Hydrogen is a popular clean high-energy-density fuel.However,its utilization is limited by the challenges toward low-cost hydrogen production and safe hydrogen storage.Fortunately,these issues can be addressed using p...Hydrogen is a popular clean high-energy-density fuel.However,its utilization is limited by the challenges toward low-cost hydrogen production and safe hydrogen storage.Fortunately,these issues can be addressed using promising hydrogen storage materials such as B–H compounds.Hydrogen stored in B–H compounds can be released by hydrolysis at room temperature,which requires catalysts to increase the rate of the reaction.Recently,several effective approaches have been developed for hydrogen generation by catalyzing the hydrolysis of B–H compounds.This review summarizes the existing research on the use of nanoparticles loaded on hydrogels as catalysts for the hydrolysis of B–H compounds.First,the factors affecting the hydrolysis rate,such as temperature,p H,reactant concentration,and type of nano particles,were investigated.Further,the preparation methods(in situ reduction,one-pot method,template adsorption,etc.)for the hydrogel catalysts and the types of loaded catalysts were determined.Additionally,the hydrogel catalysts that can respond to magnetic fields,ultrasound fields,optical fields,and other physical fields are introduced.Finally,the issues and future developments of hydrogel-based catalysts are discussed.This review can inspire deeper investigations and provide guidance for the study of hydrogel catalysts in the field of hydrogen production via hydrolysis.展开更多
In this paper, the marine ship observation data sets in the seventh (October 16-December 4. 1989) and eighth (June 1-July 16, 1990) cruises of PRC -US tropical ocean and global atmosphere (TOGA) joint scientific inves...In this paper, the marine ship observation data sets in the seventh (October 16-December 4. 1989) and eighth (June 1-July 16, 1990) cruises of PRC -US tropical ocean and global atmosphere (TOGA) joint scientific investigation in the tropical western Pacific are used to analyze the elements such as sea surface temperature (SST), surface wind field, fluxes and net heat budget, which are important physical parameters of underlying earth's surface influencing the global mean circulation evolution on seasonal and interannual time scales. These diagnostic analyses are very beneficial to the understanding of the regional climate characteristics and the air-sea interaction mechanism, and the improving of surface flux parameterizations and regional or global climate model.展开更多
To investigate the differences and the development trends of the 400 kA aluminum reduction cell, four representative cells were deeply analyzed. By using numerical simulation methods in ANSYS software, the structure p...To investigate the differences and the development trends of the 400 kA aluminum reduction cell, four representative cells were deeply analyzed. By using numerical simulation methods in ANSYS software, the structure parameters were firstly compared, and then three-dimensional models of electric-magnetic-flow field were built and solved with finite element method(FEM). The comparison of the structures reveals that the cell bodies are similar while the current flow path and distribution ratio of bus bars are different. It appears that most of the current(70%-80%) in side A are used as the magnetic field compensation current and flow through two ends. The numerical simulation results indicate that the distributions of magnetic fields are different but all satisfy with the magnetohydrodynamics(MHD) stabilization, and the flow patterns are all two or multi vortexes with appropriate velocities. The comparison shows that all studied cells can satisfy with the physical field requirement, and the commercial applications also verify that the 400 kA cells have become the product of the mature and world's leading technology.展开更多
Calcium silicate hydrate(C-S-H)is the mainly strength source of cement-based materials,but there is little basic research.In this paper,molecular dynamics method is applied to analyze the multi-scale tensile strength ...Calcium silicate hydrate(C-S-H)is the mainly strength source of cement-based materials,but there is little basic research.In this paper,molecular dynamics method is applied to analyze the multi-scale tensile strength and tensile strain of C-S-H layered materials under the condition of external physical fields(temperature and strain rate).The results show that the tensile strength and strain of C-S-H model decrease with temperature raises.The temperature(from 1 K to 600 K)has obvious influence on the tensile strain and strength of C-S-H layered materials.In addition,at(0.00025 ps^(-1)-0.001 ps^(-1)),the tensile strain and strength of C-S-H layered materials are less sensitive to strain rate.The whole model is closer to a 3-dimensional deformation.However,at(0.001 ps^(-1)-0.005 ps^(-1)),the dynamic load effect begins to increase,and the work done by the load per unit time increased.The tensile strain and strength of C-S-H layered materials indicates intensified by the change of strain rate.The energies are randomly distributed in the system,not concentrated in a certain area.展开更多
A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and tempera...A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.展开更多
