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61.
应用独立分量分析(ICA)方法对海底管道缺陷漏磁法检测中电磁干扰的消除进行了研究,阐述了漏磁检测和负熵法ICA快速算法的原理,应用相应的分析工具研究了试验数据。结果表明,在试验室条件下该方法能很好地分离出缺陷信号和电磁干扰信号。 相似文献
62.
D. Oleszak E. Jartych A. Antolak M. Pkaa M. Szymaska M. Budzyski 《Journal of Alloys and Compounds》2005,400(1-2):23-28
X-ray diffraction, Mössbauer spectroscopy and magnetization measurements were used to study the structure and some magnetic properties of Fe50Ge50 and Fe62Ge38 prepared by mechanical alloying from the elemental powders. In both cases in the early stages of milling the intermediate paramagnetic FeGe2 phase was formed. The mechanical alloying process of Fe50Ge50 resulted in the formation of the paramagnetic FeGe (B20) phase with an average crystallite size of about 15 nm. In the case of the Fe62Ge38, the ferromagnetic Fe5Ge3 (β) phase with a Curie temperature of about 430 K was obtained. The average crystallite size was about 9 nm. The average hyperfine magnetic field of about 16 T allowed it to determine that more than four germanium atoms exist in the nearest environment of the 57Fe isotopes in the Fe5Ge3 phase. 相似文献
63.
Romina Combi Maria Salsone Chiara Villa Luigi Ferini-Strambi 《International journal of molecular sciences》2021,22(8)
Dementia with Lewy bodies (DLB) is one of the most common causes of dementia and belongs to the group of α-synucleinopathies. Due to its clinical overlap with other neurodegenerative disorders and its high clinical heterogeneity, the clinical differential diagnosis of DLB from other similar disorders is often difficult and it is frequently underdiagnosed. Moreover, its genetic etiology has been studied only recently due to the unavailability of large cohorts with a certain diagnosis and shows genetic heterogeneity with a rare contribution of pathogenic mutations and relatively common risk factors. The rapid increase in the reported cases of DLB highlights the need for an easy, efficient and accurate diagnosis of the disease in its initial stages in order to halt or delay the progression. The currently used diagnostic methods proposed by the International DLB consortium rely on a list of criteria that comprises both clinical observations and the use of biomarkers. Herein, we summarize the up-to-now reported knowledge on the genetic architecture of DLB and discuss the use of prodromal biomarkers as well as recent promising candidates from alternative body fluids and new imaging techniques. 相似文献
64.
Robin Wijngaard Meritxell Perramn Marina Parra-Robert Susana Hidalgo Gina Butrico Manuel Morales-Ruiz Muling Zeng Eudald Casals Wladimiro Jimnez Guillermo Fernndez-Varo Gerald I. Shulman Gary W. Cline Gregori Casals 《International journal of molecular sciences》2021,22(9)
The metabolic ratios lactate/pyruvate and β-hydroxybutyrate/acetoacetate are considered valuable tools to evaluate the in vivo redox cellular state by estimating the free NAD+/NADH in cytoplasm and mitochondria, respectively. The aim of the current study was to validate a gas-chromatography mass spectrometry method for simultaneous determination of the four metabolites in plasma and liver tissue. The procedure included an o-phenylenediamine microwave-assisted derivatization, followed by liquid-liquid extraction with ethyl acetate and silylation with bis(trimethylsilyl)trifluoroacetamide:trimethylchlorosilane 99:1. The calibration curves presented acceptable linearity, with a limit of quantification of 0.001 mM for pyruvate, β-hydroxybutyrate and acetoacetate and of 0.01 mM for lactate. The intra-day and inter-day accuracy and precision were within the European Medicines Agency’s Guideline specifications. No significant differences were observed in the slope coefficient of three-point standard metabolite-spiked curves in plasma or liver and water, and acceptable recoveries were obtained in the metabolite-spiked samples. Applicability of the method was tested in precision-cut liver rat slices and also in HepG2 cells incubated under different experimental conditions challenging the redox state. In conclusion, the validated method presented good sensitivity, specificity and reproducibility in the quantification of lactate/pyruvate and β-hydroxybutyrate/acetate metabolites and may be useful in the evaluation of in vivo redox states. 相似文献
65.
66.
Angular-dependent magnetic Barkhausen noise measurements were performed on ASTM 36 steel samples for various values of applied uniaxial stress. The maximum differential permeability and the coercive field are obtained from this Barkhausen signals. The angular dependence of these macroscopic magnetic properties is studied. The tension for which the magneto-elastic energy balances the anisotropic energy is estimated. The results are discussed based on the domain wall theory. 相似文献
67.
The effect of tempering on the magnetic Barkhausen noise (MBN) signal profile was studied in case-carburised EN36 steel using a range of magnetic excitation frequencies and a number of frequency ranges for analysis of the MBN signal. The MBN level generally increases with tempering due to coarsening of the microstructure. With higher values of excitation frequency, fEX, the MBN profile exhibits a single peak, but with low values of fEX, double peaks are observed. The MBN peak obtained with higher fEX was found to correlate well with hardness changes in a region, down to 100 μm below the surface. The analysis of the MBN signal produced with low fEX, in narrow frequency ranges selected by software frequency filtering, showed variations in the extent of changes in the relative height of the two MBN peaks in the profile. After taking into account the skin depth-frequency relation for the MBN signal, variations in the values of the two MBN peaks in different analysing frequency ranges were found to correlate well with hardness variations at different depths down to 425 μm below the surface. An empirical relationship has been established between the hardness-depth profile and the MBN measurements. 相似文献
68.
对磁粉探伤标准中所表述的电磁轭提升力涵义有两种不同的理解,一为提升力仅是对设备的要求,而与灵敏度无关;二为提升力与灵敏度紧密相关。对该两种理解进行分析讨论,认为第二种理解更合乎其原意。 相似文献
69.
Many processing techniques, such as hot dip aluminizing, bimetal formation, liquid metal corrosion, cementing, welding and diffusion bonding, are basically dependent on interfacial reactions [1-3]. It is therefore important to investigate the formation and growth of intermetallic layers at the interface. There have been several studies carried out to examine chemical compositions and growth kinetics of intermetallic layers in the Al-Fe system [4-9]. Most authors have come to an agreement that… 相似文献
70.
高强度钢焊接裂纹检测及其成因分析 总被引:1,自引:0,他引:1
为了充分认识高屈强比、高强度低温材料焊接裂纹的敏感性,通过对NK—HIT—EN610U2L低合金高强度钢球罐支柱角焊缝裂纹的检测、解剖对比和成因分析,发现焊缝外表面缺陷与内部焊接缺陷存在一定关系,高应力设计部位比较突出,因此检测与焊接要引起高度注意。 相似文献