谱线分离技术的理论基础和实验研究

对能谱分析中光电子能谱重叠的原因做了深入地分析,得出了影响光谱质量在于仪器采样率低等原因,在此基础上重点给出了谱峰分离技术的理论依据──卷积法。利用仪器线型函数去卷积和高斯拟合,计算的结果与实验测量结果的对比表明,卷积法在谱线分离技术中的应用是比较成功的,它能使畸变光谱更接近实际光谱,使计算出的物理量更接近实际值,结果更精确。     

基于结构字典学习的图像复原方法

本文提出一种新的结构字典学习方法,并利用它进行图像复原。首先给出结构字典学习的基本内容和方法,然后将傅里叶正则化方法和结构字典学习方法有效整合到图像复原算法中。结构字典学习方法是先将原图像进行结构分解,再分别学习出每个结构图像中的字典,最后利用这些字典对原图像进行稀疏的表示。结合傅里叶正则化,提出了一种有效的迭代图像复原算法:第一步在傅里叶域利用正则化反卷积方法得到图像的初步估计;第二步采用结构字典学习的方法对遗留的噪声进行去噪处理。实验结果表明,提出的方法在改进信噪比和视觉质量上都要优于6种先进的图像复原方法,改进的信噪比平均提升0.5 d B以上。     

Be and P NMR analyses on Be complexation with cyclo-tri-μ-imidotriphosphate anions in aqueous solution

Microscopic information on the complexation of Be²⁺ with cyclo-tri-μ-imidotriphosphate anions in aqueous solution has been gained by both ⁹Be and ³¹P NMR techniques at −2.3 °C. Separate NMR signals corresponding to free and complexed species have been observed in both spectra. Based on an empirical additivity rule, i.e., proportionality observed between the ⁹Be NMR chemical shift values and the number of coordinating atoms of ligand molecules, the ⁹Be NMR spectra have been deconvoluted. By precise equilibrium analyses, the formation of [BeX(H₂O)₃]⁺ and [BeX₂(H₂O)₂]⁰ (X = non-bridging oxygen donor as a coordination atom in the phosphate groups) has been verified, and the formation of complexes coordinating with the nitrogen atoms of the cyclic framework in the ligand molecule has been excluded. Instead, the formation of one-to-one (ML) complexes, one-to-two (ML₂), together with two-to-one (M₂L) complexes (L = cP₃O₆(NH)₃) has been disclosed, the stability constants of which have been evaluated as log K_ML = 3.87 ± 0.03 (mol dm⁻³)⁻¹, log K_ML2 = 2.43 ± 0.03 (mol dm⁻³)⁻² and log K_M2L = 1.30 ± 0.02 (mol dm⁻³)⁻², respectively. ³¹P NMR spectra measured concurrently have verified the formation of the complexes estimated by the ⁹Be NMR measurement. Intrinsic ³¹P NMR chemical shift values of the phosphorus atoms belonging to ligand molecules complexed with Be²⁺, together with the ³¹P-³¹P spin-spin coupling constants have been determined.     

最近邻域与无邻域算法结合空间滤波实现显微光切片

运用最近邻域与无邻域算法,并结合空间滤波方法,可去除显微切层图像的离焦模糊成份,可获得高成像速度、高质量的显微光切片。对各种显微图像进行了光切片处理,并与由现有去卷积处理、结构光照明等方法获得的光切片图像进行了对比,验证了该算法在去除模糊信息方面有更好的效果,提高了图像处理效率,获得了令人满意的光切片图像。在此基础上研制出了显微光切片图像处理系统。运用最近邻与无最近邻算法,结合空间滤波方法,采用简便可调的卷积模糊算子代替点扩散函数的估计过程,图像处理方便快捷,可较好地去除离焦平面的模糊信息。     

Large eddy simulation of orientation and rotation of ellipsoidal particles in isotropic turbulent flows

The rotational motion and orientational distribution of ellipsoidal particles in turbulent flows are of significance in environmental and engineering applications. Whereas the translational motion of an ellipsoidal particle is controlled by the turbulent motions at large scales, its rotational motion is determined by the fluid velocity gradient tensor at small scales, which raises a challenge when predicting the rotational dispersion of ellipsoidal particles using large eddy simulation (LES) method due to the lack of subgrid scale (SGS) fluid motions. We report the effects of the SGS fluid motions on the orientational and rotational statistics, such as the alignment between the long axis of ellipsoidal particles and the vorticity, the mean rotational energy at various aspect ratios against those obtained with direct numerical simulation (DNS) and filtered DNS. The performances of a stochastic differential equation (SDE) model for the SGS velocity gradient seen by the particles and the approximate deconvolution method (ADM) for LES are investigated. It is found that the missing SGS fluid motions in LES flow fields have significant effects on the rotational statistics of ellipsoidal particles. Alignment between the particles and the vorticity is weakened; and the rotational energy of the particles is reduced in LES. The SGS-SDE model leads to a large error in predicting the alignment between the particles and the vorticity and over-predicts the rotational energy of rod-like particles. The ADM significantly improves the rotational energy prediction of particles in LES.     

