Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high perfo...Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.展开更多
The structural stability and magnetic properties of the icosahedral Ni13, Ni13^+1 and Ni13^-1 clusters have been obtained by utilizing all-electron density functional theory with the generalized gradient approximatio...The structural stability and magnetic properties of the icosahedral Ni13, Ni13^+1 and Ni13^-1 clusters have been obtained by utilizing all-electron density functional theory with the generalized gradient approximations for the exchange-correlation energy. The calculated results show that the ground states of neutral and charged clusters all favour a D3d structure, a distorted icosahedron, due to the Jahn-Teller effect. The radial distortions caused by doping one electron and by doping one hole are opposite to each other. Doping one electron will result in a 1/2 decrease and doping one hole will result in a 1/2 increase of the total spin. Both increasing interatomic spacing and decreasing coordination will lead to an enhancement of the spin magnetic moments for Nil3 clusters.展开更多
The food sources of aquacultured Apostichopus japonicus and the trophic levels of organisms in a sea cucumber(A. japonicus) and prawn(Penaeus japonica) polyculture system in a saltwater pond in Zhuanghe, Liaoning ...The food sources of aquacultured Apostichopus japonicus and the trophic levels of organisms in a sea cucumber(A. japonicus) and prawn(Penaeus japonica) polyculture system in a saltwater pond in Zhuanghe, Liaoning Province were examined using carbon and nitrogen stable isotopes. Across organisms, δ13C ranged from(–25.47±0.20)‰ to(–16.48±0.17)‰(mean±SD), and δ15N ranged from(4.23±0.49)‰ to(12.44±0.09)‰. The δ13C and δ15N contents of A. japonicus, P. japonica and Fenneropenaeus chinensis were comparatively higher than those of other organisms. Values of δ13C and δ15N revealed that P. japonica, Hemigrapsus sanguineus and Neomysis japonica comprised the largest component of the diet of A. japonicus. The mean trophic level of the organisms in this saltwater pond polyculture system was(2.75±0.08). P. japonica, A. japonicus, F. chinensis,Synechogobius hasta and Neomysis japonica were in the 3rd trophic level(2–3); jellyfish, H. sanguineus and zooplankton were in the 2nd trophic level(1–2); and Enteromorpha prolifera, benthic microalgae, periphyton and suspended matter primarily consisting of phytoplankton, bacteria and humus were in the primary trophic level(0–1).展开更多
Due to the dependence of the chemical and physical properties of the bimetallic nanoparticles(NPs) on their structures,a fundamental understanding of their structural characteristics is crucial for their syntheses a...Due to the dependence of the chemical and physical properties of the bimetallic nanoparticles(NPs) on their structures,a fundamental understanding of their structural characteristics is crucial for their syntheses and wide applications. In this article, a systematical atomic-level investigation of Au–Pd bimetallic NPs is conducted by using the improved particle swarm optimization(IPSO) with quantum correction Sutton–Chen potentials(Q-SC) at different Au/Pd ratios and different sizes. In the IPSO, the simulated annealing is introduced into the classical particle swarm optimization(PSO) to improve the effectiveness and reliability. In addition, the influences of initial structure, particle size and composition on structural stability and structural features are also studied. The simulation results reveal that the initial structures have little effects on the stable structures, but influence the converging rate greatly, and the convergence rate of the mixing initial structure is clearly faster than those of the core-shell and phase structures. We find that the Au–Pd NPs prefer the structures with Au-rich in the outer layers while Pd-rich in the inner ones. Especially, when the Au/Pd ratio is 6:4, the structure of the nanoparticle(NP) presents a standardized Pd(core) Au(shell) structure.展开更多
A dpoamic deecription of the marked disparity in economic developmentbetween China' s Middle-West Resion and Along-Coast Resion is presented.Some qualitative investigation is siven to the expected prospects of the...A dpoamic deecription of the marked disparity in economic developmentbetween China' s Middle-West Resion and Along-Coast Resion is presented.Some qualitative investigation is siven to the expected prospects of the Middle-West Resion with some preliminary stratesic suggestions proposed.展开更多
Similar material simulation test W9-15 101 fully mechanized caving face with was carried out in a geological model of large mining height in the Liuhuanggou Colliery, in Xinjiang Uigur Autonomous Region. The roof over...Similar material simulation test W9-15 101 fully mechanized caving face with was carried out in a geological model of large mining height in the Liuhuanggou Colliery, in Xinjiang Uigur Autonomous Region. The roof overlying strata movement law in the stope of a fully mechanized caving face with large mining height was studied and show that the roof overlying strata in the stope of a fully mechanized caving face with large mining height can be formed into a stable arch structure; the fracture rock beam is formed resembling a "bond beam", but it has essentially the structure of "multi-span beams" under the big structure of the stable arch. The roof overlying strata movement law in the stope of a fully mechanized caving face with large mining height is similar to that of the common, fully mechanized caving stope, which is determined by the deformation and instability of the structure of "multi-span beams". But because of the differences between the mining heights, the peak pressure in the stope of a fully mechanized caving face with large mining height is smaller while the affected area of abutment pressure is wider in the front of the working face; this is the obvious difference in abutment pressure between the stope of a fully mechanized caving face with large mining height and that of the common.展开更多
