Performance characteristics of a diesel engine with deccan hemp oil

In this present investigation deccan hemp oil, a non-edible vegetable oil is selected for the test on a diesel engine and its suitability as an alternate fuel is examined. The viscosity of deccan hemp oil is reduced first by blending with diesel in 25/75%, 50/50%, 75/25%, 100/0% on volume basis, then analyzed and compared with diesel. Further blends are heated and effect of viscosity on temperature was studied. The performance and emission characteristics of blends are evaluated at variable loads of 0.37, 0.92, 1.48, 2.03, 2.58, 3.13 and 3.68 kW at a constant rated speed of 1500 rpm and results are compared with diesel. The thermal efficiency, brake specific fuel consumption (BSFC), and brake specific energy consumption (BSEC) are well comparable with diesel, and emissions are a little higher for 25% and 50% blends. At rated load, smoke, carbon monoxide (CO), and unburnt hydrocarbon (HC) emissions of 50% blend are higher compared with diesel by 51.74%, 71.42% and 33.3%, respectively. For ascertaining the validity of results obtained, pure deccan hemp oil results are compared with results of jatropha and pongamia oil for similar works available in the literature and were well comparable. From investigation it has been established that, up to 25% of blend of deccan hemp oil without heating and up to 50% blend with preheating can be substituted for diesel engine without any engine modification.     

面向语义网的中文本体应用研究

自从Protege出现以来,它成为唯一一款支持中文本体构建的工具,而且能够进行可视化操作。目前在部分领域已经构建了中文本体,但是对所构建本体在语义网中的应用缺乏研究。因为本体的应用主要依赖于推理工具,而国内尚无一款专业的基于中文本体的推理机或者推理工具,这阻碍了基于中文本体信息检索的发展。针对中文本体的应用,深入研究了本体在信息检索领域应用的现有技术、方法、工具。文中通过使用Jena开发包对中文本体的应用进行实验,实验表明,利用现有的推理工具等可以实现中文本体在语义网中的应用。     

A revisit to the design of switched observers for switched linear systems with unknown inputs

This paper revisits the problem of designing switched observers for switched linear systems with unknown inputs. By performing a state and output coordinates transformation that decouples the unknown input, a novel piecewise time-varying Lyapunov function is introduced to analyze the stability of the switched error dynamics. Compared with the existing time-invariant Lyapunov function method, the proposed time-varying Lyapunov function method is more suitable to exploit the structural characteristics of switched linear systems. New conditions are derived that guarantee the exponential stability of the switched error dynamics. These conditions are formulated in term of linear matrix inequalities (LMIs). By solving a set of LMIs, the switched observers can be designed. Two numerical examples are provided to illustrate the effectiveness of the proposed method.     

竖向恒载对框架结构动力稳定性影响研究

以框架结构为例,建立了结构动力稳定性分析的基本模型,提出了利用动力响应的敛散性来判断结构动力稳定性的具体方法.通过算例分析,给定不同的竖向恒载值,得到框架结构在水平动力荷载作用下的临界荷载值,结果表明,竖向恒载对动力稳定性有明显影响,但动力临界荷载与相应静力临界荷载的比值变化不大.     

长短桩复合地基设计计算方法探讨

分别从长桩和短桩作用机理两方面阐述了长短桩复合地基的作用机理。以刚性长桩和柔性短桩组合成的长短桩复合地基为例,对常用的长短桩复合地基承载力计算方法之面积加权法和分步叠加法进行了介绍和对比分析,得出两种方法计算结果的一致性,并通过工程实例进行了验证。对长短桩复合地基沉降计算方法之复合模量法和增大系数法进行了介绍,分析了两种计算方法产生误差的原因,给出了一个采用增大系数法计算长短桩复合地基沉降的工程实例,工程实例计算结果与实际观测结果较吻合。建议采用增大系数法计算长短桩复合地基沉降时有必要对加固区桩间土模量增大系数进行适当修正,修正系数的取值范围需通过对大量工程实例进行分析后确定。     

