Ti-based hydrogen storage alloy is one of the most common solid-state hydrogen storage materials due to its high hydrogen absorption capacity, low dehydrogenation temperature and rich resources. This paper mainly pres...Ti-based hydrogen storage alloy is one of the most common solid-state hydrogen storage materials due to its high hydrogen absorption capacity, low dehydrogenation temperature and rich resources. This paper mainly presents the influence of several different preparation methods of Ti-based hydrogen storage alloys on the hydrogen storage performance including traditional preparation methods (smelting, rapid quenching and mechanical alloying) and novel methods by plastic deformation (cold rolling, equal channel angular pressing and high-pressure torsion). The microstructure analysis and hydrogen storage properties of Ti-based alloy are summarized thoroughly corresponding with the preparation processes mentioned above. It was found that slight introduction of lattice defects including dislocation, grain boundary, sub-grain boundary and cracks by severe plastic deformation (SPD) was beneficial to improve the hydriding/dehydriding kinetic characteristic. However, the nonuniform composition and residual stress of the alloy may be caused by SPD, which is not conducive to the improvement of hydrogen storage capacity. In the future, it would be expected that new methods and technologies combined with dopant and modification are applied to Ti-based hydrogen storage alloys to make breakthroughs in practical application.展开更多
Purpose:To investigate the association between high anisometropia and the area of choroidal neovascularization (CNV) induced by krypton laser in guinea pigs and better understand the pathogenesis and prevention of myo...Purpose:To investigate the association between high anisometropia and the area of choroidal neovascularization (CNV) induced by krypton laser in guinea pigs and better understand the pathogenesis and prevention of myopic CNV. Methods:.Nine 3-week old male guinea pigs with anisometropia > 6.00D were randomly assigned to three groups according to examination date after laser photocoagulation (7d, 14d and 28d). All animals underwent refraction. The eye with higher myopia was used as the experimental eye, and the other as the control eye..All eyes received repeated multi-wavelength krypton laser photocoagulation treatments (wavelength: 532 nm; laser power: 400 mW; spot diameter: 50 μm; exposure time: 0.1s). Fundus photography and indocyanine green angiography (ICGA) were performed. Afterwards, the animals were sacrificed immediately,.and the eyes were enucleated and processed for histopathologic examination and flat mounts. Results: CNV appeared at 7d after laser treatment. The area of CNV peaked at 14d, and decrease in area and the presence of scarring was noted at 28 d..CNV was present in 66.7% of eyes by ICGA at 14 d..CNV could be observed under light microscopy at all three time points..At 14 d,.flat mount showed the neovascular plexus around the lesion. Semi-quantitative analysis revealed that the area of CNV in treated eyes was greater than that of control eyes. Conclusion:.Since the mechanism of CNV in this study resembles that of CNV in pathological myopia, this model can be used to investigate the etiology, pathogenesis and treatment of CNV in pathological myopia.展开更多
Octanes in alkylation products obtained from industrial alkylation were studied by batch experiments.More than eight octane isomers were identified and quantified by gas chromatography-mass spectrometry.Based on a cla...Octanes in alkylation products obtained from industrial alkylation were studied by batch experiments.More than eight octane isomers were identified and quantified by gas chromatography-mass spectrometry.Based on a classic carbenium ion mechanism,the carbocation transition states in concentrated sulfuric acid catalyzed alkylation were investigated using quantum-chemical simulations and predicted the concentration and octane isomerization products including trimethylpentane and dimethylhexane as well as the formation of heavier compounds that resulted from the oligomerization of octane and butene.The agreement between model calculations and experimental data was quite satisfactory.Calculation results indicated that composition and content of trimethylpentanes in the alkylation products were 2,2,4-trimethylpentane>2,3,3-trimethylpentane>2,3,4-trimethylpentane>2,2,3-trimethylpentane whether the 2-butene or i-butene acts as olefin.Heavier compounds in the alkylate were primarily formed by the oligomerization of dimethylhexane with 1-butene.Hopefully,the carbocation transition state models developed in this work will be useful for understanding the product distributions of octane in alkylation products.展开更多
