光纤倏逝波吸收传感器灵敏度模拟分析

基于光波导模式理论,结合光纤倏逝波吸收原理,分析了本征型单模光纤倏逝波的传输特性及功率传输情况,导出了光纤倏逝波吸收传感器的灵敏度公式。结合灵敏度公式分析了传感器的几何参数、溶液折射率及入射波长与灵敏度的关系,运用时域有限光束传播法（FD BMP）进行模拟。模拟结果表明,光纤传感区纤芯越长越细,外界溶液折射率越小,入射波长越短,其归一化输出功率越小,传感器灵敏度越高,这与理论计算和文献实验结果一致,为光纤倏逝波吸收传感器的研究提供了参考。     

Characterization of MmWave Full-Duplex Cloud-Radio Access Network (C-RAN) with RRH Selection for 5G and Beyond

In this paper, a millimeter-wave (mmWave) full-duplex (FD) cloud radio access network (C-RAN) for 5G and beyond systems is studied, where the central unit is equipped with multiple antennas, and the spatially distributed remote radio heads (RRHs) operate in FD mode. In particular, we analyze a relay selection method based on end-to-end signal to interference plus noise ratio (SINR) in the proposed system. Distinguishing features of mmWave communications such as Rician small scale fading, path loss, blockage and directivity are taken into account in both fronthaul (FH) and access links. In order to have a comparison basis, the performance of the RRH selection method is also investigated in half-duplex (HD) mmWave C-RAN. Initially, the expression of the end-to-end SINR in the proposed system is derived, and then the cumulative density function (CDF) of the end-to-end SINR is derived in both FD and HD RRHs. Subsequently, we derive performance expressions such as outage probability, average rate and energy efficiency for the RRH selection method in the proposed system in both HD and FD mmWave C-RAN. Finally, the effectiveness of the RRH selection method and the accuracy of the obtained results are verified via Monte Carlo simulation results, which show that the RRH selection method in the mmWave FD C-RAN improves the performance significantly.     

Determination of (fluoro)quinolones in environmental water using online preconcentration with column switching linked to large sample volumes and fluorescence detection

An analytical method based on online enrichment using coupled-column liquid chromatography with fluorescence detection has been developed to determine marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, norfloxacin, lomefloxacin, oxolinic acid, and nalidixic acid at trace levels in surface water. The sample containing the pharmaceuticals was pumped through a short C18 column in such a way that the analytes were retained on the column, whereas polar interferences, eluting at the first of the chromatogram, were discarded to waste. Then, the analytes were transferred by the chromatographic mobile phase to a second C18 analytical column, where they were separated following a conventional chromatography. The optimized approach allowed to preconcentrate 15 mL of sample volume adjusted at acid pH with phosphoric acid and modified with 5% of methanol, at a flow rate of 1.5 mL/min in 10 min. R(2) values were between 0.994 and 0.998, detection and quantitation limits ranged between 0.001 and 0.080 and between 0.002 and 0.100 μg/L, respectively, and the interday precision was below 9.8%. Recoveries in three different surface water samples, spiked at concentration levels between 0.002 and 0.500 μg/L (n = 3 for each spiking level), ranged from 82.1 to 125.8% with the relative standard deviation lower than 12%.     

Multiquadric Finite Difference (MQ-FD) Method and Its Application

The conventional finite difference (FD) schemes are based on the low order polynomial approximation in a local region. This paper shows that when the polynomial approximation is replaced by the multiquadric (MQ) function approximation in the same region, a new FD method, which is termed as MQ-FD method in this work, can be developed. The paper gives analytical formulas of the MQ-FD method and carries out a performance study for its derivative approximation and solution of Poisson equation and the incompressible Navier-Stokes equations. In addition, the effect of the shape parameter $c$ in MQ on the formulas of the MQ-FD method is analyzed. Derivative approximation in one-dimensional space and Poisson equation in two-dimensional space are taken as model problems to study the accuracy of the MQ-FD method. Furthermore, a lid-driven flow problem in a square cavity is simulated by the MQ-FD method. The obtained results indicate that this method may solve the engineering problem very accurately with a proper choice of the shape parameter $c$.     

