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151.
We present predictions for nucleon-nucleon elastic scattering phase parameters based on a unitary, relativistic, one-pion-exchange model, which takes single-pion-production inelasticity into account. The agreement of the high-L phase shifts with data is considerably improved at intermediate energies by inclusion of the NΔ inelastic channel. Our predicted inelasticities are in generally good agreement with the data, but are smaller than the predictions of Green and Sainio. The Argand plots of the 1D2, 3F3, 3P1, and 1G4 all show counterclockwise motion resulting from the onset of inelastic channels. 相似文献
152.
Amorn Slosse Filip Van Durme Nele Samyn Debby Mangelings Yvan Vander Heyden 《Molecules (Basel, Switzerland)》2021,26(21)
Cannabis sativa L. is widely used as recreational illegal drugs. Illicit Cannabis profiling, comparing seized samples, is challenging due to natural Cannabis heterogeneity. The aim of this study was to use GC–FID and GC–MS herbal fingerprints for intra (within)- and inter (between)-location variability evaluation. This study focused on finding an acceptable threshold to link seized samples. Through Pearson correlation-coefficient calculations between intra-location samples, ‘linked’ thresholds were derived using 95% and 99% confidence limits. False negative (FN) and false positive (FP) error rate calculations, aiming at obtaining the lowest possible FP value, were performed for different data pre-treatments. Fingerprint-alignment parameters were optimized using Automated Correlation-Optimized Warping (ACOW) or Design of Experiments (DoE), which presented similar results. Hence, ACOW data, as reference, showed 54% and 65% FP values (95 and 99% confidence, respectively). An additional fourth root normalization pre-treatment provided the best results for both the GC–FID and GC–MS datasets. For GC–FID, which showed the best improved FP error rate, 54 and 65% FP for the reference data decreased to 24 and 32%, respectively, after fourth root transformation. Cross-validation showed FP values similar as the entire calibration set, indicating the representativeness of the thresholds. A noteworthy improvement in discrimination between seized Cannabis samples could be concluded. 相似文献
153.
On the basis of empirical data, power-law boundary relations are formulated to delineate the splash and non-splash regions
on dry surfaces or thin films under isothermal conditions, using the Ohnesorge and Reynolds numbers. Approximation of the
relations permits cancellation of fundamental fluid physical constants to give simplified formulas which provide insight into
the governing parameters describing splashing and non-splashing behaviors. Thus, for a droplet impinging upon a dry solid
surface, the splash/non-splash border is well described by √Ca = 0.35. For a drop impinging upon a thin fluid film, the analytical
simplification yields a boundary described by √We = 20. For both expressions, values greater than the numerical value result
in splashing. 相似文献
154.
We investigate the suggestion of R.L. Dobrushin, that for many examples of non-Gibbsian measures, a well-defined interaction
potential can still be derived.
Such an interaction cannot be absolutely summable, uniformly in all configurations. Rather there will exist a typical set
of configurations on which the interaction decays sufficiently fast. We show how to construct an interaction, using quite
elementary methods, for example of the restriction of the Ising pure phases to one layer of the lattice.
We sketch a general setup, showing that there is an intimate relation between the problem treated here and the decay of correlations
in certain disordered systems.
Received: 27 March 1996 / Accepted: 29 July 1996 相似文献
155.
156.
N. Armenise M. Calicchio O. Erriquez M.T. Fogli-Muciaccia S. Natali S. Nuzzo F. Romano R. Belusevic D.C. Colley G.T. Jones S. ONeale S.J. Sewell M.F. Votruba D. Bertrand J. Moreels J. Sacton C. Vander Velde-Wilquet M.A. Parker 《Physics letters. [Part B]》1981,102(5):374-380
Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipped with a TST. Using a method independent of both the neutrino flux and nuclear interaction corrections, the ratio R= σn/σp has been measured. The result is R=1.98±0.19 for the ratio of total cross sections. Bjorken x distributions for proton and neutron targets and for u and d quarks are compared. 相似文献
157.
