clearcoats fully justified our polymer design strategy, verifying our expectations for the possibility of preparing glossy, high‐solids mar‐resistant clearcoats that could present enhanced processability and solvent resistance, relatively high pencil hardness, and at the same time very good elastic recovery to marring stress. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1317–1333, 2002     

Effects of temperature on local two-phase flow structure in bubbling and turbulent fluidized beds of FCC particles

A novel high temperature optical fiber probe has been developed to study the effects of bed temperature on the local two-phase flow structure in a pilot scale fluidized bed of the FCC particles with bed temperatures ranging from 25°C to 420°C, covering both the bubbling and turbulent fluidization regimes. The results show that fluidization is enhanced and fluctuations of the local two-phase flow structure become more intense with increasing bed temperature. At constant superficial gas velocities, the averaged local particle concentration, the dense phase fraction and particle concentration in the dense phase decrease with increasing bed temperature, whereas both the frequency of the dilute/dense phase cycle and the ratio of the dilute phase duration to the dense phase duration increase. In addition, the effects of temperature on the dilute phase depend on superficial gas velocity. The conventional two-phase models fail to predict these changes of the local flow structure with temperature, which may be explained by the fact that the role of interparticle forces is neglected at different bed temperatures. Indeed, fluidization behaviors of the FCC particles tested increasingly shift from typical Geldart A towards B with increasing temperature due to a decrease of the interparticle attractive forces and a simultaneous increase of interparticle repulsive forces.     

基于RBF神经网络逼近算法的船舶支架减振器挤压测试系统

为了获得船舶支架减振器挤压形变量与环境温度关系,提出基于RBF神经网络逼近算法的船舶支架减振器挤压测试系统。该系统通过光栅位移传感器、温度传感器对位移数据和温度数据的采集,实现了数据存储和显示。并采用RBF神经网络逼近算法减小数据误差。最后通过MATLAB仿真和某舰船支架减振器实际测量,证明了该测试系统具有较高精度和准确性。     

搅拌槽内温度对气含率的影响

Gas holdups in ambient gassed and hot sparged systems with multiple modern impellers and the effect of temperature on gas holdup are reported,The operating temperature has a great impact on gas holdup though the gas dispersion regime in the hot sparged system is similar to the ambient gassed condition,The gas holdup under the elevated temperature and the ambient gassed operation is successfully correlated.With the sarme total gas flow rate and power input,the gas holdup in the hot sparged system(say near the boiling point)is only about half of that in the ambient system ,The results imply that almost all existing hot sparged reactors have been designed on the basis of incorrect estimates of the gas holdup during operation.     

基于次氯酸根离子的新型比率型荧光探针及其应用

以2-苯并噻唑-5-甲基苯酚为原料,合成了一种基于次氯酸根离子的比率型荧光探针ZN1,并对其进行了次氯酸根离子的检测性能测试。结果表明:该探针可以快速灵敏、选择性地识别次氯酸根离子,其检测下限为0.96μmol/L,并将该探针应用于实际水样中次氯酸根离子含量的检测,在自来水、雨水中的回收率均大于84%。此外,利用质谱和核磁谱图开展的检测机理研究表明,探针的识别机理与次氯酸的氧化脱氢作用和激发态分子内质子转移(ESIPT)过程破坏有关。     

应用光敏生物素标记探针检测杂交瘤细胞中小鼠白血病病毒

采用BamHⅠ酶切和琼脂糖凝胶电泳技术，从重组质粒pSF11中回收5kb小鼠白血病病毒（MuLv）DNA片段，用光敏生物素标记制备DNA探针，采用斑点杂交法检测杂交癌细胞，McAb纯品以及SP2／0细胞中的MuLv。结果表明，此探针特异性好，灵敏度可达25pg。在检测的13株杂交瘤细胞和2株SP2／0细胞中分别有5株和1株为MuLv阳性，在McAb纯品中未查出MuLv。     

英国装备采办技术管理研究

装备采办过程是将科学技术物化为武器装备的过程,技术管理是实现装备采办目标的重要手段。全面介绍了英国装备采办技术管理的基本原则和主要过程,并对技术成熟度水平和系统成熟度水平的应用方法进行了重点分析。     

宽带高增益E型天线设计

该文介绍了一种宽带高增益的E型天线,该天线以空气为介质,通过采用L型探针耦合馈电,贴片与接地板之间可以用塑料杆或泡沫块支撑。馈线通过激励一金属片后,形成L型探针,实现容性耦合,达到激励天线的目的。该天线结构简单。天线在驻波比小于2时,相对带宽达到了41%,可适用于数字通信系统、IMT-2000、无线局域网等无线应用系统,最大增益可达7.52dBi。     

光纤色度测量中的非线性误差的补偿方法

在传统的色度测量中,物体反射光容易受到外界干扰.为了解决干扰引起测量精度下降的问题,把光纤做成的探头用于光能的收集与传输.但是,由于光纤对光谱非线性衰减的影响而使颜色的测量产生畸变.文中采用傅立叶变换对光谱非线性衰减进行校正.实验中,利用高压汞灯产生的特征波长,测得系统的测色波长误差不大于0.2nm.通过对标准色卡的颜色测定,和标准值相比较,色坐标误差小于0.01.实验结果表明,这种带有光纤探头的测色系统测色波长精度高,并有良好的重复性,能较好地改善系统的测色性能.