ABSTRACT
High-temperature scintillation detectors play a significant role in oil exploration. However, traditional scintillators have limited ability to meet the requirements of practical applications owing to their low thermal stability. In this study, we designed and developed a one-dimensional (1D) Cs5Cu3Cl6I2 scintillator with high thermal stability. In addition, by preparing Cs5Cu3Cl7I, we proved that the Cs5Cu3Cl6I2 scintillator exhibits high thermal stability because the bridges linking the structural units in the 1D chain structure are only formed by I- ions, which improve their structural rigidity. The scintillator has a high steady-state light yield (59,700 photons MeV-1) and exhibits the highest spatial resolution for powder-based scintillation screens (18 lp mm-1) after cyclic treatment within the temperature range of 298-423 K. The Cs5Cu3Cl6I2 scintillator allows the visualization of alloy melting, indicating that it has significant potential for application in high-temperature environments. This study provides a new perspective toward the design of scintillators with high thermal stability.
ABSTRACT
X-rays play an extremely significant role in medical diagnosis, safety testing, scientific research, and other practical applications. However, as the main sources of radioactive pollution, the hazard of X-rays to human health and the environment has been a major concern. Herein, the explored perovskite scintillator of Cs2Zr1-xPbxCl6 in this work exhibits an ultrahigh radioluminescence intensity owing to the enhanced X-ray absorption for the introduction of Pb2+ ions. The Cs2Zr1-xPbxCl6 crystals are demonstrated as efficient scintillators with a self-trapped exciton emission and extremely high steady-state light yield (â¼101,944 photons meV-1). This fascinating scintillator provides a convenient visual tool for X-ray detection even for an indoor lighting environment, reaching a low detection limit of â¼14.2 nGy·s-1, which is about 1/387 of the typical medical imaging dose (5.5 µGy·s-1). Moreover, X-ray imaging with a high resolution of 16.6 lp·mm-1 is achieved with the as-explored Cs2Zr1-xPbxCl6 scintillator film. Herein, the Cs2Zr1-xPbxCl6 scintillator provides a feasible strategy for X-ray monitoring in the field of biomedicine, high-energy physics, national security, and other applications.
ABSTRACT
A series of electron capture materials Sr3SiO5 : Eu2+, RE3+ (RE = Nd3+, Ho3+, La3+) were prepared by high temperature solid state method. The photo-stimulated luminescence (PSL) and long afterglow performance were evaluated. After excited by UV light, it showed a strong up-conversion photo-stimulated read-out response when stimulated by 980 nm laser, which is attributed to the existence of deep traps (438 K). This property was especially shown in Sr3 SiO5 : Eu2+, La3+ and Sr3SiO5 : EU2+, Ho3+. Subsequently, the trapping depth and carrier concentration were studied. In this way, we verified the cause of PSL. The calculation of parameters of trapping electron in the thermoluminescence spectrum is through the method of Chen's half width, getting the value of trapping depth under the temperature of 438 K, which contrasts to the energy of 980 nm laser radiation. At the same time, the afterglow performance after co-doping with rare earth ion was greatly improved. The afterglow time of Sr3 SiO5 : Eu2+ , La3+ is up to 12 hours. Research results show that the change in mixed trap structure is the primary cause of photo-stimulated and long persistent luminescence properties.
ABSTRACT
OBJECTIVE: To investigate the effect of distraction osteogenesis (DO) in the treatment of severe mandibular micrognathia with severe obstructive sleep apnea and hypopnea syndrome (OSAHS). METHODS: 19 cases of severe mandibular micrognathia with OSAHS were treated by DO. All the patients received PSG and MSCT examination before and after DO to evaluate the therapeutic effect and changes in the upper airway. RESULTS: According to the evaluation standard, 17 cases were cured and 2 cases improved markedly. The sagittal distance and area, transverse distance and area of the upper airway increased markedly after DO. The volume of upper airway increased from (15 572.03 +/- 3 370.11) mm3 to (21 182.69 +/- 4 533.15) mm3.The airway change happened mainly in velopharyngeal region and the lingopharyngeal region, but not in the laryngopharyngeal region. CONCLUSIONS: DO can treat severe mandibular micrognathia patients with OSAHS effectively by enlarging the volume of upper airway,especially in the velopharynx and glossopharyngeum region. The MSCT plays an effective and important role.
Subject(s)
Micrognathism/surgery , Osteogenesis, Distraction/methods , Sleep Apnea, Obstructive/surgery , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Male , Mandible/surgery , Micrognathism/complications , Sleep Apnea, Obstructive/complications , Young AdultABSTRACT
IN THE TITLE TRICHODERMIN COMPOUND (SYSTEMATIC NAME: 12,13-ep-oxy-trichothec-9-en-4ß-yl 4-fluoro-benzoate), C(22)H(25)FO(4), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show the different conformations, viz. chair and half-chair. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope unit and the three C and one O atoms of the six-membered chair is 68.67â (2)°; these two mean planes are nearly perpendicular to the ep-oxy ring with angles of 87.97â (2)and 88.14â (2)°, respectively.