Developing an analytical separation procedure for an unknown mixture is a challenging issue. An important example is the separation and quantification of a new drug and its impurities. One approach to start method development is the screening of the mixture on dissimilar chromatographic systems, i.e. systems with large selectivity differences. After screening, the most suited system is retained for further method development. In a step prior to such strategy dissimilar chromatographic systems need to be selected. In this paper the performance of different chemometric selection approaches, described in the literature, was visually evaluated and compared. Additionally, orthogonal projection approach (OPA) was tested as another potential selection method. All techniques, including the OPA method, were able to select (a set of) dissimilar chromatographic systems and many similarities between the selections were observed. However, the Kennard and Stone algorithm performed best in selecting the most dissimilar systems in the earliest steps of the selection procedure. The generalized pairwise correlation method (GPCM) and the auto-associative multivariate regression trees (AAMRT) were also performing well. OPA and weighted pair group method using arithmetic averages (WPGMA) are less preferable. 相似文献
158.
159.
Simultaneous determination of five common additives in insulating mineral oils by high‐performance liquid chromatography with ultraviolet and coulometric detection 下载免费PDF全文
Maria Concetta Bruzzoniti Corrado Sarzanini Luca Rivoira Vander Tumiatti Riccardo Maina 《Journal of separation science》2016,39(15):2955-2962
Dielectric mineral oils are used to impregnate power transformers and large electrical apparatus, acting as both liquid insulation and heat dissipation media. Antioxidants and passivators are frequently added to mineral oils to enhance oxidation stability and reduce the electrostatic charging tendency, respectively. Since existing standard test methods only allow analysis of individual additives, new approaches are needed for the detection of mixtures. For the first time we investigate and discuss the performance of analytical methods, which require or do not require extraction as sample pretreatment, for the simultaneous reversed‐phase high‐performance liquid chromatography determination of passivators (benzotriazole, Irgamet® 39) and antioxidants (N‐phenyl‐1‐naphtylamine, 2,6‐di‐tert‐butylphenol, 2,6‐di‐tert‐butyl‐p‐cresol), chosen for their presence in marketed oils. Quick easy, cheap, effective, rugged and safe and solid phase extractions were evaluated as sample pretreatments. Direct sample‐injection was also studied. Ultraviolet spectrophotometry and direct‐current coulometry detection were explored. As less prone to additive concentrations variability, the direct‐injection high‐performance liquid chromatography with ultraviolet and coulometric detection method was validated through comparison with Standard Method IEC 60666 and through an ASTM interlaboratory proficiency test. Obtained detection limits are (mg kg?1): benzotriazole (2.8), Irgamet® 39 (13.8), N‐phenyl‐1‐naphtylamine (11.9), 2,6‐di‐tert‐butylphenol (13.1), 2,6‐di‐tert‐butyl‐p‐cresol (10.2). Simultaneous determination of selected additives was possible both in unused and used oils, with good precision and accuracy. 相似文献
160.
Robust partial least squares model for prediction of green tea antioxidant capacity from chromatograms 总被引:1,自引:0,他引:1
In this paper a robust version of the partial least squares model (partial robust M-regression, PRM) was built to predict the total antioxidant capacity of green tea extracts. In order to construct a calibration model, chromatograms obtained by a fast high-performance liquid chromatographic method on a monolithic silica column were related with the total antioxidant capacity of green tea extracts as determined by the Trolox antioxidant capacity method. Since natural samples are the subject of the study, some outlying samples are present in the data, as shown in an earlier work. Therefore, to construct reliable calibration models, they were detected and removed prior to modeling. With the applied robust partial least squares approach, where a weighting scheme is embedded to down-weight the negative influence of outliers upon the model it is possible to construct a robust calibration model, without prior identification of outlying objects. It was shown that a robust model, allowing satisfactory prediction for test samples, can be used in controlling green tea antioxidant capacity based on their chromatograms. The constructed robust partial least squares model was shown to have virtually the same fit and predictive power as the classical partial least squares model when outlying samples were removed from the data. 相似文献