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71.
第四类超Cartan域的Bergman核函数 总被引:13,自引:0,他引:13
显式给出了第四类超Cartan域的Bergman核函数及其全纯自同构群. 相似文献
72.
在二维渗流中,设rn是矩形[O,n]2的最低水平开穿透,令ξn=max{y:(xy)∈rn}.本文证明了在临界状态p=pc时,存在常数0<C1<C2<1,当n充分大时有存在,而在上临界状态p>pc时,有存在]=0. 相似文献
73.
74.
Ying Chen Chang-Ming Ding Tian-Ze Zhou Da-Yong Qi 《Analytical and bioanalytical chemistry》1999,363(1):119-120
An organic solvent-soluble membrane filter (MF) is proposed for the simple and rapid reconcentration with subsequent spectrophotometric determination of trace levels of iron (II) in water. Iron (II) is collected on a nitrocellulose membrane filter as ion associate of an anionic complex, which is formed by iron (II) and Ferrozine and a cation-surfactant. The ion-pair compound and the MF can be dissolved in small volumes of 2-ethoxyethanol and the absorbance of the resulting solution is measured at 560 nm against a reagent blank with molar absorptivity of 4.01 × 104 L mol–1 cm–1. Beer’s law is obeyed over the concentration range 0–10 μg L–1 of iron (II) in water and the detection limit is 0.03 μg L–1 with a 50-fold enrichment factor. The proposed method can satisfactorily be applied to the determination of iron (II) in natural water and sea water. 相似文献
75.
黄先开 《应用数学和力学(英文版)》1999,20(10):1116-1120
IntroductionIntherecentyears,withalotofapplicationsofneuralnetworkmodels,manyauthors[1~3]areinterestedintheresearchofthestructureandperformanceforthesenetworks.BecauseHopfieldneuralnetworkwellsimulatetheecologicalsystem,manystudiesareconcentratedonth… 相似文献
76.
The principal component analysis is an ancient multivariate statistical method[1]. It is extensively used in spectrometry with the popularization of computer and development of the method of chemometrics. It is regarded as an effective method of multivariate statistical analysis. The principal component analysis is universally included in common program package of multivariate statistical analysis. The method, as well as other multivariate calibration methods, combined with artificial neural networks forms the foundation of the chemometrics. 相似文献
77.
卤族元素氟、氯、溴、碘广泛分布在地圈、水圈和生物圈,它们是矿产资源,也是许多地学研究的信息载体,更与人类生活紧密相关.卤族元素分析是地质分析的重要组成部分,而X射线荧光光谱分析方法在当今的卤族元素分析中占有重要地位.本文收集我国1988年—2020年间X射线荧光光谱分析地质材料氟、氯、溴、碘的文献126篇,在简述卤族元... 相似文献
78.
《Particuology》2023
The hydrodynamic behaviour of the spouted bed in the pharmaceutical industries has been found to be less addressed. The present paper has focused on the hydrodynamic characteristics of a spouted bed where the Cellets™ (Ph.Eur./USP) is adopted as the bed material. Experiments are carried out with three different static bed heights (H0) of shallow depth (2Di ≤ H0 < 3Di) using two different particle sizes. The spouted bed employed with Di/D0 of 5 has given the experimental information on external spouting (Ues) by mapping the pressure drop, and fountain height (Hf) against the superficial gas velocity (Ug) is represented with the image contours, which show the intrinsic behaviour. All the 1000 μm and 700 μm particles have been found to exhibit symmetric and asymmetric spouting. With increasing Ug, the fully suspended particles are limited to a certain height in the freeboard region due to the gas-solid cross-flow, which implies the clusters have identified with the image processing method. 相似文献
79.
《Analytica chimica acta》1996,319(3):387-392
The quantitative extraction of iron(III) and gallium(III) was investigated with the recently synthesized macrocyclic Schiff base containing bisphenol A subunits. The phenol groups in the Schiff base moiety led to a large increase in the percent extraction of trivalent metal ions. The substitution of methoxy groups for phenolic OH ligands resulted in a marked decrease in the extractability of metal ions, and no iron(III) was extracted. The corresponding acyclic Schiff base was found to have a reasonable reactivity toward metal ions and a better solubility in organic solvents. The iron(III) and gallium(III) complexes with macrocyclic and acyclic Schiff bases were quantitatively extracted into nitrobenzene without the presence of bulky counter anions. A single extraction gave a good separation of iron(III) from iron(II) in the mole ratios 4:1 to 1:3. The red iron(III) complexes can be used for the extraction-spectrophotometric determination of iron(III). The apparent molar absorptivity at 518 nm is 5.43 × 103lmol−1 cm−1. 相似文献
80.