•Growth of large (1 in.) diameter boules of single crystal Cs2HfCl6 and Cs2HfCl4Br2.•Intrinsic scintillator crystals with simple cubic crystal structures.•Energy resolutions below 3.8% at 662 keV and ...good proportional responses to photon energies.
This paper reports on successful growth and performance evaluation of two large diameter Cs2HfCl6 (CHC) and Cs2HfCl4Br2 (CHCB), both recently developed scintillator crystals. The discovery of Cs2HfCl6 (CHC) as a scintillator has lately generated much interest in this material and its family, which belongs to the K2PtCl6 cubic crystal structure. CHC is an intrinsic scintillator that is non-hygroscopic (slightly deliquescent, i.e., slightly moisture sensitive but does not deteriorate much when left in air), has no self-radioactivity, provides excellent energy resolution, and has excellent non-proportionality. CHC has a moderate density of 3.9 g/cm3 and an effective atomic number of 58. Reported in this paper are transparent crack-free single crystal CHC and CHCB boules of one inch in diameter, both grown using the vertical Bridgman method. Samples retrieved from the boules, sized ∅23 mm × 30 mm and ∅23 mm × 26 mm, respectively, are characterized for their optical and scintillation properties. Energy resolutions of 3.5% and 3.7% (FWHM) at 662 keV, respectively, are reported. Light yields of 23,000 ph/MeV and 20,000 ph/MeV have been calculated for the large diameter CHC and CHCB crystals, respectively. Results comparable to previously reported results for smaller crystals have been obtained. Studies on decay time, non-proportionality, as well as detector characterization are also reported.
•Structure, electronic and magnetic properties of Mn2PtSn and Mn1.4PtSn are studied.•TDos and PDos of two systems are calculated based on DFT combined with the FP-LAPW.•Total magnetic moment and ...exchange interactions were calculated.•Magnetization, specific heat and magnetic entropy changes have been obtained by MCs.•RCP has been obtained for different values of magnetic fields and temperatures.
In this work, we have studied the structure, electronic and magnetic properties of Mn2PtSn and Mn1.4PtSn by using the ab initio calculations and Monte Carlo study. The ab initio calculations, based on the functional theory of density combined with the method of linear augmented plane waves at potential, are performed to investigate both electronic and magnetic properties of the two compounds. The total and partial densities of two systems have been calculated. Mn1.4PtSn, the first known Heusler tetragonal (Mn vacancy-induced) superstructure compound, opens a new direction of research for superstructure-related properties in a family containing multiple compounds. We have deduced the total magnetic moment of the two systems. We observe an anisotropic fractal magnetic pattern of zero-field closing domains above the spin-reorientation transition temperature, which transforms into a set of high-field bubble domains. Below the spin-reorientation transition temperature, the strong in-plane anisotropy as well as the zero-field fractal self-affinity is gradually lost, while the formation of high-field bubble domains remains robust. The magnetization, specific heat and magnetic entropy change have been obtained by using the Monte Carlo simulations. The relative cooling power has been obtained for different values of external magnetic field and temperatures.
•DFT and MCS are performed on magnetocaloric, electronic and thermoelectric of GdCrO3.•GdCrO3 has semiconductor character and antiferromagnetic behavior.•Presence of spin reorientation transition is ...also observed in GdCrO3.•Maximum of MEC and RCP increase with increasing the magnetic field in GdCrO3.•Optical and thermoelectric properties of this compound are also characterized.
Density functional theory and Monte Carlo simulation are performed on the magnetocaloric, electronic, optical, thermoelectric and magnetic properties of GdCrO3. The density of states diagrams is discussed. The values of the exchange energy calculated between the magnetic configurations Gd and Cr atoms was calculated. The GdCrO3 has semiconductor character and antiferromagnetic behavior. The dielectric function, absorption and reflectivity are also investigated. The thermoelectric response is evaluated by calculating electrical conductivity, thermal conductivity and seebeck coefficient (S) by using BoltzTraP code. The magnetic moment of Cr and Gd are calculated. The Néel temperature has been obtained. The presence of spin reorientation transition is also observed in this system. The maximum magnetic entropy change and relative cooling power are found to be respectively, 2.64 J.K−1.kg−1 and 25 J.kg−1 for h = 5 T.
