光纤传感应力检测的相似模拟实验

为定量化研究矿山相似材料模型的岩层移动规律,采用光纤Bragg光栅传感器、百分表和光学全站仪等多种测量手段,建立了基于光纤Bragg光栅传感器的模型应力应变检测系统,模拟采场上覆岩层由于采动引起的移动变形过程。实验室搭建3 m×1.15 m×0.2 m的采场上覆岩层移动的相似材料模型,几何相似比1∶200,模型中埋入3个不锈钢封装和6个醋酸乙烯封装光纤Bragg光栅传感器,1个陶瓷封装的温度光纤光栅传感器用以温度补偿,模型共架设14个百分表和6条全站仪测线。实验结果表明,光纤传感器对模型开挖过程中的应力状态变化形成了监测,光纤传感器的波长漂移量与相应岩层的垮落形态密切相关;模型实际岩层运移影响了光纤传感器波长漂移量曲线的变化,在岩块断裂时引起的FBG04的最大波长漂移量为1 504.24 pm;实验所用的不锈钢封装传感器的平均灵敏度为32.53 pm/mm,醋酸乙烯封装传感器的平均灵敏度为56.32 pm/mm,醋酸乙烯封装的光纤Bragg光栅传感器平均灵敏度是不锈钢封装的1.73倍。     

光纤Bragg光栅传感技术用于应变模态检测

介绍了光纤Bragg光栅传感技术原理，阐述了基于光纤Bragg光栅传感技术和应变模态理论的损伤自诊断智能结构系统的原理，并进行了相关的实验研究。实验表明光纤Bragg光栅传感器抗干扰能力强，具有高灵敏度和长期稳定性，其作为应变测量的工具用于应变模态，进行结构损伤识别是可行的。     

光纤光栅传感器的现状与发展

概述了近几年国内外在光纤传感器领域的研究热点－光纤Bragg光栅传感器的发展与现状,这种迅速发展的功能光纤传感元件具有其它种类的光纤传感器无可拟的优点,给出了光纤Bragg光栅的基本光学特性,光纤光栅的制作技术,光纤光栅传感器的工作原理,对温度和应变的灵敏度分析以及波长位移信号的解调技术等,最后描述了其前景和主要研究方向。     

光纤Bragg光栅在分离式Hopkinson压杆实验中的应用

光纤Bragg光栅用于高频应变的测试是一个重要研究课题．文中介绍了其高频解调原理,探讨了光纤光栅传感器用于分离式霍布金逊压杆(SHPB)实验装置中应变测试的相关问题；推导了弹性杆中传播的应力波σ与传感光纤光栅中光波相位的变化量Δ(?)之间的关系式,进而建立了含有光纤光栅传感变化量的弹性杆应力波计算公式；构建了基于光纤Bragg光栅的动态应变测试系统,对中心波长分别为1550nm和1545nm的裸光纤光栅传感器以及应变片,两种传感器粘贴在被撞击弹性杆(输入杆)表面测试应变的情形进行了比较研究,给出了实验结果．研究表明,光纤Bragg光栅在高频动态应变测量中具有很好的应用潜力和前景,测试方法和结论对于光纤Bragg光栅在高频动态应变的实际测试中具有积极意义．     

基于光纤传感的玻璃封接预应力测量

为实现对玻璃中预应力的测量,该文提出了一种基于光纤传感的玻璃封接预应力测量方法。将光纤Bragg光栅传感器植入封接玻璃预留孔中,加热使玻璃熔融,再冷却固化从而使光纤传感器、玻璃、金属同时烧结在一起。通过光纤传感信号的实时监测,实现了对封接温度的实时测量。通过光纤传感信号的变化,计算出了封接玻璃中测量路径的轴向压缩应变,结合有限元分析得到玻璃中的全局应力分布。实验结果表明:光纤传感器可实现对封接过程温度和应力的监测,以玻璃中预应力为指标可以实现对封接工艺的优化。     

光纤Bragg光栅应力增敏研究

应力增敏的研究是光纤Bragg光栅传感的重要课题之一.提出了光纤Bragg光栅应力增敏的模型,推导了该模型的等效弹性模量计算公式,得到了应力与中心波长相对偏移量的关系和应力灵敏度系数表达式,表明通过适当选择弹性体的弹性模量和尺寸,就可以提高应力灵敏度系数.用弹性聚合物封装的光纤光栅理论和实验应力灵敏度系数分别是6.64×10-10Pa-1和6.14×10-10Pa-1,各为裸光纤光栅轴向应力灵敏度的57.8和54.8倍.应力灵敏度系数的理论值和实验值吻合很好.     

光纤Bragg光栅传感技术在桥梁预应力监测中的应用研究

针对桥梁预应力检测的问题,提出了采用光纤Bragg光栅(FBG)传感技术进行监测的新方案,分析了光纤Bragg光栅传感器的传感原理,进行了室内、工程现场与常规的电测技术的对比试验.结果表明:光纤Bragg光栅传感器比电检测系统传感器具有更高精度,能绝对数值测量,抗干扰能力强,结构简单,长期稳定性高,实现对工程结构的实时、在线监测.该技术在土木工程界具有广泛的应用前景.     

基于FBG的磁场传感器实验设计方案

光纤Bragg光栅(FBG)传感技术较其它光纤传感技术有其独特的优点，使其更具有研究的价值。基于光纤Bragg光栅的应变敏感性和磁性材料的磁致伸缩效应，提出了将光纤Bragg光栅应用于磁场传感测量的方案。设计方案中将光纤Bragg光栅与磁致伸缩材料相结合。实现了光纤Bragg光栅波长漂移量与侧向位移的线性调谐关系；通过测量光纤Bragg光栅波长漂移量，可以估算出外界磁场的强度变化。     

光纤光栅封装耦合对应变传感增敏的实验研究

目的 研究光纤Bragg光栅与基底材料封装耦合对应变传感的增敏问题。方法 选用弹性模量小、耐180℃度高温且对温度敏感极小的有机聚合物材料,对裸光纤光栅进行封装,封装中采用特殊的偶连工艺,实现了封装材料与光纤光栅的牢固耦合并对两种外型尺寸的封装进行了研究对比。结果 封装后的光纤光栅对应变传感有增敏作用,FS光纤光栅取得了较高的应力灵敏度,与裸光纤光栅报道值比较增敏1174倍。结论 封装后的光纤光栅应力响应曲线具有良好的线性。通过对封装结构及尺寸优化,可以实现量程与灵敏度的最优组合。     

光纤Bragg光栅锚杆应力应变监测系统

锚杆是矿山巷道的主要支护形式之一，现有锚杆支护质量检测方法无法进行远程监控、不能实现全过程监测，本文提出了采用光纤Bragg光栅传感技术进行锚杆支护质量监测的新方法。介绍了光纤Bragg光栅监测系统的工作原理及其构成，实验系统由3个Bragg光栅组成阵列，将其粘贴在长度0．6m的金属锚杆杆体表面，进行锚杆受力的检测以及与电测技术的实验室对比试验。结果表明，光纤Bragg光栅传感器具有高的测量精度，结构简单，可以实现在线实时监测。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.