排序方式: 共有14条查询结果,搜索用时 187 毫秒
1.
2.
Saloua Ghedamsi 《Accreditation and quality assurance》2009,14(11):619-621
The concept of metrology first appeared in Tunisia towards 1909. At the end of the 1990s, bodies for evaluating conformity
of measurement at different levels have been instituted to meet calibration and testing needs of the national industry. These
bodies were divided into three categories: Class A where we find mainly the Central Laboratory for Analysis and Testing LCAE
and the National Defence Laboratory DEFNAT; these two laboratories are in charge of the technological upgrading of the other
bodies of Class B which, in turn, would transfer their knowledge to the industries, the latter constituting Class C. Nowadays,
the accreditation of Tunisian laboratories at the international level by recognized reference foreign bodies and participation
in the European proficiency network enabled the national laboratories of Tunisia to establish the degree of equivalence between
their measurement results and those of other foreign laboratories. 相似文献
3.
Redouan El Khamlichi Dounia Bouchta Mounia Ben Atia Mohamed Choukairi Riffi Temsamani Khalid Ihssane Raissouni Saloua Tazi Ahrouch Mohammadi Abdellatif Soussi Khalid Draoui Chaouket Faiza Mohammed Lamarti Sefian 《Journal of Solid State Electrochemistry》2018,22(7):1983-1994
Normetanephrine is a marker for pheochromocytoma, a rare catecholamine-secreting and neuroendocrine tumor, that arises from sympathetic and parasympathetic paraganglia. In this work, a novel carbon/chitosan electrode paste was used for sensitive voltammetric determination of normetanephrine and dopamine in the presence of ascorbic acid and uric acid. The modified electrode has shown an increase in the effective area of up to 68%, well-separated oxidation peaks, and an excellent electrocatalytic activity. The electrochemical response characteristics were investigated by cyclic and differential pulse voltammetry. Interestingly, high sensitivity and selectivity in the linear range of normetanephrine, dopamine, ascorbic acid, and uric acid concentrations were observed. The present method was applied in the urine sample and satisfactory results were obtained showing that this electrode is very suitable in pharmaceutical and clinical preparations. 相似文献
4.
Bouafsoun A Helali S Othmane A Kerkeni A Prigent AF Jaffrézic-Renault N Bessueille F Léonard D Ponsonnet L 《Macromolecular bioscience》2007,7(5):599-610
To study cell attachment to biomaterials, several proteins such as fibronectin, collagen IV, heparin, immunoglobulin G, and albumin have been deposited onto polystyrene adsorbed on a self-assembled monolayer (silane or thiol) on glass or gold, respectively. The different steps of this multilayer assembly have been characterized by electrochemical impedance spectroscopy (EIS). These data are compared to those of adhesion rate, viability percentage, and cytoskeleton labeling for a better understanding of the cell adhesion process to each protein. All the proteins are endothelial cell adhering biomolecules but not with the same features. A linear relationship has been established between adhesion rate and resistance of the endothelial cell/protein interface for all negatively charged proteins. 相似文献
5.
Summary. This paper describes the numerical analysis of a time dependent linearised fluid structure interaction problems involving
a very viscous fluid and an elastic shell in small displacements. For simplicity, all changes of geometry are neglected. A
single variational formulation is proposed for the whole problem and generic discretisation strategies are introduced independently
on the fluid and on the structure. More precisely, the space approximation of the fluid problem is realized by standard mixed
finite elements, the shell is approximated by DKT finite elements, and time derivatives are approximated either by midpoint
rules or by backward difference formula.
Using fundamental energy estimates on the continuous problem written in a proper functional space, on its discrete equivalent,
and on an associated error evolution equation, we can prove that the proposed variational problem is well posed, and that
its approximation in space and time converges with optimal order to the continuous solution.
Received May 14, 1999 / Revised version revised October 14, 1999 / Published online July 12, 2000 相似文献
6.
