RESUMEN
The luminescent and proton conductive Pt(ii) complex [PtCl(tpy-o-py)]Cl and its HCl adduct [PtCl(tpy-o-pyH)]Cl2 (o-Pt and o-Pt·HCl, respectively; tpy-o-py = 2,2':6',2''-terpyridine-6',2'''-pyridine) were synthesised and their crystal structures, vapochromic behaviour, and proton conduction, were investigated and compared to those of the para isomers [PtCl(tpy-p-py)]Cl and [PtCl(tpy-p-pyH)]Cl2 (p-Pt and p-Pt·HCl, respectively; tpy-p-py = 2,2':6',2''-terpyridine-4',4'''-pyridine). X-ray structure analysis revealed that the intermolecular metallophilic (PtPt) interaction was negligible in o-Pt but effective in o-Pt·HCl. Reversible transformation between o-Pt and o-Pt·HCl coupled with significant colour and luminescence changes was achieved by four different external stimuli, namely: exposure of o-Pt to humid HCl gas to form o-Pt·HCl, heating, exposure to MeOH vapour, and finally drying in air to regenerate the original o-Pt. The intraligand π-π* orange emission observed for o-Pt exhibited negligible dependence on the relative humidity (RH). Conversely, o-Pt·HCl exhibited red metal-metal-to-ligand charge-transfer (MMLCT) phosphorescence at 725 nm, originating from effective intermolecular Pt-Pt interactions, and interesting vapochromic behaviour that was dependent on the RH. Notably, o-Pt·HCl presented higher conductivity than the p-Pt·HCl isomer at RH < 80%. This trend was reversed at RH values > 80%, probably owing to the second water-adsorption-induced transformation of p-Pt·HCl. The cooperative phenomenon between the proton conduction and vapochromic behaviour observed for both o-Pt·HCl and p-Pt·HCl should allow the visualisation of the proton-conducting pathway, without the need for a bulk electrode, via the absorption and emission colours at both macroscopic and microscopic levels.
RESUMEN
We have probed the crystalline electric-field ground states of pure |J=7/2,J_{z}=±5/2⟩ as well as the anisotropic c-f hybridization in both valence fluctuating systems α- and ß-YbAlB_{4} by linear polarization dependence of angle-resolved core level photoemission spectroscopy. Interestingly, the small but distinct difference between α- and ß-YbAlB_{4} was found in the polar angle dependence of linear dichroism, indicating the difference in the anisotropy of c-f hybridization, which may be a key to understanding a heavy Fermi liquid state in α-YbAlB_{4} and a quantum critical state in ß-YbAlB_{4}.
RESUMEN
An angle-resolved linearly polarized hard X-ray photoemission spectroscopy (HAXPES) system has been developed to study the ground-state symmetry of strongly correlated materials. The linear polarization of the incoming X-ray beam is switched by a transmission-type phase retarder composed of two diamond (100) crystals. The best value of the degree of linear polarization was found to be -0.96, containing a vertical polarization component of 98%. A newly developed low-temperature two-axis manipulator enables easy polar and azimuthal rotations to select the detection direction of photoelectrons. The lowest temperature achieved was 9â K, offering the chance to access the ground state even for strongly correlated electron systems in cubic symmetry. A co-axial sample monitoring system with long-working-distance microscope enables the same region on the sample surface to be measured before and after rotation. Combining this sample monitoring system with a micro-focused X-ray beam by means of an ellipsoidal Kirkpatrick-Baez mirror (25â µm × 25â µm FWHM), polarized valence-band HAXPES has been performed on NiO for voltage application as resistive random access memory to demonstrate the micro-positioning technique and polarization switching.
RESUMEN
Currently, transnasal esophagogastroduodenoscopy using an ultrathin endoscope is being widely carried out as a screening test for early gastric cancer. We compared the diagnostic utility of ultrathin esophagogastroduodenoscopy with that of conventional esophagogastroduodenoscopy in detecting 42 lesions of early gastric cancer that had a diameter of Asunto(s)
Endoscopios
, Endoscopía del Sistema Digestivo
, Tamizaje Masivo/instrumentación
, Neoplasias Gástricas/diagnóstico
, Anciano
, Detección Precoz del Cáncer
, Femenino
, Humanos
, Masculino
, Persona de Mediana Edad