Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,in...Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale.展开更多
Isotope effect on superconductive transition temperature(T_c)is an essential indicator to examine whether the mechanism of superconductors is conventional.Unconventional isotope effect of BiS_(2)-based superconductors...Isotope effect on superconductive transition temperature(T_c)is an essential indicator to examine whether the mechanism of superconductors is conventional.Unconventional isotope effect of BiS_(2)-based superconductors has been previously reported in ambient-pressure tetragonal phase.However,to comprehensively ascertain the nature of superconductivity,the investigation of BiS_(2)-based system in high-pressure structure is highly desirable.In this work,we carried out the first-principles calculations of phonon spectra and superconductivity in high-pressure monoclinic phase of LaO_(0.5)F_(0.5)BiS_(2)with ^(32)S and ^(34)S,and observed that the corresponding isotope coefficient is 0.13≤α≤0.20.This value is much greater than that of BiS_(2)-based superconductors in ambient-pressure phase,but slightly smaller than that of conventional MgB_2.Taking into account the calculated T_(c) lower than experimental results,we finally conclude that the moderate phonon-mediated pairing plays a significant role in forming superconductivity of BiS_(2)-based system in high-pressure phase,moreover,the cooperative multiple paring interactions should also be considered.展开更多
Objective:To investigate the action mechanism of Rhizoma Atractylodis (Atractylodes lancea (Thunb.) Dc.) and Rhizoma Atractylodis Macrocephalae (Atractylodes macrocephala Koidz.),a two-herb ancient traditional Chinese...Objective:To investigate the action mechanism of Rhizoma Atractylodis (Atractylodes lancea (Thunb.) Dc.) and Rhizoma Atractylodis Macrocephalae (Atractylodes macrocephala Koidz.),a two-herb ancient traditional Chinese medicine used to treat type 2 diabetes mellitus,using molecular docking.Methods:The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform was searched for compounds in the two herbs and oral bioavailability and drug-likeness values were used to select compounds.The target proteins were selected based on a survey of the literature and related databases,and three receptors closely related to type 2 diabetes were chosen:insulin receptor,peroxisome proliferator activated receptor and dipeptidyl peptidase-Ⅳ.Molecular docking was performed using the CDocker module in Discovery Studio software.The interactions between targets and ligands were observed and analyzed,including the mode of action.Results:Nineteen compounds from the herbal pair interacted with the insulin receptor,the peroxisome proliferator activated receptor and dipeptidyl peptidase-Ⅳ.Among them,10 compounds bound successfully with all three targets,one compound bound with two targets,and eight compounds bound with one target.According to CDocker Interaction Energy,most compounds from the herbal pair had good binding activities with receptors and nine compounds had even higher scores than those of the original ligands.These data indicate that these compounds may be active in reducing blood glucose levels for the treatment of type 2 diabetes.Conclusion:Multiple compounds in the Rhizoma Atractylodis-Rhizoma Atractylodis Macrocephalae herbal pair can affect multiple human targets related to type 2 diabetes.展开更多
Confined geometry can change the defect structure and its properties.In this paper,we investigate numerically the dynamics of a dipole of ±1/2 parallel wedge disclination lines in a confined geometry：a thin hybr...Confined geometry can change the defect structure and its properties.In this paper,we investigate numerically the dynamics of a dipole of ±1/2 parallel wedge disclination lines in a confined geometry：a thin hybrid aligned nematic（HAN） cell,based on the Landau-de Gennes theory.When the cell gap d is larger than a critical value of 12ξ（where ξis the characteristic length for order-parameter change）,the pair annihilates.A pure HAN configuration without defect is formed in an equilibrium state.In the confined geometry of d ≤ 12ξ,the diffusion process is discovered for the first time and an eigenvalue exchange configuration is formed in an equilibrium state.The eigenvalue exchange configuration is induced by different essential reasons.When 10ξ 〈 d ≤ 12ξ,the two defects coalesce and annihilate.The biaxial wall is created by the inhomogeneous distortion of the director,which results in the eigenvalue exchange configuration.When d≤ 10ξ,the defects do not collide and the eigenvalue exchange configuration originates from the biaxial seeds concentrated at the defects.展开更多
