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Methane and Nitrous Oxide Emissions from Three Paddy Rice Based Cultivation Systems in Southwest China

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Advances in Atmospheric Sciences 2006年第3期23卷 415-424页

作者：江长胜王跃思郑循华朱波黄耀郝庆菊 institute of Atmospheric Physics institute of Mountain Hazards and environment

To understand methane （CH4） and nitrous oxide （N2O） emissions from permanently flooded rice paddy fields and to develop mitigation options, a field experiment was conducted in situ for two years （from late 2002 to early 2005） in three rice-based cultivation systems, which are a permanently flooded rice field cultivated with a single time and followed by a non-rice season （PF）, a rice-wheat rotation system （RW） and a rice-rapeseed rotation system （RR） in a hilly area in Southwest China. The results showed that the total CH4 emissions from PF were 646.3±52.1 and 215.0±45.4 kg CH4 hm^-2 during the rice-growing period and non-rice period, respectively. Both values were much lower than many previous reports from similar regions in Southwest China. The CH4 emissions in the rice-growing season were more intensive in PF, as compared to RW and RR. Only 33% of the total annual CH4 emission in PF occurred in the non-rice season, though the duration of this season is two times longer than the rice season. The annual mean N2O flux in PF was 4.5±0.6 kg N2O hm^-2 yr^-1. The N2O emission in the rice-growing season was also more intensive than in the non-rice season, with only 16% of the total annual emission occurring in the non-rice season. The amounts of N2O emission in PF were ignorable compared to the CH4 emission in terms of the global warming potential （GWP）. Changing PF to RW or RR not only eliminated CH4 emissions in the non-rice season, but also substantially reduced the CH4 emission during the following rice-growing period （ca. 58%, P〈0.05）. However, this change in cultivation system substantially increased N2O emissions, especially in the non-rice season, by a factor of 3.7 to 4.5. On the 100-year horizon, the integrated GWP of total annual CH4 and N2O emissions satisfies PF〉〉RR≈RW. The GWP of PF is higher than that of RW and RR by a factor of 2.6 and 2.7, respectively. Of the total GWP of CH4 and N2O emissions, CH4 emission contributed to 93%, 65% and 59% in PF, RW and

关键词： cultivation systems permanently flooded rice fields CH4 N2O global warming potential (GWP)

Performance and microbial community analysis of an algal-activated sludge symbiotic system: Effect of activated sludge concentration

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Journal of environmental Sciences 2019年第2期31卷 121-132页

作者： Li Sun Wei Zuo Yu Tian Jun Zhang Jia Liu Ni Sun Jianzheng Li State Key Laboratory of Urban Water Resource and environment (SKLUWRE) School of EnvironmentHarbin Institute of Technology

It was focused on the effect of different sludge concentrations on the performances of an algal-activated sludge symbiotic system in terms of wastewater treatment, algal-activated sludge characteristics and community structure. The results showed that the highest nutrient removal efficiencies were obtained in the reactor R^2 with soluble chemical oxygen demand(sC OD), ammonia nitrogen(NH_4^+-N) and phosphate(PO_4^(3-)-P) removal efficiencies of(90.6 ± 2.3)%,(97.69 ± 2.6)% and(83.81 ± 2.3)%, respectively. Further investigation exhibited that sludge concentration has a great effect on the dissolved oxygen(DO) concentration, the pH, the growth of algae and the extracellular polymeric substance(EPS) production, which resulted in influencing the settleability and the performance of symbiotic system. The denaturing gradient gel electrophoresis(DGGE) analysis demonstrated that the sludge concentration had a selective power for particular members of algae. Meantime, the stimulated algal population would selectively excite the members of bacteria benefited for the formation of algal-bacterial *** variation of microbial compositions, which was influenced by the different sludge concentrations, might be ultimately responsible for the different treatment performances.

关键词： Algal-activated sludge symbiotic system Sludge concentration Wastewater treatment Algal and bacterial communities

Variation in seed traits and seedling vigour of Cordia africana *** in Ethiopia

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Journal of Forestry Research 2017年第5期28卷 925-934页

作者： Abayneh Derero Genene Tesfaye Zewdie Woldemariam Ethiopian environment and Forest Research institute

Cordia africana is a very important indigenous tree species for timber and other products and services in Ethiopia. Seed traits and seedling vigour of seeds from 12 provenances of the species were compared. Mean seed mass for each provenance was assessed for 1000 seeds in 10 replications, and seed length and width were measured for 100 seeds in four replications per provenance. Germination was assessed in a glasshouse taking 400 seeds from each provenance. Root collar diameter and height of 440 seedlings grown in a nursery for 290 days in Addis Ababa were measured. Seed length, seed width, seed mass, and shoot height and root collar diameter of seedlings showed significant differences (P environmental variables revealed significant positive correlations between seed width and germination percentage, seed width and altitude, seed width and longitude and seed length and latitude. Negative correlations were obtained between seed width and temperature, seed width and rainfall, seed mass and temperature, and germination and temperature of the seed source. As expected, differences in seed trait did not explain the variability in seedling vigour. Determining quantitative variations in seed traits and seedling vigour among provenances and the patterns along environmental gradients are essential for informing decisions on the tree improvement programme of the species.

