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  • Author or Editor: Sun Han x
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Summary  

We study the stability of Gabor frames with arbitrary sampling points in the time-frequency plane, in several aspects. We prove that a Gabor frame generated by a window function in the Segal algebra S 0(R d) remains a frame even if (possibly) all the sampling points undergo an arbitrary perturbation, as long as this is uniformly small. We give explicit stability bounds when the window function is nice enough, showing that the allowed perturbation depends only on the lower frame bound of the original family and some qualitative parameters of the window under consideration. For the perturbation of window functions we show that a Gabor frame generated by any window function with arbitrary sampling points remains a frame when the window function has a small perturbation in S 0(R d) sense. We also study the stability of dual frames, which is useful in practice but has not found much attention in the literature. We give some general results on this topic and explain consequences to Gabor frames.

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Abstract  

The isoquinoline alkaloids were isolated from traditional Chinese drugs of Phellodendri Cortex, Radix Stephaniae Tetrandrae, Corydalis Yanhusuo and Corydalis Bungeana. The power-time curves of growth of E. coli at different concentrations of isoquinoline alkaloid at 37�C were determined by a 2277 Thermal Activity Monitor. The rate constant of bacteriostastic activity was calculated. The relationship between growth rate constant and concentration was established. The optimum bacteriostastic concentration was determined. Experimental results have indicated that all the isoquinoline alkaloids isolated from the four kinds of traditional Chinese drugs have bacteriostastic activity and the order is Phellodendri Cortex>Radix Stephaniae Tetrandrae>Corydalis Yanhusuo>Corydalis Bungeana.

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The calcination characteristics, sulfation conversion, and sulfation kinetics of a white mud from paper manufacture at fluidized bed combustion temperatures were investigated in a thermogravimetric analyzer. Also, the comparison between the white mud and the limestone in sulfation behavior and microstructure was made. Although the white mud and the limestone both contain lots of CaCO3, they are different in the alkali metal ions content and microstructure. It results in a marked difference in sulfation behavior between the white mud and the limestone. The CaO derived from white mud achieves the maximum sulfation conversion of 83% at about 940 °C which is 1.7 times higher than that derived from limestone at about 880 °C. The shrinking unreacted core model is appropriate to analyze the sulfation kinetics of the white mud. The chemical reaction activation energy E a and the activation energy for product layer diffusion E p for the sulfation of the white mud are 44.94 and 55.61 kJ mol−1, respectively. E p for the limestone is 2.8 times greater than that for the white mud. The calcined white mud possesses higher surface area than the calcined limestone. Moreover, the calcined white mud has more abundant pores in 4–24 nm range which is almost optimum pore size for sulfation. It indicates that the microstructure of the white mud is beneficial for SO2 removal.

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This article analyses Biblical Aramaic (BA) performatives within a prototype approach. The authors demonstrate that BA performatives largely comply with the crosslinguistic prototype and its grammatical and extra-grammatical features. Crucially, although the two ‘tenses’ used, Suffix Conjugation (SC) and Active Participle (AP), exhibit similar frequency in performatives, they differ in distribution: the performative SC is more conventionalised/archaic/typical of Ezra while the performative AP is more productive/innovative/ typical of Daniel. These differences reflect the gradual replacement of SC by AP in performatives due to the profound advancement of the two ‘tenses’ along their respective grammaticalisation paths: the resultative and imperfective paths.

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N,N-dialkylamides having ethyl (DEDOA), butyl (DBDOA) and octyl (DODOA) groups as the alkyl substituents were synthesized in order to investigate their selectivity and capability in the extraction from acidic nitrate media in nuclear reprocessing. The extraction distribution coefficients of U(VI) with the amides in toluene decrease in the order of DODOA>DBDOA>DEDOA. The structure of the extracted species was suggested from the dependence of the distribution ratio on the concentration of the extractant, with the aid of FT-IR spectra. The structural effect on the extraction capability of U(VI) was discussed in terms of the molecular modelling. The effects of temperature on the distribution ratios were also considered, and the extraction reaction enthalpy was calculated.

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Abstract  

The extraction of uranium(VI) from nitric acid by N-octanoylpiperidine (OPPD) in toluene has been investigated at varying concentrations of nitric acid, extractant, salting-out agent LiNO3 and at different temperatures. The mechanism of extraction is discussed in the light of the results obtained. The extracted species have also been investigated using FT-IR spectrometry. The related thermodynamic functions were calculated.

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Abstract  

The extraction performance of uranium(VI) from nitric acid with N-octanoylpiperidine (OPPD) in series of diluents has been investigated. The dependence of extraction distribution on the concentrations of aqueous nitric acid and OPPD and also the temperature has been studied. The experimental results showed that the decreasing order of extraction ability of OPPD is as follows: benzene, dimethyl benzene (DMB), toluene, 1,2-dichloroethene, n-octane, carbon tetrachloride, cyclohexane, chloroform. It cannot be interpreted only on the basis of polarity of the diluents. The interaction between extractant or extracted species and diluent is discussed.

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Objective of this study was to assess the quantification of osteocalcin (OCN) expression by ovine osteoblasts cultured with different concentrations of sodium fluoride (F) and sodium selenite (Se) to evaluate the interaction of these agents on OCN expression in vitro . We wanted to demonstrate a possible protective effect of selenium on the toxic effect of fluoride. Osteoblasts were isolated by complete trypsin and collagenase digestion from ovine calvarial bone and cultured in DMEM supplemented with 15% FBS at 37 °C in a humidified 5% CO 2 incubator. Identified osteoblasts were divided into one control group (C) and eight experimental groups, which were exposed to different concentrations of sodium fluoride (F; 0, 0.5, 1 mM) sodium selenite (Se; 0, 0.1, 1 μM). At different time points after treatment total RNA was extracted and reverse transcribed into first-strand cDNA. OCN mRNA was indirectly measured by real-time fluorescent quantitative PCR (qPCR). OCN mRNA expression in F 1 mM with Se 1 μM group was found to have a high peak at day seven and was lower before and afterwards. Expression of OCN mRNA in all groups except control could be promoted by F and/or Se showing a general upregulation. Furthermore, the toxicity from excessive exposure of osteoblast with F could be circumvented by usage of moderate concentration of Se. Osteoblasts cultured in vitro may have stressful responses to F and Se at the first few days. Low concentrations of Se inhibit the toxic effects of high concentrations of F. Therefore, F and Se could be used as antagonistic factors, which could regulate osteocalcin expression.

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Abstract  

The extraction of uranium (VI) from nitric acid by N-octanoylpyrrolidine (OPOD) in toluene has been investigated at varying concentrations of nitric acid, extractant, salting-out agent LiNO3 and at different temperatures. The mechanism of extraction is discussed in the light of the obtained results.

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Abstract  

The extraction of U(VI) from nitric acid solutions with di-(1-methylheptyl) phosphoric acid has been investigated. The dependence on nitric acid concentration, DMHPA concentration and temperature has been considered and the infra-red spectra of extracted species and extractant were recorded. The mechanism of extraction is discussed in the light of the results obtained.

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