改进的小波模极大值降噪法在DS-UWB系统中的应用

由于超宽带脉冲信号持续时间短、发射功率低,传统去噪方法已不能很好地满足系统要求,而在超宽带系统中使用小波变换技术来抑制噪声时效果比较理想．通过对小波模极大值法进行改进,提出了一种新的去噪声方法——比值门限加相似系数法,它既能有效抑制噪声,又能保留UWB信号的奇异性．仿真结果表明,与模极大值法比较,该算法更简便,去噪效果更明显.     

一款超宽带陷波天线设计

为了很好地抑制5G通信系统(3.4～3.6 GHz)(中国电信:3.4～3.5 GHz;中国联通:3.5～3.6 GHz)对超宽带(Ultra-Wideband,UWB)系统的干扰，设计了一款超宽带陷波天线，超宽带陷波天线包括带有陷波缝隙辐射片、金属地板、介质板。先设计一款可以工作在超宽带频段的天线，然后在辐射片上采用陷波技术，即开U形缝隙，使得超宽带天线在3.4～3.6 GHz频段内实现陷波特性。仿真结果表明，该超宽带陷波天线方向图和增益特性良好，能够很好地抑制5G通信信号的干扰。     

适用于多边带频分复用超宽带系统的CMOS频率综合器

采用整数分频锁相环、单边带混频器、多相位滤波器、频率选择器设计了适用于多边带频分复用超宽带系统的频率综合器.该频率综合器可以产生3.432,3.96,4.488 GHz 3个频率信号,仿真结果表明该电路提供大于35.29 dB,边带杂散抑制性能,频率信号之间的切换时间小于1.35 ns,相位噪声积分为2.62°,满足了超宽带通信系统收发机对于本地时钟性能的要求.频率综合器采用0.18μm RF CMOS工艺设计,在1.8 V电源电压下,总功耗为66.6 mW.     

超宽带抑制同步开关噪声的新型电磁带隙结构

为抑制现代高速电路中的同步开关噪声,给出了一种新型电磁带隙结构,可超宽带抑制同步开关噪声.利用软件对新型电磁带隙结构的阻带特性及信号完整性进行仿真分析.结果表明,与相同参数的Z型桥电磁带隙结构相比,当抑制深度为- 30 dB时,新型电磁带隙结构的同步开关噪声抑制带宽为130 MHz～10.45 GHz,相对带宽增加了5...     

多功能厅系统噪声的产生与抑制

多功能厅系统噪声问题常常影响整个系统扩声效果和图象质量，确保较“干净”的电源向音视频系统供电；隔绝由外界噪声产生的干扰噪声；音视频系统的信号传输和正确配接是提高线路的抗干扰能力前提；建立屏蔽系统和接地网络是抑制电磁噪声基本的有效方法。     

超宽带系统中基于时域插值和抽取的新型Sigma-Delta转换器

无线通信系统中,超宽带(UWB)与正交频分复用(OFDM)技术相结合,具有超宽带、低功耗、抗多径衰落等优势.针对多频带OFDM-UWB信号的特点,提出一种基于时域插值和抽取的新型sigma-delta转换器用于完成数据的转换.时域插值使得多频带OFDM-UWB子载波间形成空隙,sigma-delta调制器将输入信号量化为1比特数据流的同时完成量化噪声整形.该sigma-delta调制器在量化噪声频谱中引入位于多频带OFDM-UWB子载波频点上的零点,将大部分量化噪声推到子载波空隙中,达到噪声整形效果.新型sigma-delta调制器采用无过采样结构,使得硬件实现相对容易,同时该结构还避免了OFDM系统的高峰均比问题.对信号进行时域插值与抽取降低了硬件复杂度和处理时间.理论分析和仿真结果表明了该调制器的有效性和可行性.     

基于残余噪声能量的自适应杂波抑制方法

基于残余噪声能量的自适应杂波抑制方法无需对目标信号、杂波与噪声的先验统计信息做假设，权向量值由系统设定的残余噪声决定。计算机仿真结果证实了该方法可以有效地抑制杂波与噪声信号。     

基于互补序列码的超宽带搜救雷达信号处理

根据超宽带雷达目标特性建立了人体探测模型,并利用互补序列码编码的超宽带脉冲串信号对人体模型进行探测仿真.通过对比编码信号与非编码信号的探测结果和不同信噪比下互补码的探测结果,得出经互补序列码编码的超宽带雷达脉冲信号具有很好的抗噪声能力,是超宽带搜救雷达发射脉冲串的理想编码方式.     

重频参差解模糊超宽带雷达信号参数估计

针对超宽带雷达信号相关参数估计方法存在的相位模糊问题,提出基于重频参差解模糊技术的超宽带雷达信号参数估计方法,较好的解决相位模糊与参数估计精度之间的矛盾,实现了低信噪条件下对信号参数更高精度的估计。在高斯白噪声条件下对比窄带LFM信号对超宽带LFM信号进行了理论分析、仿真和比较,证明了该方法的有效性。     

群变换的BCH编码在超宽带中的误码率分析

提出了博斯-查德胡里-霍昆格母（BCH）码新的编码和解码方法,通过纠正t（t≥2）个错误,达到提高系统的抗干扰能力和克服信道衰落的影响,提高了编译码速度。在无多径加性高斯白噪声（AWGN）信道情况下,仿真并比较了不同信噪比（SNR）下BCH编码和重复编码传输PPM-TH-UWB超宽带信号和PAM-DS-UWB超宽带信号的误码率,并画出了误码率曲线。通过计算机仿真,证明在AWGN信道情况下,BCH编码在传输超宽带信号时能获得较低的误码率。     

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.     

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.     

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。     

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.