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Modified embedded-atom interatomic potential for Co-W and Al-W systems 被引量:1
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作者 董卫平 陈铮 Byeong-Joo LEE 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期907-914,共8页
A semi-empirical interatomic potential formalism,the second-nearest-neighbor modified embedded-atom method(2NN MEAM),has been applied to obtaining interatomic potentials for the Co-W and Al-W binary system using previ... A semi-empirical interatomic potential formalism,the second-nearest-neighbor modified embedded-atom method(2NN MEAM),has been applied to obtaining interatomic potentials for the Co-W and Al-W binary system using previously developed MEAM potentials of Co,Al and W.The potential parameters were determined by fitting the experimental data on the enthalpy of formation,lattice parameter,melting point and elastic constants.The present potentials generally reproduce the fundamental physical properties of the Co-W and Al-W systems accurately.The lattice parameters,the enthalpy of formation,the thermal stability and the elastic constants match well with experiment and the first-principles results.The enthalpy of mixing and the enthalpy of formation and mixing of liquid are in good agreement with CALPHAD calculations.The potentials can be easily combined with already-developed MEAM potentials for binary cobalt systems and can be used to describe Co-Al-W-based multicomponent alloys,especially for interfacial properties. 展开更多
关键词 modified embedded-atom method Co-W system Al-W system atomistic simulation
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Cofactor engineering in cyanobacteria to overcome imbalance between NADPH and NADH: A mini review 被引量:4
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作者 Jongmoon Park Yunnam Choi 《Frontiers of Chemical Science and Engineering》 SCIE EI CAS CSCD 2017年第1期66-71,共6页
Cyanobacteria can produce useful renewable fuels and high-value chemicals using sunlight and atmo- spheric carbon dioxide by photosynthesis. Genetic manip- ulation has increased the variety of chemicals that cyanobact... Cyanobacteria can produce useful renewable fuels and high-value chemicals using sunlight and atmo- spheric carbon dioxide by photosynthesis. Genetic manip- ulation has increased the variety of chemicals that cyanobacteria can produce. However, their uniquely abundant NADPH-pool, in other words insufficient supply of NADH, tends to limit their production yields in case of utilizing NADH-dependent enzyme, which is quite common in heterotrophic microbes. To overcome this cofactor imbalance and enhance cyanobacterial fuel and chemical production, various approaches for cofactor engineering have been employed. In this review, we focus on three approaches: (1) utilization of NADPH- dependent enzymes, (2) increasing NADH production, and (3) changing cofactor specificity of NADH-dependent enzymes from NADH to NADPH. 展开更多
关键词 NADH-dependent enzyme NADPH-depen-dent enzyme TRANSHYDROGENASE site-directed mutagenesis enzyme engineering
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FeH_(x)的稳定性以及氢在地球核-幔边界的传输 被引量:1
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作者 何宇 Duck Young Kim +3 位作者 Viktor V.Struzhkin Zachary M.Geballe Vitali Prakapenka 毛河光 《Science Bulletin》 SCIE EI CAS CSCD 2023年第14期1567-1573,M0004,共8页
地球内部水和铁的反应可以生成铁-氢合金.研究铁-氢合金可以增进对地球内部氢传输的认知.我们通过高压实验和第一性原理计算的方法,对高温高压下具有面心立方结构(fcc)FeH_(x)(x≤1)的相稳定性、密度、氢的输运性质和熔点进行了系统研究... 地球内部水和铁的反应可以生成铁-氢合金.研究铁-氢合金可以增进对地球内部氢传输的认知.我们通过高压实验和第一性原理计算的方法,对高温高压下具有面心立方结构(fcc)FeH_(x)(x≤1)的相稳定性、密度、氢的输运性质和熔点进行了系统研究,证实了FeH_(x)在165 GPa时的稳定性.通过高温的分子动力学模拟,发现FeH_(x)在下地幔温压下转变为超离子态.在超离子态FeH_(x)中,氢离子快速扩散表现出类似流体的性质,扩散系数高达3.710^(-4)cm~2s^(-1).与超离子态冰类似,氢离子的快速扩散可以导致体系的熵增,使其的熔化温度增加.FeH_(x)可以将氢从地幔传输到外地核,使得外核成为H的潜在储库,并在核-幔边界上方留下了富氧的块状结构. 展开更多
关键词 离子态 第一性原理计算 氢离子 相稳定性 地球内部 熔化温度 高压实验 分子动力学模拟
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