Following the theory and definition of the Corioli force in physics, the Corioli force at the site of the M=8.1 Kunlun Mountain Pass earthquake on November 14, 2001, is examined in this paper on the basis of a statist...Following the theory and definition of the Corioli force in physics, the Corioli force at the site of the M=8.1 Kunlun Mountain Pass earthquake on November 14, 2001, is examined in this paper on the basis of a statistical research on relationship between the Corioli force effect and the maximum aftershock magnitude of 20 earthquakes with M7.5 in Chinese mainland, and then the variation tendency of aftershock activity of the M=8.1 earthquake is discussed. The result shows: a) Analyzing the Corioli force effect is an effective method to predict maximum aftershock magnitude of large earthquakes in Chinese mainland. For the sinistral slip fault and the reverse fault with its hanging wall moving toward the right side of the cross-focus meridian plane, their Corioli force pulls the two fault walls apart, decreasing frictional resistance on fault plane during the fault movement and releasing elastic energy of the mainshock fully, so the maximum magnitude of aftershocks would be low. For the dextral slip fault, its Corioli force presses the two walls against each other and increases the frictional resistance on fault plane, prohibiting energy release of the mainshock, so the maximum magnitude of aftershocks would be high. b) The fault of the M=8.1 Kunlun Mountain earthquake on Nov. 14, 2001 is essentially a sinistral strike-slip fault, and the Corioli force pulled the two fault walls apart. Magnitude of the induced stress is about 0.06 MPa. After a comparison analysis, we suggest that the aftershock activity level will not be high in the late period of this earthquake sequence, and the maximum magnitude of the whole aftershocks sequence is estimated to be about 6.0.展开更多
SDA (Structural Decomposition Analysis) model was applied to analyze the driving factors of embodied carbon and SO_(2) emissions transferred in Shanxi during 2007-2012 based on the input-output model from the perspect...SDA (Structural Decomposition Analysis) model was applied to analyze the driving factors of embodied carbon and SO_(2) emissions transferred in Shanxi during 2007-2012 based on the input-output model from the perspectives of region and industry.The results showed that the change of embodied carbon emissions and embodied SO_(2) emissions of Shanxi and other regions were hindered by the carbon (sulfur) emissions strength effect,but promoted by the intermediate (final) demand scale effect,the intermediate (final) structure effect and the input-output structure effect.The carbon emissions strength effect had a significant contribution to reducing the embodied carbon emissions transferred from industries in Shanxi to other regions.The intermediate (final) demand scale effect was the driving factor to increase the embodied carbon emissions transferred from industries in Shanxi to other regions.The sulfur emissions strength effect was the only factor that reduced the embodied SO_(2) emissions transferred from Shanxi to other industries.The change of embodied carbon emissions from industries in other regions to Shanxi was hindered by the carbon emissions strength effect,but the input-output structure effect and final demand scale effect both increased the embodied carbon emissions from industries in other regions to Shanxi.The change of the embodied SO_(2) emissions transferred from industries in other regions to Shanxi was inhibited by the sulfur emissions strength effect,but the input-output structure effect,the intermediate demand structure effect and the final demand scale effect were both the driving force effect of increasing the embodied SO_(2) emissions transferred from industries in other regions to Shanxi.The corresponding suggestions and measures were put forward.展开更多
The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal ...The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal counterparts,one gains insights into the system's response under new mathematical frameworks.This paper presents a novel method for converting standard continuous differential equations into their fractal equivalents.This conversion occurs after the nonlinear system is transformed into its linear equivalent.Numerical analyses show that there are several resonance sites in the fractal system,which differ from the one resonance point found in the continuous system.One important finding is that the fractal system loses some of its stabilizing power when decaying behavior is transformed into a diffuse pattern.Interestingly,a decrease in the fractal order in resonance settings shows a stabilizing impact,highlighting the dynamics'complexity inside fractal systems.This endeavor to convert to fractals is a revolutionary technique that is being employed for the first time.展开更多
In the framework of the Skyrme-Hartree-Fock approach with 36 sets of the TI J parameterizations,the tensor force effect on the evolution of the single-proton states in the calcium isotopes is systematically investigat...In the framework of the Skyrme-Hartree-Fock approach with 36 sets of the TI J parameterizations,the tensor force effect on the evolution of the single-proton states in the calcium isotopes is systematically investigated.It is shown that the single-proton states with higher angular momenta are influenced significantly by the tensor force and the trend in the evolution of somesingle-particle energy differences with the mass number of the isotopes depends sensitively on a parameter βT associated with the intensity of the tensor force.To understand this phenomenon,we analyze the spin-orbit potentials and the radial wave functions of relevant single-proton orbits in detail.In addition,it is found that some TI J interactions could cause the 2s1/21d3/2 energy level inversion in 48Ca.展开更多
