一种适用于高频地波雷达的电小双频发射天线

设计了一款适用于高频地波雷达的发射天线,通过顶部加载螺旋线圈的方式实现了天线电小化,且利用参差调谐原理,同时在顶部加载两个不同长度螺旋线圈,使天线实现双频谐振。该天线电尺寸仅为0. 085λ,且兼顾双频段和高效率的优点。利用CST电磁仿真软件进行仿真设计并制作缩比模型进行验证,仿真与实测结果吻合良好。     

基于新型体积再利用技术的一种多频带手机天线设计

本文提出了一种通过开阻抗调谐槽的方法实现对移动终端天线有限体积多次利用的新型体积再利用技术.该技术在保持天线体积不变的前提下,利用开缝技术调谐等效电容、电感,使得天线在工作需要的多个频点产生谐振,实现多频带.利用这种技术,设计并加工制作了一款工作在GSM, DCS, PCS, WCDMA频段的内置手机天线并进行了测试.结果表明,该天线在其工作频带内阻抗匹配良好,辐射效率高.且该多频PIFA天线的体积只和传统双频PIFA天线的体积相当,实现了天线小型化.实验测试结果和仿真结果一致,证明了这种新型体积再利     

基于矩形槽切换的宽带平面方向图可重构天线

针对阵列天线频带窄的缺点,在参差调谐法的基础上,通过在有源单元上引入开关可控矩形槽的方法,使天线工作在两个相邻的频带,从而达到天线总体带宽的展宽。根据该类型天线单元的谐振特性,研究了开关可控矩形槽展宽频带的原理,并设计了引入矩形槽的平面方向图可重构天线。实验结果表明:该天线可以工作在频率范围为2.21～2.49GHz的频段上,-10dB下的相对带宽约为11.6%,比采用参差调谐法进一步展宽了天线带宽,实现了天线方向图的可重构。     

利用Fabry-Perot谐振腔和介质谐振天线实现约瑟夫森结阵列的自辐射

本文提出了一种利用Fabry-Perot谐振腔和介质谐振天线,同时集成偶极天线阵实现约瑟夫森结阵列自辐射的方法.在介质基片上制作集成偶极天线阵的双晶约瑟夫森结阵列,并将其嵌入到Fabry-Perot谐振腔内.将基片作为一介质谐振天线,使其与Fabry-Perot谐振腔谐振在同一频率下,从而通过高频电磁耦合机制实现结之间以及结与外部微波电路之间的耦合.文中分别进行了数值仿真和实验研究.对一个包含166个双晶约瑟夫森结的结阵列进行了液氮温度时的测试,在片外（off-chip）检测到了75.2GHz,10pW的辐射信号,与仿真结果吻合.该方法为基于约瑟夫森效应的太赫兹（THz）源提供了一种可能.     

小型化双频微带阵列天线设计

针对双频工作的无线通信系统的传输要求,提出一种小型化双频微带阵列天线,该天线由4个矩形贴片辐射单元和微带线馈电网络组成.首先设计具有双频工作特性的开槽微带贴片单元,其馈电采用偏心侧馈的方式,可通过贴片尺寸与开槽的长度对2个工作频率进行独立调节;然后设计一分四等分功率分配器,作为阵列天线的馈电网络;最后,利用该馈电网络将等间距分布在同一直线上的4个结构相同的微带贴片单元连接,构成中心馈电的四元微带阵列天线,并利用三维电磁仿真软件对该阵列天线的性能进行仿真与优化,结果表明其在2.3 GHz和2.6 GHz 2个工作频段内可满足小型化双频带覆盖的技术要求,并具有较好的增益和方向性.     

具有带阻特性的可穿戴超宽带单极子天线的研究

为降低窄带信号对超宽带的干扰,对具有带阻特性的超宽带天线进行了研究,提出了一种对WiMAX频段具有带阻特性的超宽带单极子天线.该天线采用了聚四氟乙烯玻璃纤维柔性材料作为介质基板,以铜作为辐射贴片和接地板材料,通过在天线的辐射贴片上刻蚀出开口谐振环,使得天线在3.25-3.9 GHz频段出现阻带,有效抑制了WiMAX无线通信(工作频段为3.3-3.7 GHz)窄带信号对超宽带的干扰.天线的整体尺寸为32 mm×40 mm×0.8 mm.仿真分析结果表明,天线带宽为2.7-12.3 GHz,阻带为3.25-3.9 GHz,实现了辐射方向图H面的全向特性和E面稳定性.通过建立人体组织模型,改变天线与人体的距离对天线工作特性进行对比分析,验证了可穿戴天线的可行性.     

一种用于WLAN的双短路针调谐U形槽加载的双频微带贴片天线

提出了一种在贴片上加载U形槽并应用双短路针调谐的双频微带天线.该天线应用于无线局域网IEEE802.11b和IEEE802.11a系统中.通过在贴片天线上加载U形槽产生两个谐振频率,调节两个对称的短路钉使其工作在无线局域网的频带内,增大了天线带宽.仿真实验得到该天线的两个谐振频率分别为2.4 GHz和5.2 GHz,其低频和高频的相对带宽分别为4.2%和5%,可充分满足无线局域网的要求.     

一种“风车”形单元平面反射阵列天线的设计

为了改善反射阵列单元相位特性曲线的线性度,扩大相位补偿的覆盖范围,采用了一种新型的反射阵列单元,即在传统的反射阵列单元上方加上一层介质匹配层.仿真结果表明,相比传统的设计方式,新型反射阵列单元的相位特性曲线线性度得到明显改善,相位补偿实现了0°～360°的完全覆盖.本文中固态等离子体(GaAs)代替金属工作,利用固态等离子体的可重构特性设计了一款具有动态波束扫描的平面反射阵列天线,反射主波束的方向分别达到了预期设计的15°、20°和25°,并且每个天线的副瓣和主瓣都相差了至少10 dB以上.通过动态调节固态等离子体的激励状态,即改变反射阵列单元的谐振结构,可以实现空间波束扫描.     

一种基于光子晶体的新型微带天线的设计

微带天线在通信、雷达等领域应用广泛,但传统微带天线存在尺寸较大、后向辐射严重等缺点.通过在普通微带天线的介质基板内,引入高度不同的周期性圆柱空气隙作为光子晶体,设计了一种新型微带天线,并利用HFSS 10.0软件对该天线进行仿真.仿真结果表明,光子晶体的引入提高了微带天线的辐射增益,削弱了沿基底方向的辐射,并减弱了天线的后向辐射,天线在整个工作频段内具有良好的辐射特征.     

超宽带小尺寸介质谐振器天线

研究一种工作于3.1~10.6GHz频段的超宽带叠层介质谐振器天线.将低介电常数薄介质片插入介质谐振器和金属地面之间,可有效降低介质谐振器的Q值,展宽天线带宽.在介质谐振器下部切去1个小四面体,产生1个空气缝隙,进一步展宽天线带宽并提高阻抗匹配.对空气缝隙尺寸进行优化,使各个工作模式的频带相互重叠,产生超宽带工作带宽.在天线一侧短接金属壁,减小天线总尺寸一半以上.对设计的介质谐振器天线进行仿真实验,结果表明:试验和仿真结果一致性较好;介质谐振器天线实现4∶1的带宽(相对带宽约118%),带内增益为4~8dBi.     

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.     

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     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with