The interaction of tetra- and hexa-coordinated compounds of cytosine(C) and guanine(G) with metal cations Ca(2+), Mg(2+), Mn(2+), Ni(2+), Cu(2+), and Zn(2+) have been calculated by using the B3LYP/6-31G method at the ...The interaction of tetra- and hexa-coordinated compounds of cytosine(C) and guanine(G) with metal cations Ca(2+), Mg(2+), Mn(2+), Ni(2+), Cu(2+), and Zn(2+) have been calculated by using the B3LYP/6-31G method at the 6-31G(d, p) basis set, while the remaining coordination bonds are saturated by water molecules ((H(2)O)(4)). All geometries were optimized without symmetry restrictions. Comparing the interaction energies we obtained the orders of selectivity of C and G for the above metal ions as follows: (a)Cu(2+)>(a)Ni(2+)>(a)Mg(2+)>(a)Mg(2+)>(b)Cu(2+)>(a)Mn(2+)>(b)Zn(2+)> Ni(2+) and (a)Cu(2+)>(a)Ni(2+> a)Zn(2+)>(a)Mg(2+)>(b)Cu(2+)>(a)Mn(2+)>(b)Zn(2+)>(b)Ni(2+) respectively ((a,b) represent tetra- and hexa-coordinated, respectively), which are in good agreement with the experimental facts. Interaction energies of complexes provide a comparatively reliable quantification of the selectivity of dimethyl phosphate anion for the studied metal ions. In addition, the influence of coordination number and coordination structure on the interaction energy and the variation of ionic energy were discussed sufficiently. After analyzing the interaction energies of two kinds of complexes, the 'mutual selectivity'as well as the nature of the interaction between metal ions and ligands was revealed.展开更多
Objective:To study the expression and significance of ECP, 25-(OH)D3 and M2 receptors in children with acute attack of asthma.Methods: Seventy children with bronchial asthma who first visited our hospital from Septemb...Objective:To study the expression and significance of ECP, 25-(OH)D3 and M2 receptors in children with acute attack of asthma.Methods: Seventy children with bronchial asthma who first visited our hospital from September 2016 to September 2018 were divided into chronic persistence group, remission group and acute attack group. Thirty healthy children who underwent physical examination in our hospital were selected and divided into control group. The levels of ECP, 25-(OH) D3 and M2 receptors were analyzed by ELISA, and Pearson correlation analysis was performed.Results: Compared with the control group, the levels of ECP and M2 receptors in chronic persistence group, remission group and acute attack group increased, while the levels of 25-(OH)D3 decreased, with statistical difference (P<0.05). The levels of ECP and M2 receptors in acute attack group were higher than those in chronic persistence group, and the levels of 25-(OH)D3 were lower than those in chronic persistence group (P<0.05). The levels of ECP and M2 receptors in acute attack group were higher than those in remission group, and the levels of 25-(OH)D3 were lower than those in remission group (P<0.05). Compared with mild children, the levels of ECP and M2 receptors increased and 25-(OH)D3 decreased in moderate and severe children (P<0.05). Compared with moderate children, the levels of ECP and M2 receptors increased and 25-(OH)D3 decreased in severe children (P<0.05).There was a negative correlation between ECP and 25-(OH)D3 (r=-0.380, P=0.038);a negative correlation between 25-(OH)D3 and M2 receptor (r=-0.448,P=0.013);and a positive correlation between ECP and M2 receptor (r=0.450,P=0.013).Conclusions:The expression of ECP and M2 receptors increased during the acute attack of bronchial asthma in children, while the expression of 25-hydroxyvitamin D3 decreased during the acute attack of bronchial asthma in children. The correlation among ECP, 25-(OH) D3 and M2 receptors is significant in the clinical diagnosis of acute attack of bronchial asthma in children.展开更多
Surface structures of Pt-Sn and Pt-Fe bimetallic catalysts have been investigated by means of M?ssbauer spectroscopy, Pt-L111-edge EXAFS and Hz-adsorption. The results showed that the second component, such as Sn or F...Surface structures of Pt-Sn and Pt-Fe bimetallic catalysts have been investigated by means of M?ssbauer spectroscopy, Pt-L111-edge EXAFS and Hz-adsorption. The results showed that the second component, such as Sn or Fe, remained in the oxidative state and dispersed on the γ-Al2O3 surface after reduction, while Pt was completely reduced to the metallic state and dispersed on either the metal oxide surface or the γ-A1203, surface. By correlating the distribution of Pt species on different surfaces with the reaction and adsorption performances, it is proposed that two kinds of active Pt species existed on the surfaces of both catalysts, namedM1 sites and M2 sites. M1 sites are the sites in which Pt directly anchored on the γ-Al2O3 surface, while M2 sites are those in which Pt anchored on the metal oxide surface. MI sites are favorable for low temperature H2 adsorption, and responsible for the hydrogenolysis reaction and carbon deposition, while M2 sites which adsorb more H2 at higher temperature, are more resistant to the deactivation due to less carbon deposition, and provide major contribution to the dehydrogenation reaction.展开更多
