In order to correctly use the column-averaged atmospheric COdry-air mole fraction(XCO) data in the COflux studies, XCOmeasurements retrieved from the Orbiting Carbon Observatory-2(OCO-2) in 2015 were compared with tho...In order to correctly use the column-averaged atmospheric COdry-air mole fraction(XCO) data in the COflux studies, XCOmeasurements retrieved from the Orbiting Carbon Observatory-2(OCO-2) in 2015 were compared with those obtained from the global ground-based high-resolution Fourier Transform Spectrometer(FTS) participating in the Total Carbon Column Observing Network(TCCON). The XCOretrieved from three observing modes adopted by OCO-2, i.e., nadir, target, and glint, were separately validated by the FTS measurements at up to eight TCCON stations located in different areas. These comparisons show that OCO-2 glint mode yields the best qualitative estimations of COconcentration among the three operational approaches. The overall results regarding the glint mode show no obvious systematic biases. These facts may indicate that the glint concept is appropriate for not only oceans but also land regions. Negative systematic biases in nadir and target modes have been found at most TCCON sites. The standard deviations of XCOretrieved from target and nadir modes within the observation period are similar, and larger than those from glint mode. We also used the FTS site in Beijing, China, to assess the OCO-2 XCOin 2016. This site is located in a typical urban area, which has been absent in previous studies. Overall, OCO-2 XCOagrees well with that from FTS at this site. Such a study will benefit the validation of the newly launched TanSat products in China.展开更多
The investigation of the biodegradability and methane potential of bacterial pre-treated miscanthus sinensis has been carried out.One percent solution of Bacta-sile:A silage promoter was used to pre-treat miscanthus s...The investigation of the biodegradability and methane potential of bacterial pre-treated miscanthus sinensis has been carried out.One percent solution of Bacta-sile:A silage promoter was used to pre-treat miscanthus sinensis at 25℃.The anaerobic digestion experiments were carried out at 25℃ and 35℃ in batch experiments.The organic loading rates(OLR)varied between 1.25 g and 7 g in different batch reactors.The results showed that the highest methane concentration was 57% from digester 1 while the lowest methane produced was 38% from digester 3.The low methane production from digester 3 was attributed to temperature changes and poor organic loading rate.Bacterial pretreatment aided biodegradation of miscanthus at 25℃.Operating temperature of 25℃ had a great effect on digestion experiments resulting to longer required Hydraulic Retention Time(HRT).展开更多
The methane potentials of cyanobacteria and chlorella have been investigated in eight different lab scale reactors at 25℃for three-day Hydraulic Retention Time(HRT).Autoclavation pre-treatment was applied to the cyan...The methane potentials of cyanobacteria and chlorella have been investigated in eight different lab scale reactors at 25℃for three-day Hydraulic Retention Time(HRT).Autoclavation pre-treatment was applied to the cyanobacteria to aid digestion,while the Chlorella was obtained and digested in powdery form.The organic loading rates were 1g VS,2 g VS,3 g VS,4 g VS,5 g VS,6 g VS,7 g VS,8 g VS and 9 g VS.Methane production rates increased with increasing loading rates and started declining at loading rate higher than 7 g VS,while the HRT was kept constant.The highest methane production rates for cyanobacteria and chlorella were(78±25)mL/(L·d)and(100±25)mL/(L·d),respectively,at loading rate of 7 g VS.Digester instability occurred at loading rates of 8 g VS and 9 g VS with higher accumulation of methane concentrations.Lipid compositions of both feeds were close and the methane production potentials of both biomasses were also close and followed the same trend.展开更多
