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61.
This paper is concerned with blind source separation in nonlinear models. Special attention is paid to separability issues. Results show that separation is impossible in the general case. However, for specific nonlinear models, the problem becomes tractable. A generic set of parametric nonlinear mixtures is considered: This set has the Lie group structure (a group structure with continuous binary operation). In the parameter set, a definition of a relative gradient is given and is used to design both batch and stochastic algorithms. For the latter, it is shown how a proper use of the relative gradient leads to equivariant adaptive algorithms 相似文献
62.
Extended AMR-WB for high-quality audio on mobile devices 总被引:2,自引:0,他引:2
Salami R. Lefebvre R. Lakaniemi A. Kontola K. Bruhn S. Taleb A. 《Communications Magazine, IEEE》2006,44(5):90-97
This article presents the architecture, performance, and application scenarios of the AMR-WB+ (extended AMR-WB) audio codec, which provides high quality at exceptionally low rates, and consistent quality over all audio types. This codec was recently selected by 3GPP and DVB to support low-bit-rate audio and audiovisual applications on mobile networks. 相似文献
63.
M.C. Terkhi F. Taleb P. Gossart A. Semmoud A. Addou 《Journal of photochemistry and photobiology. A, Chemistry》2008,198(2-3):205-214
An interaction between humic acid, an organic part of soil and mercury was studied by Fourier transform infrared spectroscopy (FTIR) and by ICP-AES analysis under given pH and concentration conditions. First the spectroscopic model was validated on the interaction of simple molecules representing the structural components of humic acid such as benzoic acid, catechol and salicylic acid with mercury. The interaction of carboxylic parts of humic acid with mercury is very interesting and easily characterised by infrared spectroscopy, an ideal mean for molecular study. Under the salt form (commercial humic acid Fluka TM: FHA), humic acid reacts with mercury in a different way from its acid form (FHA purified noted PFHA) and the Leonardite (LHA). Because of the straightforward exchange between Na+, Ca2+ and Hg2+, fixation of the latter is much more important with the salt form (FHA). However, this reaction is reduced under the acid form (PFHA, LHA) because the exchange with protons is difficult. The effect of this exchange was studied by FTIR showing the intensity decrease of νCO (COOH), the carboxylic functional group band of the acid, and the shifting of νas (COO−), the carboxylate functional group band under given pH and mercury conditions. For the FHA salt form, the characteristic band νCO (COOH) represented by a shoulder did not evolute, whereas the corresponding band to νas (COO−) strongly shifted (40 cm−1) for a maximum Hg2+ concentration (1 g l−1). On the other hand, for the acid form (PFHA, LHA), the intense band of νCO (COOH) disappeared proportionally to the increase of Hg2+concentration and the νas (COO−) band moved for about 20 cm−1. The same results were reached with pH variations. Our results were confirmed by ICP-AES mercury analysis. This study shows that humic acids react differently according to their chemical and structural state. 相似文献
64.
Dr. Gourishetty Srikanth Dr. Anil Ravi Dr. Anusha Sebastian Jobi Joseph Prof. Monther A. Khanfar Prof. Mohammed I. El-Gamal Prof. Raed A. Al-Qawasmeh Prof. Ihsan A. Shehadi Scott McN. Sieburth Prof. Imad A. Abu-Yousef Prof. Amin F. Majdalawieh Prof. Taleb H. Al-Tel 《European journal of organic chemistry》2023,26(13):e202300080
The discovery of novel small molecules endowed with high 3D-content remains a powerful tool for interrogating underrepresented biological space. To this end, the pseudo-natural products (pseudo-NP) strategy has become one of the most important tools to deliver biologically significant chemical probes. In this article, we describe the development of a new class of pseudo-NP collection, through connecting tryptamines with a furanose derivative followed by subjecting the product from this operation to a ring distortion strategy that led to diastereoselective synthesis of camptothecin-like compounds. This process is driven by a cascade that unites Pictet–Spengler reaction with Michael addition reaction, followed by oxidative-ring enlargement and subsequent transannular aldol cyclization delivering camptothecin-like architectures. The obtained diastereoselectivity was verified using density functional theory (DFT) calculations. 相似文献
65.
66.
Rasheed Rashed Taleb Mansoor Hadeel S. Abdullah Thamer Adnan Juzsakova Tatjana Al-Jammal Noor Salman Ali Dawood Al-Shaikhly Rasha R. Le Phuoc Cuog Domokos Endre Abdulla Thaer A. 《Journal of Thermal Analysis and Calorimetry》2021,145(2):297-307
Journal of Thermal Analysis and Calorimetry - This paper deals with an advanced colorimetric method used to determine the catalase mimetic activity of V2O5 nanoparticles by measuring the decrease... 相似文献
67.
68.
Urolithiasis can lead to the loss of renal function in some cases. In this study, we tested the inhibiting effect of wheat bran (Triticum aestivum L) extract on calcium oxalate crystallization in a turbidimetric model, by FTIR spectroscopy, and polarized microscopy. The results show that this plant extract has a major inhibitory effect on calcium oxalate crystallization. 相似文献
69.
A.F. Qasrawi Faten G. AljammalNisreen M. Taleb N.M. Gasanly 《Physica B: Condensed Matter》2011,406(14):2740-2744
TlInSe2 single crystal has been successfully prepared by the Bridgman crystal growth technique. The crystal, which exhibits compositional atomic percentages of 25.4%, 25.2% and 49.4% for Tl, In and Se, respectively, is found to be of tetragonal structure with lattice parameters of a=0.8035 and c=0.6883 nm. The crystals were used to design radio frequency sensitive varactor device. The temperature dependence of the current-voltage characteristics of the device allowed the calculation of the room temperature barrier height and ideality factor as 0.87 eV and as 3.2, respectively. Rising the device temperature increased the barrier height and decreased the ideality factor. This behavior was attributed to the current transport across the metal-semiconductor interface. The capacitance of the device is observed to increase with increasing voltage and increasing temperature as well. The temperature activation of the capacitance starts above 82 °C with a temperature coefficient of capacitance being 1.08×10−3 K−1. Furthermore, the capacitance of the device was observed to increase with increasing frequency up to a maximum critical frequency of 4.0 kHz, after which the capacitance decreased with increasing frequency. The behavior reflected the ability of maximum amount of charge holding being at a 4.0 kHz. The analysis of the capacitance-voltage characteristics at fixed frequencies reflected a frequency dependent barrier height and acceptors density. The decrease in the barrier height and acceptors density with increasing frequency is mainly due to the inability of the free charge to follow the ac signal. 相似文献