In radar SAR interferometry (InSAR/DinSAR), a Tandem pair (ERS-1/2) is used for the realization of a DEM or the detection of deformations of a major event (e.g. earthquake) occurring between two acquisitions. The adva...In radar SAR interferometry (InSAR/DinSAR), a Tandem pair (ERS-1/2) is used for the realization of a DEM or the detection of deformations of a major event (e.g. earthquake) occurring between two acquisitions. The advantage of the Tandem pair is the time interval of 24 hours between the two captures. Generally, there is no temporal decorrelation considering the small difference in time between the acquisitions, which results in a good coherence. The coherence image is used indirectly in radar SAR interferometry as an indicator of the levels of confidence of the interferograms. It can be used in a direct way to identify and delimit the various movement zones which disturb the phase of the radar wave. The objective of this work is to show the utility and the effectiveness of the coherence image in the cartography of lakes and vegetation in a region at the Curvature of the Romanian Carpathians1. Between the two acquisitions dates of May 28 and 29, 1995, there was no geological process involving displacements in direction of the radar. This pair represents the only one among the other pairs which gave a good coherence for the whole scene. In the flat part, one notes a good coherence except for the lakes. They are well represented by very dark colours with zero coherence. In the part of high altitude, especially where there is vegetation, a bad coherence can be clearly seen. Using this image (coherence), one could distinguish the parts with vegetation in great movements due to the effects of the wind, therefore characterised by great heights. The coherence image thus makes it possible to delimit two natural elements in this area, the lakes and the vegetation. The lakes are well delimited, in particular when they are full as in the rain seasons. To show this utility and this effectiveness of the coherence image, we measured the surfaces and dimensions of the lakes based on the Tandem pair and to make a comparison with the existing data and to interpret the results obtained. The three lakes, located in the plain to the East and North-East of the Buza;u town, clearly appear in the coherence image.展开更多
This paper investigated the dynamics of a dipole of ±1/2 parallel wedge disclination lines in a confined geometry, based on Landau-de Gennes theory. The behavior of the pair depends on the competition between two...This paper investigated the dynamics of a dipole of ±1/2 parallel wedge disclination lines in a confined geometry, based on Landau-de Gennes theory. The behavior of the pair depends on the competition between two kinds of forces: the attractive force between the two defects, aggravating the annihilation process, and the anchoring forces coming from the substrates, inhibiting the annihilation process. There are three states when the system is equilibrium, divided by two critical thicknesses dc1 and dc2 (existing when r0≤15ξ, r0 is the initial distance between the two defects), both changing linearly with r0. When the cell gap d>dc1, the two defects coalesce and annihilate. The dynamics follows the function of r∝(t0-t)α during the annihilation step when d is sufficiently large, relative to r0, where r is the relative distance between the pair and t0 is the coalescence time. α decreases with the decrease of d or the increase of r0. The annihilation process has delicate structures: when r0≤15ξ and d>dc2 or r0>15ξand d>dc1, the two defects annihilate and the system is uniaxial at equilibrium state;when r0≤15ξ and dc2>d>dc1, the two defects coalesce and annihilate, and the system is not uniaxial, but biaxial in the region where the defects collide. When d≤dc1, the defects can be stable existence.展开更多
Molecularly imprinted polymers (MIPs) have great potential as adsorbents for selective adsorption and separation of nucleoside compounds,but effectively enhancing the affinity of recognition sites by adjusting the for...Molecularly imprinted polymers (MIPs) have great potential as adsorbents for selective adsorption and separation of nucleoside compounds,but effectively enhancing the affinity of recognition sites by adjusting the forces between template molecules and functional monomers remains an important challenge.In this work,a surface imprinting strategy was used to construct bowl-shaped molecularly imprinted composite sorbents (BHPN@MIPs) based on polydopamine (PDA) particles and have achieved selective separation and purification of 2'-deoxyadenosine (dA).Where by the base complementary pairing interaction of the combined template molecule d A and the pyrimidine functional monomer can enhance the preassembly force,and the hydrophilic bowl-shaped PDA can provide a larger storage space contact efficiency of d A in the test solution,causing the site utilization much higher and improving the kinetic adsorption performance.The equilibrium adsorption time and maximum adsorption capacity of60 min and 328.45μmol·g^(-1)were observed by static adsorption experiments,and the selectivity experimental results showed an imprinting factor IF of 1.30.After four adsorption–desorption cycles,the initial adsorption equilibrium adsorption capacity of BHPN@MIPs still retained 91.14%.By evaluating the selective adsorption of d A in spiked human serum solutions,BHPN@MIPs can be used to selectively enrich and analyze target d A in complex biological samples.展开更多
基金the National Natural Science Foundation of China(22279044,12034002,and 22202080)the Project for Self-Innovation Capability Construction of Jilin Province Development and Reform Commission(2021C026)+1 种基金Jilin Province Science and Technology Development Program(20210301009GX)the Fundamental Research Funds for the Central Universities.
