用反滤波方法压缩天线波瓣的计算机仿真

提出用信号处理方法来压缩天线波瓣，并用计算机仿真的方法进行研究。其中心思想是将天线因子视为一个滤波函戮，无线的输出等效为回波信号经该滤波器滤波（或时域卷积）的结果。采用反滤波的方法从原理上可以去除天线因子的影响，达到压缩波瓣宽度的目的。     

印度洋dipole事件的年际变化与ENSO事件的联系

通过对nino3指数和DMI序列的分析,发现两种物理现象都有4 a左右的主要周期,而且印度洋偶极子事件还存在有2 a左右的振荡周期,而厄尔尼诺事件在2 a时间尺度上周期性不明显;对nino3指数和DMI进行年际时间尺度滤波,结果表明,在年际时间尺度上,两者的相关性比未滤波时有了一定的提高;对年际滤波之后的偶极子事件和ELNINO事件的相关分析可以发现,ELNINO对于印度洋偶极子事件的影响要大于IOD对于太平洋ENSO事件,显示了两者物理现象的影响不对称。     

基准站天线罩影响分析及标定方法研究

天线罩是一种为保护天线正常工作而设置在天线外部的结构物.为避免受到外部机械损伤,保证天线的电性能以维持正常运行,许多北斗/GNSS基准站的天线都会使用天线罩进行遮盖.由于天线罩本身材质特殊,不同型号天线受其影响不同,特别是对北斗/GNSS高程解算影响差异显著.本文首先给出了天线罩对北斗/GNSS信号吸收和折射基本原理,然后针对北斗/GNSS基准站更换天线或者天线罩时对定位、特别是高程方向的影响,提出了使用偏心观测量进行重新标定的方法.基于广东省北斗地基增强系统测试结果表明该方法可以有效改正天线罩的影响,满足北斗地基增强系统基准站坐标精度的要求.     

一种基于自适应麦克风阵的智能天线实验平台

智能天线是第三代移动通信的关键技术之一,也是当前信号处理和通信领域的研究热点.在对智能天线算法进行理论分析和仿真的基础上,有必要构建一个灵活、通用的实验平台,用以验证各种智能天线算法的有效性和实用性.探讨了一种基于自适应麦克风阵的智能天线实验平台的实现方法,介绍了该系统的原理、结构和各部分的作用.     

印度洋dipole事件的年际变化与ENSO事件的联系

通过对nino3指数和DMI序列的分析，发现两种物理现象都有4a左右的主要周期，而且印度洋偶极子事件还存在有2a左右的振荡周期，而厄尔尼诺事件在2a时间尺度上周期性不明显；对nino3指数和DMI进行年际时间尺度滤波，结果表明，在年际时间尺度上，两者的相关性比未滤波时有了一定的提高；对年际滤波之后的偶极子事件和ELNINO事件的相关分析可以发现，ELNINO对于印度洋偶极子事件的影响要大于IOD对于太平洋ENSO事件，显示了两者物理现象的影响不对称。     

航空无方向性信标(NDB)天线与地网的设计原理及计算方法

在简单分析“T”形天线和地波传输特点的基础上,以行业标准中对NDB覆盖半径和覆盖区中最小场强为切入点,运用电磁波传输和天线与地网的工程公式,探索了NDB天线和地网的设计原理和计算方法.据此建立相应的数学模型.     

多天线有限反馈机会多播调度

针对现有多天线机会多播调度方案中存在的问题,提出一种半动态机会多播调度算法,将多天线有限反馈的码字选择方案与机会多播调度方案相结合,解决了现有码字选择中的NP-hard问题,提高了系统容量。另外还提出了一种降低反馈量的次优方案。仿真显示,该方案改善了现有多播调度方案的次优算法,同时在损失少量系统容量的情况下大大降低了系统反馈量。     

一种适用于多制式移动通信的双阻双频段天线

为了满足现代多制式移动通信频段的需求,设计一种可覆盖大部分移动通信频段的超宽带天线。同时为了抑制与其他通信设备的干扰,在天线馈线旁加载两个U型谐振环用来获得双阻带特性。天线总尺寸为200mm×150 mm×3 mm。通过调整U型环可以获得不同的阻带特性。设计结果表明:天线工作在750~1150MHz和1650~2450MHz。该天线成本低、易集成,同时具有全向辐射特性,适用于现代移动通信需要。     

美国研制出可接收红外辐射的袖珍天线

美国科罗拉多州博尔德的“国家标准和技术研究所”的科学家们最近研制出一种新型的小天线,能有效地俘获红外辐射。目前,无论是电视机的室内兔耳形天线,还是接收遥远天体传来的无线电信号的盘形天线,其作用都在检测长波段电磁辐射方面。新型小天线的研制成功使天线技术扩展到了超短波范围。     

