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101.
Dr. Li Di Prof. Per Artursson Dr. Alex Avdeef Prof. Leslie Z. Benet Prof. J. Brian Houston Dr. Manfred Kansy Edward H. Kerns Prof. Hans Lennernäs Dr. Dennis A. Smith Prof. Kiyohiko Sugano 《ChemMedChem》2020,15(20):1862-1874
Passive permeability is a key property in drug disposition and delivery. It is critical for gastrointestinal absorption, brain penetration, renal reabsorption, defining clearance mechanisms and drug-drug interactions. Passive diffusion rate is translatable across tissues and animal species, while the extent of absorption is dependent on drug properties, as well as in vivo physiology/pathophysiology. Design principles have been developed to guide medicinal chemistry to enhance absorption, which combine the balance of aqueous solubility, permeability and the sometimes unfavorable compound characteristic demanded by the target. Permeability assays have been implemented that enable rapid development of structure-permeability relationships for absorption improvement. Future advances in assay development to reduce nonspecific binding and improve mass balance will enable more accurately measurement of passive permeability. Design principles that integrate potency, selectivity, passive permeability and other ADMET properties facilitate rapid advancement of successful drug candidates to patients. 相似文献
102.
103.
《Journal of the European Ceramic Society》2020,40(6):2338-2344
The high-temperature and high-performance piezoelectric ceramics are required urgently in the petrochemical, automotive, and aerospace industries. In this work, the (0.85-x)BiFeO3-xPbTiO3-0.15BaTiO3 (BF-PT-BT, x = 0.21, 0.22, 0.23, 0.24 and 0.25) piezoelectric ceramics with both high Curie temperature and large piezoelectric constant d33 were presented. X-ray diffraction analysis shows that BF-PT-BT ceramics exhibit dominant perovskite structure with the coexistence of tetragonal (T) and rhombohedral (R) phases. The c/a ratio, Curie temperature, piezoelectric constant, dielectric constant and loss of the BF-PT-BT ceramics for x = 0.23 are 1.06, 546 °C, 222 pC/N, 545 and 0.013, respectively. Room temperature piezoelectric constant of BF-PT-BT ceramics is much higher than those of PbTiO3, PbNb2O6 and other ABO3 perovskite compounds (BaZrO3, Bi(Zn, Ti)O3, PbZrO3 and Pb(Mg, Nb)O3) modified ternary BiFeO3-PbTiO3 ceramics with similar Curie temperatures. The piezoelectric constant is almost unchanged after BF-PT-BT ceramics was annealed at 450 °C for 30 min, which is due to the stable switched non-180° domain and transformed R phase by annealing treatment. 相似文献
104.
《Ceramics International》2020,46(14):22438-22451
In this paper, two coating techniques, the high velocity oxy-fuel (HVOF) and air plasma spray (APS) techniques, were used to deposit a bond coat of NiCoCrAlYTa on the Inconel 625 substrate, followed by applying a topcoat of yttria-stabilized zirconia (YSZ). The samples were preoxidized in an argon-controlled furnace at a temperature of 1000 °C for 12 and 24 h to characterize the microstructure of a thermally grown oxide (TGO) using the two coating techniques. The most suitable preoxidized samples were further tested for isothermal oxidation at 1000 °C for up to 120 h, and a hot corrosion test was performed at 1000 °C for up to 52 h or until spalling occurred. As-sprayed and oxidized samples prepared with different coating techniques were evaluated in terms of their microstructure using different characterization methods, such as field emission scanning electron microscopy (FESEM), variable pressure scanning electron microscopy (VPSEM), energy dispersive X-ray spectroscopy (EDS) equipped with energy dispersive X-ray and X-ray diffraction (XRD) analyses. In addition, the mechanical properties of these samples were evaluated using adhesion tests. The results show that the YSZ/NiCoCrAlYTa coating applied with the HVOF technique forms a more thin and continuous layer of TGO than that obtained when applying a YSZ/NiCoCrAlYTa coating using the APS technique, indicating that a severe brittle oxidation interface exists between the two layers. The results also indicate that the mechanical strength obtained from the adhesion test of the coated samples is observably affected by the oxidation behaviors obtained with the different deposition techniques chosen. 相似文献
105.
106.
《Journal of the European Ceramic Society》2020,40(8):3122-3128
Lanthanum zirconate is a promising thermal barrier coating material owing to its excellent thermophysical properties and La plays the key role in its corrosion resistance. Here, an amorphous precursor is used as raw feedstock material so as to synthesize lanthanum zirconate coatings with tailorable composition by atmospheric plasma spray (APS). Three lanthanum zirconate coatings of La1.7Zr2.3O7.15, La2.0Zr2.0O7.0 and La2.3Zr1.7O6.85 are fabricated. Furthermore, the corrosion resistance of the as-sprayed coatings against CaO-MgO-Al2O3-SiO2 at 1250℃ is investigated. The increased La content promotes the formation of a sealing layer of the crystalline Ca2La8(SiO4)6O2 apatite, which slows down the penetration of molten CaO-MgO-Al2O3-SiO2. Therefore, the infiltration rate of the La2.3Zr1.7O6.85 coating decreased up to 42.6 % compared with the other two coatings. This work develops a feasible preparation strategy to control the La composition for the improved corrosion resistance, which is expected to guide the future coating design and synthesis for the materials with big composition changes during the APS process. 相似文献
107.
《Journal of the European Ceramic Society》2020,40(4):1513-1521
Prediction of surface cracking in ceramics due to quenching is performed numerically using either the coupled criterion or a cohesive zone model. Under such a thermal shock, a network of short cracks with minimal spacing between them initiate and propagate until some of them stop while the others continue propagating. The numerical implementation consists of a periodic array of cracks modeled by a representative volume element. It allows crack initiation, simultaneous propagation and period doubling to be predicted. The investigation of the crack period doubling allows a precise determination of the optimal crack spacing, which decreases with an increasing thermal shock amplitude. The predicted crack spacing results are in agreement with experimental measurements. 相似文献
108.
《Journal of the European Ceramic Society》2020,40(14):4939-4948
We report on an unusual failure pattern resulting from thermally driven fracture of laser amplifier single crystals. The pattern led to some confusion with regard to the point of initiation due to the coalescence of hackle lines to a region within the fracture surface, rather than the more common divergence of hackle away from the origin. The pattern leads to new fracture terms: Hackle node - the coalescence of hackle marks to a point of prior compression. The feature is produced as a thermally-generated, centrally-located compressive region transforms to tension thereby drawing crack propagation and hackle to the compressive region, forming an internal terminus. Hackle terminus – a hackle node formed by final crack propagation within the component. As part of the analysis, the fracture toughness and slow crack growth constants of neodymium doped, yttrium ortho-vanadate (Nd:YVO4) were measured. Nd:YVO4 exhibits slow crack growth and is very brittle with a fracture toughness of only 0.48 MPa√m. 相似文献
109.
110.