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排序方式: 共有138条查询结果,搜索用时 15 毫秒
1.
In this paper, the deconvolution of SIMS profiles analysed at very low primary energy (0.5 keV/O2+) is addressed. The depth resolution function (DRF) of the SIMS analysis in presence of roughness is established and a deconvolution procedure is implemented without or in presence of roughness on samples containing delta-doped layers of boron in silicon. It is shown that the deconvolution procedure can lead to a great improvement of the full width at half maximum (FWHM) of the measured peaks in the case where no roughness in detected in the crater bottom. In the case where it is present, the conditions required to use a deconvolution procedure are discussed, and the deconvolution is implemented using precise and restrictive assumptions. 相似文献
2.
Ravi Shankar Anubhav Saxena Ajaib S. Brar 《Journal of organometallic chemistry》2002,650(1-2):223-230
New functional polysilanes [R2R1Si(CH2)2SiH]n (R=Me, R1=H (1); R=R1=Et (2); R=Me, R1=Ph (3)) bearing carbosilyl side chains have been synthesized by catalytic dehydropolymerization of precursor carbosilanes R2R1SiCH2CH2SiH3 using Cp2TiCl2–BuLi as a catalyst. These polymers are characterized by 1H, 13C, 29Si, {1H–29Si} HSQC NMR spectroscopy, GPC and TGA. Attempts to delineate the tacticity from the analysis of deconvoluted 29Si{1H}-NMR signals associated with the side chain silicon atoms reveal that the triad concentration ratio follows a Bernoullian statistical model for polymers 1 and 2 only. 相似文献
3.
Summary The effects of concentration, separation and spectral similarity as factors influencing the accuracy of iterative target testing
factor analysis (ITT-FA) are investigated for three component systems by the application of analysis of variance (ANOVAR).
ANOVAR is applied over a range of peak separations to map the changing effects of the three factors with increasing overlap.
Two error responses were measured and analysed, (a) Relative cluster error (RCE) a measure of the error over all peaks in
a cluster and (b) Relative peak error (RPE) the error of an individual peak. Multicomponent analysis (MCA) a method requiringa priori spectral information, is used as a referee method for ITT-FA. 相似文献
4.
Detection of delamination defects in CFRP materials using ultrasonic signal processing 总被引:3,自引:0,他引:3
In this paper, signal processing techniques are tested for their ability to resolve echoes associated with delaminations in carbon fiber-reinforced polymer multi-layered composite materials (CFRP) detected by ultrasonic methods. These methods include split spectrum processing (SSP) and the expectation-maximization (EM) algorithm. A simulation study on defect detection was performed, and results were validated experimentally on CFRP with and without delamination defects taken from aircraft. Comparison of the methods for their ability to resolve echoes are made. 相似文献
5.
Mathematical deconvolution methods can separate co-eluting peaks in samples for which (chromatographic) separation fail. However, these methods often heavily rely on manual user-input and interpretation. This is not only time-consuming but also error-prone and automation is needed if such methods are to be applied in a routine manner. 相似文献
6.
Raman and IR spectroscopy have been used to elucidate the solvation process in a mixed water-acetonitrile solvent in the CN stretching region. The number and positions of the components forming the spectral contour are established by Fourier deconvolution and Factor analysis and their areas are determined by fitting. The forms of existence of acetonitrile in the mixed solvent are discussed. 相似文献
7.
Here we present a simple yet effective gas chromatography-mass spectrometry (GC-MS) identification approach for the detection of heteroatom-containing compounds (HACCs) in petroleum fractions. The MS/AMDIS (Automated Mass Spectral Deconvolution and Identification System) program was used to identify parts per million (ppm) HACC concentrations in petroleum fractions in place of traditional techniques (extraction and standard injection). Polycyclic aromatic sulfur heterocycles (S-PAHs) were used as model compounds to confirm the validity of the AMDIS identifiers, which were compared with extracted results using the off-line X-calibur software. AMDIS was able to identify ppm concentrations of S-PAHs in oil condensate. There was good agreement between experimental and AMDIS identification results for S-PAHs in oil condensate. AMDIS was also used to detect nitrogen-containing compounds (NCCs) and alkylphenols in oil condensate. Our results confirmed the presence of 2-methylbenzothiazole, carbazole, and 2,4-ditertbutyl phenol. In a crude oil sample, AMDIS identification of m/z=191 biomarkers was consistent with empirical results. Therefore, AMDIS can help to reduce the number of experimental steps in identification protocols. 相似文献
8.
气相色谱-质谱数据的后处理 总被引:6,自引:0,他引:6
气相色谱-质谱(gaschromatography/massspectrometry)以其优异的分离定性特点,被广泛地应用于分析复杂混合物中的挥发性组分。然而,其质谱图会包含一些来自于离子源污染物、柱流失物、基质干扰物所产生的离子,导致定性准确性降低。在分析复杂基质中的痕量物质时,这一现象尤为突出。例如,在食品中农药多残留的分析中,为了确保各种极性的农药都有很好的回收,样本中的基质就会不可避免地被引入检测过程中,对目标化合物的质谱图产生严重的干扰。同时某些保留时间相近的化合物的质谱图也会叠加在一起,互相干扰。这些问题的存在使农药确认变得更为困难。因此,通过对质谱数据的后处理,将目标化合物的质谱图从原始谱图中提取出来,根据新建的"纯净"的质谱图对目标化合物进行确证将更有实际应用价值。 相似文献
9.
10.
Performance of laser-ultrasonic F-SAFT imaging 总被引:1,自引:0,他引:1
The resolution and signal-to-noise ratio of laser-ultrasonics to detect small and buried defects can be greatly enhanced by using the synthetic aperture focusing technique (SAFT). Originally developed in the time domain, SAFT can also be implemented in the frequency domain (F-SAFT) using the angular spectrum approach for a significant reduction in processing time. In this paper, an F-SAFT based data processing method especially adapted to laser-ultrasonic data is presented. This method allows for further significant improvements towards laser-ultrasonic imaging of small defects. It includes temporal deconvolution of the waveform data, control for an optimal aperture and frequency bandwidth as well as spatial interpolation of the subsurface images. All the above operations are well adapted to the frequency domain calculations and embedded in the F-SAFT data processing. Also, the aperture control and spatial interpolation allow a reduction of sampling requirements to further decrease both inspection and processing times. The above improvements are illustrated using laser-ultrasonic data taken from an aluminum sample with flat-bottom holes. 相似文献