Pressure-sensitive paint(PSP) technique was employed to experimentally investigate the aerodynamic force effect of vacuum plume in this study. The characterization and comparison for two types of PSP were firstly cond...Pressure-sensitive paint(PSP) technique was employed to experimentally investigate the aerodynamic force effect of vacuum plume in this study. The characterization and comparison for two types of PSP were firstly conducted in an air pressure range from0.05 to 5000 Pa. The PSPs were prepared using PtTFPP as the active dye and different binders, i.e., polymer-ceramic(PC) and poly(1-trimethylsilyl-1-propyne) [poly(TMSP)]. The static calibrations showed that PtTFPP/poly(TMSP) had a higher pressure sensitivity and a lower temperature dependency compared to PtTFPP/PC in this pressure range. The pressure distributions of a single and two interacting plumes impinging onto a flat plate model were measured using PSP technique. The experimental data were compared to numerical solutions that combined both the computed fluid dynamics(CFD) and direct simulation Monte Carlo(DSMC) methods. Remarkable agreements were achieved, demonstrating the feasibility and accuracy of the numerical approach.Finally, the aerodynamic force effect of interacting plumes at different separation distances was investigated numerically.展开更多
A unified description of finite nuclei and equation of state of neutron stars presents both a major challenge and also opportunities for understanding nuclear interactions.Inspired by the Lee-Huang-Yang formula of har...A unified description of finite nuclei and equation of state of neutron stars presents both a major challenge and also opportunities for understanding nuclear interactions.Inspired by the Lee-Huang-Yang formula of hardsphere gases,we develop effective nuclear interactions with an additional high-order density dependent term.While the original Skyrme force SLy4 is widely used in studies of neutron stars,there are not satisfactory global descriptions of finite nuclei.The refitted SLy4' force can improve descriptions of finite nuclei but slightly reduces the radius of neutron star of 1.4 M_☉ with M_☉ being the solar mass.We find that the extended SLy4 force with a higher-order density dependence can properly describe properties of both finite nuclei and GW170817 binary neutron stars,including the mass-radius relation and the tidal deformability.This demonstrates the essential role of high-order density dependence at ultrahigh densities.Our work provides a unified and predictive model for neutron stars,as well as new insights for the future development of effective interactions.展开更多
The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to m...The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to model the water resisting pipe-phalanx within the jacket. The shielding factor for ice force corresponding to different conditions are given in this paper. The research indicates that there are many factors, including the longitudinal and lateral spacing between the front and back pile-row, ice attacking angle and the ratio of pile diameter to ice thickness, that influence the shielding effect on ice force.展开更多
A modified energy-balance equation accounting for P-delta effects and hysteretic behavior of reinforced concrete members is derived. Reduced hysteretic properties of structural components due to combined stiffness and...A modified energy-balance equation accounting for P-delta effects and hysteretic behavior of reinforced concrete members is derived. Reduced hysteretic properties of structural components due to combined stiffness and strength degradation and pinching effects, and hysteretic damping are taken into account in a simple manner by utilizing plastic energy and seismic input energy modification factors. Having a pre-selected yield mechanism, energy balance of structure in inelastic range is considered. P-delta effects are included in derived equation by adding the external work of gravity loads to the work of equivalent inertia forces and equating the total external work to the modified plastic energy. Earthquake energy input to multi degree of freedom（MDOF） system is approximated by using the modal energy-decomposition. Energybased base shear coefficients are verified by means of both pushover analysis and nonlinear time history（NLTH） analysis of several RC frames having different number of stories. NLTH analyses of frames are performed by using the time histories of ten scaled ground motions compatible with elastic design acceleration spectrum and fulfilling duration/amplitude related requirements of Turkish Seismic Design Code. The observed correlation between energy-based base shear force coefficients and the average base shear force coefficients of NLTH analyses provides a reasonable confidence in estimation of nonlinear base shear force capacity of frames by using the derived equation.展开更多
The temperature rise of He Ⅱ transfer system due to the negative Joule-Thomson(JT)effect is one of the major problems in the He Ⅱ forced flow system design.Negative Joule-Thomson effect of the He Ⅱ forced flow was ...The temperature rise of He Ⅱ transfer system due to the negative Joule-Thomson(JT)effect is one of the major problems in the He Ⅱ forced flow system design.Negative Joule-Thomson effect of the He Ⅱ forced flow was analyzed and calculated in this paper.The temperature rise due to the heat leak along the transfer pipeline was calculated by the simplified equation and was modified by considering the negative Joule-Thomson effect.The modified results were compared with the temperature rise obtained by non-linear differential equations with consideration of the pressure gradient.The results show that the pressure gradient has strong effect on the temperature distribution.The modified results are in good agreement with the values calculated by the complicated equation,which verifies the effectiveness of the simplified equation in calculating the temperature rise when the negative JT effect of He Ⅱ is known.展开更多
