From the perspective of facilitating the design of fluidized hydrogen reduction reactors for iron ore powder and maintaining stable operation,the operational conditions and bubble behavior in stable state fluidization...From the perspective of facilitating the design of fluidized hydrogen reduction reactors for iron ore powder and maintaining stable operation,the operational conditions and bubble behavior in stable state fluidization of multi-particle size systems were investigated through cold-state experiments.To facilitate the identification of bubble behavior,a two-dimensional bubbling bed cold-state experiment was carried out using iron ore powder with a narrow particle size distribution and glass beads.Initially,the multi-stage fluidization characteristics of iron ore powder were examined.Then,using Geldart B-type glass beads to simulate a multi-particle size composition system,the particle size range and superficial gas velocity range for stable operation of the multi-particle composition system were explored.When the mass percentage of 150-μm glass beads was 15%,the stable fluidization operational gas velocity range was found to be(1.05-1.21)umf,where umf is the minimum fluidization velocity;when the content was 20%,the stable fluidized superficial gas velocity range was(1.09-1.26)umf.Under stable fluidization operating conditions,the dynamic behavior of bubbles(average equivalent diameter,rising velocity,and lateral migration velocity)was studied,and the quantitative relationship between the average equivalent diameter of bubbles and bed height in multi-particle size systems under stable fluidization conditions was also corrected.Additionally,the correlation between bubble rising velocity and bubble average equivalent diameter was established.展开更多
A ring R is said to be satisfying P-stable range provided that whenever aR ＋ bR = R, there exists y ∈ P（R） such that a ＋ by is a unit of R, where P（R） is the subset of R which satisfies the property that up, pu...A ring R is said to be satisfying P-stable range provided that whenever aR ＋ bR = R, there exists y ∈ P（R） such that a ＋ by is a unit of R, where P（R） is the subset of R which satisfies the property that up, pu∈ P（R） for every unit u of R and p ∈P（R）. By studying this ring, some known results of rings satisfying unit-1 stable range, （ S, 2） -stable range, weakly unit 1- stable range and stable range one are unified. An element of a ring is said to be UR if it is the sum of a unit and a regular dement and a ring is said to be satisfying UR-stable range if R has P-stable range and P（R） is the set of all UR-elements of R, Some properties of this ring are studied and it is proven that if R satisfies UR-stahle range then so does any n × n matrix ring over R.展开更多
In this paper we study the formal triangular matrix ring T =and give some necessary and sufficient conditions for T to be (strongly) separative, m-fold stable and unit 1-stable. Moreover, a condition for finitely gene...In this paper we study the formal triangular matrix ring T =and give some necessary and sufficient conditions for T to be (strongly) separative, m-fold stable and unit 1-stable. Moreover, a condition for finitely generated projec-tive T-modules to have n in the stable range is given under the assumption that A and B are exchange rings.展开更多
Based on the optimal velocity models, an extended model is proposed, in which multi-veloclty-dllterence aheacl is taken into consideration. The damping effect of the multi-velocity-difference ahead has been investigat...Based on the optimal velocity models, an extended model is proposed, in which multi-veloclty-dllterence aheacl is taken into consideration. The damping effect of the multi-velocity-difference ahead has been investigated by means of analytical and numerical methods. Results indicate that the multi-velocity-difference leads to the enhancement of stability of traffic flow, suppression of the emergence of traffic jamming, and reduction of the energy consumption.展开更多
According to Ihe combinations of mctallogcnetic elements and minerals assemblages,the Au-Ag deposits in the Middle-Upper Proterozoic Suberathcm of the middle of northern margin of Yangtze Platform could be classified ...According to Ihe combinations of mctallogcnetic elements and minerals assemblages,the Au-Ag deposits in the Middle-Upper Proterozoic Suberathcm of the middle of northern margin of Yangtze Platform could be classified into four types,(l)Au-Ag-Pb-Zn type,(2)Au-Ag-Te type,(3)Au-quartz vein type,(4)Au-Ag-Pb-Zn-Ba type.The Yangpin formation and the upper Dangyuhe subformation,which belong to Wudangshan group,are regarded as favorable strata for Au-Ag mineralization by systematic assessments for Au-Ag bearing ability of the strata,as well as the felsic rocks of Bikou group.The mctallogcnetic physicochemical conditions and the stable isotopic compositions(S.Pb,H.O,C)have been studied in this paper.The sources of metallogenetic materials,origins of fluids and genesis of various deposits have also been studied.展开更多
