色散和非线性效应对拉曼放大器性能的影响

从耦合振幅方程组出发,研究了色散和非线性效应对光纤拉曼放大器性能的影响。通过系统仿真,得到色散参量的变化对拉曼放大器的性能影响较大,而非线性系数对其影响较小。还仿真了采用不同光纤作为传输媒质时拉曼放大器的性能,并与传统方法的仿真进行了比较。结果表明:当仿真距离较短时,两种仿真方法的结果基本符合。但是,当仿真距离较长时,结果出现显著偏差。采用G.653光纤作为传输媒质,两种仿真方法的结果偏差较小;而采用G.652光纤,结果偏差较大。     

超长距离光孤子通信系统的性能分析

从工程应用角度，在高斯近似下建立了使用集总式放大器的超长距离光孤子通信系统的误码率公式。通过计算机模拟，对这种系统进行数值分析，为系统优化设计提供参考依据。     

光纤拉曼放大器在单芯反馈式结构中的偏振相关性研究

本文围绕光纤拉曼放大器的偏振敏感性展开研究，从已有的拉曼放大器传输理论入手，基于拉曼增益系数和偏振相关系数，引入椭圆偏振光的椭圆率角和椭圆长轴方位角评判偏振态变化量，定义了基于拉曼开关增益的偏振相关增益波动系数评判拉曼偏振相关增益，然后分析了在单向泵浦和单芯反馈式结构中应用拉曼放大器前后的输出光偏振态变化情况，得到单芯反馈式结构中的工作光输出偏振态几乎不会发生改变的推论，并设计相关实验予以证明。实验结果证实了在单芯反馈式结构中工作光的输出偏振态基本不受拉曼增益影响，且工作光增益受偏振影响显著低于单向泵浦，即单芯反馈式结构中的拉曼增益对偏振敏感性低，增益更稳定。     

WDM系统中光放大器的性能介绍

本文将介绍光放大器的基本性能,较仔细地介绍了三种光放大器,包括掺铒光纤放大器(EDFA)、半导体光放大器(SOA)、拉曼光纤放大器的基本原理和优缺点。     

2.5 Gbit/s无电感高灵敏度宽动态范围前置放大器设计

基于0.18μm RF CMOS工艺设计一种应用于无源光网络光接收机的无电感型2.5 Gbit/s前置放大器。该前置放大器主要包括跨阻放大器、单端转差分运算放大器和输出级电路。跨阻放大器基于3级推挽反相器结构,具有高增益和低噪声的特点,提高前置放大器的灵敏度;分析零点补偿原理,设计位于反馈环路之中的虚零点,提高跨阻放大器的工作速率,增加稳定性。提出一种新的具有自适应功能的自动增益控制技术,使得跨阻放大器在不同光输入功率下保持带宽不变,环路稳定,具有宽动态范围特性。研究结果表明:在误码率为10-10,传输速率为2.5 Gbit/s时,该前置放大器的接收光灵敏度高达-29 d B·m,输入最大光功率为2 d B·m,动态范围达31 d B·m;在1.8 V的电源电压下,芯片功耗为30 m W,芯片总面积为1×0.7 mm2。     

光纤拉曼放大器在提高光纤使用带宽方面的应用方法研究

全光网是宽带网的基础，是未来通讯业发展的方向，但是全光网中的光放大器一直是传输中需要解决的一个关键问题。在分析了光纤拉曼(Raman)放大器工作特点的基础上，对光纤拉曼放大器(FRA)在扩展光纤带宽方面进行了分析研究，并对几种应用方法的试验情况做了介绍。     

关于光放大器的最新发展及应用

介绍了国际上光放大器的最新发展及应用，主要包括掺饵光纤放大器、Er^3 ：Yb^3 共掺玻璃波导放大器、掺铥光纤放大器、光纤拉曼放大器及半导体光放大器，并指出相关光放大器的发展趋势．     

再生混合式放大器效率改善之设计与研究

本论文是研究一个新型Raman与EDFA混合式放大器,此放大器是利用拉曼光纤放大器(Raman Fiber Amplifier;RFA)的拉曼激发散射(Stimulated Raman Scattering;SRS)非线性特性所产生的拉曼泵激余量残光(Residual Ramanpump)再生后再导入掺铒光纤(Erbium Doped Fiber;EDF),做为掺铒光纤放大器(Erbium Doped Fiber Amplifiers;EDFA)的泵激光源,借此来提升输出功率及效能,此放大器架构并色散补偿光纤(Dispersion Compensating Fiber;DCF)应用在拉曼光纤放大器,由于色散补偿光纤不仅能改善色散损失,更能被当作拉曼光纤放大器中的增益介质;因此,利用再生混合式拉曼与掺铒光纤放大器,使整个输出增益提升18.73dB,比传统单一拉曼光纤放大器效能改善许多。本论文探讨混合式光纤放大器,可应用在长距离高密度分波多工技术(Dense Wavelength Division Multiplexing;DWDM),能作为系统设计者,在未来发展的海底光缆或长距离的光纤通信架构中,做为设计放大器...     

一种宽带光纤拉曼放大器数值模拟的新算法

以后向泵浦的宽带光纤拉曼放大器为模型,基于平均功率的思想,运用矩阵迭代法模拟信号光和泵浦光在光纤中的传输特性,数值计算出拉曼增益曲线.这种算法结合了平均功率法的快速和矩阵迭代法的简单易控制的优点,在保证计算精度的情况下能提高计算速度.理论分析结果和实验结果均显示该算法可以准确模拟拉曼放大过程.该算法可以为设计制作光纤拉曼放大器提供参考.     

一些宽带光纤放大器的原理和结构

介绍了宽带光纤放大器的两种基本类型：现已应用于工程实践的宽带拉曼光纤放大器和前景看好的超宽带光譬苎奎器。誓分析了若干具体的宽带光纤放大器的结构和性能。指出了宽带光纤放大器的研究重点是分波段光纤放大器和宽带混合光纤放大器。     

Markedness and its Interpretation in Language Use

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

Features of Women's language

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.     

A computer generator for randomly layered structures

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

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

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。     

An Index mechanism for multi-scale view in spatial databases

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

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