Effect of incipient removal of hydrogen through palladium membrane on the conversion of methane steam reforming: Experimental and modeling

This paper presents a mathematical model based on the reaction rate expressions to describe the displacement of methane conversion in the steam reforming. The effect of several parameters including weight hourly space velocity (WHSV), load-to-surface ratio, reaction pressure, hydrogen partial pressure in permeate side and reaction temperature were investigated. Simulation and experimental results showed that a conversion higher than 80% could be achieved in a palladium membrane reactor at reaction temperature of 500 °C relative to 850 °C in a conventional fixed bed reactor (FBR). Besides, the yield of CO (<2%) in membrane reactor was much lower than that (>50%) in the FBR, which indicated the significant depression of CO production in use of membrane reactor.     

软弱破碎围岩隧道二衬施作的合理时机判别研究

为了合理判别软弱破碎围岩隧道的二衬施作时机,结合工程实践,通过洞室拱顶沉降和边墙变形收敛的现场监控量测,提出了利用围岩-初支系统变形实测数据判别软弱破碎围岩隧道二衬施作合理时机的考虑支护是否保守的五级速率比值法并研发了相应的软件,并通过工程实例进行了成功验证。研究表明：1研制的软件操作具有界面简洁、友好,以及操作简单易用的特点,具有测点围岩-初支系统位移和收敛的现场监测数据的录入、储存、修改和管理等功能,能方便地进行软弱破碎围岩隧道的二衬合理时机判别;2通过工程实例验证分析表明,提出的方法是可行的,与现行的二衬时机选择的方法本质上是相同的,但更加具有可操作性,研究成果可以为同类型隧道的二衬时机选择提供可资借鉴的方法。     

The effect of nitrogenous fertilizers on the nitrification of forest soils

The effect of fertilization with urea and ammonium nitrate on nitrogen mineralization was studied in a series of laboratory incubation experiments. The samples (humus layer) were collected from field experiments with different applications of fertilizers during a period of 11–14 years. The nitrogen fertilization influenced some chemical properties of the humus layer such as pH, N-Kjeldahl content and the content of inorganic nitrogen, especially in the samples from North Sweden. Nitrate nitrogen was formed in humus samples classified as non-nitrifying in several cases, usually after urea fertilization.     

预应力片材加固负载RC梁受弯承载力分析

分析有初始弯矩作用时,预张纤维片材粘贴加固混凝土梁中加固材料相对该处混凝土滞后应变或超前应变的计算方法和纤维片材中有效预应力的取值;对预应力FRP粘贴加固梁构成的复合截面,分析各种可能应变组合下的受弯极限状态,给出两大弯曲破坏类型(分别由片材拉断和混凝土压碎引发)的界限判别条件和极限承载力计算表达式.试验分析表明,极限承载力试验值与计算值比值的均值为0.99,变异系数为0.047.     

考虑初始弯曲矩形薄壁钢管砼柱管壁屈曲分析

实际工程中的钢管都是有初始弯曲的,初始弯曲的存在会降低薄壁钢管混凝土柱的承载力.采用能量法对具有初始弯曲管壁的屈曲性能进行了分析,分析结果表明,初始弯曲的存在会使管壁的宽厚比降低30%左右.     

高压旋喷桩复合地基承载特性的有限元分析

结合工程实际,运用大型有限元分析软件ANSYS分析了不同桩长、不同桩土模量比和不同桩间距情况下高压旋喷桩复合地基的承载特性.结果表明,该地基存在有效桩长,当桩土模量较合适时,该地基能够发挥最大作用;同时运用ANSYS优化功能,得出了最优桩长、最优桩体弹性模量和最优桩间距,为实际工程提供一些参考.     

多核程序交互理论及应用

多核处理器上共享缓存使用效率,即程序局部性是影响并行程序性能的关键因素之一。提出了以足迹为基础的局部性理论。介绍了缺失率、重用距离和足迹之间的转化关系,并利用足迹可组合性特征建立了并行程序局部性预测模型。     

倒谱距离和短时能量的语音端点检测方法研究

在讨论传统倒谱距离语音端点检测方法不足的基础上,提出了一种基于倒谱距离和短时能量的语音端点检测改进方法。基于倒谱距离的单参数端点检测方法在高信噪比环境下效果较好,然而在低信噪比的环境下其端点检测性能急剧下降。通过分析倒谱距离和短时能量各自的端点检测特性,建立了一种结合二者特点的双参数判决准则,在保证运算量没有显著增大的前提下提高了端点检测的准确率。仿真实验结果表明,新方法相对于基本倒谱距离端点检测方法,在低信噪比的高斯白噪声环境下端点检测性能有较明显提高。     

一种白光测速仪在热锯区域中的应用

阐述白光测速仪的工作原理及优缺点,介绍其在莱钢大H型钢生产线热锯区域的应用.     

Adaptive detectors in the Krylov subspace

The validity of the application of the Krylov subspace techniques in adaptive filtering and detection is investigated. A new verification of the equivalence of two well-known methods in the Krylov subspace, namely the multistage Wiener filters （MWF） and the auxiliary-vector filtering （AVF）, is given in this paper. The MWF and AVF are incorporated into two well-known detectors, namely, the adaptive matched filter （AMF） and Kelly＇s generalized likelihood ratio test （CLRT） including their diagonally loaded versions, which form new detectors. Compared to the conventional AMF, CLRT, and their diagonally loaded versions as well as the reduced-rank AMF and GLRT, the probabilities of detection （PDs） of the new detectors are improved especially when the sample support is low. More importantly, the new detectors are robust of the rank selection of the clutter subspace compared to the reduced-rank AMF and GLRT. These new detectors all possess asymptotic constant false alarm rate （CFAR） property.