Obtaining an electrocorticograms(ECoG)signal requires an invasive procedure in which brain activity is recorded from the cortical surface.In contrast,obtaining electroencephalograms(EEG)recordings requires the non-inv...Obtaining an electrocorticograms(ECoG)signal requires an invasive procedure in which brain activity is recorded from the cortical surface.In contrast,obtaining electroencephalograms(EEG)recordings requires the non-invasive procedure of recording the brain activity from the scalp surface,which allows EEG recordings to be performed more easily on healthy humans.In this work,a technique previously used to study spatial-temporal patterns of brain activity on animal ECoG was adapted for use on EEG.The main issues are centered on solving the problems introduced by the increment on the interelectrode distance and the procedure to detect stable frames.The results showed that spatial patterns of beta and gamma activity can also be extracted from the EEG signal by using stable frames as time markers for feature extraction.This adapted technique makes it possible to take advantage of the cognitive and phenomenological awareness of a normal healthy subject.展开更多
The elTcct of different dimension stabilization treatments on the dimension stability of SiC_(p)/Al composites were investigated by the measurement of microyield strength,microcreep properties,dimension,residual stres...The elTcct of different dimension stabilization treatments on the dimension stability of SiC_(p)/Al composites were investigated by the measurement of microyield strength,microcreep properties,dimension,residual stress and analyses of transmission electron microscopy.Results show that the heat cycle dimension stabilization techniques could efficiently decrease the residual stress,stabilize the dimension change,and increase resistance to microplastic deformation.The main reason was that the heat cycle dimension stabilization techniques might form stable dislocation structure in the SiC_(p)/A1 composites.展开更多
The acquisition of polymer-grade(≥99.95%)C_(2)H_(4) poses a challenge due to the presence of ethane(C_(2)H_(6))having similar physical and chemical properties.Consequently,the one-step purification of C_(2)H_(4) beco...The acquisition of polymer-grade(≥99.95%)C_(2)H_(4) poses a challenge due to the presence of ethane(C_(2)H_(6))having similar physical and chemical properties.Consequently,the one-step purification of C_(2)H_(4) becomes a crucial and demanding process.In this study,we synthesized ZIF-78 with a GME configuration using different metal sources(Zn,Co).Both substances have been identified as ethane-selective adsorbents with excellent thermal stability.The Brunauer Emmett Teller(BET)surface area of ZIF-78-Co(748 m^(2)/g)surpasses that of ZIF-78-Zn(585 m^(2)/g),and the former exhibits a higher Q_(st) value for C_(2)H_(6),resulting in enhanced adsorption capacity for C_(2)H_(6)(50.61 cm^(3)/g)and selectivity for C_(2)H_(6)/C_(2)H_(4)(1.71)compared to ZIF-78-Zn(48.97 cm^(3)/g,1.46)at 298 K and 1 bar.Grand Canonical Monte Carlo(GCMC)calculations indicate that C_(2)H_(6) has a stronger interaction with the ZIF-78-Co framework.Breakthrough experiments for the C_(2)H_(6)/C_(2)H_(4)(50:50,V/V)mixture at 298 K and 1 bar demonstrate that ZIF-78-Co achieves separation in approximately 5 min/g,outperforming ZIF-78-Zn.And the separation time for ZIF-78-Co in the C_(2)H_(6)/C_(2)H_(4)(10:90,V/V)mixture is 9 min/g.Furthermore,ZIF-78-Co exhibits excellent structural stability,thermal stability,water stability,and acid-base stability.Therefore,it holds promising prospects for practical industrial separation.Additionally,we hope that our findings inspire further experimentation on alternative metal ethane adsorbents.展开更多
We give a characterization of structurally stable diffeomorphisms by making use of the notion of LP-shadowing property. More precisely, we prove that the set of structurally stable diffeomorphisms coincides with the C...We give a characterization of structurally stable diffeomorphisms by making use of the notion of LP-shadowing property. More precisely, we prove that the set of structurally stable diffeomorphisms coincides with the C1-interior of the set of diffeomorphisms having LP-shadowing property.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.52072196,52002200,52102106,52202262,22379081,and 22379080Major Basic Research Program of the Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09+1 种基金the Natural Science Foundation of Shandong Province under Grant No.ZR2020QE063,ZR202108180009,ZR2023QE059the Postdoctoral Program in Qingdao under No.QDBSH20220202019。
文摘Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10574036 and 10574037). and the Hebei Natural Science Foundation (Grant Nos A2004000141 and 2005000143).
文摘The structural stability and magnetic properties of the icosahedral Ni13, Ni13^+1 and Ni13^-1 clusters have been obtained by utilizing all-electron density functional theory with the generalized gradient approximations for the exchange-correlation energy. The calculated results show that the ground states of neutral and charged clusters all favour a D3d structure, a distorted icosahedron, due to the Jahn-Teller effect. The radial distortions caused by doping one electron and by doping one hole are opposite to each other. Doping one electron will result in a 1/2 decrease and doping one hole will result in a 1/2 increase of the total spin. Both increasing interatomic spacing and decreasing coordination will lead to an enhancement of the spin magnetic moments for Nil3 clusters.
基金The National Marine Public Welfare Project of China under contract No.201305005
文摘The food sources of aquacultured Apostichopus japonicus and the trophic levels of organisms in a sea cucumber(A. japonicus) and prawn(Penaeus japonica) polyculture system in a saltwater pond in Zhuanghe, Liaoning Province were examined using carbon and nitrogen stable isotopes. Across organisms, δ13C ranged from(–25.47±0.20)‰ to(–16.48±0.17)‰(mean±SD), and δ15N ranged from(4.23±0.49)‰ to(12.44±0.09)‰. The δ13C and δ15N contents of A. japonicus, P. japonica and Fenneropenaeus chinensis were comparatively higher than those of other organisms. Values of δ13C and δ15N revealed that P. japonica, Hemigrapsus sanguineus and Neomysis japonica comprised the largest component of the diet of A. japonicus. The mean trophic level of the organisms in this saltwater pond polyculture system was(2.75±0.08). P. japonica, A. japonicus, F. chinensis,Synechogobius hasta and Neomysis japonica were in the 3rd trophic level(2–3); jellyfish, H. sanguineus and zooplankton were in the 2nd trophic level(1–2); and Enteromorpha prolifera, benthic microalgae, periphyton and suspended matter primarily consisting of phytoplankton, bacteria and humus were in the primary trophic level(0–1).
基金supported by the National Natural Science Foundation of China(Grant Nos.11474234 and 61403318)the Fundamental Research Funds for the Central Universities of China(Grant No.20720160085)
文摘Due to the dependence of the chemical and physical properties of the bimetallic nanoparticles(NPs) on their structures,a fundamental understanding of their structural characteristics is crucial for their syntheses and wide applications. In this article, a systematical atomic-level investigation of Au–Pd bimetallic NPs is conducted by using the improved particle swarm optimization(IPSO) with quantum correction Sutton–Chen potentials(Q-SC) at different Au/Pd ratios and different sizes. In the IPSO, the simulated annealing is introduced into the classical particle swarm optimization(PSO) to improve the effectiveness and reliability. In addition, the influences of initial structure, particle size and composition on structural stability and structural features are also studied. The simulation results reveal that the initial structures have little effects on the stable structures, but influence the converging rate greatly, and the convergence rate of the mixing initial structure is clearly faster than those of the core-shell and phase structures. We find that the Au–Pd NPs prefer the structures with Au-rich in the outer layers while Pd-rich in the inner ones. Especially, when the Au/Pd ratio is 6:4, the structure of the nanoparticle(NP) presents a standardized Pd(core) Au(shell) structure.
文摘A dpoamic deecription of the marked disparity in economic developmentbetween China' s Middle-West Resion and Along-Coast Resion is presented.Some qualitative investigation is siven to the expected prospects of the Middle-West Resion with some preliminary stratesic suggestions proposed.
基金Supported by National Natural Science Fundation of China(50674045)
文摘Similar material simulation test W9-15 101 fully mechanized caving face with was carried out in a geological model of large mining height in the Liuhuanggou Colliery, in Xinjiang Uigur Autonomous Region. The roof overlying strata movement law in the stope of a fully mechanized caving face with large mining height was studied and show that the roof overlying strata in the stope of a fully mechanized caving face with large mining height can be formed into a stable arch structure; the fracture rock beam is formed resembling a "bond beam", but it has essentially the structure of "multi-span beams" under the big structure of the stable arch. The roof overlying strata movement law in the stope of a fully mechanized caving face with large mining height is similar to that of the common, fully mechanized caving stope, which is determined by the deformation and instability of the structure of "multi-span beams". But because of the differences between the mining heights, the peak pressure in the stope of a fully mechanized caving face with large mining height is smaller while the affected area of abutment pressure is wider in the front of the working face; this is the obvious difference in abutment pressure between the stope of a fully mechanized caving face with large mining height and that of the common.
基金supported by the National Natural Science Foundation of China(Nos.60421002 and 60874098)the National High-Tech Research and Development Program(863)of China(No.2007AA042103)
文摘Obtaining an electrocorticograms(ECoG)signal requires an invasive procedure in which brain activity is recorded from the cortical surface.In contrast,obtaining electroencephalograms(EEG)recordings requires the non-invasive procedure of recording the brain activity from the scalp surface,which allows EEG recordings to be performed more easily on healthy humans.In this work,a technique previously used to study spatial-temporal patterns of brain activity on animal ECoG was adapted for use on EEG.The main issues are centered on solving the problems introduced by the increment on the interelectrode distance and the procedure to detect stable frames.The results showed that spatial patterns of beta and gamma activity can also be extracted from the EEG signal by using stable frames as time markers for feature extraction.This adapted technique makes it possible to take advantage of the cognitive and phenomenological awareness of a normal healthy subject.
文摘The elTcct of different dimension stabilization treatments on the dimension stability of SiC_(p)/Al composites were investigated by the measurement of microyield strength,microcreep properties,dimension,residual stress and analyses of transmission electron microscopy.Results show that the heat cycle dimension stabilization techniques could efficiently decrease the residual stress,stabilize the dimension change,and increase resistance to microplastic deformation.The main reason was that the heat cycle dimension stabilization techniques might form stable dislocation structure in the SiC_(p)/A1 composites.
基金supported by the National Key R&D Program of China(2022YFB3806800)the National Natural Science Foundation of China(22278288,22278287)the research project supported by the Shanxi Scholarship Council of China(2021-053).
文摘The acquisition of polymer-grade(≥99.95%)C_(2)H_(4) poses a challenge due to the presence of ethane(C_(2)H_(6))having similar physical and chemical properties.Consequently,the one-step purification of C_(2)H_(4) becomes a crucial and demanding process.In this study,we synthesized ZIF-78 with a GME configuration using different metal sources(Zn,Co).Both substances have been identified as ethane-selective adsorbents with excellent thermal stability.The Brunauer Emmett Teller(BET)surface area of ZIF-78-Co(748 m^(2)/g)surpasses that of ZIF-78-Zn(585 m^(2)/g),and the former exhibits a higher Q_(st) value for C_(2)H_(6),resulting in enhanced adsorption capacity for C_(2)H_(6)(50.61 cm^(3)/g)and selectivity for C_(2)H_(6)/C_(2)H_(4)(1.71)compared to ZIF-78-Zn(48.97 cm^(3)/g,1.46)at 298 K and 1 bar.Grand Canonical Monte Carlo(GCMC)calculations indicate that C_(2)H_(6) has a stronger interaction with the ZIF-78-Co framework.Breakthrough experiments for the C_(2)H_(6)/C_(2)H_(4)(50:50,V/V)mixture at 298 K and 1 bar demonstrate that ZIF-78-Co achieves separation in approximately 5 min/g,outperforming ZIF-78-Zn.And the separation time for ZIF-78-Co in the C_(2)H_(6)/C_(2)H_(4)(10:90,V/V)mixture is 9 min/g.Furthermore,ZIF-78-Co exhibits excellent structural stability,thermal stability,water stability,and acid-base stability.Therefore,it holds promising prospects for practical industrial separation.Additionally,we hope that our findings inspire further experimentation on alternative metal ethane adsorbents.
文摘We give a characterization of structurally stable diffeomorphisms by making use of the notion of LP-shadowing property. More precisely, we prove that the set of structurally stable diffeomorphisms coincides with the C1-interior of the set of diffeomorphisms having LP-shadowing property.