Electronepositron pair production due to the decay of vacuum in ultrastrong laser fields is an interesting topic which is revived recently because of the rapid development of current laser technology.The theoretical a...Electronepositron pair production due to the decay of vacuum in ultrastrong laser fields is an interesting topic which is revived recently because of the rapid development of current laser technology.The theoretical and numerical research progress of this challenging topic is reviewed.Many new findings are presented by different approaches such as the worldline instantons,the S-matrix theory,the kinetic method by solving the quantum Vlasov equation or/and the real-time DiraceHeisenbergeWigner formalism,the computational quantum field theory by solving the Dirac equation and so on.In particular,the effects of electric field polarizations on pair production are unveiled with different patterns of created momentum spectra.The effects of polarizations on the number density of created particles and the nonperturbative signatures of multiphoton process are also presented.The competitive interplay between the multiphoton process and nonperturbation process plays a key role in these new findings.These newly discovered phenomena are valuable to deepen the understanding of pair production in complex fields and even have an implication to the study of strong-field ionization.More recent studies on the pair production in complex fields as well as beyond laser fields are briefly presented in the view point of perspective future.展开更多
[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai durin...[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolution situation.Japan fax chart,European center,MM5,Grapes and T639 could provide future evolution situation of the physical quantity field.[Conclusion] The contrasts and analyses on forecast situations of the physical quantity fields in many precipitation processes showed that evolutions of the vertical velocity,temperature dew point difference,relative humidity and wind field at the different heights could improve forecast accuracy of the precipitation in Yantai.展开更多
Electron–electron correlation plays an important role in the underlying dynamics in physics and chemistry.Helium is the simplest and most fundamental two-electron system.The dynamic process of helium in a strong lase...Electron–electron correlation plays an important role in the underlying dynamics in physics and chemistry.Helium is the simplest and most fundamental two-electron system.The dynamic process of helium in a strong laser field is still a challenging issue because of the large calculation cost.In this study,a graphic processing unit(GPU)open ACC based ab initio numerical simulations package He TDSE is developed to solve the full-dimensional time-dependent Schrodinger equation of helium subjected to a strong laser pulse.He TDSE uses B-spline basis sets expansion method to construct the radial part of the wavefunction,and the spherical harmonic functions is used to express for the angular part.Adams algorithm is employed for the time propagation.Our example shows that He TDSE running on an NVIDIA Kepler K20 GPU can outperform the one on an Intel E5-2640 single CPU core by a factor of 147.He TDSE code package can be obtained from the author or from the author's personal website(doi:10.13140/RG.2.2.15334.45128)directly under the GPL license,so He TDSE can be downloaded,used and modified freely.展开更多
Water has a pH of around (7.0), making it neither alkaline nor acidic. Alkaline is defined as a pH value greater than (7.0). The power of water to neutralize acids is measured by its alkalinity. The pH scale ranges fr...Water has a pH of around (7.0), making it neither alkaline nor acidic. Alkaline is defined as a pH value greater than (7.0). The power of water to neutralize acids is measured by its alkalinity. The pH scale ranges from (pH = 0 to 14), with anything above (pH = 7.0) being alkaline, and anything below (7.0) being acidic. Much of the research up to now has been investigating the effect of adding alkaline substances to the water to increase the pH levels. Recent evidence suggests that using baking soda (sodium bicarbonate), which is an alkaline substance with a pH of about (9). While studies have shown that adding soda to water increases its alkalinity, it has a number of negative health consequences. For instance, Hypokalemia, Hypochloremia, High levels of sodium in the blood, Worsening kidney disease, Worsening heart failure, Muscle weakness and spasm, and Increased stomach acid production. The main aim of this study is to investigate a natural substance consisting of environmental elements i.e., it is derived from silica by the thermal fusion method (prepared by the authors) that raises the pH of water with a physical field of 80 cm without adding any components to the water. The results showed the effectiveness of this natural substance in its solid and liquid forms in raising the pH of water to reach 8.5 from a distance range = 80 cm, without any side effects on human health.展开更多
[ Objective] The research aimed to contrast physical quantity diagnosis and wind profile radar data of two heavy rainfalls. [ Method ] From circulation background, physical quantity field and wind profile radar data, ...[ Objective] The research aimed to contrast physical quantity diagnosis and wind profile radar data of two heavy rainfalls. [ Method ] From circulation background, physical quantity field and wind profile radar data, we analyzed two big rainstorm weather processes （8 -9 July and August 10） in Lianyungang City in 2012. [ Result] Rainstorm generation was related to favorable large-scale circulation situation. The first-stage precipitation during 8 -9 July was warm-zone precipitation, and the precipitation at the second stage was triggered by shear line. Precipitation on August 10 was generated by typhoon low-pressure inverted trough and cold air. Sufficient water vapor content and strong water vapor transportation were favorable for generation of the heavy precipitation. Suction effect by divergence at high layer and convergence at middle and low layers was favorable for maintenance of the strong ascending motion. Occurrence of the heavy precipitation must have ascending motion condition. But it was not that the stronger the ascending motion, the stronger the rainfall intensity. Kindex and θse500 -θse 850 were closely related to rainstorm occurrence. Horizontal wind data of the wind profile radar provided fine structure of the atmospheric horizontal motion at vertical direction, could clearly display vertical structure of the wind field in rainstorm process, and directly reflected change characteristics of the wind field in precipitation process. [ Conclusion] The research could provide reference for future forecast work.展开更多