文摘Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale.
基金Project supported by the National Natural Science Foundation of China(Grant No.12175107)the Natural Science Foundation of Nanjing University of Posts and Telecommunications(Grant Nos.NY219087 and NY220038)。
文摘Isotope effect on superconductive transition temperature(T_c)is an essential indicator to examine whether the mechanism of superconductors is conventional.Unconventional isotope effect of BiS_(2)-based superconductors has been previously reported in ambient-pressure tetragonal phase.However,to comprehensively ascertain the nature of superconductivity,the investigation of BiS_(2)-based system in high-pressure structure is highly desirable.In this work,we carried out the first-principles calculations of phonon spectra and superconductivity in high-pressure monoclinic phase of LaO_(0.5)F_(0.5)BiS_(2)with ^(32)S and ^(34)S,and observed that the corresponding isotope coefficient is 0.13≤α≤0.20.This value is much greater than that of BiS_(2)-based superconductors in ambient-pressure phase,but slightly smaller than that of conventional MgB_2.Taking into account the calculated T_(c) lower than experimental results,we finally conclude that the moderate phonon-mediated pairing plays a significant role in forming superconductivity of BiS_(2)-based system in high-pressure phase,moreover,the cooperative multiple paring interactions should also be considered.
基金This study was supported by the National Natural Science Foundation of China(81473800).
文摘Objective:To investigate the action mechanism of Rhizoma Atractylodis (Atractylodes lancea (Thunb.) Dc.) and Rhizoma Atractylodis Macrocephalae (Atractylodes macrocephala Koidz.),a two-herb ancient traditional Chinese medicine used to treat type 2 diabetes mellitus,using molecular docking.Methods:The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform was searched for compounds in the two herbs and oral bioavailability and drug-likeness values were used to select compounds.The target proteins were selected based on a survey of the literature and related databases,and three receptors closely related to type 2 diabetes were chosen:insulin receptor,peroxisome proliferator activated receptor and dipeptidyl peptidase-Ⅳ.Molecular docking was performed using the CDocker module in Discovery Studio software.The interactions between targets and ligands were observed and analyzed,including the mode of action.Results:Nineteen compounds from the herbal pair interacted with the insulin receptor,the peroxisome proliferator activated receptor and dipeptidyl peptidase-Ⅳ.Among them,10 compounds bound successfully with all three targets,one compound bound with two targets,and eight compounds bound with one target.According to CDocker Interaction Energy,most compounds from the herbal pair had good binding activities with receptors and nine compounds had even higher scores than those of the original ligands.These data indicate that these compounds may be active in reducing blood glucose levels for the treatment of type 2 diabetes.Conclusion:Multiple compounds in the Rhizoma Atractylodis-Rhizoma Atractylodis Macrocephalae herbal pair can affect multiple human targets related to type 2 diabetes.
基金supported by the National Natural Science Foundation of China(Grant No.11374087)the Key Subject Construction Project of Hebei Province University
文摘Confined geometry can change the defect structure and its properties.In this paper,we investigate numerically the dynamics of a dipole of ±1/2 parallel wedge disclination lines in a confined geometry：a thin hybrid aligned nematic（HAN） cell,based on the Landau-de Gennes theory.When the cell gap d is larger than a critical value of 12ξ（where ξis the characteristic length for order-parameter change）,the pair annihilates.A pure HAN configuration without defect is formed in an equilibrium state.In the confined geometry of d ≤ 12ξ,the diffusion process is discovered for the first time and an eigenvalue exchange configuration is formed in an equilibrium state.The eigenvalue exchange configuration is induced by different essential reasons.When 10ξ 〈 d ≤ 12ξ,the two defects coalesce and annihilate.The biaxial wall is created by the inhomogeneous distortion of the director,which results in the eigenvalue exchange configuration.When d≤ 10ξ,the defects do not collide and the eigenvalue exchange configuration originates from the biaxial seeds concentrated at the defects.
