The self-absorption effect is one of the main factors affecting the quantitative analysis accuracy of laser-induced breakdown spectroscopy.In this paper,the self-absorption effects of laserinduced 7050 Al alloy plasma...The self-absorption effect is one of the main factors affecting the quantitative analysis accuracy of laser-induced breakdown spectroscopy.In this paper,the self-absorption effects of laserinduced 7050 Al alloy plasma under different pressures in air,Ar,and N2have been studied.Compared with air and N2,Ar significantly enhances the spectral signal.Furthermore,the spectral self-absorption coefficient is calculated to quantify the degree of self-absorption,and the influences of gas species and gas pressure on self-absorption are analyzed.In addition,it is found that the spectral intensity fluctuates with the change of pressure of three gases.It can also be seen that the fluctuation of spectral intensity with pressure is eliminated after correcting,which indicates that the self-absorption leads to the fluctuation of spectral intensity under different pressures.The analysis shows that the evolution of optical thin spectral lines with pressure in different gases is mainly determined by the gas properties and the competition between plasma confinement and Rayleigh–Taylor instability.展开更多
The structure, electrical transport, and optical properties of GaSe films fabricated by means of radio-frequency (RF) magnetron sputtering in Ar were investigated. The as-sputtered GaSe films were amorphous, and their...The structure, electrical transport, and optical properties of GaSe films fabricated by means of radio-frequency (RF) magnetron sputtering in Ar were investigated. The as-sputtered GaSe films were amorphous, and their optical energy gap Eg are 1.9～2.6 eV. The effect of the synthesis conditions on the optical and electrical properties of the GaSe films has also been展开更多
The Sulagiri meteorite fell in India on 12 September 2008,LL6 chondrite class is the largest among all the Indian meteorites.Isotopic compositions of noble gases(He,Ne,Ar,Kr and Xe) and nitrogen in the Sulagiri meteor...The Sulagiri meteorite fell in India on 12 September 2008,LL6 chondrite class is the largest among all the Indian meteorites.Isotopic compositions of noble gases(He,Ne,Ar,Kr and Xe) and nitrogen in the Sulagiri meteorite and cosmic ray exposure history are discussed.Low cosmogenic(^(22)Ne/^(21)Ne)_c ratio is consistent with irradiation in a large body.Cosmogenic noble gases indicate that Sulagiri has a 4πcosmic-ray exposure(CRE) age of 27.9 ± 3.4 Ma and is a member of the peak of CRE age distribution of IX chondrites.Radiogenic ~4He and ^(40)Ar concentrations in Sulagiri yields the radiogenic ages as 2.29 and4.56 Ca,indicating the loss of He from the meteorite.Xenon and krypton are mixture of Q and spallogenic components.展开更多
ABSTRACT The Raman intensitics of gas molecules were found to be enormously enhanced inthe presence of Hg-microdroplets.The enhancement factor for the molecules studied was foundto be over 20.
The exhaust gases, including SO_2,NH_3, H_2S, NO_2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment.Zeolites have been considered as good absorbent candidates to captur...The exhaust gases, including SO_2,NH_3, H_2S, NO_2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment.Zeolites have been considered as good absorbent candidates to capture the six exhaust gases.In this work, we performed grand canonical ensemble Monte Carlo(GCMC) simulations to examine the capability of 95 kinds of all-silica zeolites in the removal of the six toxic gases, and to predict the adsorption isotherms of the six gases on all the zeolites.The simulation results showed that, H_2S, NO, NO_2, CO and NH_3 are well-captured by zeolite structures with accessible surface area of 1600–1800 m^2·g^(-1) and pore diameter of 0.6–0.7 nm, such as AFY and PAU, while SO_2 is well-adsorbed by zeolites containing larger accessible surface area(1700–2700 m^2·g^(-1)) and pore diameter(0.7–1.4 nm) at room temperature and an atmospheric pressure.However, at saturated adsorption, zeolites RWY, IRR, JSR, TSC, and ITT are found to exhibit better abilities to capture these gases.Our study provides useful computational insights in choosing and designing zeolite structures with high performance to remove toxic gases for air purification, thereby facilitating the development and application of exhaust gas-processing technology in green industry.展开更多
In order to reduce the number of accidents due to explosions of flammable gases in the goaf of coalmines,the conditions for explosion of flammable gases and their explosion limits,affected to a considerable extent by ...In order to reduce the number of accidents due to explosions of flammable gases in the goaf of coalmines,the conditions for explosion of flammable gases and their explosion limits,affected to a considerable extent by CO2,are explored.With the use of our experimental equipment suitable for the study of explosion of polybasic explosive gas mixtures,we investigated the effect of CH4/H2=10/1 and CH4/C2H4=10/1 gases mixed with CO2 on their explosion limits.The results indicate that after adding CO2,the explosion limit of the CH4/H2(or C2H4) =10/1 gas mixtures decreased markedly with increasing amounts of CO2.When the amount of CO2 exceeded 25%,the CH4/C2H4=10/1 flammable gas mixture did not lead to explosions.Similar results were obtained when the amount of CO2 exceeded 23% in the CH4/H2=10/1 flammable gas mixture.We also compared the explosion limits and the explosion suppression effect of N2 or CO2 on the explosion limits of the CH4+CO and CH4+C2H4 dual explosive gas mixtures.Along with the increases in the amounts of CO2 or N2,the area of the explosion limits of gas mixtures decreased.Under the same conditions,the explosion suppression effect of CO2 was greater than that of N2.CO2 has clearly the better suppression effect on the explosion of flammable gases in goafs.展开更多
