同时计算二维实序列的DFT和二维实序列的DFT的IDFT的新公式

利用二维离散傅里叶变换（DFT）的一些性质，将Gunther提出的关于同时计算一个N点实序列的DFT和另一个N点实序列的DFT的逆离散傅里叶变换（IDFT）的4个新的直接公式中的第1和第4个公式，以及他提出的关于同时计算2个N点实序列的DFT的新公式推广到了二维的情形，并给出了相关证明。这些结果在处理实信号时是非常有用的。     

利用小波包算法实现快速近似K-L变换

分析了 K-L变换的不足 ,研究了利用小波包算法实现快速近似 K-L变换的问题 ,并对两种算法的复杂度进行了比较。实验结果表明 :提出的快速近似 K-L变换算法在精度和速度两个方面都具有明显的优势。     

利用FHT法反演海洋重力

从快速 Hartley变换 (FHT)基本概念入手 ,给出了 Hotine核在平面近似、球面近似、Molodenskii近似下的反演模型。另对 FHT处理中所需的坐标转换以及边缘效应等问题加以讨论。同时 ,为了改善长波特性的重力场信息 ,利用 M阶次的参考重力场对上述 Molo-denskii模型进行了改化。     

傅立叶变换红外光谱联用技术在化石燃料分析中的应用

对傅立叶变换红外光谱联用技术在化石燃料分析中的应用进行了较全面的总结评述,重点介绍了气相色谱／红外光谱联机、高压液相色谱／红外光谱联机、薄层色谱／红外光谱联机、超临界流体色谱／红外光谱联机、裂解色谱／红外光谱联机、热重分析／红外光谱联机、气相色谱／红外光谱／质谱三机联用技术等在化石燃料的结构组分分析、成因机理研究及其勘探等诸方面的重要应用,尤其是在芳香族化合物和几何异构体的分离鉴定方面发挥出的突出功效。引用文献５９篇。     

震后经济损失及人员伤亡快速预估方法

为快速了解破坏性地震发生后建筑物破坏所造成的人员伤亡和经济损失,合理投入救灾所需人、财、物,便于领导决策和指挥,提出震后经济损失和人员伤亡快速预估方法。依据地震发生的基本参数、地震地质条件等预估灾害范围、建筑物破坏程度、经济损失、人员伤亡等情况,给出地震发生早期影响尺度的快速预测结果。     

A Single-Station Spectral Model of the Monthly Median foF2 and M(3000)F2

A new single-station model (SSM) for monthly median values of the ionospheric parameters foF2 and M(3000)F2 has been developed. Fourier analysis provides a tool for decomposing the time-varying ionospheric parameters. The 12–month smoothed sunspot number R ₁₂ was used as an external solar characteristic because of its availability and predictability. However, for the first time, the solar activity is described not only by R ₁₂ , but also by the linear coefficient K _R representing the tendency of the change of solar activity. A general non-linear approximation of the influence of the solar-cycle characteristics R ₁₂ and K _R and ionospheric parameters foF2 and M(3000)F2 was accepted. The new SSM is applied to several European stations and its statistical evaluation shows better results than the other two SSMs used in the paper. The approach described in the paper does not contradict the use of different synthetic ionospheric indices (as the T-index, MF2–index); the basic aim is to show only that using one additional new characteristic of the solar-cycle variations, such as K _R , improves the monthly median model.     

A new solution for a partially penetrating constant‐rate pumping well with a finite‐thickness skin

A mathematical model describing the constant pumping is developed for a partially penetrating well in a heterogeneous aquifer system. The Laplace‐domain solution for the model is derived by applying the Laplace transforms with respect to time and the finite Fourier cosine transforms with respect to vertical co‐ordinates. This solution is used to produce the curves of dimensionless drawdown versus dimensionless time to investigate the influences of the patch zone and well partial penetration on the drawdown distributions. The results show that the dimensionless drawdown depends on the hydraulic properties of the patch and formation zones. The effect of a partially penetrating well on the drawdown with a negative patch zone is larger than that with a positive patch zone. For a single‐zone aquifer case, neglecting the effect of a well radius will give significant error in estimating dimensionless drawdown, especially when dimensionless distance is small. The dimensionless drawdown curves for cases with and without considering the well radius approach the Hantush equation (Advances in Hydroscience. Academic Press: New York, 1964) at large time and/or large distance away from a test well. Copyright © 2007 John Wiley & Sons, Ltd.     

OFDM基带处理系统的设计与实现

阐述了适合高速无线数据传输的正交频分复用(OFDM)调制方式的基本原理及调制解调的快速傅立叶变换(FFT)实现,并给出OFDM基带处理系统的结构图和硬件模块框图。     

Shell‐shape and morphometric variability in Mytilus galloprovincialis from micro‐tidal environments: responses to different hydrodynamic drivers

Tidal conditions differently influence inter‐tidal organisms in terms of general physiological and metabolic responses. In this study we investigated the morphological response in shells of Mytilus galloprovincialis native to different micro‐tidal coastal environments in the Northern Adriatic Sea. Our purpose was to highlight the ecophenotypic variability across tidal levels and to elucidate how tidal currents and waves produced by anthropogenic activities may play a part in modulating shell morphology. Three sampling sites were selected: an open‐sea area 15 km off‐shore and two sites within the lagoon of Venice, the first near one of its three inlets, and the other one in the proximity of Venice city centre. At each sampling site, organisms were seasonally collected at different depths within their vertical zonation, either in the inter‐tidal zone – i.e. at both the highest and lowest tide zonation limits, and subtidally. The mussel shells were analysed by investigation of their morphometric relationships (height/length and width/length ratios) and by elliptic Fourier analysis of the shell contours. Shell thickness and condition index were also evaluated for a better comprehension of energy allocation/partitioning. Estimates based on long‐term measurements, visual observation, wind statistics and wave growth laws allowed an evaluation of the forces acting on shells. At the open‐sea site, the observed phenotypic variability of both shell shape and thickness was clearly related to the tidal vertical zonation. At the two lagoon sites, the currents generated by tidal flow through the inlet and the waves caused by the frequent passage of boats influenced both shell shape and thickness. A trade‐off between protection and growth was apparent along the tide gradient, as emphasized by the differences in the partitioning and allocation of energy between shell and flesh production.