25 research outputs found
Transverse magnetic mode nonreciprocal propagation in an amplifying AlGaInAs/InP optical waveguide isolator.
International audienceThe design, fabrication, and characterization of an amplifying transverse magnetic ÍTMÍ-mode optical waveguide isolator operating at a wavelength of 1300 nm are presented. The magneto-optical Kerr effect induces nonreciprocal modal absorption in a semiconductor optical amplifier with a laterally magnetized ferromagnetic metal contact. Current injection in the active structure compensates for the loss in the forward propagation direction. Monolithic integration of this optical isolator configuration with active InP-based photonic devices is straightforward. The combination of AlGaInAs/ InP active material and the metal alloy Co 50 Fe 50 results in greatly improved performance. 99 dB/ cm TM mode isolation and significantly reduced insertion loss are demonstrated
Transverse magnetic mode nonreciprocal propagation in an amplifying AlGaInAsâInP optical waveguide isolator
De selektiviteit van metaalgedopeerde silicagelfazen in de liganduitwisselingschromatografie
Les pratiques enseignantes intĂ©grant le numĂ©rique :les logiques professionnelles, les attentes didactiques et sociales. Ătude de cas de dix pratiques enseignantes genevoises aux prises avec le numĂ©rique
A partir dâune enquĂȘte de terrain basĂ©e sur des entretiens semi-directifs rĂ©alisĂ©s avec dix enseignants genevois, ce travail de recherche explore la question des pratiques enseignantes avec lâusage du numĂ©rique dans les classes dâĂ©cole primaire. Lâobjectif de cette recherche est de mieux comprendre le travail enseignant aux prises avec le numĂ©rique en prenant en compte les spĂ©cificitĂ©s des disciplines scolaires, les situations dâapprentissages quotidiennes, les formations suivies par les enseignants et le contexte de la crise sanitaire du covid-19. Nous verrons comment les pratiques enseignantes incluent le numĂ©rique Ă partir des logiques professionnelles, didactiques et sociales. A travers cette analyse, nous aurons un aperçu des expĂ©riences individuelles des enseignants genevois avec le numĂ©rique. Cet aperçu sera analysĂ© et permettra de comprendre ce quâils dĂ©crivent, ce quâils expĂ©rimentent, ce quâils aimeraient faire, et ce quâils ne peuvent pas faire.</p
Quantitative analysis of hops and hop extracts by high pressure ion exchange chromatography
A new analysis for hop acids in hops and hop extracts is described. It is based on recent developments in high pressure liquid chromatography using pellicular anion exchange column filling material. Quantitative evaluation of α-acids, ÎČ-acids and oxidation products in hops and hop extracts is carried out by standard addition of pure humulone. The α-acids are completely separated from other hop substances before quantitation. The results of α-acids determinations must therefore be more accurate than was formerly possible and they are compared with conductometric titration results which are systematically higher.
This is to be expected as it becomes more and more obvious that paper strip and conductometric analysis are not selective enough and determine fractions as âα-acidsâ which are in fact oxidation products of the hop acids