Exploring high-efficient catalysts for hydrogen evolution reaction(HER)has become very urgeht for resolving the energy related issues.Recently,two-dimensional layered MoS2 and its heterostructures with graphene or oth...Exploring high-efficient catalysts for hydrogen evolution reaction(HER)has become very urgeht for resolving the energy related issues.Recently,two-dimensional layered MoS2 and its heterostructures with graphene or other traditional photocatalysts have presented great potentials for electrocatalytic and photocatalytic HER applications.On-site investigations of the atomic-scale structures and local electronic properties of the catalytically active sites are the key points for understanding the internal mechanisms,which however are hard to be achievec from the practical systems.Hereby,this review focuses on the recent progresses on the on-site scanning tunneling microscopy/spectroscopy investigations of the atomic structures and electronic properties of the ultrahigh-vacuum deposited and chemical vapor deposition(CVD)synthesized monolayer MoS2 and MoSz/graphene vertical stacks on the electrodes of Au(111)and Au foils.The correlations between the respective HER activities,edge types and edge electronic states are comparatively introduced.Secondly,this review also introduces thephotocatalytic HER applications of CVD-grown MoS2/WS2 and WS/MoS2 vertical stacks on Au foils,mainly considering of their type-ll band.alignments and the novel interlayer charge transfer behaviors.Finally,future research directions are also proposed for in-depth understanding of the catalytic mechanism,as well as for exploring more efficient HER catalysts.展开更多
Chemical vapor deposition (CVD) is the most efficient method to grow large-area two dimensional (2D) transition metal dichiacogenides (TMDCs) in high quality.Monolayer molybdenum disulfide (MoS2) and seed-assistant ar...Chemical vapor deposition (CVD) is the most efficient method to grow large-area two dimensional (2D) transition metal dichiacogenides (TMDCs) in high quality.Monolayer molybdenum disulfide (MoS2) and seed-assistant are the mostly selected 2D TMDC and growth strategy for such CVD processes,respectively.Though the advantages of seed catalysts in facilitating the nucleation,achieving higher yield and better repeatability,as well as their effects on the morphologies of as-grown MoS2 have been studied,the influence of seeding promoters on both optical and electrical properties of as-grown monolayer MoS2 is not known comprehensively,which is indeed critical for understanding fundamental physics and developing practical application of such emerging 2D semiconductors.In this report,we systematically investigated the effect of different seeding promoters on the properties of CVD-grown monolayer MoS2.It is found that different seed molecules lead to different impacts on the optical and electrical properties of as-grown monolayer MoS2.Among three different seed catalysts (perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS),copper phthalocyanine (CuPc),and crystal violet (CV)),PTAS performs better in obtaining large area monolayer MoS2 with good optical quality and high electrical mobility than the other two.Our work gives a guide for modifying the properties of as-grown monolayer MoS2 and other 2D transition metal dichalcogenides in seeding promoters-assisted synthesis process.展开更多
This work focuses on fundamental understanding of microstructure evolution of nanostructured ferritic alloy(NFA) and 25 vol.% Cr3C2 coated Si C(Cr3C2@Si C)-NFA composite during spark plasma sintering at950°C and ...This work focuses on fundamental understanding of microstructure evolution of nanostructured ferritic alloy(NFA) and 25 vol.% Cr3C2 coated Si C(Cr3C2@Si C)-NFA composite during spark plasma sintering at950°C and the following thermal treatment at 1000°C. A unique bi-phase microstructure with distinct Cr-rich and Si-rich phases has been observed for the 25 vol.% Cr3C2@Si C-NFA composite, while for the NFA sample, the traditional large grain microstructure remains. Grain sizes are significantly smaller for the25 vol.% Cr3C2@Si C-NFA composite compared to those for the pure NFA, which can be attributed to the presence of grain boundary phases in the composite sample. During the thermal treatment, microstructure features can be directly correlated with the dissolution kinetics and phase diagrams calculated using Thermo-Calc/DICTRA/PRISMA~?.展开更多