A unified model for predicting high-pressure viscosities of both hydrocarbon gases and liquids was developed,which is based on the similarity between P-V-T and T-μ-P plots and Patel-Teja equation of state.The charact...A unified model for predicting high-pressure viscosities of both hydrocarbon gases and liquids was developed,which is based on the similarity between P-V-T and T-μ-P plots and Patel-Teja equation of state.The characteristic feature of this new model is its capability of describing the continuous variation of fluid viscosity throughciritical region.The pure component parameters are generalized into functions of reduced temperature,reducedpressure,acentric factor and molecular weight.The overall average absolute deviation of predicted viscositiesof 20 pure hydrocarbon fluids(a total of 1941 data points)is 8.7%.展开更多
We report the experimental realization of quantum degenerate Fermi gases of87Sr atoms under controlled 10-and dual-nuclear-spin configurations.Based on laser cooling and evaporative cooling,we achieve an ultracold Fer...We report the experimental realization of quantum degenerate Fermi gases of87Sr atoms under controlled 10-and dual-nuclear-spin configurations.Based on laser cooling and evaporative cooling,we achieve an ultracold Fermi gas of 105 atoms equally distributed over 10 spin states,with a temperature of T/TF = 0.21.We further prepare a dual-spin gas by optically pumping atoms to the mF = 9/2 and mF = 7/2 states and observe a slightly lower T/TF than that for a 10-spin gas under the same trapping condition,showing efficient evaporative cooling under a decreasing number N of spin states(N≥2)despite the increasing importance of Pauli exclusion.Given that rethermalization becomes less efficient with N approaching unity,we evaporatively cool an almost polarized gas to 130 nK.The simple and efficient preparation of ultracold Fermi gases of 87Sr with tunable spin configurations provides a first step towards engineering topological quantum systems.展开更多
基金National Key Research and Development Program of China(Nos.2017YFE0301306,2017YFE0301300,and 2017YFE0301506)Fujian Province Industrial Guidance Project(No.2019H0011).
文摘The self-absorption effect is one of the main factors affecting the quantitative analysis accuracy of laser-induced breakdown spectroscopy.In this paper,the self-absorption effects of laserinduced 7050 Al alloy plasma under different pressures in air,Ar,and N2have been studied.Compared with air and N2,Ar significantly enhances the spectral signal.Furthermore,the spectral self-absorption coefficient is calculated to quantify the degree of self-absorption,and the influences of gas species and gas pressure on self-absorption are analyzed.In addition,it is found that the spectral intensity fluctuates with the change of pressure of three gases.It can also be seen that the fluctuation of spectral intensity with pressure is eliminated after correcting,which indicates that the self-absorption leads to the fluctuation of spectral intensity under different pressures.The analysis shows that the evolution of optical thin spectral lines with pressure in different gases is mainly determined by the gas properties and the competition between plasma confinement and Rayleigh–Taylor instability.
基金supported by the Federal Target Program“The scientific and Scientific-pedagogical Personnel of Innovative Russia”(No.02.740.11.04444)Russian President Grant(SS4297.2010.2)
基金Supported by RFBR Project(No.10-02-01452-a)Presidium SB RAS under the Project Ⅶ.63.3.1 of Ⅶ.63.3 Prog.Integrated Projec of 2012－2014 and Join Proj. between Presidium SB RAS and Presidium NAS,Belarus No.10 of 2010
文摘The structure, electrical transport, and optical properties of GaSe films fabricated by means of radio-frequency (RF) magnetron sputtering in Ar were investigated. The as-sputtered GaSe films were amorphous, and their optical energy gap Eg are 1.9～2.6 eV. The effect of the synthesis conditions on the optical and electrical properties of the GaSe films has also been
文摘The Sulagiri meteorite fell in India on 12 September 2008,LL6 chondrite class is the largest among all the Indian meteorites.Isotopic compositions of noble gases(He,Ne,Ar,Kr and Xe) and nitrogen in the Sulagiri meteorite and cosmic ray exposure history are discussed.Low cosmogenic(^(22)Ne/^(21)Ne)_c ratio is consistent with irradiation in a large body.Cosmogenic noble gases indicate that Sulagiri has a 4πcosmic-ray exposure(CRE) age of 27.9 ± 3.4 Ma and is a member of the peak of CRE age distribution of IX chondrites.Radiogenic ~4He and ^(40)Ar concentrations in Sulagiri yields the radiogenic ages as 2.29 and4.56 Ca,indicating the loss of He from the meteorite.Xenon and krypton are mixture of Q and spallogenic components.
