一种应用于DDS+PLL混合频率综合器中的滤波器设计

主要研究设计了PLL+DDS环外混频混合频率综合器中的带通滤波器,系统把DDS与PLL经混频器混频后,通过窄带带通滤波器滤波,得到了所需中心频率的输出信号.为了缩短设计周期,提高微带线带通滤波器的性能,通过ADS中的无源电路设计向导,设计出了一种中心频率为2.5GHz,带宽为65MHz,阻带频率在2.375GHz和2.625GHz处衰减幅度大于50dB的平行耦合微带线带通滤波器.最后经过实物测试表明,设计出的平行耦合微带线带通滤波器满足各项指标要求.     

平行耦合微带线输出带通滤波器的最优化设计

本文在相关数学模型的基础上，推导出平行耦合微带线和平行耦合微带线输出带通滤波器插损的精确表达式。并以带通滤波器插损作为目标函数，以降低损耗为目的，进行常通滤波器的最优化设计。具体实例的设计表明，在不改变原设计性能指标的基础上，经过优化处理之后的带通滤波器平行耦合对之间的缝隙ｓ／Ｈ明显减小，导致总的插损大大减小，从而改善了带通滤波器的滤波性能。     

基于阶跃阻抗谐振器的耦合微带带通滤波器设计

针对寄生通带降低了耦合微带带通滤波器选择性的问题,设计了1／4波长型阶跃阻抗谐振器（SIR）的微带带通滤波器．以平行耦合微带线为基础。从上层微带线结构着手,对SIR的谐振特性和设计参量进行了推导,根据微带带通滤波器的设计指标,在馈线端端接相应的SIR谐振结构。使带通滤波器在寄生通带处的衰减达到了．45dB,提高了带通滤波器的选择性．采用插入损耗和网络综合的方法,利用ADs仿真工具对该滤波器进行优化仿真设计。结果表明。基于SIR结构的滤波器克服了寄生通带对设计通带的影响,提高了滤波器的带外抑制能力．     

基于共面波导/微带线耦合结构的超宽带滤波器设计

针对高性能和小型化宽带滤波器设计问题,利用微带线和共面波导之间的大面积重合以及介质基板所导致的强耦合效应,设计了一款CPW/微带线结构的超宽带带通滤波器.分析了所设计带通滤波器的等效模型,讨论了耦合区域长度对滤波器性能的影响.CST软件仿真的结果表明,所设计的滤波器满足超宽带滤波器的设计指标,与其他同类滤波器相比,具有设计更简单、结构更紧凑的特点.     

微带线带通滤波器的设计

阐述了工作在中心频率为几个ＧＨｚ带通滤波器的设计过程，介绍了带通滤波器的设计的原理，利用计算机辅助设计工具ＭＡＴＬＡＢ进行数值计算，给出微带线的ＰＢＣ尺寸，并用软件包ＥＥｓｏｆ模拟出带通滤波器参数。     

新型开环谐振器带通滤波器的设计

提出一组新型的方形开环谐振器,使用这种新型的谐振器设计微带线带通滤波器,可以有效地减小滤波器的尺寸.利用其中一种新型的谐振器,设计加工了一个小型化带通滤波器,仿真与测试结果显示,该滤波器有很好的频率选择性、阻带特性和较小尺寸.与传统的开环谐振滤波器比较,尺寸减小了30%.     

微带线实现环形交叉耦合带通滤波器的设计

本文设计一种应用于小型化微波系统的微带线环形交叉耦合带通滤波器,可以更好改善系统的性能,应用较广泛.     

基于低温共烧陶瓷工艺的370GHz三阶带通滤波器设计

基于低温共烧陶瓷工艺(LTCC),设计了工作在370 GHz的三阶带通滤波器.采用有限元分析软件HFSS提取了LTCC工艺下矩形波导的复传播常数,并精确计算了LTCC工艺下矩形谐振腔的品质因数和耦合系数,用于辅助带通滤波器的设计.随后设计了能够用于进一步探针测量的微带线到矩形波导转换器.最终得到的三阶带通滤波器中心频率370 GHz,相对带宽4.7%,插入损耗0.7 d B,回波损耗22 d B,带外抑制大于28 d B.     

电压调谐带通滤波器的设计研究

研究用传输线加载电容实现电压调谐带通滤波器的问题,给出了在已知一个滤波器的设计技术指标时如何进行设计的方法.讨论了微带线梳状滤波器的设计,同时分析了在设计以及调试时所出现的一些问题及其解决方法.     

基片集成波导带通滤波器设计方法的研究

文章中利用基片集成波导和双模滤波器两种技术,对基片集成波导双模带通滤波器的设计进行了研究,设计了一种微波带通滤波器结构,该滤波器结构简单,无载品质因数高达9000.应用凹型过渡结构,使基片集成波导与微带线的过渡问题得到很好解决,使基片集成波导双模带通滤波器便于集成.设计的滤波器中心频率在5.61GHz,通过TE102和TE201两种模式耦合,形成一个传输零点,改善了滤波器的性能,通带内反射损耗S11优于24dB,3dB带宽达50MHz.     

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