基金This work was supported by the Startup Foundation of Scientific Research for the Elitists introduced into Jinan University
文摘The interaction of tetra- and hexa-coordinated compounds of cytosine(C) and guanine(G) with metal cations Ca(2+), Mg(2+), Mn(2+), Ni(2+), Cu(2+), and Zn(2+) have been calculated by using the B3LYP/6-31G method at the 6-31G(d, p) basis set, while the remaining coordination bonds are saturated by water molecules ((H(2)O)(4)). All geometries were optimized without symmetry restrictions. Comparing the interaction energies we obtained the orders of selectivity of C and G for the above metal ions as follows: (a)Cu(2+)>(a)Ni(2+)>(a)Mg(2+)>(a)Mg(2+)>(b)Cu(2+)>(a)Mn(2+)>(b)Zn(2+)> Ni(2+) and (a)Cu(2+)>(a)Ni(2+> a)Zn(2+)>(a)Mg(2+)>(b)Cu(2+)>(a)Mn(2+)>(b)Zn(2+)>(b)Ni(2+) respectively ((a,b) represent tetra- and hexa-coordinated, respectively), which are in good agreement with the experimental facts. Interaction energies of complexes provide a comparatively reliable quantification of the selectivity of dimethyl phosphate anion for the studied metal ions. In addition, the influence of coordination number and coordination structure on the interaction energy and the variation of ionic energy were discussed sufficiently. After analyzing the interaction energies of two kinds of complexes, the 'mutual selectivity'as well as the nature of the interaction between metal ions and ligands was revealed.
基金Key projects funded by the science and technology bureau of Chenzhou city(No.CZ2013065).
文摘Objective:To study the expression and significance of ECP, 25-(OH)D3 and M2 receptors in children with acute attack of asthma.Methods: Seventy children with bronchial asthma who first visited our hospital from September 2016 to September 2018 were divided into chronic persistence group, remission group and acute attack group. Thirty healthy children who underwent physical examination in our hospital were selected and divided into control group. The levels of ECP, 25-(OH) D3 and M2 receptors were analyzed by ELISA, and Pearson correlation analysis was performed.Results: Compared with the control group, the levels of ECP and M2 receptors in chronic persistence group, remission group and acute attack group increased, while the levels of 25-(OH)D3 decreased, with statistical difference (P<0.05). The levels of ECP and M2 receptors in acute attack group were higher than those in chronic persistence group, and the levels of 25-(OH)D3 were lower than those in chronic persistence group (P<0.05). The levels of ECP and M2 receptors in acute attack group were higher than those in remission group, and the levels of 25-(OH)D3 were lower than those in remission group (P<0.05). Compared with mild children, the levels of ECP and M2 receptors increased and 25-(OH)D3 decreased in moderate and severe children (P<0.05). Compared with moderate children, the levels of ECP and M2 receptors increased and 25-(OH)D3 decreased in severe children (P<0.05).There was a negative correlation between ECP and 25-(OH)D3 (r=-0.380, P=0.038);a negative correlation between 25-(OH)D3 and M2 receptor (r=-0.448,P=0.013);and a positive correlation between ECP and M2 receptor (r=0.450,P=0.013).Conclusions:The expression of ECP and M2 receptors increased during the acute attack of bronchial asthma in children, while the expression of 25-hydroxyvitamin D3 decreased during the acute attack of bronchial asthma in children. The correlation among ECP, 25-(OH) D3 and M2 receptors is significant in the clinical diagnosis of acute attack of bronchial asthma in children.
文摘Surface structures of Pt-Sn and Pt-Fe bimetallic catalysts have been investigated by means of M?ssbauer spectroscopy, Pt-L111-edge EXAFS and Hz-adsorption. The results showed that the second component, such as Sn or Fe, remained in the oxidative state and dispersed on the γ-Al2O3 surface after reduction, while Pt was completely reduced to the metallic state and dispersed on either the metal oxide surface or the γ-A1203, surface. By correlating the distribution of Pt species on different surfaces with the reaction and adsorption performances, it is proposed that two kinds of active Pt species existed on the surfaces of both catalysts, namedM1 sites and M2 sites. M1 sites are the sites in which Pt directly anchored on the γ-Al2O3 surface, while M2 sites are those in which Pt anchored on the metal oxide surface. MI sites are favorable for low temperature H2 adsorption, and responsible for the hydrogenolysis reaction and carbon deposition, while M2 sites which adsorb more H2 at higher temperature, are more resistant to the deactivation due to less carbon deposition, and provide major contribution to the dehydrogenation reaction.
