One step from nanofiber to functional hybrid structure: Pd doped ZnO/SnO2 heterojunction nanofibers with hexagonal ZnO columns for enhanced low-temperature hydrogen gas sensing

In this paper, a novel hybrid structure of Pd doped ZnO/SnO₂ heterojunction nanofibers with hexagonal ZnO columns was one step synthesized from electrospun precursor nanofibers. Due to the synergistic effect of hexagonal ZnO, SnO₂ and Pd, the structure exhibited excellent hydrogen (H₂) gas sensing properties. At low-temperature of 120 °C, the response (R_a/R_g) to 100 ppm H₂ gas exceeded 160, the response/recovery time was only 20 s and 6 s respectively and the limit of detection was only 0.5 ppm. Meanwhile, it also had good selectivity for H₂ gas and excellent linearity. In addition, the materials were characterized by XRD, FESEM, HRTEM, XPS, and the synthesis mechanism and gas sensing mechanism were proposed.     

多媒体英语教学利弊及对策

依据教学实践调查,对多媒体英语教学的利弊进行初步分析并对不足之处提出应对措施.多谋体英语教学既有传统教育无可比拟的优越性,也存在缺憾和不足.     

Accelerated Manhattan hashing via bit-remapping with location information

Multimedia Tools and Applications - Hashing is a binary-code encoding method which tries to preserve the neighborhood structures in the original feature space, in order to realize efficient...     

基于DE1-SoC的磁性介质显示系统设计与实现

针对常规平面成像技术表现形式单一,容易视觉疲劳等问题,提出一种新型的基于FPGA/ARM异构双核控制的磁性介质显示系统,实现磁性介质的立体动态成像;本系统通过在Altera DE1-SoC的Linux平台上构建Lighttpd轻量级Web服务器和设计开发功能程序、底层驱动程序、自定义IP核和Verilog逻辑译码程序来实现该显示系统的软硬件开发;本系统具有网络设备跨平台控制能力、磁流体精确控制能力以及多种样式的汉字和图案显示能力;大量实验表明该系统能够通过控制磁流体完美的表现出立体书法、绘画图案,且系统运行稳定可靠。     

Potential Clogging and Dissolution Effects During Artificial Recharge of Groundwater Using Potable Water

To avoid the water quality deterioration that are caused by artificial recharge (AR) of groundwater, potable drinking water has been used as one of the source water for AR to control the side effects caused by the over-exploitation of groundwater. Chemical clogging problems can still be caused by certain chemical components, especially Fe and Al, and a lower concentration of these elements can cause a notable decrease in hydraulic conductivity at the top layer of the infiltration medium. Some components in AR source water can be obstructed by the clogging layer, leading to a change in water quality. The accumulation of total suspended solids (TSS) at the clogging layer can cause physical clogging and worsen the degree of chemical clogging. Although clogging and the related change in water quality were the dominant issues that affect the infiltration rate and health risks during the AR process, the dissolution of the aquifer matrix should also be taken into account. This dissolution contributed to not only the hydraulic conductivity of the infiltration medium but also the potential change in water quality during the aquifer recharge, storage and recovery processes.     

一种在LTE-Advanced载波聚合下降低CM的方法

3GPP LTE采用OFDMA作为物理层多址接入技术。而峰值引起的功率回退是OFDM技术的主要问题,因此在LTE中,采用CM(立方度量)来度量功率回退。LTE-Advanced中为了提升峰值速率引入了载波聚合技术,多个成员载波的引入可能会带来CM的提升。主要介绍一种载波聚合下降低由于重复导频引起的CM过高的方法。该方法不仅能够在多个成员载波情况下有效地降低CM,并且可以将复杂度和处理时延控制在较小范围内。     

一种有效压缩十字阵二维角估计计算量的方法

针对平面阵在二维方向角估计中运算量大、影响系统实时性的问题.利用十字阵为两个直线阵构成的特点,提出了一种新的十字阵二维谱估计方法.通过间接求解,将二维方向角估计转化为两个独立直线阵的一维角估计.此方法无需二维谱峰搜索,大大减少了运算量,提高了阵列的分辨力.计算机仿真验证了该方法的有效性.     

鄂尔多斯盆地东南缘长3油层组成岩储集相

鄂尔多斯盆地东南缘长3油层组为低孔、特低渗透储层,为明确其成岩储集相类型和优质储层的控制因素,根据铸体薄片、扫描电镜、电子探针、X衍射等资料分析,对其成岩作用特征和成岩储集相类型进行了系统研究。结果表明,鄂尔多斯盆地西南缘长3油层组成岩后生作用复杂多变,破坏性成岩作用主要为机械压实、压溶作用及各类自生矿物胶结作用,溶解作用和破裂作用是储层物性改善的主要途径;长3油层组发育4种类型的成岩储集相,其中浊沸石溶蚀次生—原生孔储集相是最有利的成岩储集相,其分布受沉积相带控制,发育在三角洲平原及前缘截削式分流河道中;浊沸石次生孔隙的发育和沉积砂体的分布特征及是优质储层形成的主控因素。     

木片筛余物高得率半化学法清洁制浆技术研究

以太阳纸业备料车间木片筛选碎料（筛余物）为原料,对其烧碱法半化学制浆的实验室工艺和生产试验进行了研究。结果表明,筛余物采用半化学法制浆可获得较高得率和环压强度的纸浆,且用碱量对纸浆性能有显著影响。相对8%NaOH （相对于绝干原料）化学预处理,采用14%NaOH化学预处理结合两段浆浓22%的高浓磨浆工艺,所制半化学浆抄造浆张的裂断长和环压指数分别达2.89 km和9.76 N·m/g,是前者的1.9倍和1.2倍,而且优于现用国内OCC废纸浆抄造浆张;生产试验得到的浆张性能指标与实验室相吻合,其中紧度和环压强度分别达到GB/T 13023—2008瓦楞芯（原）纸AA级和A级优等品要求。     

入风口配置对SLK涡流选粉机预处理系统影响的数值模拟

物料分级效率及分级精度是提升选粉机性能的关键因素.以SLK选粉机为研究对象,通过对单口、对口和四口入风配置的数值模拟总结了入口配置方案对送料筒内部流场特性的影响.在颗粒受力分析的基础上提出环形入风,以此优化了预处理系统的流场特性.结果 表明,入风口配置对送料筒内流速大小、流速分布以及湍流发展等影响较大.更多面的入口能够减少气流对冲、剪切及溢出等负面行为,从而获得稳定、高速、均匀的流场特性.颗粒在散料锥处的受力分析理论上说明了流场稳定性对颗粒均匀、稳定传输的重要作用,并阐明环形入风的潜在优势.此外,对散料锥处代表性水平线上的数据进行监测,从而评价环形入风配置的应用前景,为水泥、矿渣等相关工艺提供理论支撑及升级策略.