文摘ABSTRACT The Raman intensitics of gas molecules were found to be enormously enhanced inthe presence of Hg-microdroplets.The enhancement factor for the molecules studied was foundto be over 20.
基金Supported by the National Natural Science Foundation of China(21406172)the Natural Science Foundation of Hubei Province,China(2016CFB388 and 2013CFA091)
文摘The exhaust gases, including SO_2,NH_3, H_2S, NO_2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment.Zeolites have been considered as good absorbent candidates to capture the six exhaust gases.In this work, we performed grand canonical ensemble Monte Carlo(GCMC) simulations to examine the capability of 95 kinds of all-silica zeolites in the removal of the six toxic gases, and to predict the adsorption isotherms of the six gases on all the zeolites.The simulation results showed that, H_2S, NO, NO_2, CO and NH_3 are well-captured by zeolite structures with accessible surface area of 1600–1800 m^2·g^(-1) and pore diameter of 0.6–0.7 nm, such as AFY and PAU, while SO_2 is well-adsorbed by zeolites containing larger accessible surface area(1700–2700 m^2·g^(-1)) and pore diameter(0.7–1.4 nm) at room temperature and an atmospheric pressure.However, at saturated adsorption, zeolites RWY, IRR, JSR, TSC, and ITT are found to exhibit better abilities to capture these gases.Our study provides useful computational insights in choosing and designing zeolite structures with high performance to remove toxic gases for air purification, thereby facilitating the development and application of exhaust gas-processing technology in green industry.
基金provided by the National Natural Science Foundation of China (No.50874088)the Project of Creative Team by the Ministry of Education of China (No.IRT0856)+1 种基金the Excellent Talent Project of the New Century supported by the Ministry of Education of China (No.NECT050874)the Natural Science Foundation of the Education Department of Shaanxi Province (No.08JK351)
文摘In order to reduce the number of accidents due to explosions of flammable gases in the goaf of coalmines,the conditions for explosion of flammable gases and their explosion limits,affected to a considerable extent by CO2,are explored.With the use of our experimental equipment suitable for the study of explosion of polybasic explosive gas mixtures,we investigated the effect of CH4/H2=10/1 and CH4/C2H4=10/1 gases mixed with CO2 on their explosion limits.The results indicate that after adding CO2,the explosion limit of the CH4/H2(or C2H4) =10/1 gas mixtures decreased markedly with increasing amounts of CO2.When the amount of CO2 exceeded 25%,the CH4/C2H4=10/1 flammable gas mixture did not lead to explosions.Similar results were obtained when the amount of CO2 exceeded 23% in the CH4/H2=10/1 flammable gas mixture.We also compared the explosion limits and the explosion suppression effect of N2 or CO2 on the explosion limits of the CH4+CO and CH4+C2H4 dual explosive gas mixtures.Along with the increases in the amounts of CO2 or N2,the area of the explosion limits of gas mixtures decreased.Under the same conditions,the explosion suppression effect of CO2 was greater than that of N2.CO2 has clearly the better suppression effect on the explosion of flammable gases in goafs.
文摘A unified model for predicting high-pressure viscosities of both hydrocarbon gases and liquids was developed,which is based on the similarity between P-V-T and T-μ-P plots and Patel-Teja equation of state.The characteristic feature of this new model is its capability of describing the continuous variation of fluid viscosity throughciritical region.The pure component parameters are generalized into functions of reduced temperature,reducedpressure,acentric factor and molecular weight.The overall average absolute deviation of predicted viscositiesof 20 pure hydrocarbon fluids(a total of 1941 data points)is 8.7%.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0300901 and2018YFA0305601the National Natural Science Foundation of China under Grant No 11874073the International Center for Quantum Materials of Peking University
文摘We report the experimental realization of quantum degenerate Fermi gases of87Sr atoms under controlled 10-and dual-nuclear-spin configurations.Based on laser cooling and evaporative cooling,we achieve an ultracold Fermi gas of 105 atoms equally distributed over 10 spin states,with a temperature of T/TF = 0.21.We further prepare a dual-spin gas by optically pumping atoms to the mF = 9/2 and mF = 7/2 states and observe a slightly lower T/TF than that for a 10-spin gas under the same trapping condition,showing efficient evaporative cooling under a decreasing number N of spin states(N≥2)despite the increasing importance of Pauli exclusion.Given that rethermalization becomes less efficient with N approaching unity,we evaporatively cool an almost polarized gas to 130 nK.The simple and efficient preparation of ultracold Fermi gases of 87Sr with tunable spin configurations provides a first step towards engineering topological quantum systems.