•Tl-, Hf- and Zr-based scintillator crystals with high density and high light yield.•Intrinsic scintillator crystals with simple cubic crystal structures.•Energy resolutions below 3.8% at 662 keV and ...good proportional responses to photon energies.
The re-discovery of Cs2HfCl6 (CHC) as a scintillator has lately generated much interest in this material and its family, which belongs to the K2PtCl6 cubic crystal structure 1. CHC is an intrinsic scintillator that is non-hygroscopic, has no self-radioactivity, provides good energy resolution, and has good non-proportionality. In this paper we are reporting growth and scintillation properties of two new and Tl-, Hf- and Zr-based compounds of Tl2HfCl6 and Tl2ZrCl6, with physical densities of 5.1 g/cm3 and 4.5 g/cm3, respectively and effective atomic numbers (Zeff) of 71 and 69, respectively. Samples from successfully grown 16 mm diameter boules were cut, processed, and characterized for their scintillation and radiometric properties. Energy resolutions of 3.7% (FWHM) for THC and 3.4% for TZC (FWHM) at 662 keV are measured. Primary luminescence decay times of 1.1 μs and 2.3 μs, for Tl2HfCl6 and Tl2ZrCl6, respectively, as well as good proportionality for both materials have been observed.
•Systematic designing of InAs based MWIR pBin photodetectors.•High quality InAs based MWIR pBin photodetector material growth using LPE.•InAs based mesa-type MWIR pBin photodetectors fabrication and ...characterization.•InAs based MWIR pBin photodetectors with D* higher than 109 Jones at 300 K.
Herein, the designing principles of InAs based pBin mid-infrared (MWIR) photodetectors grown by liquid phase epitaxy (LPE) are presented based on the lattice mismatch. pBin MWIR detector structures with InAs, InAs0.94Sb0.06 and InAs0.89Sb0.11 absorbers were designed and grown by LPE, and then fabricated into mesa type detectors. Room temperature electrical performances of the three kinds of detectors were characterized. All three kinds of detectors achieved detectivities higher than 1 × 109 cm Hz1/2 W−1, and especially the detector with an InAs absorber further achieved a detectivity of 1.6 × 1010 cm Hz1/2 W−1 at 300 K, which is the highest ever reported, indicating good material qualities of the detectors.
A successful demonstration of applying integrated strengthening using Hall-Petch strengthening (grains size effect) and precipitation strengthening is shown in the fcc based high entropy alloy (HEA) ...Al0.3CoCrFeNi, leading to quantitative determinations of the Hall-Petch coefficients for both hardness and tensile yield strength, as well as the enhancements in the yield strength from two distinct types of ordered precipitates, L12 and B2. An excellent combination of yield strength (~490MPa), ultimate tensile strength (~850MPa), and ductility (~45% elongation) was achieved by optimizing and coupling both strengthening mechanisms, resulting from a refined grain size as well as both L12 and B2 ordered precipitates. This opens up new avenues for the future development of HEAs, with the appropriate balance of properties required for engineering applications.
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•Fcc based Al0.3CoCrFeNi HEA shows very high propensity to grain-boundary strengthening (Hall-Petch effect)•Al0.3CoCrFeNi can be further precipitation strengthened by two different types of ordered (L12 & B2) precipitates•Coupling Hall-Petch strengthening with precipitation strengthening via both L12 & B2 precipitates results in excellent strength-ductility combination
Hyperfibrinolysis is a systemic condition occurring in various clinical disorders such as trauma, liver cirrhosis, and leukemia. Apart from increased bleeding tendency, the pathophysiological ...consequences of hyperfibrinolysis remain largely unknown. Our aim was to develop an experimental model of hyperfibrinolysis and to study its effects on the homeostasis of the blood–brain barrier (BBB). We induced a sustained hyperfibrinolytic state in mice by hydrodynamic transfection of a plasmid encoding for tissue-type plasminogen activator (tPA). As revealed by near-infrared fluorescence imaging, hyperfibrinolytic mice presented a significant increase in BBB permeability. Using a set of deletion variants of tPA and pharmacological approaches, we demonstrated that this effect was independent of N-methyl-D-aspartate receptor, low-density lipoprotein–related protein, protease-activated receptor-1, or matrix metalloproteinases. In contrast, we provide evidence that hyperfibrinolysis-induced BBB leakage is dependent on plasmin-mediated generation of bradykinin and subsequent activation of bradykinin B2 receptors. Accordingly, this effect was prevented by icatibant, a clinically available B2 receptor antagonist. In agreement with these preclinical data, bradykinin generation was also observed in humans in a context of acute pharmacological hyperfibrinolysis. Altogether, these results suggest that B2 receptor blockade may be a promising strategy to prevent the deleterious effects of hyperfibrinolysis on the homeostasis of the BBB.
