模拟城市酸雨条件下形成铜锈的稳定性研究

设计了可以重复获得铜锈的试验方法,把形成的铜锈从基体上剥离,填充到多孔微电极中,在模拟城市强酸雨条件下(0.2 gL-1Na2SO4+0.2 gL-1Na HCO3,pH值为3的酸性溶液中),测试了铜锈的电化学行为.在硼酸溶液中,通过循环伏安法测试表明,铜锈的电化学反应存在Cu(II)/Cu(I)和Cu(I)/Cu两个还原过程;对比试验发现,在腐蚀型测试介质中(模拟城市酸雨),阳极区可以观察到氧化现象,但是由于BiTA对铜锈的稳定作用,峰值电流明显降低.明确了BiTA对铜锈溶解的抑制效果.     

如何有效利用卫星轨道和频谱资源

根据卫星轨道和频谱资源的有限性,提出了有效利用卫星轨道和频谱资源的几种方法.     

章鱼图由Laplacian谱确定

如果与图G同谱的图都与G同构,则称图G由它的谱确定.重合星图K1,q的中心点和圈图Cn的一个点得到章鱼图.证明了这一类单圈图由Laplacian谱确定.     

一种液相色谱键合相的制备及评价

本研究通过引入杯芳烃配体修饰高效液相色谱的ODS固定相，利用杯芳烃的多种超分子作用改善对极性化合物的分离，弥补ODS的不足，以期拓展其应用领域。     

Signal Extraction and Forecasting of the UK Tourism Income Time Series: A Singular Spectrum Analysis Approach

We present and apply singular spectrum analysis (SSA), a relatively new, non‐parametric and data‐driven method for signal extraction (trends, seasonal and business cycle components) and forecasting of UK tourism income. Our results show that SSA slightly outperforms SARIMA and time‐varying‐parameter state space models in terms of root mean square error, mean absolute error and mean absolute percentage error forecasting criteria. Copyright © 2011 John Wiley & Sons, Ltd.     

Construction of balanced rotation symmetric boolean functions with optimal algebraic immunity

Algebraic immunity is a new cryptographic criterion proposed against algebraic attacks. In order to resist algebraic attacks, Boolean functions used in many stream ciphers should possess high algebraic immunity. This paper presents one main result to find balanced rotation symmetric Boolean functions with maximum algebraic immunity. Through swapping the values of two orbits of rotation class of the majority function, a class of 4k＋l variable Boolean functions with maximum algebraic immu- nity is constructed. The function f（x） we construct always has terms of degree n-2 independence of what ever n is. And the nonlinearity off（x） is relatively good for large n.     

基于SVS-603传感器的波浪反演技术及海上比测数据分析

波浪反演技术是传感器研制的重要组成部分。将SVS-603传感器安装在DWR-MKIII浮标上，进行SVS-603与DWR-MKIII的实测数据对比，对SVS-603的波浪反演技术进行深入分析，同时对比时域、频域光顺算法结果的差异性和可靠性。结果表明：SVS-603的时域光顺算法结果与DWR-MKIII所得结果最为接近；使用频域光顺算法时，出现了SVS-603自身的低通滤波器没有完全将低频信号过滤掉的现象，这影响到波浪谱，进而影响谱峰周期等参数。该研究能够为基于加速度原理的波浪设备研发提供更加准确的波浪算法。     

主用户模拟攻击下的协作频谱感知方法

针对存在主用户模拟攻击(primary user emulation attack, PUEA)下的频谱感知问题,提出了一种基于攻击强度阈值(attack-aware threshold, ART)的协作频谱感知方法。该方法首先建立了存在PUEA的网络模型,然后分析4种状态下协作频谱感知的特点,采用检测统计量的一阶和二阶矩估计出PUEA攻击的概率,最后以总误差概率为目标函数,求出不同攻击强度下的最佳门限阈值,并通过ART方法完成在不同攻击强度下的协作频谱感知。仿真实验表明,该方法能够估计恶意信号出现的概率,有效减少频谱感知总误差概率,提高整个网络的频谱感知性能。     

磺化改性木素的红外光谱

硫酸盐木素经常压和加压磺化改性后，其红外光谱特征有明显改变。常压改性的木素大分子职的磺酸基因主要定位在苯环上，而加压改性的则主要在与苯环相联接的侧链上，红外光谱说明了它们之间的不同。     

Guardband Analysis for Distributed OFDMA with User Heterogeneity

This paper presents an in-depth analysis of the interference strength and required guardband width between coexistent users for distributed orthogonal frequency division multiple access (OFDMA).In dynamic spectrum access networks,the cross-band interference between spectrally adjacent users is considered harmful with frequency guardbands inserted between spectrum blocks to eliminate the interference.However,the strength of the cross-band interference depends heavily on the user heterogeneity in different OFDM configurations.The cross-band interference due to the three user heterogeneity artifacts of power heterogeneity,sampling rate heterogeneity,and symbol length heterogeneity is investigated to determine the required guardband width.Analytical and simulation results show that the greater user heterogeneity requires larger guardbands with the sampling rate heterogeneity having the greatest effect.These results can be used to assist the design of spectrum allocation strategies.