基于说话人辨识的自上而下听觉显著性注意模型

为体现听觉注意神经信息处理计算机制对听觉场景内容的自动分析与理解功能,本文基于人耳对频率变换的感知特性,结合深度信念网络的说话人辨识与听觉显著模型,提出了一种自上而下的听觉显著性注意提取模型.仿真结果表明:该模型具有可行性,同时在利用深度信念网络的说话人辨识技术中能够有效地凸显目标说话人的显著度.     

二次有理Bèzier曲线曲率单调条件的研究

文中研究并推导出了二次有理 Bèzier曲线的曲率单调条件 .研究结果表明 ,有理 Bèzier曲线比 Bèzier曲线的曲率单调条件具有更大的自由度 .对于任意的三个控制顶点 ,只要两控制边的夹角不小于 90度 ,必定存在一族曲率单调的二次有理 Bèzier曲线 .二次有理 Bèzier曲线不仅可表示曲率单调的抛物线段 ,还可表示曲率单调的椭圆弧和双曲线段 ,这取决于权因子的取值 .     

基于混合粒度冲突检测的事务工作流调度算法

事务工作流由若干个平面事务组成,其执行满足松弛原子性.由于组成事务工作流的平面事务具有不同的完成特性,为了防止不可串行化的执行,现有的调度算法通常只允许一个活动工作流执行不可补偿事务,这大大限制了并发度.定义了基于事务类型和事务实例两种粒度的冲突关系,并提出了一种基于这两种粒度冲突检测的调度算法,保证了并发事务工作流的可串行化和可恢复执行.该算法从两个方面提高了并发度:一方面通过事务实例之间(细粒度)的冲突检测减少了工作流冲突的概率;另一方面通过事务类型之间(粗粒度)的冲突预测,允许多个将来不冲突的工作流执行不可补偿事务.     

Assessment of thermochemically stable apatite La10(SiO4)6O3 as electrolyte for solid oxide fuel cells

Apatite-type lanthanum silicate with a formula of La₁₀(SiO₄)₆O₃ is a potential candidate electrolyte for SOFC system because of its high ionic conductivity and low activation energy. Pure La₁₀(SiO₄)₆O₃ powder was prepared by solid state reaction and using a suitable thermal pretreatment (1000 °C/5 h) of the as-purchased La₂O₃ powder. Materials characterization, thermal behaviors, and electrical properties of La₁₀(SiO₄)₆O₃ samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and two-point probe DC conductivity. A pure La₁₀(SiO₄)₆O₃ pellet was prepared at the sintering process of 1600 °C and 2.5 h with a high relative sintered density of 96.91%. The existence of secondary phases in La₁₀(SiO₄)₆O₃ pellet resulted in a lower conductivity than that of pure La₁₀(SiO₄)₆O₃ pellet. Eight-hour reduction-resistant stability tests under reducing atmosphere at the elevated temperature of pure La₁₀(SiO₄)₆O₃ prepared in this study shows a good thermochemical stability as compared to the well-developed 8 mol% Y₂O₃ stabilized ZrO₂ (8YSZ).     

数控三工位大型高压瓷套修坯机组的研制

研制出一种适用于等静压干法加工工艺的新型结构数控三工位大型高压瓷套修坯机组。机组的三台加工设备采用星形排列,上坯机设在机组中心,实现各个加工机床间坯件的换位和定位。电气控制系统采用编程控制器(PLC),实现手动和自动控制。实践证明,该机组的噪音为71dB,粉尘泄漏量为33.1m g/m 2,实际产量为每天两班生产11根坯件,达到了设计要求。     

热工微机保护系统GPS授时的研究和应用

热工微机保护系统是具有毫秒级事故追忆功能的PLC保护系统。GPS授时装置能全天候、实时地接收GPS卫星发出的信号,获取精确的导航定位信息和精确的时间信息。通过与GPS授时装置通讯,读取GPS卫星标准时间,定期校正PLC控制器,使PLC时钟与标准时间始终保持同步,从而进一步完善提高毫秒级事故追忆功能。     

SNS collaborative learning design: enhancing critical thinking for human–computer interface design

Universal Access in the Information Society - In many cases, classrooms seem to be functioning as well as ever, though the challenges and expectations have changed quite dramatically. This study...     

Effect of Pt/TiO2 characteristics on temporal behavior of o-cresol decomposition by visible light-induced photocatalysis

Platinum deposited TiO(2) films were prepared on quartz substrates by dip-coating process for the photodecomposition of o-cresol. The characteristics of Pt/TiO(2) and the temporal behavior of o-cresol decomposition by Pt/TiO(2) photocatalysis under visible light irradiation were investigated. Platinum deposited on TiO(2) photocatalysts was characterized by Brunauer-Emmett-Teller (BET) surface area measurement, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), diffuse reflectance UV-Vis spectra (DRS) and photoluminescence (PL) emission spectra. The results indicated that the deposition of platinum on TiO(2) promoted the optical absorption in the visible region and made it possible to be excited by visible light. The decomposition rate of o-cresol under visible light irradiation from a fluorescent lamp was enhanced to noticeably extents for experiments conducted with Pt/TiO(2) containing platinum up to 0.50wt% platinum because of the presence of Ti(3+) resulted from the platinum deposited on the TiO(2) surface; and the formation of Schottky Barrier between platinum and TiO(2) preventing the recombination of electric holes and electrons. Specifically, the reaction rate of o-cresol photodegradation at pH 9 using the 0.50wt% Pt/TiO(2) was 4.8 times than that of using pure TiO(2). The intermediates identified by GC/MS spectroscopy during the photocatalytic oxidation of o-cresol. The proposed kinetic model could be adequately applied to describe the temporal behavior of the o-cresol decomposition with and without the dosage of Pt on TiO(2) in aqueous solution by UV/TiO(2) process.     

Effect of Fiber Bridging Stress on the Fracture Resistance of Silicon-Carbide-Fiber/Zircon Composites

The room-temperature fracture-resistance behavior ( R -curve) of unidirectional silicon-carbide-fiber-reinforced zircon-matrix composites has been studied experimentally and numerically. The composites showed strong rising R -curve behavior from experimental results that used in situ crack-length measurements taken via optical microscopy as well as the compliance method. A numerical calculation, based on the available models, then was performed to determine the bridging-stress function from the experimental R -curve. In addition, the effect of the residual stress and constituent properties on the bridging-stress function also has been considered in the numerical calculations. These results have indicated that the bridging-stress function, which controls the fracture resistance of ceramic composites, can be obtained from the carefully measured R -curve.