•Hydrodynamic transfection of plasmids encoding for plasminogen activators leads to a hyperfibrinolytic state in mice.•Hyperfibrinolysis increases BBB permeability via a plasmin- and bradykinin-dependent mechanism.
In development, tissue regeneration or certain diseases, angiogenic growth leads to the expansion of blood vessels and the lymphatic vasculature. This involves endothelial cell proliferation as well ...as angiogenic sprouting, in which a subset of cells, termed tip cells, acquires motile, invasive behaviour and extends filopodial protrusions. Although it is already appreciated that angiogenesis is triggered by tissue-derived signals, such as vascular endothelial growth factor (VEGF) family growth factors, the resulting signalling processes in endothelial cells are only partly understood. Here we show with genetic experiments in mouse and zebrafish that ephrin-B2, a transmembrane ligand for Eph receptor tyrosine kinases, promotes sprouting behaviour and motility in the angiogenic endothelium. We link this pro-angiogenic function to a crucial role of ephrin-B2 in the VEGF signalling pathway, which we have studied in detail for VEGFR3, the receptor for VEGF-C. In the absence of ephrin-B2, the internalization of VEGFR3 in cultured cells and mutant mice is defective, which compromises downstream signal transduction by the small GTPase Rac1, Akt and the mitogen-activated protein kinase Erk. Our results show that full VEGFR3 signalling is coupled to receptor internalization. Ephrin-B2 is a key regulator of this process and thereby controls angiogenic and lymphangiogenic growth.
•Pb2FeMoO6 grown in a bulk phase only via High Pressure/High Temperature synthesis.•Cation ordering on the B-site, leading to a long-range ferrimagnetic state at 275 K.•Asymmetric magnetoresistance ...never observed in B-disordered Pb2FeMoO6.•Strong correlation between the half-metallicity and cation ordering.
We investigate the electric properties of Pb2FeMoO6 (PFMO), a double perovskite that can be grown in a bulk pure phase only via High Pressure/High Temperature solid-state reaction. The as-obtained PFMO is characterized by a high degree of cationic ordering at the B site between Fe3+ and Mo5+ and a ferrimagnetic transition with TN around 275 K. A semi-metallic to half-metallic transition seems to occur when the ferrimagnetic order arises thanks to the localization of a minority fraction of electrons on the Mo site. In this thermal regime, the system displays asymmetric magneto-resistivity, with selective-polarized carriers promoted by intense negative magnetic fields applied across the Néel transition during the cooling ramp. This cation-ordering related feature vanishes when the Mo-O bond length stabilizes, indicating a strong connection between the magnetic and electrical properties of this compound.
•Review recent progress in PVT growth of AlN substrates.•Review AlN seeds growth with PVT, pros and cons for homogeneous growth.•Highlight latest advances in preparing high-quality, large-size AlN ...substrates.
SiC, GaN, diamond, and AlN known as wide band-gap semiconductors, integrate the advantages of microelectronics, optoelectronics, and power electronics. The ultra-wide bandgap semiconductor AlN crystal has a direct bandgap of 6.1 eV at room temperature. AlN has led to a burgeoning research interest in the fabrication of devices due to its outstanding structure and fascinating physiochemical (microelectronics, optoelectronics and power-electronics, etc.) properties. In this review, we summarize some recent advances in growing physical vapor transport AlN substrates. First, we introduce the primary seed growth of AlN using two disparate growth strategies: on heterogeneous substrate and spontaneous nucleation. We then elaborate on their advantages and disadvantages for subsequent homogeneous growth. Second, we highlight ultramodern advances that have been made in the preparation of high-quality and large-size AlN substrates, discuss the optical properties of AlN. In the end, the current challenges and new opportunities for PVT grown AlN substrates in improving the quality are also discussed.
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