用磺化泥炭吸附铬(Ⅵ)的热力学特性研究

在静态条件下,研究了水溶液中磺化泥炭吸附铬(Ⅵ)的热力学特性,测定了不同温度下磺化,泥炭吸附铬(Ⅵ)的吸附等温线.结果表明,在稀溶液中磺化泥炭吸附铬(Ⅵ)基本符合Langmuir模型,由于磺化泥炭的微孔结构和表面存在含氧功能团的吸附中心,溶液中的铬(Ⅵ)主要以HCrO-4的形式被磺化泥炭吸附,导致水分子的脱附及H 的产生,从而使热力学函数△So增加.     

应用水化硅酸盐纳米粉体制备块体材料

以磨细生石灰和硅质原料的混合物为前驱物,采用动态水热合成方法制备了水化硅酸盐纳米粉体.借助SEM、TEM及氮吸附等测试方法,分析了制得的水化硅酸盐粉体的形貌、粒径和比表面积.将制得的水化硅酸盐纳米粉体压制成块状固体.采用正交设计方法研究了成型压力、水泥掺量、纤维掺量、聚合物掺量等因素对块体材料力学性能的影响.结果表明:由该粉体压制成的块体材料立即具有强度和耐水性,且表观密度低;成型压力是影响其力学性能最显著的因素.     

天然气超声流量计健康状态评价方法初探

目的天然气计量用超声流量计性能诊断主要采用设定参数阈值的诊断方法,为降低误报、漏报等情况,建立了基于生成对抗神经网络(generated adjoint neural network,GAN)和高维非线性无监督学习的超声流量计健康状态系统诊断方法。 方法采用GAN对原始数据进行学习、生成和扩充,保障超声流量计健康状态诊断建模的数据基础,提取超声流量计在运行过程中的健康状态参数并对其进行时序分析,采用高维非线性无监督聚类学习方法,结合超声流量计失效模式分析,对超声流量计设备进行在线的健康状态诊断。 结果结合超声流量计工作原理和现场实际采集数据,对生成的故障数据集进行了验证。 结论能够准确识别超声流量计当前状态,显著解决传统阈值法误报率、漏报率高的问题,为超声流量计健康诊断的统一管理与开发给予支撑。      

Distribution of heavy metals during pyrolysis of waste printed circuit boards

The volatilization behavior of Cu, Pb, Sn, Sb, Ni, Zn, Mn, Co, Cr, Cd during pyrolysis of waste printed circuit boards was investigated in a bench-scale fixed-bed pyrolysis system. It was found that volatility of heavy metals increases with operating temperature elevating, and bromine and vacuum have an obvious promoting effect on volatility of most of heavy metals. Over 99% weight of Cu and Ni are still remained in solid residue after pyrolysis, about 20% weight of Sb, Zn and Cd are transfered into liquid and gas during a pyrolysis process at 600 ℃, volatilization fractions of Pb, Sn, Mn, Co, Cr are less than 10% at the same conditions. The contents of heavy metals in liquid and gas products depend on not only volatility of metals, but also their initial contents in printed circuit boards, pyrolysis liquid and gas are primarily contaminated by Cu, Pb, Sn, Sb and Zn, their contents in liquid vary from 10^2 to 10^3 pg/mL, Mn, Co, Cr, Cd were detected only at very low level, less than 10 μg/mL.     

面向服务的无线传感器网络协议架构

分析了目前WSN从研究领域转向工程领域阶段中面临的困难,然后遵循面向服务的思想,以相互间松散耦合的服务单元作为网络协议的基本组成单位,提出了一种非层次结构的WSN网络协议架构,并使用基于Petri网的形式化方法对WSN的服务服务组合和扩展进行建模分析,探讨了服务组合中的一些条件和规则。基于服务的构建,能够较为全面和合理的描述WSN协议架构,并可通过相关服务组合满足WSN多样化的应用需求。     

Observer-based H-infinity output feedback control with feedback gain and observer gain variations for Delta operator system

Considering that the controller feedback gain and the observer gain are of additive norm-bounded variations, a design method of observer-based H-infinity output feedback controller for uncertain Delta operator systems is proposed in this paper. A sufficient condition of such controllers is presented in linear matrix inequality （LMI） forms. A numerical example is then given to illustrate the effectiveness of this method, that is, the obtained controller guarantees the closed-loop system asymptotically stable and the expected H-infinity performance even if the controller feedback gain and the observer gain are varied.     

Clustering-based topical Web crawling using CFu-tree guided by link-context

Topical Web crawling is an established technique for domain-specific information retrieval. However, almost all the conventional topical Web crawlers focus on building crawlers using different classifiers, which needs a lot of labeled training data that is very difficult to label manually. This paper presents a novel approach called clustering-based topical Web crawling which is utilized to retrieve information on a specific domain based on link-context and does not require any labeled training data. In order to collect domain-specific content units, a novel hierarchical clustering method called bottom-up approach is used to illustrate the process of clustering where a new data structure, a linked list in combination with CFu-tree, is implemented to store cluster label, feature vector and content unit. During clustering, four metrics are presented. First, comparison variation （CV） is defined to judge whether the closest pair of clusters can be merged. Second, cluster impurity （CIP） evaluates the cluster error. Then, the precision and recall of clustering are also presented to evaluate the accuracy and comprehensive degree of the whole clustering process. Link-context extraction technique is used to expand the feature vector of anchor text which improves the clustering accuracy greatly. Experimental results show that the performance of our proposed method overcomes conventional focused Web crawlers both in Harvest rate and Target recall.     

超宽带室内修正S—V信道模型的仿真与分析

信道模型是无线通信系统研究和设计的基础.介绍了超宽带室内无线通信信道模型,给出了泊松过程模型、△-K模型、S-V模型以及IEEE802.15.3a模型等典型UWB信道模型的建模方法和特征,针对室内信道多径分量的成簇到达特性提出了修正的S-V信道模型并对其进行仿真.仿真结果表明,该模型能较好的反应UWB信道的特征参数.     

一种基于移动阈值的三色标记算法

针对区分服务中存在的带宽分配公平性问题,设计一种新的基于移动阈值的三色标记算法,该三色标记算法的阈值根据流占用带宽的比例情况自动进行调整,从而提高了网络带宽的公平性分配.实验表明,新的三色标记算法比基于时间滑动窗口的三色标记算法的公平性有一定提高,对提高带宽分配公平性具有一定的实用价值.     

基于Gabor滤波的灰度图像彩色化方法

提出一种基于Gabor滤波的分层次图像彩色化方法.使用Gabor滤波提取图像纹理特征,利用纹理特征将目标灰度图像分割为多个子区域.其中,每个子区域与源参考图像的单个纹理区域相对应,且拥有单调的色彩;分别对子区域进行彩色化,从而降低全局图像彩色化的复杂度.实验结果表明,此方法能抑制图像颜色传输时颜色的丢失,有效地提高彩色化质量.