To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles,PM_（2.5） and size-segregated aerosol particles were collected daily during fall at an urban site ...To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles,PM_（2.5） and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju,Korea.During the study period,the total concentration of secondary ionic species（SIS） contributed an average of 43.9% to the PM_（2.5） ,whereas the contribution of SIS to the PM_（2.5） during the haze period was 62.3%.The NO_3 and SO^（2-）_4 concentrations in PM_（2.5） during the haze period were highly elevated,being 13.4 and 5.0 times higher than those during non-haze period,respectively.The PM,NO^-_3,SO^（2-）_4,oxalate,water-soluble organic carbon（WSOC）,and humic-like substances（HULIS） had tri-modal size distributions peaks at 0.32,1.0,and 5.2 μm during the non-haze and haze periods.However,during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32 μm,while on October 21 when the heaviest haze event occurred,they had predominant droplet mode size distributions peaking at 1.00 μm.Moreover,strong correlations of WSOC and HULIS with SO^（2-）_4,oxalate,and K＋at particle sizes of 〈 1.8 μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS formations.It was found that the factors affecting haze formation could be the local stable synoptic conditions,including the weak surface winds and high surface pressures,the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula,as well as the locally emitted and produced aerosol particles.展开更多
In this paper, an explicit three_level symmetrical differencing scheme with parameters for solving parabolic partial differential equation of three_dimension will be considered. The stability condition and local trunc...In this paper, an explicit three_level symmetrical differencing scheme with parameters for solving parabolic partial differential equation of three_dimension will be considered. The stability condition and local truncation error for the scheme are r<1/2 and O( Δ t 2+ Δ x 4+ Δ y 4+ Δ z 4) ,respectively.展开更多
Fundamental metrology is closely tied to scientific advancement and requires well-equipped facilities to achieve low measurement uncertainty in rigorous experiments.Addressing the±0.1 K high-stability temperature...Fundamental metrology is closely tied to scientific advancement and requires well-equipped facilities to achieve low measurement uncertainty in rigorous experiments.Addressing the±0.1 K high-stability temperature control issue of the precision laboratory radiant air conditioning system,this study investigated the influence of different radiant panel area ratios,laying methods,cold source water supply temperature fluctuations,and external environmental disturbances by simulations.The results indicate that:(1)the larger the ratio of radiant panel area,the greater the fluctuation in equipment surface temperature;(2)the surface temperature of the measurement equipment can satisfy±0.1 K control temperature stability requirement when the fluctuations of the surface temperature of radiant panels and glass window are within±0.5 K and±1 K respectively without radiant panels on the ceiling;(3)the surface temperature of the measurement equipment can satisfy±0.1 K control temperature stability requirement when the fluctuations of the surface temperature of radiant panels and glass window are within±0.2 K and±2 K respectively with radiant panels on the ceiling.This study provides a reference for the design and operation control of air conditioning systems in fundamental metrology.展开更多
基金supported by the China Baowu Low Carbon Metallurgy Innovation Foundation(No.202114)National Natural Science Foundation of China(No.51874056)Sichuan Science and Technology Program(2025ZNSFSC0378).
文摘From the perspective of facilitating the design of fluidized hydrogen reduction reactors for iron ore powder and maintaining stable operation,the operational conditions and bubble behavior in stable state fluidization of multi-particle size systems were investigated through cold-state experiments.To facilitate the identification of bubble behavior,a two-dimensional bubbling bed cold-state experiment was carried out using iron ore powder with a narrow particle size distribution and glass beads.Initially,the multi-stage fluidization characteristics of iron ore powder were examined.Then,using Geldart B-type glass beads to simulate a multi-particle size composition system,the particle size range and superficial gas velocity range for stable operation of the multi-particle composition system were explored.When the mass percentage of 150-μm glass beads was 15%,the stable fluidization operational gas velocity range was found to be(1.05-1.21)umf,where umf is the minimum fluidization velocity;when the content was 20%,the stable fluidized superficial gas velocity range was(1.09-1.26)umf.Under stable fluidization operating conditions,the dynamic behavior of bubbles(average equivalent diameter,rising velocity,and lateral migration velocity)was studied,and the quantitative relationship between the average equivalent diameter of bubbles and bed height in multi-particle size systems under stable fluidization conditions was also corrected.Additionally,the correlation between bubble rising velocity and bubble average equivalent diameter was established.
基金Foundation items:The National Natural Science Foundation of China (No.10571026)the Specialized Research Fund for the Doctoral Program ofHigher Education (No.20060286006)
文摘A ring R is said to be satisfying P-stable range provided that whenever aR ＋ bR = R, there exists y ∈ P（R） such that a ＋ by is a unit of R, where P（R） is the subset of R which satisfies the property that up, pu∈ P（R） for every unit u of R and p ∈P（R）. By studying this ring, some known results of rings satisfying unit-1 stable range, （ S, 2） -stable range, weakly unit 1- stable range and stable range one are unified. An element of a ring is said to be UR if it is the sum of a unit and a regular dement and a ring is said to be satisfying UR-stable range if R has P-stable range and P（R） is the set of all UR-elements of R, Some properties of this ring are studied and it is proven that if R satisfies UR-stahle range then so does any n × n matrix ring over R.
