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1.
提出一简单的理论模型用以F-P腔型的多种效应光学双稳态器件的最优化设计。给出影响光学双稳态的各种参数的最优化选择的理论解析表达式,以液晶为介质按最优化设计制作的器件在实验得到低达90μW/mm^2的临界入射光强的光学双稳态,理论计算的临界光强与实验值相当一致。  相似文献   

2.
具有非线性周期结构光学介质的光学双稳性   总被引:2,自引:0,他引:2  
应用F-P腔的简单理论,首次推导出非线性周期结构光学介质的入射光强和出射光强关系的解析表达式,并用它详细讨论了此种介质的光学双稳态的产生条件,临界入射光功率以及开关点的特性.临界入射光功率可低於1μW。  相似文献   

3.
应用耦合波理论,将非线性周期结构介质的非定域问题归结为耦合系数的变化,在一定的条件下给出非定域非线性周期结构光学介质的入射光强和透射光强关系的解析表达式,并讨论了非定域非线性周期结构光学介质产生双稳态的条件,临界入射光强。  相似文献   

4.
从热传导理论、法布里-珀罗(F-P)腔和光学双稳态理论出发,推导出产生光学双稳态的临界入射光功率的公式。讨论了F-P腔反射镜R_F及R_B的最佳选择,同时也讨论了F-P腔夹层的非线性介质材料、腔长等的选择。理论上可使产生光学双稳态的临界入射功率小到几微瓦。  相似文献   

5.
BSO晶体空间光学双稳态的理论分析   总被引:1,自引:0,他引:1  
本文对基于BSO(硅酸铋)晶体的电控自聚焦效应实现空间光学双稳态进行了理论分析,在理论上给出输出光强随输入光功率变化的“S”形关系曲线.  相似文献   

6.
光学双稳态方程的定常分岔和临界慢化现象   总被引:1,自引:1,他引:0  
用新的方法研究吸收型光学双稳态方程的定常分岔问题和临界慢化现象,给出光学双稳态的存在性证明,得到定常分岔图就是熟知的S-型双稳响应曲线;分析的临界慢化现象,给出了临界慢化时间的估计。  相似文献   

7.
本文研究了一种用雪崩异质结光晶体管和半导体激光器组成的新型光学双稳器件,讨论了在稳态工作时该双稳器件的四种工作模式。当其工作在光学双稳态模式时,最小临界触发光功率小于 10uW,高态输出光功率大于 1mW,高、低态输出光功率之比大于4dB。用该双稳器件实现了与、或、非、与非、或非五种基本光学逻辑功能。  相似文献   

8.
给出了非线性周期介质中前行波和背行波的非线性耦合波方程,考虑到耦合系数与介质内的光强有关。在一定简化下得到方程的解释解并在无任何简化情况下用数值解给出不同失谐量时入射光强Ii对出射光强It的关系图。二种(简化和无简化)情况下均得到了光学双稳态。此外还讨论了产生光学双稳态的条件。  相似文献   

9.
偶氮苯饱和吸收的光学双稳态的稳态理论研究   总被引:1,自引:0,他引:1  
通过理论模拟,研究了稳态条件下,基于偶氮苯光致异构的饱和吸收效应的光学双稳态性质.首先计算了在饱和吸收条件下样品的透射率随入射光强的变化关系,然后计算在饱和吸收条件下光学双稳态过程.结果表明,在稳态条件下,基于偶氮苯的光致异构过程能够实现光学双稳态的开关过程,光学双稳态开关过程主要受以下3个因数影响:①样品的温度(用K参数表示),研究表明偶氮苯稳态条件下开关过程随K值的增大而明显增强;②反式偶氮苯分子的吸收截面σT,双稳态开关过程随σT的增加而增强;③顺式偶氮苯分子的吸收截面σC,开关过程随σC的增加而减弱.  相似文献   

10.
含有饱和吸收介质的环形激光器,其输出性质之一是产生光学双稳态,这是一级相变。本文将讨论激光谱线在多卜勒展宽情况下对单模环形激光器的光学双稳态产生的影响。从H.Haken的激光理论中的Langiven方程出发,导出输出光强满足的方程,并对激光谱线中含自发辐射和无自发辐射的情况讨论,给出双稳面积随谱线的展宽而增大的结论。  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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