关键词： Clinal Correlation environmental gradient Improvement Quantitative

Wood substitution potential in greenhouse gas emission reduction–review on current state and application of displacement factors

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Forest Ecosystems 2021年第3期8卷 548-565页

作者： Tanja Myllyviita Sampo Soimakallio Jáchym Judl Jyri Seppälä Finnish environment institute Helsinki Finland

Background:Replacing non-renewable materials and energy with wood offers a potential strategy to mitigate climate change if the net emissions of ecosystem and technosystem are reduced in a considered time *** factors(DFs)describe an emission reduction for a wood-based product or fuel which is used in place of a non-wood *** aims of this review were to map and assess DFs from scientific literature and to provide findings on how to harmonise practices behind them and to support coherent ***:Most of the reviewed DFs were positive,implying decreasing fossil GHG emissions in the *** vast majority of the reviewed DFs describe avoided fossil emissions either both in processing and use of wood or only in the latter when wood processing emissions were considered *** of the reviewed DFs included emissions avoided in post-use of harvested wood products(HWPs).Changes in forest and product carbon stocks were not included in DFs except in a few single ***,in most of the reviewed studies they were considered separately in a consistent way along with *** for wood energy,construction and material substitution were widely available,whereas DFs for packaging products,chemicals and textiles were *** than half of DFs were calculated by the authors of the reviewed articles while the rest of them were adopted from other ***:Most of the reviewed DFs describe the avoided fossil GHG *** DFs may provide insights on the wood-based products with a potential to replace emissions intensive alternatives but they do not reveal the actual climate change mitigation effects of wood *** way DFs should be applied and interpreted depends on what has been included in *** the aim of DFs is to describe the overall climate effects of wood use,DFs should include all the relevant GHG flows,including changes in forest and HWP carbon stock and post-use of HWPs,however,based on this lite

关键词： substitution potential replace

Preparation of Ferrioxalate Submicrorods/Graphene Composites and Their Photocatalytic Properties

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Journal of Materials Science & Technology 2014年第2期30卷 117-122页

作者： Min Fu Yun Zhao Qingze Jiao School of Chemical Engineering and the environment Beijing Institute of Technology

Ferrioxalate submicrorods/graphene composites were synthesized through a simple solvothermal process in a mixture of ethylene glycol and water. The in situ growth of ferrioxalate submicrorods and the reduction of graphene oxide （GO） were completed in a one-step reaction. Fourier transform infrared and Raman spectroscopy confirmed the reduction of GO. Uniform rod-like ferrioxalates with diameter of about 600 nm and length of several micrometers were well distributed on the graphene sheets. As-obtained composites exhibited better photocatalytic properties than pure ferrioxalate submicrorods. The influence of different contents of GO on photocatalytic performance was also investigated. A possible photocatalytic mechanism of ferrioxalate submicrorods/graphene composites was proposed.

关键词： Ferrioxalate submicrorods Graphene Photocatalysis

Synthesis and THF Accompanied Crystal Structure of 11H-Naphtho[1',2':5,6]- pyrano[2,3-d]pyrimidin-11(10H)-one

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Chinese Journal of Structural Chemistry 2008年第12期27卷 1469-1474页

作者：张立军杨希泉李加荣史大昕张玲范妍秋 School of Chemical Engineering & the environment Beijing Institute of Technology

8,9,12-Trihydro-9,9-pentamethylene- 12-（3-nitrophenyl）- 11H-naphtho[ 1＇,25,6]- pyrano[2,3-d]pyfimidin- 11 （10H）-one 1, another conversion product of Ffiedlandler reaction, has been synthesized by the reaction of 2-amino-4-（3-nitrophenyl）-4H-benzo[f]chromene-3-carbonitrile 2 with cyclohexanone in the presence of Lewis acid catalysts. The crystal of the title compound 1 THF solvate, C60H62N6O10, was obtained and determined by X-ray diffraction method. The crystal is of triclinic, space group P1 with a = 11.4633（11）, b = 12.6247（12）, c = 19.658（2）A, α = 72.642（8）, β = 89.045（9）, γ = 68.340（5）°, V = 2509.6（4）, Z = 2, De = 1.359 g/cm^3, F（000） = 1088, Mr = 1027.16, the final R = 0.0674 and wR = 0.1869 with Ⅰ 〉 2σ（Ⅰ） and the goodness-of-fit S = 1.045 on F^2. The pyrimidine ring has an envelope conformation, linked with a six-membered ring through a spiro C atom. The crystal packing of 1 THF solvate is stabilized by N-H…O hydrogen bonds, and π-π stacking interaction occurs between two adjacent nearly planar molecules of 1.