Physical simulation is used to study the movement of nonmetallic particles in Al melt in electro- magnetic field. It is found that the terminal velocity of particles in different Reynolds number range has different fu...Physical simulation is used to study the movement of nonmetallic particles in Al melt in electro- magnetic field. It is found that the terminal velocity of particles in different Reynolds number range has different functions. By confirming drag force coefficient of nonmetallic particles with Reynolds number in the range of 0.2-10 and 10-25 respectively, two functions of terminal ve- locity for spherical nonmetallic particles have been got accordingly, which provide a theoretical basis for separating nonmetallic inclusions from Al melt in electromagnetic field.展开更多
Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography...Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography theory and Radon inverse transform to derive the expression of the electromagnetic holographic sensitivity field （EMHSF）. Then, we apply the EMHSF calculated by using finite-element methods to flow simulations and holographic imaging. The results suggest that the EMHSF based on the partial derivative of radius of the complex electric potential φ is closely linked to the Radon inverse transform and encompasses the sensitivities of the amplitude and phase data. The flow images obtained with inversion using EMHSF better agree with the actual flow patterns. The EMHSF overcomes the limitations of traditional single-mode sensitivity fields.展开更多
By using the synoptic chart,the physical quantity field,the satellite cloud image and the meteorological elements in the single station,a typical heavy rain to rainstorm weather process which occurred in Liaoning duri...By using the synoptic chart,the physical quantity field,the satellite cloud image and the meteorological elements in the single station,a typical heavy rain to rainstorm weather process which occurred in Liaoning during August 18-20 in 2009 was comprehensively analyzed.The results showed that this process was a weather process which was affected by the upper trough and the subtropical high.Baikal Lake split cold air and Hetao cold air shifted eastward and formed the vortex.The subtropical high extended westward,lifted northward,and the warm wet airflow in the edge cut in.The low-altitude jet stream accelerated the transportation of water vapor,and several active meso-scale convective cloud clusters which appeared in 588 line periphery in the right side of high-altitude jet stream outlet gradually merged with the westerlies system.It caused that the strong mixed precipitation process occurred.展开更多
Through a comparison between the expressions of master balance laws and the conservation laws derived by Noether＇s theorem, a unified master balance law and six physically possible balance equations for micropolar co...Through a comparison between the expressions of master balance laws and the conservation laws derived by Noether＇s theorem, a unified master balance law and six physically possible balance equations for micropolar continuum mechanics are naturally deduced. Among them, by extending the well-known conventional concept of energymomentum tensor, the rather general conservation laws and balance equations named after energy-momentum, energy-angular momentum and energy-energy are obtained. It is clear that the forms of the physical field quantities in the master balance law for the last three cases could not be assumed directly by perceiving through the intuition. Finally, some existing results are reduced immediately as special cases.展开更多
[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six sta...[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six stations in east central Haixi Prefecture from 1960 to 2010, the temporal and spatial distribution of hail weather was analyzed firstly. Afterwards, based on the high-altitude factual data of 30 case studies of hail during 2006 -2010, its high-altitude and ground weather situation and physical quantity field were studied to summarize short-term circulation pattern and shod- range prediction characteristics of hail weather. [ Result] In east central Haixi, hail appeared from April to September, and it was most frequently from May to August. Meanwhile, hail was frequent from 14：00 to 20：00. Among the six stations, hail was most frequent in Tianjun but least frequent in Wulan. Moreover, hail disaster mainly occurred in Wulan and Tianjun. In addition, there were three typos of circulation pattern of hail weather at 500 hPa. Hail mainly occurred under the effect of northwest airflow, and it had shortwave trough, cold center or trough, jet stream core or one of the three. Hail appeared frequently under the situation of upper-level divergence and low-level convergence, and abundant water vapor and water vapor flux convergence at low levels were important conditions for hailing. [ Conclusion] The research could provide scientific references for improving the accuracy of hail forecast.展开更多
We calculated the harmonic spectra generated from the asymmetric molecules of HD^＋ and HeH^2＋. It is found that HD＋produces only odd harmonics, while HeH^2＋produces both odd and even harmonics. Further analysis re...We calculated the harmonic spectra generated from the asymmetric molecules of HD^＋ and HeH^2＋. It is found that HD＋produces only odd harmonics, while HeH^2＋produces both odd and even harmonics. Further analysis reveals that for both HD^＋ and HeH^2＋, the nuclear dipole acceleration can generate even harmonics, but it is three orders of magnitude lower than that of the electron. Hence, the electronic dipole acceleration dominates the harmonic generation. For HD^＋,the electronic dipole acceleration only contributes to the generation of odd harmonics, but for HeH^2＋it contributes to the generation of both odd and even harmonics. Besides, one concept of the broken degree of system-symmetry is proposed to explain the different odd-even property between the harmonic spectra of HD^＋ and HeH^2＋.展开更多
This paper presents an investigation on the characteristics of overlying strata collapse and mining-induced pressure in fault-influenced zone by employing the physical modeling in consideration of fault structure. The...This paper presents an investigation on the characteristics of overlying strata collapse and mining-induced pressure in fault-influenced zone by employing the physical modeling in consideration of fault structure. The precursory information of fault slip during the underground mining activities is studied as well. Based on the physical modeling, the optimization of roadway support design and the field verification in fault-influenced zone are conducted. Physical modeling results show that, due to the combined effect of mining activities and fault slip, the mining-induced pressure and the extent of damaged rock masses in the fault-influenced zone are greater than those in the uninfluenced zone. The sharp increase and the succeeding stabilization of stress or steady increase in displacement can be identified as the precursory information of fault slip. Considering the larger mining-induced pressure in the fault-influenced zone, the new support design utilizing cables is proposed. The optimization of roadway support design suggests that the cables can be anchored in the stable surrounding rocks and can effectively mobilize the load bearing capacity of the stable surrounding rocks. The field observation indicates that the roadway is in good condition with the optimized roadway support design.展开更多
[Objective] The research aimed to analyze a rare low temperature and rainy weather process which happened in Anhui Province from July 22 to August 14,2009.[Method] Based on the data of conventional observation,NCEP an...[Objective] The research aimed to analyze a rare low temperature and rainy weather process which happened in Anhui Province from July 22 to August 14,2009.[Method] Based on the data of conventional observation,NCEP analysis field and automatic station,a rare low temperature and rainy weather process which occurred in Anhui Province from July 22 to August 14,2009 was analyzed.The formation reason of continuous rainy process in midsummer was discussed.The circulation characteristics and influence systems of continuous rainy process were revealed.On the base,the influences of configuration of circulation fields and difference of physical quantity fields at high and low layers on range and intensity of precipitation were analyzed.[Result] According to the circulation situation and influence system,the continuous rainy process could be divided into four stages:July 22-24,from July 27 to August 1,August 4-8 and August 9-14.Moreover,it was respectively affected by northeast low vortex,cold and warm air,high-level low trough,typhoon and periphery of subtropical high at four stages.The maintenance of big specific humidity zone provided sufficient water vapor condition for the continuous rainy weather.The rainstorm appeared in dense zone of specific humidity line,where the specific humidity >13 g/kg in the humidity front zone.A temperature trough maintained at 850 hPa.The cold air which continued to diffuse and go south was main reason of the abnormally low temperature during the continuous rainy period.Moreover,it provided ascending motion condition for precipitation maintenance.[Conclusion] The research provided references for actual forecast of continuous rainy weather.展开更多
The large-range heavy precipitation occurred in the central-southern coast of Fujian on October 6,2008.By using the conventional meteorological data and NCEP 1°×1° 6 h one time analysis data,we analyzed...The large-range heavy precipitation occurred in the central-southern coast of Fujian on October 6,2008.By using the conventional meteorological data and NCEP 1°×1° 6 h one time analysis data,we analyzed,diagnosed and discussed the reasons of this heavy rainstorm occurrence and maintenance.The results showed that this heavy rainstorm weather process was mainly formed by the low-pressure system which was remained after ' Higos' weakened.The low-pressure system was excited by the weak cold air in the low layer which was brought by 500 hPa westerly trough.The common effect of southwest jet stream in the low altitude in the southeast of low pressure and the northerly airflow in the northwest made that the low-pressure circulation strengthened and maintained.The calculation gained the physical quantity field configuration which was favorable for the appearance of heavy precipitation.The analysis on the relative helicity of windstorm showed that the distribution and the time evolution of helicity had the good corresponding relationship with the distribution and the time evolution of heavy precipitation.The intensity variation of helicity had the certain instruction significance on the rainstorm evolution.展开更多
By using the observation data,routine data and NCEP reanalysis data in the automatic station,5 times heavy fog weather processes in Zhangjiajie City in December,2009 were contrasted and analyzed.The results showed tha...By using the observation data,routine data and NCEP reanalysis data in the automatic station,5 times heavy fog weather processes in Zhangjiajie City in December,2009 were contrasted and analyzed.The results showed that 3 conditions were the essential conditions of heavy fog occurrence in Zhangjiajie area.3 conditions were that the wind speed was during 0.1-3.0 m/s,the relative humidity ≥90% and the depression of dew point ΔT ≤1.5 ℃.The fog concentration had no positive correlation relationship with the above conditions.The accumulation of humidity condition in the previous period was also the main reason which affected the generation of heavy fog.The physical quantity field which related to the stability and the relative humidity field which related to the water vapor condition had the certain directive significance for forecasting the heavy fog weather.The fog concentration presented the positive correlation relationship with the inversion intensity.展开更多
