How proteins fold up in nature remains one of the major problems unsolved in biophysics and molecular biology. Thermodynamic approach assumes the native state has minimum free energy, and aims to find the absolute fre...
How proteins fold up in nature remains one of the major problems unsolved in biophysics and molecular biology. Thermodynamic approach assumes the native state has minimum free energy, and aims to find the absolute free energy minimum. Dynamic approach assumes protein folding is stochastic in nature, and aims to find the statistically most probable structures. Combining the advantages of the thermodynamic and dynamic approaches, a multi-scale simulation of protein folding is carried out. First, the key structures, representing minimum or maximum free energies on the energy landscape, are identified by genetic algorithms （GA）. Then, the dynamic behaviors of the folding pathways for these structures are examined through explicit solvent molecular dynamics （MD） simulations. An integrated view of protein folding can thus be obtained through the two steps above. We used this method to a model peptide RN24, constituted by 13 amino-terminal residues of ribonuclease A （sequence Ac-AETAAAKFLRAHA-NH2）. Both thermodynamic and kinetic properties of the peptide folding can be detected with much less computational cost in comparison to traditional simulations. Three most populated conformations are observed, including anti-parallel β-hairpin, parallel β-sheet and α-helix. The energetic barriers separating these three populated structures are comparable to the kinetic energy of the peptide, meaning that the transformation between these states can be easily triggered by kinetic perturbations. This multi-scale simulation is compared with both experiments and traditional MD simulations, showing its reasonableness and potential in reducing computational cost, and further improvement of the method is discussed.
＜正＞In recent years, nanostructured materials with hollow structure have attracted much attention because of their special physical and chemical properties with respect to solid materials, which are potentially appl...
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＜正＞In recent years, nanostructured materials with hollow structure have attracted much attention because of their special physical and chemical properties with respect to solid materials, which are potentially applicable in photocatalysis, drug delivery, energy conversion and storage systems, chemical sensors, biotechnology, and so on[1]. Herein, we report a simple and general synthesis of multiple-shell hollow
Rechargeable lithium ion batteries (LIBs) have become one of the dominant power sources for portable electronic devices. Cobalt oxide (Co 3 O 4 ) as LIB anode material receives extensive attention since it is expected...
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Rechargeable lithium ion batteries (LIBs) have become one of the dominant power sources for portable electronic devices. Cobalt oxide (Co 3 O 4 ) as LIB anode material receives extensive attention since it is expected to have a high capacity and excellent cycling performance. Although the capacity has been improved, the practical use of Co 3 O 4 as anode for LIBs is still hindered by their poor cycling performance and/or low rate capability. To circumvent these issues, one effective way is to use hollow micro-/nano-structures as anode for LIBs. In this article, multi-shelled Co 3 O 4 hollow microspheres were synthesized in high yield and purity through a hard-template method. By controlling the size and diffusion rate of the hydrated metal cations, and the ion absorption capability of carbonaceous sphere templates, we can accurately control the number of shells and the interior structures. When tested as the anode materials for LIBs, these multi-shelled Co 3 O 4 hollow microspheres exhibit excellent rate capacity, good cycling performance and ultrahigh specific capacity (1615.8 mAh g -1 at the thirtieth cycle for triple-shelled Co 3 O 4 ). The superior performance in LIBs originates from the porous hollow multi-shelled microstructure, which guarantees more lithium storage sites, a shorter Li-ion diffusion length and sufficient void space to buffer the volume expansion. Given their facile synthesis and the improved performance, it can be expected that these multi-shelled Co 3 O 4 hollow microspheres will open a new avenue for the development of the next generation of LIBs with higher specific capacity, better cycling performance and higher rate capacity.
The feedwater temperature of thermal power unit always decreases with the electrical *** order to solve this problem, the ejector heat pump is integrated with the regenerative *** live steam is used to inject the extr...
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The feedwater temperature of thermal power unit always decreases with the electrical *** order to solve this problem, the ejector heat pump is integrated with the regenerative *** live steam is used to inject the extraction steam of regenerative system, then the mixture steam is led to the added heater (working in low load condition, named as low load condition heater bellow) to heat the feedwater.
