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1.
研究非完整力学系统的Hamilton对称性与守恒量.将非完整系统纳入广义Birkhoff系统,建立了用正则变量表示的运动微分方程,给出了系统的Hamilton对称性的定义和判据,导出了非完整力学系统的Hamilton对称性导致守恒量的条件及其形式.作为特例,文章给出了非保守力学系统和Hamilton系统的Hamilton对称性与守恒量.文末举例说明结果的应用.  相似文献   

2.
研究时间尺度上弱非完整系统的Noether对称性与守恒量.建立了时间尺度上弱非完整系统对应的一次近似系统的运动微分方程,给出时间尺度上弱非完整系统的一次近似系统的Noether对称性的定义和判据,得到一次近似系统的Noether对称性导致的近似守恒量的表达式,并举例说明其结果的应用.  相似文献   

3.
本文研究相空间中非ЧΕΤАΕВ型非完整系统的Mei对称性 ,给出相空间中非ЧΕΤАΕВ型非完整系统Mei对称性的定义和判据 ,得到Mei对称性的结构方程和守恒量形式 ,并举例说明结果的应用  相似文献   

4.
为了研究可控非完整系统的Noether对称性和守恒量,根据Hamilton作用量在时间和广义坐标的无限小变换下的不变性,给出了系统的广义Noether定理及其逆定理,得到了相应可控完整系统的Noether对称性与可控非完整系统的Noether对称性的关系,并给出了在实际中的应用。  相似文献   

5.
相空间中非ЧЕТАЕВ型非完整系统的Mei对称性   总被引:1,自引:0,他引:1  
本文研究相空间中非ЧЕТАЕВ型非完整系统的Mei对称性,给出相空间中非ЧЕТАЕВB型非完整系统Mei对称性的定义和判据,得到Mei对称性的结构方程和守恒量形式,并举例说明结果的应用.  相似文献   

6.
研究非保守力和非完整约束对Hamilton系统的Noether对称性的影响。Hamilton系统受到非保守力或非完整约束作用时,系统的Noether对称性和守恒量都会发生变化。原有的一些Noether对称性消失了,一些新的Noether对称性产生了,在一定条件下,一些Noether对称性仍保持不变。文中分别给出了系统的Noether对称性以及守恒量保持不变的条件,并举例说明结果的应用。  相似文献   

7.
研究非保守力和非完整约束对Lagrange系统的Mei对称性和守恒量的影响。Lagrange系统受到非保守力或非完整约束作用时,系统的Mei对称性和守恒量都会发生变化。原有的一些Mei对称性消失,一些新的Mei对称性产生,在一定条件下,一些Mei对称性仍保持不变。分别给出系统的Mei对称性以及守恒量保持不变的条件,并举例说明结果的应用。  相似文献   

8.
研究了时间尺度上奇异Chetaev型非完整力学系统的Lie对称性与守恒量问题.首先,建立了系统的运动微分方程.其次,基于时间尺度上微分方程在无限小变换下的不变性,给出了时间尺度上奇异Chetaev型非完整系统Lie对称性的确定方程和限制方程.最后,建立时间尺度上奇异Chetaev型非完整系统Lie对称性的结构方程,给出了Lie对称性的守恒量,并举例说明结果的应用.  相似文献   

9.
本文研究相空间中非ЧTAEB型非完整系统的Mei对称性,给出相空间中非ЧETAEB型非完整系统Mei对称性的定义和判据,得到Mei对称性的结构方程和守恒量形式,并举例说明结果的应用.  相似文献   

10.
研究了时间尺度上非Chetaev型非完整系统的Lie对称性及其守恒量。首先,给出了时间尺度上非Chetaev型非完整系统的运动微分方程;然后,基于微分方程在无限小变换下的不变性,得到了确定方程,给出了非Chetaev型非完整系统下的限制方程,进而建立了时间尺度上非Chetaev型非完整系统的Lie对称性及其守恒量;最后,举例说明其结果的应用。  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.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
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   

16.
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   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
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   

19.
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   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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