关键词： synthesis crystal structure tacrine analogue X-ray crystallography

Relationships Between Abundance of Microbial Functional Genes and the Status and Fluxes of Carbon and Nitrogen in Rice Rhizosphere and Bulk Soils

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Pedosphere 2014年第5期24卷 645-651页

作者： NIE San-An XU Hui-Juan LI Shun LI Hu SU Jian-Qiang Key Laboratory of Urban environment and Health Institute of Urban Environment Chinese Academy of Sciences

Rapid nitrogen(N) transformations and losses occur in the rice rhizosphere through root uptake and microbial activities. However,the relationships between rice roots and rhizosphere microbes for N utilization are still unclear. We analyzed different N forms(NH+4,NO-3, and dissolved organic N), microbial biomass N and C, dissolved organic C, CH4 and N2O emissions, and abundance of microbial functional genes in both rhizosphere and bulk soils after 37-d rice growth in a greenhouse pot experiment. Results showed that the dissolved organic C was significantly higher in the rhizosphere soil than in the non-rhizosphere bulk soil, but microbial biomass C showed no significant difference. The concentrations of NH+4, dissolved organic N, and microbial biomass N in the rhizosphere soil were significantly lower than those of the bulk soil, whereas NO-3in the rhizosphere soil was comparable to that in the bulk soil. The CH4 and N2O fluxes from the rhizosphere soil were much higher than those from the bulk soil. Real-time polymerase chain reaction analysis showed that the abundance of seven selected genes, bacterial and archaeal 16 S rRNA genes, amoA genes of ammonia-oxidizing archaea and ammonia-oxidizing bacteria, nosZ gene, mcrA gene, and pmoA gene, was lower in the rhizosphere soil than in the bulk soil, which is contrary to the results of previous studies. The lower concentration of N in the rhizosphere soil indicated that the competition for N in the rhizosphere soil was very strong, thus having a negative effect on the numbers of microbes. We concluded that when N was limiting, the growth of rhizosphere microorganisms depended on their competitive abilities with rice roots for N.

关键词： ammonium-oxidizing archaea ammonia-oxidizing bacteria CH4emission microbial biomass N2O emission organic C organic N

Aerosol light absorption in a coastal city in Southeast China:Temporal variations and implications for brown carbon

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Journal of environmental Sciences 2019年第6期31卷 257-266页

作者： Yuqing Qiu Xin Wu Yanru Zhang Lingling Xu Youwei Hong Jinsheng Chen Xiaoqiu Chen Junjun Deng Center for Excellence in Regional Atmospheric environment Institute of Urban Environment Chinese Academy of Sciences Key Laboratory of Urban environment and Health Institute of Urban Environment Chinese Academy of Sciences University of Chinese Academy of Sciences Fujian environmental Monitoring Station institute of Surface-Earth System Science Tianjin University

Light-absorbing carbonaceous aerosols including black carbon(BC) and brown carbon(BrC)play significant roles in atmospheric radiative properties. One-year measurements of aerosol light absorption at multi-wavelength were continuously conducted in Xiamen,southeast of China in 2014 to determine the light absorption properties including absorption coefficients(σabs) and absorption ?ngstr?m exponent(AAE) in the coastal *** absorptions of BC and BrC with their contributions to total light absorption were further quantified. Mean σabsat 370 nm and 880 nm were 56.6 ± 34.3 and 16.5 ± 11.2 Mm-1,respectively. σabspresented a double-peaks diurnal pattern with the maximum in the morning and the minimum in the afternoon. σabswas low in warm seasons and high in cold seasons. AAE ranged from 0.26 to 2.58 with the annual mean of 1.46, implying that both fossil fuel combustion and biomass burning influenced aerosol optical properties. σabsof BrC at 370 nm was 24.0 ± 5.7 Mm-1, contributing 42% to the total absorption. The highest AAE(1.52 ± 0.02) and largest BrC contributions(47% ± 4%) in winter suggested the significant influence of biomass burning on aerosol light absorption. Long-distance air masses passing through North China Plain and the Yangtze River Delta led to high AAE and BrC contributions. High AAE value of 1.46 in July indicated that long-range transport of the air pollutants from intense biomass burning in Southeast Asia would affect aerosol light absorption in Southeast China. The study will improve the understanding of light absorption properties of aerosols and the optical impacts of BrC in China.

关键词： Light absorption Brown carbon Black carbon Absorption Angstrom exponent Biomass burning Western Taiwan Strait

Theoretical Studies of Water’s and Methanol’s Effects on Alcoholysis of N-Benzyl-3-oxo-β-sultam

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Chinese Journal of Structural Chemistry 2007年第9期26卷 1118-1124页

作者：孙孝敏何茂霞冯大诚蔡政亭 environment Research institute Shandong University institute of Theoretical Chemistry Shandong University

The mechanisms about the water’s and methanol’s effects on the alcoholysis of N-benzyl-3-oxo-β-sultam together with their differences have been studied by using density func- tional theory at the B3LYP/6-31G＊ level. The results, in comparison with a previous study on the relative reaction without the assistance of water and methanol, show that the added water or methanol can remarkably reduce the energy barrier of alcoholysis reaction of N-benzyl-3-oxo- β-sultam and the most favorite pathway is the breaking of C–N bond instead of S–N. It is also found that the reaction energy barrier of methanol-assisted alcoholysis is a little higher than that of the water-assisted one.

关键词： alcoholysis N-benzyl-3-oxo-β-sultam water-assisted methanol-assisted