Mathieu Lazerges Kathleen Isabelle Chane-Ching Salah Aeiyach Saloua Chelli Brigitte Pepin-Donat Martial Billon Christian Lombard François Maurel Mohamed Jouini 《Journal of Solid State Electrochemistry》2009,13(2):231-238
The electrochemical oxidation of hexa-N-pyrrolylbenzene in organic media leads, via intramolecular coupling of the pyrrole residues, to the deposition of a molecular
semiconductor film on an electrode surface. In situ electron spin resonance–electrochemical experiments reveal that the semiconductor
is endowed with both properties of conducting polymers (i.e., reversible oxidation) and polyaromatic molecular materials (i.e., highly paramagnetic). The material, which is easy to process as soft homogeneous thin film, shows a tunable 0 to 1 spin
concentration per molecule at room temperature by controlling the electrochemical potential.
Contribution to the Fall Meeting of the European Materials Research Society, Symposium D: 9th International Symposium on the
Electrochemical–Chemical Reactivity of Metastable Materials, Warsaw, 17th–21st September, 2007.
An erratum to this article can be found at 相似文献
7.
Saloua Chelli Mustapha Majdoub Salah Aeiyach Mohamed Jouini 《Journal of polymer science. Part A, Polymer chemistry》2009,47(17):4391-4399
A polyrotaxane in which β‐cyclodextrins (β‐CDs) are threaded onto a polyether chain was prepared by polycondensation of a β‐CD/bisphenol A (BPA) inclusion complex with aromatic dihalides. Two dihalides, with and without a side chain, were used. This polycondensation results in a polyrotaxane (or pseudopolyrotaxane for polymers without stoppers) with a 1:1 threading ratio when the side chain is present and 2:3 when there is none. The long side chain prevents dethreading of the macrocycles. The best yield and a good threading ratio were obtained when the polycondensation was performed by liquid?solid phase transfer catalysis without solvent (L/S PTC) using 2,5‐bi(iodomethyl)‐4‐methoxy‐(1‐octyloxy)benzene as dihalide. The 1H NMR and FTIR spectra show that the products consist of β‐CD and polyether. The 2D NOESY NMR spectrum shows that the polyether chains are included in the β‐CD cavity. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4391–4399, 2009 相似文献
8.
Saïf Eddine Chrif Avisek Ghosh Saloua Chelli Isabelle M. Dixon Jamil Kraiem Sami Lakhdar 《Chemical science》2022,13(41):12065
Olefin cross-metathesis is a cornerstone reaction in organic synthesis where stereoselectivity is typically governed by the structure of the catalyst. In this work, we show that merging Grubbs second generation catalyst, a classical E-selective catalyst, with a readily available photocatalyst, enables the exclusive formation of the contra-thermodynamic Z-isomer. The scope and limitations of this unprecedented approach are discussed based on both computational and experimental mechanistic data. Light is magic! The combination of Grubbs second generation catalyst, a well-known catalyst for E-selective olefin metathesis, with a photosensitizer enables efficient access to the contra-thermodynamic Z-isomers. 相似文献
9.
Saloua Chatti 《Logica Universalis》2011,5(2):225-247
Referential opacity is the failure of substitutivity of identity (SI, for short) and in Quine’s view of existential generalization
(EG, for short) as well. Quine thinks that its “solution” in epistemic and doxastic contexts, which relies on the notion of
exportation, leads to undesirable results. But epistemic logicians such as Jaakko Hintikka and Wolfgang Lenzen provide another
solution based on a different diagnosis: opacity is not, as in Quine’s view, due to the absence of reference, it is rather due to the plurality of references; therefore, one must stabilize the reference to restore SI and EG. However, Hintikka’s semantics remains classical
in its treatment of existence, which makes EG non-applicable to possible objects, while in Lenzen’s system, EG is applicable
by means of a particular quantifier. But this requires adding the predicate of existence to account for real objects. In this
paper, I will show the advantages and disadvantages of both solutions and will end by providing an alternative approach to
the problem of non-existent objects, which stays into the frame of possible worlds semantics, but introduces some more restrictions,
eliminates the problematic predicate of existence, and applies a neutral quantifier to possible non-existent objects. 相似文献
10.
El Abbari Hafsa Bentahar Sarah El Marouani Maryam Taibi Mhamed Zeriouh Abdelouahab Sebbahi Saloua Kifani-Sahban Fatima 《Journal of Thermal Analysis and Calorimetry》2019,137(5):1485-1492
Journal of Thermal Analysis and Calorimetry - In this work, the physicochemical and thermomechanical characteristics of date seeds were examined during their pyrolysis under inert atmosphere from... 相似文献