Search results for "element"

First measurement of the |t|-dependence of coherent J/ψ photonuclear production

2021

The first measurement of the dependence on $|t|$, the square of the momentum transferred between the incoming and outgoing target nucleus, of coherent J/ψ photoproduction is presented. The data were measured with the ALICE detector in ultra-peripheral Pb-Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}} = 5.02$ TeV with the J/$\psi$ produced in the central rapidity region $|y| < 0.8$, which corresponds to the small Bjorken-$x$ range $(0.3 − 1.4) \times 10 ^{−3}$. The measured $|t|$-dependence is not described by computations based only on the Pb nuclear form factor, while the photonuclear cross section is better reproduced by models including shadowing according t…

Minimum detection limits and applications of proton and helium induced X-ray emission using transition-edge sensor array

2017

Abstract We have determined minimum detection limits, MDLs, for elements 14 ⩽ Z ⩽ 86 using a transition-edge sensor array, TES array, and as a comparison using an Amptek X-123SDD silicon drift detector, SDD. This was done using a 3 MeV proton beam and a 5.1 MeV helium beam. MDLs were determined for a thin film sample on top of C substrate, and for a bulk sample containing mostly Al. Due to the higher peak-to-background ratio, lower detection limits were obtainable using the TES array for most of the elements. However, for elements 30 ⩽ Z ⩽ 45 the performance of the TES array was not as good as the SDD performance. This is due to the limitations of the TES used at energies >10 keV. The great…

Reduction and catalytic behaviour of heterobimetallic copper–lanthanide oxides

2008

Abstract The reduction of the heterobimetallic copper–lanthanide oxides 2CuO·CeO2 and 3CuO·Ln2CuO4 (Ln = La, Pr, Nd) was studied by H2-TG/DTA and H2-TPR. All systems exhibit two main reduction steps accompanied by mass losses in the temperature range 20–1000 °C. The first step was attributed to CuO reduction, whereas the second step is due either to copper reduction in the Ln2CuO4 phase with the concomitant formation of Ln2O3 or to the surface reduction of CeO2. The products were characterized by XRD, SEM, EDX, and BET techniques and are better described as supported copper type materials. They were active for the mesityl oxide (4-methyl-2-penten-2-one) gas phase hydrogenation.

Asymmetric Synthesis of Fluorinated Isoindolinones through Palladium-Catalyzed Carbonylative Amination of Enantioenriched Benzylic Carbamates

2015

The asymmetric synthesis of fluorinated isoindolinones has been achieved by a palladium-catalyzed aminocarbonylation reaction of the corresponding -fluoroalkyl o-iodobenzylamines. A base-mediated anti -hydride elimination process was suggested to explain the partial erosion of the optical purity observed in some cases. This mechanistic rationale enabled the minimization of this partial racemization by fine-tuning the pK(a) of the base.

Organocatalytic approach to benzofused nitrogen-containing heterocycles: enantioselective total synthesis of (+)-angustureine.

2008

Alkylthio-tetrasubstituted μ-Nitrido Diiron Phthalocyanines: Spectroelectrochemistry, Electrical Properties, and Heterojunctions for Ammonia Sensing.

2020

Alkylthio-tetrasubstituted μ-nitrido diiron phthalocyanine complexes are synthesized with n-butyl, iso-butyl, tert-butyl, and n-hexadecyl alkyl moieties. For the first time, a spectroelectrochemical investigation of μ-nitrido diiron phthalocyanines is achieved at all the redox steps. The complexes are stable in all their redox states, unlike their unsubstituted analogues. The interest of the present complexes is to prepare sensing devices by a solution processing method. Films are characterized by electronic absorption and Raman spectroscopies. Electrical measurements on resistors show the highly resistive behavior of these complexes, whatever the chain length. However, when combined with t…

Pededzes upes vides kvalitātes novērtējums

2019

Maģistra darbā izvēlētā tēma ir ,,Pededzes upes vides kvalitātes novērtējums”. Maģistra darba mērķis ir izvērtēt Pededzes upes ekoloģisko kvalitāti, balstoties uz pieejamajiem valsts monitoringa datiem. Pētītas fizikāli ķīmisko parametru izmaiņas, bioloģiskie elementi. Tāpat analizēti hidromorfoloģisko faktoru iezīmes uz ekoloģisko kvalitāti upes augštecē. Veikta arī fizikāli ķīmisko un bioloģisko rādītāju novērtēšana atbilstoši Ministru Kabineta noteikumiem. Pētījumā izmantoti dati no Latvijas Vides, ģeoloģijas un meteoroloģijas centra virszemes ūdeņu novērojumu stacijām NS Pededze, augšpus Alūksnes un Pededze, grīva. Maģistra darbs sastāv no 60 lapaspusēm, kas ietver 27 attēlus, 13 tabula…

Higgs and flavour phenomenology at the LHC era

2017

El pasado julio de 2012 la última pieza que restaba por comprobar del Modelo Estándar (SM) -el bosón de Higgs- fue detectada por los dos grandes experimentos multipropósito del CERN a una energía de 125 GeV. El Modelo Estándar es el marco teórico en el que se describen tres, de las cuatro interacciones fundamentales conocidas, que rigen la dinámica de todas las partículas subatómicas conocidas y que han sido observadas experimentalmente. En él se integran, pero no unifican, la teoría electrodébil -que a su vez conjuga electromagnetismo e interacción débil- y la cromodinámica cuántica, asociada a la interacción nuclear fuerte. El contenido en partículas fundamentales se puede dividir en tres…

CLIL Implementation in Greece : Empirical Findings from 2006 to 2020

2023

Abstract Despite the increasing interest in CLIL in Greece over the past decade, Greek CLIL research is largely absent from international review studies. This systematic review focuses on primary and secondary education, and examines peer-reviewed empirical research on CLIL implementation in Greece from 2006 to 2020. A total of 33 items are reviewed using qualitative Content Analysis. Organized according to commonalities shared by their foci, the reviewed items highlight three main research areas of CLIL implementation in Greece: (1) CLIL project evaluation, (2) CLIL students’ development, and (3) CLIL teachers. The reviewed studies suggest that CLIL implementation in Greece tends to be qua…

Agrupaciones autónomas de personas ante el impuesto sobre el valor añadido

2021

This work carries out the delimitation of the exemption in the European V.A.T., of the benefits made to its members, by the autonomous groups of people, highlighting the distinctions made by the community case law, with particular attention to the subjective element of the exemption.