文摘In this paper we study the formal triangular matrix ring T =and give some necessary and sufficient conditions for T to be (strongly) separative, m-fold stable and unit 1-stable. Moreover, a condition for finitely generated projec-tive T-modules to have n in the stable range is given under the assumption that A and B are exchange rings.
基金Project supported by the National Basic Research Program of China (Grant No 2006CB705500)the National Natural Science Foundation of China (Grant Nos 10662002 and 10532060)+1 种基金the Special Foundation for the New Century Talents Program of Guangxi Zhuang Autonomous Region, China (Grant No 2005205)the Research Grants from City University of Hong Kong (Grant No SRG7002226(BC))
文摘Based on the optimal velocity models, an extended model is proposed, in which multi-veloclty-dllterence aheacl is taken into consideration. The damping effect of the multi-velocity-difference ahead has been investigated by means of analytical and numerical methods. Results indicate that the multi-velocity-difference leads to the enhancement of stability of traffic flow, suppression of the emergence of traffic jamming, and reduction of the energy consumption.
文摘According to Ihe combinations of mctallogcnetic elements and minerals assemblages,the Au-Ag deposits in the Middle-Upper Proterozoic Suberathcm of the middle of northern margin of Yangtze Platform could be classified into four types,(l)Au-Ag-Pb-Zn type,(2)Au-Ag-Te type,(3)Au-quartz vein type,(4)Au-Ag-Pb-Zn-Ba type.The Yangpin formation and the upper Dangyuhe subformation,which belong to Wudangshan group,are regarded as favorable strata for Au-Ag mineralization by systematic assessments for Au-Ag bearing ability of the strata,as well as the felsic rocks of Bikou group.The mctallogcnetic physicochemical conditions and the stable isotopic compositions(S.Pb,H.O,C)have been studied in this paper.The sources of metallogenetic materials,origins of fluids and genesis of various deposits have also been studied.
基金supported by the Basic Science Research Programs through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(NRF2014R1A1A4A01003896)the support from the BK21 Plus program through the NRF funded by the MOE
文摘To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles,PM_（2.5） and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju,Korea.During the study period,the total concentration of secondary ionic species（SIS） contributed an average of 43.9% to the PM_（2.5） ,whereas the contribution of SIS to the PM_（2.5） during the haze period was 62.3%.The NO_3 and SO^（2-）_4 concentrations in PM_（2.5） during the haze period were highly elevated,being 13.4 and 5.0 times higher than those during non-haze period,respectively.The PM,NO^-_3,SO^（2-）_4,oxalate,water-soluble organic carbon（WSOC）,and humic-like substances（HULIS） had tri-modal size distributions peaks at 0.32,1.0,and 5.2 μm during the non-haze and haze periods.However,during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32 μm,while on October 21 when the heaviest haze event occurred,they had predominant droplet mode size distributions peaking at 1.00 μm.Moreover,strong correlations of WSOC and HULIS with SO^（2-）_4,oxalate,and K＋at particle sizes of 〈 1.8 μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS formations.It was found that the factors affecting haze formation could be the local stable synoptic conditions,including the weak surface winds and high surface pressures,the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula,as well as the locally emitted and produced aerosol particles.
文摘In this paper, an explicit three_level symmetrical differencing scheme with parameters for solving parabolic partial differential equation of three_dimension will be considered. The stability condition and local truncation error for the scheme are r<1/2 and O( Δ t 2+ Δ x 4+ Δ y 4+ Δ z 4) ,respectively.
基金support from the Key Projects in the National Science&Technology Program(Grant No.2022YFE0210200)Open Foundation of CAS Key Laboratory of Cryogenics,TIPC,(Grant No.CRYO202213)+1 种基金Fundamental Research Funds for the Central Universities(Grant No.N2325016)Natural Science Foundation of Liaoning Province(Grant No.2023-MSBA-099).
文摘Fundamental metrology is closely tied to scientific advancement and requires well-equipped facilities to achieve low measurement uncertainty in rigorous experiments.Addressing the±0.1 K high-stability temperature control issue of the precision laboratory radiant air conditioning system,this study investigated the influence of different radiant panel area ratios,laying methods,cold source water supply temperature fluctuations,and external environmental disturbances by simulations.The results indicate that:(1)the larger the ratio of radiant panel area,the greater the fluctuation in equipment surface temperature;(2)the surface temperature of the measurement equipment can satisfy±0.1 K control temperature stability requirement when the fluctuations of the surface temperature of radiant panels and glass window are within±0.5 K and±1 K respectively without radiant panels on the ceiling;(3)the surface temperature of the measurement equipment can satisfy±0.1 K control temperature stability requirement when the fluctuations of the surface temperature of radiant panels and glass window are within±0.2 K and±2 K respectively with radiant panels on the ceiling.This study provides a reference for the design and operation control of air conditioning systems in fundamental metrology.
