An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstru...
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An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstruc- rural investigations, hierarchical nanotwinned lamellar AISc bundles with embedded micron-/submicron-sized AI2Sc and AISc2 are observed. The as-cast alloy displays a unique act of ultrahigh strength of -1.85 GPa to- gether with pronounced work hardening and a large plasticity of -14%. Further microstructural investigations on deformed specimens indicate that abundant hierarchical nanotwinned lamellar AISc bundles are effective to dissipate localization of shear stress or block dislocations from spreading throughout the alloy and hinder the propagation of mierocracks formed by local stress transition.
Because of both ozone gas and ozone solution are instable which limits the application of ozone, to solve the storage problem, it is necessary to find a kind ofideal ozone carrier which can combine ozone as an ＂ozoni...
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Because of both ozone gas and ozone solution are instable which limits the application of ozone, to solve the storage problem, it is necessary to find a kind ofideal ozone carrier which can combine ozone as an ＂ozonic compound＂ in which the bond strength between ozone and carrier should not be too high or too low, to appropriately release ozone from the ozonic compound. Combining Criegee’s three-step reaction mechanism of ozone and olefins, the charge, covalent bond levels and energy levels of ozone, ethylene, butadiene and their ozonic compounds were calculated by the first-principles calculation method based on density functional theory methods. The stability of the ozonide, or the bond strength between ozone and ions of carrier were controlled felicitously to release ozone from the ozonide with proper velocity. Ozone antimicrobial was composed on the above principle. It can be used conveniently, especially for common families.
Chiral separation that is closely related to daily life is a meaningful research. Polysaccharide-(e.g., cellulose, amylose derivatives) based chiral packing materials afford powerful chiral stationary phases(CSPs) tow...
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Chiral separation that is closely related to daily life is a meaningful research. Polysaccharide-(e.g., cellulose, amylose derivatives) based chiral packing materials afford powerful chiral stationary phases(CSPs) toward a broad range of racemic compounds. However, considering the explosive growth of specific chiral drugs, the separation efficiencies of these CSPs need further improvement, which calls for new approaches and strategies. Smart polymers can change their physical or chemical properties dynamically and reversibly according to the external stimuli(e.g., thermo-, pH, solvent, ion, light, critical parameters for chromatographic separation) exerted on them, subsequently resulting in tunable changes in the macroscopic properties of materials. In addition to their excellent controllability, the introduction of chiral characteristics into the backbones or side-chains of smart polymers provides a promising route to realize reversibly conformational transition in response to the chiral analytes. This dramatic transition may significantly improve the performance of materials in chiral separation through modulating the enantioselective interactions between materials and analytes. With the help of chirality-responsive polymers, intelligent and switchable CSPs could be developed and applied in column-liquid chromatography. In these systems, the elution order or enantioselectivity of chiral drugs can be precisely modulated, which will help to solve many challenging problems that involve complicated enantiomers. In this paper we introduce some typical examples of smart polymers that serve as the basis for a discussion of emerging developments of CPSs, and then briefly outline the recent CSPs based on natural and certain synthetic polymers.
Dense Nb/Nb5Si3 composites were fabricated via spark plasma sintering technology using Nb, Si, and Al elemental powders as raw materials. The microstructttres of the synthesised composites were analyzed through scanni...
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Dense Nb/Nb5Si3 composites were fabricated via spark plasma sintering technology using Nb, Si, and Al elemental powders as raw materials. The microstructttres of the synthesised composites were analyzed through scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. The results show that the composites consisted of residual Nb particle phase and Nb5Si3 phase. The microstructure of the Nb/ Nb5Si3 in situ composites was evidently affected by Al addition, which prompted the formation of the Al3Nb10Si3 phase. In addition, the Rockwell hardness of the composites decreased with the increase in AI additions. The Rockwell hardness of Nb-20Si is 60HRC, which decreased to approximately 52.7 HRC when the Al content increased to 15 at%. The oxidation resistance of the Nb/NbsSi3 in situ composites significantly improved with the increase in Al addition.
A facile procedure for the synthesis ofdithieno[5,6-b：11,12-b＇]coronene-2,3,8,9-tetracarboxylic tetra（2- ethylhexyl）ester （DTCTI＇E-EH） from readily available perylene-3,4,9,10-tetracaroboxylic dianhydride is de...
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A facile procedure for the synthesis ofdithieno[5,6-b：11,12-b＇]coronene-2,3,8,9-tetracarboxylic tetra（2- ethylhexyl）ester （DTCTI＇E-EH） from readily available perylene-3,4,9,10-tetracaroboxylic dianhydride is described. The electronic properties of DTCTTE-EH were elucidated on the basis of UV-vis spectra, emission spectrum and electrochemical measurement, which demonstrate that DTCTTE is a new class of components for promising semiconducting materials.
Pb- or Bi-based perovskite oxides have been widely studied and used because of their large ferroelectric polarization features induced by stereochemically active 6s2 lone pair electrons. It is intriguing whether this ...
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K2Ti4O9 nanowhiskers were synthesised via stearic acid method by using potassium hydroxide (KOH) and tetrabutyl titanate (Ti(OC4H9)4) as raw materials. The effects of molar ratio of tetrabutyl titanate and KOH (RT/K),...
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Polycrystalline ultra-thick β-SiC films have been grown on graphite substrates via halide chemical vapour deposition method by using tetrachlorosilane (SiCl4) as silicon source, whereas methane (CH4), acetylene (C2H2...
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Schwann cells play a key role in peripheral nerve growth and regeneration. The aim of this study was to evaluate the effects of RGD peptides on Schwann cell behavior, and to identify the effects of the modified PDLLA ...
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Schwann cells play a key role in peripheral nerve growth and regeneration. The aim of this study was to evaluate the effects of RGD peptides on Schwann cell behavior, and to identify the effects of the modified PDLLA films with RGD in vivo. The results revealed that RGD coating with the concentration of 100-500 ug/mL promoted the cell proliferation and boosted the cell migration. Molecularly, RGD coating also enhanced the expression of the proliferation related genes （c-fos and c-jun） and the cell behavior related genes （actin, tublin, tau and MAP1） at first stages of the seeding, which is similar to the effects from laminin coating. In vivo, RGD addition improved the recovery efficiency of the transected nerve in regard of the more survived Schwann cells in vivo and the formation of more mature myelin sheath. Taken together, RGD peptides are good candidates to enhance the biocompatibility of the biomaterials and facilitate the peripheral nerve regeneration by prompting responses in Schwann ceils.
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