Metamictization in zircon. Part I: Raman investigation following a Rietveld approach: Profile line deconvolution technique.

The line profile form of Raman spectra can be analyzed using the very same approach and software used for diffractogram deconvolution via the Rietveld approach. In both cases the ‘true’ profile containing information about the sample must be separated from the instrument's profile function (and potentially from the emission profile) which can be achieved by deconvolution. In this first part of a two‐part study we demonstrate how the instrument's function can be described via a Gaussian function profile (yielding the very same result as several convoluted hat functions) using several examples (diamond, calcite, silicon and silicon carbide) for which true Raman bandwidth values are presented (assuming the true band profile to be Lorentzian). Also, asymmetrical bands can be described and analyzed via the presented deconvolution approach. The second part of this study will discuss and apply this method for studying the radiation‐induced damage in zircon grains (metamictization). Copyright © 2008 John Wiley & Sons, Ltd.     

结合虚拟单像素成像解卷积的双边照明光片荧光显微技术

光片荧光显微术(light-sheet fluorescence microscopy,LSFM)采用薄片光束从侧面激发样品,在垂直于光片方向上进行成像,具有成像速度快、光学层析能力强以及光漂白和光毒性低等优点,适用于对较大活体生物样品进行高质量、长时间三维动态观测.然而,传统高斯光束LSFM存在分辨率低和成像视场小的...     

层状粘接结构超声检测信号的同态解卷积脱粘界面定征

本文利用建立的多层粘接结构超声无损检测信号的卷积模型,推导出了检测信号的解析表达式,并用同态滤波解卷积方法有效地提取出粘接结构的系统响应,进而由其中界面多次反射响应的位置、幅度和包络等特征参数,实现了脱粘二界面（指空气脱粘）的定征和识别。仿真和实验数据的处理结果表明本文方法对脱粘检测的应用有积极的意义。     

Introducing Alternative Algorithms for the Determination of the Distribution of Relaxation Times

Impedance spectroscopy is a powerful characterization method to evaluate the performance of electrochemical systems. However, overlapping signals in the resulting impedance spectra oftentimes cause misinterpretation of the data. The distribution of relaxation times (DRT) method overcomes this problem by transferring the impedance data from the frequency domain into the time domain, which yields DRT spectra with an increased resolution. Unfortunately, the determination of the DRT is an ill-posed problem, and appropriate mathematical regularizations become inevitable to find suitable solutions. The Tikhonov algorithm is a widespread method for computing DRT data, but it leads to unlikely spectra due to necessary boundaries. Therefore, we introduce the application of three alternative algorithms (Gold, Richardson Lucy, Sparse Spike) for the determination of stable DRT solutions and compare their performances. As the promising Sparse Spike deconvolution has a limited scope when using one single regularization parameter, we furthermore replaced the scalar regularization parameter with a vector. The resulting method is able to calculate well-resolved DRT spectra.     

Optimization of thin film solid phase microextraction and data deconvolution methods for accurate characterization of organic compounds in produced water

The continued rise in the extraction of unconventional oil and gas across the globe poses many questions about how to manage these relatively new waste‐streams. Produced water, the primary waste by‐product, contains a diverse number of anthropogenic additives together with the numerous hydrocarbons extracted from the well. Due to potential environmental hazards, it is critical to characterize the chemical composition of this type of waste before proper disposal or remediation/reuse. In this work, a thin film solid phase microextraction approach was developed and optimized to characterize produced water. The thin film device consisted of hydrophilic‐lipophilic balance particles embedded in polydimethylsiloxane and immobilized on a carbon mesh surface. These devices were chosen to provide broad extraction coverage and high reusability. Various parameters were evaluated to ensure reproducible results while minimizing analyte loss. This optimized protocol, consisting of a 15 min extraction followed by a short (3 s) rinsing step, enabled the reproducible analysis of produced water without any sample pretreatment. Extraction efficiency was suitable for both produced water additives and hydrocarbons. The developed approach was able to tentatively identify a total of 201 compounds from produced water samples, by using one‐dimensional gas chromatography hyphenated to mass spectrometry and data deconvolution.