GSM网络结构调整探讨

本文从设备能力、网络容量、网络覆盖、分流、频率复用等方面分析了转型期GSM网络存在的困境,给出了网络结构调整建议,阐述LTE网络初期规划与建设时期就应借鉴GSM网络的经验,避免不必要的重复投资。     

基于可切换频率选择表面的微波加热数值研究

为解决微波加热中普遍存在的加热不均匀问题,已提出模式搅拌器、旋转转盘等机械转动方法来改变加热物体中的电场分布,从而提高加热均匀性。 然而,机械转动的方法往往使得仿真计算困难并且会增加微波系统的复杂性。 因此,本文提出一种应用于微波加热的可切换频率选择表面,其工作频率为2. 45 GHz,通过调整PIN 二极管的开关状态来改变电场分布,将不同状态下的频率选择表面在时间上进行联合并加热,可以明显提高加热均匀性和效率。 计算结果表明,该频率选择表面在导通和关闭状态下的传输系数分别为-32. 10 dB 和-0. 16 dB,能将均匀性提高 43%,加热效率提高42%,有望广泛应用于工业领域。     

Effect of Ion and Binding Site on the Conformation of Chosen Glycosaminoglycans at the Albumin Surface

Albumin is one of the major components of synovial fluid. Due to its negative surface charge, it plays an essential role in many physiological processes, including the ability to form molecular complexes. In addition, glycosaminoglycans such as hyaluronic acid and chondroitin sulfate are crucial components of synovial fluid involved in the boundary lubrication regime. This study presents the influence of Na+, Mg2+ and Ca2+ ions on human serum albumin–hyaluronan/chondroitin-6-sulfate interactions examined using molecular docking followed by molecular dynamics simulations. We analyze chosen glycosaminoglycans binding by employing a conformational entropy approach. In addition, several protein–polymer complexes have been studied to check how the binding site and presence of ions influence affinity. The presence of divalent cations contributes to the decrease of conformational entropy near carboxyl and sulfate groups. This observation can indicate the higher affinity between glycosaminoglycans and albumin. Moreover, domains IIIA and IIIB of albumin have the highest affinity as those are two domains that show a positive net charge that allows for binding with negatively charged glycosaminoglycans. Finally, in discussion, we suggest some research path to find particular features that would carry information about the dynamics of the particular type of polymers or ions.     

基于DSP的双频超声波流量计硬件电路设计

超声波流量测量技术是一种利用超声波信号在流体中传播时所载流体的流速信息来测量流体流量的新的测量技术,他具有非接触式测量、测量精度高、测量范围宽、安装维护方便等特点,特别适合用于临时管道流量、大口径管道流量以及危险性流体流量的测量。本文介绍了一种采用数字信号处理技术的双频超声波流量计的硬件电路设计方法。     

LFM-BC脉压雷达信号处理系统的仿真

运用数字信号处理理论和Matlab软件研究了具有线性调频-二相编码（LFM-BC）信号体制脉冲压缩雷达的信号处理仿真,提出了一个仿真模型,该模型能够仿真雷达信号、系统噪声与杂波和LFM-BC脉压雷达系统中信号的动态处理过程,具有很好的多普勒性能。     

β-榄香烯振动光谱的量子化学从头计算

利用G98及GAMESS从头计算程序的RHF／6－31方法,对β－榄香烯的全部振动基频作了计算,并与实测红外光谱做了对比,归属了它们的振动模式,讨论了它们的特征基频,并对理论计算的振动频率进行了标度校正。     

Inter-cell spectrum efficiency improvement technology

Improvement in inter-cell spectrum efficiency is a valuable research topic in mobile communication system, which affects cell edge user experience especially. According to current research results, there are three methods to deal with inter-cell interference to improve inter-cell spectrum efficiency, including inter-cell interference randomization, inter-cell interference cancellation and inter-cell interference coordination. This paper analyzes three important inter-cell spectrum efficiency improvement technologies, soft frequency reuse (SFR), uplink power control, and downlink coordinated multi-point transmission/reception (CoMP), and relative research progress.     

基于宽频调谐特征和谱残差分析的显著性目标检测

根据人眼视觉系统的基本特点,提出一种基于宽频调谐特征和谱残差分析的显著性目标检测算法。该方法通过在上下文信息中提取图像的宽频调谐特征,运用线性叠加融合宽频调谐特征子图得到初步特征图,然后利用多尺度方法构建多分辨率显著图谱子序列,最后利用谱残差分析融合位置特征对显著性子图进行操作运算得到最终的显著图。基于自然图像的显著性目标检测实验结果证明,该方法具有较好的实用性和较强的稳定性,能够获取较为精确的检测结果。     

基于时频分析的高频地波雷达目标检测算法

为提高海事监测中高频地波雷达(High Frequency Surface Wave Radar,HFS-WR)对运动目标的检测准确率,提出了一种基于频谱细化和小波尺度谱重排时频分析的运动目标检测算法.对HFSWR的接收信号进行频率细化处理以提高后续时频分析的频率分辨率;然后,进行基于Morlet小波的时频分析以提取目标的时频分布特征,为提高时频分布的集中性和抑制交叉项干扰,对小波尺度谱进行重排;根据得到的时频分布特征实现可疑目标区的精确检测.实验结果表明:该算法能有效检测多普勒频率相差很小的运动目标以及海杂波附近的运动目标,可用于对常规目标检测算法无法判定的可疑目标区域进行精细、准确的目标检测与分析.     

Ca2+ and cAMP regulations of microtubule sliding in hyperactivated motility of bull spermatozoa

To reach and fertilize the egg, mammalian spermatozoa change their flagellar movement in the female reproductive tract, named hyperactivation. The biochemical analyses of the hyperactivated movement using demembranated spermatozoa defined the factors inducing this peculiar movement; namely, large asymmetrical flagellar movement observed in the early stage of the hyperactivation was induced with a high Ca²⁺ concentration while large symmetrical flagellar movement in the late stage of the hyperactivation was generated with low Ca²⁺ and high cAMP concentrations. Under these conditions, the microtubule sliding of bull sperm flagella was investigated by disintegrating the sperm flagella with MgATP²⁻ after extracting their plasma membrane and mitochondria. The large asymmetrical flagellar movement was caused by a long sliding displacement of a fiber of the doublet microtubules. On the other hand, the large symmetrical flagellar movement was generated by a large amount of microtubule sliding by many doublet microtubules.