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Hydrogel-based catalysts for hydrogen generation by the hydrolysis of B–H compounds under external physical fields
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作者 Chunling Qin Wenliu Wu +4 位作者 Hassanien Gomaa Shuai Wu Cuihua An Qibo Deng Ning Hu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第11期518-535,I0011,共19页
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
关键词 HYDROGEL Nanoparticlec atalyst B-H compounds Hydrolysis reaction External physical field
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Analysis of 1989/1990 main physical fields for air-sea coupled system in the tropical western Pacific
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作者 Yao Huadong Jiang Dayong and Liu Yimin Chinese Academy of Meteorological Sciences, Beijing 100081, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1993年第1期93-105,共13页
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
关键词 Analysis of 1989/1990 main physical fields for air-sea coupled system in the tropical western Pacific Nino
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Study on Multi-Scale Tensile Strength and Tensile Strain of Calcium Silicate Hydrate Layered Nanocomposites Under External Physical Field
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作者 Lei FAN Lele ZHANG 《Research and Application of Materials Science》 2023年第1期1-4,共4页
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
关键词 Hydrated calcium silicate External physical field Multiscale Mechanical properties Molecular dynamics
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Electron-positron pair production in ultrastrong laser fields 被引量:5
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作者 Bai Song Xie Zi Liang Li Suo Tang 《Matter and Radiation at Extremes》 SCIE EI CAS 2017年第5期225-242,共18页
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
关键词 Strong field physics Vacuum pair production Nonlinear quantum electrodynamics
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Application of the Physical Quantity Field Evolution under Numerical Model in Precipitation Forecast of Yantai 被引量:1
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作者 SUN Dian-guang,HUANG Ben-feng Yantai Meteorological Bureau in Shandong Province,Yantai 264003,China 《Meteorological and Environmental Research》 CAS 2011年第11期1-4,7,共5页
[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
关键词 Numerical model Evolution of the physical quantity field Application of precipitation forecast China
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HeTDSE:A GPU based program to solve the full-dimensional time-dependent Schr?dinger equation for two-electron helium subjected to strong laser fields
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作者 赵曦 张刚台 +2 位作者 白婷婷 王俊 于伟威 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第7期216-225,共10页
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
关键词 strong field physics TDSE OPENACC GPU electron correlation HELIUM
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Drinking Water Treatment: pH Adjustment Using Natural Physical Field
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作者 Hesham Mohamed Abdal-Salam Yehia Said Mahmoud Said 《Journal of Biosciences and Medicines》 2021年第6期55-66,共12页
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
关键词 ALKALINE ACIDIC Water pH Value BIOTECHNOLOGY physical Field
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Comparative Analysis on Physical Quantity Diagnosis and Wind Profile Radar Data of Two Heavy Rainfalls
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作者 Yunfeng Zhu Mengxi Yang +2 位作者 Jie Liu Beiyuan Wang Haiwei Duo 《Meteorological and Environmental Research》 CAS 2013年第5期9-13,16,共6页
[ 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
关键词 Heavy rainfall Circulation background physical quantity field Wind profile radar China
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Physical Simulation of Nonmetallic Particle Movement in Al Melt under Electromagnetic Field
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作者 Tianxiao LI, Zhenming XU,Baode SUN,Da SHU and Yaohe ZHOU School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第4期463-465,共3页
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
关键词 AL physical Simulation of Nonmetallic Particle Movement in Al Melt under Electromagnetic Field SIMULATION
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辽宁一次大到暴雨天气过程分析(英文) 被引量:2
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作者 李东 许宁 韩蓓蓓 《Meteorological and Environmental Research》 CAS 2010年第9期25-28,共4页
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
关键词 Heavy rain to rainstorm physical quantity field Satellite cloud image Meteorological elements China
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RENEWAL OF BASIC LAWS AND PRINCIPLES FOR POLAR CONTINUUM THEORIES (X) -MASTER BALANCE LAW 被引量:3
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作者 戴天民 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第2期167-174,共8页
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
关键词 unified master balance law physical field quantities conservation laws ENERGY-MOMENTUM energy-angular momentum energy-energy
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Temporal-spatial Distribution and Short-range Prediction Indicators of Hail Weather in East Central Haixi Prefecture of Qinghai Province 被引量:2
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作者 Xiuping Cheng Chengtao Shan +1 位作者 Gasang Pei Na Wang 《Meteorological and Environmental Research》 CAS 2013年第4期21-25,共5页
[ 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
关键词 East central Haixi Prefecture HAIL Temporal-spatial distribution physical quantity field Short-range prediction indicators China
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Theoretical study of the odd-even-order harmonic generation for asymmetric ions in non-Born-Oppenheimer approximation 被引量:1
