Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and expe...Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and experiment. In the present review, we try to summarize recent advances in micro-alloying design of wrought Mg alloys from both theoretical and pragmatic perspectives, and provide fundamental data required for establishing the relationship between chemical composition and mechanical properties of Mg alloys. We start with theoretical attempts for understanding the mechanical properties of Mg alloys at different scales, by involving first principle calculations,molecular dynamics, cellular automata, and crystal plasticity. Then, the role of alloying elements is discussed for a series of promising Mg alloys such as Mg-Al, Mg-Zn, Mg-RE(rare-earth element), Mg-Sn, and Mg-Ca families.Potential challenges in the micro-alloying design of Mg alloys are highlighted at the end. The review is expected to provide helpful guidance for the intelligent design of novel wrought Mg alloys and inspire more innovative ideas in this field.展开更多
The ethoxycarbonyl isothiocyanate has been investigated by using supersonic jet Fourier transform microwave spectroscopy.Two sets of rotational spectra belonging to conformers TCC(with the backbone of C-C-O-C,C-O-C=O,...The ethoxycarbonyl isothiocyanate has been investigated by using supersonic jet Fourier transform microwave spectroscopy.Two sets of rotational spectra belonging to conformers TCC(with the backbone of C-C-O-C,C-O-C=O,and O-C(=O)-NCS being trans,cis,and cis arranged,respectively)and GCC(gauche,cis,and cis arrangement of the C-C-O-C,C-O-C=O,and O-C(=O)-NCS)have been measured and assigned.The measurements of13C,15N and34S mono-substituted species of the two conformers have also been performed.The comprehensive rotational spectroscopic investigations provide accurate values of rotational constants and14N quadrupole coupling constants,which lead to structural determinations of the two conformers of ethoxycarbonyl isothiocyanate.For conformer TCC,the values of Pcckeep constant upon isotopic substitution,indicating that the heavy atoms of TCC are effectively located in the ab plane.展开更多
According to the configuration,mixed-conducting membranes are classified as symmetric membranes and asymmetric membranes consisting of a thin dense layer and a porous support.In this study,these two kinds of SrCo0.4Fe...According to the configuration,mixed-conducting membranes are classified as symmetric membranes and asymmetric membranes consisting of a thin dense layer and a porous support.In this study,these two kinds of SrCo0.4Fe0.5Zr0.1O3-δ oxide-based membranes were systematically compared in terms of oxygen permeability and chemical stability,and their differences were elucidated by means of the theoretical calculation.For the oxygen permeability,the asymmetric membrane was greater than the symmetric membrane due to the significant decrease of bulk diffusion resistance in the thin dense layer of the asymmetric membrane.In regard to the chemical stability,the increase of oxygen partial pressure on the asymmetric membrane surface at CH4 side produced the stable time of over 1032h in partial oxidation of methane at 1123K,while the symmetric membrane was only of 528h.This study demonstrated that the asymmetric membrane was a promising geometrical configuration for the practical application.展开更多
OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the...OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the prediction of the valence shell electron pair repulsion theory of sp^(3) type.Delocalization stabilization energy is proposed to measure the contribution of delocalizedπ_(3)^(6) bond to energy decrease and proves to bring extra-stability to the molecule.These phenomena can be summarized as a kind of coordinating effect.展开更多
文摘基于最近发展的分子碎片共轭帽(molecular fractionation with conjugate caps,MFCC)方法,表皮生长因子受体(epidermal growth factor receptor,EGFR)与其抑制剂的相互作用能得以用完整的量子力学来计算,主要包括上市的Iressa[第一代美国食品及药物管理局(Food and Drug Administration,FDA)通过的药物]和4-苯胺基喹唑啉类抑制剂Tarceva(已上市)、CI-1033与EKI-785。对EGFR的完整体系(超过5 000个原子)与4-苯胺基喹唑啉类抑制剂之间的结合作用采用了量子力学计算方法。结合体系的量子能量计算,用Hartree-Fock与密度泛函理论(density functional theory,DFT)2种方法,EGFR与Tarceva之间的相互作用能基于它们两者复合物的晶体结构得到,而其他抑制剂与EGFR的相互作用能则通过分子对接软件预测的构型进行计算。利用MFCC方法,获得了量子相互作用能谱,清楚地给出了EGFR每个氨基酸片段与4-苯胺基喹唑啉类抑制剂之间的单个相互作用能。量子研究发现,4-苯胺基喹唑啉类抑制剂与EGFR的结合通过1个氢键和静电相互作用。Iressa、Tarceva、CI-1033、EKI-785与EGFR的结合能计算值分别为-40.23、-53.09、-33.92、-31.47kcal/mol(1cal=4.184J)。研究表明,Tarceva比第一代FDA通过的药物Iressa有更强的结合能力,而CI-1033、EKI-785则表现出一般的结合作用,另外,与MFCC计算的相互作用能谱相比,有一些相互作用在力场作用能谱中被明显高估。
