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41.
ExPosition is a new comprehensive R package providing crisp graphics and implementing multivariate analysis methods based on the singular value decomposition (svd). The core techniques implemented in ExPosition are: principal components analysis, (metric) multidimensional scaling, correspondence analysis, and several of their recent extensions such as barycentric discriminant analyses (e.g., discriminant correspondence analysis), multi-table analyses (e.g.,multiple factor analysis, Statis, and distatis), and non-parametric resampling techniques (e.g., permutation and bootstrap). Several examples highlight the major differences between ExPosition and similar packages. Finally, the future directions of ExPosition are discussed. 相似文献
42.
A new model to predict the adsorption equilibrium of mixtures containing supercritical components was presented. The difference in the adsorption mechanism between the supercritical components and the condensable components was accounted for in the new model. Lateral interaction in the adsorbed phase was also considered in the local isotherm. The new model was verified by the experimental data of the mixture CH4/CO2/C2H6 on activated carbon JX101 collected for 283-313 K and pressures up to . It was also verified with the experimental data published previously in literature. Considerable improvement in the prediction precision was achieved in using the new model to predict the adsorption of mixtures on activated carbon. 相似文献
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提出了一种新的简单有效的融合多颜色分量的分割方法,首先在六个不同的颜色空间中选择最佳的待分割颜色分量,然后应用直方图和空间模糊C均值(SFCM)技术对不同颜色分量进行自适应初始分割,最后融合分割结果并进行区域合并。利用该算法在Berkeley图像库上进行了大量实验,实验结果表明,与当前一些经典分割算法Mean-shift、FCR、CTM等相比,利用该方法能够获得更好的分割结果以及更优的性能指标。 相似文献
45.
Phosphorus fractions and adsorption characteristics in grassland soils of varied soil phosphorus status 总被引:2,自引:0,他引:2
Characterization of phosphorus (P) in soils is important both agronomically and environmentally, although the outcome may
depend on the technique applied. Consequently, we evaluated fractionation and adsorption, individually and jointly, and relevant
ancillary soil attributes, to determine the dominant functional characteristics of soil P in 32 fertilized temperate grassland
Inceptisols classified by eight soil series, and by two soil-P index and parent material groups. Residual P was low (30.7%)
and organic P (Po) prominent, 42.0% vs. 17.5% for equivalent soils in unfertilized natural ecosystems. Labile fractions comprised
6.8% inorganic P (Pi) and 9.1% Po. The proportional increase in high vs. low index soils (Morgan P > 6.0 mg l−1 vs. ≤ 6.0 mg l−1) was higher for Pi, and highest for labile and moderately labile fractions. Only moderately labile Pi and Po differed significantly
between soils of limestone and non-limestone origin. Oxalate extractable Fe (Feox) and buffering (EBC) were higher in the latter. The equilibrium P concentration (EPC) was substantially higher in the high
index group, and EBC and binding energy (k) substantially lower, with no significant difference in sorption maximum (Pmax).
EBC equated with weak to strong buffering in different soil series, and conformed better than k to ancillary attributes. Pmax
correlated in order Alox > clay > OC > Feox, and more broadly reflected sorption attributes than oxalate-based sorption capacity (PSC). Principal component (PC) analysis
showed consistent differentiation of P fractions, mostly labile and moderately labile, in PC 1 vs. adsorption and ancillary
attributes in PC 2. However, scatterplots of PC scores showed that adsorption characteristics provided better functional differentiation
than P fractions for distinguishing individual soil series, which may have implications in selection and interpretation of
extractants not only for environmental but also for agronomic soil-tests. 相似文献
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取代基及分子量对非离子型纤维素醚表面特性的影响 总被引:3,自引:3,他引:3
根据Washburn的浸渍理论(Penetration Theory)和van Oss-Good- Chaudhury的组合理论(Combining Theory)及应用柱状灯芯技术(Column Wicking Technique),对几种非离子型纤维素醚,如甲基纤维素、羟丙基纤维素和羟丙基甲基纤维素的表面特性进行了测试。由于这些纤维素醚的取代基、取代度和分子量不同,所以它们的表面能及其组成部分有着明显的差异。数据说明,非离子型纤维素醚Lewis碱大于Lewis酸,表面自由能的主要成分是Lifshitz-van der Waals力。羟丙基的表面能及其成分都大于羟甲基。而在相同取代基和取代度的前提下,羟丙基纤维素的表面自由能正比于分子量;而羟丙基甲基纤维素的表面自由能则正比于取代度,反比于分子量。实验还发现非离子型纤维素醚中的取代基羟丙基和羟丙基甲基的表面能似乎都大于纤维素的表面能,而实验证明所测试得出的纤维素的表面能及其成分的数据是与文献所吻合的。 相似文献
49.
T. Gallina Toschi M. F. Caboni G. Penazzi G. Lercker P. Capella 《Journal of the American Oil Chemists' Society》1993,70(10):1017-1020
Eight samples of cashew nut oil were assayed, and the component triacylglycerols, fatty acids and several unsaponifiable compounds
were analyzed by gas chromatography (GC) and high-performance liquid chromatography (HPLC). Total lipid amount, unsaponifiable
percentage, fatty acids, sterols, triterpene alcohols and tocopherols are reported here. The combination of GC and HPLC enhanced
the resolution of compound classes. 相似文献
50.
本文以蜂窝陶瓷生产工艺为例,讨论了陶瓷部件挤出成型过程中,塑性泥料的制备、成型、干燥和烧成等工艺技术和装备问题。 相似文献