Measurement of ice movement in water using electrical capacitance tomography

The permafrost with the highest altitude and largest area in the mid and low latitude is located in the Qinghai-Tibet Plateau. As most frozen soils contain ice particles which are very sensitive to temperature and other external parameters, thus influencing the stability of the embankment in permafrost regions, it is very important to develop techniques to prevent damages to railway embankments due to thaw settlement. In this paper, the electrical capacitance sensors are designed to study the freezing front movement in a vessel and ice movement in water, which is the first step to apply the ECT system to the study of frozen soil. Two sensor arrangements are put into use. First, the traditional closed electrode sensors are put into use. In this arrangement, the electrodes are attached to the outside of the pipe or vessel, and the cross-sectional distribution of ice and water could be reconstructed from the capacitances measured. Also, the ice moving track at the cross section could be reflected thoroughly. Since the traditional closed electrode sensors can not meet the needs of measuring the ice freezing front movement, a new electrode sensors structure, that is, the unclosed electrode sensors are designed to satisfy the specific test of frozen soil. In this arrangement, several pairs of electrodes are arranged along the height of the vessel. A sudden decrease in the measured capacitance is observed when the freezing front advances past the electrodes. Therefore, according to the capacitance variation, the ice movement can be reflected. In summary, electrical capacitance tomography has the advantages of being non-intrusive. With different electrode sensor arrangement, ice movement and ice freezing front can be obtained. The electrical capacitance sensor system can be applied to investigate the complicated phenomena in frozen soil.     

UTM:网关安全的终极解决方案

防火墙、入侵检测、防病毒俗称网络安全"老三样",长期以来一直作为标准安全产品,在实现网络安全从无到有的过程中发挥了重要作用.但是,随着技术不断进步,用户对于网络安全的投入产出比要求越来越高,希望在构建、部署和维护网络安全系统的过程中能尽量少花钱多办事,能一步到位解决常见的安全威胁.如何真正满足用户的这些需求,是摆在信息安全厂商面前的一个难题.尽管各个厂家前仆后继,技术路线层出不穷,但鲜有成功者.     

二次冶金——钢包精炼

最初使用二次冶金工艺是为了满足不断增长的特种钢质量需求，目前二次冶金已广泛用来生产所有钢类，因为它有高的经济效益──提高生产率，作业的机动性和低的生产成本。     

半监督在线增量自学习异常检测方法研究

在深入分析现有基于监督学习和非监督学习方法的缺点后,提出了一个新颖的基于K-means与Markov模型相结合的半监督异常检测方法.半监督方法的学习样本包括已标示类别的样本和未标示样本,并且通过对已标示样本的学习来指导对未标示样本的学习来提高识别率.方法首先将经过标示的(正常的)系统调用序列投影到高维空间进行有监督聚类后,利用Markov模型来学习聚类间的时序关系,建立起正常行为的初始模型.由Markov模型产生的状态序列计算状态概率,根据状态序列概率来评价进程行为的异常情况.正常行为模型由2种关系确定:①空间分布关系(聚类);②空间的时序关系(Markov模型).在初始模型的导引下对未标示的序列进行学习,利用迭代过程对模型进行改进.实验表明,该算法能够在已标示样本较少的情况下通过对未标示样本的学习来改善模型的检测性能,达到在线增量学习的目的.     

3000m车装钻机多轴降距分动箱的结构设计

设计的用于 30 0 0m车装钻机的多轴降距分动箱 ,采用五轴平行排列的齿轮传动结构形式。第一轴、第二轴与第三轴在同一平面内平行排列 ,第三轴、第四轴与第五轴在另一平面内平行排列 ,两平面形成一定的二面角 ,既保证了降距的要求 ,又保证了输出轴线相对于输入轴线的水平偏移。分动箱空跑合试验及在 30 0 0m车装钻机上经 5 0 0 0km多种路面测试 ,证明箱体的噪音、温升均符合设计要求 ,整机运转良好     

喇嘛甸油田电网无功优化补偿技术研究

针对喇嘛甸油田电网的地点，采用了集中、分组和就地相结合的电容补偿方式，并以最优化数学理论为基础，通过分析较有影响的时变因素和分散式电网的拓扑结构，建立了无功优化补偿的数学模型，应用了一种新的算法，同时基于结构化思想编写了软件，因而为油田供配电网的无功配置提供了科学依据。实施结果表明，喇嘛甸油田６ｋＶ电网的综合网损率已由４．０％降至３．６７％。     

基于线性回归的我国房地产价格影响因素分析

自2000 年以来,为维持我国经济高速增长,房地产改革拉开帷幕。在此大背景下我国房价上涨幅度逐渐增大,为研究房价上涨的影响因素,选取国家统计局2000-2015 年间相关数据,采用计量经济学的研究分析方法,运用最小二乘法、WD 检验、BG 检验、WHITE 检验、ARCH 检验等计量方法,对国内生产总值,居民消费价格指数,年末总人口,房地产开发企业竣工房屋造价,房地产开发企业土地购置费用,房地产开发企业竣工房屋面积六个变量因素对住宅商品房平均销售价格的影响程度进行了研究分析。经过逐步分析法得出,房价的影响因素主要跟国内生产总值和年末总人口之间存在显著的线性关系。就此结论进行分析并给出了一些建议。     

The TiO<Subscript>2</Subscript> Hierarchical Structure with Nanosheet Spheres for Improved Photoelectric Performance in Dye-Sensitized Solar Cells

A bi-layer photoanode is successfully fabricated for dye-sensitized solar cells (DSSCs) composed of P25/TiO₂ nanorod (P25/TNR) as the underlayer and TiO₂ nanosheet spheres (TNSs) as the light-scattering layer. Notably, the P25-TNR provides multiple functions, including more dye loading, more efficient charge transport and a lower electron recombination rate for the photoanode. Besides, the unique structure of TNS can significantly improve the light-harvesting capacity, boosting the light-harvesting efficiency. Therefore, an enhanced short-circuit current and power conversion efficiency of 18.04 mA cm^?2 and 5.99%, respectively, were achieved for the P25/TNR-TNS-based DSSC, which was better than that of the P25-TNS-based (15.17 mA cm^?2, 5.36%) and bare TNS-based (11.43 mA cm^?2, 4.14%) DSSCs. This indicates that this bi-layer structure effectively combines the advantages of the one-dimensional (1D) nanostructure and three-dimensional (3D) hierarchical structure. In short, this work demonstrates the possibility of fabricating desirable photoanodes for high-performance DSSCs by rational design of nanostructures and effective combination of multi-functional components.