In the 1940s, KIRKENDALL showed that diffusion in binary solid solutions cannot be described by only one diffusion coefficient. Rather, one has to consider the diffusivity of both species. His findings changed the tre...In the 1940s, KIRKENDALL showed that diffusion in binary solid solutions cannot be described by only one diffusion coefficient. Rather, one has to consider the diffusivity of both species. His findings changed the treatment of diffusion data and the theory of diffusion itself. A diffusion-based framework was successfully employed to explain the behaviour of the Kirkendall plane. Nonetheless, the complexity of a multiphase diffusion zone and the morphological evolution during interdiffusion requires a physico-chemical approach. The interactions in binary and more complex systems are key issues from both the fundamental and technological points of view. This paper reviews the Kirkendall effect from the circumstances of its discovery to recent developments in its understanding, with broad applicability in materials science and engineering.展开更多
Efficient parallel screening of combinatorial libraries is one of the most challenging aspects of the high- throughput （HT） heterogeneous catalysis workflow. Today, a number of methods have been used in HT catalyst ...Efficient parallel screening of combinatorial libraries is one of the most challenging aspects of the high- throughput （HT） heterogeneous catalysis workflow. Today, a number of methods have been used in HT catalyst studies, including various optical, mass-spectrometry, and gas- chromatography techniques. Of these, rapid-scanning Fourier-transform infrared （FTIR） imaging is one of the fastest and most versatile screening techniques. Here, the new design of the 16-channel HT reactor is presented and test results for its accuracy and reproducibility are shown. The performance of the system was evaluated through the oxidation of CO over commercial Pd/AI203 and cobalt oxide nanoparticles synthesized with different reducer-reductant molar ratios, surfactant types, metal and surfactant concentrations, synthesis temperatures, and ramp rates.展开更多
Multiple-energy aluminium （AI＋） implantation into 4H-SiC （0001） epilayer and activation anneal with a graphite encapsnlation layer were investigated in this paper. Measurements showed that the implanted Ak＋ box ...Multiple-energy aluminium （AI＋） implantation into 4H-SiC （0001） epilayer and activation anneal with a graphite encapsnlation layer were investigated in this paper. Measurements showed that the implanted Ak＋ box doping profile was formed and a high ion activation ratio of 78% was achieved by 40 rain annealing at 1600℃ using a horizontal chemical vapor deposition （CVD） reactor. The step bunching effect associated with the high temper：lture post implantation activation annealing （PIA） process was dramatically suppressed by using the graphite encapsulation layer. And a flat and smooth surface with a small average surface roughness （RMS） value of around 1.16 nm was achieved for the implanted 4H-SiC after the PIA process. It was demonstrated that this surface protection technique is a quite effective process for 4H-SiC power devices fabrication.展开更多
Understanding the processes of protein adsorption/desorption on nanopartieles＇ surfaces is important for the development of new nanotechnology involving biomaterials; however, an atomistic resolution picture for thes...Understanding the processes of protein adsorption/desorption on nanopartieles＇ surfaces is important for the development of new nanotechnology involving biomaterials; however, an atomistic resolution picture for these processes and for the simultaneous protein conformational change is missing. Here, we report the adsorption of protein GB 1 on a polystyrene nanoparticle surface using atomistic molecular dynamic simulations. Enabled by metadynamics, we explored the relevant phase space and identified three protein states, each involving both the adsorbed and desorbed modes. We also studied the change of the secondary and tertiary structures of GB 1 during adsorption and the dominant interactions between the protein and surface in different adsorption stages. The results we obtained from simulation were found to be more adequate and complete than the previous one. We believe the model presented in this paper, in comparison with the previous ones, is a better theoretical model to understand and explain the experimental results.展开更多
文摘In the 1940s, KIRKENDALL showed that diffusion in binary solid solutions cannot be described by only one diffusion coefficient. Rather, one has to consider the diffusivity of both species. His findings changed the treatment of diffusion data and the theory of diffusion itself. A diffusion-based framework was successfully employed to explain the behaviour of the Kirkendall plane. Nonetheless, the complexity of a multiphase diffusion zone and the morphological evolution during interdiffusion requires a physico-chemical approach. The interactions in binary and more complex systems are key issues from both the fundamental and technological points of view. This paper reviews the Kirkendall effect from the circumstances of its discovery to recent developments in its understanding, with broad applicability in materials science and engineering.
基金the South Carolina Smart State Center for Strategic Approaches to the Generation of Electricity (SAGE) for funding
文摘Efficient parallel screening of combinatorial libraries is one of the most challenging aspects of the high- throughput （HT） heterogeneous catalysis workflow. Today, a number of methods have been used in HT catalyst studies, including various optical, mass-spectrometry, and gas- chromatography techniques. Of these, rapid-scanning Fourier-transform infrared （FTIR） imaging is one of the fastest and most versatile screening techniques. Here, the new design of the 16-channel HT reactor is presented and test results for its accuracy and reproducibility are shown. The performance of the system was evaluated through the oxidation of CO over commercial Pd/AI203 and cobalt oxide nanoparticles synthesized with different reducer-reductant molar ratios, surfactant types, metal and surfactant concentrations, synthesis temperatures, and ramp rates.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61006060, 61176070)
文摘Multiple-energy aluminium （AI＋） implantation into 4H-SiC （0001） epilayer and activation anneal with a graphite encapsnlation layer were investigated in this paper. Measurements showed that the implanted Ak＋ box doping profile was formed and a high ion activation ratio of 78% was achieved by 40 rain annealing at 1600℃ using a horizontal chemical vapor deposition （CVD） reactor. The step bunching effect associated with the high temper：lture post implantation activation annealing （PIA） process was dramatically suppressed by using the graphite encapsulation layer. And a flat and smooth surface with a small average surface roughness （RMS） value of around 1.16 nm was achieved for the implanted 4H-SiC after the PIA process. It was demonstrated that this surface protection technique is a quite effective process for 4H-SiC power devices fabrication.
基金supported by the National Natural Science Foundation of China(Grant Nos.11774158,11274157,31671026,and 11334004)the National Basic Research and Development Program of China(Grant No.2013CB834100)Priority Academic Program Development(PAPD)Project of Jiangsu Higher Education Institutions
文摘Understanding the processes of protein adsorption/desorption on nanopartieles＇ surfaces is important for the development of new nanotechnology involving biomaterials; however, an atomistic resolution picture for these processes and for the simultaneous protein conformational change is missing. Here, we report the adsorption of protein GB 1 on a polystyrene nanoparticle surface using atomistic molecular dynamic simulations. Enabled by metadynamics, we explored the relevant phase space and identified three protein states, each involving both the adsorbed and desorbed modes. We also studied the change of the secondary and tertiary structures of GB 1 during adsorption and the dominant interactions between the protein and surface in different adsorption stages. The results we obtained from simulation were found to be more adequate and complete than the previous one. We believe the model presented in this paper, in comparison with the previous ones, is a better theoretical model to understand and explain the experimental results.