一种新的DS/M-ary/SSMA方案及其在无人机数据链中的应用

无人机数据链抗干扰技术是国内外研究的热点课题.本文从提高无人机数据链的抗干扰及抗多径能力出发,基于M-ary扩频、直接序列扩频、跳频及正交频分复用等技术思想,提出了一种DS/M-ary/SSMA新方案,建立了发射机及接收机模型,推导了信号格式,给出了系统的处理增益,并与传统扩频体制进行了性能比较与Matlab仿真.理论分析与仿真表明,该方案与DS/FH系统相比,具有良好的误码性能、较强的抗干扰及抗多径能力.     

基于双层递归神经网络的路由优化算法

研究分组交换网的路由选择及流量分配问题,以网络的平均时延为优化目标函数。为使问题的解能实时、可靠地完成,将一种用于最短路径计算的双层递归神经网络应用于路由选择的流量导数法中。仿真结果表明,该算法在收敛的可靠性和计算的实时性方面有所提高。     

干涉型光纤传感器及阵列的分集检测消偏振衰落技术的研究

对干涉型光纤传感器的分集检测消偏振衰落技术进行了新的理论分析，提出了将各种信号平方后相加的信号处理方式，使之能实现单元及阵列的实时消偏振衰落信号检测。计算了这一信号处理方式可能引起的幅度最大波动，并得出三路检测偏是分集检测的一个合适取值的结论。根据理论分析，在马赫－陈德尔干涉仪上进行实验研究取得了较好结果，并设计了用于阵列的分集检测实现方式。     

System‐Level Performance of Limited Feedback Schemes for Massive MIMO

To implement high‐order multiuser multiple input and multiple output (MU‐MIMO) for massive MIMO systems, there must be a feedback scheme that can warrant its performance with a limited signaling overhead. The interference‐to‐noise ratio can be a basis for a novel form of Codebook (CB)‐based MU‐MIMO feedback scheme. The objective of this paper is to verify such a scheme's performance under a practical system configuration with a 3D channel model in various radio environments. We evaluate the performance of various CB‐based feedback schemes with different types of overhead reduction approaches, providing an experimental ground with which to optimize a CB‐based MU‐MIMO feedback scheme while identifying the design constraints for a massive MIMO system.     

Comprehensive fluorogenic derivatization–liquid chromatography/tandem mass spectrometry proteomic analysis of colorectal cancer cell to identify biomarker candidate

Existing colorectal cancer biomarkers are insufficient for providing a quick and accurate diagnosis, which is critical for a good prognosis. More appropriate biomarkers are thus needed. To identify new colorectal cancer biomarker candidates, we conducted a comprehensive differential proteomic analysis of six cancer cell lines and a normal cell line, utilizing a fluorogenic derivatization–liquid chromatography–tandem mass spectrometry (FD‐LC‐MS/MS) approach. Two sets of intracellular biomarker candidates were identified: one for colorectal cancer, and the other for metastatic colorectal cancer. Our results suggest that cooperative expression of FABP5 and cyclophilin A might be linked to Her2 signaling. Upregulation of LDHB and downregulation of GAPDH suggest the existence of a specific nonglycolytic energy production pathway in metastatic colorectal cancer cells. Downregulation of 14‐3‐3ζ/δ, cystatin‐B, Ran and thioredoxin could be a result of their secretion, which then stimulates metastasis via activity in the sera and ascitic fluids. We propose a possible flow scheme to describe the dynamics of protein expression in colorectal cancer cells leading to tumor progression and metastasis via cell proliferation, angiogenesis, disorganization of actin filaments and epithelial–mesenchymal transition. Our results suggest that colorectal tumor progression may be regulated by signaling mediated by Her2, hypoxia, and TGFβ. Copyright © 2012 John Wiley & Sons, Ltd.