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1.
对于电容耦合电路的不同实际状态 ,研究了完全由耦合引起的量子涨落减小问题 .如果耦合电路处于基态 ,或者开始时耦合电路解耦 ,那么分回路以及耦合部分的电荷量子涨落能够降低 ,而电流的量子涨落却不能 .如果初始时 ,耦合部分是断开的 ,那么分回路中电流的涨落不能被压缩 ,而耦合部分电流的涨落以及各处电荷的涨落都会得到减小  相似文献   

2.
本文讨论涨落对汤姆生型电子管振荡器的影响。所得结果表明此类自振动系统在自激阈附近的振幅涨落比远离阈值时的涨落大很多。本文中所求出的振幅涨落的表达式在远离阈值时的结果与等人所得结果一致。  相似文献   

3.
用统计学原理研究了位相涨落和振幅涨落时对激光辐射的互相干函数和频谱密度的影响,得到了热辐射情况下导出的自相干函数和强度涨落相干函数间的关系式在激光辐射情况下不再适用的结论。  相似文献   

4.
通过将热场动力学推广到含时体系,研究了有限温度下介观含时LC电路中的量子涨落.虽然温度的升高会使量子涨落增加,但电容和电感等物理量的时间变化却能使涨落减小.电源的存在会对电荷和磁通量的平均值有贡献,但不会影响量子涨落.当电路中有电源时,电荷和磁通量的平均值会依赖于温度;而当电路中没有电源时,各平均值为零,自然与温度无关.  相似文献   

5.
研究了介观电感耦合电路中压缩态的产生及涨落压缩问题,如果电路参数电容和电感随时间变化,则有源电感耦合电路的本征态是压缩平移Fock态,当电路的频率不变时,电感增加,电荷的量子涨落有压缩,而电流的量子涨落无压缩,电感减小,电流的量子涨落有压缩,电荷的量子涨落无压缩,耦合电感有助于减小电流的量子涨落,温度上升使量子涨落增加,利用电容和电感的时间演化能够降低温度引起的热噪声。  相似文献   

6.
处理涨落有系综法准热力学方法,前者往往只讨论能量及粒子数的涨落,运用后者可以方便地计算各种热力学量及其相关涨落,因而是研究涨落的重要方法,学生在学习准热力学理论时,普遍存在以下问题:(1)对涨落与系统的约束密切相关,因而每一涨落公式都有其适用条件缺乏明确认识,看到同一个热力学量的均方涨落(如(?)),或同一对热力学量的相关涨落(如(?)),有不同表达式时,感到困惑,甚至错误地认为,这是采用不同方法(系综法和准力学方法)的结果.(2)解题时不知怎样选取独立变量使计算最简便,盲、乱现象严重.针对以上问题,本文将通过例题说明涨落与系统约束的关系,及选取独立变量的原则和具体方法.  相似文献   

7.
生物的发生、发展和灭亡,总是与生物的熵变(dS)密切相关的。当dS>0时,生物解体;dS=0时,生物保持原有的稳定状态;dS<0时,则出现新的有序的耗散结构。生物的熵变所引起的涨落决定了生物演化表现为由于涨落回归而保持的长期稳定性及涨落导致的短时间内的成种作用。从生物熵的变化解释了地质记录上中间过渡类型的缺失、辐射,活化石和生物大量绝灭等现象。  相似文献   

8.
从无耗散介观LC电路体系的经典运动方程出发,研究了体系处在平移压缩Fock态时电流电压的量子涨落,结果表明:量子涨落大小只依赖于其中器件参数和压缩参量,而与平移参量无关。  相似文献   

9.
利用涨落理论确定液体均匀核化速率   总被引:1,自引:0,他引:1  
基于统计热力学涨落理论 ,按照能量涨落的概率分布规律提出了全新的计算过热液体均匀核化速率的理论 ,即系综中发生气化的系统数目取决于系综中能量涨落值达到形成稳定泡核的功量的概率 .针对吉布斯正则和巨正则系综推导了相应的计算公式 .新方法考虑了升温或降压速率对核化速率的影响 ,体现了均匀核化过程的动态特性 ,同时也表明均匀核化速率不是一种物性参数 .用所得公式对一些物质的均匀核化速率进行了计算 ,计算结果表明 ,涨落方法中核化速率随过热程度的变化较动力学方法计算结果平缓 ,在过热程度低时前者高于后者 ,在过热程度高时则相反 .同实验数据的对比证实了本文所提出的理论和公式的合理性  相似文献   

10.
在热压缩态下介观电容耦合电路中的量子涨落   总被引:1,自引:0,他引:1  
利用热场动力学(TFD)方法研究了有限温度下介观电路中的噪声或涨落压缩问题,分析了对信息交换起重要作用的电路耦合部分的情况,当电路处于热压缩态时,选取不同的参数,电荷和电流的涨落分别可以得到压缩,电容耦合对分回路以及耦合区域的电荷涨落压缩有增强效应,但是对于电流则没有这样的效果。  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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