胃食管反流病误诊为呼吸道疾病分析

胃食管反流病(gastroesophageal reflux disease,GERD)常出现呼吸系统症状,使临床诊断困难,甚至误诊为呼吸道疾病.常因误诊而延误诊治,我院2006年6月～2010年7月共收治GERD35例,其中以呼吸道症状为突出表现者18例,均曾在外院或本院误诊为呼吸道疾病,现分析误诊原因如下.     

利用自适应傅里叶分解的非平稳无线信道的时频表示

针对非平稳Clarke无线信道模型的时域冲激响应的性能分析需求,利用自适应傅里叶分解,引入了一种非平稳无线信道的时频表示方法和信道函数的重构表示,并给出了信道的单分量表示式、时间频率分布以及能量谱密度。在高速移动、快速时变环境下进行仿真,结果表明,本文提出的非平稳无线信道的表示方法能克服STFT、小波变换等相关方法的缺点,提高了无线信道时频表示的准确性,降低了信道的重构误差。      

Properties of La0.9Sr0.1MnO3 and tourmaline compound catalytic materials for methane combustion

A novel catalytic material Lao.9Sr0.1MnO3 and tourmaline compound catalytic material was synthesized in the base of traditional catalytic material La0.9Sr0.1MnO3 which exhibited excellent catalytic activity for methane combustion. Different contents of toumaaline were added to give a series ofLa0.9Sr0.1MnO3 and tourmaline catalytic material through a sol-gel method. Samples above were characterized and analyzed by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Brunauer-Emmett-Teller method （BET）, temperaalre programmed reduction （TPR）, catalytic activity test and contact angle test. The as-prepared sample with 2% （m/m） tourmaline showed good homogeneity surface morphology and displayed the optimal catalytic activity. The light-off temperature reduced by 10 ℃ and the T90 decreased by 15 ℃. In addition, the mechanism of the reinforcement of catalytic activity was explored.     

Effect of tourmaline additive on the crystal growth and activity of LaCoO3 for catalytic combustion of methane

LaCoO3/tourmaline was prepared as catalysts on the methane catalytic combustion. As additive tourmaline, its effect on crystal growth and catalytic activity of LaCoO3, were investigated via X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), H2-temperature programmed reduction(H2-TPR) and catalyst evaluation techniques. SEM and TEM indicated that the spontaneous polarizability of tourmaline made LaCoO3 particles grow dispersedly on tourmaline, alleviated the agglomeration and exposed more reactive sites. It was a main influence leading to the improvement of catalysts activity, exposed via catalyst evaluation device. Among the different additive proportion of compound samples, the 2% tourmaline added LaCoO3 showed an obvious enhancement activity compared to non-tourmaline sample—the light-off temperature was 454 °C and CH4 reached the full conversion at 563 °C.     

基于ISO的随钻磁力计误差补偿

针对随钻测量(MWD)中,微机电系统(MEMS)磁力计测量地磁数据误差大,导致磁方位角解算精确度低的问题,提出改进技能优化(improved skill optimization, ISO)的磁力计误差参数估计方法。首先根据磁力计输出特性建立多参数误差模型,根据当地地磁矢量与磁力计输出矢量的模值关系,通过最小化原则构造非线性误差目标函数,重力矢量和磁场矢量之间的点积值为固定值作为约束函数,采用SO算法进行寻优。由于磁误差源多估计难度大,在SO基础上提出ISO算法,采用Tent混沌反向学习初始化策略改善初始种群的随机性,保留最优解的同时增加磁误差参数解空间的多样性。引入自适应技能强度因子,并增加成员间技能交叉规避局部最优,改善ISO磁误差参数寻优技能步长,减小算法运行时间,优化全局搜索能力,提高磁力计误差补偿精度。最后通过转台实验和模拟钻进实验验证ISO方法补偿性能,通过与SO算法和PSO算法对比,实验结果表明该算法对磁力计误差参数优化效果显著,计算出的地磁模值误差范围减小至±0.2μT,方位角绝对误差均值降至2.1°,说明了参数优化后磁力计输出误差明显减小,该方法可以有效提高MEMS磁...     

随钻测量钻具重力加速度提取方法

针对随钻测量(MWD)中钻具重力加速度受振动干扰大引起的井斜角解算严重失真问题，提出基于联邦自适应无迹卡尔曼滤波(FAUKF)的钻具重力加速度提取方法。首先，建立无重置结构的联邦重力信息融合提取框架，选取基于陀螺仪数据的递推重力值作为联邦滤波的公共参考值，分别与解耦的地磁数据观测的重力加速度组合作为子滤波器1,与加速度计数据观测的重力加速度组合作为子滤波器2。然后，对子滤波器的重力状态进行无迹卡尔曼滤波(UKF)算法，期间根据地磁数据观测重力值的抗振性优于加速计的特性，设计子滤波器2对应的抗振因子，再根据陀螺仪短时精度高的输出特性，找到基于陀螺仪数据解耦的地磁参考斜率值，来设计子滤波器1对应的抗磁因子，提升子滤波器性能，接着用自适应开窗因子来确定开窗估计法则中的开窗值，调节新息协方差，通过对新息协方差的估计实现子滤波器量测噪声协方差的实时估计，提高无迹卡尔曼滤波算法精度，进而得到可靠的重力信息局部自适应估计值。最后通过联邦信息融合，进一步得到重力信息的全局估计。通过模拟钻进和实钻实验结果表明，FAUKF算法和FKF算法相比，井斜角误差减小了±1.9°,FAUKF算法下的井斜角误差可控制...