文摘Ti-based hydrogen storage alloy is one of the most common solid-state hydrogen storage materials due to its high hydrogen absorption capacity, low dehydrogenation temperature and rich resources. This paper mainly presents the influence of several different preparation methods of Ti-based hydrogen storage alloys on the hydrogen storage performance including traditional preparation methods (smelting, rapid quenching and mechanical alloying) and novel methods by plastic deformation (cold rolling, equal channel angular pressing and high-pressure torsion). The microstructure analysis and hydrogen storage properties of Ti-based alloy are summarized thoroughly corresponding with the preparation processes mentioned above. It was found that slight introduction of lattice defects including dislocation, grain boundary, sub-grain boundary and cracks by severe plastic deformation (SPD) was beneficial to improve the hydriding/dehydriding kinetic characteristic. However, the nonuniform composition and residual stress of the alloy may be caused by SPD, which is not conducive to the improvement of hydrogen storage capacity. In the future, it would be expected that new methods and technologies combined with dopant and modification are applied to Ti-based hydrogen storage alloys to make breakthroughs in practical application.
文摘Purpose:To investigate the association between high anisometropia and the area of choroidal neovascularization (CNV) induced by krypton laser in guinea pigs and better understand the pathogenesis and prevention of myopic CNV. Methods:.Nine 3-week old male guinea pigs with anisometropia > 6.00D were randomly assigned to three groups according to examination date after laser photocoagulation (7d, 14d and 28d). All animals underwent refraction. The eye with higher myopia was used as the experimental eye, and the other as the control eye..All eyes received repeated multi-wavelength krypton laser photocoagulation treatments (wavelength: 532 nm; laser power: 400 mW; spot diameter: 50 μm; exposure time: 0.1s). Fundus photography and indocyanine green angiography (ICGA) were performed. Afterwards, the animals were sacrificed immediately,.and the eyes were enucleated and processed for histopathologic examination and flat mounts. Results: CNV appeared at 7d after laser treatment. The area of CNV peaked at 14d, and decrease in area and the presence of scarring was noted at 28 d..CNV was present in 66.7% of eyes by ICGA at 14 d..CNV could be observed under light microscopy at all three time points..At 14 d,.flat mount showed the neovascular plexus around the lesion. Semi-quantitative analysis revealed that the area of CNV in treated eyes was greater than that of control eyes. Conclusion:.Since the mechanism of CNV in this study resembles that of CNV in pathological myopia, this model can be used to investigate the etiology, pathogenesis and treatment of CNV in pathological myopia.
基金International(regional)cooperation and exchange program(Grant No.21961160740)the open foundation of State Key Laboratory of Chemical Engineering(Grant No.SKL-ChE-19B02)the North University of China Graduate Science and Technology Project(Grant Nos.20191621,20191626).
文摘Octanes in alkylation products obtained from industrial alkylation were studied by batch experiments.More than eight octane isomers were identified and quantified by gas chromatography-mass spectrometry.Based on a classic carbenium ion mechanism,the carbocation transition states in concentrated sulfuric acid catalyzed alkylation were investigated using quantum-chemical simulations and predicted the concentration and octane isomerization products including trimethylpentane and dimethylhexane as well as the formation of heavier compounds that resulted from the oligomerization of octane and butene.The agreement between model calculations and experimental data was quite satisfactory.Calculation results indicated that composition and content of trimethylpentanes in the alkylation products were 2,2,4-trimethylpentane>2,3,3-trimethylpentane>2,3,4-trimethylpentane>2,2,3-trimethylpentane whether the 2-butene or i-butene acts as olefin.Heavier compounds in the alkylate were primarily formed by the oligomerization of dimethylhexane with 1-butene.Hopefully,the carbocation transition state models developed in this work will be useful for understanding the product distributions of octane in alkylation products.
