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1.
以扩展频段100kHz-13MHz电容标准作为量值传递标准,提出一种用四端对电容器标定单端口电容器相应频段频响的方法.首先,基于四端对阻抗的测量原理,分析了四端对阻抗测量中误差的产生原因;然后,借助于研制的精密四端对-单端口转换器,用四端对阻抗测量仪测量单端口电容器容量值;最后,对测量结果进行基于RBF神经网络的阻抗测量仪非线性修正和四端对阻抗测量原理的误差修正,确定单端口电容器的频率特性.经验证,该方法提高了标定结果的准确度,既实现了电容容量量值的统一,也为标定其他不同端口电容器奠定了基础.  相似文献   

2.
对电力系统中谐波的产生及其对无功补偿电容器的影响作了详细分析,阐明了抑制谐波对并联电容器危害的原理及一些有效方法.  相似文献   

3.
电力电容器用于向电力系统提供无功补偿,改善电能质量.实际运行中,电容器经常出现故障,影响电网正常运行.电容器检测系统利用串联谐振原理进行耐压试验,测量内部电容、损耗和放电量.设计了一套由组态王和PLC组成的新型检测系统,自动计算、调节电抗器和变压器,控制试验过程.  相似文献   

4.
电容器是电路的基本元件 ,在电子设备中有着广泛的运用。从电容器的特性出发 ,分析了电容器的降压和升压原理 ,介绍了电容器在小功率直流电源中的几种应用。  相似文献   

5.
(Ba0.7Sr0.3)TiO3铁电薄膜热敏电容器的研制   总被引:4,自引:0,他引:4  
采用射频磁控浅射法制备了用于非致冷红外焦平面阵列的BST((Ba0.7Sr0.3)TiO3)铁电薄膜热敏电容器,介绍了热敏电容器上下电极的选材和制备及铁电薄膜的制备工艺。根据热敏电容器的电容-温度曲线,分析了热敏电容器的工作原理。实验结果表明BST铁电薄膜热敏电容器可以工作在室温附近,约26℃处。  相似文献   

6.
超级电容器电极材料的研究进展   总被引:1,自引:0,他引:1  
超级电容器是介于传统电容器和蓄电池之间的一种新型储能装置。简述了不同电极材料的超级电容器的工作原理,综述了近年来超级电容器电极材料的研究进展以及现状,并探讨了其发展方向和研究重点。  相似文献   

7.
无功补偿的电容器最佳配置方法   总被引:1,自引:0,他引:1  
在考虑网损及电容器损耗的基础上.建立了低压配电系统模型.对电容器补偿问题进行了深入的分析.给出了一种准确实用且经济效益高的低压配电系统电容器配置新方法.通过实例验证了这种方法的正确性.  相似文献   

8.
真空浸渍设备微机控制系统黄家贤(东南大学机械工程系.南京210018)电力电容真空浸渍设备是利用真空干燥的原理,除掉电容器薄膜间的湿汽或气体,并充填绝缘油或其它介质,以达到改善电容器的介电性能,提高电容器的容量和耐压性,目前这类设备沿用传统的电气控制...  相似文献   

9.
介绍求解圆锥形电容器电容的两种方法:电容器并联法和电场能量法.通过两种方法计算得到的结果一致,最后对两种算法进行比较并指出异同点.  相似文献   

10.
本文利用微元法简洁地求出几种常见电容器的电容,同时给出椭圆柱形电容器电容的计算公式,它恰好是圆柱形电容器电容计算公式的推广.  相似文献   

11.
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.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
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。  相似文献   

14.
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  相似文献   

15.
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  相似文献   

16.
17.
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.  相似文献   

18.
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).  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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