基金supported by National Natural Science Fund of China(Grant No.12172118,52071125)the Research Program of Local Science and Technology Development under the Guidance of Central(216Z4402G)+1 种基金Science and Technology Project of Hebei Education Department(BJK2022015)support from“Yuanguang”Scholar Program of Hebei University of Technology。
文摘Hydrogen is a popular clean high-energy-density fuel.However,its utilization is limited by the challenges toward low-cost hydrogen production and safe hydrogen storage.Fortunately,these issues can be addressed using promising hydrogen storage materials such as B–H compounds.Hydrogen stored in B–H compounds can be released by hydrolysis at room temperature,which requires catalysts to increase the rate of the reaction.Recently,several effective approaches have been developed for hydrogen generation by catalyzing the hydrolysis of B–H compounds.This review summarizes the existing research on the use of nanoparticles loaded on hydrogels as catalysts for the hydrolysis of B–H compounds.First,the factors affecting the hydrolysis rate,such as temperature,p H,reactant concentration,and type of nano particles,were investigated.Further,the preparation methods(in situ reduction,one-pot method,template adsorption,etc.)for the hydrogel catalysts and the types of loaded catalysts were determined.Additionally,the hydrogel catalysts that can respond to magnetic fields,ultrasound fields,optical fields,and other physical fields are introduced.Finally,the issues and future developments of hydrogel-based catalysts are discussed.This review can inspire deeper investigations and provide guidance for the study of hydrogel catalysts in the field of hydrogen production via hydrolysis.
文摘In this paper, the marine ship observation data sets in the seventh (October 16-December 4. 1989) and eighth (June 1-July 16, 1990) cruises of PRC -US tropical ocean and global atmosphere (TOGA) joint scientific investigation in the tropical western Pacific are used to analyze the elements such as sea surface temperature (SST), surface wind field, fluxes and net heat budget, which are important physical parameters of underlying earth's surface influencing the global mean circulation evolution on seasonal and interannual time scales. These diagnostic analyses are very beneficial to the understanding of the regional climate characteristics and the air-sea interaction mechanism, and the improving of surface flux parameterizations and regional or global climate model.
基金Projects(51104187,51274241,61321003) supported by the National Natural Science Foundation of ChinaProject(20100162120008) supported by Doctoral Fund of Ministry of Education of China
文摘To investigate the differences and the development trends of the 400 kA aluminum reduction cell, four representative cells were deeply analyzed. By using numerical simulation methods in ANSYS software, the structure parameters were firstly compared, and then three-dimensional models of electric-magnetic-flow field were built and solved with finite element method(FEM). The comparison of the structures reveals that the cell bodies are similar while the current flow path and distribution ratio of bus bars are different. It appears that most of the current(70%-80%) in side A are used as the magnetic field compensation current and flow through two ends. The numerical simulation results indicate that the distributions of magnetic fields are different but all satisfy with the magnetohydrodynamics(MHD) stabilization, and the flow patterns are all two or multi vortexes with appropriate velocities. The comparison shows that all studied cells can satisfy with the physical field requirement, and the commercial applications also verify that the 400 kA cells have become the product of the mature and world's leading technology.
基金This work was supported by a Natural Science Foundation of Zhejiang Province(LQ23E080003)Innovative training program for college students.
文摘Calcium silicate hydrate(C-S-H)is the mainly strength source of cement-based materials,but there is little basic research.In this paper,molecular dynamics method is applied to analyze the multi-scale tensile strength and tensile strain of C-S-H layered materials under the condition of external physical fields(temperature and strain rate).The results show that the tensile strength and strain of C-S-H model decrease with temperature raises.The temperature(from 1 K to 600 K)has obvious influence on the tensile strain and strength of C-S-H layered materials.In addition,at(0.00025 ps^(-1)-0.001 ps^(-1)),the tensile strain and strength of C-S-H layered materials are less sensitive to strain rate.The whole model is closer to a 3-dimensional deformation.However,at(0.001 ps^(-1)-0.005 ps^(-1)),the dynamic load effect begins to increase,and the work done by the load per unit time increased.The tensile strain and strength of C-S-H layered materials indicates intensified by the change of strain rate.The energies are randomly distributed in the system,not concentrated in a certain area.
文摘A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.
基金This work was supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.11475026,11175023also supported partially by the Open Fund of National Laboratory of Science and Technology on Computational Physics at IAPCM and the Fundamental Research Funds for the Central Universities(FRFCU).
文摘Electronepositron pair production due to the decay of vacuum in ultrastrong laser fields is an interesting topic which is revived recently because of the rapid development of current laser technology.The theoretical and numerical research progress of this challenging topic is reviewed.Many new findings are presented by different approaches such as the worldline instantons,the S-matrix theory,the kinetic method by solving the quantum Vlasov equation or/and the real-time DiraceHeisenbergeWigner formalism,the computational quantum field theory by solving the Dirac equation and so on.In particular,the effects of electric field polarizations on pair production are unveiled with different patterns of created momentum spectra.The effects of polarizations on the number density of created particles and the nonperturbative signatures of multiphoton process are also presented.The competitive interplay between the multiphoton process and nonperturbation process plays a key role in these new findings.These newly discovered phenomena are valuable to deepen the understanding of pair production in complex fields and even have an implication to the study of strong-field ionization.More recent studies on the pair production in complex fields as well as beyond laser fields are briefly presented in the view point of perspective future.
文摘[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolution situation.Japan fax chart,European center,MM5,Grapes and T639 could provide future evolution situation of the physical quantity field.[Conclusion] The contrasts and analyses on forecast situations of the physical quantity fields in many precipitation processes showed that evolutions of the vertical velocity,temperature dew point difference,relative humidity and wind field at the different heights could improve forecast accuracy of the precipitation in Yantai.
基金the National Natural Science Foundation of China(Grant Nos.11904192,11604119,11627807,and 11604131)the Natural Science Basic Research Plan of Shaanxi Province of China(Grant No.2016JM1012)+2 种基金the Natural Science Foundation of the Education Committee of Shaanxi Province of China(Grant No.18JK0050)the Science Foundation of Baoji University of Arts and Sciences of China(Grant No.ZK16069)the Natural Science Foundation of Liaoning Province of China(Grant No.LQ 2020022)。
文摘Electron–electron correlation plays an important role in the underlying dynamics in physics and chemistry.Helium is the simplest and most fundamental two-electron system.The dynamic process of helium in a strong laser field is still a challenging issue because of the large calculation cost.In this study,a graphic processing unit(GPU)open ACC based ab initio numerical simulations package He TDSE is developed to solve the full-dimensional time-dependent Schrodinger equation of helium subjected to a strong laser pulse.He TDSE uses B-spline basis sets expansion method to construct the radial part of the wavefunction,and the spherical harmonic functions is used to express for the angular part.Adams algorithm is employed for the time propagation.Our example shows that He TDSE running on an NVIDIA Kepler K20 GPU can outperform the one on an Intel E5-2640 single CPU core by a factor of 147.He TDSE code package can be obtained from the author or from the author's personal website(doi:10.13140/RG.2.2.15334.45128)directly under the GPL license,so He TDSE can be downloaded,used and modified freely.
文摘Water has a pH of around (7.0), making it neither alkaline nor acidic. Alkaline is defined as a pH value greater than (7.0). The power of water to neutralize acids is measured by its alkalinity. The pH scale ranges from (pH = 0 to 14), with anything above (pH = 7.0) being alkaline, and anything below (7.0) being acidic. Much of the research up to now has been investigating the effect of adding alkaline substances to the water to increase the pH levels. Recent evidence suggests that using baking soda (sodium bicarbonate), which is an alkaline substance with a pH of about (9). While studies have shown that adding soda to water increases its alkalinity, it has a number of negative health consequences. For instance, Hypokalemia, Hypochloremia, High levels of sodium in the blood, Worsening kidney disease, Worsening heart failure, Muscle weakness and spasm, and Increased stomach acid production. The main aim of this study is to investigate a natural substance consisting of environmental elements i.e., it is derived from silica by the thermal fusion method (prepared by the authors) that raises the pH of water with a physical field of 80 cm without adding any components to the water. The results showed the effectiveness of this natural substance in its solid and liquid forms in raising the pH of water to reach 8.5 from a distance range = 80 cm, without any side effects on human health.
基金Supported by Social Development Fund Project of the Science and Technology Bureau in Lianyungang City,China ( SH1207)
文摘[ Objective] The research aimed to contrast physical quantity diagnosis and wind profile radar data of two heavy rainfalls. [ Method ] From circulation background, physical quantity field and wind profile radar data, we analyzed two big rainstorm weather processes （8 -9 July and August 10） in Lianyungang City in 2012. [ Result] Rainstorm generation was related to favorable large-scale circulation situation. The first-stage precipitation during 8 -9 July was warm-zone precipitation, and the precipitation at the second stage was triggered by shear line. Precipitation on August 10 was generated by typhoon low-pressure inverted trough and cold air. Sufficient water vapor content and strong water vapor transportation were favorable for generation of the heavy precipitation. Suction effect by divergence at high layer and convergence at middle and low layers was favorable for maintenance of the strong ascending motion. Occurrence of the heavy precipitation must have ascending motion condition. But it was not that the stronger the ascending motion, the stronger the rainfall intensity. Kindex and θse500 -θse 850 were closely related to rainstorm occurrence. Horizontal wind data of the wind profile radar provided fine structure of the atmospheric horizontal motion at vertical direction, could clearly display vertical structure of the wind field in rainstorm process, and directly reflected change characteristics of the wind field in precipitation process. [ Conclusion] The research could provide reference for future forecast work.
基金supported by the National Natural Science Foundation of China(No.59871029)the China Postdoctoral Science Foundation.
文摘Physical simulation is used to study the movement of nonmetallic particles in Al melt in electro- magnetic field. It is found that the terminal velocity of particles in different Reynolds number range has different functions. By confirming drag force coefficient of nonmetallic particles with Reynolds number in the range of 0.2-10 and 10-25 respectively, two functions of terminal ve- locity for spherical nonmetallic particles have been got accordingly, which provide a theoretical basis for separating nonmetallic inclusions from Al melt in electromagnetic field.
基金supported by the National Science and Technology Major Project(No.2011ZX05020-006)
文摘Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography theory and Radon inverse transform to derive the expression of the electromagnetic holographic sensitivity field （EMHSF）. Then, we apply the EMHSF calculated by using finite-element methods to flow simulations and holographic imaging. The results suggest that the EMHSF based on the partial derivative of radius of the complex electric potential φ is closely linked to the Radon inverse transform and encompasses the sensitivities of the amplitude and phase data. The flow images obtained with inversion using EMHSF better agree with the actual flow patterns. The EMHSF overcomes the limitations of traditional single-mode sensitivity fields.
文摘By using the synoptic chart,the physical quantity field,the satellite cloud image and the meteorological elements in the single station,a typical heavy rain to rainstorm weather process which occurred in Liaoning during August 18-20 in 2009 was comprehensively analyzed.The results showed that this process was a weather process which was affected by the upper trough and the subtropical high.Baikal Lake split cold air and Hetao cold air shifted eastward and formed the vortex.The subtropical high extended westward,lifted northward,and the warm wet airflow in the edge cut in.The low-altitude jet stream accelerated the transportation of water vapor,and several active meso-scale convective cloud clusters which appeared in 588 line periphery in the right side of high-altitude jet stream outlet gradually merged with the westerlies system.It caused that the strong mixed precipitation process occurred.
基金Project supported by the National Natural Science Foundation of China (Nos.10072024 and 10472041)
文摘Through a comparison between the expressions of master balance laws and the conservation laws derived by Noether＇s theorem, a unified master balance law and six physically possible balance equations for micropolar continuum mechanics are naturally deduced. Among them, by extending the well-known conventional concept of energymomentum tensor, the rather general conservation laws and balance equations named after energy-momentum, energy-angular momentum and energy-energy are obtained. It is clear that the forms of the physical field quantities in the master balance law for the last three cases could not be assumed directly by perceiving through the intuition. Finally, some existing results are reduced immediately as special cases.
文摘[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six stations in east central Haixi Prefecture from 1960 to 2010, the temporal and spatial distribution of hail weather was analyzed firstly. Afterwards, based on the high-altitude factual data of 30 case studies of hail during 2006 -2010, its high-altitude and ground weather situation and physical quantity field were studied to summarize short-term circulation pattern and shod- range prediction characteristics of hail weather. [ Result] In east central Haixi, hail appeared from April to September, and it was most frequently from May to August. Meanwhile, hail was frequent from 14：00 to 20：00. Among the six stations, hail was most frequent in Tianjun but least frequent in Wulan. Moreover, hail disaster mainly occurred in Wulan and Tianjun. In addition, there were three typos of circulation pattern of hail weather at 500 hPa. Hail mainly occurred under the effect of northwest airflow, and it had shortwave trough, cold center or trough, jet stream core or one of the three. Hail appeared frequently under the situation of upper-level divergence and low-level convergence, and abundant water vapor and water vapor flux convergence at low levels were important conditions for hailing. [ Conclusion] The research could provide scientific references for improving the accuracy of hail forecast.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404153,11135002,11475076,and 11405077)the Fundamental Research Funds for the Central Universities of China(Grants Nos.lzujbky-2016-29,lzujbky-2016-31,and lzujbky-2016-209)
文摘We calculated the harmonic spectra generated from the asymmetric molecules of HD^＋ and HeH^2＋. It is found that HD＋produces only odd harmonics, while HeH^2＋produces both odd and even harmonics. Further analysis reveals that for both HD^＋ and HeH^2＋, the nuclear dipole acceleration can generate even harmonics, but it is three orders of magnitude lower than that of the electron. Hence, the electronic dipole acceleration dominates the harmonic generation. For HD^＋,the electronic dipole acceleration only contributes to the generation of odd harmonics, but for HeH^2＋it contributes to the generation of both odd and even harmonics. Besides, one concept of the broken degree of system-symmetry is proposed to explain the different odd-even property between the harmonic spectra of HD^＋ and HeH^2＋.
基金financially supported by the National Natural Science Foundation of China(No.41502184)Beijing Natural Science Foundation(No.2164067)+2 种基金National Key Research and Development Program(No.2016YFC0801401)Fundamental Research Funds for the Central Universities(No.2014QL01)Innovation Training Programs for Undergraduate Students(Nos.201411413054 and SKLCRSM14CXJH08)
文摘This paper presents an investigation on the characteristics of overlying strata collapse and mining-induced pressure in fault-influenced zone by employing the physical modeling in consideration of fault structure. The precursory information of fault slip during the underground mining activities is studied as well. Based on the physical modeling, the optimization of roadway support design and the field verification in fault-influenced zone are conducted. Physical modeling results show that, due to the combined effect of mining activities and fault slip, the mining-induced pressure and the extent of damaged rock masses in the fault-influenced zone are greater than those in the uninfluenced zone. The sharp increase and the succeeding stabilization of stress or steady increase in displacement can be identified as the precursory information of fault slip. Considering the larger mining-induced pressure in the fault-influenced zone, the new support design utilizing cables is proposed. The optimization of roadway support design suggests that the cables can be anchored in the stable surrounding rocks and can effectively mobilize the load bearing capacity of the stable surrounding rocks. The field observation indicates that the roadway is in good condition with the optimized roadway support design.
文摘[Objective] The research aimed to analyze a rare low temperature and rainy weather process which happened in Anhui Province from July 22 to August 14,2009.[Method] Based on the data of conventional observation,NCEP analysis field and automatic station,a rare low temperature and rainy weather process which occurred in Anhui Province from July 22 to August 14,2009 was analyzed.The formation reason of continuous rainy process in midsummer was discussed.The circulation characteristics and influence systems of continuous rainy process were revealed.On the base,the influences of configuration of circulation fields and difference of physical quantity fields at high and low layers on range and intensity of precipitation were analyzed.[Result] According to the circulation situation and influence system,the continuous rainy process could be divided into four stages:July 22-24,from July 27 to August 1,August 4-8 and August 9-14.Moreover,it was respectively affected by northeast low vortex,cold and warm air,high-level low trough,typhoon and periphery of subtropical high at four stages.The maintenance of big specific humidity zone provided sufficient water vapor condition for the continuous rainy weather.The rainstorm appeared in dense zone of specific humidity line,where the specific humidity >13 g/kg in the humidity front zone.A temperature trough maintained at 850 hPa.The cold air which continued to diffuse and go south was main reason of the abnormally low temperature during the continuous rainy period.Moreover,it provided ascending motion condition for precipitation maintenance.[Conclusion] The research provided references for actual forecast of continuous rainy weather.
文摘The large-range heavy precipitation occurred in the central-southern coast of Fujian on October 6,2008.By using the conventional meteorological data and NCEP 1°×1° 6 h one time analysis data,we analyzed,diagnosed and discussed the reasons of this heavy rainstorm occurrence and maintenance.The results showed that this heavy rainstorm weather process was mainly formed by the low-pressure system which was remained after ' Higos' weakened.The low-pressure system was excited by the weak cold air in the low layer which was brought by 500 hPa westerly trough.The common effect of southwest jet stream in the low altitude in the southeast of low pressure and the northerly airflow in the northwest made that the low-pressure circulation strengthened and maintained.The calculation gained the physical quantity field configuration which was favorable for the appearance of heavy precipitation.The analysis on the relative helicity of windstorm showed that the distribution and the time evolution of helicity had the good corresponding relationship with the distribution and the time evolution of heavy precipitation.The intensity variation of helicity had the certain instruction significance on the rainstorm evolution.
文摘By using the observation data,routine data and NCEP reanalysis data in the automatic station,5 times heavy fog weather processes in Zhangjiajie City in December,2009 were contrasted and analyzed.The results showed that 3 conditions were the essential conditions of heavy fog occurrence in Zhangjiajie area.3 conditions were that the wind speed was during 0.1-3.0 m/s,the relative humidity ≥90% and the depression of dew point ΔT ≤1.5 ℃.The fog concentration had no positive correlation relationship with the above conditions.The accumulation of humidity condition in the previous period was also the main reason which affected the generation of heavy fog.The physical quantity field which related to the stability and the relative humidity field which related to the water vapor condition had the certain directive significance for forecasting the heavy fog weather.The fog concentration presented the positive correlation relationship with the inversion intensity.
