The Schatten–von Neumann class associated with the Gabor–Riemann–Liouville operator

Periodica Mathematica Hungarica - In this paper, we define the localization operator associated with the Riemann–Liouville operator, and show that it is not only bounded, but it is also in...     

Regenerative,low-cost and switchable photoelectrochemical sensor for detection of Cu2+ using MnO2-GO heterojunction

Journal of Solid State Electrochemistry - In this work, we investigate the properties of manganese dioxide (MnO2) and graphene oxide (GO) to develop a new photoelectrochemical (PEC) sensor-based...     

A generalization of Fan��s matching theorem

We introduce a generalized coercivity type condition for setvalued maps defined on topological spaces endowed with a generalized convex structure and we extend Fan’s matching theorem.     

1,3,4‐Thiadiazole, 1,3,4‐thiadiazine, 1,3,6‐thiadiazepane and quinoxaline derivatives from symmetrical hydrazine‐1,2‐dicarbothioamide as well as N,N″‐ethane‐1,2‐diylbis(thiourea) derivatives

Reactions of N,N′‐disubstituted hydrazine‐1,2‐carbothioamides 8a‐c and substituted N,N″‐ethane‐1,2‐diylbis(thioureas) 9a‐c with 2,3,5,6‐tetrachloro‐1,4‐benzoquinone (chloranil, 10a ) and 2,3,5,6‐tetrabromo‐1,4‐benzoquinone (bromanil, 10b ) to form N,N′‐disubstituted 1,3,4‐thiadiazole‐2,5‐diamines 11a‐c , substituted 3‐amino‐6,7‐dichloro‐2,3‐dihydro‐1H‐4,2,1‐benzothiadiazine‐5,8‐diones 12a‐c , 2,3,7,8‐tetrahalothianthrene‐1,4,6,9‐tetrones 13a,b , substituted 5,6,8‐trihalo‐7‐oxo‐3,7‐dihydroquinoxaline‐2H‐carbothioamides 14a‐c, 15a‐c and 7‐substituted imino‐1,3,6‐thiadiazepane‐2‐thiones 16a‐c are reported.     

Action des hydrazines fluoroalkylées sur les phosphoallènes: synthèse d’hydrazones N-fluoroalkylées β-phosphonatées

Ten phosphorylated β-hydrazones of structure R₂P(O)C(NNHR_F)CHR₂′ were prepared in 54-91% yield by heating the allenes R₂P(O)CHCCR₂′ with fluorinated hydrazines H₂NNHR_F in chloroform or methanol [R=Ph, OCH₂C(Me)₂CH₂O or OCH₂C(Me)(Pr)CH₂O, R′=H or Me and R_F=CH₂CF₃ or C₆F₅]. Two cyclohexyl derivatives were prepared similarly from R₂P(O)CHCCy. The triphenyl derivatives Ph₂P(O)CH₂C(NNHCH₂CF₃)Ph and Ph₂P(O)CH₂C(NNHC₆F₅)Ph were made in 91 and 68% yield by heating the ketones Ph₂P(O)CH₂C(O)Ph with an ethanol solution of the corresponding hydrazines. The stereochemistry of the hydrazones was determined by multinuclear NMR experiments. Compounds with C(NNHR_F)Me groups exist as a mixture of Z and E isomers, with the Z form predominating (fluorinated group syn to phosphorus). Those with C(NNHR_F)CHMe₂, C(NNHR_F)Cy or C(NNHR_F)Ph groups were formed selectively, the Z isomers being the only products. The results are explained by steric hindrance, the bulkier isopropyl, cyclohexyl or phenyl group disfavouring the E configuration. , , , NMR data, coupling constants and IR data are reported.     

Modification and generalization of some methods to improve the accuracy of α-determination in the 1/E1+α epithermal neutron spectrum

Some methods described in the literature for the determination of α in the 1/E^1+α epithermal neutron spectrum are critically reviewed with respect to their accuracy. The multi resonance—detector method with Cd-covered irradiations, as used by SCHUMANN and ALBERT, is generalized by subtracting the epithermal 1/v-tail and by introducing the effective resonance energy, as defined by RYVES. The two-detector method of RYVES is modified by using Cd-ratio measurements, thus eliminating the introduction of systematic errors due to the inaccuracy of absolute nuclear data. The adapted methods are applied in channel 15 of the Thetis reactor (Gent). Research Associate of the “Nationaal Fonds voor Wetenschappelijk Onderzoek”     

Wigner Measures Approach to the Classical Limit of the Nelson Model: Convergence of Dynamics and Ground State Energy

We consider the classical limit of the Nelson model, a system of stable nucleons interacting with a meson field. We prove convergence of the quantum dynamics towards the evolution of the coupled Klein–Gordon–Schrödinger equation. Also, we show that the ground state energy level of \(N\) nucleons, when \(N\) is large and the meson field approaches its classical value, is given by the infimum of the classical energy functional at a fixed density of particles. Our study relies on a recently elaborated approach for mean field theory and uses Wigner measures.     

A scenario-based stochastic model for supplier selection in global context with multiple buyers,currency fluctuation uncertainties,and price discounts

Suppliers network in the global context under price discounts and uncertain fluctuations of currency exchange rates have become critical in today’s world economy. We study the problem of suppliers’ selection in the presence of uncertain fluctuations of currency exchange rates and price discounts. We specifically consider a buyer with multiple sites sourcing a product from heterogeneous suppliers and address both the supplier selection and purchased quantity decision. Suppliers are located worldwide and pricing is offered in suppliers’ local currencies. Exchange rates from the local currencies of suppliers to the standard currency of the buyer are subject to uncertain fluctuations overtime. In addition, suppliers offer discounts as a function of the total quantity bought by the different customer’ sites over the time horizon irrespective of the quantity purchased by each site.     

Development of dry derivatization and headspace solid-phase microextraction technique for the GC-ECD determination of haloacetic acids in tap water

A simple, fast and efficient liquid-liquid extraction (LLE) technique using headspace solid-phase microextraction (HS-SPME), in conjunction with gas chromatography-electron capture detection (GC-ECD) has been developed for the determination of haloacetic acids (HAAs) in tap water. The analytical procedure involves LLE, evaporation of extraction solvent to dryness, derivatization of HAAs into their methyl esters with acidic methanol, HS-SPME using 100-μm polydimethylsiloxane (PDMS) fiber, and GC-ECD determination. The derivatization process was optimized in dry conditions to achieve maximum sensitivity using the following conditions: esterification for 10 min at 55°C in 50 μL methanol, 30 μL sulphuric acid and 0.1 g anhydrous sodium sulphate. The HS-SPME conditions were also optimized and good sensitivity was obtained at a sampling temperature of 25°C, an absorption time of 10 min and a desorption time of 2 min. The linear calibration curves were observed for the concentration ranging from 0.1 to 200 μg/L with the correlation coefficients (R ²) greater than 0.993 and the relative standard deviation (RSD) less than 12%. The method detection limits of all analytes ranging from 0.02 to 0.7 μg/L were obtained. The proposed method is compared directly to standard EPA method 552.2 in drinking water, and significant advantage in terms of selectivity was observed. Finally the optimized procedure was applied to the analysis of HAAs in Bizerte drinking water. The studied HAA were detected in all the water samples and the concentration of total HAA5 ranged from 17.8 to 70.3 μg/L.