基金the financial supports from the National Natural Science Foundation of China (Nos. U1764253, U2037601, 52001037, 51971044, 52101126)the National Defense Basic Scientific Research Program of China, China Postdoctoral Science Foundation (No. 2021M700566)+3 种基金the Natural Science Foundation of Chongqing, China (No. cstc2019jcyjmsxm X0234)Chongqing Science and Technology Commission, China (No. cstc2017zdcyzdzx X0006)Chongqing Scientific and Technological Talents Program, China (No. KJXX2017002)Qinghai Science and Technology Program, China (No. 2018-GX-A1)。
文摘Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and experiment. In the present review, we try to summarize recent advances in micro-alloying design of wrought Mg alloys from both theoretical and pragmatic perspectives, and provide fundamental data required for establishing the relationship between chemical composition and mechanical properties of Mg alloys. We start with theoretical attempts for understanding the mechanical properties of Mg alloys at different scales, by involving first principle calculations,molecular dynamics, cellular automata, and crystal plasticity. Then, the role of alloying elements is discussed for a series of promising Mg alloys such as Mg-Al, Mg-Zn, Mg-RE(rare-earth element), Mg-Sn, and Mg-Ca families.Potential challenges in the micro-alloying design of Mg alloys are highlighted at the end. The review is expected to provide helpful guidance for the intelligent design of novel wrought Mg alloys and inspire more innovative ideas in this field.
基金The support from the National Natural Science Foundation of China(No.22273009)Chongqing University。
文摘The ethoxycarbonyl isothiocyanate has been investigated by using supersonic jet Fourier transform microwave spectroscopy.Two sets of rotational spectra belonging to conformers TCC(with the backbone of C-C-O-C,C-O-C=O,and O-C(=O)-NCS being trans,cis,and cis arranged,respectively)and GCC(gauche,cis,and cis arrangement of the C-C-O-C,C-O-C=O,and O-C(=O)-NCS)have been measured and assigned.The measurements of13C,15N and34S mono-substituted species of the two conformers have also been performed.The comprehensive rotational spectroscopic investigations provide accurate values of rotational constants and14N quadrupole coupling constants,which lead to structural determinations of the two conformers of ethoxycarbonyl isothiocyanate.For conformer TCC,the values of Pcckeep constant upon isotopic substitution,indicating that the heavy atoms of TCC are effectively located in the ab plane.
基金Supported by the National Basic Research Program of China （2009CB623406）, the National Natural Science Foundation of China （20636020）, the National High Technology Research and Development Program of China （2006AA030204） and the Specialized Research Fund for the Doctoral Program of Higher Education of China （20060291003）.
文摘According to the configuration,mixed-conducting membranes are classified as symmetric membranes and asymmetric membranes consisting of a thin dense layer and a porous support.In this study,these two kinds of SrCo0.4Fe0.5Zr0.1O3-δ oxide-based membranes were systematically compared in terms of oxygen permeability and chemical stability,and their differences were elucidated by means of the theoretical calculation.For the oxygen permeability,the asymmetric membrane was greater than the symmetric membrane due to the significant decrease of bulk diffusion resistance in the thin dense layer of the asymmetric membrane.In regard to the chemical stability,the increase of oxygen partial pressure on the asymmetric membrane surface at CH4 side produced the stable time of over 1032h in partial oxidation of methane at 1123K,while the symmetric membrane was only of 528h.This study demonstrated that the asymmetric membrane was a promising geometrical configuration for the practical application.
基金supported by the Provincial Innovation and Entrepreneurship Training Program of Jiangsu Province(No.201910319079Y)。
文摘OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the prediction of the valence shell electron pair repulsion theory of sp^(3) type.Delocalization stabilization energy is proposed to measure the contribution of delocalizedπ_(3)^(6) bond to energy decrease and proves to bring extra-stability to the molecule.These phenomena can be summarized as a kind of coordinating effect.
