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.     

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.     

平面渐变开槽天线的改进设计

采用高阻值电阻和短路销钉加载对微带线馈电渐变开槽天线进行改进,提出一种新型超宽带天线结构.利用ANSOFT HFSS高频结构仿真软件对新型天线的整体结构进行优化,在材料为FR4的介质板上设计了一副工作频段为1～40 GHz的天线模型.仿真结果表明,新型结构克服了传统天线中馈电线对阻抗带宽的限制,并使天线尺寸缩减了37....     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

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.     

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.     

Design and analysis of generic LBS application developing platform

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.