Speaker normalization for chinese vowel recognition in cochlear implants

Because of the limited spectra-temporal resolution associated with cochlear implants, implant patients often have greater difficulty with multitalker speech recognition. The present study investigated whether multitalker speech recognition can be improved by applying speaker normalization techniques to cochlear implant speech processing. Multitalker Chinese vowel recognition was tested with normal-hearing Chinese-speaking subjects listening to a 4-channel cochlear implant simulation, with and without speaker normalization. For each subject, speaker normalization was referenced to the speaker that produced the best recognition performance under conditions without speaker normalization. To match the remaining speakers to this "optimal" output pattern, the overall frequency range of the analysis filter bank was adjusted for each speaker according to the ratio of the mean third formant frequency values between the specific speaker and the reference speaker. Results showed that speaker normalization provided a small but significant improvement in subjects' overall recognition performance. After speaker normalization, subjects' patterns of recognition performance across speakers changed, demonstrating the potential for speaker-dependent effects with the proposed normalization technique.     

Preparation and properties of montmorillonite/organo-soluble polyimide hybrid materials prepared by a one-step approach

Montmorillonite (MMT)/organo-soluble polyimide (PI) hybrids were prepared using a one-step approach. The organo-modified MMT was dispersed in a solution of diphenylether-3, 34,4-tetracarboxylic dianhydride and 4,4-diamino-3,3-dimethyldiphenylmethane. The solution polycondensation followed by a direct solution imidization at 180 °C resulted in MMT/PI hybrid solutions. From wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) results, the MMT is basically exfoliated in the hybrid films cast from the solutions when the MMT content is below 5 wt%. Further increase in the MMT content leads to severe aggregation. The properties of a MMT/PI hybrid are significantly dependent upon the MMT content. When the MMT content is below 6 wt%, the introduction of the MMT leads to strengthening and toughening to the PI matrix at the same time. The introduction of the MMT also results in improved thermal stability, marked decrease in coefficient of thermal expansion, slight increase in glass transition temperature and increase in modulus.     

裂缝介质中石油运移模拟实验研究

系统地介绍了裂缝介质中油-水两相运移光蚀刻物理模拟实验所采用的实验模型设计方法、应考虑的因素、模型几何参数确定、拓扑结构、模型渗透率等宏观特征参数的定量化以及流体参数的选择方法。实验结果表明:①宽缝对窄缝具有极强的流动屏蔽作用,窄缝在油气运移中几乎不起作用;②在运移动力方向与渗透主方向垂直的情况下,当原油粘度达到一定数值时,沿驱替方向上运移的速度反而会更快一些。     

长期运行的X20CrMoV12.1钢主蒸汽管性能劣化研究

为评估在役X20CrMoV12.1钢结构完整性和安全可靠性,详细研究了X20CrMoV12.1钢主蒸汽管在550℃、13.7MPa作用下,经长期高温时效1.6×105h后的机械性能及其显微组织的变化。试验样品从在役弯管上截取;在室温和550℃高温下分别对管道纵向及环向的机械性能如冲击、拉伸及硬度等进行了测定;用金相、能谱、扫描电镜和透射电镜等方法,观察表征了管材的显微组织结构的变化及其劣化状况。试验结果表明,管材的冲击性能下降明显,常温下呈脆性状态;试样的断口分析和结构表征进一步显示:管材显微组织劣化显著、蠕变损伤特征明显、晶界碳化物粗化严重及晶内粗大的碳化物沉淀生成。     

萨尔图北一、二排西上返区块采出程度分析

大庆油田萨尔图中部开发区北一、二排西部区块主力油层葡萄花油层Ⅰ组结束聚合物驱油后即将上返到萨尔图油层萨Ⅱ10～萨Ⅲ10单元层注聚合物,这个区块是大庆油田第一个二类油层聚合物工业驱区块,其注聚合物前的采出程度的准确标定关系到大庆油田二类油层聚合物工业驱的效果评价和进一步推广应用.通过对该区块的动态、静态资料的四种不同计算采出程度方法优缺点加以分析对比,认为"静态资料法"比较合理,并将该方法计算结果标定为区块注聚合物前采出程度.     

助滤剂在超细轻质CaCO_3过滤中的应用

用比阻法考察添加了有机高分子 L助滤剂的超细轻质 Ca CO3悬浮液过滤的难易。     

稀土氧化物和硫酸盐对聚氯乙烯热稳定作用的研究

本文着重研究了不同稀土无机化合物对聚氯乙稀热稳定性的影响，并对其作用机理进行了初步探讨。     

2-苯亚甲基肼基苯甲酸-4-磺酸的合成研究

以2-氨基苯甲酸-4-磺酸为原料,经过重氮化,还原反应生成-2-羧基苯肼-5-磺酸,再与苯甲醛缩合,合成2-苯亚甲基肼基苯甲酸-4-磺酸。反应总收率约 90%。产物结构经 H1NMR和MS表征。     

Preparation of PS/TiO2 core-shell microspheres and TiO2 hollow shells

PS/TiO₂ core-shell microspheres were prepared by a hydro-thermal method at 105°C. Different-sized PS/TiO₂ core-shell microspheres were obtained with various PS cores, which were prepared by emulsion polymerization and seeds polymerization. Furthermore, intact hollow TiO₂ shells with different shell thickness were obtained by calcining PS/TiO₂ core-shell microspheres at 600°C. Light scattering of core-shell microspheres and hollow shells was tested.