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作者 岳生俊 杜洪川 +3 位作者 吴红梅 薛山 赵家琛 胡碧涛 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第7期161-166,共6页
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
关键词 strong field physics odd-even-order harmonic dipole acceleration asymmetric ions
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Influence of fault slip on mining-induced pressure and optimization ofroadway support design in fault-influenced zone 被引量:12
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作者 Hongwei Wang Yaodong Jiang +4 位作者 Sheng Xue Lingtao Mao Zhinan Lin Daixin Deng Dengqiang Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2016年第5期660-671,共12页
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
关键词 physical modeling Fault slipMining-induced pressure Roadway support design Field observation
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Analysis of a Rare Continuous Rainy Process in Midsummer 被引量:1
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作者 MA Ling CHEN Ling-ling WANG Xiang 《Meteorological and Environmental Research》 CAS 2011年第8期26-29,共4页
[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
关键词 Continuous rainy weather MIDSUMMER Circulation characteristics physical quantity field Process analysis China
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“海高斯”减弱环流引发的大暴雨天气诊断分析(英文) 被引量:1
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作者 林两位 黄建忠 +1 位作者 王莉萍 洪晓湘 《Meteorological and Environmental Research》 CAS 2010年第10期1-4,7,共5页
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
关键词 Heavy rainstorm physical quantity field Diagnosis and analysis HELICITY China
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张家界2009年12月多次大雾过程对比分析(英文) 被引量:1
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作者 黄骏 梁明增 +3 位作者 刘忠礼 赵英莹 辛学飞 张瑞 《Meteorological and Environmental Research》 CAS 2010年第5期28-31,共4页
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
关键词 Heavy fog Meteorological element Circulation situation physical quantity field China
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Measurement of Electron-Drift Velocity in Ar+CH4 Mixtures Using Double-Grid Method 被引量:1
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作者 张家国 张国辉 陈金象 《Chinese Physics Letters》 SCIE CAS CSCD 2009年第11期41-44,共4页
Based on analyzing the induced signals from the double-grids of an ionization chamber, the electron-drift time between the two grids is determined and the electron-drift velocity is derived. A waveform digitizer is em... Based on analyzing the induced signals from the double-grids of an ionization chamber, the electron-drift time between the two grids is determined and the electron-drift velocity is derived. A waveform digitizer is employed to record pulses from the two grids of the ionization chamber. The electron-drift velocity is measured as a function of the reduced electric field E/p for eight different ratios of Ar+CH4 mixtures. By analyzing the experimental data of this study, self-consistency of experimental data is achieved, and formulae for calculating electron-drift velocity in any ratio of Ar+CH4 mixtures are obtained. 展开更多
关键词 ACCELERATORS beams and electromagnetism Nuclear physics Instrumentation and measurement Plasma physics Particle physics and field theory
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Hyperaccretion after the Blandford-Znajek Process:A New Model for GRBs with X-Ray Flares Observed in Early Afterglows 被引量:1
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作者 Wei-Hua Lei Ding-Xiong Wang Yuan-Chuan Zou Lei Zhang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2008年第4期404-410,共7页
We propose a three-stage model with Blandford-Znajek (BZ) and hyperaccretion process to interpret the recent observations of early afterglows of Gamma-Ray Bursts (GRBs). In the first stage, the prompt GRB is power... We propose a three-stage model with Blandford-Znajek (BZ) and hyperaccretion process to interpret the recent observations of early afterglows of Gamma-Ray Bursts (GRBs). In the first stage, the prompt GRB is powered by a rotating black hole (BH) invoking the BZ process. The second stage is a quiet stage, in which the BZ process is shut off, and the accretion onto the BH is depressed by the torque exerted by the magnetic coupling (MC) process. Part of the rotational energy transported by the MC process from the BH is stored in the disk as magnetic energy. In the third stage, the MC process is shut off when the magnetic energy in the disk accumulates and triggers magnetic instability. At this moment, the hyperaccretion process may set in, and the jet launched in this restarted central engine generates the observed X-ray flares. This model can account for the energies and timescales of GRBs with X-ray flares observed in early afterglows. 展开更多
关键词 accretion accretion disks - black hole physics - magnetic fields - gammarays BURSTS
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Monte Carlo Study on Singly Tagged D Mesons at BES-III 被引量:1
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作者 赵明刚 喻纯旭 李学潜 《Chinese Physics Letters》 SCIE CAS CSCD 2009年第12期64-66,共3页
We present Monte Carlo studies on the singly tagged D mesons, which are crucial in the absolute measurements of D meson decays, based on a full Monte Carlo simulation for the BES-III detector, with the BES-III Offline... We present Monte Carlo studies on the singly tagged D mesons, which are crucial in the absolute measurements of D meson decays, based on a full Monte Carlo simulation for the BES-III detector, with the BES-III Offline Software System. The expected detection efficiencies and mass resolutions of the tagged D mesons are well estimated. 展开更多
关键词 Particle physics and field theory
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