Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature a...Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature and atmospheric composition.However,the existing parameters for mechanism interpretation are derived from the traditional smog chambers.To address the gap between the traditional laboratory simulations and the photochemistry in the real atmosphere,a vehicle-mounted indoor-outdoor dual-smog chamber(JNUVMDSC)was developed,which can be quickly transferred to the desired sites to simulate quasi-realistic atmosphere simultaneously in both chambers using“local air”.Multiple key parameters of the smog chamber were characterized in the study,demonstrating that JNUVMDSC meets the requirements of general atmospheric chemistry simulation studies.Additionally,the preliminary results for the photochemical simulations of quasi-realistic atmospheres in Pearl River Delta region and Nanling Mountains are consistent with literature reports on the photochemistry in this region.JNU-VMDSC provides a convenient and reliable experimental device and means to study the mechanism of atmospheric photochemical reactions to obtain near-real results,and will make a great contribution to the control of composite air pollution.展开更多
This paper deals with investigations on corrosion of marble SO2. We have simulated oxidation of SO2 by photochemical process in the atmosphere. The experiments indicate that formation of SO3 aerosols is related to the...This paper deals with investigations on corrosion of marble SO2. We have simulated oxidation of SO2 by photochemical process in the atmosphere. The experiments indicate that formation of SO3 aerosols is related to the concentration of SO2, the UV light intensity, the time of irradiation and the humidity of the air. The corrosion feature of surfaces of the marble and the depth profiles of sulphur were obtained by SEM (Scanning electron microscope), EDXA (Energy-dispersive X-ray analyzer) and SIMS (Secondary ion mass spectrometer). The results of experiments show the corrosive extent of marble depends on its compositions and microareas of marble, which contain lower silicon content can be easily corroded by SO2.展开更多
Populus euphratica Oliv.is a unique woody tree that can be utilized for vegetation restoration in arid and semi-arid areas.The effects of saline water irrigation(0.00, 2.93, 8.78 and 17.55 g/L NaCl solutions) on water...Populus euphratica Oliv.is a unique woody tree that can be utilized for vegetation restoration in arid and semi-arid areas.The effects of saline water irrigation(0.00, 2.93, 8.78 and 17.55 g/L NaCl solutions) on water transport and water use efficiency(WUE) of P.euphratica saplings were researched for improving the survival of P.euphratica saplings and vegetation restoration in arid and semi-arid areas of Xinjiang, China in 2011.Results showed that hydraulic conductivity and vulnerability to cavitation of P.euphratica saplings were more sensitive in root xylem than in twig xylem when irrigation water salinity increased.Irrigation with saline water concentration less than 8.78 g/L did not affect the growth of P.euphratica saplings, under which they maintained normal water transport in twig xylem through adjustment of anatomical structure of vessels and kept higher WUE and photosynthesis in leaves through adjustment of stomata.However, irrigation with saline water concentration up to 17.55 g/L severely inhibited the photochemical process and WUE of P.euphratica saplings, resulting in severe water-deficit in leaves and a sharp reduction in water transport in xylem.Thus, it is feasible to irrigate P.euphratica forest by using saline groundwater for improving the survival of P.euphratica saplings and vegetation restoration in arid and semi-arid areas of Xinjiang, China.展开更多
Investigation of the distribution,evolution,and interactions of atmospheric components on Mars is crucial for understanding its climate and environment.The Spectroscopy Spectrograph for the Investigation of Characteri...Investigation of the distribution,evolution,and interactions of atmospheric components on Mars is crucial for understanding its climate and environment.The Spectroscopy Spectrograph for the Investigation of Characteristics of the Atmosphere of Mars(SPICAM),an instrument on the Mars Express spacecraft launched by the European Space Agency,consists of an ultraviolet channel(118–320 nm)and a near-infrared channel(1000–1700 nm),which provides the most comprehensive vertical spectral dataset of the Martian atmosphere to date.This study analyzes the spectral data obtained from nadir observations of SPICAM's infrared channel during its first operational Martian year(January 