In the preparation of materials, diffusion and reaction are two general but important parameters influencing the structure of materials. In a diffusion-limited condition, a non-compact structure is easily formed while...
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In the preparation of materials, diffusion and reaction are two general but important parameters influencing the structure of materials. In a diffusion-limited condition, a non-compact structure is easily formed while a compact structure is usually formed in a reaction-limited condition. When the diffusion and reaction play a joint role, their compromise would dominate the structure of materials. In this talk, we first take the precipitation of calcium carbonate as an example to discover the role of diffusion and reaction in shaping the structure of materials. By adjusting the diffusion and reaction rate in a double-diffusion reactor, we synthesize a snow-shaped particle which is a new morphology of calcium carbonate [1], as shown in Figure 1. To disclose its formation mechanism, we conduct microscopic characterizations and computer simulation. The obtained results suggest that the snow-shaped particle is built up by an aggregation of nanoparticles and the compromise between diffusion and reaction plays an important role for the formation of snow-shaped particles. Further experiments and the simulating results support the role of compromise in shaping ***, we extended our study to the shape-controlled synthesis of other particles by manipulating the diffusion and reaction. The obtained results have also confirmed the compromise effect. All these results will be presented in this talk.
作者：
Jinghai LiThe EMMS Group
State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China
This presentation reviews a 3-decade research on meso-scale modeling of various complex systems at the Institute of Process engineering, Chinese Academy of Sciences (IPE, CAS). Starting with the study of particle clus...
This presentation reviews a 3-decade research on meso-scale modeling of various complex systems at the Institute of Process engineering, Chinese Academy of Sciences (IPE, CAS). Starting with the study of particle clustering phenomenon, the EMMS (energy-minimization multiscale) model was established for gas-solid fluidization systems by analyzing the compromise between dominant mechanisms, which was then verified, and further extended to other multiphase systems. In recent years, the EMMS principle was used to define a multi-scale computation paradigm – the EMMS paradigm, featuring the structural similarity between problem, modeling, software and hardware, which was implemented by constructing a supercomputer with a capacity of 1.0 Petaflops. This paradigm was believed to be promising for realizing the virtual process engineering (VPE). The EMMS principle was also believed to be a universal one for all meso-scale phenomena, that is, could be the principle for the emerging science – Meso-science. This presentation reviews the principles, methodology, computation and application of the EMMS paradigm, and gives perspective for VPE and meso-science.
Mg and Mg-based metal hydrides are viewed as one of the most promising hydrogen storage materials due to their high capacity,light weight,low price and little impact on the ***,the practical application is obstructed ...
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Mg and Mg-based metal hydrides are viewed as one of the most promising hydrogen storage materials due to their high capacity,light weight,low price and little impact on the ***,the practical application is obstructed by their high stability,which results in the bad kinetics and high reaction temperature,especially the high operating temperature.
Experiments were conducted to study pool boiling heat transfer on ultra-light porous metal foam surfaces,with deionized water as working *** metal foams have pore densities from 30 to 60ppi(pores per inch) and thickne...
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ISBN:
(纸本)9781479933372
Experiments were conducted to study pool boiling heat transfer on ultra-light porous metal foam surfaces,with deionized water as working *** metal foams have pore densities from 30 to 60ppi(pores per inch) and thickness from2.0 to *** effects of heat flux,surface superheat,liquid temperature and characteristic parameters of metal foam on pool boiling heat transfer were *** is found that metal foam surfaces can significantly enhance pool boiling heat transfer and lower the surface superheat at the boiling *** density and thickness exists an optimal value to strengthen boiling heat *** boiling heat transfer coefficient on the metal foam surfaces is about 2～3 times of those on the plain *** significant reasons are due to the distinct nature of high porosity and multi-scale pore sizes of metal *** larger pores help to release the created vapor while the smaller pores help to suck the liquid toward the heater surface,decreasing the shear stress at the vaporliquid interface for the counter-current flow.
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