Search results for "Triplet"
showing 10 items of 159 documents
Phosphorescence emission and polarization of quinoline 3-carbonitrile
1993
Abstract The phosphorescence emission and excitation spectra and their polarization have been studied for quinoline 3-carbonitrile in methylcyclohexane and ethanol glasses at 77 K. From the results obtained in this molecule (τ=1.15 sec in ethanol, τ=1.04 sec in methylcyclohexane and out-of-plane polarization) it is concluded that the emission is orginated from a triplet state of 3 ππ * character. The two major spin-orbit coupling mechanisms through which the ππ * state of quinoline 3-carbonitrile acquires dipole-allowed character via nπ * states are: 1. In ethanol glass: 2. In methylcyclohexane glass:
Characterisation of beam focus quality in biomedical nuclear microscopy: A Fourier optics approach
2009
Abstract The central peak widths of the 2D-autocorrelation function have been investigated as a Figure of Merit (FoM) of focus quality in nuclear microscopy using a quadrupole triplet lens system. The beam focus could be reliably characterised for direct scanning transmission ion microscopy (direct-STIM) images obtained with fluences as small as 5.8 × 10 9 ions cm - 2 which colocalisation tests showed did not introduce significant beam-induced changes in the cells.
Flavored CP asymmetries for type II seesaw leptogenesis
2013
A novel contribution to the leptonic CP asymmetries in type II seesaw leptogenesis scenarios is obtained for the cases in which flavor effects are relevant for the dynamics of leptogenesis. In the so-called flavored leptogenesis regime, the interference between the tree-level amplitude of the scalar triplet decaying into two leptons and the one-loop wave function correction with leptons in the loop, leads to a new nonvanishing CP asymmetry contribution. The latter conserves total lepton number but violates lepton flavor. Cases in which this novel contribution may be dominant in the generation of the baryon asymmetry are briefly discussed.
Isospin-symmetry breaking in masses of ≃ Nuclei
2018
Effects of the isospin-symmetry breaking (ISB) beyond mean-field Coulomb terms are systematically studied in nuclear masses near the N=Z line. The Coulomb exchange contributions are calculated exactly. We use extended Skyrme energy density functionals (EDFs) with proton–neutron-mixed densities, to which we add new terms breaking the isospin symmetry. Two parameters associated with the new terms are determined by fitting mirror and triplet displacement energies (MDEs and TDEs) of isospin multiplets. The new EDFs reproduce MDEs for the T=12 doublets and T=1 triplets, and TDEs for the T=1 triplets. Relative strengths of the obtained isospin-symmetry-breaking terms are not consistent with the d…
A gas ionisation Direct-STIM detector for MeV ion microscopy
2015
Abstract Direct-Scanning Transmission Ion Microscopy (Direct-STIM) is a powerful technique that yields structural information in sub-cellular whole cell imaging. Usually, a Si p-i-n diode is used in Direct-STIM measurements as a detector. In order to overcome the detrimental effects of radiation damage which appears as a broadening in the energy resolution, we have developed a gas ionisation detector for use with a focused ion beam. The design is based on the ETH Frisch grid-less off-axis Geiger–Muller geometry. It is developed for use in a MeV ion microscope with a standard Oxford Microbeams triplet lens and scanning system. The design has a large available solid angle for other detectors …
Oxaliplatin, irinotecan, and fluorouracil/folinic acid in advanced gastric cancer: a multicenter phase II trial of the Southern Italy Cooperative Onc…
2009
Purpose: This phase II trial assessed the tolerability and efficacy of a triplet of oxaliplatin, irinotecan, and fluorouracil/folinic acid in advanced gastric cancer. Methods: Patients with unresectable or metastatic gastric cancer, unexposed to palliative chemotherapy, received oxaliplatin 85 mg/m 2 iv and irinotecan 150 mg/m2 iv on day 1, 6S-folinic acid 250 mg/m2 iv and fluorouracil 750 mg/m2 iv on day 2, every 2 weeks. Response rate (RR) was assessed after a minimum of four cycles, and treatment continued up to 12 cycles. Results: Sixty-three patients were treated, with a median of eight (range 1-12) cycles/patient. Two complete and 19 partial responses were registered (RR 33% [95% CI, …
The transfer of tin and germanium atoms from N-heterocyclic stannylenes and germylenes to diazadienes.
2005
New N-heterocyclic stannylenes and germylenes were synthesized by transamination of E[N(SiMe3)2] (E = Ge, Sn) with alpha-amino-aldimines or ethylidene-1,2-diamines and were characterized by spectroscopic methods and in the case of the germylene 10 g by X-ray diffraction. The reactions of several germylenes and stannylenes with diazadienes were studied by using dynamic NMR and computational methods. Experimental and theoretical studies confirmed that metathesis with exchange of the Group 14 atom is feasible for both stannylenes and germylenes, with exchange rates being generally higher for stannylenes. The metathesis of the diazadiene 3 b and the stannylene 1 b follows second-order kinetics …
Enhancing triplet superconductivity by the proximity to a singlet superconductor in oxide heterostructures
2016
We show how in principle a coherent coupling between two superconductors of opposite parity can be realized in a three-layer oxide heterostructure. Due to strong intraionic spin-orbit coupling in the middle layer, singlet Cooper pairs are converted into triplet ones and vice versa. This results in a large enhancement of the triplet superconductivity, persisting well above the native triplet critical temperature.
Chemical and photochemical properties of chloroharmine derivatives in aqueous solutions
2015
Thermal and photochemical stability (ΦR), room temperature UV-vis absorption and fluorescence spectra, fluorescence quantum yields (ΦF) and lifetimes (τF), quantum yields of hydrogen peroxide (ΦH2O2) and singlet oxygen (ΦΔ) production, and triplet lifetimes (τT) have been obtained for the neutral and protonated forms of 6-chloroharmine, 8-chloroharmine and 6,8-dichloroharmine, in aqueous media. When it was possible, the effect of pH and oxygen concentration was evaluated. The nature of electronic transitions of protonated and neutral species of the three investigated chloroharmines was established using Time-Dependent Density Functional Theory (TD-DFT) calculations. The impact of all the fo…
Bis-Sulfone- and Bis-Sulfoxide-Spirobifluorenes: Polar Acceptor Hosts with Tunable Solubilities for Blue-Phosphorescent Light-Emitting Devices
2016
Bis-sulfone- and bis-sulfoxide-spirobifluorenes are a promising class of high-triplet-energy electron-acceptor hosts for blue phosphorescent light-emitting devices. The molecular design and synthetic route are simple and facilitate tailoring of the solubilities of the host materials without lowering the high-energy triplet state. The syntheses and characterization (including single-crystal structures) of four electron-accepting hosts are reported; the trend in their reduction potentials is consistent with the electron-withdrawing nature of the sulfone or sulfoxide substituents. Emission maxima of 421–432 nm overlap with the MLCT absorption of the sky-blue emitter bis(4,6-difluorophenyl-pyri…