2004 to November 2005)on the basis of the spectral theory of O_(2)molecular airglow and the radiative transfer mechanism of H2O in the atmosphere,retrieving the seasonal and global distributions of O_(2)(a^(1)△_(g))airglow intensity and H2O abundance.Results reveal a clear inverse correlation between O_(2)(a^(1)△_(g))airglow intensity and H2O abundance.This finding provides indirect evidence of an anticorrelation between O3 and H2O,given that O_(2)(a^(1)△_(g))airglow serves as a tracer for O3 photodissociation.This will contribute to a deeper understanding of Martian climatology,thereby further refining Martian photochemical models,and assisting in exploring the stability of the Martian atmosphere.展开更多
Our analysis of the surface aerosol and ultraviolet （UV） measurements in Pearl River Delta （PRD） region shows that the surface UV radiation is reduced by more than 50% due to high aerosol concentrations. This has ...Our analysis of the surface aerosol and ultraviolet （UV） measurements in Pearl River Delta （PRD） region shows that the surface UV radiation is reduced by more than 50% due to high aerosol concentrations. This has important impacts on urban ecosystem and photochemistry, especially on ozone photochemical production over the region. The quantitative effect of aerosols on surface ozone is evaluated by analyzing surface observations （including ozone, ultraviolet radiation, aerosol radiative parameters） and by using radiative and chemical models. A case study shows that the aerosol concentrations and UV radiation are significantly correlated with ozone concentrations. The correlation coefficient between the aerosol optical depth （AOD） and the PM10 mass concentration is very high, with a maximum of 0.98, and the AOD and UV radiation/ozone is anti- correlated, with a correlation coefficient of-0.90. The analysis suggests that ozone productivity is significantly decreased due to the reduction of UV radiation. The noon-time ozone maximum is considerably depressed when AOD is 0.6, and is further decreased when AOD is up to 1.2 due to the reduction of ozone photochemical productivity. Because the occurring probability of aerosol optical depth for AOD550m≥0.6 and AOD340mm ≥1.0 is 47, and 55% respectively during the dry season （October, November, December, January）, this heavy aerosol condition explains the low ozone maximum that often occurs in the dry season over the Guangzhou region. The analysis also suggests that the value of single scattering albedo （SSA） is very sensitive to the aerosol radiative effect when the radiative and chemical models are applied, implying that the value of SSA needs to be carefully studied when the models are used in calculating ozone production.展开更多
In order to obtain inexpensive and effective application of catalyst for photodegradation,Cu_(2)O powder was prepared by the simple and inexpensive electrodeposition method using surfactants such as glycerin(GLY),poly...In order to obtain inexpensive and effective application of catalyst for photodegradation,Cu_(2)O powder was prepared by the simple and inexpensive electrodeposition method using surfactants such as glycerin(GLY),polyvinyl alcohol(PVA),poly(N-vinylpyrrolidone)(PVP)that helped the growth and nucleation of suspended particles.These particles were distinguished by atomic force microscopy(AFM),X-ray diffraction(XRD),field-emission scanning electron microscopy(FESEM)and high-resolution transmission electron microscopy(HRTEM).Diameter size of these obtained particles was found to reach to about 40 nm.In order to demonstrate the photodegradation efficiency of the copper oxide in the removal of organic malachite green oxalate(MG)dye,the catalyst was used both in calcination at 300°C and without calcination.Parameters such as the amount of catalyst,the concentration of dye,the pH of dye sol,and the temperature were calculated.Pseudo first order reactions according to Langmuir-Hinshelwood kinetics could be obtained from the result of photocatalytic reactions.Parameters such as energy activation(Ea),enthalpy of activation(ΔH0),entropy of activation(ΔS0)and free energy of activation(ΔG0)were calculated.The activation energy was equal to 11.719±1 and 11.083±1 kJ/mol for MG dye in the presence of Cu_(2)O nanoparticles in both two cases of calcination and without calcination respectively.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.41877370 and 42077190)the China Postdoctoral Science Foundation(No.2021M691229)+2 种基金the fund of Creative Research Groups of NSFC(No.42121004)the Science and Technology Planning Project of Guangdong Province of China(No.2019B121202002)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06N263).