5.8GHz圆极化高增益射频识别读写器天线的分析与设计

为了满足电子不停车收费系统射频识别(RFID)读写器天线的要求,设计了一款5.8GHz圆极化高增益读写器天线。天线采用同轴线馈电方式,利用方形切角使天线圆极化、使用较大反射面提高天线增益。通过仿真和优化,天线回波损耗(<-10dB)工作带宽达到620MHz(5.55~6.17GHz),轴比(<3dB)带宽达到140MHz(5.71~5.85GHz),最大增益可达8.4dB。实际测试结果表明天线在5.8GHz附近具有良好的谐振特性,能够满足ETC使用需要,具有实际应用价值。     

Preliminary study on plasma membrane fluidity of Psychrophilic Yeast Rhodotorula sp.NJ298 in low temperature

The ability of cell to modulate the fluidity of plasma membrane was crucial to the survival of microorganism at low temperature. Plasma membrane proteins, fatty acids and carotenoids profiles of Antarctic psychrophilc yeast Rhodotorula sp. NJ298 were investigated at -3 ℃, 0 ℃ and 8 ℃. The results showed that plasma membrane protein content was greater at -3 ℃ than that at 8 ℃, and a unique membrane polypeptide composition with an apparent molecular mass of 94.7 kDa was newly synthesized with SDS-PAGE analysis; GC analysis showed that the main changes of fatty acids were the percentage of unsaturated fatty acids (C18∶ 1 and C18∶ 2) and shorter chain saturated fatty acid (C10∶ 0) increased along with the decrease of the culture temperature from 8 ℃ to -3 ℃; HPLC analysis indicated that astaxanthin was the major functional carotenoids of the plasma membrane, percentage of which increased from 54.6±1.5% at 8 ℃ to 81.9±2.1% at -3 ℃. However the fluidity of plasma membrane which was determined by measuring fluorescence anisotropy was similar at -3 ℃, 0 ℃ and 8 ℃. Hence these changes in plasma membrane's characteristics were involved in the cellular cold-adaptation by which NJ298 could maintain normal plasma membrane fluidity at near-freezing temperature.     

Information for authors

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprehensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose     

JOURNAL OF OCEAN UNIVERSITY OF CHINA

<正>Copyright Submfnion of a roanusatpt inks:that the work described has not been published before(exoept In the form of an abstrW or as part of a published lecture,review,or thesis);that it is not under consideration for publication elsewhere that its publication has been approved by ail     

Information for Authors

<正>The Journal of Ocean University of China(Oceanic and Coastal Sea Research)is a comprehensive academic quarterly sponsored by the Ocean University of China,published one volume per year.This journal is devoted to the publication of the theoretical and applied research results on oceanography and marine fisheries.The fieldcovered include the physical,chemical,biological,geo-     

Hydraulics and Hydrology in Mountain Areas

<正>The 35th IAHR World Congress was held in Chengdu,China from September 8 to September 132013.The title of the conference was:"The Wise Finds Pleasure in Water:Meandering through Water Science and Engineering".During the congress,1239 papers were presented in 139sessions for oral presentations and 7 sessions for poster presentations.After the Congress,a Committee was appointed to select some of the best papers presented at the Congress for publication,after a     

Sea ice thickness measurement in spring season in Bothnian Bay using an electromagnetic induction instrument

As an important component of the cryosphere,sea ice is very sensitive to the climate change.The study of the sea ice physics needs accurate sea ice thickness.This paper presents an electromagnetic-induction(EM) technique which can be used to measure the sea ice thickness distribution efficiently,and the successful application in Bothnian Bay.Based on the electromagnetic field theory and the electrical properties of sea ice and seawater,EM technique can detect the distance between the instrument and the ice/water interface accurately,than the sea ice thickness is obtained.Contrastive analysis of the apparent conductivity data obtained by EM and the value of drill-hole at same positions allows a construction of a transformable formula of the apparent conductivity to sea ice thickness.The verification of the sea ice thickness calculated by this formula indicates that EM technique is able to get reliable sea ice thickness with average relative error of only 12%.The statistic of all ice thickness profiles shows that the level ice distribution in Bothnian Bay was 0.4-0.6 m.     

Thermohaline structure inhomogeneity associated with polynia at the northern margin of Emery Ice-shelf

Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.     

Phylogenetic analysis of cultivable bacteria isolated from Arctic sea-ice

Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter.     

Information for authors

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied