Pedestrian self-organizing movement plays a significant role in evacuation studies and architectural design.Lane formation,a typical self-organizing phenomenon,helps pedestrian system to become more orderly,the majori...Pedestrian self-organizing movement plays a significant role in evacuation studies and architectural design.Lane formation,a typical self-organizing phenomenon,helps pedestrian system to become more orderly,the majority of following behavior model and overtaking behavior model are imprecise and unrealistic compared with pedestrian movement in the real world.In this study,a pedestrian dynamic model considering detailed modelling of the following behavior and overtaking behavior is constructed,and a method of measuring the lane formation and pedestrian system order based on information entropy is proposed.Simulation and analysis demonstrate that the following and avoidance behaviors are important factors of lane formation.A high tendency of following results in good lane formation.Both non-selective following behavior and aggressive overtaking behavior cause the system order to decrease.The most orderly following strategy for a pedestrian is to overtake the former pedestrian whose speed is lower than approximately 70%of his own.The influence of the obstacle layout on pedestrian lane and egress efficiency is also studied with this model.The presence of a small obstacle does not obstruct the walking of pedestrians;in contrast,it may help to improve the egress efficiency by guiding the pedestrian flow and mitigating the reduction of pedestrian system orderliness.展开更多
In recent years,distributed photovoltaics(DPV)has ushered in a good development situation due to the advantages of pollution-free power generation,full utilization of the ground or roof of the installation site,and ba...In recent years,distributed photovoltaics(DPV)has ushered in a good development situation due to the advantages of pollution-free power generation,full utilization of the ground or roof of the installation site,and balancing a large number of loads nearby.However,under the background of a large-scale DPV grid-connected to the county distribution network,an effective analysis method is needed to analyze its impact on the voltage of the distribution network in the early development stage of DPV.Therefore,a DPV orderly grid-connected method based on photovoltaics grid-connected order degree(PGOD)is proposed.This method aims to orderly analyze the change of voltage in the distribution network when large-scale DPV will be connected.Firstly,based on the voltagemagnitude sensitivity(VMS)index of the photovoltaics permitted grid-connected node and the acceptance of grid-connected node(AoGCN)index of other nodes in the network,thePGODindex is constructed to determine the photovoltaics permitted grid-connected node of the current photovoltaics grid-connected state network.Secondly,a photovoltaics orderly grid-connected model with a continuous updating state is constructed to obtain an orderly DPV grid-connected order.The simulation results illustrate that the photovoltaics grid-connected order determined by this method based on PGOD can effectively analyze the voltage impact of large-scale photovoltaics grid-connected,and explore the internal factors and characteristics of the impact.展开更多
Given a vertex v of a graph G the second order degree of v denoted as d2(v) is defined as the number of vertices at distance 2 from v. In this paper we address the following question: What axe the sufficient condit...Given a vertex v of a graph G the second order degree of v denoted as d2(v) is defined as the number of vertices at distance 2 from v. In this paper we address the following question: What axe the sufficient conditions for a graph to have a vertex v such that d2(v) ≥ d(v), where d(v) denotes the degree of v? Among other results, every graph of minimum degree exactly 2, except four graphs, is shown to have a vertex of second order degree as large as its own degree. Moreover, every K4^--free graph or every maximal planar graph is shown to have a vertex v such that d2(v) ≥ d(v). Other sufficient conditions on graphs for guaranteeing this property axe also proved.展开更多
FeSiAl alloys ribbons synthesized by melt-quench were annealed in vacuum at 873 K for 60 rain. The flaky powders were prepared by milling the annealed ribbons for 70 h. After milling, the powders were heat treated at ...FeSiAl alloys ribbons synthesized by melt-quench were annealed in vacuum at 873 K for 60 rain. The flaky powders were prepared by milling the annealed ribbons for 70 h. After milling, the powders were heat treated at 573 K for 90 rain. The ordering degree of the powders lattice structure was analyzed by X-ray diffraction (XRD). The measurement of specific saturation magnetization was carried out by vibrating samples magnetometer (VSM). Complex permittivity and complex permeability in the frequency band of 0.5-18 GHz were measured with the vector network analyzer. The ordering degree of the superlattice structure increased from 0.2'7 to 0.49. Complex permittivity and complex permeability decreased with increasing Si content. After ordering, the specific saturation magnetization decreased from 134.2 to 85.0 A.m2.kg-1. For use in anti-EMI material, the total contents of Si and Al in FeSiAl alloys should be controlled at a low level.展开更多
The influence of grain size and ordering degree of the parent phase on the shape memory re- covery in a Cu-25.62Zn-3.97Al-0.0018B(wt-%)memory alloy is investigated.A mathematical relationship is set up between the rec...The influence of grain size and ordering degree of the parent phase on the shape memory re- covery in a Cu-25.62Zn-3.97Al-0.0018B(wt-%)memory alloy is investigated.A mathematical relationship is set up between the recovery ratio and ordering degree,probabili- ty of atoms at their ordered sites,grain size,the thickness of the grain boundary affected re- gions,the stress during deformation,as well as the critical shear stress.Shape memory effect reaches a maximum with varying grain size and increases linearly with increasing ordering parameter,which agrees well with experimental results.展开更多
This paper derives the expressions for the ordering degree and the modulation factor of A and B atoms in AXB1-xC epilayers of ternary III-V semiconductor alloys. Using these expressions, it identifies quantitatively t...This paper derives the expressions for the ordering degree and the modulation factor of A and B atoms in AXB1-xC epilayers of ternary III-V semiconductor alloys. Using these expressions, it identifies quantitatively the alternating atom-enhanced planes, compositional modulations, atomic ordering degree on the group-III sublattices and the fine structure of NMR spectra.展开更多
The temperature-dependent Gilbert damping in Co2FeAl thin film grown on a Pb(Mg1/3Nb2/3)O3-30%PbTiO3 substrate is investigated by the systematic measurement of physical property measurement system(PPMS) on a series of...The temperature-dependent Gilbert damping in Co2FeAl thin film grown on a Pb(Mg1/3Nb2/3)O3-30%PbTiO3 substrate is investigated by the systematic measurement of physical property measurement system(PPMS) on a series of samples with different substrate temperatures. Varying the substrate temperatures from 350℃ to 500℃, the B2 ordering degrees of Co2FeAl thin films increase, which can lead the Gilbert damping to decrease, indicated by the field-sweep in-plane PPMS measurements. In addition, the measurement result of PPMS demonstrates that the Gilbert damping decreases first with measurement temperature decreasing down to about 150 K, then increases at a measurement temperature of ~ 50 K, and decreases again with the measurement temperature decreasing. There are two independent damping manners, namely bulk damping and surface damping, which contribute to the Gilbert damping. Moreover, the observed peak of Gilbert damping at ~ 50 K can be attributed to the spin re-orientation transition at the Co2FeAl surface, which is similar to the result of the effective magnetization as a function of measurement temperature. The result presents the evidence for further studying the Gilbert damping in Co2FeAl thin film.展开更多
The degree of ordering and ordered domain size in solid solution AlNi3 prepared by SHS have been deter-mined -with XRD. The reszilts indicate that the greater the form-ing pressure on the raw materials , the higher th...The degree of ordering and ordered domain size in solid solution AlNi3 prepared by SHS have been deter-mined -with XRD. The reszilts indicate that the greater the form-ing pressure on the raw materials , the higher the degree of or-dering,the larger the ordered domain size.展开更多
It is a hot issue in communication research field to select the best network for Heterogeneous Wireless Networks(HWNs),and it is also a difficult problem to reduce the handoff number of vertical handoff.In order to so...It is a hot issue in communication research field to select the best network for Heterogeneous Wireless Networks(HWNs),and it is also a difficult problem to reduce the handoff number of vertical handoff.In order to solve this problem,the paper proposes a multiple attribute network selection algorithm based on Analytic Hierarchy Process(AHP)and synergetic theory.The algorithm applies synergetics to network selection,considering the candidate network as a compound system composed of multiple attribute subsystems,and combines the subsystem order degree with AHP weight to obtain entropy of the compound system,which is opposite the synergy degree of a network system.The greater the synergy degree,the better the network performance.The algorithm takes not only the coordination of objective attributes but also Quality of Service(QoS)requirements into consideration,ensuring that users select the network with overall good performance.The simulation results show that the proposed algorithm can effectively reduce the handoff number and provide uses with satisfactory QoS according to different services.展开更多
There are fractal character and fractal dimensions with time in crustal deformation field of seismogeny process.The occurrence of strong earthquake is after the process of the dimension lowering, entrolpy decreasing a...There are fractal character and fractal dimensions with time in crustal deformation field of seismogeny process.The occurrence of strong earthquake is after the process of the dimension lowering, entrolpy decreasing and ordering,the fractal dimension, entropy value and order degree are all resumed normal datum after the occurrence of strong earthquake, it reflects the evolution of crustal deformation field is the process from the homogeneous deformation - heterogeneous deformation - disturbance - homogeneous deformation. We regarded the fractal dimension, information entropy and order degree as pattern dynamics parameters of crustal deformation field to use, and the deformation localize process is quantitatively described by the parameters.展开更多
Palm kernel shell(PKS)biochars with different levels of carbon conversion were initially prepared using a tube furnace,after which the reactivity of each sample was assessed with a thermogravimetric analyzer under a C...Palm kernel shell(PKS)biochars with different levels of carbon conversion were initially prepared using a tube furnace,after which the reactivity of each sample was assessed with a thermogravimetric analyzer under a CO_2 atmosphere.The pore structure and carbon ordering of each biochar also examined,employing a surface area analyzer and a Raman spectroscopy.Thermogravimetric results showed that the gasification index R_sof the PKS biochar decreased from 0.0305 min^(-1) at carbon conversion(x)=20% to 0.0278 min^(-1)at x=40%.The expansion of micropores was the dominant process during the pore structure evolution,ad mesopores with sizes ranging from 6 to 20,48 to 50 nm were primarily generated during gasification under a CO_2/H_2O mixture.The proportion of amorphous carbon in the PKS biochar decreased significantly as x increased,suggesting that the proportion of ordered carbon was increased during the CO_2/H_2O mixed gasification.A significantly reduced total reaction time was observed when employing a CO_2/intermittent H_2O process along with an 83.46% reduction in the steam feed,compared with the amount required using a CO_2/H_2O atmosphere.展开更多
WS2 exhibits tremendous potentials for Na-ions storage owing to high capacity(433 mAh g^(-1)). Nevertheless, WS2 layered structure is often exfoliated with rapid capacity decay and sluggish reaction kinetics.In this w...WS2 exhibits tremendous potentials for Na-ions storage owing to high capacity(433 mAh g^(-1)). Nevertheless, WS2 layered structure is often exfoliated with rapid capacity decay and sluggish reaction kinetics.In this work, WS2 nanosheets with different crystallinities are controlled by different synthesis methods.The high crystallinity WS2 exhibits high degree of interlayer order and strong interlayer force. It exhibits superior electrochemical properties, at the current density of 200 mA g^(-1) after 300 cycles with reversible capacity of 471 mAh g^(-1). Even at 5.0 A g^(-1), the capacities can still arrive at 240 mAh g^(-1) after 250 cycles, exhibiting stable cycling performance. Further electrochemical research finds that the high degree of interlayer order of layered WS2 structure can perform highly conducive Na+insertion/extraction with greatly improved contribution of intercalation capacity. Moreover, the strong interlayer force can effectively restrain the exfoliating of the WS2 nanosheets, guaranteeing the stability of the structure. Combining the above result reveals that controlling the order and force of the interlayer is an effective way to enhance the electrochemical properties of WS2 as SIBs anode materials. This work can provide new insight for inhibiting the exfoliation of layered compounds to pursue excellent electrochemical performance in Na-ion storage systems.展开更多
The optimization model based on Markov chain is established to optimize the prediction of industrial structure and provide reference for policy adjustment.The vectorization operator is used to transform the Markov pre...The optimization model based on Markov chain is established to optimize the prediction of industrial structure and provide reference for policy adjustment.The vectorization operator is used to transform the Markov prediction model into an optimization problem with constraints,which highlights the theoretical proof and computational rigor.Based on the data of three industrial structures in Yunnan Province from 1989 to 2019,this paper establishes Markov optimization model to predict the proportion of three industrial structures in Yunnan Province from 2020 to 2030.The maximum percentage average absolute error and hill inequality coefficient of the prediction are 1.2335%and 0.2,respectively.The order-degree of the three industrial structures is a stable series,which is stable around 1 after 1996.The sample data and the predicted values show four stages of change characteristics.After 2020,the three industrial structures are stable in the"three,two and one"structure.展开更多
The effects of Dy on the microstructure and magnetic properties of DyxCo50-xPt50 alloys were investigated. The XRD results indicate that all the alloys homogenized at 1000 ℃ contain only a single A 1 (fcc) phase, w...The effects of Dy on the microstructure and magnetic properties of DyxCo50-xPt50 alloys were investigated. The XRD results indicate that all the alloys homogenized at 1000 ℃ contain only a single A 1 (fcc) phase, while the alloys annealed at 675℃ consist of a hard-magnetic face-eentered-tetragonal (fct) phase and a magnetically soft face-centered-cube (fcc) phase. Maximum values for the coercivity and remanence ratio mr were achieved in DY0.4Co49.6Pt50 alloys annealed at 675 ℃ for 80 min. For the series of Dy Co50-xPt50 alloys annealed at 675 ℃ for 60 min, H decreases monotonically with increasing Dy concentration, but mr is first enhanced and then weakened,展开更多
Effects of the content of Dy on structure and magnetic properties of DyxFe60.5-xPt39.5 alloys(x = 0, 0.5, 1.0, 1.5) were investigated. The results of XRD analysis proved that the phase-transitional temperature of Dy...Effects of the content of Dy on structure and magnetic properties of DyxFe60.5-xPt39.5 alloys(x = 0, 0.5, 1.0, 1.5) were investigated. The results of XRD analysis proved that the phase-transitional temperature of DyxFe60.5-xPt39.5 alloys from disordered face-centered-cubic structure to ordered face-centered-tetragonal cubic structure decreases with the increase of the content of Dy(x). Suitable content of Dy can improve the exchange coupling between soft magnetic phase and hard magnetic phase by refining grain size, while the remanence ratio and coercivity of the Fe60.5Pt39.5 alloy can be significantly improved by a small replacement of Fe by Dy, good magnetic properties were obtained in Dy0.5Fe60.0Pt39.5 alloys.展开更多
The nanocrystalline structure of annealed Fe73.5 Cu1 W3Si13.5B9 alloy has been investigated by using the XRD and the TEM methods. The relation between the initial permeability and the microstructure of the annealed al...The nanocrystalline structure of annealed Fe73.5 Cu1 W3Si13.5B9 alloy has been investigated by using the XRD and the TEM methods. The relation between the initial permeability and the microstructure of the annealed alloy has been discussed. The crystalline phase in annealed Fe73.5 Cu1 W3Si13.5B9 alloy is the α-Fe(Si) phase with DO3 superstructure. The volume fraction, Si content and degree of order of the αFe(Si) phase increase with increasing annealing temperature. In the temperature range of 490-570℃, the α-Fe(Si) phase has a size of 13 nm, and its grain number increases as the annealing temperature is increased. The DO3 ordered region in the α-Fe(Si) grain is spherical approximately, and its size increases as the annealing temperature increases. The size of the DO3 ordered region is 12.8 nm at the temperature of 570℃,which is close to that of the α-Fe(Si) grain. There is obvious change in the structure of the residual amorphous phase during annealing, and the nearest atomic distance and the short-range order of residual amorphous phase reach maximum and minimum at 530℃, respectively. The initial permeability of annealed Fe73.5 Cu1 W3Si13.5 B9 alloy is not only dependent on the size, volume fraction and Si content of the α-Fe(Si) phase but also related to the structure state of the residual amorphous phase.展开更多
Two sets of La_(2)NiMnO_(6)ceramics with different B-site ordering degree were prepared and evaluated.The valence states of Ni^(2+)and Mn^(4+)were con-rmed,and the B-site ordering degree was estimated qualitatively us...Two sets of La_(2)NiMnO_(6)ceramics with different B-site ordering degree were prepared and evaluated.The valence states of Ni^(2+)and Mn^(4+)were con-rmed,and the B-site ordering degree was estimated qualitatively using magnetic and Raman analysis.The ordering of Ni^(2+)and Mn^(4+)was the primary origin for the relaxor-like behavior of the present ceramics.The ordering degree of B-site ions greatly affected the dielectric properties,i.e.,more ordered sample indicated higher dielectric constant.Meanwhile,the grain boundary layer capacitor(GBLC)effect was also activated but limited at the high temperatures and low frequencies.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.71603146).
文摘Pedestrian self-organizing movement plays a significant role in evacuation studies and architectural design.Lane formation,a typical self-organizing phenomenon,helps pedestrian system to become more orderly,the majority of following behavior model and overtaking behavior model are imprecise and unrealistic compared with pedestrian movement in the real world.In this study,a pedestrian dynamic model considering detailed modelling of the following behavior and overtaking behavior is constructed,and a method of measuring the lane formation and pedestrian system order based on information entropy is proposed.Simulation and analysis demonstrate that the following and avoidance behaviors are important factors of lane formation.A high tendency of following results in good lane formation.Both non-selective following behavior and aggressive overtaking behavior cause the system order to decrease.The most orderly following strategy for a pedestrian is to overtake the former pedestrian whose speed is lower than approximately 70%of his own.The influence of the obstacle layout on pedestrian lane and egress efficiency is also studied with this model.The presence of a small obstacle does not obstruct the walking of pedestrians;in contrast,it may help to improve the egress efficiency by guiding the pedestrian flow and mitigating the reduction of pedestrian system orderliness.
基金supported by North China Electric Power Research Institute’s Self-Funded Science and Technology Project“Research on Distributed Energy Storage Optimal Configuration and Operation Control Technology for Photovoltaic Promotion in the Entire County”(KJZ2022049).
文摘In recent years,distributed photovoltaics(DPV)has ushered in a good development situation due to the advantages of pollution-free power generation,full utilization of the ground or roof of the installation site,and balancing a large number of loads nearby.However,under the background of a large-scale DPV grid-connected to the county distribution network,an effective analysis method is needed to analyze its impact on the voltage of the distribution network in the early development stage of DPV.Therefore,a DPV orderly grid-connected method based on photovoltaics grid-connected order degree(PGOD)is proposed.This method aims to orderly analyze the change of voltage in the distribution network when large-scale DPV will be connected.Firstly,based on the voltagemagnitude sensitivity(VMS)index of the photovoltaics permitted grid-connected node and the acceptance of grid-connected node(AoGCN)index of other nodes in the network,thePGODindex is constructed to determine the photovoltaics permitted grid-connected node of the current photovoltaics grid-connected state network.Secondly,a photovoltaics orderly grid-connected model with a continuous updating state is constructed to obtain an orderly DPV grid-connected order.The simulation results illustrate that the photovoltaics grid-connected order determined by this method based on PGOD can effectively analyze the voltage impact of large-scale photovoltaics grid-connected,and explore the internal factors and characteristics of the impact.
基金Supported by the Ministry of Education and Science,Spainthe European Regional Development Fund (ERDF)under project MTM2008-06620-C03-02+2 种基金the Catalan Government under project 2009 SGR 1298CONACyTMxico under project 57371PAPIIT-UNAM IN104609-3
文摘Given a vertex v of a graph G the second order degree of v denoted as d2(v) is defined as the number of vertices at distance 2 from v. In this paper we address the following question: What axe the sufficient conditions for a graph to have a vertex v such that d2(v) ≥ d(v), where d(v) denotes the degree of v? Among other results, every graph of minimum degree exactly 2, except four graphs, is shown to have a vertex of second order degree as large as its own degree. Moreover, every K4^--free graph or every maximal planar graph is shown to have a vertex v such that d2(v) ≥ d(v). Other sufficient conditions on graphs for guaranteeing this property axe also proved.
文摘FeSiAl alloys ribbons synthesized by melt-quench were annealed in vacuum at 873 K for 60 rain. The flaky powders were prepared by milling the annealed ribbons for 70 h. After milling, the powders were heat treated at 573 K for 90 rain. The ordering degree of the powders lattice structure was analyzed by X-ray diffraction (XRD). The measurement of specific saturation magnetization was carried out by vibrating samples magnetometer (VSM). Complex permittivity and complex permeability in the frequency band of 0.5-18 GHz were measured with the vector network analyzer. The ordering degree of the superlattice structure increased from 0.2'7 to 0.49. Complex permittivity and complex permeability decreased with increasing Si content. After ordering, the specific saturation magnetization decreased from 134.2 to 85.0 A.m2.kg-1. For use in anti-EMI material, the total contents of Si and Al in FeSiAl alloys should be controlled at a low level.
文摘The influence of grain size and ordering degree of the parent phase on the shape memory re- covery in a Cu-25.62Zn-3.97Al-0.0018B(wt-%)memory alloy is investigated.A mathematical relationship is set up between the recovery ratio and ordering degree,probabili- ty of atoms at their ordered sites,grain size,the thickness of the grain boundary affected re- gions,the stress during deformation,as well as the critical shear stress.Shape memory effect reaches a maximum with varying grain size and increases linearly with increasing ordering parameter,which agrees well with experimental results.
基金Project supported by the National Natural Science Foundation of China (Grant No 60572177)CAUC Foundation (Grant No 05yk27s)
文摘This paper derives the expressions for the ordering degree and the modulation factor of A and B atoms in AXB1-xC epilayers of ternary III-V semiconductor alloys. Using these expressions, it identifies quantitatively the alternating atom-enhanced planes, compositional modulations, atomic ordering degree on the group-III sublattices and the fine structure of NMR spectra.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51671099,11974149,and 51901163)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT-16R35).
文摘The temperature-dependent Gilbert damping in Co2FeAl thin film grown on a Pb(Mg1/3Nb2/3)O3-30%PbTiO3 substrate is investigated by the systematic measurement of physical property measurement system(PPMS) on a series of samples with different substrate temperatures. Varying the substrate temperatures from 350℃ to 500℃, the B2 ordering degrees of Co2FeAl thin films increase, which can lead the Gilbert damping to decrease, indicated by the field-sweep in-plane PPMS measurements. In addition, the measurement result of PPMS demonstrates that the Gilbert damping decreases first with measurement temperature decreasing down to about 150 K, then increases at a measurement temperature of ~ 50 K, and decreases again with the measurement temperature decreasing. There are two independent damping manners, namely bulk damping and surface damping, which contribute to the Gilbert damping. Moreover, the observed peak of Gilbert damping at ~ 50 K can be attributed to the spin re-orientation transition at the Co2FeAl surface, which is similar to the result of the effective magnetization as a function of measurement temperature. The result presents the evidence for further studying the Gilbert damping in Co2FeAl thin film.
文摘The degree of ordering and ordered domain size in solid solution AlNi3 prepared by SHS have been deter-mined -with XRD. The reszilts indicate that the greater the form-ing pressure on the raw materials , the higher the degree of or-dering,the larger the ordered domain size.
基金Supported by the Major State Basic Research Development Program of China(973 Program)(No.2013CB329005)the National Natural Science Foundation of China(No.61171094)+1 种基金the National Science & Technology Key Project(No.2011ZX03001-006-02.No.2011ZX03005004-03)the Key Project of Jiangsu Provincial Natural Science Foundation(No.BK2011027)
文摘It is a hot issue in communication research field to select the best network for Heterogeneous Wireless Networks(HWNs),and it is also a difficult problem to reduce the handoff number of vertical handoff.In order to solve this problem,the paper proposes a multiple attribute network selection algorithm based on Analytic Hierarchy Process(AHP)and synergetic theory.The algorithm applies synergetics to network selection,considering the candidate network as a compound system composed of multiple attribute subsystems,and combines the subsystem order degree with AHP weight to obtain entropy of the compound system,which is opposite the synergy degree of a network system.The greater the synergy degree,the better the network performance.The algorithm takes not only the coordination of objective attributes but also Quality of Service(QoS)requirements into consideration,ensuring that users select the network with overall good performance.The simulation results show that the proposed algorithm can effectively reduce the handoff number and provide uses with satisfactory QoS according to different services.
文摘There are fractal character and fractal dimensions with time in crustal deformation field of seismogeny process.The occurrence of strong earthquake is after the process of the dimension lowering, entrolpy decreasing and ordering,the fractal dimension, entropy value and order degree are all resumed normal datum after the occurrence of strong earthquake, it reflects the evolution of crustal deformation field is the process from the homogeneous deformation - heterogeneous deformation - disturbance - homogeneous deformation. We regarded the fractal dimension, information entropy and order degree as pattern dynamics parameters of crustal deformation field to use, and the deformation localize process is quantitatively described by the parameters.
基金Supported by the Key Project of the Natural Science Foundation of Shandong Province(ZR2015QZ02)the Key Research&Development Program of Shandong Province(2016GSF117005)+1 种基金the introduction of scientific and technological innovation team of Ningxia Hui Autonomous Region(2016)Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(2017-K22)
文摘Palm kernel shell(PKS)biochars with different levels of carbon conversion were initially prepared using a tube furnace,after which the reactivity of each sample was assessed with a thermogravimetric analyzer under a CO_2 atmosphere.The pore structure and carbon ordering of each biochar also examined,employing a surface area analyzer and a Raman spectroscopy.Thermogravimetric results showed that the gasification index R_sof the PKS biochar decreased from 0.0305 min^(-1) at carbon conversion(x)=20% to 0.0278 min^(-1)at x=40%.The expansion of micropores was the dominant process during the pore structure evolution,ad mesopores with sizes ranging from 6 to 20,48 to 50 nm were primarily generated during gasification under a CO_2/H_2O mixture.The proportion of amorphous carbon in the PKS biochar decreased significantly as x increased,suggesting that the proportion of ordered carbon was increased during the CO_2/H_2O mixed gasification.A significantly reduced total reaction time was observed when employing a CO_2/intermittent H_2O process along with an 83.46% reduction in the steam feed,compared with the amount required using a CO_2/H_2O atmosphere.
基金supported by the National Natural Science Foundation of China (Nos. 21701107, 51672165, and 51472152)the China Postdoctoral Science Foundation (No. 2016M592897XB)+3 种基金Technology and Natural Science Foundation of Shaanxi (No. 2018JQ5107)Key Program for International S&T Cooperation Projects of Shaanxi ProvinceXi’an Key Laboratory of green manufacture of ceramic materials Foundation No. 2019220214SYS017CG039China Graduate Innovation Fund of Shaanxi University of Science and Technology。
文摘WS2 exhibits tremendous potentials for Na-ions storage owing to high capacity(433 mAh g^(-1)). Nevertheless, WS2 layered structure is often exfoliated with rapid capacity decay and sluggish reaction kinetics.In this work, WS2 nanosheets with different crystallinities are controlled by different synthesis methods.The high crystallinity WS2 exhibits high degree of interlayer order and strong interlayer force. It exhibits superior electrochemical properties, at the current density of 200 mA g^(-1) after 300 cycles with reversible capacity of 471 mAh g^(-1). Even at 5.0 A g^(-1), the capacities can still arrive at 240 mAh g^(-1) after 250 cycles, exhibiting stable cycling performance. Further electrochemical research finds that the high degree of interlayer order of layered WS2 structure can perform highly conducive Na+insertion/extraction with greatly improved contribution of intercalation capacity. Moreover, the strong interlayer force can effectively restrain the exfoliating of the WS2 nanosheets, guaranteeing the stability of the structure. Combining the above result reveals that controlling the order and force of the interlayer is an effective way to enhance the electrochemical properties of WS2 as SIBs anode materials. This work can provide new insight for inhibiting the exfoliation of layered compounds to pursue excellent electrochemical performance in Na-ion storage systems.
基金This research was funded by“Analysis of the Influence Mechanism of Modern Service Industry in Yunnan Province Based on Bayes Method”on the Project of Yunnan University Joint Fund(2017FH001-068).
文摘The optimization model based on Markov chain is established to optimize the prediction of industrial structure and provide reference for policy adjustment.The vectorization operator is used to transform the Markov prediction model into an optimization problem with constraints,which highlights the theoretical proof and computational rigor.Based on the data of three industrial structures in Yunnan Province from 1989 to 2019,this paper establishes Markov optimization model to predict the proportion of three industrial structures in Yunnan Province from 2020 to 2030.The maximum percentage average absolute error and hill inequality coefficient of the prediction are 1.2335%and 0.2,respectively.The order-degree of the three industrial structures is a stable series,which is stable around 1 after 1996.The sample data and the predicted values show four stages of change characteristics.After 2020,the three industrial structures are stable in the"three,two and one"structure.
基金Funded by the National Natural Science Foundation of China(No.51261004&50661002)the National Science foundation of Guangxi Province(2012GXNSFGA060002)
文摘The effects of Dy on the microstructure and magnetic properties of DyxCo50-xPt50 alloys were investigated. The XRD results indicate that all the alloys homogenized at 1000 ℃ contain only a single A 1 (fcc) phase, while the alloys annealed at 675℃ consist of a hard-magnetic face-eentered-tetragonal (fct) phase and a magnetically soft face-centered-cube (fcc) phase. Maximum values for the coercivity and remanence ratio mr were achieved in DY0.4Co49.6Pt50 alloys annealed at 675 ℃ for 80 min. For the series of Dy Co50-xPt50 alloys annealed at 675 ℃ for 60 min, H decreases monotonically with increasing Dy concentration, but mr is first enhanced and then weakened,
基金Funded by the National Natural Science Foundation of China(No.50261002&50661002)
文摘Effects of the content of Dy on structure and magnetic properties of DyxFe60.5-xPt39.5 alloys(x = 0, 0.5, 1.0, 1.5) were investigated. The results of XRD analysis proved that the phase-transitional temperature of DyxFe60.5-xPt39.5 alloys from disordered face-centered-cubic structure to ordered face-centered-tetragonal cubic structure decreases with the increase of the content of Dy(x). Suitable content of Dy can improve the exchange coupling between soft magnetic phase and hard magnetic phase by refining grain size, while the remanence ratio and coercivity of the Fe60.5Pt39.5 alloy can be significantly improved by a small replacement of Fe by Dy, good magnetic properties were obtained in Dy0.5Fe60.0Pt39.5 alloys.
文摘The nanocrystalline structure of annealed Fe73.5 Cu1 W3Si13.5B9 alloy has been investigated by using the XRD and the TEM methods. The relation between the initial permeability and the microstructure of the annealed alloy has been discussed. The crystalline phase in annealed Fe73.5 Cu1 W3Si13.5B9 alloy is the α-Fe(Si) phase with DO3 superstructure. The volume fraction, Si content and degree of order of the αFe(Si) phase increase with increasing annealing temperature. In the temperature range of 490-570℃, the α-Fe(Si) phase has a size of 13 nm, and its grain number increases as the annealing temperature is increased. The DO3 ordered region in the α-Fe(Si) grain is spherical approximately, and its size increases as the annealing temperature increases. The size of the DO3 ordered region is 12.8 nm at the temperature of 570℃,which is close to that of the α-Fe(Si) grain. There is obvious change in the structure of the residual amorphous phase during annealing, and the nearest atomic distance and the short-range order of residual amorphous phase reach maximum and minimum at 530℃, respectively. The initial permeability of annealed Fe73.5 Cu1 W3Si13.5 B9 alloy is not only dependent on the size, volume fraction and Si content of the α-Fe(Si) phase but also related to the structure state of the residual amorphous phase.
基金supported by National Sci-ence Foundation of China under Grant numbers 50832005 and 50702049.
文摘Two sets of La_(2)NiMnO_(6)ceramics with different B-site ordering degree were prepared and evaluated.The valence states of Ni^(2+)and Mn^(4+)were con-rmed,and the B-site ordering degree was estimated qualitatively using magnetic and Raman analysis.The ordering of Ni^(2+)and Mn^(4+)was the primary origin for the relaxor-like behavior of the present ceramics.The ordering degree of B-site ions greatly affected the dielectric properties,i.e.,more ordered sample indicated higher dielectric constant.Meanwhile,the grain boundary layer capacitor(GBLC)effect was also activated but limited at the high temperatures and low frequencies.