An atmospheric-pressure carbon dioxide(CO_2) plasma jet(CPJ) produced by alternating current driven non-thermal arc plasma torch is presented.The discharge features of CPJ and their non-linear behavior are analyzed ba...An atmospheric-pressure carbon dioxide(CO_2) plasma jet(CPJ) produced by alternating current driven non-thermal arc plasma torch is presented.The discharge features of CPJ and their non-linear behavior are analyzed based on the temporal evolution of voltage and current.With the increase of gas flowrate,the quantities of the current and voltage spikes increase in an operation cycle of power supply.The spatial gas temperature distribution is obtained by the gray value method,which basically agrees well with that of determined by the diatomic molecule of OH fitting method in experimental errors.展开更多
大气二氧化碳(CO_2)浓度和温度的增加是全球气候变化的两个最主要特征。目前空气中的CO_2浓度已从1800年的不到280μmol/mol上升到391μmol/mol,预测本世纪末最高将增至936μmol/mol。伴随CO_2及其它温室气体增强的温室效应,相比1980—1...大气二氧化碳(CO_2)浓度和温度的增加是全球气候变化的两个最主要特征。目前空气中的CO_2浓度已从1800年的不到280μmol/mol上升到391μmol/mol,预测本世纪末最高将增至936μmol/mol。伴随CO_2及其它温室气体增强的温室效应,相比1980—1999年,2100年之前全球地表平均气温将增高1.5—4.0℃。水稻是人类最重要的食物来源,为全球半数以上人口提供营养。在介绍CO_2浓度和温度增高试验平台的基础上,系统总结了CO_2浓度和气温这两个重要的环境因子特别是两者的交互互作对水稻影响的实验进展,内容包括光合作用、生育进程、分蘖发生、物质生产、籽粒产量、受精过程、碳氮代谢、稻米品质以及水稻/杂草竞争等方面。结果表明,作为光合作用的底物,大气CO_2浓度增高对水稻生产力的直接影响通常是有益的;相反,气温升高及其与CO_2的互作对水稻各生长过程的影响变异很大(从负到正),反映了处理因子(包括CO_2-温度处理水平和时间)、供试品种及其生长条件之间复杂的交互作用。目前这一方向有限的认识多来自于封闭或半封闭气室的研究,未来研究的重点是利用稻田T-FACE(Temperature-Free Air CO_2Enrichment)技术结合气室试验展开更多更深入的学科交叉研究,研明CO_2浓度与温度的交互作用对水稻关键生长过程的影响,并找出这些互作效应的生物学机制,增强人们对气候假定情景下水稻响应的预测能力,进而更加有效地制订出应对气候变化的适应策略。展开更多
Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysi...Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysis, we found that： （1） up to 82 mole% methane exists in the primary inclusions hosted in the reservoir volcanic rocks; （2） high CH4 inclusions recognized in the volcanic rocks correspond to CH4-bcaring CO2 reservoirs that are rich in helium and with a high ^3He/^4He ratio and which show reversed order of 813C in alkane; （3） in gas reservoirs of such abiotic methane （〉80%） and a mix of CH4 and CO2, the enclosed content of CH4 in the volcanic inclusions is usually below 42 mole%, and the reversed order of δ^13C in alkane is sometimes irregular in the corresponding gas pools; （4） a glassy inclusion with a homogeneous temperature over 900℃ also contains a small portion of CH4 although predominantly CO2. This affinity between gas pool and content of inclusion in the same volcanic reservoirs demonstrates that magma-originated gases, both CH4 and CO2, have contributed significantly to the corresponding gas pools and that the assumed hydrocarbon budget of the bulk earth might be much larger than conventionally supposed.展开更多
基金Supported by the TanSat Project(2011AA12A104)under a contract with the National Science and Technology Support Program of China
文摘In order to correctly use the column-averaged atmospheric COdry-air mole fraction(XCO) data in the COflux studies, XCOmeasurements retrieved from the Orbiting Carbon Observatory-2(OCO-2) in 2015 were compared with those obtained from the global ground-based high-resolution Fourier Transform Spectrometer(FTS) participating in the Total Carbon Column Observing Network(TCCON). The XCOretrieved from three observing modes adopted by OCO-2, i.e., nadir, target, and glint, were separately validated by the FTS measurements at up to eight TCCON stations located in different areas. These comparisons show that OCO-2 glint mode yields the best qualitative estimations of COconcentration among the three operational approaches. The overall results regarding the glint mode show no obvious systematic biases. These facts may indicate that the glint concept is appropriate for not only oceans but also land regions. Negative systematic biases in nadir and target modes have been found at most TCCON sites. The standard deviations of XCOretrieved from target and nadir modes within the observation period are similar, and larger than those from glint mode. We also used the FTS site in Beijing, China, to assess the OCO-2 XCOin 2016. This site is located in a typical urban area, which has been absent in previous studies. Overall, OCO-2 XCOagrees well with that from FTS at this site. Such a study will benefit the validation of the newly launched TanSat products in China.
