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1.
对于非平行平板的电容器,构造一个势函数,求电场和能量,经过对能量求极小值得到能量的近似解,进而得到电容的近似解.  相似文献   

2.
用双能量法计算椭圆柱形电容器和偏心电缆的电容   总被引:2,自引:0,他引:2       下载免费PDF全文
应用能量分析法来计算两导体间的电容.双能量法是把整个电磁装置看作一个系统,从 系统处于平衡时的能量有极大值或极小值出发.从而获得系统简单近似的能量分布.这种近似提 供了计算电容准确值的上界和下界值.  相似文献   

3.
在对偏心球形电容器的电容进行理论计算时,现有的文献大都采用在球坐标系下分离拉普拉斯方程并且假定其偏心率较小采用一阶近似得到了偏心球形电容器电容的近似解。这些计算的局限是它们只能用于小偏心率的情况,当偏心率增加时,就会带来极大的误差甚至是错误。为此本文通过在双球坐标系下分离拉普拉斯方程的方法经推导严格求解了偏心球形电容器的电容,得到了它的级数解,并通过编制程序对级数解进行计算获得了偏心球形电容器的电容大小与偏心率之间的数值关系,发现偏心球形电容器电容大小是随偏心率的增加而增加的,但是在偏心率很小的情况下电容的改变量相当小。可近似认为不发生变化,最后对这种电容器应用的前景进行了探讨。  相似文献   

4.
运用不同的方法讨论了电场中带电谐振子在坐标表象和能量表象中能量本征值和本征函数的求解方法.认为电场中带电谐振子用定态微扰的方法不仅可以求近似解,也可找到其精确解。  相似文献   

5.
采用Greene-Aldrich指数型近似方法近似表达径向方程非线性离心项,利用P-NU方法研究了含修正Yukawa-Kratzar势场的Schr?dinger方程束缚态解析解问题,得到了归一化的束缚态波函数和相应能量本征值方程,数值求解能量本征值方程并和真实值数据进行了对比。  相似文献   

6.
三维转动神经网络的研究:(1)能量函数   总被引:1,自引:1,他引:0  
简述了三维转动神经网络模型,通过对能量函数的研究,证明了网络当神经元个数远大于存贮图象数时,存贮图象为能量空间中的极小值.引入了绝热近似,有效局域场能正确迭代的几率,等于方向角和旋转角分别能正确选代的几率的乘积.  相似文献   

7.
在分析了极小值原理和直流电力拖动系统的基础上,建立了与能量损耗有关的数学模型,利用极小值原理解出了电枢电流为控制量的最优解,并对最小能量损耗控制的可行性进行了分析。  相似文献   

8.
求解了正交各向异性介质中平面椭圆夹杂在远端作用与椭圆主轴呈任意角度均匀拉力情况下受非弹性特征应变引起的弹性场.采用各向异性平面问题的复变函数解法,结合保角变换,获得夹杂内应变能和基体应变能的显式表达式.进一步,根据最小应变能原理,获得了表征夹杂,基体平衡边界的4个待定参数,从而得到了弹性应力和应变场的封闭形式的解析解.通过应力变换关系,验证了基体内边界上法向正应力和剪应力均满足连续性条件,表明了该解的正确性.  相似文献   

9.
用双能量法计算水电站中单相水电阻器的电阻把整个装置看作一个系统研究其能量从系统处于平衡时的能量有极大值和极小值出发,获得系统中简单近似的能量分布这种近似的分布提供了计算水电阻准确值的上界值和下界值计算方法简单,精确度高  相似文献   

10.
本文对加权残值法的实际应用情况进行了探讨,针对其收敛性问题提出了一种改进方法──逐次逼近法.首先利用近似解的误差分布建立误差函数,然后用最小二乘法求整体误差的极小值,问题归结为求解一个线性方程组.薄板弯曲问题算例结果表明,本方法具有计算简单、收敛速度快,能进一步逼近精确解等优点  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
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   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
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   

17.
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   

18.
19.
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   

20.
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   

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