撞击流-旋转填料床萃取器传质性能研究

以磷酸三丁酯(煤油)-苯酚-水为试验体系，研究了IS—RPB萃取器的传质性能。在研究主要操作参数对萃取级效率影响的基础上，确定了最适宜的操作条件，得到了97％以上萃取级效率。试验结果表明，撞击流-旋转填料床萃取器是一种新型快速高效的萃取设备。     

旋转注射式反应注射成型技术混合方式剖析

为了克服反应注射成型技术混合方式存在的缺点，新近出现了一种旋转注射式－ＲＩＭ技术。该技术采用低速旋转注射剪切层流混合方式，具有能耗低，混合效果好，应用广泛等特点，是一种很有应用潜力的新技术，文内对该技术的混合方式进行了简要剖析。     

MIMU辅助旋转弹丸GPS接收机跟踪环路设计

在GPS导航定位系统中,多普勒频移直接影响接收机的跟踪性能.为了克服多普勒频移的影响,对高速旋转的弹载单天线GPS接收机跟踪环路进行了研究.分析了弹丸旋转产生的复杂多普勒频移的影响因素,给出了多普勒频移的数学模型,提出采用MIMU估计多普勒频移的方法设计二阶载波跟踪环路,建立了环路的模型,并对环路的跟踪性能进行了MATLAB仿真.结果表明:MIMU辅助的跟踪环路与无辅助的跟踪环路比较,带宽窄,能有效地抑制噪声干扰,较好地实现了对旋转信号的跟踪.     

水工隧洞支护特性研究

以某水工隧洞为工程背景,采用D-P屈服准则,考虑了水应力的影响范围,利用ANSYS软件进行了水工隧洞三维弹塑性有限元计算分析.分别研究了衬砌支护材料的选择对隧洞稳定性的影响、开挖过程和应力旋转对支护时机选择的影响.计算结果表明:随着衬砌支护材料弹性模量的提高,隧洞顶部和底部分别有上弹和下沉的趋势,隧洞的稳定性有所提高;隧洞的开挖步骤和应力旋转对衬砌支护施做时机的选择有重要影响.     

基于广义AIC和RPC的OFDM航空信道估计算法

文章通过对航空信道的分析,指出其稀疏信道特征,使用普通算法对此信道进行信道估计会引入高阶矩阵运算,为加快收敛速度、降低实现难度,文中提出了一种利用GAIC(generalized Akaike information criterion)准则和RPC(repeated phase-rotated Chu)训练序列的OFDM航空信道LS(1east squares)估计方法,该方法利用GAIC准则确定信道模型的阶次及抽头位置,为减小信道估计的运算复杂度,引入RPC序列作为训练序列,既满足了LS(least squares)估计,又大大简化了计算复杂度.文章针对具体应用给出文中算法的性能仿真结果,证明了此算法可避免高阶矩阵运算,节约了大量权值可忽略抽头所引入的资源占用和计算量,且显著减小估计误差,可更好跟踪快变的稀疏信道.     

A recognition method of vibration parameter image based on improved immune negative selection algorithm for rotating machinery

To overcome the limitations of traditional monitoring methods, based on vibration parameter image of rotating machinery, this paper presents an abnormality online monitoring method suitable for rotating machinery using the negative selection mechanism of biology immune system. This method uses techniques of biology clone and learning mechanism to improve the negative selection algorithm to generate detectors possessing different monitoring radius, covers the abnormality space effectively, and avoids such problems as the low efficiency of generating detectors, etc. The result of an example applying the presented monitoring method shows that this method can solve the difficulty of obtaining fault samples preferably and extract the turbine state character effectively, it also can detect abnormality by causing various fault of the turbine and obtain the degree of abnormality accurately. The exact monitoring precision of abnormality indicates that this method is feasible and has better on-line quality, accuracy and robustness.     

Effect of low-frequency rotary electromagnetic-field on solidification structure of continuous casting austenitic stainless steel

To understand the solidification behavior of austenitic stainless steel in rotary electromagnetic-field, the influence of low-frequency rotary electromagnetic-field on solidification structure of austenitic stainless steel in horizontal continuous casting was investigated based on industrial experiments. The results show that the solidification structure of austenitic stainless steel can be remarkably refined, the central porosity and shrinkage cavity can be remarkably decreased, and the equiaxed grains zone are enlarged by means of application of appropriate low-frequency electromagnetic-field parameters. The industrial trials verify that the stirring intensity of austenitic stainless steel should be higher compared with that of plain carbon steel. Electromagnetic stirring affects the macrostructure even if the average magnetic flux density of the electromagnetic stirring reaches 90 mT (amplitude reaches 141 mT) with the frequency of 3–4 Hz. Due to a higher viscosity, rotating speed of molten stainless steel is 20%–30% lower than that of molten carbon steel in the same magnetic flux density. Foundation item: Project(CSTC2007BB4216) supported by the Natural Science Foundation of Chongqing, China     

基于湍流自旋理论的二维方腔旋转流动的数值模拟

基于湍流自旋理论对旋转方腔内不可压流体的流动进行了二维数值模拟,用有限容积法在交叉网格上对控制方程进行离散,采用SIMPLEC算法进行计算,对流项的离散方面采用了延迟修正的QUICK格式,最后采用二维的TDMA算法进行迭代求解,并对边界条件处理采用了Block块技术.同时与经典理论即Navier-Stokes（N-S）方程的模拟情况做了比较.得出下列结论：N-S方程表明方腔旋转时内部流体只会作刚体旋转;而自旋模型表明该类流动具有不平凡性和不稳定性：即流体的内聚力不足以使流体跟随固体边界作刚体运动,旋转边界必然在流体中诱导出小尺度耗散涡旋,这些小尺度涡旋在固壁附近组织出正负相间的拓扑缺陷（涡旋场强）,这一流体定向奇性会与速度场耦合,并容易形成复杂的大尺度的涡旋运动.     

融合复小波特征和局部二值模式的纹理聚类

为了解决图像检索中聚类问题,对图像作双树旋转复小波变换,再对变换后的系数通过广义高斯模型建模后,计算Kullback-Leibler距离;对图像采用局部二值模式,计算图像之间的对数似然距离.将这2种距离采用事先计算得到的加权因子进行融合得到新的距离.在此距离的基础上构建邻接矩阵,对邻接矩阵采用谱聚类的方法进行聚类运算.实验证明,由于双树旋转复小波变换和局部二值模式之间存在互补性,在聚类过程中将2种特征距离结合起来,能够有效地提高聚类的正确性.     

满速率全分集的准正交空时分组码及性能分析

正交分组编码(OSTBC)因其获得全分集和简单的译码算法在无线通信中得到了广泛的应用。但对于复信号的星座图,速率为1的正交设计仅存在两根发射天线中。为能在任意阵列天线应用发射分集的理论,一种可行的方法就是放宽码字间的正交性,利用准正交设计(QOSTBC)来实现满速率,译码时仍采用最大似然译码算法(ML)。但这种准正交设计不能达到全分集,为此,本文对一些符号的星座图利用旋转来实现满速率全分集的方法作了一些初步的讨论,并通过计算机仿真说明理论分析的正确性。