文摘The investigation of the biodegradability and methane potential of bacterial pre-treated miscanthus sinensis has been carried out.One percent solution of Bacta-sile:A silage promoter was used to pre-treat miscanthus sinensis at 25℃.The anaerobic digestion experiments were carried out at 25℃ and 35℃ in batch experiments.The organic loading rates(OLR)varied between 1.25 g and 7 g in different batch reactors.The results showed that the highest methane concentration was 57% from digester 1 while the lowest methane produced was 38% from digester 3.The low methane production from digester 3 was attributed to temperature changes and poor organic loading rate.Bacterial pretreatment aided biodegradation of miscanthus at 25℃.Operating temperature of 25℃ had a great effect on digestion experiments resulting to longer required Hydraulic Retention Time(HRT).
文摘The methane potentials of cyanobacteria and chlorella have been investigated in eight different lab scale reactors at 25℃for three-day Hydraulic Retention Time(HRT).Autoclavation pre-treatment was applied to the cyanobacteria to aid digestion,while the Chlorella was obtained and digested in powdery form.The organic loading rates were 1g VS,2 g VS,3 g VS,4 g VS,5 g VS,6 g VS,7 g VS,8 g VS and 9 g VS.Methane production rates increased with increasing loading rates and started declining at loading rate higher than 7 g VS,while the HRT was kept constant.The highest methane production rates for cyanobacteria and chlorella were(78±25)mL/(L·d)and(100±25)mL/(L·d),respectively,at loading rate of 7 g VS.Digester instability occurred at loading rates of 8 g VS and 9 g VS with higher accumulation of methane concentrations.Lipid compositions of both feeds were close and the methane production potentials of both biomasses were also close and followed the same trend.
文摘An atmospheric-pressure carbon dioxide(CO_2) plasma jet(CPJ) produced by alternating current driven non-thermal arc plasma torch is presented.The discharge features of CPJ and their non-linear behavior are analyzed based on the temporal evolution of voltage and current.With the increase of gas flowrate,the quantities of the current and voltage spikes increase in an operation cycle of power supply.The spatial gas temperature distribution is obtained by the gray value method,which basically agrees well with that of determined by the diatomic molecule of OH fitting method in experimental errors.
文摘大气二氧化碳(CO_2)浓度和温度的增加是全球气候变化的两个最主要特征。目前空气中的CO_2浓度已从1800年的不到280μmol/mol上升到391μmol/mol,预测本世纪末最高将增至936μmol/mol。伴随CO_2及其它温室气体增强的温室效应,相比1980—1999年,2100年之前全球地表平均气温将增高1.5—4.0℃。水稻是人类最重要的食物来源,为全球半数以上人口提供营养。在介绍CO_2浓度和温度增高试验平台的基础上,系统总结了CO_2浓度和气温这两个重要的环境因子特别是两者的交互互作对水稻影响的实验进展,内容包括光合作用、生育进程、分蘖发生、物质生产、籽粒产量、受精过程、碳氮代谢、稻米品质以及水稻/杂草竞争等方面。结果表明,作为光合作用的底物,大气CO_2浓度增高对水稻生产力的直接影响通常是有益的;相反,气温升高及其与CO_2的互作对水稻各生长过程的影响变异很大(从负到正),反映了处理因子(包括CO_2-温度处理水平和时间)、供试品种及其生长条件之间复杂的交互作用。目前这一方向有限的认识多来自于封闭或半封闭气室的研究,未来研究的重点是利用稻田T-FACE(Temperature-Free Air CO_2Enrichment)技术结合气室试验展开更多更深入的学科交叉研究,研明CO_2浓度与温度的交互作用对水稻关键生长过程的影响,并找出这些互作效应的生物学机制,增强人们对气候假定情景下水稻响应的预测能力,进而更加有效地制订出应对气候变化的适应策略。
文摘Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysis, we found that： （1） up to 82 mole% methane exists in the primary inclusions hosted in the reservoir volcanic rocks; （2） high CH4 inclusions recognized in the volcanic rocks correspond to CH4-bcaring CO2 reservoirs that are rich in helium and with a high ^3He/^4He ratio and which show reversed order of 813C in alkane; （3） in gas reservoirs of such abiotic methane （〉80%） and a mix of CH4 and CO2, the enclosed content of CH4 in the volcanic inclusions is usually below 42 mole%, and the reversed order of δ^13C in alkane is sometimes irregular in the corresponding gas pools; （4） a glassy inclusion with a homogeneous temperature over 900℃ also contains a small portion of CH4 although predominantly CO2. This affinity between gas pool and content of inclusion in the same volcanic reservoirs demonstrates that magma-originated gases, both CH4 and CO2, have contributed significantly to the corresponding gas pools and that the assumed hydrocarbon budget of the bulk earth might be much larger than conventionally supposed.
