Propylene is deemed as a kind of key raw materials with significant value in industrial production. Highly dispersed Zn species are served as active sites in catalyzing propane dehydrogenation reaction (PDH). More imp...
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Propylene is deemed as a kind of key raw materials with significant value in industrial production. Highly dispersed Zn species are served as active sites in catalyzing propane dehydrogenation reaction (PDH). More importantly, the morphology and textural properties of Si-based support exert the great influence on the formation of active Zn species. Herein, active Zn species were dispersed on macroporous commercial SiO2, mesoporous siliceous materials (SBA-15, MCF, DMSN, KIT-6), and microporous silicalite-1 (S-1), respectively. Characterization result indicated that the dispersed active ZnO species were prone to be formed on S-1, which could be attributed to the confinement effect of micropores in S-1 and the abundant Si-OH groups interacted with Zn2+ species. As a result, the optimal ZnOA/S-1 catalyst exhibited superior catalytic activity (propane conversion of 40.4 %, propylene selectivity of 96.0 %, 550 degrees C, WHSV=0.47 h(-1)) during PDH process. Furthermore, the relatively considerable performance of ZnOA/S-1 catalysts could help to offer a guidance on the design of efficient and low-cost catalysts for PDH reaction.
The high trap density (generally 10(16) to 10(18) cm(-3)) in thin films of organic semiconductors is the primary reason for the inferior charge-carrier mobility and large nonradiative recombination energy loss (Delta ...
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The high trap density (generally 10(16) to 10(18) cm(-3)) in thin films of organic semiconductors is the primary reason for the inferior charge-carrier mobility and large nonradiative recombination energy loss (Delta E-nr) in organic solar cells (OSCs), limiting improvement in power conversion efficiencies (PCEs). In this study, the trap density in OSCs is efficiently reduced via extending the donor core of nonfullerene acceptors (NFAs) from a heptacyclic unit to a nonacyclic unit. TTPIC-4F with a nonacyclic unit has stronger intramolecular and intermolecular interactions, affording higher crystallinity in thin films relative to its counterpart BTPIC-4F. Thus, the D18:TTPIC-4F-based device achieves a lower trap density of 4.02 x 10(15) cm(-3), comparable to some typical high-performance inorganic/hybrid semiconductors, with higher mobility and inhibited charge-carrier recombination in devices. Therefore, the D18:TTPIC-4F-based OSC exhibits an impressive PCE of 17.1% with a low Delta E-nr of 0.208 eV, which is the best known value for A-D-A-type NFAs. Therefore, extending the donor core of NFAs is an efficient method for suppressing trap states in OSCs for high PCEs.
Mg-Sr alloys are promising to fabricate orthopedic implants. The alloying of rare earth elements such as Gd may improve the comprehensive mechanical properties of Mg-Sr alloys. The information on the phase diagram and...
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Mg-Sr alloys are promising to fabricate orthopedic implants. The alloying of rare earth elements such as Gd may improve the comprehensive mechanical properties of Mg-Sr alloys. The information on the phase diagram and the microstructure development are required to design chemical composition and microstructure of Gd alloyed Mg-Sr alloys. The phase equilibria and the microstructure development in Mg-rich Mg-Gd-Sr alloys (Gd, Sr < 30 at. %) are experimentally investigated via phase identification, chemical analysis, and microstructure observation with respect to the annealed ternary alloys. The onset temperatures of liquid formation are measured by differential scanning calorimetry. A thermodynamic database of the Mg-rich Mg-Gd-Sr ternary system is developed for the first time via CALPHAD (CALculation of PHAse Diagram) approach assisted by First-Principles calculations. The thermodynamic calculations with the developed database enable a well reproduction of the experimental findings and the physical-metallurgical understanding of the microstructure formation in solidification and annealing.
Peristaltic flow is a common phenomenon in various natural physiological processes, such as the flow of blood and urine. Peristaltic pumps, which are a typical example of such transfer mechanisms, have extensive appli...
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Noninvasive genetic sampling greatly facilitates studies on the genetics, ecology, and conservation of threatened species. Species identification is often a prerequisite for noninvasive sampling-based biological studi...
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Noninvasive genetic sampling greatly facilitates studies on the genetics, ecology, and conservation of threatened species. Species identification is often a prerequisite for noninvasive sampling-based biological studies. Due to the low quantity and quality of genomic DNA from noninvasive samples, high-performance short-target PCR primers are necessary for DNA barcoding applications. The order Carnivora is characterized by an elusive habit and threatened status. In this study, we developed three pairs of short-target primers for identifying Carnivora species. The COI279 primer pair was suitable for samples with better DNA quality. The COI157a and COI157b primer pairs performed well for noninvasive samples and reduced the interference of nuclear mitochondrial pseudogenes (numts). COI157a could effectively identify samples from Felidae, Canidae, Viverridae, and Hyaenidae, while COI157b could be applied to samples from Ursidae, Ailuridae, Mustelidae, Procyonidae, and Herpestidae. These short-target primers will facilitate noninvasive biological studies and efforts to conserve Carnivora species.
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