文摘Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature and atmospheric composition.However,the existing parameters for mechanism interpretation are derived from the traditional smog chambers.To address the gap between the traditional laboratory simulations and the photochemistry in the real atmosphere,a vehicle-mounted indoor-outdoor dual-smog chamber(JNUVMDSC)was developed,which can be quickly transferred to the desired sites to simulate quasi-realistic atmosphere simultaneously in both chambers using“local air”.Multiple key parameters of the smog chamber were characterized in the study,demonstrating that JNUVMDSC meets the requirements of general atmospheric chemistry simulation studies.Additionally,the preliminary results for the photochemical simulations of quasi-realistic atmospheres in Pearl River Delta region and Nanling Mountains are consistent with literature reports on the photochemistry in this region.JNU-VMDSC provides a convenient and reliable experimental device and means to study the mechanism of atmospheric photochemical reactions to obtain near-real results,and will make a great contribution to the control of composite air pollution.
文摘This paper deals with investigations on corrosion of marble SO2. We have simulated oxidation of SO2 by photochemical process in the atmosphere. The experiments indicate that formation of SO3 aerosols is related to the concentration of SO2, the UV light intensity, the time of irradiation and the humidity of the air. The corrosion feature of surfaces of the marble and the depth profiles of sulphur were obtained by SEM (Scanning electron microscope), EDXA (Energy-dispersive X-ray analyzer) and SIMS (Secondary ion mass spectrometer). The results of experiments show the corrosive extent of marble depends on its compositions and microareas of marble, which contain lower silicon content can be easily corroded by SO2.
基金funded by the National Natural Science Foundation of China (U1703101, U1803101)the Science and the Strategic Priority Research Program of Chinese Academy of Sciences (XDA20100303)the Natural Science Foundation of Xinjiang Uygur Autonomous Region (2017D01A79)
文摘Populus euphratica Oliv.is a unique woody tree that can be utilized for vegetation restoration in arid and semi-arid areas.The effects of saline water irrigation(0.00, 2.93, 8.78 and 17.55 g/L NaCl solutions) on water transport and water use efficiency(WUE) of P.euphratica saplings were researched for improving the survival of P.euphratica saplings and vegetation restoration in arid and semi-arid areas of Xinjiang, China in 2011.Results showed that hydraulic conductivity and vulnerability to cavitation of P.euphratica saplings were more sensitive in root xylem than in twig xylem when irrigation water salinity increased.Irrigation with saline water concentration less than 8.78 g/L did not affect the growth of P.euphratica saplings, under which they maintained normal water transport in twig xylem through adjustment of anatomical structure of vessels and kept higher WUE and photosynthesis in leaves through adjustment of stomata.However, irrigation with saline water concentration up to 17.55 g/L severely inhibited the photochemical process and WUE of P.euphratica saplings, resulting in severe water-deficit in leaves and a sharp reduction in water transport in xylem.Thus, it is feasible to irrigate P.euphratica forest by using saline groundwater for improving the survival of P.euphratica saplings and vegetation restoration in arid and semi-arid areas of Xinjiang, China.
