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31.
Mathematical Notes - This article has been retracted at the request of the Editorial Board of the journal in accordance with the COPE guidelines. This article contains a significant amount of... 相似文献
32.
Let (R,m) be a commutative Noetherian regular local ring of dimension d and I be a proper ideal of R such that mAss R (R/I) = Assh R (I). It is shown that the R- module Hht(I) I (R) is I-cofinite if and only if cd(I,R) = ht(I). Also we present a sufficient condition under which this condition the R-module H i I (R) is finitely generated if and only if it vanishes. 相似文献
33.
Bahram Mokhtari Kobra Pourabdollah Naser Dallali 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(3):921-934
Calixarenes has been subject to extensive research in development of many extractants, transporters, stationary phases, electrode ionophores and optical and electrochemical sensors over the past four decades. In this paper, the nuclear applications of calixarenes are summarized in six fields including complexation studies, solvent extraction, membrane transport, chromatography, luminescent and colorimetric applications, and electroanalytical applications. In the first to fourth sections, the extractability, extraction equilibria and extraction constants of lanthanide, actinide and other nuclear waste cations ions, which were subjected to solvent extraction by the macrocyclic ligands, are reviewed. In two last sections, the analytical applications of calixarene complexes towards nuclear waste cations, including spectroscopic and electroanalytic sensors, are discussed. The examples described in this review illustrate the potential of calixarene derivatives in the rapidly growing field of cations recognition in nuclear wastes. 相似文献
34.
The strong affinity of natural ionic polysaccharides for certain metal ions is exploited in the design of a new class of voltammetric sensing devices. In particular, carbon-paste electrodes containing pectic and alginic acids are used for the nonelectrolytic collection and subsequent voltammetric determination of copper and lead, respectively. Cyclic and differential pulse voltammetry are used to quantify the accumulated ions. The response is characterized with respect to modifier loading, preconcentration period, metal concentration, reproducibility, possible interferences and other variables. Titrimetric experiments illustrate the potential of polysaccharide electrodes for speciation work. Preliminary data are also given for analogous measurements of copper at heparin-modified electrodes. Detection limits are 1 mug/ml and the relative standard deviation is 4.8%. 相似文献
35.
Urea (U) and salicylic acid (SA) crystallize from aqueous solution as a 11 adduct whose structure shows them to be linked via several weak and one strong hydrogen bonds. The ir spectra of the adduct and its deuterated counterpart have been analyzed and the stretching modes of the various hydrogen bonds identified. The1H and13C nmr. spectra are also interpreted to show that discrete adducts of U·SA persist in solution. On heating, U·SA decarboxylates at a much lower temperature than SA itself. 相似文献
36.
Naser Zamani 《代数通讯》2013,41(4):1297-1307
Let (R,𝔪) be a local ring and s ≥ ?1. Using the notion of M-sequence in dimension > s, we introduce Cohen–Macaulay modules in dimension > s. Among other things concerning Cohen–Macaulay modules in dimension > s, some finiteness results of the support and the associated primes of local cohomology modules are investigated. 相似文献
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Basically there exists a significant interest in dynamic friction models [1]. These dynamic models describe μ as a time dependent process parameter. The indentification of the belonging parameters needs a special kind of measurements. This is due to the fact that the measurements with the classical pin on disk arrangement give stationary values of μ only, the measurements of dynamic properties are even infeasible. A new advanced tribometer has been developed. This tribometer allows measurements of complex unsteady friction processes. The experimental characteristics and the realization of this novel tribometer are presented by concrete measurements. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
40.
Ramin Maleki Nasim Mohammad Nezhad Naser Samadi Khalil Farhadi 《Mikrochimica acta》2009,165(1-2):97-101
Dispersive liquid–liquid microextraction (DLLME) in conjunction with high-performance liquid chromatography-diode array detection (HPLC-DAD) has been applied to the extraction and determination of EDTA in sediments and water samples. The effect of extraction, nature and volume of disperser solvent, pH value of sample solution, extraction time and extraction temperature were investigated. Under the optimal conditions the analytical range of EDTA was from 3.0 to 50.0 μg L?1 with a correlation coefficient of 0.9982 and a detection limit of 1.7 μg L?1. The relative standard deviation (RSD) was less than 5.4% (n?=?5), and the recovery values were in the range of 89–95%. The simplicity, high enrichment, high recovery and good repeatability are the main advantages of the method presented. The DLLME-HPLC-DAD method was successfully applied to the analysis of EDTA in aqueous samples. 相似文献