文摘In radar SAR interferometry (InSAR/DinSAR), a Tandem pair (ERS-1/2) is used for the realization of a DEM or the detection of deformations of a major event (e.g. earthquake) occurring between two acquisitions. The advantage of the Tandem pair is the time interval of 24 hours between the two captures. Generally, there is no temporal decorrelation considering the small difference in time between the acquisitions, which results in a good coherence. The coherence image is used indirectly in radar SAR interferometry as an indicator of the levels of confidence of the interferograms. It can be used in a direct way to identify and delimit the various movement zones which disturb the phase of the radar wave. The objective of this work is to show the utility and the effectiveness of the coherence image in the cartography of lakes and vegetation in a region at the Curvature of the Romanian Carpathians1. Between the two acquisitions dates of May 28 and 29, 1995, there was no geological process involving displacements in direction of the radar. This pair represents the only one among the other pairs which gave a good coherence for the whole scene. In the flat part, one notes a good coherence except for the lakes. They are well represented by very dark colours with zero coherence. In the part of high altitude, especially where there is vegetation, a bad coherence can be clearly seen. Using this image (coherence), one could distinguish the parts with vegetation in great movements due to the effects of the wind, therefore characterised by great heights. The coherence image thus makes it possible to delimit two natural elements in this area, the lakes and the vegetation. The lakes are well delimited, in particular when they are full as in the rain seasons. To show this utility and this effectiveness of the coherence image, we measured the surfaces and dimensions of the lakes based on the Tandem pair and to make a comparison with the existing data and to interpret the results obtained. The three lakes, located in the plain to the East and North-East of the Buza;u town, clearly appear in the coherence image.
文摘This paper investigated the dynamics of a dipole of ±1/2 parallel wedge disclination lines in a confined geometry, based on Landau-de Gennes theory. The behavior of the pair depends on the competition between two kinds of forces: the attractive force between the two defects, aggravating the annihilation process, and the anchoring forces coming from the substrates, inhibiting the annihilation process. There are three states when the system is equilibrium, divided by two critical thicknesses dc1 and dc2 (existing when r0≤15ξ, r0 is the initial distance between the two defects), both changing linearly with r0. When the cell gap d>dc1, the two defects coalesce and annihilate. The dynamics follows the function of r∝(t0-t)α during the annihilation step when d is sufficiently large, relative to r0, where r is the relative distance between the pair and t0 is the coalescence time. α decreases with the decrease of d or the increase of r0. The annihilation process has delicate structures: when r0≤15ξ and d>dc2 or r0>15ξand d>dc1, the two defects annihilate and the system is uniaxial at equilibrium state;when r0≤15ξ and dc2>d>dc1, the two defects coalesce and annihilate, and the system is not uniaxial, but biaxial in the region where the defects collide. When d≤dc1, the defects can be stable existence.
基金financially supported by the National Natural Science Foundation of China (22078132 and 22108103)Open Funding Project of the National Key Laboratory of Biochemical Engineering (2021KF-02)+3 种基金China Postdoctoral Science Foundation (2021M691301)Jiangsu Agricultural Independent Innovation Fund Project (CX(21)3079)Graduate Research Innovation Program of Jiangsu Province (KYCX20-3040)China Postdoctoral Science Foundation (2021M691301)。
文摘Molecularly imprinted polymers (MIPs) have great potential as adsorbents for selective adsorption and separation of nucleoside compounds,but effectively enhancing the affinity of recognition sites by adjusting the forces between template molecules and functional monomers remains an important challenge.In this work,a surface imprinting strategy was used to construct bowl-shaped molecularly imprinted composite sorbents (BHPN@MIPs) based on polydopamine (PDA) particles and have achieved selective separation and purification of 2'-deoxyadenosine (dA).Where by the base complementary pairing interaction of the combined template molecule d A and the pyrimidine functional monomer can enhance the preassembly force,and the hydrophilic bowl-shaped PDA can provide a larger storage space contact efficiency of d A in the test solution,causing the site utilization much higher and improving the kinetic adsorption performance.The equilibrium adsorption time and maximum adsorption capacity of60 min and 328.45μmol·g^(-1)were observed by static adsorption experiments,and the selectivity experimental results showed an imprinting factor IF of 1.30.After four adsorption–desorption cycles,the initial adsorption equilibrium adsorption capacity of BHPN@MIPs still retained 91.14%.By evaluating the selective adsorption of d A in spiked human serum solutions,BHPN@MIPs can be used to selectively enrich and analyze target d A in complex biological samples.