超声波协同超微粉技术辅助酸法提取黑木耳果胶

探讨了超声波协同超微粉技术辅助酸法提取黑木耳果胶的工艺条件。分别考察了超声波辐射强度、液料比、温度、pH值及提取时间等因素对果胶得率的影响,并以此为基础用正交法优化提取黑木耳果胶的工艺参数。结果表明,采用此法从黑木耳中提取果胶的适宜工艺条件为超声波辐射强度70 W/kg、液料质量比40∶1、温度70℃、pH值3.0、提取时间60 mim。在此条件下,木耳果胶得率可达35.45%,与其他方法相比,果胶得率最高。     

厌氧活性污泥PCR-DGGE图谱的优化

针对特种污泥PCR-DGGE图谱的优化一直是微生物分子生态学研究的重点.在反硝化抑制硫酸盐还原菌的研究中,研究厌氧硫酸盐还原污泥和反硝化污泥DNA的提取方法,应用通用引物958F/1401R扩增16S rDNA序列,探讨不同的退火温度对DGGE指纹图谱多样性影响,同时采用时间进程法对DGGE图谱进行优化.结果表明,采用PBS洗涤污泥和超声震荡有利于硫酸盐还原污泥DNA提取;采用958F/1401R为引物时,扩增片段大约500 bp,不同的退火温度对DGGE指纹图谱的多样性影响不显著;采用时间进程法可以很好地再现不同电泳阶段对样品的分离效果,最佳变性剂梯度为40%～60%,在130 V电压下,最佳电泳时间为5 h.     

Bi-level programming model for reconstruction of urban branch road network

Considering the decision-making variables of the capacities of branch roads and the optimization targets of lowering the saturation of arterial roads and the reconstruction expense of branch roads, the bi-level programming model for reconstructing the branch roads was set up. The upper level model was for determining the enlarged capacities of the branch roads, and the lower level model was for calculating the flows of road sections via the user equilibrium traffic assignment method. The genetic algorithm for solving the bi-level model was designed to obtain the reconstruction capacities of the branch roads. The results show that by the bi-level model and its algorithm, the optimum scheme of urban branch roads reconstruction can be gained, which reduces the saturation of arterial roads apparently, and alleviates traffic congestion. In the data analysis the arterial saturation decreases from 1.100 to 0.996, which verifies the micro-circulation transportation’s function of urban branch road network. Foundation item: Project(2006CB705507) supported by the National Basic Research and Development Program of China; Project(20060533036) supported by the Specialized Research Foundation for the Doctoral Program of Higher Education of China     

D-23.5/131-143氮氢气循环压缩机气阀改造

D-23．5／131-143氮氢气循环压缩机是四川美丰化工股份有限公司德阳分公司新建200kt／a合成氨及300kt／a尿素工程的关键设备之一。该压缩机装机试运行时，电机电流过大，严重影响整个系统的正常运行。通过分析发现，该压缩机气阀通流面积过小，为此，从气阀结构型式、气流通道等方面对该压缩机气阀进行改造。改造后的气阀装机投用后，压缩机电机电流得到较大幅度下降且具有良好的可靠性。     

上市公司文本信息披露智能分析研究综述

对上市公司发布的文本信息披露进行分析是投资者了解公司经营状况、做出投资决策的重要途径,然而人工阅读和分析的方法存在效率低、成本高等问题。人工智能技术的发展则为文本信息的智能分析提供了契机,能够从海量企业文本数据中挖掘有价值的信息,充分发挥数据驱动的优势,大幅度提高分析效率,成为近些年的研究热点。对近十年关于上市公司文本信息披露智能分析的研究工作进行了总结,分别从文本信息披露的事件类型的研究现状、智能分析方法和应用场景三个方面进行了归纳,分析了该领域当前面临的挑战,最后根据现有方法的不足指出了未来可能的研究方向。