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1.
This article allows the determination of the induced perturbations at the ends of the coaxial line in wide frequency band enough. The perturbation source is a current direct point injection into the cable screen in any position. For this, we have applied the theory of the state variables, with foundation of the quasi-TEM approximation, in order to simulate the coaxial line above a ground level that has a finished conductivity. This allows us to supply the current and voltage expressions at the ends of the line as their analytic forms for any conditions of charge. Next, the elaborate objective is to verify experimentally on concrete applications if the test obtained results confirm the theoretical expectations supplied by calculation code finalizing. 相似文献
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Well-known as a hazardous compound, nitrite constitute a real threat to the public health. So, there is a pressing need to detect and quantify them in different matrix. Even though conventional analytical methods can be used to address this issue, electrochemistry allows a fast, sensitive, and efficient analysis. Conducting polymers continue to raise great interest among scientific communities due to their properties. Moreover, their combination with carbon nanomaterials, or metallic nanoparticles improves their properties, and provides great results. In this paper, we will focus on some revealing works devoted to the electrochemical detection of nitrite using this kind of materials. 相似文献
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Oularbi Larbi Turmine Mireille El Rhazi Mama 《Journal of Solid State Electrochemistry》2017,21(11):3289-3300
Journal of Solid State Electrochemistry - In this paper, a new nanocomposite of polypyrrole (PPy) and carbon nanofibers (CNFs)-modified carbon paste electrode (CPE) has been reported for the... 相似文献
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Aziz Bouymajane Yassine Oulad El Majdoub Francesco Cacciola Marina Russo Fabio Salafia Alessandra Trozzi Fouzia Rhazi Filali Paola Dugo Luigi Mondello 《Molecules (Basel, Switzerland)》2020,25(22)
Olive oil is an important product in the Mediterranean diet, due to its health benefits and sensorial characteristics. Picholine marocaine is the most cultivated variety in Morocco. The present research aims to evaluate the phenolic compounds, vitamin E and fatty acids of commercial Picholine marocaine virgin olive oils (VOOs) from five different North Moroccan provinces (Chefchaouen, Taounate, Errachidia, Beni Mellal and Taza), using HPLC-photodiode array (PDA)/electrospray ionization (ESI)-MS, normal phase (NP)-HPLC/ fluorescence detector (FLD) and GC-flame ionization detector (FID)/MS, respectively. The obtained results showed an average content of 130.0 mg kg−1 of secoiridoids (oleuropein aglycone, 10-hydroxy-oleuropein aglycone and ligstroside aglycone, oleocanthal and oleacein), 108.1 mg kg−1 of phenolic alcohols (tyrosol and hydroxytyrosol), 34.7 mg kg−1 of phenolic acids (caffeic acid, ferulic acid and elenolic acid), and 8.24 mg kg−1 of flavonoids (luteolin, luteolin glucoside, apigenin). With regard to vitamin E, α-tocopherol was the most abundant vitamin E (57.9 mg kg−1), followed by α-tocotrienol (2.5 mg kg−1), γ-tocopherol (4.5 mg kg−1) and β-tocopherol (1.9 mg kg−1), while δ-tocopherol was not detected. Moreover, 14 fatty acids were found and, among them, oleic acid (76.1%), linoleic acid (8.1%) palmitic acid (8.7%) and stearic acid (2.5%) were the major fatty acids detected. Finally, heat map and principal component analysis allowed us to classify the studied provinces in terms of VOO chemical composition: Chefchaouen (tyrosol and hydroxytyrosol), Taounate (oleuropein aglycone), Errachidia (ferulic acid, w-3 and w-6), Beni Mellal (oleocanthal) and Taza (luteolin and oleic acid). 相似文献
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Structural Chemistry - Experimental and computational studies were performed to determine the antioxidant activities of harmine, harmaline, harmalol, harmane, and... 相似文献
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Sanaâ Majid Mamia El Rhazi Aziz Amine Antonella Curulli Giuseppe Palleschi 《Mikrochimica acta》2003,143(2-3):195-204
Carbon paste electrodes modified with conducting polymers for sensitive and selective determination of lead are presented. A novel method for generating a reproducible polymer-coated electrode surface is developed. We prove that 1,8-diaminonaphthalene (1,8-DAN) mixed with a carbon paste electrode leads to a conducting polymer in acidic medium while, in the same medium, this polymer is known to be non-conducting on platinum electrode. The electrode behaviour of poly(1,8-DAN), electropolymerised into carbon paste, was investigated by cyclic voltammetry in the presence of the ferri-ferrocyanide couple.A carbon paste electrode modified with poly(1,8-DAN) was used to determine Pb2+ in aqueous solutions. Pb2+ ions were firstly complexed and then electrochemically deposited by a potential step to –0.9V. The accumulated lead after reduction was anodically stripped by differential pulse voltammetry. Different parameters, such as pH of the solution, preconcentration time, and electropolymerisation procedures were studied.For a preconcentration time of ten minutes, the calibration graph was linear from 40 to 2070ngmL–1 with r2=0.998. The detection limit was found to be 30ngmL–1, and the relative standard deviation was 6%. 相似文献
8.
Salah Bouhroum Joseph A. Grondin Stephan Houdier Hassan Lazrek Mohamed Rhazi Abdelouahad Tolaimate 《Journal of carbohydrate chemistry》2013,32(3):309-314
ABSTRACT Hydrazine acetate is shown to effect selective deacetylation on peracetylated glycals like D-xylal, D-glucal, D-galactal and L-rhamnal. It is demonstrated that the observed selectivity on the -4 position cannot be explained by acetyl migration during the reaction. 相似文献
9.
Kaoutar Senhaji Rhazi Mohamed Najmouddine Jean Hoeffelman Lamine Abdellah 《电信纪事》2005,60(3-4):454-471
With reference to a preceding paper, this paper allows, in a first step, to determine, at low and high frequencies, approached expressions of the induced common mode voltages at the extremities of a shielded line influenced by a punctual current injection along the shield. These expressions are established for the case of a helicoidal screen with four different schemes of earth connections at the extremities. In a second step, the correction function, i.e. the ratio between the exact and approached solution, and the limit of validity of this latter at high frequencies are addressed. 相似文献
10.
The determination of mercury(II) ions at the trace level by inhibition of the invertase enzyme-catalysed hydrolysis of sucrose into glucose and fructose coupled to electrochemical batch injection analysis was investigated using two approaches. In the first, the glucose produced was detected by injection of 100 microliters samples into the batch injection cell containing a platinum electrode modified by immobilised glucose oxidase. In the second, the glucose and fructose present in injected samples were oxidised directly at a copper-modified glassy carbon electrode. The experimental parameters were optimised and the degree of enzyme inhibition by mercury(II) ions under both conditions was measured. Mercury concentrations in the ng ml-1 range were determined by these two techniques with low sample and reagent consumption. Comparison is made between the two methods and perspectives as a screening test for field application are indicated. 相似文献