Effects of Er3+ concentration on the structure and optical properties of the MgAl2O4/MgO/Sr3Al2O6/SrAl2O4 mixed phases prepared by the citrate sol gel method

Please read abstract in the article.http://iopscience.iop.org/journal/2053-1591hj2021Physic

Tracheal injury in a toddler

Penetrating neck injuries are uncommon in the paediatric population. The initial management of these patients can be challenging to the  emergency room physician, and the surgeon that performs the operative treatment. The nature of these injuries tends to be very complicated since, typically, the patient presents with either excessive bleeding or a compromised airway due to the damage of vital structures in the neck area such as the trachea and carotid-sheath, and lack of corresponding protection from the vertebral bone. Here, we report a traumatic case of a 2-year-old girl that was referred to our unit after surviving an attempted murder by a deranged family member that slit her throat with a saw-toothed knife. The patient sustained a near complete slit of her throat, which was repaired primarily with satisfactory postoperative results

Properties and thermo-switch behaviour of LDPE mixed with carbon black, zinc metal and paraffin wax

This paper reports on the presence of wax and radiation-induced crosslinking on the morphology, thermal and mechanical properties, as well as electrical conductivity and thermo-switch properties of LDPE containing different amounts of carbon black (CB) or carbon black plus zinc metal as filler. Although the filler was generally well dispersed in the polymer or polymer/wax blend, there were clear indications of the formation of conductive pathways. Different combinations of polymer, wax, CB and zinc filler and radiation induced crosslinking gave rise to different extents of crystallinity and/or chain immobilization, which had an influence on the mechanical and thermo-mechanical properties, and on the electrical conductivity and thermo-switch behaviour. Most importantly, the presence of wax, and CB and CB/Zn fillers, gave rise to increased electrical conductivity. The thermal expansion in the composites did not seem to play a significant role in obtaining larger values of the positive temperature coefficient of resistivity (PTC). We found that the presence of a small amount of paraffin wax significantly increased the PTC coefficients of the LDPE based conductive composites, and that γ-radiation induced crosslinking provided the thermomechanical stability of the amorphous regions in LDPE needed to obtain a high PTC intensity, which would provide a cheap material with good thermo-switch functionality, which is something not observed before

Properties and thermo-switch behaviour of LDPE mixed with carbon black, zinc metal and paraffin wax

This paper reports on the presence of wax and radiation-induced crosslinking on the morphology, thermal and mechanical properties, as well as electrical conductivity and thermo-switch properties of LDPE containing different amounts of carbon black (CB) or carbon black plus zinc metal as filler. Although the filler was generally well dispersed in the polymer or polymer/wax blend, there were clear indications of the formation of conductive pathways. Different combinations of polymer, wax, CB and zinc filler and radiation induced crosslinking gave rise to different extents of crystallinity and/or chain immobilization, which had an influence on the mechanical and thermo-mechanical properties, and on the electrical conductivity and thermo-switch behaviour. Most importantly, the presence of wax, and CB and CB/Zn fillers, gave rise to increased electrical conductivity. The thermal expansion in the composites did not seem to play a significant role in obtaining larger values of the positive temperature coefficient of resistivity (PTC). We found that the presence of a small amount of paraffin wax significantly increased the PTC coefficients of the LDPE based conductive composites, and that gamma-radiation induced crosslinking provided the thermo-mechanical stability of the amorphous regions in LDPE needed to obtain a high PTC intensity, which would provide a cheap material with good thermo-switch functionality, which is something not observed before

Structure and photoluminescent properties of green-emitting terbium-doped GdV1−xPxO4phosphor prepared by solution combustion method

Terbium-doped gadolinium orthovanadate (GdVO4:Tb3+), orthophosphate monohydrate (GdPO4•H2O:Tb3+)and orthovanadate–phosphate (GdV,PO4:Tb3+) powder phosphors were synthesized using a solution combustion method. X-Ray diffraction analysis confirmed the formation of crystalline GdVO4, GdPO4•H2OandGdV,PO4. Scanning electron microscopy images showed that the powder was composed of an agglomeration of particles of different shapes, ranging from spherical tooval to wire-like structures. The chemical elements present were confirmed by energy dispersive spectroscopy, and the stretching mode frequencies were determined by Fourier transform infrared spectroscopy. UV–visible spectroscopy spectra showed a strong absorption band with a maximum at 200nm assigned to the absorption of VO43-and minor excitation bands assigned to f→f transitions of Tb3+. Four characteristic emission peaks were observed at 491, 546, 588 and 623nm, and are attributed to 5D4 → 7Fj (j=6, 5, 4 and 3). The photoluminescent prominent green emission peak (5D4→7F5) was centred at 546nm.The structure and possible mechanism of light emission from GdV1xPxO4:% Tb3+are discussed.Terbium-doped gadolinium orthovanadate (GdVO4:Tb3+), orthophosphate monohydrate (GdPO4•H2O:Tb3+)and orthovanadate–phosphate (GdV,PO4:Tb3+) powder phosphors were synthesized using a solution combustion method. X-Ray diffraction analysis confirmed the formation of crystalline GdVO4, GdPO4•H2OandGdV,PO4. Scanning electron microscopy images showed that the powder was composed of an agglomeration of particles of different shapes, ranging from spherical tooval to wire-like structures. The chemical elements present were confirmed by energy dispersive spectroscopy, and the stretching mode frequencies were determined by Fourier transform infrared spectroscopy. UV–visible spectroscopy spectra showed a strong absorption band with a maximum at 200nm assigned to the absorption of VO43-and minor excitation bands assigned to f→f transitions of Tb3+. Four characteristic emission peaks were observed at 491, 546, 588 and 623nm, and are attributed to 5D4 → 7Fj (j=6, 5, 4 and 3). The photoluminescent prominent green emission peak (5D4→7F5) was centred at 546nm.The structure and possible mechanism of light emission from GdV1xPxO4:% Tb3+are discusse