Color and fluorescence of polytetrafluoroethylene treated by γ-irradiation near the melting point

Spectral characteristics of absorption and fluorescence of the optical centers formed in PTFE during gamma-irradiation near its melting temperature have been established. It was determined, that the different optical centers are responsible for the fluorescence and coloration of the irradiated PTFE. The fluorescent structures are formed both at a near-surface layer and in the bulk of the samples. Their concentration slightly changes at the various dosage of gamma-radiation (which ranged from 0.2 to 1.0 MGy), while it decreases notably with deepening into a sample. It was confirmed, that the molecular oxygen traces in a sample play a key role in the formation of the optical emission centers.     

三维高分辨地震数据处理方法

三维高分辨处理就是要拓宽有效信号的频带，并使地震数据在宽频带内有较高的信噪比。基于这一观点，进行了大量的分析、试验，设计了一套以叠前反褶积组合、大值干扰自动压制、高精度速度分析、地表一致性处理、三维DMO及叠后方向约束去噪、F－X域地震道内插、三维一步法偏移等处理方法为主的三维高分辨地震资料处理框架。通过实际资料处理表明，三维高分辨处理后的剖面比常规处理的剖面主频提高1倍以上，并且断层归位准确，信噪比较高。     

Variances, covariances and artifacts in image deconvolution

In this paper we investigate the role of estimator variance and covariance in signal and image deconvolution, where artificial structures and large fluctuations are frequently observed. The deconvolution procedure adopted in this paper is based on the Least Squares Method and the regularization, on a minimum variance property. The whole covariance matrices were taken into account in every step of the deconvolution and regularization procedures. We show that the covariances created by the deconvolution procedure are at the origin of the observed artifacts in the recovered signal.     

Command-induced vibration analysis using input shaping principles

Input shaping is a well-established technique used for reducing the vibratory response of dynamic systems. Analytical tools are available for systems utilizing input shaping. These tools aid in performance analysis by providing intuitive and computationally simple methods for determining key system attributes, such as the residual vibration in response to a command. This paper describes methods whereby arbitrary reference commands may be interpreted as input-shaped commands. This capability allows input shaping analysis tools to be used on systems without input shapers. Experimental results obtained from an industrial 10-ton bridge crane validate the theoretical developments.     

Wavelet-based inverse halftoning for error diffused halftones

This paper describes a technique for inverse halftoning based on the wavelet domain deconvolution that comprises Fourier-domain followed by wavelet-domain noise suppression, in order to benefit from the advantages of each of them. The proposed algorithm can be formulated as a linear deconvolution problem. In fact, we model such a gray-scale image to be the result of a convolution of the original image with a point spread function (PSF) and a colored noise. Our method performs inverse halftoning by first inverting the model specified convolution operator and then attenuating the residual noise using scalar wavelet-domain shrinkage. Using simulations, we verify that the proposed method is competitive with state-of-the-art inverse halftoning techniques in the mean-square-sense and that has also good visual performance. We illustrate the results with simulations on some examples.     

分形反褶积方法研究及应用

分形反褶积技术是把标度地质学的概念引入到地震信号处理之中，在标度和分形领域里结合自组织理论，用数学表达式论证了地质学与地震学的统一，使地震信号反褶积赋于实际的地质约束。     

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为有效地提高地震资料的分辨率，提出了一种新的混合相位地震子波提取方法。相同振幅谱、不同相位谱的地震子波分别对应不同的最大和最小相位分量。在复赛谱域，遵照一定的规则，子波振幅谱可以分割为两部分，其分别对应于子波的最大和最小相位分量，分割比例的不同决定了子波不同的相位，由此可以得到最大相位子波、最小相位子波、零相位子波和一系列混合相位子波。根据地震记录信噪比谱的情况，设定地震记录的希望输出子波，对地震记录进行确定性子波反褶积。依据反褶积后地震记录方差模大小和分辨率情况，最终从一系列相同振幅谱不同相位谱子谱集合中确定理想的混合相位子波，通过确定性子波反褶积达到提高地震记录分辨率的目标。对理论合成地震记录和实际地震记录进行了子波提取实验，并利用提取的地震子波对地震资料进行了提高分辨率的处理，实验结果表明了该方法的正确性和有效性。     

Wavelet analysis based deconvolution to improve the resolution of scanning acoustic microscope images for the inspection of thin die layer in semiconductor

Scanning acoustic microscopy (SAM) is used as an important non-destructive test tool in semiconductor reliability evaluation and failure analysis. However, inspection of thin die layer has proven difficult as the reflected signals from the die top and bottom are superimposed. Conventional deconvolution techniques have been used for the improvement of time resolution in A-scan signal, however, they are not effective for SAM signal because the waveform of the reflected echo is quite different from the incident waveform due to the frequency dependent attenuation and the focal effect. In this paper, in order to overcome this difficulty, a new signal processing method, wavelet analysis based deconvolution technique is proposed. Its validity is approved by computer simulations and practical performances are demonstrated by experiments for the fabricated semiconductor sample.     

用频域法确定反卷积的最佳滤波参数

本文介绍了一种确定反卷积的最佳滤波参数的新方法。该方法的特点是，只需在频域就能确定滤波参数，因而节省了大量计算时间。     

测量误差对反卷积影响的分析及其滤波器的设计思想

本文分析了测量误差对反卷积稳定解影响的机理，并以此为根据提出了关于反卷积滤波器的设计思想，其设计公式与已广泛应用的设计公式相当一致。