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1.
本文通过三阶非线性微分方程,指出了求非线性徽分方程的一种新不变量组的方法-自变量和因变量同时变换的方法,并且指出了新不变量组的应用。本文的方法和结果是文[1]的文[2]和综合与推广。  相似文献   

2.
通过变量变换将六阶变系数线性微分方程不变量的概念引入,并得到其不变量组,然后对不变量的性质进行了讨论,给出了一些六阶变系数线性微分方程的可积类型.  相似文献   

3.
为了研究五阶变系数线性微分方程的解法,通过变量变换,引入了五阶变系数线性微分方程不变量的概念,并得到了其不变量组;进一步讨论了不变量的性质,给出了五阶变系数线性微分方程的一些可积类型.  相似文献   

4.
Bochner-Kaehler流形的共形不变量   总被引:2,自引:0,他引:2  
本文是继续作者前文的工作,找到了在关于L′反不变子流形上的共形不变量.此不变量由子流形的第二基本量及复结构系数表示,在几种特殊的情形下,此不变量有简单的表达式,本文还讨论了拟复空型的性质,并讨论了拟复空型中关于L′反不变子流形的共形不变量,此不变量在某些场合下是人们熟知的.  相似文献   

5.
程序不变量的发现是一种提高软件质量的有效方法.不变量发现工具Daikon可以发现程序中蕴含的简单不变量形式,但不包括复杂的函数型不变量.本文基于GEP-RNC算法对指数对数型不变量发现方法进行研究,通过实验证明GEP-RNC算法可以有效的发现指数对数形式的不变量,解决了基因表达式编程算法在复杂函数形式发现中稳定性不佳,精度不高的问题,扩展了Daikon不变量测试库中程序不变量的类型.  相似文献   

6.
通过对电磁场张量指标的收缩可以得到两个电磁场的不变量,本文采用类似的方法把电磁场能量动量张量进行了指标收缩,得到一个新的电磁场的不变量.通过把这个新的不变量与以前的两个不变量进行比较,发现它们之间存在的依赖关系,并由这个新的不变量进一步探讨电磁场与电磁波的不同性质.  相似文献   

7.
余代数上的不变量在理论计算机科学中占有十分重要的地位,本文借助文献[1]的思想建立弱不变量的定义,讨论了弱不变量的性质以及与不变量的关系;其次,定义标记迁移系统的弱不变量并证明这两种定义是等价的.  相似文献   

8.
提出了一种基于独立主成分分析(independent component analysis,ICA)变量分组和集成学习的软测量建模方法.该方法首先运用ICA对输入过程变量进行分组,建立多个变量组子空间.然后在各变量组子空间内提取子样本集,降低变量和变量组之间的耦合性,并基于核偏最小二乘法(KPLS)建立预测子模型.最后,采用贝叶斯方法对子模型的输出进行集成,给出最终预测结果.运用该方法对工业橡胶密炼过程的数据进行了预测,并与其它软测量方法的结果进行比较分析,实验结果表明,本文提出的方法具有更好的预测性能.   相似文献   

9.
基于核磁共振的代谢组学数据预处理   总被引:1,自引:0,他引:1  
数据归一化是预处理中的重要组成部分,本文采用正常大鼠与I型糖尿病模型大鼠的尿液核磁共振谱图作为测试数据,研究了线归一、面归一和模归一3种数据预处理方法对代谢组学数据PCA分析结果的影响.分析结果表明,面归一预处理方法能够更好地在PC得分图上将对照组和糖尿病组的样本分开.此外,为了有选择性的去除代谢组学数据组中的噪声变量,本文引入新的参数R来评估PC得分图的分类效果,并把它引入适应度函数,设计相应的遗传算法,对代谢组学数据进行变量选择.经过变量选择后,主成分得分图上不同类别样本的可分性提高了,而且变量数大大地减少,更有利于特征代谢物的标记与识别.  相似文献   

10.
子流形的共形不变量   总被引:1,自引:1,他引:1  
本文给出子流形的共形不变量的一般公式,用它可以获得子流形的所有共形不变量.  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
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   

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.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  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.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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