It is shown that the introduction of thermal effect, zero-point vibration, and phonon anharmonicity to a high quality and first-principle-Sased force field （atomic potential） results in a significant improvement in ...It is shown that the introduction of thermal effect, zero-point vibration, and phonon anharmonicity to a high quality and first-principle-Sased force field （atomic potential） results in a significant improvement in predict- ing the densities for the α phase crystalline hexahydro-1,3,5-trinitro-l,3,5-triazine （RDX）, and derivation of its high-fidelity Hugoniot locus and Mie-Grfineisen equation of state covering a very wide range of pressures and temperatures. This work can be used to efficiently and accurately predict the thermophysical properties of solid explosives over the pressures and temperatures to which they are subjected, which is a long-standing issue in the field of energetic materials.展开更多
This paper mainly focuses on the establishment of an effective static estimation method for the extreme wind-induced force for clips between purlins and metal panels of the standing-seam metal roofing system(hereinaft...This paper mainly focuses on the establishment of an effective static estimation method for the extreme wind-induced force for clips between purlins and metal panels of the standing-seam metal roofing system(hereinafter referred to as SMRS)of typical double-slope light-weight steel portal frame structure considering dynamic characteristics of wind and structure.First,simultaneous pressure measurement with rigid gable roof models was conducted mainly considering the length-span ratio in the boundary layer wind tunnel of Tokyo Polytechnic University,Japan.Then,finite element modeling for SMRS according to the wind load path in the roofing system was carried out to check the actual wind load of the clips based on the traditional calculation method provided in design codes,and the spatial correlation of fluctuating wind pressure on the roof surface,as well as the dynamic effect of the roof structure itself,had been considered.According to the related Chinese,American,and Japanese codes,a magnification coefficient based on the traditional method of static wind-induced force for the clips was calculated and compared.Finally,a simplified estimation method of effective wind-induced force for the clips in typical zones on the roof surface considering dynamic characteristics was proposed.展开更多
In order to remove efficiently haled-particles emissions from coal combustions, a new way was used to put forward the process of agglomeration and the atomization was produced by the nozzle and then sprayed into the ...In order to remove efficiently haled-particles emissions from coal combustions, a new way was used to put forward the process of agglomeration and the atomization was produced by the nozzle and then sprayed into the flue before precipitation devices of power station boiler in order to make inhaled-particles agglomerate into bigger particles, which can be easily removed but not change existing running conditions of boiler. According to this idea, a model is set up to study agglomeration rate and effect forces between fly ash inhaled-particles and atomized agglomerator particles. The developed agglomeration rate was expressed by relative particle number decreasing speed per unit volume. The result showed that viscosity force and flow resistance force give main influences on agglomeration effect of inhaled-particles, while springiness force and gravity have little effect on agglomeration effect of theirs. Factors influencing the agglomeration rate and effect forces are studied, including agglomerator concentration, agglomerator flux and agglomerator density, atomized-particles diameters and inhaled-particles diameter and so on.展开更多
This study simulates the effective radiative forcing （ERF） of tropospheric ozone from 1850 to 2013 and its effects on global climate using an aerosol-climate coupled model, BCC_AGCM2.0. I_CUACE/Aero, in combination ...This study simulates the effective radiative forcing （ERF） of tropospheric ozone from 1850 to 2013 and its effects on global climate using an aerosol-climate coupled model, BCC_AGCM2.0. I_CUACE/Aero, in combination with OMI （Ozone Monitoring Instrument） satellite ozone data. According to the OMI observations, the global annual mean tropospheric col- umn ozone （TCO） was 33.9 DU in 2013, and the largest TCO was distributed in the belts between 30°N and 45°N and at approximately 30°S; the annual mean TCO was higher in the Northern Hemisphere than that in the Southern Hemisphere; and in boreal summer and autumn, the global mean TCO was higher than in winter and spring. The simulated ERF due to the change in tropospheric ozone concentration from 1850 to 2013 was 0.46 W m-2, thereby causing an increase in the global annual mean surface temperature by 0.36°C, and precipitation by 0.02 mm d-1 （the increase of surface temperature had a significance level above 95%）. The surface temperature was increased more obviously over the high latitudes in both hemispheres, with the maximum exceeding 1.4°C in Siberia. There were opposite changes in precipitation near the equator, with an increase of 0.5 mm d- 1 near the Hawaiian Islands and a decrease of about -0.6 mm d- 1 near the middle of the Indian Ocean.展开更多
An atmospheric general circulation model BCC_AGCM2.0 and observation data from ARIS were used to calculate the effective radiative forcing（ERF） due to increased methane concentration since pre-industrial times and i...An atmospheric general circulation model BCC_AGCM2.0 and observation data from ARIS were used to calculate the effective radiative forcing（ERF） due to increased methane concentration since pre-industrial times and its impacts on climate. The ERF of methane from 1750 to2011 was 0.46 W m^-2 by taking it as a well-mixed greenhouse gas, and the inhomogeneity of methane increased its ERF by about 0.02 W m^-2.The change of methane concentration since pre-industrial led to an increase of 0.31 ℃ in global mean surface air temperature and 0.02 mm d 1in global mean precipitation. The warming was prominent over the middle and high latitudes of the Northern Hemisphere（with a maximum increase exceeding 1.4℃）. The precipitation notably increased（maximum increase of 1.8 mm d^-1） over the ocean between 10°N and 20° N and significantly decreased（maximum decrease 〉-0.6 mm d^-1） between 10° S and 10° N. These changes caused a northward movement of precipitation cell in the Intertropical Convergence Zone（ITCZ）. Cloud cover significantly increased（by approximately 4%） in the high latitudes in both hemispheres, and sharply decreased（by approximately 3%） in tropical areas.展开更多
To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experimen...To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experiments were used to validate the effects of using surfactants;the results show that after dealing with vacuum saturation with water,the volume of micropores decreases,which results in a larger average pore size,and the volume of transitional pores,mesopores,macropores and total pores increases.Based on the distribution of pore size,the operation mode of ‘‘water infusion after gas extraction,then continuing gas extraction" is recommended to improve the volume of coal mine gas drainage.When the reflectance of vitrinite in coal samples is less than 1,using the surfactants Fast T,1631,APG,BS can mitigate the damage caused by the water blocking effect.But when the reflectance of vitrinite is larger than 1.4,the damage caused by the water blocking effect can be increased.When the surfactant CMC is used in hydraulic applications,the capillary forces of coal samples are almost negative,which means the capillary force is in the same direction as the gas extraction.The direction of capillary forces benefits the gas flow.So,using CMC can play an active role in removing the water blocking effect.Centrifugal experiments confirm that using CMC can effectively remove the water blocking effect,which has a beneficial effect on improving the gas drainage volume.展开更多
Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings ...Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data processing.In this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure measurements.Furthermore,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors.展开更多
The effective radiative forcing （ERF） and associated surface air temperature change over eastern China are estimated using multi-model results from CMIP5 （Coupled Model Intercomparison Project Phase 5）. The model ...The effective radiative forcing （ERF） and associated surface air temperature change over eastern China are estimated using multi-model results from CMIP5 （Coupled Model Intercomparison Project Phase 5）. The model results show that, relative to 1850, the multi-model and annual mean aerosol ERF for the year 2005 is -4.14 W m^-2 at the top of the atmosphere over eastern China （20°-45°N, 105°-122.5°E）. As a result of this ERF, the multi-model and annual mean surface air temperature change in eastern China during 1850-2005 is -1.05℃, leading to a climate sensitivity of 0.24℃/ （Wm^-2） in this region.展开更多
Bent-housing motor is the most widely used directional drilling tool,but it often encounters the problem of high friction when sliding drilling in horizontal wells.In this paper,a mathematical model is proposed to sim...Bent-housing motor is the most widely used directional drilling tool,but it often encounters the problem of high friction when sliding drilling in horizontal wells.In this paper,a mathematical model is proposed to simulate slide drilling with a friction reduction tool of axial vibration.A term called dynamic effective tractoring force(DETF)is defined and used to evaluate friction reduction effectiveness.The factors influencing the DETF are studied,and the tool placement optimization problem is investigated.The studyfinds that the drilling rate of penetration(ROP)can lower the DETF but does not change the trend of the DETF curve.To effectively work,the shock tool stiffness must be greater than some critical value.For the case study,the best oscillating frequency is within 15∼20 Hz.The reflection of the vibration at the bit boundary can intensify or weaken the friction reduction effec-tiveness,depending on the distance between the hydraulic oscillator and the bit.The optimal placement position corresponds to the plateau stage of the DETF curve.The reliability of the method is verified by thefield tests.The proposed method can provide a design and use guide to hydraulic oscillators and improve friction reduction effectiveness in horizontal wells.展开更多
In this paper the effects of temperature on the radial breathing modes （RBMs） and radial wave propaga- tion in multiwall carbon nanotubes （MWCNTs） are inves- tigated using a continuum model of multiple elastic iso...In this paper the effects of temperature on the radial breathing modes （RBMs） and radial wave propaga- tion in multiwall carbon nanotubes （MWCNTs） are inves- tigated using a continuum model of multiple elastic isotropic shells. The van der Waals forces between tubes are simulated as a nonlinear function of interlayer spacing of MWCNTs. The governing equations are solved using a finite element method. A wide range of innermost radius-to-thickness ratio of MWCNTs is considered to enhance the investigation. The presented solution is verified by comparing the results with those reported in the literature. The effects of temperature on the van der Waals interaction coefficient between layers of MWCNTs are examined. It is found that the variation of the van der Waals interaction coefficient at high temperature is sensible. Subsequently, variations of RBM frequencies and radial wave propagation in MWCNTs with temperatures up to 1 600 K are illustrated. It is shown that the thick MWC- NTs are more sensible to temperature than the thin ones.展开更多
A barotropic channel model in β-plane is used to study the effect of topographic forcing on the formation and maintenance of blocking. The approximate analytical solution of potential vorticity equation can show the ...A barotropic channel model in β-plane is used to study the effect of topographic forcing on the formation and maintenance of blocking. The approximate analytical solution of potential vorticity equation can show the main property of the whole process of blocking. It is indicated that the topographic forcing is one of the main factors causing the blocking process. The results suggest that the nonlinear interaction plays a very important role in the stable 'Ω' situation of blocking. The atmospheric circulation with periodic and low-frequency oscillation, perhaps, is partly caused by topographic forcing.展开更多
基金Key Project of Disaster Reduction of Jiangxi Province during the tenth Five-Year Plan (JX105-05).
文摘Following the theory and definition of the Corioli force in physics, the Corioli force at the site of the M=8.1 Kunlun Mountain Pass earthquake on November 14, 2001, is examined in this paper on the basis of a statistical research on relationship between the Corioli force effect and the maximum aftershock magnitude of 20 earthquakes with M7.5 in Chinese mainland, and then the variation tendency of aftershock activity of the M=8.1 earthquake is discussed. The result shows: a) Analyzing the Corioli force effect is an effective method to predict maximum aftershock magnitude of large earthquakes in Chinese mainland. For the sinistral slip fault and the reverse fault with its hanging wall moving toward the right side of the cross-focus meridian plane, their Corioli force pulls the two fault walls apart, decreasing frictional resistance on fault plane during the fault movement and releasing elastic energy of the mainshock fully, so the maximum magnitude of aftershocks would be low. For the dextral slip fault, its Corioli force presses the two walls against each other and increases the frictional resistance on fault plane, prohibiting energy release of the mainshock, so the maximum magnitude of aftershocks would be high. b) The fault of the M=8.1 Kunlun Mountain earthquake on Nov. 14, 2001 is essentially a sinistral strike-slip fault, and the Corioli force pulled the two fault walls apart. Magnitude of the induced stress is about 0.06 MPa. After a comparison analysis, we suggest that the aftershock activity level will not be high in the late period of this earthquake sequence, and the maximum magnitude of the whole aftershocks sequence is estimated to be about 6.0.
文摘SDA (Structural Decomposition Analysis) model was applied to analyze the driving factors of embodied carbon and SO_(2) emissions transferred in Shanxi during 2007-2012 based on the input-output model from the perspectives of region and industry.The results showed that the change of embodied carbon emissions and embodied SO_(2) emissions of Shanxi and other regions were hindered by the carbon (sulfur) emissions strength effect,but promoted by the intermediate (final) demand scale effect,the intermediate (final) structure effect and the input-output structure effect.The carbon emissions strength effect had a significant contribution to reducing the embodied carbon emissions transferred from industries in Shanxi to other regions.The intermediate (final) demand scale effect was the driving factor to increase the embodied carbon emissions transferred from industries in Shanxi to other regions.The sulfur emissions strength effect was the only factor that reduced the embodied SO_(2) emissions transferred from Shanxi to other industries.The change of embodied carbon emissions from industries in other regions to Shanxi was hindered by the carbon emissions strength effect,but the input-output structure effect and final demand scale effect both increased the embodied carbon emissions from industries in other regions to Shanxi.The change of the embodied SO_(2) emissions transferred from industries in other regions to Shanxi was inhibited by the sulfur emissions strength effect,but the input-output structure effect,the intermediate demand structure effect and the final demand scale effect were both the driving force effect of increasing the embodied SO_(2) emissions transferred from industries in other regions to Shanxi.The corresponding suggestions and measures were put forward.
文摘The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal counterparts,one gains insights into the system's response under new mathematical frameworks.This paper presents a novel method for converting standard continuous differential equations into their fractal equivalents.This conversion occurs after the nonlinear system is transformed into its linear equivalent.Numerical analyses show that there are several resonance sites in the fractal system,which differ from the one resonance point found in the continuous system.One important finding is that the fractal system loses some of its stabilizing power when decaying behavior is transformed into a diffuse pattern.Interestingly,a decrease in the fractal order in resonance settings shows a stabilizing impact,highlighting the dynamics'complexity inside fractal systems.This endeavor to convert to fractals is a revolutionary technique that is being employed for the first time.
基金supported by the National Natural Science Foundation of China (Grant Nos.10975190,11275271 and 11075213)the Funds for Creative Research Groups of China (Grant No.11021504)+2 种基金the Doctoral Funds of Guizhou Normal College (Grant No.12BS020)the Natural Science Foundation of Guizhou Province of China (Grant No.2013GZ62432)the Natural Science Foundation of Hebei Province of China (Grant No.2012210043)
文摘In the framework of the Skyrme-Hartree-Fock approach with 36 sets of the TI J parameterizations,the tensor force effect on the evolution of the single-proton states in the calcium isotopes is systematically investigated.It is shown that the single-proton states with higher angular momenta are influenced significantly by the tensor force and the trend in the evolution of somesingle-particle energy differences with the mass number of the isotopes depends sensitively on a parameter βT associated with the intensity of the tensor force.To understand this phenomenon,we analyze the spin-orbit potentials and the radial wave functions of relevant single-proton orbits in detail.In addition,it is found that some TI J interactions could cause the 2s1/21d3/2 energy level inversion in 48Ca.
文摘Pressure-sensitive paint(PSP) technique was employed to experimentally investigate the aerodynamic force effect of vacuum plume in this study. The characterization and comparison for two types of PSP were firstly conducted in an air pressure range from0.05 to 5000 Pa. The PSPs were prepared using PtTFPP as the active dye and different binders, i.e., polymer-ceramic(PC) and poly(1-trimethylsilyl-1-propyne) [poly(TMSP)]. The static calibrations showed that PtTFPP/poly(TMSP) had a higher pressure sensitivity and a lower temperature dependency compared to PtTFPP/PC in this pressure range. The pressure distributions of a single and two interacting plumes impinging onto a flat plate model were measured using PSP technique. The experimental data were compared to numerical solutions that combined both the computed fluid dynamics(CFD) and direct simulation Monte Carlo(DSMC) methods. Remarkable agreements were achieved, demonstrating the feasibility and accuracy of the numerical approach.Finally, the aerodynamic force effect of interacting plumes at different separation distances was investigated numerically.
基金Supported by the National Key R&D Program of China (Grant No.2018YFA0404403)the National Natural Science Foundation of China (Grant Nos.11975032,11835001,11790325,and 11961141003)。
文摘A unified description of finite nuclei and equation of state of neutron stars presents both a major challenge and also opportunities for understanding nuclear interactions.Inspired by the Lee-Huang-Yang formula of hardsphere gases,we develop effective nuclear interactions with an additional high-order density dependent term.While the original Skyrme force SLy4 is widely used in studies of neutron stars,there are not satisfactory global descriptions of finite nuclei.The refitted SLy4' force can improve descriptions of finite nuclei but slightly reduces the radius of neutron star of 1.4 M_☉ with M_☉ being the solar mass.We find that the extended SLy4 force with a higher-order density dependence can properly describe properties of both finite nuclei and GW170817 binary neutron stars,including the mass-radius relation and the tidal deformability.This demonstrates the essential role of high-order density dependence at ultrahigh densities.Our work provides a unified and predictive model for neutron stars,as well as new insights for the future development of effective interactions.
文摘The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to model the water resisting pipe-phalanx within the jacket. The shielding factor for ice force corresponding to different conditions are given in this paper. The research indicates that there are many factors, including the longitudinal and lateral spacing between the front and back pile-row, ice attacking angle and the ratio of pile diameter to ice thickness, that influence the shielding effect on ice force.
文摘A modified energy-balance equation accounting for P-delta effects and hysteretic behavior of reinforced concrete members is derived. Reduced hysteretic properties of structural components due to combined stiffness and strength degradation and pinching effects, and hysteretic damping are taken into account in a simple manner by utilizing plastic energy and seismic input energy modification factors. Having a pre-selected yield mechanism, energy balance of structure in inelastic range is considered. P-delta effects are included in derived equation by adding the external work of gravity loads to the work of equivalent inertia forces and equating the total external work to the modified plastic energy. Earthquake energy input to multi degree of freedom（MDOF） system is approximated by using the modal energy-decomposition. Energybased base shear coefficients are verified by means of both pushover analysis and nonlinear time history（NLTH） analysis of several RC frames having different number of stories. NLTH analyses of frames are performed by using the time histories of ten scaled ground motions compatible with elastic design acceleration spectrum and fulfilling duration/amplitude related requirements of Turkish Seismic Design Code. The observed correlation between energy-based base shear force coefficients and the average base shear force coefficients of NLTH analyses provides a reasonable confidence in estimation of nonlinear base shear force capacity of frames by using the derived equation.
基金Sponsored by the National Natural Science Foundation of China(Grant No.10872152)the Ministries and Commissions of Science and Technology of Shanghai Government (Grant No. 03DZ 14014) for Shanghai Jiaotong University
文摘The temperature rise of He Ⅱ transfer system due to the negative Joule-Thomson(JT)effect is one of the major problems in the He Ⅱ forced flow system design.Negative Joule-Thomson effect of the He Ⅱ forced flow was analyzed and calculated in this paper.The temperature rise due to the heat leak along the transfer pipeline was calculated by the simplified equation and was modified by considering the negative Joule-Thomson effect.The modified results were compared with the temperature rise obtained by non-linear differential equations with consideration of the pressure gradient.The results show that the pressure gradient has strong effect on the temperature distribution.The modified results are in good agreement with the values calculated by the complicated equation,which verifies the effectiveness of the simplified equation in calculating the temperature rise when the negative JT effect of He Ⅱ is known.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11372053,11402031,11221202 and 11172044the Opening Project of the State Key Laboratory of Explosion Science and Technology under Grant No KFJJ14-06M
文摘It is shown that the introduction of thermal effect, zero-point vibration, and phonon anharmonicity to a high quality and first-principle-Sased force field （atomic potential） results in a significant improvement in predict- ing the densities for the α phase crystalline hexahydro-1,3,5-trinitro-l,3,5-triazine （RDX）, and derivation of its high-fidelity Hugoniot locus and Mie-Grfineisen equation of state covering a very wide range of pressures and temperatures. This work can be used to efficiently and accurately predict the thermophysical properties of solid explosives over the pressures and temperatures to which they are subjected, which is a long-standing issue in the field of energetic materials.
基金financial support of the National Key Research and Development Program of China(No.2017YFC0703803)the Joint Usage/Research Center(JURC)project“Wind-induced Load Estimation for Clips of Standing-seam Roofing System Considering Dynamic Characteristics”from Tokyo Polytechnic University(2018 FY)the National Natural Science Foundation of China(Grant No.51978500).
文摘This paper mainly focuses on the establishment of an effective static estimation method for the extreme wind-induced force for clips between purlins and metal panels of the standing-seam metal roofing system(hereinafter referred to as SMRS)of typical double-slope light-weight steel portal frame structure considering dynamic characteristics of wind and structure.First,simultaneous pressure measurement with rigid gable roof models was conducted mainly considering the length-span ratio in the boundary layer wind tunnel of Tokyo Polytechnic University,Japan.Then,finite element modeling for SMRS according to the wind load path in the roofing system was carried out to check the actual wind load of the clips based on the traditional calculation method provided in design codes,and the spatial correlation of fluctuating wind pressure on the roof surface,as well as the dynamic effect of the roof structure itself,had been considered.According to the related Chinese,American,and Japanese codes,a magnification coefficient based on the traditional method of static wind-induced force for the clips was calculated and compared.Finally,a simplified estimation method of effective wind-induced force for the clips in typical zones on the roof surface considering dynamic characteristics was proposed.
文摘In order to remove efficiently haled-particles emissions from coal combustions, a new way was used to put forward the process of agglomeration and the atomization was produced by the nozzle and then sprayed into the flue before precipitation devices of power station boiler in order to make inhaled-particles agglomerate into bigger particles, which can be easily removed but not change existing running conditions of boiler. According to this idea, a model is set up to study agglomeration rate and effect forces between fly ash inhaled-particles and atomized agglomerator particles. The developed agglomeration rate was expressed by relative particle number decreasing speed per unit volume. The result showed that viscosity force and flow resistance force give main influences on agglomeration effect of inhaled-particles, while springiness force and gravity have little effect on agglomeration effect of theirs. Factors influencing the agglomeration rate and effect forces are studied, including agglomerator concentration, agglomerator flux and agglomerator density, atomized-particles diameters and inhaled-particles diameter and so on.
基金supported by the National Natural Science Foundation of China(Grant No.41575002)
文摘This study simulates the effective radiative forcing （ERF） of tropospheric ozone from 1850 to 2013 and its effects on global climate using an aerosol-climate coupled model, BCC_AGCM2.0. I_CUACE/Aero, in combination with OMI （Ozone Monitoring Instrument） satellite ozone data. According to the OMI observations, the global annual mean tropospheric col- umn ozone （TCO） was 33.9 DU in 2013, and the largest TCO was distributed in the belts between 30°N and 45°N and at approximately 30°S; the annual mean TCO was higher in the Northern Hemisphere than that in the Southern Hemisphere; and in boreal summer and autumn, the global mean TCO was higher than in winter and spring. The simulated ERF due to the change in tropospheric ozone concentration from 1850 to 2013 was 0.46 W m-2, thereby causing an increase in the global annual mean surface temperature by 0.36°C, and precipitation by 0.02 mm d-1 （the increase of surface temperature had a significance level above 95%）. The surface temperature was increased more obviously over the high latitudes in both hemispheres, with the maximum exceeding 1.4°C in Siberia. There were opposite changes in precipitation near the equator, with an increase of 0.5 mm d- 1 near the Hawaiian Islands and a decrease of about -0.6 mm d- 1 near the middle of the Indian Ocean.
基金supported by the National Natural Science Foundation of China (41575002, 91644211)
文摘An atmospheric general circulation model BCC_AGCM2.0 and observation data from ARIS were used to calculate the effective radiative forcing（ERF） due to increased methane concentration since pre-industrial times and its impacts on climate. The ERF of methane from 1750 to2011 was 0.46 W m^-2 by taking it as a well-mixed greenhouse gas, and the inhomogeneity of methane increased its ERF by about 0.02 W m^-2.The change of methane concentration since pre-industrial led to an increase of 0.31 ℃ in global mean surface air temperature and 0.02 mm d 1in global mean precipitation. The warming was prominent over the middle and high latitudes of the Northern Hemisphere（with a maximum increase exceeding 1.4℃）. The precipitation notably increased（maximum increase of 1.8 mm d^-1） over the ocean between 10°N and 20° N and significantly decreased（maximum decrease 〉-0.6 mm d^-1） between 10° S and 10° N. These changes caused a northward movement of precipitation cell in the Intertropical Convergence Zone（ITCZ）. Cloud cover significantly increased（by approximately 4%） in the high latitudes in both hemispheres, and sharply decreased（by approximately 3%） in tropical areas.
基金financially supported by the National Natural Science Foundation of China (No.51504084)the Education Department of Fujian Province (No.JA15493)
文摘To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experiments were used to validate the effects of using surfactants;the results show that after dealing with vacuum saturation with water,the volume of micropores decreases,which results in a larger average pore size,and the volume of transitional pores,mesopores,macropores and total pores increases.Based on the distribution of pore size,the operation mode of ‘‘water infusion after gas extraction,then continuing gas extraction" is recommended to improve the volume of coal mine gas drainage.When the reflectance of vitrinite in coal samples is less than 1,using the surfactants Fast T,1631,APG,BS can mitigate the damage caused by the water blocking effect.But when the reflectance of vitrinite is larger than 1.4,the damage caused by the water blocking effect can be increased.When the surfactant CMC is used in hydraulic applications,the capillary forces of coal samples are almost negative,which means the capillary force is in the same direction as the gas extraction.The direction of capillary forces benefits the gas flow.So,using CMC can play an active role in removing the water blocking effect.Centrifugal experiments confirm that using CMC can effectively remove the water blocking effect,which has a beneficial effect on improving the gas drainage volume.
基金supported by the National Natural Science Foundation of China (90715040)
文摘Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data processing.In this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure measurements.Furthermore,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors.
基金supported by the National Basic Research Program of China[973 Program,grant number 2014CB441202]the National Natural Science Foundation of China[grant numbers41475137 and 91544219]
文摘The effective radiative forcing （ERF） and associated surface air temperature change over eastern China are estimated using multi-model results from CMIP5 （Coupled Model Intercomparison Project Phase 5）. The model results show that, relative to 1850, the multi-model and annual mean aerosol ERF for the year 2005 is -4.14 W m^-2 at the top of the atmosphere over eastern China （20°-45°N, 105°-122.5°E）. As a result of this ERF, the multi-model and annual mean surface air temperature change in eastern China during 1850-2005 is -1.05℃, leading to a climate sensitivity of 0.24℃/ （Wm^-2） in this region.
文摘Bent-housing motor is the most widely used directional drilling tool,but it often encounters the problem of high friction when sliding drilling in horizontal wells.In this paper,a mathematical model is proposed to simulate slide drilling with a friction reduction tool of axial vibration.A term called dynamic effective tractoring force(DETF)is defined and used to evaluate friction reduction effectiveness.The factors influencing the DETF are studied,and the tool placement optimization problem is investigated.The studyfinds that the drilling rate of penetration(ROP)can lower the DETF but does not change the trend of the DETF curve.To effectively work,the shock tool stiffness must be greater than some critical value.For the case study,the best oscillating frequency is within 15∼20 Hz.The reflection of the vibration at the bit boundary can intensify or weaken the friction reduction effec-tiveness,depending on the distance between the hydraulic oscillator and the bit.The optimal placement position corresponds to the plateau stage of the DETF curve.The reliability of the method is verified by thefield tests.The proposed method can provide a design and use guide to hydraulic oscillators and improve friction reduction effectiveness in horizontal wells.
文摘In this paper the effects of temperature on the radial breathing modes （RBMs） and radial wave propaga- tion in multiwall carbon nanotubes （MWCNTs） are inves- tigated using a continuum model of multiple elastic isotropic shells. The van der Waals forces between tubes are simulated as a nonlinear function of interlayer spacing of MWCNTs. The governing equations are solved using a finite element method. A wide range of innermost radius-to-thickness ratio of MWCNTs is considered to enhance the investigation. The presented solution is verified by comparing the results with those reported in the literature. The effects of temperature on the van der Waals interaction coefficient between layers of MWCNTs are examined. It is found that the variation of the van der Waals interaction coefficient at high temperature is sensible. Subsequently, variations of RBM frequencies and radial wave propagation in MWCNTs with temperatures up to 1 600 K are illustrated. It is shown that the thick MWC- NTs are more sensible to temperature than the thin ones.
文摘A barotropic channel model in β-plane is used to study the effect of topographic forcing on the formation and maintenance of blocking. The approximate analytical solution of potential vorticity equation can show the main property of the whole process of blocking. It is indicated that the topographic forcing is one of the main factors causing the blocking process. The results suggest that the nonlinear interaction plays a very important role in the stable 'Ω' situation of blocking. The atmospheric circulation with periodic and low-frequency oscillation, perhaps, is partly caused by topographic forcing.