基金supported by the National Natural Science Foundation of China(Grant Nos.62305283,41975039,and 42075149)the Natural Science Foundation of Shandong Province(Grant No.ZR2021QD088)the Youth Innovation and Technology Support Program for Colleges and Universities in Shandong Province(Grant No.2021KJ008)。
文摘Investigation of the distribution,evolution,and interactions of atmospheric components on Mars is crucial for understanding its climate and environment.The Spectroscopy Spectrograph for the Investigation of Characteristics of the Atmosphere of Mars(SPICAM),an instrument on the Mars Express spacecraft launched by the European Space Agency,consists of an ultraviolet channel(118–320 nm)and a near-infrared channel(1000–1700 nm),which provides the most comprehensive vertical spectral dataset of the Martian atmosphere to date.This study analyzes the spectral data obtained from nadir observations of SPICAM's infrared channel during its first operational Martian year(January 2004 to November 2005)on the basis of the spectral theory of O_(2)molecular airglow and the radiative transfer mechanism of H2O in the atmosphere,retrieving the seasonal and global distributions of O_(2)(a^(1)△_(g))airglow intensity and H2O abundance.Results reveal a clear inverse correlation between O_(2)(a^(1)△_(g))airglow intensity and H2O abundance.This finding provides indirect evidence of an anticorrelation between O3 and H2O,given that O_(2)(a^(1)△_(g))airglow serves as a tracer for O3 photodissociation.This will contribute to a deeper understanding of Martian climatology,thereby further refining Martian photochemical models,and assisting in exploring the stability of the Martian atmosphere.
基金supported by National Natural Science Foundation of China (Grant Nos. 40875090, 40375002, 40775011)Natural Science Foundation of Guangdong Province (Grant No. 7035008)Tropical Marine Meteorological Science Foundation (Grant No. 200502)
文摘Our analysis of the surface aerosol and ultraviolet （UV） measurements in Pearl River Delta （PRD） region shows that the surface UV radiation is reduced by more than 50% due to high aerosol concentrations. This has important impacts on urban ecosystem and photochemistry, especially on ozone photochemical production over the region. The quantitative effect of aerosols on surface ozone is evaluated by analyzing surface observations （including ozone, ultraviolet radiation, aerosol radiative parameters） and by using radiative and chemical models. A case study shows that the aerosol concentrations and UV radiation are significantly correlated with ozone concentrations. The correlation coefficient between the aerosol optical depth （AOD） and the PM10 mass concentration is very high, with a maximum of 0.98, and the AOD and UV radiation/ozone is anti- correlated, with a correlation coefficient of-0.90. The analysis suggests that ozone productivity is significantly decreased due to the reduction of UV radiation. The noon-time ozone maximum is considerably depressed when AOD is 0.6, and is further decreased when AOD is up to 1.2 due to the reduction of ozone photochemical productivity. Because the occurring probability of aerosol optical depth for AOD550m≥0.6 and AOD340mm ≥1.0 is 47, and 55% respectively during the dry season （October, November, December, January）, this heavy aerosol condition explains the low ozone maximum that often occurs in the dry season over the Guangzhou region. The analysis also suggests that the value of single scattering albedo （SSA） is very sensitive to the aerosol radiative effect when the radiative and chemical models are applied, implying that the value of SSA needs to be carefully studied when the models are used in calculating ozone production.
文摘In order to obtain inexpensive and effective application of catalyst for photodegradation,Cu_(2)O powder was prepared by the simple and inexpensive electrodeposition method using surfactants such as glycerin(GLY),polyvinyl alcohol(PVA),poly(N-vinylpyrrolidone)(PVP)that helped the growth and nucleation of suspended particles.These particles were distinguished by atomic force microscopy(AFM),X-ray diffraction(XRD),field-emission scanning electron microscopy(FESEM)and high-resolution transmission electron microscopy(HRTEM).Diameter size of these obtained particles was found to reach to about 40 nm.In order to demonstrate the photodegradation efficiency of the copper oxide in the removal of organic malachite green oxalate(MG)dye,the catalyst was used both in calcination at 300°C and without calcination.Parameters such as the amount of catalyst,the concentration of dye,the pH of dye sol,and the temperature were calculated.Pseudo first order reactions according to Langmuir-Hinshelwood kinetics could be obtained from the result of photocatalytic reactions.Parameters such as energy activation(Ea),enthalpy of activation(ΔH0),entropy of activation(ΔS0)and free energy of activation(ΔG0)were calculated.The activation energy was equal to 11.719±1 and 11.083±1 kJ/mol for MG dye in the presence of Cu_(2)O nanoparticles in both two cases of calcination and without calcination respectively.
