Aiming at understanding how intermetallic phases response when AA2024-T3 aluminium alloy is exposed to chloridecontainingaqueous medium, scanning electron microscopy was employed to provide morphological information o...Aiming at understanding how intermetallic phases response when AA2024-T3 aluminium alloy is exposed to chloridecontainingaqueous medium, scanning electron microscopy was employed to provide morphological information on alloy surfacebefore and after corrosion testing. Energy dispersive X-ray spectroscopy was carried out to determine compositional change inintermetallic particles. Atomic force microscopy was used to examine topographical variation introduced by the reactions ofintermetallic phases. Transmission electron microscopy combined with ultramicrotomy was carried out on dealloyed Al2CuMgparticles and their periphery region. It is found that dealloyed Al2CuMg particles exhibited porous, polycrystalline structurecomprised of body-centred cubic copper particles with sizes of 5 to 20 nm. Aluminium matrix started to trench in the periphery ofAl2CuMg particles at the early stage of dealloying. Development of trenching in Al.Cu.Fe.Mn.（Si） particle’s periphery was notuniform and took longer time to initiate than Al2CuMg dealloying. Localized corrosion at a cluster of Al2CuMg and Al2Cu particleswas mainly associated with Al2CuMg particles.展开更多
Dissolution kinetics of sodium carbonate is investigated with the image analysis method at the approach of single particle.The dissolution experiments are carried out in an aqueous solution under a series of controlle...Dissolution kinetics of sodium carbonate is investigated with the image analysis method at the approach of single particle.The dissolution experiments are carried out in an aqueous solution under a series of controlled temperature and p H.The selected sodium carbonate particles are all spherical with the same mass and diameter.The dissolution process is quantified with the measurement of particle diameter from dissolution images.The concentration of dissolved sodium carbonate in solvent is calculated with the measured diameter of particle.Both surface reaction model and mass transport model are implemented to determine the dissolution mechanism and quantify the dissolution rate constant at each experimental condition.According to the fitting results with both two models,it is clarified that the dissolution process at the increasing temperature is controlled by the mass transport of dissolved sodium carbonate travelling from particle surface into solvent.The dissolution process at the increasing pH is controlled by the chemical reaction on particle surface.Furthermore,the dissolution rate constant for each single spherical sodium carbonate particle is quantified and the results show that the dissolution rate constant of single spherical sodium carbonate increases significantly with the rising of temperature,but decreases with the increasing of pH conversely.展开更多
We propose an exactly solvable method to study the coherent two-colour photoassociation of an atomic Bose- Einstein condensate, by linearizing the bilinear atom-molecule coupling, which allows us to conveniently probe...We propose an exactly solvable method to study the coherent two-colour photoassociation of an atomic Bose- Einstein condensate, by linearizing the bilinear atom-molecule coupling, which allows us to conveniently probe the quantum dynamics and statistics of the system. By preparing different initial states of the atomic condensate, we can observe very different quantum statistical properties of the system by exactly calculating the quadrature- squeezed and mode-correlated functions.展开更多
基金Project(51201157)supported by the National Natural Science Foundation of ChinaProject(H052013A003)supported by the National Defense Technology Foundation,ChinaProject supported by the UK-ESPRC LATEST2 Program
文摘Aiming at understanding how intermetallic phases response when AA2024-T3 aluminium alloy is exposed to chloridecontainingaqueous medium, scanning electron microscopy was employed to provide morphological information on alloy surfacebefore and after corrosion testing. Energy dispersive X-ray spectroscopy was carried out to determine compositional change inintermetallic particles. Atomic force microscopy was used to examine topographical variation introduced by the reactions ofintermetallic phases. Transmission electron microscopy combined with ultramicrotomy was carried out on dealloyed Al2CuMgparticles and their periphery region. It is found that dealloyed Al2CuMg particles exhibited porous, polycrystalline structurecomprised of body-centred cubic copper particles with sizes of 5 to 20 nm. Aluminium matrix started to trench in the periphery ofAl2CuMg particles at the early stage of dealloying. Development of trenching in Al.Cu.Fe.Mn.（Si） particle’s periphery was notuniform and took longer time to initiate than Al2CuMg dealloying. Localized corrosion at a cluster of Al2CuMg and Al2Cu particleswas mainly associated with Al2CuMg particles.
基金the Institute of Particle and Science Engineering,University of Leeds and Procter&Gamble Newcastle Innovation Centre(UK)for partially funding the project
文摘Dissolution kinetics of sodium carbonate is investigated with the image analysis method at the approach of single particle.The dissolution experiments are carried out in an aqueous solution under a series of controlled temperature and p H.The selected sodium carbonate particles are all spherical with the same mass and diameter.The dissolution process is quantified with the measurement of particle diameter from dissolution images.The concentration of dissolved sodium carbonate in solvent is calculated with the measured diameter of particle.Both surface reaction model and mass transport model are implemented to determine the dissolution mechanism and quantify the dissolution rate constant at each experimental condition.According to the fitting results with both two models,it is clarified that the dissolution process at the increasing temperature is controlled by the mass transport of dissolved sodium carbonate travelling from particle surface into solvent.The dissolution process at the increasing pH is controlled by the chemical reaction on particle surface.Furthermore,the dissolution rate constant for each single spherical sodium carbonate particle is quantified and the results show that the dissolution rate constant of single spherical sodium carbonate increases significantly with the rising of temperature,but decreases with the increasing of pH conversely.
基金Supported by the National Basic Research Program of China under Grant No 2007CB307002, the National Natural Science Foundation of China under Grant Nos 10334010 and 10304020, the PCSIRT, the 111 Project （B07013）, Key International ST Cooperation Project under Grant No 2005DFA10170, the Cultivation Fund of the Key Scientific and Technical Innovation Project, the Ministry of Education of China under Grant No 704012, and the Wuhan Youth Chen-Guang Programme.
文摘We propose an exactly solvable method to study the coherent two-colour photoassociation of an atomic Bose- Einstein condensate, by linearizing the bilinear atom-molecule coupling, which allows us to conveniently probe the quantum dynamics and statistics of the system. By preparing different initial states of the atomic condensate, we can observe very different quantum statistical properties of the system by exactly calculating the quadrature- squeezed and mode-correlated functions.