基金This work was supported by the National Natural Science Foundation of China(Nos.51861135201,5147200i,21473001,51290272,and 61774003)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(No.KF201601).
文摘Exploring high-efficient catalysts for hydrogen evolution reaction(HER)has become very urgeht for resolving the energy related issues.Recently,two-dimensional layered MoS2 and its heterostructures with graphene or other traditional photocatalysts have presented great potentials for electrocatalytic and photocatalytic HER applications.On-site investigations of the atomic-scale structures and local electronic properties of the catalytically active sites are the key points for understanding the internal mechanisms,which however are hard to be achievec from the practical systems.Hereby,this review focuses on the recent progresses on the on-site scanning tunneling microscopy/spectroscopy investigations of the atomic structures and electronic properties of the ultrahigh-vacuum deposited and chemical vapor deposition(CVD)synthesized monolayer MoS2 and MoSz/graphene vertical stacks on the electrodes of Au(111)and Au foils.The correlations between the respective HER activities,edge types and edge electronic states are comparatively introduced.Secondly,this review also introduces thephotocatalytic HER applications of CVD-grown MoS2/WS2 and WS/MoS2 vertical stacks on Au foils,mainly considering of their type-ll band.alignments and the novel interlayer charge transfer behaviors.Finally,future research directions are also proposed for in-depth understanding of the catalytic mechanism,as well as for exploring more efficient HER catalysts.
基金National Natural Science Foundation of China (Nos. 61774040, 61774042, and 51772317)National Young 1000 Talent Plan of China+1 种基金Shanghai Municipal Natural Science Foundation (Nos. 16ZR1402500, 16ZR1442700, and 17ZR1446500)Opening project of State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences, the National Key R&D program (No. 2017YFF0206106).
文摘Chemical vapor deposition (CVD) is the most efficient method to grow large-area two dimensional (2D) transition metal dichiacogenides (TMDCs) in high quality.Monolayer molybdenum disulfide (MoS2) and seed-assistant are the mostly selected 2D TMDC and growth strategy for such CVD processes,respectively.Though the advantages of seed catalysts in facilitating the nucleation,achieving higher yield and better repeatability,as well as their effects on the morphologies of as-grown MoS2 have been studied,the influence of seeding promoters on both optical and electrical properties of as-grown monolayer MoS2 is not known comprehensively,which is indeed critical for understanding fundamental physics and developing practical application of such emerging 2D semiconductors.In this report,we systematically investigated the effect of different seeding promoters on the properties of CVD-grown monolayer MoS2.It is found that different seed molecules lead to different impacts on the optical and electrical properties of as-grown monolayer MoS2.Among three different seed catalysts (perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS),copper phthalocyanine (CuPc),and crystal violet (CV)),PTAS performs better in obtaining large area monolayer MoS2 with good optical quality and high electrical mobility than the other two.Our work gives a guide for modifying the properties of as-grown monolayer MoS2 and other 2D transition metal dichalcogenides in seeding promoters-assisted synthesis process.
基金supported financially by the Office of Nuclear Energy of Department of Energy(No.#DE-NE0008264)。
文摘This work focuses on fundamental understanding of microstructure evolution of nanostructured ferritic alloy(NFA) and 25 vol.% Cr3C2 coated Si C(Cr3C2@Si C)-NFA composite during spark plasma sintering at950°C and the following thermal treatment at 1000°C. A unique bi-phase microstructure with distinct Cr-rich and Si-rich phases has been observed for the 25 vol.% Cr3C2@Si C-NFA composite, while for the NFA sample, the traditional large grain microstructure remains. Grain sizes are significantly smaller for the25 vol.% Cr3C2@Si C-NFA composite compared to those for the pure NFA, which can be attributed to the presence of grain boundary phases in the composite sample. During the thermal treatment, microstructure features can be directly correlated with the dissolution kinetics and phase diagrams calculated using Thermo-Calc/DICTRA/PRISMA~?.
