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1.
可倾屏法是测量螺旋面牙形的一种新方法。它克服了传统光学测量方法中存在的观测对象(影象或干涉线)随调焦而变形和测量结果具有双值性的问题,从而提高了测量精度。本文阐述了可倾屏法的测量原理及主要性能。  相似文献   

2.
为了得到在[-1,1]上对非光滑函数|x|逼近误差的上界,构造了一组全新的节点集,并证明了基于该节点集的Newman型有理插值算子逼近函数|x|的误差上界为e-2/1+εn其中ε为仅依赖n的小正数,可随着n增大任意减小乃至趋于零。该误差上界优于利用Newman节点集所得到的结果。同时通过合理分配节点集在区间上的分布及改进不等式的证明方法,逼近的误差阶可进一步提高。  相似文献   

3.
本文运用达朗贝尔—欧拉定理和矢量方法分析研究了应用于天文导航的气泡式六分仪产生测量原理误差的主要因素,以及消除和减小其测量原理误差的主要设计原则和使用要求。所讨论的这些原则对应用于航海和航空的、以水准气泡作为人工水平基准的气泡式六分仪均有意义。  相似文献   

4.
探空湿度测量太阳辐射误差时空分布特征研究   总被引:3,自引:2,他引:1  
针对太阳辐射加热引起探空湿度测量产生偏干误差,采用流体动力学(CFD)软件对探空湿度测量模型施加对流-太阳辐射耦合热边界条件,模拟湿度传感器上的温度场分布,结合电容湿度传感器的工作原理和相对湿度的定义,提出了太阳辐射偏干误差修正的数值分析模型。数值分析结果表明:随着海拔高度的升高,湿度测量的太阳辐射误差随之增大;在不同的地区实施探空湿度测量,太阳辐射误差随季节变化曲线与纬度密切相关;在白天当地时间6~18点之间施放气球,太阳辐射误差随时间先增加再减小,当地时间正午12点时达到最大。为探空湿度测量太阳辐射误差修正的时空分布特征的研究提供了一种新的方法。  相似文献   

5.
从电子计数器测量周期的原理出发,分析了测周误差产生的原因并指出测周误差由量化误差、时基误差、转换误差三部分组成,在此基础上提出了减小电子计数器测周误差的几种方法;为电子计数器在频率、时间间隔等参数测量时,如何减少测量误差提供了理论依据。  相似文献   

6.
对接触线几何参数双目视觉测量原理进行分析,建立了其数学模型。应用MTALAB软件对双目测量系统结构参数和相机参数与测量误差之间的关系进行仿真分析。仿真结果表明,结构参数中两相机的光轴倾斜角α1和α2存在误差时,只要保持两者的误差正负相反,即可减小测量误差;两相机像平面中心距误差引起的测量误差较大。相机参数方面,选配焦距一致性好的两个镜头,并在计算x1和x2的过程中进行畸变补偿和减小"量化"误差,可有效减小测量误差。  相似文献   

7.
从电子计数器测量周期的原理出发,分析了测周误差产生的原因并指出测周误差由量化误差、时基误差、转换误差三部分组成,在此基础上提出了减小电子计数器测周误差的几种方法;为电子计数器在频率、时间间隔等参数测量时,如何减少测量误差提供了理论依据。  相似文献   

8.
提出了将称重传感器用于倾角测量的方法,并通过实验加以验证。实验结果及计算结果与文中理论分析基本吻合,说明用称重传感器进行倾角测量在理论上是正确的。该方法存在一定的测量误差,但误差分布规律性较强,适合应用误差补偿方法以减小实际测量误差。经过补偿,使称重传感器测量倾角的实际误差减小了约99%,达到了较高的测量精度,完全可以满足工程实际倾角测量的精度要求。  相似文献   

9.
在电化学阻抗测试中,电极作为传递信号的载体,电极与材料的接触程度,也即之间存在的接触电阻的大小,直接影响到了电化学阻抗及其阻抗谱所拟合等效电路参数的结果。通过对粉土、灰土分别在不同电极间压力和不同电极面积的正交试验下,所测得的阻抗|Z|和接触电阻R_0,来探求R_0与|Z|及其等效电路参数的关系。研究表明:电化学阻抗谱呈现非Randles模型的材料,可以提出类似于材料电阻率ρ_m的材料阻抗率ρ来表征材料的特性;同时ρ可以用其相对应的R_0与参数α的乘积表示。α随着电极间压力的增大而缓慢增大,随着电极面积的增大而急剧增大,随着材料压缩模量E_s的增大而减小;随着电极间压力的增大,其ρ、R_0、|Z|以及等效电路参数溶液电阻R_s、电荷转移电阻R_t在不断减小,而其双电层电容C_d在不断增大;随着电极面积的增大,其R_0、C_d在不断减小,而其ρ、|Z|、R_s和R_t在不断增大;随着材料E_s、ρ_m的增大,其ρ、R_0、R_s和R_t在不断增大,而其C_d不断减小。  相似文献   

10.
本文从双传声器互谱法的测量原理及测量系统的配置出发,分析讨论了互谱声强测量中的系统中的误差及其影响因素,同时给出了减小测量系统误差的可能途径。  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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